Comparative chemistry of bipyrazyl and bipyridyl metal complexes: Spectroscopy, electrochemistry, and photoanation

Article abstract of DOI:10.1021/ic00136a030

The photoanation of the bipyrazyl complex Ru(bpz)₃(PF₆)₂, in acetonitrile containing chloride ion, leads to the formation of cis-Ru(bpz)₂(CH₃CN)Cl⁺ (maximum quantum yield 0.37), cis-Ru(bpz)₂Cl₂ (maximum quantum yield 0.001), and an unidentified mono(bipyrazyl)ruthenium(II) derivative. The mechanism of this reaction is discussed. Reaction of M(CO)₆ (M = W, Mo) with bipyrazyl yields M(CO)₄bpz. The electronic, vibrational, and ¹H NMR spectra and electrochemistry of these products were compared with those of their bipyridyl analogues. It is concluded that bipyrazyl is no better a π acceptor than bipyridyl because of weaker σ bonding leaving the metal ion more positvely charged.