Kattesh V. Katti

Heterobifunctional Phosphorus-Nitrogen Compounds: Iminophosphoranophosphines and Their Complexes

Abstract Heterobifunctional phosphorus compounds have been prepared by oxidizing one phosphorus atom of a bis(phosphine) with azides. A variety of backbone structures have been used with one and two carbon chains, saturated and unsaturated structures and RN. Some degree of steric control appears to limit the extent of oxidation in cis bis(phosphines) with rigid backbones. Trimethylsilyl azide gives silylated iminophosphoranes with a reactive functionality on the imine nitrogen which can be replaced via metathetical elimination of Me3SiX or converted to the trimethylsiloxy metal derivative by rearrangement of the trimethylsilyl group to terminal oxygen of a highly oxidized metal oxo precursor. Structural features of several examples of the heterobifunctional phosphorus compounds and their derivatives are described.

New Inorganic and Organometallic Heterocyclic Compounds Derived From Novel Heterodifunctional Phosphorus-Nitrogen Ligands

Abstract The first examples of phosphiniminatophosphanes, Me3SiN=P(Ph2)(CH2)nP(Ph2), were prepared from the reactions of the diphosphanes, Ph2P(CH2)nPPh2 [n = 1 and 2], with N3SiMe3. ARPHOS, Ph2As(CH2)2PPh2, is oxidized only at phosphorus to yield a new phosphiniminatoarsane. These new heterodifunctional ligands with both hard and soft centres react with metal compounds to yield chelates and metal-nitrogen bonded metallacycles. The Rh(l) carbonyl derivatives of these ligands convert methanol to acetic acid in the presence of CO and CH3l. Re(VII) reacts with Ph2PCH2(Ph2)P=NSiMe3 to form a Re-N metallacycle. Alkyl and aryl germanium halides suffered germanotropic rearrangements and loss of organic subsituents in reaction with the doubly oxidized diphosphane, Me3SiN=P(Ph2)CH2(Ph2)P=NSiMe3, to form a new germanium spirocycle containing both Ge-C and Ge-N bonds. The isomeric spirocycle with only Ge-N bonds was also prepared from GeCl4 and the bis(phosphiniminato)methane and from a germanium diazide and dppm. S...

Methylene Bridged P(III) and P (V) Phosphiniminato-Phosphanes: Versatile Ligands And Substituents for Metals and Metalloids

Abstract Recent studies1 have shown that the mono oxidized phosphanolminatophosphane Me3SiN=PPh2CH2PPh2 1 is a versatile ligand for a variety of transition metals in high and low oxidation states. This heterodifunctional ligand may bind to metals via the “hard” (N) or the “soft”(P(III)) centres; the former favours high oxidation states and “early” transition metals, the latter, low oxidation states and “late” transition metals. Monodentate or bidentate complexation is observed and in the latter case chelation or bridging is possible. Elimination of Me3SiCl from a metal halide or migration of Me3Si group to a terminal oxygen atom leads to metal nitrogen sigma bond formation. To modify the basicity at nitrogen a variety of approaches have been employed. Metathetical elimination of Me3SiX from activated halogenated aromatics leads to functionalisation at N. The R3Sn and R3Ge analogs of 1 have also been made by extensions of the Staudinger reaction. Reactions of 1 and its N-aromatic, N-Ge, and N-Sn analogs wi...

Cyclometallaphosphiniminatopxosphane (and Arsane) Complexes of “Early” and “Late” Transition Metals Derived from Novel Heterodifunctional Phosphorus and Arsenic Ligands

Abstract A new heterodifunctional ligand system Me3EN=PPh2(CH2)nQPh2 (E - Si, Ge; Q = P, As; n − 1, 2) has been developed. These heterodifunctional ligands provide hard (N) and soft (P, As) base character appropriate for combination with “early” and “late” transition metals respectively to form chelate and monodentate complexes. In addition M-N [sgrave] bond formation by means of metathetical Me3EX elimination leads to a variety of useful functionalized phosphanes. Interactions with Ti(IV), Mo(O), W(O), Pd(II), Rh(I) and Ir(I) indicate the versatility of these ligands