E L S E V I E R Inorganica Chimica Acta 266 (1997) 91-102

Transition metal (Mn, Co) and zinc formamidinate compounds having the basic beryllium acetate structure, and unique isomeric : iron compounds

F. Albert Cotton a,., L.M. Daniels ", L.R. Falvello b, J.H. Matonic ~, C.A. Murillo ~'¢'*, X. Wang a, H. Zhou ~

a Laboratm),for Molecular Structure and Bonding v.d .~epartment oj' Chemistry, Texas A&M University, College Station, TX 77843, USA t, Department of Inorganic Chemistry and Aragon Materials Science Institute, University ¢~f Zaragoza-C.S,I.C., 50009 Zaragoza, Spain

"Deparmzem of Chemistry. University of Costa Rico, Ciudad Universimria, Costa Rico

Received 31 October 19q6; accepted 13 February 1997

Abstract

Oxidation of Co2(DPhF).~ or hydrolysis of Co2 (DPhF) 4 ( DPhF =, N,N'-diphenyiformamidinate ) gives Co40( DPhF)6 ( I ). This tetranuclear compound consists of an oxygen atom centered in a tetrahedron of four-coordinate Co atoms with a DPhF bridge along each edge of the tetrahedron. An idealized T,t symmetry is also found tbr zinc, ll, and manganese, 111, analogs. The latter, Mn.sO(DPhF),~, crystallizes in a disordered fash~.~m so as to appear as two interpenetrating tetrahedra. Two #4-0 tetrairon compounds, namely, Fe40(DPhF)~, (IV) and FeaO(DBiPhF ~,,., V) (DBiPhF ~ N,N'-bisbiphenylformamidinate) are also described. These molecules are isomers of the Co, Zn and Mn molecules ~,~ tb:,,t they have the 'tetrahedron' of metal atoms badly distorted by a different distribution of the formamidinate ligands. Two opposite Fe,~Fe edges are doubly bridged, another two opposite edges are singly bridged and the remaining two edges are unbridged. The lengths of these three pairs of opposite edges are short, medium and long and the idealized molecular symmetry is only C~. Crystal data for I.loluene at ~60°C are: lriclinic, space group Pi, a~13.426(3), b~13.491(3), c~22.600(5) A, ot~99.55(3), fl~95.39(3), ~ 111,80(3) °, Z~ 2, For I | , 1,45CoH1o~ at ~ O0"C: orthorhombic, space group Pbca, a ~ 23.8113( 8), b ~ 23,406(2), c ~ 30.956(I) A, Z - 8. For i11i at =. 150°C: Irigonal, space group R3, a -= 23.440( I ), c ~ 10.708( I ) A, Z~ 3. For IV. 1.5 toluene at =~ 00"C: triclinic, space 8roupl'-[,a~ 14oq20(3),b~ 15,53913),t'~ 19.027(4) A, t ,~84.63(3) ,~85.67(3) , y~63.30(3)°,Z-~2. (C>1997EIsevierScienceS.A.

Keywords: Transllion illetal colliplexcs; i~orlllainidillalc coinl)lexcs; Dtnuclear complexes; Cry~tal structu~s

I. Introduction

While studying dinuclear compounds of the type Co..(DPhF),,, n = 3 or 4 I l l , we noticed that exposure of their toluene solutions to the laboratory atmosphere (for example, when cleaning the reaction flasks) gave a fast reac- tion to produce a bright blue color which slowly changed to give brown solids. The iron analogs behaved differently [ 2 ]. Solutions of the diiron tribridged compl-"x changed to clear brown then to an intense burgundy and finally gave a tan intractable solid. The tetrabridged iron compound produced a burgundy solution and then intractable solids.

A crystallographic study of the blue crystals of the cobalt compound revealed a tetranuclear core with tbur divalent Co atoms tetrahedrally positioned about an oxygen atom to give

* Corresponding authors. Tel.: + 1409-845 4432; fax: + 1409-845 935 I.

0020-1693/97/$17.00 © 1997 Elsevier Science S.A. All rights reserved Pll S0020-1693 ( 97 )05538-2

a structural moiety which is already familiar in inorganic chemistry. The [M40] 6' core in which the oxygen atom is at the center of a tetrahedron of divalent ions was character- ized for the first time in the so-called basic acetates of beryl- lium [31 and zinc [41, M40(OAc)6. In these compounds each metal atom also has a pseudo.tetrahedral arrangement of oxygen atones about it. Each of the six acetate groups forms a bridge betw~, a two metal atoms across each of the six edges el the tetrahe(~'on of metal ions. For M = Zn, other carboxy- late derivativ( • have been structurally characterized, such as the pivalate ar.~l benzoate [ 5 ], and there is a carbamate deriv-

ative [61. To our kntJwledge only two basic zinc compounds are

known in which the [Zn40] ~'~- core is complemented by nitrogen-donor ligands, i.e. diphenyltriazenate [7] and 7-azaindolate [8]. A few zinc compounds have been char- acterized in which the bridging ligand is a transition metal

9Z FA, £)~tton et al. / hwrgamca Chm~ica Acta 266 (1997) 91-102

tri~-chelated species 191 or a dialkylphosphorodithiolate [ lOl. For the latter a sult'ur-centcred analog is also known 1111.

For cobalt, a tetranuclear oxo-pivalate has b,:,:n described [ 12] but the structure was inferred only from spectroscopic data and the unit cell parameters. A search of the Cambridge Crystallographic Data Base revealed only three compounds containing the [Co4016+ moiety, namely 7-azaindolate [ 13 l, 3,5-dimethylpyrazolate [ 14 ] and the transition metal tris.chelatedfac- [ Ir(2-aminoethanethiolate) a ] [ 15 ].

A variation of the structure of [ M40] 6+-containing spe- cies is found for magnesium [ 16] and for a large number of copper [171 compounds of the type M40(/x-X)6'L4, X~ halide ion and L =donor species, In this type of com- pound each metal atom is bonded to five ligands, For man- ganese only a derivative of the latter class is known, namely [ Mn4(#a-O) l¢,(PPhMe.,)4 ] 1181,

Despite the wealth of known carboxylato axe-manganese 1191 and axe-iron [201 complexes, there are no reported analogs of the basic beryllium carboxylates. In this paper we describe the preparation and characterization of the first such compounds with formamidinate ligands for manganese, cobalt and zinc.

For iron(ll) we have prepared compounds that are stoi- chiometrieally the same but structurally different. Instead of having an essentially regular M,O core with one symmetrical N=C=N bridge across each of the six Fe,..Fe edges, these ironoco|,laining molecules possess a very distorted tetrahe° dron having two opposite Fe,, ,Fe edges bridged by two N- C~N ligand~ ( Fe,, .Fe ~ 2,85 A), two F¢,, ,F¢ edges bridged by only one N=C=N ligand (Fe, . ,Fe~ 3.18 A) and two unbridled edges with Fe,, .Fe-- 3,5 A,

2, I~perlmental

2, i, General procedures

XL-2OO spectrometer and UV-Vis spectra were recorded on a Cary 17-D spectrophotometer.

). 2. Preparation of Co40(DPhF)~ (I)

A mixture of CoCI 2 (O.100 g, 0.77 mmoi) and HDPhF (0.300 g, 1.5 mmol) was refluxed in toluene (20 ml) for 2 h. The solution was then cooled to - 78°(2 and LiOH. H~O (0.007 g, 0.20 mmol) and MeLi (1.5 ml, I M solution in THF/cumcne) were added. The mixture was warmed to room temperature and stirred for a further 2 h, filtered to remove L~C! and the filtrate evaporated to give a crude form of I. Recrystallization from toluene/hexanes gave X-ray quality crystals of I.CTHs. Yield: 0.150 g, 55%, Magnetic susceptibility: 5.8 BM (2.9/Co). IR (cm~*): 1679(s), 1646(s), 1601(s), 1587(s), 1571(m), 1548(s), 1525(m), 1463(m), 1377(m), 1323(s), 1222(s), 1210(s), 1171(w), 1154(w), 1077(w), 1026(w), 987(m), 928(w), 899(w), 759(s), 728(w), 697(s), 552(w), 526(w). UV-Vis: 630 nm (482 cm ~ t M-1), 590(sh).

2,3. Preparation of Zn40(DPhF)n (!!)

ZnCI2(HDPhF): ( I,O6 g, 2 mmol) was dissolved in tol- uene (30 ml), and the solution was cooled to -78°C and methyllithium (4 retool) was added. After stsrring for 2 h, the mixture was allowed to warm to room temperature and was filtered with the aid of Collie, The volume of the filtrate was reduced to 3/4 and a layer of hexanes ( 30 ml) was added. Air was then allowed into the reaction flask, A colorless crystalline solid Ibrmed in 4 days, After iilIoring, the solids were washed wilh hesanes (2 × 15 ml ) and then dried undcr vacuum to give 0,34 g o f l i (47%), IR (cm ~): 3056(w), 1650(w), 1606(s), 1560(s,br), 1486(s), 1340s (hr), 1228s (br), I178(m), 1080(w), I028(w), 984(m), 930(m), 891(w), 820(w), 755(s), 692(s), 641(w), 563(m), 521(m), 453(w). IH NMR (C~D¢,): 8 6.65-:7.17 (mull, 10H), 8.05 (s, IH).

Except where indicated, manipulations were carried out under an atmosphere of nitrogen using standard Schlenk roche niques, Samples for spectroscopic characterization we~v. pre- pared in a Vacuum Atmospheres drybox under an atmosphere of argon, Toluene and hexanes were purified by conventional methods and freshly distilled from Na/K alloy under nitroge, n immediately prior to use, C%(DPhF)~, C%(DPhF)~ and Fe:(DPhF)~ were prepared according to published proce- dures [I,21, Preparations of Mn~(DPhF).~ [211 and ZnCI:tHDPhF)~ 1221 arc given elsewhere, HDBiPhF (N,N'°bisbiphenylformamidine) was prepared according to a slightly mt~litied published procedure 123 ]. All diner r~a~ gents were purchased from Aldrich Chemical Co, IR Sl~Clra were obtained as Nujol mulls between KBr plates on a Perkin. Elmer 16-PC spcctrophotometrr; magnetic susceptibility measurements were taken on a Johnson-Matthey MSB- I bal- ance; ~H NMR ( 200 MHz) spectra were recorded on a Varian

2,4. Preparation of Mn~O(OPhF)~ fill)

In a t~ pical preparation, Mn~( DPhF)., (0.30 g, 0.34 mmol) was dissolved in toluene (25 ml) and then to the solution was added a layer of 30 ml of moist but oxygen- free hexanes. After a week light cream colored crystals were collected by filtration. They were washed with warm hexanes to yield 0.09 g (37%). No attempt was made to optimize this yield.

2.5. Prepara¢ion of I:c~O(DPhF)~ (IV)

MeduMa. A sample of Fo,~(DPhF).~ (0.250 g, 0.36 retool) was dissolved in 15 ml of toluene and 30 ml of hexanes, which had been briefly exposed to air, were layered on top of the solution. After I week crystals of IV- 1.5C~Hs were col- lected and washed with hexanes. Yield: 0.050 g, 20%. Mag- relic susceptibility: 6.75 BM (3.38/Fe). IR ( c m l ) :

I" A. Cotton el al l . / inorganica Chimico Acre 266 f !997) 91-102 93

1594(s), 1538(s,br), 1485(s), 1377(s), 1334(s), 1218(s), 1173(m), 1153(m), 1025(m), 999(m), 981(s), 926(m), 892(w), 834(w), 771(s), 759(s), 729(m), 696(s), 641(m), 615(w), 582(s), 545(w), 528(s), 512(m), 482(w), 455(w), 408(w). UV-Vis: except for a tail of a UV txansition, there was no distinguishable transition in the visible region.

Method b. Compound IV was also prepared from the reac- tion of FeCI2(HDPhF)2 (0.20 g, 0.39 mmol), LiOH-H20 (4 mg, 0.1 retool), and MeLt (0.9 mmol) in toluene (10 ml). LiCI which formed was filtered and the toluene evapo- rated to give IV. Yield: 0.109 g, 79%.

2.6, Preparation of Fe40(DBiPhF)n (V)

FeCI, (0,10 g, 0.78 mmol) was mixed in toluene ( 15 ml) with a sample of HDBiPhF (0.56 g, 1.5 mmoi) which con- tained a small amount of moisture. The solution was cooled to -780(2 and MeLt (1.5 ml) was added. The mixture was warmed to room temperature and filtered to remove LiCI. The filtrate was layered with 25 ml of hexanes and placed in the freezer. After 2 weeks crystals of V. C6HI4"4.5CTHx were collected by filtration and washed with hexanes. Yield: 0,025 g, 9%.

2,Z X-ray crysmllography

Crystals of each of I.CTH,, !1.1.45C~Hi4, I l l and IV, 1.5C7H, were mounted on the dps of quartz fibers and

cooled under a nitrogen stream on the diffractometer. Data for III were collected on a Nonius CAD4 using well-estab- lished techniques, including the use of 0-scans for absorption correction [24]. A Nonius FAST area-detector system pro- vided the data for the crystals containing I, II and IV. Details of the use of the FAST in our laboratory have been previously described [ 25 ]. These highly redundant data sets were cor- rected for Lorentz and polarization effects, but not for absorption.

In each case the structures were solved by locating a sig- nificant number of atoms (the metal atoms and some or all of the ligand atoms) via direct methods. The remainder of the ligand and solvent atoms were found in subsequent dif- ~'eren.~ce Fourier maps. The structures were refined and ana- lyzed using the SHELXTL programs [261. Data collection and structure refiaement data are summarized in Table 1.

Refinement of the structures of I. C7H8, 11. !.45C6H14 and IV. 1 .SCTHs proceeded in a routine manner, with the possible exception of a site in II apparently containing highly disor- dered isomers of hexane. Peaks at this site were refined as partially-occupied atoms of carbon, and refined acceptably, but no logical connectivity can be ascertained from a calcu- lation of bond distances. The important part of the structure (Zn40(DPhF)6) is well-ordered.

The structure of Mn40(DPhF)~ ( I l l ) is complicated by the disordering of the tetrahedral arrangement of the metal atoms by a pseudo-inversion center at the position of the oxygen atom, which generates eight partially-occupied Mn positions at the corncr~ of a or'be. For each tetrahedron of

Table I Cryslld and sinletu~ nfl|nement data liar complexes I, II, I!1 and IV

!' CIH, !1' 1.45Cnlt1,i III IV' I,SC1H,

Fttriilulii L'..tl l l,lCo.iN i ~O CNt.,,lol I,li l l~lldN I ~() f l.I i,-,oMll4N i ~O (-'.. ~ol 171tFe,tN i f l ) I 515.28 1573.84 1407.19 i 549,03

Spaet~ group P] Pbca R3 P] o (A) 13,426( 3 ) 23,8113( 8 ) 23.440( I ) 14.920( 35 b ~A) 13,491(3) 23.406(2) 23.4.40(I) 15.539(35 c {At 22.600(5) 30,956( I ) 10,708l I ) 19,027(4) ~ I °) 99.55(3) 90 90 84,63(3)

(° 5 95.39( 3 ) 90 90 85,67 ( 3 ) y t °) I 11.80(3) 90 120 63.30(35 v (A ~ ) 3693( I ) 17253(2) 5094.9(65 3921 ( I ) Z 2 8 3 2 D,~l~ (g em° '~) 1.362 1.227 1.376 1.312 ~(Mo Kot) (mm ~ 1) 0.938 1.148 0,782 0,780 Dlffractometer Nontus FAST Nonius FAST Nonius CAD4 Nonius FAST Temperature (°C) - 60 - 60 = 150 - 60 Ri (1> 2o'(1) ) 0.062 0.072 0.029 0.049 wR2 (I > 2or (I)) 0.134 0.170 0.072 0.120 RI (al l data) ~ 0.096 0,093 0.044 0,063 wR2 (all data) t, O. 152 0.189 0.077 O. 129 Weight parameters, a, b ' 0.062, 13.417 0.091, 57.65 0.031, 5.964 0.076, 2.343 Goodness.of-fit ( on F z) o 1.094 I, 108 1.0~ I 1.067

"RI =El IFol- IF~I I/~IFol. " wR2 = [~w( F,, 2 - F,2)2 /~w( F,,~)2I I/2. w= I / [0.2(Fo 2) + {ap)2+bp, p= [max(Fo ~ or0) + 2(Fc2) l/3.

u Quality-of-fit = [ ~w( I Fo21 - I F~ z I )21(N,,~- Npmme,~,~) ] I/2.

94 F,A C),tton etal./hwrganwa Chimica Acta 266 (1997) 91-102

Table 2 Atomic coordinates (× 104) and equivalent isotropic displaceme.nt parameters (~," × 10 t) for Co.,O(DPhF),~ (I .C~H,)

X ) ' .7. Ue q a

Co(1) 3151(I) Co(2) 1679(I) Co(31 4139(I) Co(4) 2275(I) O(1) 2769(3) Nil) 3409(4) N(2) 1805(4) N(3) 4509(4) N(4) 5379(4) N(5) 1825(4) N(6) 604(4) N(7) 979(4) N(8) 1255(4) N(9) 2508(4) N(10) 4227(4) N(II) 4123(4) N(12) 3636(4) C(1) 2631(51 C(2) 5407(5) C(3) 851(51 C(4) 863(S) C(5) 3528(5) C(6) 4167(5) C(11) 4332(5) C(121 4739(6) C(13) 5~0(61 C(141 6157(01 C(I~) 3745(6) CLIO) 48~(6) C(211 849(~) C(2~) 67(6) C(23) = 881(71

C(25) = 319(8)

C(311 ~84(~) C(3~) ~266(o) C(331 5~31(61 C(341 4~47(71 C($~) 389O(?) C(36) 3899(6) C(41) 6319(S) C(421 6849($) C(~) ~728(6) C(~) 8'083(6) C(4S) ?$42(6) C(46) 66?7(5) C(Sl) 1870(51 C(521 2460(6) C(53) ~48(71 C($41 ~077~7) C(55) I~00(71 C(~61 1398(61 Cl611 ~530(51 C(621 = 1180(51 C(63) ~2284(61 CffA,) =2732(61 C(~31 =2076(6) C(f~) =979(6) C(?I) 409(5)

5851( i ) 4726( 1 ) 6527( I ) 7244( 1 ) 6063(4) 728615) ~335(5) 5832(4) 7085(41 47~9~ 5) 4244,~ a) 5117, 5) 6934~ 5) 3800~ 4) 5146~ ~) 7739-1) 8614 4) 7650(6) 6350(6) 4350(5) 60&~(51 4127(51 8641(5) 7823(6) 7209(6) 7728(7) 8848(8) 9~6(7) 896~(6) 7492(6) 73~0(7) 7478(71 77~8(81 '/917(91 7`/`/6(7) 4646(6) 4759(61 38.~1(71 28O6(7) 2680( 7 ) 3599(6) 8088(6) 8584(6) 9597(7)

10114(7) 960?(6) 8604(6) 4783(6) 4272(7) 4343 ( 8 ) 4899 ( ~ ) 5411(~) 5354(?) 383.S(61 4338~6) 3893(?) 2987( ? )

2926(.~) 42.94(6)

1981(!) 2S7g( 1 ) 3313( 1 .~ 2885( 1 ) 2778(2) 1720(31 2008(3) 2067 ( 3 ) 2836(3) 1414(31 2102(31 3574 ( 3 ) 3507(3) 3020d 3) 3496~ 3) 3965~ 3) 3269~ ? ) 1698~ 3) 2370~ 3) 15521 3) 37331 3) 32911 3) 37991 3) 14461 3) 1076 ~3) 822(4) 949(4)

1322(41 1580(31 1810(4) 217~(41 2018(41 1487(.~) 1108(5) 1~63(41 1676(31 1~38(41 843(4) 869(4)

1305(41 1697(3) 301 !(31 2577(4) 2752(4) 3356(4) .~786(4) 3617(31 ?89(3) 475(4)

= I~ (41 -~408(41 oo 110(4)

496(4)

1915~41 1921(41

237~(4) 2369(4) 3895 ( 3 )

Table 2 (continued)

x y z Ueq a

C(72) 950(6) 3773(6) 4174(3) 34(2) C(73) 411(7) 3001(7) 4485(4) 46(2)

22( 1 ) C(741 -663(7) 2736(7) 4529(4 ) 49(2) 21( 1 ) C(75) - 1216(7) 3258(8) 4237(5) 62(3) 21 ( 1 ) C(76) -678(6) 4019(7) 3920(4) 49(2) 22( 1 ) C(81 ) 910(61 7784(6) 3763(4) 32(2) 22( ! ) C ( 8 2 ) - 183(61 7591(71 3684(4) 48(2) 26(!) C(83) -528(8) 8386(9) 3935(5) 58(3) 26( 1 ) C(84) 183(91 9349(8) 4279(4) 57(3) 23( I ) C(85) 1280(81 9542(8) 4387(4) 58(3) 22( I ) C(861 1641(7) 8753(6) 4119(4) 40(2) 24( ! ) C(91) 1903(5) 2637(5) 2856(4) 26(2) 24( I ) C(92) I :~04(61 1987(71 3278(4) 45(2) 26(I) C(93) 1181(81 881(81 3111(61 61(3) 28( 1 ) C(94) 653(7) 414(81 2528(7) 69(3) 25( I ) C(95) 733(7) 1034(71 2111(5) 64(3) 24( ! ) C(96) 1361(61 2168(71 2267(4) 43(2) 23( 1 ) C( 101 ) 5322(5) 5286(5) 3~99(3) 26(2) 23( ! ) C(102) 5864(6) 5954(6) 4270(4) 37(2) 26(2) C( 1031 6931(61 6133(71 4466(4) 48(2) 23(2) C(104) 7469(6) 5669(7) 4100(41 43(2) 23(2) C(105) 6939(6) 5003(7) 3539(4) 39(2) 23(2) C(106) 5883(6) 4824(6) 3343(4) 33(2) 22(2) C(III) 4491(61 7791(5) 4594(3) 25(2) 21(21 C(I12) 3919(61 6914(6) 4840(3) 33(2) 29(2) C(113) 4285(8) 6862(8) 5415(4) 52(2) 33(2) C(I141 5221(81 766~)(81 5751(41 51(2) 41(2) C(llS) 5789(7) 8549(8) 5519(41 49(2) 45(2) C( 1161 5417(61 8607(6) 49,13(31 33(2) 46(2) C(I:I) 3950(5) 9597(6) 3060(3) 23(2) ,16(21 C( 1221 ~049(6) 10306(6) 3141(31 32(2) 31(2) C(123) 5~38(6) 11253(6) 2922(4) 35(2) 41(21 C(1~4) 4868(6) I lSIN(?I 2621(41 ,t0(2 ) ~(~-) C(I~.~) :~480(61 I01~32(0) 2841(4) 35(2) 62(3) C(1261 3176(61 9880(6) ~769(3) ]1(2) 70(3) C(IS) 7~.~7191 i261(11) l~O(b) It9(,I) S0(21 C(251 S0~('~) 1707(91 ¢~68lS} ?I(:~) 25(~) C(351 8975( 141 1368(14) 718(81 130(61 34(2) C(451 9077( 171 678( 181 297(t}) 161 (~t) 48(21 C(551 8~01( 161 l~10( 161 = 253(8) 139(61 47(2) C(65) 7313(13) 469( I01 - 328(6) 91(41 45(2) C(751 6386( | l ) 1557(12) 135(81 116(51 33(2) 2.1(2 ) "U,,~ is defined as one third of 1h¢ Ir~ce of the onhogon~li~,~d {1,~ |onset

43(21 metal atoms, one unique atom resides on the three-fold axis 49( 2 41 (2) and the other on a general position so that the third and fourth 30(2) metal positions are generated by the three..tbld axis. Each of 30(2) the six bidentate ligands bridge a face of the 'cube' . at least 39(2) in the disordered model. It is probable that the positions of 5~ 3) the nitrogen and carbon atoms are actually slightly different

for the two orientations of the metal atoms, but not different 49( .]~ 3?(2) enough to actually be discernable via X-ray diffraction. This ~?(21 is indicated by the displacement parameters for the nitrogen 35~21 atoms, which are slightly more anisotropic than expected for 47(21 first-coo~ination-sphere atoms° .47(21 50(3) The origins! solution of the structure of Mn40(DPhF)6 38(2) was obtained in the centrosymmetric space group R3, in 27(2) which each metal position was given one-half of the site

(conr~..ed) occupancy. The structure refined normally, and at conver-

F.A, Comm et at/Inorganica Chimica Acre 266 f!997) 91-102 95

Table 3 Atomic coordinates (x 104) and equivalent isotropic displacement parameters (A 2 × 103) for Zn40(DPhF)¢, (ii, 1.45C~HI,O

Table 3 (continued)

x y z U~"

x y z U~q"

Zn(I) 36511) 4778(1) 226611) 25(1) Zn(2) 47211) 383011) 156111) 25(1) Zn(3) -42611) 369811) 229211) 25(I) Zn(4) -592(I) 463211) 1584(1) 24fl) O ( l ) -4611) 4237(2) 1928(1) 17(l) C(I) -259(2) 5732(2) 1921(2) 23(!) N(I) - 131(2) 5482(2) 2289(2) 2311) N ( 2 ) -317(2) 5450(2) 1552(2) 21(l) C ( 2 ) -8(2) 4247(2) 3060(2) 2411) C13) 142312) 4445(3) 190012) ~ (l) N(3) 453(2) 4388(2) 2846(2) 211) C(4) -92(2) 4239(2) 787(2) 24(!) N(4) -484(2) 4094(2) 2873(i) 21(I) N(5) 110212) 4901(2) 1940(2) 21(l) C(5) 170(2) 2740(3) 192012) 2311) N(6) 123412) 391812) 1853(2) 2211) C16) - 1 5 1 5 1 2 ) 4025(3) 197712) 2411) N(7) 406(2) 4231(2) 983(2) 2211) N(8) -577(2) 4225(2) 1005(i) 21(I) N(9) 19812) 301112) 155012) 25(I) N(10) 73 (2 ) 2996(2) 2298(2) 24(1) C(II) -284(2) 5762(2) 2680(2) 2411) N(II) -1182(2) 3570(2) 2004(2) 22(I) N(12) -1326(2) 4545(2) 1918(2) 21(!) C(12) -808(3) 6015(3) 2724(2) 32(2) C(13) -956(3) 626113) 311112) 44(2) C(14) -600(3) 6257(3) 3458(2) 46(2) C(15) 81(3) 5757(3) 3030(2) 34(2) C(16) -77(3) 601113) 341912) 42(2) C(21) - 26613) 5767(2) !!66(2) 26tl) C(2~) 17613) 6148(3) 110412) 36(2) C(23) 233(3) f~49(3~ 726(2) 46(2) C124) I,t614) oyto(3) 393(2) 55(2) C(251 --587(3) 5985(3) 444(2) 44(2) C(26) ~640(3) 5685(3) 83112) 33(2) C1311 ~08t2) 4348(3) 3070(2) 2411) C132) 137412) 4764(3) 3028(2) 3112) C(33) 1879(3) 4725(4) 3249(2) 43(2) C(34) 199113) 4254(4) 3S03(3) 58(2) C(351 1594(3) 3826(4) 3545(2) 53(2) C(36) 1080(3) 3872(3) 333312) 38(2) C(41) ~978(2) 4150(3) 3125(2) 26(I) C142) ~ I069(3) 4636(3) 3373(2) 35(2) C(43) - 1560(3) 4697(4) 3604(21 51(2) C(44) -1972(3) 4282(4) 3591(2) 52(2) C(45) - 1890(3) 3809(3) 3337(2) 42(2) C(46) -1400(2) 3737(3) 3098(2) 32(2) C(51) 1327(2) 5435(2) 1818(2) 24(I) C152) 120113) 5927(3) 2(H412) 3312) C(53) 140213) 6449(3) 190013) 46(2) C154) 174213) 6483(3) 154013) 55(2) C(55) 1864(3) .003(3) 1319(3) 52(2) C(56) 1660(3) 5477(3) 145012) 40(2) C161) 160212) 346113) 196112) 2511) C162) 191012) 3478(3) 2340(2) 3112) C163) 2265(3) 3027(3) 2443(2) 4112) C(64) 231513) 2566(3) 218213) 45(2) C(65) 2003(3) 254113) 180513) 4112) C166) 164412) 2990(3) 169417~ ~0~2) C(71) 864(2) 4441(3) 737~?~ 23(I)

(continued)

C(72) 1383(2) 4160(3) 751(2) 30(2) C(73) 1832(3) 4376(3) 515(2) 44(2) C(74) 1775(3) 4872(3) 272(2) 47(2) C(75) 1275(3) 5146(3) 266(2) 41(2) C(76) g!4(3~ 4940(3) 499(2) 30(2) C(81) - 1043(3) 4017(3) 772(2) 26(1) C(82) -989(3) 3537(3) 510(2) 38(2) C(83) - 1443(3) 3330(3) 284(2) 51(2) C(84) - 1961(3) 3589(4) 317(3) 52(2) C ( 8 5 ) -2021(3) 4056(3) 578(2) 43(2) C(86) - 1564(2) 4272(3) 808(2) 31(2) C(91) 102(2) 2693(2) 1173(2) 26(1) C(92) 443(3) 2771(3) 810(2) 36(2) C(93) 342(3) 2452(3) 438(2) 50(2) C(94) - 1 0 9 ( 4 ) 2076(3) 417(3) 59(2) C(95) -450(3) 2017(3) 768(3) 51(2) C(96) -357(3) 2315(3) !144(2) 36(2) C(101) 26.(2) 2727(2) 2679(2) 23(I) C(102) -65(3) 2723(3) 3047(2) 36(2) C(103) 137(3) 2482(3) 3427(2) 46(2) C(I~) 660(3) 2240(3) 3439(3) 48(2) C(105) 985(3) 2234(3) 3078(2) 44(2) C(106) 799(3) 2479(3) 2694(2) 34(2) C(IlI) -1412(2) 3035(3) 1888(2) 25(I) C(112) - 1 7 6 6 ( 3 ) 2983(3) 1532(2) 34(2) C(113) - 1968(3) 2452(31 1407(2) 48(2) C(114) -1814(3) 1971(3) 1627(3) 52(2) C(115) - 1466(3) 2012(3) 1981(2) 42(2) C(116) - 1265(3) 2541(3) 2118(2) 32(2) C ( 1 2 1 ) - 1674(2) 5003(3) 2046(2) 24(!) C(122) -1717(2) 5492(3) 1786(2) 29(2) C(123) -2048(~ 5949(3) 1916(2) 37(2) C(124) - 2332(3) 5930(3J 2302(2) 41(2) C(125) -~ 2293(3) 5451(3) 2560(2) 38(2) C(126) = 1961(2) 4995(3) 2432(2) 32(2) C(200) 1530{13) 3 9 4 2 ( ! 1 ) 5436(8) 70 C(201) 165413) 3397(3) 5230(3) 70 C1202) !87214) 2951)13) 5475(3) 70 C(203) 190914) 2405(3) 5299(3) 70 C(204) 1728(4) 2307(3) 4878(3) 70 C1205) 151014) 2753(4) 4634(3) 70 C(206) 1474(3) 3298(4) 4810(3) 70 C(301) 130(4) 4394(5) 4496(5) 100 C(302) 372(5) 4808(5) 4250(5) 100 C(303) 163615) 2203(4) 4485(4) 80 C(304) 1823(4) 3442(3) 5573(3) 80 C(305) 1944(5) 5568(4) 4414(3) I00 C(306) 2173(6) 6202(4) 4483(4) I00 C(308) 1053(8) 6952(4) 5798(4) 100 C1309) 1519(7) 6858(3) 5492(4) 100 C1310) 979(7) 6489(4) 555114) 100 C(311) 1515(6) 6446(3) 5119(4) I00 C(312) 160215) 6077(3) 4739(3) I00 C(313) 1348(8) 7104(4) 5846(4) !00 C(314) 1872(6) 6441(3) 4826(4) iO0 C(315) 721(7) 6564(4) 5695(5) 100 C(316) 1784(8) 6977(4) 5(47(4) 100 C(317) 1647(6) 6692(3) 5272(4) I00 C(318) 1736(3) 4117(3) 5297(2) 100 C(319) 2373(5) 5793(4) 4291(4) 100 C1320) 2044(8) 7375(4) 5695(5) 100 C(321) 149213) 4095(3) 4828(2) 100

(continued)

9~ ~:A. Cotton et al. / Im,rganica Chimwa Acta 266 f 1997) 91-102

T ~ k 3 (conunued)

x y z U~q"

C(322) 2905(6) 6806(4) 4557(5) 100 C(323) 2737(6) 6291(4) 4356(5) 100 C(324) 1787(4) 2601(3~ 5252(3) 100 C(325) 1457(3) 3573(3) 5156(3) 100 Ct326) 1176(7) 6814(4) 5664(4) 100

* U~ is defined as one third of the trace of the onhogonalized U u tensor.

gence the value of wR2 (all data) was 0.165. However, although the arrangement of the ligands is centrosymmetric, we proposed that there was no reason why the relative occu- pancies of the two Mn4 tetrahedra should be exactly 50:50, so the symmetry was lowered ,a the non-centrosymmetric space group R3, and the relative occupancy of the two group,; of metal atoms was allowed to refine. The refinement pro. ceeded without event, and the residuals dropped dramatically, the final value ofwR2 (0.077) being less than half of its value in the centrosymmetric space group. The occupancies of the two groups refined to 0.377:0.623 (2) for Mn( 1,2):Mn(3,4). The possibility that the crystals might be inversion twins was investigated, but evidence of such twinning was not found.

Crystals of V. C6Ht4' 4.5C~Hs were also studied, and the structure was solved and refined. The large Fe40(DBiPhF)~ molecule refined cleanly, including one phenyl group that exhibits a slight disorder. However. difference maps revealed ~even distinct areas in the interstices apparently containing highly disor4ered solve~ molecules (toluene and hexanes). Since the structure and configuration of the main molecule was ¢1¢~, no additional attempt to m~xlel the disordered sol° vent regions was made. The dintensions mid contigurati,m of the Fe~O(=NCN=). core in V are essentially the same as those in IV *,

Atomic coordinates tbr i, ii, i l i and iV are given in Table~ 2:5, respectively. Important distances and angles tbr i and II are given in Table 6. Geometric data for III and IV

listed in Tables 7 and 8, respectively,

3, Results and discussion

3, I, Syntheses

The tribridged dinuclear compound Co:(DPhF)~ reacts rapidly with atmospheric oxygen to produce a blue solution.

' ~ ' s ~ s of V. C~H,a, 4.5C~H. f ¢ i , Ihe a ~ o c l i a l c sp~c~ group ( ? : c with ~'~11 Fa r~c rs ~ ~ 34,735 (9), h ~ 27,650(9), c ~ 35,254(8) A, ~ 113.41(I) ~. V~31083 A ~ ~md Z~8, Refinement of 1651 ~ ¢ r s with 136=t5 u~ique tiara gave t'~stduals of wR2~0.29. RI ~0.16 (for MI d~a) ~1 wR2~0,~.5, R1-0,10 for the 9023 dala havtlt~/>2(~y(I)), I ~ t bond distances ~ Fe(I)..,F¢(2) ~2,818(2), Fe(I),,,F¢(3) ~ 3,='ff)9,(2), Fe(t) .,.Fe(4) ~ 3,512(2), Fe(2),,,F¢(3) ~ 3,502(2), Fe(2),,, Fe(4)~-3,224(2), Fe(3),,,Fe(4)~-2,843(2), Fe(I)-.-O~i,961(6), F'¢(2)~0 ~ - 11 966,(6), F¢(3)=0-- 1,955(6), F~(4)=O,= 1,948(6), all P~-N t,# the I ~ 2,0,g=2,0~ A, See also Section 5,

Table 4 Atomic coordinates (X 10 4) and equivalent isotropic disnlacement parameters (A 2 × 10 ~) for Mn40( DPhF)6 (llI)

x y Z Ueq a

Mn(1) 3333 Mn(2) 2408(I) Mn(3) 3333 Mn(4) 4258(I) O 3333 N(1) 2314(2) N(2) 1860(2) N(3) 4299(2) N(4) 4798(2) C(II) 2215(3) C(12) 1660(3) C(13) 1594(3) C(14) 2087(3) C(15) 2644(3) C(16) 2710(3) C(I) 1828(2) C(21) 1305(2) C(22) 1396(2) C(23) 872(2) C(24) 246(2) C(25) 151(2) C(26) 675(2) C(31) 4395(3) C(32) 3912(2) C(33) 3983(3) C(34) 4551(3) C(35) 5029(3) C(36) 4947(3) C(2) 4~!8(2) C(41) 53S6(2) C(4)) ~249(~) C(43) 57~1(~) C(4a) ~398(2) C(45) 6~11(2) C(46) 599~(2)

-3333 -3864(!) -3333 -2801(!) -3333 -4308(2) - 3754(2) -2406(2) -2876(2) -4835(2) -5457(2) -5955(2) -5848(2) -5234(2) -4730(2) -4194(2) - 3674(2) - 3040(2) -2945(2) -3475(2 ) -4094(2) =4201(2) -1874(2 ) -1964(2) = 1449(2) -839(3) =745(2)

= 1257q 2) ,2474q 2)

= 29~|q 2) : 3590~ 2) =~ ~715q3)

24.t012)

4734(3) 7189(2) 8368(2) 5922(I) 6547(6) 4458(4) 5406(4) 8689(4) 7601(4~ 3662(4) 3736(5) 2961(5) 2117(5) 2058(4) 2832(5) 4625(4) 5568(5) 5630(6) 5837~5) 5993q5) 5917~5) 5701q4) 9472q5)

10323q4) 11050q5) 10961q5) 10111(5) 9346(5) 8404(5) 7470(5) 73~6(0)

7070(5) 7|67(~) 735~(4)

20(I) 21(I) 18(I) 18(I) 20(I) 32(I) 43(I) 37(I) 44(I) 34(I) 35(I) 46(I) 46(I) 37(!) 34(I) 22(!) 36(i) 50(2) 48(1) 40(I) 35(I) 32(I) 31(I) 32(I) 39(!) 47(I) 47(I) 40(I) 26(I) 35(I) 47(2) 48( I ) 42(I)

31(I)

* U~. 4 is defined as o,te third of the trace of lhe onhogonali~cd U,~ lellSOr,

Comparison of the visible spectra shows that the same species is formed from Co:(DPhFL, solutions upon exposure to moisture but the rate of reaction is considerably slower for the latter, The reactions can b~ descril~d by the following equations:

2Co~(DPhF).~ + 1120: =* Co~O(DPhF)~ ( I )

2Co., (DPhF) a + H=O ~ Co~O( DPhF)~ + 2HDPhF (2)

In Eq. ( ! ) an oxidation takes place while hydrolysis is the process involved in Eq. (2). For synthetic purposes process ( ! ) gives the best results and the reaction is essentially quantitative, However, since the preparation of either Co~(DPhF),, n ~ 3 or 4, is not trivial, we also prepared 1 using a simpler synthetic method by adding a stoichiometric amount of LiOH Lo a mixture of CoCIz(HDPhF)2 and LiMe

4CoCI:(HDPhF) ~ + LiOH + 9LiMe

-~ Co~O(DPhF)~÷ 2LiDPhF+ 8LiCI +9CH4 (3)

F.A. Cotton el aL / hu)rganica Chimica Acta 266 ~ 1997) 91-102 97

Table 5 Atomic coordinates (× I(P~ ,'rod equivalent isotropic displacement parameters ( ~-" x ! 0 ~ ) |'or F%O( DPhF), ( IV. I .SC~Hs )

X y Z U,,q =

Fe(1) F¢12) F¢(3) F¢14) O(I) Nil) N(2) N(3) N(4) N(5) N(6) N(7) N(8) N(9) N(10) N(II) N(12) C(1) C(2) C(3) C(4) C(5) C(6) C(II) C(12) C(13) C(14) C(15) C(16) C(21) C122) C123) C(~4) C{2~) C12~) C(31) C132) C(33) C(34) C(35) C(36) C141) C(42) C(43) C144) C(45) C(46) C(51) C(52) C(53) C(54) C(55) C156) C(61) C(62) C(63) C(64) C165) C(66) C(71)

7444(!) 6247(1) 8859(!) 7499(I) 7519(2) 6204(2) 5179(2) 7033(2) 6576(2) 8943(2) 9366(2) 5784(2) 5975(2) 8624(2) 8084(2) 9843(2) 8628(2) 5314(3) 6772(2) 9509(3) 5513(3) 8437(3) 9570(3) 6213(3) 6899(3) 6929(3) 6271(3) 5595(3) 5565(3) 4253(3) 3759(3) 2911~ 4 ) ~516q ,I) ~00S, ,1 ) ]87X~,I) 7250~2) 7856~3) 8050q3) 7659~3) 7076~3) 6870t3) 625613) 6833~3) 6474(4) 5553(4) 4976(4) 5336(3) 9263(2) 9275(3) 9543(3) 9818(3) 9809(3) 9531(3) 9906(3) 9369(3) 9863(4)

10878(4) 1141914) 10931(3) 5526(3)

1732(i) 3632(1) 2472(I) 2278(!) 2534(2) 1537(2) 3201(2) 2505(2) 4025(2)

816(2) 2086(2) 4327(2) 2881(2) 3636(2) 3009(2) 129812) 906(2)

2299(3) 3442(3) 121913) 3836~3) 3592~3) 71413) 62813) 18913)

107913) 1162q3) 35713) 540q3)

39064 3 ) 48()3q 3) 55()9~ 3 ) 534114) ,t456(4) 37461~) 1958(2) 2038(3) 147613) 826(3) 735(3)

1290(3) 5028(2) 5463(3) 6459(3) 6990(3) 6557(3) 5574(3) - 180(2) ~475(3)

= 1443(3) =2105(3) -1812(3)

- 851(3) 2~04(3) 334113) 3782(3) 3402(4) 2582(4) 2132(3) 5303(3)

1823(I) 25(1) 2278(!) 28(1) 2488(1) 28(1) 3552(1) 26(1) 2527(!) 26(1) 2174(2) 30(!) 2068(2) 31(!) 872(I) 28(I)

1274(2) 29(I) 1621(2) 29(I) 1470(2) 28(I) 3208(2) 29(I) 3788(2) 29(I) 3040(2) 3411) 4058(2) 3211) 3086(2) 3411) 3670(2) 2811) 2126(2) 32(I) 763(2) 2911) 1324(2) 29(I) 3714(2) 3111) 3732(2) 3311) 3496(2) 30(I) 2388(2) 3011) 2072(2) 3911) 2268(3) 5811) 2783(3) 6311) 311113) 54(I) 291912) 3811) 178712) 3911) 2073(3) 5311) 1768(3) 72(2) 110813) ?7(2) 910(3) 8l(2)

1201(2) 5911) 267(2) 2911) 299(2) 37(I) 868(2) 4611)

=875(2) 4911) = 312(2) 4811) 2~9(2) 3411) 108012) 3011) 123712) 4311) 1097(3) 6311) 81013) 72(2) 662(3) 68(2) 788(2) 50(I)

1502(2) 2811) 844(2) 36(!) 755(2) 45(I)

1327(2) 49(i) 1986(2) 47(I) 2080(2) 37(I) 1032(2) 32(!) 612(2) 39(!) 188(2) 55(I) 182(3) 68(I) 598(3) 78(2)

1025(2) 52(i) 3328(2) 33(I)

(cwat#med)

Table 5 (continued)

X y ,7 Uo 4 a

C(72) 5596(3) 5569(3) C(73) 536414) 6522(3) C(74) 5062(4) 7215(3) C(75) 5Oi3(3) 6947~3) C(76) 5234(3) 6003(3) C(81) 5426(3) 2409(3) C(82) 4420(3) 2717(3) C(83) 3906(3) 2245(3) C(84) 4397(3) 1455(3) C(85) 5402(3) 1135(3) C(86) 5923(3) 1608(3) C(91) 8727(3) 4463(3) C(92) 8105(4) 5369(3) C(93) 8209(5) 6167(4) C(94) 8895(5) 6066(4) C(95) 9510(4) 5172(4) C(96) 9426(3) 4367(3) C(IOI) 8180(3) 2850(3) C(102) 9096(3) 2565(3) C(i03) 9194(4) 2375(4) C(104) 8390(4) 2449(4) C(105) 7476(4) 2717(4) C(106) 7377(3) 2914(3) C(IIi) 10884(3) 988(3) C(112) 11538(3) 46(4) C(I13) 12560(4) - 213(5) C(114) 12912(4) 489(8) C(115) 12261(5) 1400(6) C(ll6) 11255(3) 1666(4) C(121) 8464(2) 192(2) C(122) 8648(3) 89(3) C(123) 8423(3) =548(4) C(124) 802113) -1089(3) C(125) 783113) = 980(3) C(126) 8050(3) -334(3) C(IS) 1286115) 4046113) C(2S) 972(7) 3901110) C(3S) 1201118) 4213117) C(4S) 1448(16) 4870(21) C(5S) 2020116) 4908(17) C(6S) 1951(9) 461~(10) C17S) 1315118) 3710113) C(8S) 14948117) =24(19) C(9S) 14010(13) 1123113) C(10S) 14773110) 322111) C(IIS) 14273(8) 940(8) C(12S) 14469(6) 58117)

3992(2) 4085(3) 3536(3) 2S79(3) 2765(2) 4149(2) 4038(2) 4395(3) 4851(3) 4955(2) 4611(2) 2738(2) 2961(3) 2662(4) 2125(4) 1888(3) 2194(2) 4807(2) 5103(2) 5824(2) 6259(2) 5964(2) 5248(2) 2943(2) 2795(2) 2673(3) 2681(3) 2806(3) 2936(2) 4123(2) 4837,2) 5273q2) 500512) 430412) 3857i2) 4807t9) 4223(I) 3%0115) ~559(25) 3900(25) 4058(13) 5420(13) =935111)

5112) 370(8) 837(9)

=410(6)

43(I) 56(!) 60(1) 54{1) 43(1) 31(1) 42(!) 55(i) 56(I) 49(I) 37(1) 37(!) 57(1) 87(2) 89(2) 67(I) 47(I) 34(i) 46(1) 62(I) 64(I) 63(!) 48(I) 40(1) 58(!) 88(2)

108(3) 90(2) 62(!) 30(!) 44(I) 58(I) 54(I) 49(I) 37(I)

241(12) 154(5) 266( ! I ) 332(20) 352(26) 214(11) 3~(15) 12i(8) 109(5) 72(3)

153(4) 10112)

"U,.,, is defined as one third of t11¢ trace of the orthogonalizcd U u tensor,

Compound I is relatively stable in air both in solution and in the solid state; it decomposes slowly to produce a brownish solid.

Hydrolysis also explains the process that leads to the fi)r- mation of Zn40(DPhF)c,, which forms upon exposure to air of toluene solutions of Zn:(DPhF)4, made by reacting ZnCI2(HDPhF): with methyilithium, as follows:

2ZnCI: (HDPhF): + 4LiMe toluene

Zn2(DPhF)4 + 4CH4 + 4LiC! (4)

9~ F.A. Cotton et al. / lnorganica Chimica Acta 266 (1997) 91-102

Table 6 S~le~.~d atom ~pafallom (]k) and bond angles (o) for Co40(DPhFh, and Zn~O(DPhF)~

M=Co M=Zn M=Co M=Zn

M( I )...M(2) 3.141 (2) 3.122( I ) M(3)-N(I0) 2.017(5) 2.028(5) M( I )...M(3) 3.015 (2) 3.153( I ) M (3)-N( 11 ) 2.020(6) 2.031 (4) M{ I )...M(4) 3.147(2) 3.1272(9) M(4)-N (2) 2.060(6) 2,027(5) M(2)...M(3) 3.227(2) 3.1278(9) M(4)-N(8) 2.039(6) 2.029(5) M(2)...M(4) 3.184(2) 3.1554(9) M(4)-N(12) 2.043(6) 2.040(4) M( 3).. oM(4) 3.128( I ) 3.122( I ) N( 1 )-42( I ) 1.310(9) 1.318(7) M(2)-4:)( I ) 1.920(4) i.927(3) N(2)-C( I ) !.340(9) i.325(7) M(3)-O( I ) 1.925(4) 1.919(3) N(3)=C(2) 1.322(8) 1.324(7) M( 4)~4)( I ) 1.929(4) 1.920(3) N(4)-C(2) 1.335(9 ) 1.324(7) M( 1 b4)( I ) 1.925t 5) 1.912(4) N(5 )-C(3) 1.306(8) 1.318(8) M( I )=N( I ) 2.033(5) 2.030(5) N(6)-C( 3 ) 1.332(8) 1,321 (8) M(I)~N(3) 2.022(5) 2.023(5) N(7)--C(4) 1.326(9) 1.333(7) M(I)=N(5) 2,003(6) 2.045(4) N(8)~C(4) 1.317(8) 1,338(7) M(2)=N(6) 2.(}08(6) 2,037(4) N(9)--C(5) 1,322(8) 1.312(7) M(2)~N(7) 2.002(6) 2,028(5) N(10)-C(5) 1.317(8) 1.333(7) M(2)=N(9) 2.001 (5) 2.024(5) N( 1 I)-42(6) 1.314(8) 1.331(8) M(3).-N(4) 2.044(5) 2,029(5 ) N(12)-42(6) 1.323(8) 1.310(8)

O( I )=M( I )~N( I ) 104.7(2) 105.0(2) M( I )-43( I )-M(2) 109.6(2) 108.8(2) O( I )=M( I )=N(3) I07.4(2 ) ~0 ~t 0(2) M( I )-O( I )-M(3) 103.1 (2) I I0.8(2) O( I )=M( 1 )=N(5 ) I07,8(2) 105,2(2) M( I )-4)( I )-M(4) 109.5(2) 109.4(2) N( I )=M( I )=N(3) 112,6(2) I 13,2(2) M(2)-O( I )-M(3) 114.1 (2) 108.8(2) N( I )=M( I )~N(S) I05,5(2) 113,7(2) M(2)-O( I )~M(4) I 11.7(2) 110.2(2) N(3) °M( ! )=N(5) 118,1 (2) 114,4(2) M(3)=O( I )-M(4) 108,5(2) 108.9(2) O( I ) oM(2)=N(6) 102,9(2) I05,0(2 ) C( I )-N( 1 )-M( I ) 119.6(4) 117.6(4) O( I )=M(2)=N(7) 107,0(2) 104.0(2) C( I )~N(2)-M(4) 113.7(4) 117.6(4) O( 1 )=M(2)=N(9) !04,0(2) 105,8(2) C(2)=N( 3)=M( ! ) 116,2(5) 118,1(4) N(6)=M(2)=N(7) I09,0(2) 114,$(2) C(2 )=N(4)=M(3) 115.5(4) 117.0(4) N(6)=M(2)=N(9) 117,6(2) 113,0(2) C( 3)=N(5)~M( I ) 125,0(5 ) 115.4(4) N(7)=M(2)=N(9) l IS,0(2) 113,S(2) C( 3)=N(6)=M(2) 125,7(4) 116,5(4) O( I )=M(3)=N(4) 109, I (2) 104,6(2) C(4)=N( 7)=M(2) 125,6(5) 118A(,l) 0(1 )=M( 3)=N(I0) I0~,6(2 ) I05,2(2) C(4)=N(g)=M(4) 129,2(5) 116,7(4) O( ! )=M( 3)=N( I I ) 103 3(2) 104,9( 2 ) C( S )=N( 0 )=M( 2 ) 127 8( ~ ) I I ?,3(4 ) N( 10):M( 3 )=N(4) 103,6( 2 ) I 13,7( 2 ) C( S )=N( I0 ) =M( 3 ) 128,7( 4 ) I 17,2(4 ) N( II )=M(3)=N(4) I I 1,0(2) 113,3(2) C(6) :N( 11 )=M(J) I I?,0(S) 1100(4) N( 10):-M(3):-N( I1 ) 122,6(2) 1139(~) C(6} -N(12)-M(4) i 17,8(4) 117,3(~t) O( 1 )=M(4)=N(2) 103,9(2) 10~,~(2) N( ! )--C( I )=N(2) 1~9(6 ) 12,1:1(~) O( 1 )=M(4)=N(8) [0~,~(: ) 104,6( 2 ) N( .t)-[?.( 2)-N(4 ) 121.4(0) I ~.1.9(~ ) O( i )=M( 4)=N(12) IES, I (2) I04,5(~) N( $ )-~( 3 )=N(6 ) 1263(6) i24 ?(5) N(i~)=M(4):N(2) 124,0(2) 11£3(2) N(8)=C(4)=N(?) 127,6(7) 122,?(~) N(12)=-M(4~=N(2) 108,2(2) 113,3(2) N(10)=C(S)=N(9) I~.~ S(6) 123.9(5) N(8)o.M(4)=N(12) 108,6(2) 114.0(2) N( I I )~C(6)~N(12) 121 .$(?) 123,1 (.S)

2Zn: (DPhF L, + H:O ~ gn~O(DPhF)~ + 2HDPhF (5)

Support for Eq, (4) is provided by ~H NMR data, 'rh¢ hydrogen atom of the methinc proton in Zaa(DPhF)4 at 8,20 ppm quickly disappears upon addition of one equivalent of water and the data clearly show the presence of both com- pounds, It and HDPhE in a I to 2 ratio, Two n,~w singl~ts appear at a 8 value of 8,05 ppm (for l) and 7.87 ppm (for HDPhF), The signal corresponding to the neutral (proton° ated) ligand does not appear after the solid has heen washed with warm hexanes,

As indicated e~rlier, the. reactions of the ir~m ~nalogs are more complex, The easy access to higher oxidation states promotes the formation of soluble ~nd insolubie oxo. and hydroxoqron compounds, We have already show~ that in the presence of ~ir, iro~ solutions which canton lithium formam- idinate speci¢~ are readily oxidized to give intensely colored solutions conlaining an unusual iron-oxo tetranuclear species,

namely, Li:(HDPhF):Fe~O~(DPhF)~. which has an eight° mombered ring of alternating iron and oxygen atoms [21.

Under controlled conditions, exposu~ of air to solutions of the very air-s~nsitiv~ F~2(DPhF)~ compound gives less intensely colored solutions from which Fe~O(DPhF)~, crys- tals can be isolated according to

2Fe.~(DPhF).~ + I/20~ ~ Fe~O(DPhF)~ (6)

We have also prepared IV from a procedure analogous to that :dlown in Eq, (3) using F~Ia(HDPhF) ~ as slardng mate- rial. A similar product is isolated from the rcaclion of FeCi~(HDBiPhF)~ and LiMe in the presence of a small amount of moisture:

2F¢Ci~(HDBiPhF)a + H20 + 8LiMe

Fo,~O(DBiPhF)¢, + 2HDBiPhF + 8CH4 + 8LiCI (7)

F.A. Cotton et al. I hmrga.ica Chimi('a Acre 266 ¢ 19971 91-102 99

Table 7 Selected atom separations (A) and bond angles (°) for Mn.=O(DPhFb,. Atoms Mn( ! ) and Mat2) represent one of the two disordered systems, Mn(3) and Mn(4) 1he other

Mn( I )...Mn(21 3.235(3) Mn(2)-N(3)' 2.089(51 Mn(2).-.Mn(2)' 3.264(31 Mn(2)-N(4)-' 2.146(4) Mn(3), . -Mn(4) 3,225(2) Mn(3)-N(3) 2.246(5) Mn(4),- ,Mn(4) = 3,262(2) Mn(4)-N ( 1 )~ 2.112(4) Mn( 1 ) -O 1,942(7) Mn(4)-N(2) ~- 2,145(4) Mn(2) -O 2.006(3) Mn(4)-N(4) 2.256(5) Mn(3) -O 1.949(7) N ( I ) - C ( I ) 1,305(6) Mn(4)-O 1.999(2) N (2) -C( ! ) 1,301 (6) Mn( I )-N( I ) 2,358(5) N(3) -C(2) 1,325(6) Mn(2) -N(2) 2.386(5) N(4 ) -C(2 ) 1,304(6)

N(I)-'LMn( I ) - N ( I ) 118.46(5) N(2):-Mn(4)-N(4) 119.3(2) O=Mn( I )~N(I) 97.2(I) Mn( l ) -O-Mn(2) i =u.O(2) O-Mn(2)=N(2) 97.6121 Mn(2)~'=O=Mn(2) 108.9(2) O-Mn(2)-N(3) ' 102,4(21 Mn(3)~O=Mn(4) 109.6(2) O-Mn(2)-N(4) ~ 102,8(21 Mn(4) '-O-Mn(4) 109.4(21 N(3) LMn(2)-N(4): ' 117.7(2) C( i )-N{ l )-Mn(4)-" 122.7(31 N(3)LMn(2) -N(2) 111.9(21 C ( I ) - N ( i ) - M n ( I ) 110.5(3) N(4): '-Mn(2)-N(2) 119.8(2) C( I ) -NI2)=Mn(4) ' 119.7(3) O-Mn(3)-N(3) 98,8( I ) C( ! )=N(2)-Mn(2) 104.4(3) N(3)LMn(3)=N(3) 117,70(7) C(2)=N(3)=Mn(2) z !19.0(41 O-Mn(4)-N( I )' 103.8(21 C(2)-N(3)=Mn(3) 113,4(3) O=Mn(,I)=N (21" 106!( ! ) C(2)~Nt4)=M,(2) t ! 18,0(3) N( I ) LMn(4)~N(2) ~' 116.3(21 C(2)=N(4)~Mn(4) 109,0(31 O-Mn(4)=N(,I) 99.2(2) N(2)=C( I )-N( I ) 122.7(5) N( I ) '=Mn(4)=N(4) 109.2(2) N(4)=C(2)=N(3) 120,9(51

Synlllielry trallsfornlations llsed to generate equivalent alotns: s =y. I -o= v~ I. :; ~ ~x +y + I,=X, ;'.

Further reaction el' the iron complexes with oxygen gives the ¢hm'acleristic burgundy color of the oxidized material which quickly gives rise to intractable tan solids upon exposure to IIIOIV il if,

The |'eaclivily of mangm~es¢ compouml:; is similar to thai o1" the il'On cL.nl-~!cxes. A h.°L~e illllll |l~r t)l' i)gl)~ lllld hyth'oxo- manganese species are known in various oxidation states, but carcthl hydrolysis of MIb(DPhF)4 provides an almost col° orless divalent oxooccnlcrcd letramanganese cotnpound according to

2Mn:( DPhF),~ + ioi~O =} Mn40(DPhF). + 2HDPhF (8)

This compound is very sensitive to air and decomposes quickly to give a dark (almost black) ivsolublc matcrial.

3.2. Str.ctural co.sidera,ions

The structure of both ! and II, shown in Fig. I, is similar to that of Ihe basic zinc or beryllium carboxylates. It consists of an oxygen atom at the center of a tetrahedron of metal atoms. Each metal atom is tetrahedrally coordinated to the central oxygen atom and to three nitrogen atoms from three independent DPhF groups. Each iigand forms a bridge to each of the other three metal atoms along the edges of the [M401 f'' unit as seen in Fig. 2. The tetrahedron o1" metal atoms is quite regular for the Zn compound, for which the non-bonded Zn...Zn distances vary from 3.122(I) to

Table 8 Selected atom separations (A) and bond angles ( ° ) for Fe.=O( DPhr: ),~

Fe(I)...Fe(2) 2,857(!) Fe(3)-N(9) Fe( I )--.Fe(3) 3.197(I) Fe(3)-N(! I ) Fe( I ) , , . Fe (4 ) 3.489( 1 ) F e ( 4 ) - N (8 ) Fe(2)--.Fe(3) 3519( i ) Fe(4)-N(10) Fe(2) . - -Fe(4) 3.160(2) Fe (4)-N (12) Fe(3)-.-Fe(4) 2.850( I ) N( ! )-C( ! ) F e ( I ) - O ( ! ) i.953(2) N ( 2 ) - C ( I ) Fe(2)-O( ! ) i.952(21 N(3) -C(2) Fe( 3)-O( ! ) !.953(2) N (4) -C(2) Fe(4)-O( ! ) !.955(21 N(5) -C(3) F e ( I ) - N ( I ) 2.059(3) N(6) -C(3) Fe ( I ) -N(3) 2.048(3) N(7)--C(4) Fe( I ) -N(5) 2.070(3) N(8) -C(4) Fe(2)-N(2) 2.062(3) N(9) -C(5) Fet2)=N(4) 2.044(3) N(101=C(5) Fe(2)=N(7) 2.067(3) N ( I I ) - C ( 6 ) Fe(3)-N(6) 2.065(3) N(12)=C(6)

O( I ) -Fe( I ) - N ( i ) O( I ) -Fe( I ) = N ( 3 ) O( I ) -Fe( ! ) - N ( 5 ) O( I )-Fe(2~=N(2) O( 1 )-Fe(2)-N(4) O( I )-Fe(2)=N(7 ~, O( I 1 ~Fc(3) =Nt6) O( I )=Fe(3)=N(9) O( I ) - F e ( 3 ) = N ( I I ) O( I )~ F e ( 4 ) - N ( 8 ) O( I )=Fc(4)-N(I0) O( I )-Fe(4 )-oN(12) N( I )=Fc( I )-N(3) N(i)=Fe(I)=N(5) N(3) 4~e( I)~N(51 N(21- Fc(2)~N(4) N(21- Fe(2)-N(7) N(,I )-Fe( 2 )--N( 7) N16).d:e(3)=N(9) N((~) I:e(~) N ( I I ) N(0) Fc(~) N ( I I ) N(8)=Fe(4)=N(I0) N(8)=Ft~(4)=N(12) N(I(I).°R~'(4) =N(12)

102.7( I ) 110,7( I ) 102.3( I ) 1119(I) I01,5( I ) 102.5( I ) 102,5( I ) 101,9( I ) 111,8(I) 101,2( ) 112.4( ) 101,7( ) 103.8( ) 134,6( ) 102.0( ) 0~kS( )

106,9( ) I :~4 ( l ( ) 133,9( ) 102 2( I I04.2( ) 107,7( ) 133.3( ) 100,2( )

2.057( 3 ) 2.058( 31 2.064(3) 2.051(31 2.044(3) i.327(51 !.319(51 !.326(41 1.317(41 !.327(51 1.321(51 1.325(51 !.325(51 !.328(51 1 326(5 ) !.323(51 1.321(41

Fe( I )-O( I )-Fe(2) 94.0( I ) Fe( I )-O( ! )-Fe(2) 109.9(I) Fe( 1 )-O( I )-Fe(4) 126.5( I ) Fe(2 )-O( I )-Fe(3) 128.0( i ) Fe(2)-O( ! )-Fe(4) 107.9( I ) Fe( 3)=O( i )-Fe(4) 93.6( I ) C( I )=N(I )=Fe( I ) !17.4(21 C( I )-N(2)-Fe(2) 124.5(2) C(2)=N(3)=Fe( I ) 124.6(21 C(2)=N(4),°Fe(2~ 120.3(2) C(3)-N(5)-Fe( I ) 116,7(21 C(3)-N(6) Fel3) 116.2(2) C(4)=N(7)=Fe(2) 112.9(2) C(4)-N(8)~Fe(4) 114.6(2) C(5)~N(9)-Fe(3) 1185,21 C(5)--N(10)=Fc(4) 124 2(2) C(e,)~ N( I I ).-F~,(~) 12~ ~112) ('{61 N( 12)--Fc(41 121 2(21 N(2) ,C(1)-N(I ) 124 I(~)

N(e,) C('~) N(5) 1220(~) N(' /)=CI4)-N(8) 121K('~) N' 10)=C(5) ~N(O) 12~,7(~) N( 12)~ C(6 ) -N( I I ) 1240(~)

3. ! 53( ! ) ,~, but it is slightly more distorted in the Co comt~le x (the Co...Co distances vary from 3.015 ( 2 ) to 3,227(2) ,~ ), However, those distances are about the same as those tk~und in the carboxylate analogs I ! 21. The M=O distances of 1.92= !,93 .,~ for I and i,9111,93/~ for 11, respectively, are also those expected for this type of metal core, as are the Iv-N distances. The M=N distances are regular, but the Co=N di,~- tances are ~ 0.08/~ longer than those tbund in the dinuclcar species Co2(DPhF),,, n = 3 or 4. It is worth noting the high degree of flexibility provided by the formamidinate ligaads. In many dinuclear complexes the ring is essentially planar, but in compounds in which there is a long M...M distance the I~-ZNLCL~NL~M distortion from planarity is very signifi- cant. As can be seen in Fig. 2, for the zinc compound lhere are two planar moieties (gn( I ), N(3) , C(2) , N(4), Zn(3) and Zn(2), N(71, C(41, N(8) , Zn(4) ) and four non° planar rings distributed in a regular manner about the metal atoms.

100 F.A Cotton et a l . I Inorganica Chimica Acta 266 (1997) 91-I02

CI92)

C[1111

C|25l("'~ Nr C(61l

1041

C:1531 ..... ~/ ' Cl33)

Fig I. Therm$ ellipsoid plot of the Zn~O(DPhF),~ molecule. The atom bbeling scheme is the same in the Co analog, Atom,~ are represented by their 40% probability ellipsoids, Numhe=mg for phenyl carhon atoms pro- ceed~ logically from the numbers shown.

Fig, 2. A d¢~wing of the core in compounds I showing the ~etral~dral arxa|Igement of the me[~l ~toms about ~be centr~l oxygen ~nd th~ ~gul~r distribution of DPhF llgands.

Thc conformation is different in the cobalt compound. As shown in Fig. 3, there are thre~ bridges ofeach type present. In spite of the relative similarity in the metal~metal distances in I and II the distribution about the Co atoms is not e0gul~, Atom Co(2) is connected to planar bridges exclusively while each of the remaining Co atoms connect to a planet and two twisted Co=N=C=N=Co groups,

The structure of III is also similar to that of ! and il with the additional complication of crystaUogr~phic disorder of the metal atoms. There are two possible orientations of the

N(81

N(2)

N(5) ~ . . . . .

C15~ Fig. 3, A drawing of the co~ in com~und II showing the unsymmetrical distribution of the plan~ ~ d twisl~ Co=N~C=N=Co groups.

NI4~

Ft[~ 4 Keprc~cJ~lalhm of tltc di~(mie~' ~| Ih~ ¢olx, ol |h~ Mth~)(lTPhi~)~ molecule Oae Ot~Cnlati~ll t', t~p|~,~cnlcd by ~)lid bo.d~. |he olht~l by oI~. bond~,

tetcahedton foiTncd by the t~ur Mn atoms, The two orient;l- tions arc related by a pseudo-inversion center Iocaled at the position of the oxygen atom as indicated in Fig. 4. The an- isotropic displacement parameters (ADPs) of the ligand atoms drawn in Fig. S show subtle but convincing evidence that the disorder is not limited simply to the occupation of two sets of sites for the manganese atoms. The ADPs of all of the ligated nitrogen atoms, as seen in visual inspection of their 'thermal dlipsoids', indicat,~" an unusual elongation that cannot reasonably b¢ atbibuted t~ thermal motion. There are two crystallographically independent formamidina|c ligands, with a total of four nitrogen atoms. Each nitrogen atom is bonded to one manganese atom of each of the two disordered congeners, and for every nitrogen atom the two congeneric Mn-N distances arc significantly difl~rcnt. The thermal ellip- soid in each case is elongated and tilted in such a fashion that the axis of largest principal displacement points roughly toward that manganese congener which is farther from the nitrogen atom under consideration. These two effects - - the

F A. Cemm eta/,/btergmffca Chimic~a Acta 266 ¢!997) 91-102 101

Ni2!

MnI4B)

"~ CI1)

MnI4AI Fig. 5. A drawing of a disordep~d Mn-N-C-N-Mn group in compound !!1 showing the elongated displacement ellipsoids of the nitrogen atoms.

significant difference between chemically equivalent dis- tances and the elongation of the displacement ellipsoids taken together indicate that the disorder that is evidenced principally by the presence of two different sets of sites for the manganese atoms, is also present in the ligands, but to a sufficiently lesser extent that the disordered atomic sites remain unresolved. It is proper, then, to regard all of the Ma- N distances derived from the crystal structure as 'apparent bond distances', as discussed in a different context by Stebler and Burgi [ 27 l, and not as values that have the sort of reli- ability normally associated with the results of diffraction analysis. As far as we know this is the first manganese com- pound which has a structure derived from the basic zinc or beryllium carboxylates.

Compound IV, whose structure is shown in Fig. ~, ~,',, an arrangement o1" Fe, O and N atoms which is only partly similar

~~ CI231

( ~ ~3et2~D

, \ q J b

"l )

C 1 1 1 2 ~ 9

Fig. 6. A plot and labeling scheme of the structure of Fe,sO( DI)hF),. Atoms are represented by their 50% probability ellipsoids. Numbering for phenyl carbon atoms proceeds logically from the numbers shown.

C141

CI5~ C(6~

NIS) _ F j ~ ~

C(II Fig. 7, A drawing o[ the core in compounds IV and V.

to that of the Co, Mn and Zn compound described above. There is an oxygen atom in the center of a highly distorted tetrahedron of Fe atoms. As in I, 11 and Ill each of the metal atoms is bonded to the oxygen and to three nitrogen atoms. However, the formamidinate bridges are not regularly dis- tributed; as shown in Fig. 7. Two of the edges of the tetra- he&on of metal atoms are 4~ubly-bridged, two are singly-bridged and the other two are non-bridged. The pattern of non-bonded Fe-Fe distances clearly shows the effect of such distribution. There are two short distances ( ~ 2.85,3,), two intermediate ( ~ 3.17 A) and a pair of longer distances ( ~ 3.50/~). Tile bonded Feo43 and Fe-N distances are quite rcguh,' and show only minor deviations from thc average of 1.95 and 2.05 /~, respectively. The overall idealized sym° merry of the molecule is C2. Tile structure of compound V is very similar to that found in IV. As far as we know these are the first oxo compounds of iron in which the (/x4°OFe4) "' core has been found.

For IV, the room temperature magnetic susceptibility of 6.75 BM (3.38 BM per iron containing unit) is well below the typical range of 5.0=5.6 BM per iron unit found in mononuclear tetrahedral Fe(ll) compounds. This is indica° live of possible coupling between the electrons. The situation is similar in the Co analog. Unfortunately the lack of variable temperature magnetic susceptibility instruments in our labo- ratory impeded further magnetic studies.

4. C o n c l u s i o n s

Hydrolysis of dinuclear tbrmamidinate compounds of Zn, Co, Mn and Fe produces oxo-centered tetranuclear coin° plexes of formula M40(formamidinate)6. Their structures are related to that of basic beryllium acetate, Be40(OAc)~,. However, there are small but significant structural differences in the new family of compounds. The zinc complex is regular. Each metal atom is bridged by three formamidinate groups which form two twisted M-N-C-N-M moieties and a planar

102 F.A. Cotton et al. I lnorganiea Chimica Acta 266 (1997) 91-102

., " ~ ".

(a)

F

(b) Fig. 8. A schematic representation of the cores in (a) M40(DPhF)s, M ~, Mn, Co and Zn; (b) the iron analog. Note the differences in the distri- bution of the DPhF g~XOUl~. Dotted lines indicate singly-bridged tetrahedron edg,~, halched line~ re l iant doubly.bridged edges and wavy lines are d~wn for non=bridged edges.

one. The cobalt complex is slightly more distorted with three planar and three distorted M-N=C-N-M groups of atoms. All planar groups are bonded to the same cobalt atom. The manganese complex is qualitatively similar but there exists a crystallographic disorder in which two independent Mn~O 6 + totrahedra appear to be intertwined. The iron complexes differ even more. Two F~Fe edges of the tetrahedron are doubly bridged, another two opposite edges are singly bridged and the remaining two edges are unbridged. The differences in the ligand distribution is shown schematically in Fig. 8.

$. Supplementary material

Tables of crystallographic data including bond lengths, bond angles and anisotropic displacement parameters (70 pages) are available t~om author F.A.C. on request.

Acknowledgements

We ate grateful to the Vicerrectoffa de [nvestigaci6n U.C.R. (Project 115-8%$16) and the Department of Chem- istry for support of work at the University of Costa Rica, the National Science Foundation for support of work at Texas A&M University and the Comisi6n lnt~.rministc.,qal de Cien- ciay Tecnologfa (Spain) (PlDjlect PB95-0792) for support of work at the Uni~rsity of Zaragoza

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