Synthesis, Structure, And Reactivity Of Complexes Of Early D-Block Metals Featuring Multiple-Bonds To P-Block Elements And Study Of Phosphonium Ylides As A Carbene Source For Alkylenation Of Iridium-Carbon Bonds

Molecules displaying multiple-bonding between a variety of p-block elements and first-row d-block metals are disclosed. Sc, Ti, and V complexes supported by (PNP)– (N[2-PiPr2-4-methylphenyl]) and/or (BDIDipp)– (N,N′-bis(2,6-diisopropylphenyl)-3,5-dimethyl-β-diketiminate) ligands were successfully synthesised and the reactivity and physical properties thereof were studied. Scandium alkylidenes and phosphonioalkylidynes could be stabilized by association with trialkylaluminium species. Bistelluridotitanates, the first examples of complexes featuring two group 16 element atoms terminally bound to a single group 4 metal centre could be obtained in a simple, one-pot procedure from the corresponding bisalkyl complexes, elemental tellurium and a reductant via Ti–C insertion of Te and elimination of telluroethers. Two distinct types of Te–Te bonds could be forged by either isocyanide coordination to, or chemical reduction of [(PNP)V(Te)2]. The novel bisselenide [(PNP)V(Se)2] could also be obtained. The above-mentioned species and others were analysed spectroscopically, magnetometrically, voltametrically, by single-crystal X-ray diffractometry, and by computational methods. A study of the ability of the ylide H2CPPh3, often called the Wittig reagent, to deliver its methylene group to Ir(III) species [Cp*(Me3P)Ir(CH3)(OTf)], a complex documented to activate C–H bonds of hydrocarbons under mild conditions, revealed a migration reaction that resulted in the formation of new C–C bond. This reaction and the resulting products were examined with a combination of NMR spectroscopy, single-crystal diffractometry, and quantum chemical calculations which suggested the intermediacy of a mid-valent iridium carbene species.