Inorganic Heterocyclic Bis(phosphines): Syntheses and Structures of a 1,2-Bis(diazasilaphosphetidino)ethane and Its Nickel, Molybdenum, and Rhodium Complexes

Synthesis and characterization of a new, highly electron-rich, chelating bis(phosphine), based on the ethanediyl-linked inorganic heterocycle [Me2Si(μ-NtBu)2P], are reported. Treatment of nickel chloride with this bis(phosphine)
afforded square-planar cis-{[Me2Si(μ-NtBu)2PCH2]2NiCl2}, which features isometric nickel−chloride (2.2220(8) Å)
and nickel−phosphorus (2.1572(8) Å) bonds. The ligand reacted with cis-[(piperidine)2Mo(CO)4] to form colorless
cis-{[Me2Si(μ-NtBu)2PCH2]2Mo(CO)4}, which has distorted octahedral geometry and long Mo−P bonds (2.5461(18)
Å). Because of its potential applications in hydrogenation catalysis cis-{[Me2Si(μ-NtBu)2PCH2]2Rh(COD)}BF4 was
synthesized. This square-planar, cationic rhodium(I) complex, having symmetrical Rh−P (2.250(2) Å) and Rh−C
(2.305(6) Å) bonds, is structurally related to bis(phospholano)- and bis(phosphetano)rhodium species.