A C2-symmetric analogue of dppf: synthesis and structures of the indenyl-diphosphine complex 1,3-(Ph2PSe)2(C9H6) and the racemic and meso isomers of the heterobimetallic complex Mo(CO)4(1-PPh2-η-C9H6)2Fe

The preparation, isolation and characterisation of 1,3-bis(diphenylphosphino)indene (1) from indene and chlorodiphenylphosphine is described. The reaction of 1 with selenium gives the diselenide adduct 1,3-bis(diphenylselenophosphino)indene (2) which was characterised crystallographically. Deprotonation of 1 and treatment with ferrous chloride gives the unstable tetraphosphine complex bis(1,3-bis(diphenylphosphino)indenyl)iron(II) (3). Complex 3 decomposes to the diphosphine complex bis(1-diphenylphosphinoindenyl)iron(II) (4) via replacement of one diphenylphosphine substituent per indenyl ligand by a hydrogen atom. Complex 4 was also prepared by treatment of two equivalents of 1-diphenylphosphinoindenide with ferrous chloride. The heterobimetallic complex tetracarbonyl(bis(1-diphenylphosphinoindenyl)iron(II))molybdenum(0) (5) was also prepared and crystal structures of both the meso (5a) and C₂-symmetric racemic (5b) isomers are reported.