Synthesis, Structure and Nickel Carbonyl Complexes of Dialkylterphenyl Phosphines.

The experimental and computational characterization of a series of dialkylterphenyl phosphines, PR2 Ar' is described. The new P-donors comprise five compounds of general formula PR2 Ar Dtbp 2 (R=Me, Et, iPr, c-C5 H9 and c-C6 H11 ); Ar Dtbp 2 = 2,6-C6 H3 -(3,5-C6 H3 -(CMe3 )2 )2 ), and another five PR2 Ar' phosphines containing the bulky alkyl groups iPr, c-C5 H9 or c-C6 H11 , in combination with Ar'=Ar Xyl 2 , Ar Xyl ' 2 , or Ar Ph 2 (L1-L10). Steric and electronic parameters have been determined computationally and from IR and X-ray data obtained for the phosphines and for some derivatives, including tricarbonyl and dicarbonyl nickel complexes, Ni(CO)3 (PR2 Ar') and Ni(CO)2 (PR2 Ar'). In the solid state, the free phosphines PR2 Ar' adopt one of the three possible structures formally related by rotation around the Cipso -P bond. Details on their relative energies and on the influence of the free phosphine structure on its coordination chemistry towards Ni(CO)n (n = 2, 3) fragments has been obtained by experimental and computational methods.

A dicoordinate gold(I)-ethylene complex.

The use of the exceptionally bulky tris-2-(4,4'-di-tert-butylbiphenylyl)phosphine ligand allows the isolation and complete characterization of the first dicoordinate gold(I)-ethylene adduct, filling a missing fundamental piece on the organometallic chemistry of gold. Besides, the bonding situation of this species has been investigated by means of state-of-the-art Density Functional Theory (DFT) calculations indicating that π-backdonation plays a minor role compared with tricoordinate analogues.

Reactivity of a gold(i)/platinum(0) frustrated Lewis pair with germanium and tin dihalides.

The reactivity of germanium and tin dichlorides with a transition metal-only frustrated Lewis pair based on Au(i) and Pt(0) compounds bearing bulky phosphine ligands is described in this work. We have examined both the reactivity of tetrylene dihalides towards the individual components of the metallic pair, as well as under metal/metal cooperative conditions. These studies allowed us to isolate several uncommon homo- and heterometallic structures. Computational methods have been employed to investigate the bonding scheme of one of these highly-reduced metallic aggregates. In addition, we have developed a tin-promoted strategy to access heteroleptic diphosphine platinum(0) compounds.