Binuclear Iron and Ruthenium Complexes with Bis(diazene) or Bis(diazenido) Bridging Ligands: Synthesis, Characterization, X-ray Crystal Structure, and Electrochemical Studies

Abstract

Binuclear complexes [(MHP4)2(μ-HNNAr−ArNNH)](BPh4)2 [M = Fe, Ru; P = P(OMe)3, P(OEt)3, PPh(OEt)2; Ar−Ar = 4,4‘-C6H4−C6H4, 4,4‘-(2-CH3)C6H3−C6H3(2-CH3), 4,4‘-C6H4−CH2−C6H4] were prepared by allowing hydride species MH2P4 to react with bis(diazonium) salts (N2Ar−ArN2)(BF4)2 in a 2:1 ratio at low temperature. The compounds were characterized by 1H and 31P{1H} NMR spectroscopy (including 15N isotopic substitution) and an X-ray crystal structure determination. The complex [{FeH(P(OEt)3)4}2{μ-4,4‘-HNN(2-CH3)C6H3−C6H3(2-CH3)NNH}](BPh4)2 crystallizes in the space group P1 with a = 16.105(5), b = 17.551(6), c = 11.539(3) A; α = 96.41(2), β = 84.49(2), γ = 97.97(2)°; and Z = 2. The structure is centrosymmetric and consists of binuclear cations with the two iron atoms in an octahedral environment having the hydride and the diazene ligands in mutually cis positions. The [(MHP4)2(μ-HNNAr−ArNNH)]2+ cations reacted with mono(diazonium) (RN2)BF4 salts to give the binuclear bis(diazene) derivatives [{M(RNNH)P4}2(μ-HNNAr−...