From a Diphosphanegermylene to Nickel, Palladium, and Platinum Complexes Containing Germyl PGeP Pincer Ligands

The PGeP pincer-type germylene Ge(N-CH2PtBu2)C6H4 (1) has been used to prepare a family of group10 metal complexes, namely, [MCl{kappa P-3,Ge,P-GeCl(NCH2PtBu2)(2)C6H4}] (M=Ni (2(Ni)), Pd (2(Pd)), Pt (2(Pt))), featuring a chloridogermyl PGeP pincer ligand and a Cl-Ge-M-Cl bond sequence. Their reactivity is not initially centered on the metal atom but on their Ge atom. Complexes 2(Ni) and 2(Pd) easily led to the hydrolyzed products [Ni2Cl2{mu-(kappa P-3,Ge,P-Ge(NCH2PtBu2)(2)C6H4)(2)O}], which features a Cl-Ni-Ge-O-Ge-Ni-Cl bond sequence, and [PdCl{kappa P-3,Ge,P-Ge(OH)(NCH2PtBu2)(2)C6H4}], which contains a hydroxidogermyl PGeP pincer ligand (2(Pt) is reluctant to undergo hydrolysis). Simple chloride exchange reactions led to the methoxidogermyl, methylgermyl, and phenylgermyl derivatives [MCl{kappa P-3,Ge,P-GeR(NCH2PtBu2)(2)C6H4}] (M=Pd, Pt; R=OMe, Me, Ph). Whereas the palladium complexes [PdCl{kappa P-3,Ge,P-GeR(NCH2PtBu2)(2)C6H4}] (R=Me, Ph) reacted with more MeLi or PhLi to give palladium black and GeR2(NCH2PtBu2)(2)C6H4 (R=Me, Ph), similar reactions with the analogous platinum complexes afforded the transmetalation derivatives [PtR{kappa P-3,Ge,P-GeR(NCH2PtBu2)(2)C6H4}] (R=Me, Ph). The short length of the CH2PtBu2 arms of the PGeP pincer ligands forces the metal atoms of all these complexes to be in a very distorted square-planar ligand environment. The reactivity results have been rationalized with theoretical calculations.