Unconventional approach for the synthesis of nickel and platinum complexes of 1,3,6-azadiphosphacycloheptanes

The approach to the synthesis of bis-phospninesulfides and nickel and platinum chelate complexes of 1,3,6-azadiphosphacycloheptanes is supposed. The approach is based on the ability of 14-membered 1,8-diaza-3,6,10,13-tetraphosphacyclotetradecanes undergo the reversible transformation to the mixture of meso- and rac-isomers of 7-membered bisphosphines during the solution. The reaction of 1,8-diaza-3,6,10,13-tetra-phosphacyclotetradecanes with elementary sulfur results in 14-membered tetra(phosphinesulfides) or 7‑membered bis(phosphinesulfides) that depends on the reaction conditions. The reaction of 1,3,6-azadiphosphacycloheptanes, forming by the reversible dissociation of 14-membered tetraphosphines in chloroform, with Ni(CH3CN)6(BF4)2 and Pt(COD)Cl2 give corresponding chelate complexes. The structures of meso-isomer of 1-cyclohexyl-3,6-diphenyl-1-aza-3,6-diphosphacycloheptan-3,6-disulfide 8, bis-(κ2-1-isopropyl-3,6-diphenyl-1-aza-3,6-diphosphacycloheptane)nickel bis(tetrafluoroborate) 9, bis-(κ2-1-icyclohexyl-3,6-diphenyl-1-aza-3,6-diphosphacycloheptane)chloronickel tetrafluoroborate 10 and cis-dichloro-(κ2-1-cyclohexyl-3,6-diphenyl-1-aza-3,6-diphosphacycloheptane)-platinum(II) 13 were established by single crystal XRD analysis.