The reaction of tin dichloride with catalytically-relevant group 10 metal precursors [M(Cl)(X)(2-PyPPh(2))(2)] (M = Ni, Pd, Pt; 2-PyPPh(2) = 2-pyridyldiphenylphosphine; X = Cl, Me) provides easy access to unprecedented cationic dichlorostannylene complexes [M(X)(2-PyPPh(2))(2)(SnCl(2))](+) where the M-Sn bond is bridged by two head-to-head coordinated 2-PyPPh(2) ligands. The formation of such species instead of the classical neutral trichlorostannyl derivatives [M(X)(SnCl(3))(2-PyPPh(2))(2)] offers a new insight on the specific effect of the SnCl(2) cocatalyst in group 10 metal catalyzed transformations.

Reaction of [PdClMe(P^N)2] with SnCl2 followed by Cl-abstraction leads to apparent Pd-C bond activation, resulting in methylstannylene species trans-[PdCl{(P^N)2SnClMe}][BF4] (P^N = diaryl phosphino-N-heterocycle). In contrast, reaction of Pt analogues with SnCl2 leads to Pt-Cl bond activation, resulting in methylplatinum species trans-[PtMe{(P^N)2SnCl2}][BF4]. Over time, they isomerise to methylstannylene species, indicating that both kinetic and thermodynamic products can be isolated for Pt, whereas for Pd only methylstannylene complexes are isolated. Oxidative addition of RSnCl3 (R = Me, Bu, Ph) to M(0) precursors (M = Pd or Pt) in the presence of P^N ligands results in diphosphinostannylene pincer complexes trans-[MCl{(P^N)2SnCl(R)}][SnCl4R], which are structurally similar to the products from SnCl2 insertion. This showed that addition of RSnCl3 to M(0) results in formal Sn-Cl bond oxidative addition. A probable pathway of activation of the tin reagents and formation of different products is proposed and the relevancy of the findings for Pd and Pt catalysed processes that use SnCl2 as a co-catalyst is discussed.

Low-temperature reaction of [Li(PC4H2 t-Bu2)·2thf] (thf = tetrahydrofuran) (7) with [Co(acac)2] (Hacac = acetylacetone) gives the reactive half-sandwich complex [Co(η5-PC4H2 t-Bu2)(acac)] (6). The crystal structure of 6 shows an unusual ene/2-phosphaallyl distortion, which indicates an a‘ symmetric SOMO of the type found in the related alicyclic complex [M(η5-Cp*)(acac)] (5). Reaction of 6 with the bulky lithium cyclopentadienide Li(1,3-C5 t-Bu2H3) (12) results in the displacement of acetylacetonate and formation of the corresponding air-sensitive purple monophosphacobaltocene [Co(η5-2,5-PC4 t-Bu2H2)(η5-1,3-C5 t-Bu2H3)] (10), which shows fluxional behavior in solution.