Stannylenes based on pyrrole-phosphane and dipyrromethane-diphosphane scaffolds: syntheses and behavior as precursors to PSnP pincer palladium(II), palladium(0) and gold(I) complexes

2-Ditertbutylphosphanylmethylpyrrole (H(2)pyrmP(t)Bu(2)) and 2,2'-bis(diisopropylphosphanylmethyl)-5,5'-dimethyldipyrromethane ((HpyrmP(i)Pr(2))(2)CMe2) have been used to synthesize new P-donor-stabilized stannylenes in which the Sn atom is attached to one, SnCl(HpyrmP(t)Bu(2)) (1) and Sn{N(SiMe3)(2)}(HpyrmP(t)Bu(2)) (2), or two pyrrolyl-phosphane scaffolds, Sn(HpyrmP(t)Bu(2))(2) (3), or to a dipyrromethane-diphosphane scaffold, Sn(pyrmP(i)Pr(2))(2)CMe2 (4). It has been found that stannylenes 3 and 4 are excellent precursors to transition metal complexes containing PSnP pincer-type ligands. Their reactions with chlorido transition metal complexes have afforded [PdCl{kappa P-3,Sn,P-SnCl(HpyrmP(t)Bu(2))(2)}] (6), [PdCl{kappa P-3,Sn,P-SnCl(pyrmP(i)Pr(2))(2)CMe2}] (7) and [Au{kappa P-3,Sn,P-SnCl(HpyrmP(t)Bu(2))(2)}] (8), which contain a PSnP pincer-type chloridostannyl ligand. While complexes 6 and 7 are square-planar palladium(II) complexes, compound 8 is an uncommon gold(I) complex having a T-shaped coordination geometry with a very long Sn-Au bond (3.120 angstrom). The T-shaped palladium(0) complex [Pd{kappa P-3,Sn,P-Sn(pyrmP(i)Pr(2))(2)CMe2}] (9), which contains an unprecedented PSnP pincer-type stannylene that behaves as a Z-type (sigma-acceptor) ligand, has been prepared from 4 and [Pd(eta(3)-C3H5)(eta(5)-C5H5)].

Automated summary

The compounds H(2)pyrmP(t)Bu(2) and (HpyrmP(i)Pr(2))(2)CMe2 were used to synthesize new P-donor-stabilized stannylenes, demonstrating their potential as precursors to transition metal complexes.