Bimetallic, Spirocyclic, Methylene-Bridged Carbene Complexes of Rhodium and Palladium Derived by Stepwise Metalations of Lithiated Bis(diphenylphosphoranotrimethylsilylimido)methandiide

Twinned versus linked organometallics - bimetallic "half-baguette" pentalenide complexes of Rh(I)

The application of Mg[Ph4Pn] and Li·K[Ph4Pn] in transmetalation reactions to a range of Rh(I) precursors led to the formation of "half-baguette" anti-[RhI(L)n]2[μ:η5:η5Ph4Pn] (L = 1,5-cyclooctadiene, norbornadiene, ethylene; n = 1, 2) and syn-[RhI(CO)2]2[μ:η5:η5Ph4Pn] complexes as well as the related iridium complex anti-[IrI(COD)]2[μ:η5:η5Ph4Pn]. With CO exclusive syn metalation was obtained even when using mono-nuclear Rh(I) precursors, indicating an electronic preference for syn metalation. DFT analysis showed this to be the result of π overlap between the adjacent M(CO)2 units which overcompensates for dz2 repulsion of the metals, an effect which can be overridden by steric clash of the auxiliary ligands to yield anti-configuration as seen in the larger olefin complexes. syn-[RhI(CO)2]2[μ:η5:η5Ph4Pn] is a rare example of a twinned organometallic where the two metals are held flexibly in close proximity, but the two d8 Rh(I) centres did not show signs of M-M bonding interactions or exhibit Lewis basic behaviour as in some related mono-nuclear Cp complexes due to the acceptor properties of the ligands. The ligand substitution chemistry of syn-[RhI(CO)2]2[μ:η5:η5Ph4Pn] was investigated with a series of electronically and sterically diverse donor ligands (P(OPh)3, P(OMe)3, PPh3, PMe3, dppe) yielding new mono- and bis-substituted complexes, with E-syn-[RhI(CO)(P{OR})3]2[μ:η5:η5Ph4Pn] (R = Me, Ph) characterised by XRD.

Geminal Dianions Stabilized by Main Group Elements

This review is dedicated to the chemistry of stable and isolable species that bear two lone pairs at the same C center, i.e., geminal dianions, stabilized by main group elements. Three cases can thus be considered: the geminal-dilithio derivative, for which the two substituents at C are neutral, the yldiide derivatives, for which one substituent is neutral while the other is charged, and finally the geminal bisylides, for which the two substituents are positively charged. In this review, the syntheses and electronic structures of the geminal dianions are presented, followed by the studies dedicated to their reactivity toward organic substrates and finally to their coordination chemistry and applications.

Heterobimetallic Pd-K carbene complexes via one-electron reductions of palladium radical carbenes

Heterobimetallic Pd-K carbenes featuring Pd-C_carbene-K moieties were synthesized via an unprecedented sequential substitution/reduction reaction from a radical precursor, [{PC˙(sp²)P} ^tBuPdI] ([PC(sp²)P] ^tBu = bis[2-(di-iso-propylphosphino)-4-tert-butylphenyl]methylene). Polymeric structures were observed in the solid state for the heterobimetallic compounds that can be interrupted in the presence of a donor solvent.

Syntheses, structures and flexible coordination of sterically demanding di- and “tri”-lithiated methandiides

Sequential lithiation of a sterically demanding bis(iminophosphoranyl)methane afforded di- and trianionic methandiide lithium complexes and their structures and coordination behaviour have been studied with solid state and solution methods.

A geminal dithallated bis(iminodiphenylphosphorano)methine carbon bridged dimer bound by Tl-Tl interactions

A geminal dithallated bis(iminodiphenylphosphorano)methine carbon complex was prepared and isolated as a solid dimer, stable in an inert atmosphere. It has been fully characterized in both solution and solid states. Bonding has been assessed with the aid of DFT calculations. All data demonstrate that the dimer contains a single carbon center sigma bound to two Tl((I)) atoms (Tl((I))-C-Tl((I))). Two geminal monomers associate via Tl((I))-Tl((I)) interactions to form the dimer.