Supporting Information

© Wiley-VCH 2007

69451 Weinheim, Germany

10a-Aza-10b-Borapyrenes: Heterocyclic Analogs of Pyrene with Internalized BN

Moieties

Michael J.D. Bosdet, Warren E. Piers,* Ted S. Sorensen and Masood Parvez

† Department of Chemistry, University of Calgary, 2500 University Drive N.W.Calgary, Alberta, Canada, T2N 1N4

e-mail: wpiers@ucalgary.cahttp://www.chem.ucalgary.ca/groups/wpiers

Contents

Complete Experimental Procedures and Product Characterization Data.Table S1. Calculated NICS values for 5a-H and pyrene.Table S2. Experimental and Calculated Bond Lengths of 5b-iPr used for NICSComputationsFigure S1. Cyclic voltammogram of 5a-H.Figure S2. EPR spectra of [5a-H]·-[Li]+.

Figure S3. (a) Spin density map and (b) SOMO orbital picture of 5a-H.Figure S4. Emission spectra of 5a-H at various concentrations.

Figure S5. Excitation spectrum of a single crystal of 5c-iPr.

S 2

General Procedures. All operations were performed under a purified argon atmosphere

using glovebox or vacuum line techniques. Toluene, hexane and THF solvents were

dried and purified by passing through activated alumina, and vacuum distilled from

Na/benzophenone. NEt3, CH2Cl2 and cyclohexane were dried over and distilled from

CaH2. Phenylacetylene was purchased from Aldrich and passed through a column of

alumina immediately prior to use. Trimethylsilylacetylene was purchased from Petra

Research, Inc. and distilled prior to use. Celite 545® was purchased from Fisher

Scientific and heated at 200 oC under high vacuum for 3 days prior to use. Neutral

alumina (63-200 µm, 70-230 Mesh ASTM)) was purchased from EM Science and heated

at 200 oC for 3 days under high vacuum prior to use. Silica gel column chromatography

was carried out on Geduran Silica 60 silica gel (particle size 40-63 µm). Lithium metal,

2,6-dibromopyridine, CuI, and Pd(PPh3)4 were purchased from Aldrich and used as

received. 1-hexyne was purchased from Acros and used as received. PtCl2 was

purchased from Alfa Aesar and used as received. 1-chloro-2-(trimethylsilyl)-4-

isopropylboracyclohexa-2,5-diene was prepared as previously reported.[1] Compound 2a

was synthesized according to literature precedent,[2] with the solid product sublimed

twice under dynamic vacuum prior to use. Pyridines 2 b and 2c were obtained via

Sonogashira coupling employing 2,6-dibromopyridine, Pd(PPh3)4 (4 mol %), CuII (8 mol

%), and the corresponding terminal alkyne (2.1 equivalents) in NEt3 solvent, followed by

removal of the solvent in vacuo, extraction of the product into Et2O, and column

chromatography through silica.

All NMR spectra were recorded in dry, oxygen-free CD2Cl2, C6D6, toluene-d8 or THF-d8

on a Bruker DRX-400 MHz spectrometer (operating at 400 MHz (1H), 155 MHz (7Li),

128 MHz (11B), 100 MHz (13C) or 149 MHz (119Sn)) at 25 °C unless otherwise specified.

Chemical shifts were reported relative to SiMe4 (1H and 13C), LiCl (7Li), BF3•OEt2 (

11B),

or SnMe4 (119Sn) standards. Where required, 1H and 13C peak assignments were made

using 1H-1H COSY or 1H-13C HMQC 2D spectra. Electrochemical studies were

performed on an EG&G model 283 potentiostat with a three-electrode cell: platinum wire

auxiliary electrode, silver wire pseudo-reference electrode and a platinum disc working

S 3

electrode. Solutions were comprised of 1 mM test compound and 0.1 M [nBu4N][PF6] as

the supporting electrolyte in 5 mL of dry, deoxygenated solvent. All E1/2 values were

referenced internally to Cp2Fe (E1/2 = 0.54 V in THF (vs. SCE)). High-resolution mass

spectra were obtained on a Kratos MS-80 spectrometer operating in electron impact (EI)

mode. Fluorescence spectra were obtained on a Cary Eclipse spectrophotometer with

excitation and emission set to 2.5 nm bandpass, and UV-visible spectra were obtained on

a Cary 100 Bio spectrophotometer operating in double-beam mode. Fluorescence

quantum yield values were reported relative to 9,10-diphenylanthracene in cyclohexane

(φf = 0.90) after acceptable cross-calibration values were obtained with pyrene in

cyclohexane (φf = 0.65). Single crystal fluorescence was obtained using a drawn pyrex

strand as the crystal support, with an excitation wavelength of 330 nm and excitation and

emission bandwidths of 2.5 and 10 nm, respectively. For these experiments, the detector

power was increased to 1000 V. Fluorescence lifetime experiments were performed on a

Jobin Yvon Fluorolog Tau-3 lifetime system spectrophotometer using Ludox solution

(aqueous suspension of colloidal silica with zero lifetime) as a light scattering standard

and a 450 nm cut-on filter. The lifetime experiments were performed at an excitation

wavelength of 330 nm (unless otherwise specified), with interleave processing and

modeled using Δphase and Δmodulation values of 0.5 and 0.05, respectively. EPR spectra

were recorded on a Bruker EMX10/12 spectrometer at 25 °C after field calibration using

the dpph radical as an external standard. Thermogravimetric Analysis/Differential

Scanning Calorimetry (TGA/DSC) measurements were performed on a Netzsch STA

449C thermal analyzer under N2 at a heating rate of 5 °C/minute. Molecular orbital

computations were performed using Spartan at the B3LYP/6-311G* level. NICS

calculations were performed using Gaussian-03 with molecular structures optimized at

both the B3LYP/6-31G* and B3LYP/6-311+G** levels. The NICS probes were placed

at the geometric centers of the rings at distances of 0 or 1 Å using either the total

isotropic shielding value or just the zz component. X-ray crystallographic analyses were

performed on suitable crystals coated in Paratone oil and mounted on a Nonius Kappa

CCD diffractometer.

S 4

Synthesis of 5a-H. In an argon atmosphere, a solution of 1-H (90 mg, 0.49 mmol) in

toluene (1 mL) was added to a solution of 2a (62 mg, 0.49 mmol) in toluene (6 mL) and

stirred for 3 days. Volatiles were removed in vacuo and the brown solid subsequently

slurried in n-hexane (10 mL), sonicated for 30 minutes, and filtered through a swivel frit.

After several washes with n-hexane, the solvent was removed in vacuo, and the brown

solid was slurried in toluene and filtered through celite to afford an orange solution. To

this was added PtCl2 (3 mg, 11 µmol), and the mixture stirred for 16 hours at 95 oC.

After cooling and removing the toluene in vacuo, the brown solid was dissolved into

Et2O (10 mL) and filtered through neutral alumina. Yellow plates suitable for Xray

analysis were obtained by slow evaporation from this solution at 25 oC. Yield: 43 mg

(43%).

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7

8

NB

1H NMR (C6D6): δ 8.84 (d, 2H, 3JH,H 7.5 Hz, CH7), 8.78 (d, 2H, 3JH,H 8.5 Hz, CH5), 8.25

(t, 1H, 3JH,H 7.5 Hz, CH8), 7.62 (d, 4H, 3JH,H 8.3 Hz, CH2 + CH4), 7.45 (t, 1H, 3JH,H 7.5

Hz, CH1). 13C{1H} NMR (C6D6): δ 139.42 (s, C3), 138.92 (s, CH5), 133.04 (s, C6),

130.44 (s, CH7), 127.27 (s, CH1), 123.69 (s, C8), 120.42 (s, CH2), 117.35 (s, CH4).11B{1H} NMR (C6D6): δ 22.3 (broad s). UV-Vis (ε(104 L mol-1 cm-1)): λmax(CH2Cl2) =

443 (0.3), 321 (5.8), 285 (2.2) nm; λmax(n-hexane) = 479 (0.1), 447 (0.3), 322 (5.6), 286

(2.3) nm. Fluorescence (cyclohexane): λmax = 480, 493, 498, 506, 514 nm; φf = 0.15, τf =

70 ns (χ2 = 0.30). Cyclic Voltammetry (vs. SCE): E1/2(THF) = –1.98 V. HR-MS for

C14H10N11B (M+): 203.09063 (calculated); 203.09112 (found). TGA: Tonset = 101 oC,

T5% = 153 oC. M.P. = 138 oC (DSC).

S 5

Synthesis of [5a-H]·-[Li]+. A solution of 5a-H (20 mg, 98 µmol) in THF (2 mL) was

stirred in a 10 dram vial with a lithium mirror (1 mg, 0.14 mmol) for 1 day at 25 oC,

giving a deep purple solution. The solution was subsequently filtered and evaporated to

dryness in vacuo, giving a deep purple solid. EPR (THF): giso = 2.003 (broad). 7Li

NMR (THF-d8): δ 0.04 (broad s).

Synthesis of 5b-H. In an argon atmosphere, a solution of 2b (180 mg, 0.65 mmol) in

toluene (15 mL) was added dropwise to a solution of 1-H (119 mg, 0.65 mmol) in toluene

(5 mL), and the resulting solution stirred for 3 days. Volatiles were removed in vacuo,

after which n-hexane (5 mL) was added followed by sonication. The mixture was loaded

onto an Al2O3 column and eluted with Et2O. The solvent was removed in vacuo, and the

resulting orange oil was redissolved in 15 mL toluene and was stirred for 36 hours at 95oC with PtCl2 (2 mg, 8 µmol). The mixture was then dried in vacuo, redissolved in n-

hexane (10 mL), and loaded onto a column of neutral alumina. Elution with Et2O,

followed by slow evaporation from this solution gave 5b-H as orange needles. Yield:

155 mg (86%).

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8

910

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N

B

1H NMR (C6D6): δ 8.99 (d, 2 H, 3JH,H 8 Hz, CH7), 8.13 (t, 1H, 3JH,H 8 Hz, CH8) 7.87 (m,

4H, CH10), 7.82 (s, 2H, CH4), 7.75 (d, 2H, 3JH,H 8 Hz, CH2), 7.60 (t, 1H, 3JH,H 8 Hz,

CH1), 7.44 (t, 4H, 3JH,H 8 Hz, CH11), 7.36 (tt, 2H, 3JH,H 8, 4JH,H 1 Hz, CH12). 13C{1H}

NMR (C6D6): δ 151.22 (s, quaternary C), 142.03 (s, quaternary C), 139.28 (s,

quaternary C), 130.59 (s, CH10), 129.50 (s, CH7), 129.16 (s, CH11), ~128.9 (s, CH12),

127.84 (s, CH1), 123.78 (s, CH8), 120.46 (s, CH2), 117.74 (s, CH4). 11B{1H} NMR

(C6D6): δ 22.65 (broad s). UV-vis (ε(104 L mol-1 cm-1)): λmax(CH2Cl2) = 446 (0.10), 328

(9.7), 260 (3.3) nm; λmax(n-hexane) = 453 (0.13), 327 (9.7), 259 (3.4) nm. Fluorescence

(cyclohexane): λmax = 489, 522 nm, φf = 0.11, τf = 76 ns (χ2 = 2.05). HR-MS for

S 6

C29H24N11B (M+): 355.15323 (calculated), 355.15201 (found). Cyclic Voltammetry (vs.

SCE): E1/2(THF) = –1.85 V. TGA: Tonset = 132 oC, T5% = 263 oC. M.P. = 175 oC

(DSC).

Synthesis of 4b-iPr. In an argon atmosphere, a solution of 2b (35 mg, 0.13 mmol) in

toluene (4 mL) was added dropwise to a solution of 1-iPr (28 mg, 0.13 mmol) in toluene

(2 mL), and the resulting solution stirred for 48 hours. Volatiles were removed in vacuo

to give the product as a viscous orange oil. Yield: 42 mg (99 %).

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B 15

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1H NMR (C6D6): δ 9.41 (d, 1H, 3JH,H 12 Hz, CH11), 8.24 (dd, 1H, 3JH,H 12, 4JH,H 1.5 Hz,

CH10), 8.10 (d, 1H, 4JH,H 1.5 Hz, CH8), 7.68 (dt, 2 × 2H, 3JH,H 8, 4JH,H 1.5 Hz, CH13 +

CH20), 7.36 (t, 2H, 3JH,H 7 Hz, CH14), 7.27 (t, 1H, 3JH,H 8 Hz, CH15), 7.05 (m, 1 + 1 + 2H,

CH5 + CH22 + CH21), 6.98 (2 × d, 2H, 3JH,H 7 Hz, CH1 + CH3), 6.49 (t, 1H, 3JH,H 7 Hz,

CH2), 3.05 (sept, 1H, 3JH,H 7 Hz, -CHMe2), 1.36 (d, 6H, 3JH,H 7 Hz, -CHMe2). 13C{1H}

NMR (C6D6): δ 155.42 (s, C7), 142.92 (s, C16), 142.66 (s, C6), 142.39 (s, C4), 139.73 (s,

CH10), 132.32 (s, CH20), 131.12 (s, C12), 130.66 (s, CH13), 129.70 (s, CH22), 129.28 (s,

CH11), 128.79 (s, CH14), 128.47 (s, CH3), 128.28 (s, C15), 127.06 (s, CH2), 126.63 (s,

CH8), 125.38 (s, CH1), 123.48 (s, C19), 117.00 (s, CH5), 97.50 (s, C17), 90.71 (s, C18),

36.40 (s, -CHMe2), 24.98 (s, -CHMe2). 11B{1H} NMR (C6D6): δ 28.44 (broad s). UV-

Vis (ε(104 L mol-1 cm-1)): λmax(CH2Cl2) = 466 (0.8), 363 (1.0), 314 (2.7), 287 (2.5) nm;

λmax(n-hexane) = 460 (0.5), 361 (0.9), 315 (2.5), 285 (2.6) nm. Fluorescence

(cyclohexane): λmax = 499, 533 nm. HR-MS for C29H24N11B (M+): 397.20018

(calculated), 397.19754 (found). Cyclic Voltammetry (vs. SCE): E1/2(THF) = –1.77

(quasi-rev); Ered(THF) = –2.01 (irrev.); Eox(THF) = +1.03 (irrev.) V.

S 7

Synthesis of 5b-iPr. A mixture of 4b-iPr (200 mg, 0.58 mmol) in 25 mL toluene with

PtCl2 (9 mg, 34 µmol) was stirred for 24 hours at 90 oC. The mixture was then dried in

vacuo, redissolved in toluene (10 mL), and filtered through celite. Orange-brown crystals

were obtained from this solution after storing at –35 oC for 2 days. Yield: 198 mg (99%).1

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N

B

1H NMR (C6D6): δ 8.98 (s, 2 H, CH7), 7.91 (dd, 4H, 3JH,H 8, 4JH,H 1 Hz, CH10), 7.81 (s,

2H, CH4), 7.73 (d, 2H, 3JH,H 8 Hz, CH2), 7.55 (t, 1H, 3JH,H 8 Hz, CH1), 7.45 (t, 4H, 3JH,H 8

Hz, CH11), 7.34 (tt, 2H, 3JH,H 8, 4JH,H 1 Hz, CH12), 3.38 (sept, 1H, 3JH,H 7Hz, CHMe2),

1.43 (d, 6H, 3JH,H 7 Hz, CHMe2). 13C{1H} NMR (C6D6): δ 150.71 (s, C6), 144.31 (s,

quaternary C), 142.23 (s, quaternary C), 138.86 (s, quaternary C), 138.22 (s, quaternary

C), 130.64 (s, CH10), 129.66 (s, quaternary C), 129.20 (s, quaternary C), 128.89 (s,

CH11), 127.98 (s, quaternary C), 127.19 (s, quaternary C), 126.03 (s, quaternary C),

120.40 (s, CH2), 117.92 (s, CH4), 37.63 (s, CHMe2), 26.31 (s, CHMe2). 11B{1H} NMR

(C6D6): δ 23.36 (broad s). UV-vis (ε(104 L mol-1 cm-1)): λmax(CH2Cl2) = 483 (0.1), 453

(0.2), 332 (5.6), 261 (3.0) nm; λmax(n-hexane) = 492 (0.1), 461 (0.2), 330 (4.7), 259 (2.6)

nm. Fluorescence (cyclohexane): λmax = 498, 532 nm, φf = 0.11, τf = 53 ns (χ2 = 1.25).

HR-MS for C29H24N11B (M+): 397.20018 (calculated), 397.20055 (found). Cyclic

Voltammetry (vs. SCE): E1/2(THF) = –1.99 V. TGA: Tonset = 80 oC, T5% = 220 oC. M.P.

= 179 oC (DSC).

Synthesis of 4c-H. In an argon atmosphere, a solution of 1-H (77 mg, 418 µmol) in

toluene (2 mL) was added dropwise to a solution of 2c (100 mg, 418 µmol) in toluene (10

mL), and the resulting solution stirred for 5 days at 25 oC. Volatiles were removed in

vacuo to give a viscous brown oil, which was dissolved in n-hexane, loaded onto a

S 8

column of neutral alumina, and eluted with dichloromethane. Subsequent removal of

volatiles in vacuo gave 4c-H as a viscous orange-brown oil. Yield: 113 mg (86 %).

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NB

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1H NMR (C6D6): δ 9.36 (d, 1 H, 3JH,H 12 Hz, CH11), 8.34 (m, 1 H + 1 H, CH8 + CH9),

7.52 (dd, 1 H, 3JH,H 12 Hz, 5JH,H 2 Hz, CH10), 6.99 (m, 1 H + 1 H, CH1 + CH3), 6.89 (s, 1

H, CH5), 6.53 (dd, 1 H, 3JH,H 8 Hz, 3JH,H 7 Hz, CH2), 3.15 (t, 2 H, 3JH,H 8 Hz, CH13), 2.29

(t, 2 H, 3JH,H 7 Hz, CH19), 1.81 (m, 2 H, CH14), 1.50 (m, 2 H, CH20), 1.39 (m, 2 + 2 H,

CH15 + CH21), 0.91 (t, 3 H, 3JH,H 7 Hz, CH16), 0.83 (t, 3 H, 3JH,H 7 Hz, CH22). 13C{1H}

NMR (C6D6): δ 157.14 (s, C7), 144.18 (s, quaternary C), 138.64 (s, C9), 136.12 (s,

quaternary C), 132.42 (quaternary C), 129.36 (broad s, CH11), 127.78 (s, CH8), 127.22

(s, CH2), 125.64 (s, CH1/3), 124.65 (s, CH1/3), 122.47 (s, CH10), 115.44 (s, CH5), 99.90 (s,

C17/18), 81.95 (s, C17/18), 34.32 (s, CH14), 33.99 (s, CH13), 30.54 (s, CH20), 23.77 (s,

CH15/21), 22.78 (s, CH15/21), 20.36 (s, CH19), 14.59 (s, CH16), 14.08 (s, CH22). 11B{1H}

NMR (C6D6): δ 28.66 (broad s). UV-Vis (ε(104 L mol-1 cm-1)): λmax(CH2Cl2) = 456 (0.7),

341 (1.6), 320 (6.2), 288 (3.3) nm; λmax(n-hexane) = 445 (0.4), 345 (1.6), 321 (7.0), 288

(3.0) nm. Fluorescence (cyclohexane): λmax = 479, 512 nm, φ f = 0.06. Cyclic

Voltammetry (vs. SCE): Ered(THF) = –1.79 V; Eox(THF) = +1.06 V. HR-MS for

C22H26N11B (M+): 315.21583 (calculated), 315.21471 (found).

Synthesis of 4c-iPr. In an argon atmosphere, a solution of 1-iPr (494 mg, 2.18 mmol) in

toluene (5 mL) was added dropwise to a solution of 2c (522 mg, 2.18 mmol) in toluene

(20 mL), and the resulting solution stirred for 40 hours at 25 oC. Volatiles were removed

in vacuo to give a viscous brown oil, which was dissolved in n-hexane, loaded onto a

column of neutral alumina, and eluted with dichloromethane. Subsequent removal of

volatiles in vacuo gave 4c-iPr as a viscous orange-brown oil. Yield: 629 mg (81 %).

S 9

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1H NMR (C6D6): δ 9.28 (d, 1 H, 3JH,H 12 Hz, CH11), 8.27 (dd, 1 H, 3JH,H 12 Hz, 5JH,H 2

Hz, CH10) , 8.18 (d, 1 H, 5JH,H 2 Hz, CH8), 7.03 (dd, 1 H, 3JH,H 8 Hz, 5JH,H 2 Hz, CH3),

6.96 (dd, 1 H, 3JH,H 8 Hz, 5JH,H 2 Hz, CH1), 6.92 (s, 1 H, CH5), 6.53 (dd, 1 H, 3JH,H 8 Hz,3JH,H 7 Hz, CH2), 3.26 (sept, 1 H, 3JH,H 7 Hz, CHMe2), 3.22 (t, 2 H, 3JH,H 8 Hz, CH13),

2.33 (t, 2 H, 3JH,H 7 Hz, CH19), 1.85 (m, 2 H, CH14), 1.53 (d, 6 H, 3JH,H 7 Hz, CHMe2),

1.41 (m, 2 + 2 + 2 H, CH15 + CH20 + CH21), 0.94 (t, 3 H, 3JH,H 7 Hz, CH16), 0.84 (t, 3 H,3JH,H 7 Hz, CH22). 13C{1H} NMR (C6D6): δ 156.11 (s, C7), 143.38 (s, quaternary C),

141.56 (s, quaternary C), 138. 95 (s, C10), 131.95 (quaternary C), 129.90 (broad s,

CH11), 127.33 (s, CH3), 126.95 (s, CH2), 125.69 (s, C6), 124.46 (s, CH1), 124.03 (s, CH8),

115.47 (s, CH5), 99.44 (s, C17/18), 82.06 (s, C17/18), 36.53 (s, CHMe2), 34.22 (s, CH14),

33.86 (s, CH13), 30.63 (s, CH20), 25.27 (s, CHMe2), 23.76 (s, CH15), 22.81 (s, CH21),

20.41 (s, CH19), 14.63 (s, CH16), 14.10 (s, CH22). 11B{1H} NMR (C6D6): δ 28.29 (broad

s). UV-Vis (ε(104 L mol-1 cm-1)): λmax(CH2Cl2) = 453 (0.5), 322 (2.5), 289 (1.9) nm;

λmax(n-hexane) = 452 (0.3), 323 (3.4), 272 (2.2) nm. Fluorescence (cyclohexane): λmax =

486, 521 nm. Cyclic Voltammetry (vs. SCE): Ered(THF) = –2.10 V; Eox(THF) = +1.00

V. HR-MS for C25H32N11B (M+): 357.26278 (calculated), 357.26631 (found).

Synthesis of 5c-H. To a solution of 4c-H (52 mg, 0.16 mmol) in toluene (15 mL) was

added PtCl2 (2 mg, 8 µmol), and the mixture stirred at 100 oC for 20 hrs. After removing

volatiles in vacuo, the brown solid was extracted with hexane, and loaded onto a column

of neutral alumina. Subsequent elution with Et2O, followed by slow evaporation from

this solvent, gave 5c-H as orange crystals. Yield: 41 mg (79%).

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N

B

1H NMR (C6D6): δ 8.98 (d, 2H, 3JH,H 8 Hz, CH7), 8.31 (t, 1H, 3JH,H 8 Hz, CH8), 7.70 (d,

2H, 3JH,H 8 Hz, CH2), 7.63 (s, 2H, CH4), 7.57 (t, 1H, 3JH,H 8 Hz, CH1), 3.44 (t, 4H, 3JH,H 8

Hz, CH9), 1.97 (m, 4H, 3JH,H 8 Hz, CH10), 1.48 (tq, 4H, 3JH,H 8 Hz, CH11), 1.00 (t, 6H,3JH,H 8 Hz, CH12). 13C{1H} NMR (C6D6): δ 151.82 (s, C5), 139.48 (s, C3), 131.53 (broad

s, C6) 127.46 (s, CH1), 127.02 (s, CH7), 122.58 (s, C8), 119.14 (s, CH2), 116.73 (s, CH4),

33.94 (s, CH9), 33.69 (s, CH10), 23.85 (s, CH11), 14.67 (s, CH12). 11B{1H} NMR (C6D6):

δ 22.23 (broad s). UV-vis (ε(104 L mol-1 cm-1)): λmax(CH2Cl2) = 439 (0.12), 341 (1.8),

320 (8.4), 288 (2.0) nm, ; λmax(n-hexane) = 445 (0.15), 345 (1.7), 321 (8.5), 288 (2.2) nm.

Fluorescence (cyclohexane): λmax = 478, 511 nm; φf = 0.16, τf = 79 ns (χ2 = 0.41). HR-

MS for C22H26N11B (M+): 315.21583 (calculated), 315.21639 (found). Cyclic

Voltammetry (vs. SCE): E1/2(THF) = –2.02 V. TGA: Tonset = 175 oC, T5% = 210 oC.

M.P. = 89 oC (DSC).

Synthesis of 5c-iPr. To a solution of 4c-iPr (200 mg, 0.56 mmol) in toluene (50 mL)

was added PtCl2 (8 mg, 30 µmol), and the mixture stirred at 90 oC for two days. After

removing volatiles in vacuo, the brown solid was extracted with n-hexane, and loaded

onto a column of neutral alumina. Elution with Et2O, followed by slow evaporation of

this solution gave 5c-iPr as yellow plates which were suitable for X-ray diffraction.

Yield: 189 mg (95%).

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N

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1H NMR (C6D6): δ 8.98 (s, 2H, CH7), 7.76 (d, 2H, 3JH,H 8 Hz, CH2), 7.70 (s, 2H, CH4),

7.60 (t, 1H, 3JH,H 8 Hz, CH1), 3.72 (sept, 1H, 3JH,H 7 Hz, CHMe2), 3.52 (t, 4H, 3JH,H 8 Hz,

CH9), 2.04 (quin, 4H, 3JH,H 8 Hz, CH10), 1.74 (d, 6H, 3JH,H 7 Hz, CHMe2), 1.53 (tq, 4H,3JH,H 8 Hz, CH11), 1.00 (t, 6H, 3JH,H 8 Hz, CH12). 13C{1H} NMR (C6D6): δ 151.29 (s, C5),

142.71 (s, C8), 139.09 (s, C3), 131.91 (broad s, C6) 126.87 (s, CH1), 125.55 (s, CH7),

119.10 (s, CH2), 116.84 (s, CH4), 37.96 (s, CHMe2), 33.78 (s, CH9), 33.64 (s, CH10),

26.71 (s, CHMe2), 23.79 (s, CH11), 14.71 (s, CH12). 11B{1H} NMR (C6D6): δ 22.12

(broad s). UV-vis (ε(104 L mol-1 cm-1)): λmax(CH2Cl2) = 477 (0.02), 446 (0.10), 323

(8.9), 290 (1.8) nm, ; λmax(n-hexane) = 485 (0.1), 452 (0.1), 323 (9.0), 290 (1.8) nm.

Fluorescence (cyclohexane): λmax = 488, 521 nm; φf = 0.19, τf = 59 ns (χ2 = 0.82). HR-

MS for C25H32N11B (M+): 357.26278 (calculated), 357.25976 (found). Cyclic

Voltammetry (vs. SCE): E1/2(THF) = –1.82 V. TGA: Tonset = 76 oC, T5% = 204 oC. M.P.

= 84 oC (DSC).

S 12

Table S1. Calculated NICS(1), NICS(1)zz, NICS(0) and NICS(0)zz for 5a-H[3] and pyrene.a,b

N

B

i

ii

iii

iv

v

NICS(1) NICS(1)zz NICS(0) NICS(0)zz

5a-H i –13.75 –35.78 –12.94 –19.41

ii –9.48 –23.21 –7.59 –5.85

iii –15.12 –41.10 –13.84 –28.11

Pyrene iv –14.03 –35.58 –12.71c –19.63

v –7.89 –16.49 –5.08c +3.93[a] Values are reported in ppm. [b] B3LYP/6-31G* level. [c] These values arein good agreement with those published previously.[4]

S 13

Table S2. Experimental and Calculated Bond Lengths of 5b-iPr and 5a-H used for NICS Computations.

C7

C8N1

C4

C5C6

B1C1

C2

C3C9

C10C11

C12C13

C14

5b-iPrX-Ray (Å)

5b-iPrB3LYP/6-31G* (Å)

5a-H modelB3LYP/6-31G* (Å)

5a-Ha

X-Ray (Å)N1-B1 1.457(4) 1.454 1.456 1.456(4)B1-C1 1.501(4) 1.515 1.511 1.502(4)C1-C2 1.438(3) 1.438 1.421 1.415(4)C2-C3 1.372(4) 1.384 1.377 1.359(4)C3-C4 1.426(4) 1.424 1.428 1.426(3)N1-C4 1.400(3) 1.398 1.401 1.398(3)N1-C8 1.394(3) 1.398 1.401 1.407(3)C4-C5 1.382(4) 1.400 1.399 1.391(3)C5-C6 1.373(4) 1.392 1.391 1.373(4)C6-C7 1.372(4) 1.391 1.391 1.375(4)C7-C8 1.385(4) 1.401 1.399 1.378(4)C8-C9 1.425(4) 1.423 1.428 1.423(4)C9-C10 1.373(4) 1.385 1.377 1.357(4)

C10-C11 1.440(4) 1.436 1.421 1.423(4)B1-C11 1.506(4) 1.514 1.511 1.492(4)

C11-C12 1.412(3) 1.406 1.405 1.402(4)C12-C13 1.392(3) 1.407 1.404 1.393(4)C13-C14 1.407(3) 1.409 1.404 1.394(4)C1-C14 1.403(3) 1.404 1.405 1.401(4)

[a] Not used in NICS computations.

S 14

Figure S1. Cyclic voltammogram of 1 mM THF solution of 5a-H (0.1 M[nBu4N][PF6] supporting electrolyte; scan rate of 200 mV/s).

Figure S2. EPR spectrum of [5a-H]·-[Li]+ in THFat 243 K.

Fc/Fc+

E1/2 = +0.54 V

5a-H/[5a-H]·–

E1/2 = –1.98 V

giso = 2.003

S 15

Figure S3. (a) Spin density map and (b) SOMO of 5a-H.

S 16

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

450 470 490 510 530 550 570 590

λ /nm

arb

itra

ry u

nit

s4.92E-3 M2.85E-3 M1.14E-3 M5.02E-4 M2.91E-4 M9.31E-5 M5.21E-5 M1.46E-5 M6.25E-6 M2.13E-6 M

Figure S4. Emission spectra (330 nm excitation) of cyclohexane solutions of 5a-H atvarious concentrations. Spectra normalized at 510 nm.

300 350 400 450 500

λ/n

Figure S5. Single crystal excitation spectrum (λem = 520 nm) of 5c-iPr.Excitation and emission bandwidths were set to 2.5 and 10 nm, respectively.

S 17

[1] D. J. H. Emslie, W. E. Piers, M. Parvez, Angew. Chem. Int. Ed. 2003, 42, 1252.[2] K. A. Bunten, A. K. Kakkar, Macromolecules 1996, 29, 2885-2893.[3] Metrical parameters used for the optimized geometry are those of 5b-iPr with the

phenyl and isopropyl substituents removed.[4] R. W. A. Havenith, J. H. van Lenthe, F. Dijkstra, L. W. Jenneskens, J. Phys.

Chem. A 2001, 105, 3838-3845.