CHEM 522 Chapter 01 Introduction. Transition Metal Organometallic Chemistry Organic versus inorganic chemistry Transition metals –Oxidation state –d orbitals

Download CHEM 522 Chapter 01 Introduction. Transition Metal Organometallic Chemistry Organic versus inorganic chemistry Transition metals –Oxidation state –d orbitals

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<ul><li><p>CHEM 522Chapter 01Introduction</p></li><li><p>Transition Metal Organometallic Chemistry Organic versus inorganic chemistryTransition metalsOxidation stated orbitalsLigands (L)Coordination compounds or complexes (MLn)</p></li><li><p>Werner ComplexesLewis acids and basesCommon typesOctahedral ML6Tetrahedral ML4Square planar ML4Trigonal bipyramid ML5Square pyramid ML5Stereochemistrycis, trans isomersoptical isomers </p></li><li><p>BridgingWhen the ligand have more than one site for binding it could make a bridge</p><p>3c-2e bond</p></li><li><p>Chelate EffectChelating ligand can bind through more than one donor atomExample ethylene diamineChelating ligands are favored from entropy point of view</p><p>M(NH3)6n+ + 3en M(en)3n+ + 6NH3 </p></li><li><p>The Trans EffectTrans influence: certain ligands make ligands trans to it more labile.For platinum complexes the order is:OH- &lt; NH3 &lt; Cl- &lt; CN- , CO &lt; PR3 &lt; H-</p></li><li><p>Hard and Soft BasesHard base small and high chargeSoft base large and low charge</p><p>Soft-soft and hard-hard interaction is prefer over hard-soft interaction</p></li><li><p>Effect of ligands on d-orbitals</p></li><li><p>Octahedral Complex and d-Orbital Energies</p></li><li><p>Crystal Field Theory</p></li><li><p>Energy Effects in Octahedral Complexes</p></li><li><p>Crystal Field Theory</p></li><li><p>o versus P Hunds rulepairing energy considerations</p><p> &gt; Plow spin &lt; Phigh spin</p></li><li><p>Magnetic Properties of CoordinationCompounds and Crystal Field Theory.</p></li><li><p>Magnetic momentMagnetic moment ss = n(n+2)Where n = number of unpaired electronsn s11.7322.8333.8744.9055.92 </p></li><li><p>Colors of Transition-Metal ComplexesTransition-metal complexes can be red, purple, blue, green, yellow, orange, etc.Most other compounds are colorless (or, white).Why are transition-metal complexes special?</p></li><li><p>Absorption of Light</p><p>If a compound is colored, it must absorb visible light.To absorb visible light a compound must have an empty (or partially filled) electronic energy level that is just a little higher in energy than another filled (or partially filled) level.The d orbitals in transition-metal ions often meet this test.</p></li><li><p>t2g1eg0 &gt; t2g0eg1 </p></li><li><p>Spectrochemical Series</p><p>Ligands can be arranged into a spectrochemical series according to the magnitude of splitting of the d-orbitalsLarge splitting is associated with strong field ligandsSmall splitting is associated with weak field ligandsCN-1&gt;en&gt;NH3&gt;H2O&gt;F-&gt;SCN-&gt; Cl-&gt; Br-&gt; I-</p></li><li><p>Crystal field splitting</p></li><li><p>Weak and Strong Field Ligands</p></li><li><p>Tetrahedral Crystal Field</p></li><li><p>Tetrahedral Splitting Pattern of d-Orbitals</p><p>O&gt;T thus no strong field vs. weak field cases</p></li><li><p>Square Planar Crystal Field</p></li><li><p>Pi Bond Donor</p></li><li><p>Pi Bond Acceptor</p></li><li><p>Interaction with -donor ligands</p></li><li><p>Interaction with -acceptor ligands</p></li><li><p>-donor ligands -acceptor ligands</p></li><li><p> MO diagram of M(CO)6 </p></li><li><p>Types of LigandsSimple sigma ()donorM-ClM-NH3M can also bond to C=C bond and H-H bond This is known as hapticity ()2 H2CCH2 2 H2</p></li><li><p>M-H2 Bond (2)</p></li><li><p>Interaction with Double Bond (2)</p></li><li><p>Interaction with Double Bond</p></li><li><p>(5) (1)</p></li><li><p>Type of Ligands bonding electron pair donors (always consider 2-e are donated by ligand so ligand will be NH3, H-, R3C-, bonding, strong -acceptor CO, CN-, PR3, bonding -donor Cl-, F-, -bonding electron pair donor -acceptor C2H4, O2, </p></li><li><p>Common LigandsTable 1.10CO, CN-CpPR3bipydpeacac</p></li></ul>

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