Synthesis and Structure of Vanadium Halide Complexes Containing Diphosphine Ligands with Pendant Amines

A series of vanadium(III) diiodide complexes of the formula CpV(P R N R′ P R )I 2 [Cp = η 5 ‐C 5 H 5 ; P R N R′ P R = (R 2 PCH 2 ) 2 N(R′); R = Et, R′ = Me ( 1a ); R = Et, R′ = Ph ( 1b ); R = Ph, R′ = Me ( 1c )] is reported. The corresponding vanadium(II) monoiodide complexes of the formula CpV(P R N R′ P R )I [R = Et, R′ = Me ( 2a ); R = Et, R′ = Ph ( 2b ); R = Ph, R′ = Me ( 2c )] were prepared in THF by reduction of 1a – c with Zn powder. We report the preparation of the vanadium(II) complexes CpV(P Ph 2 N Ph 2 )I ( 3 ) (P Ph 2 N Ph 2 = 1,3,5,7‐tetraphenyl‐1,5‐diaza‐3,7‐diphosphacyclooctane) as well as trans ‐[VCl 2 (P Et N Me P Et ) 2 ] ( 4a ) and trans ‐[VCl 2 (P Et N Ph P Et ) 2 ] ( 4b ). These paramagnetic complexes are characterized by elemental analysis, 1 H NMR spectroscopy, and cyclic voltammetry for 2a , 2b , 3 and 4b . Complexes 1c , 2a – c , 3 , and 4b were also characterized by single‐crystal X‐ray crystallography. These complexes represent initial examples for the coordination chemistry of vanadium with P R N R′ P R and P Ph 2 N Ph 2 diphosphine ligands, which contain a pendant amino groups in the second coordination sphere.