Diazoalkane complexes of ruthenium with tris(pyrazolyl)borate and bis(pyrazolyl)acetate ligands

Diazoalkane complexes [Ru(Tp)(N(2)CAr1Ar2)(PPh3)L]BPh4 (1 and 2) [Tp = tris(pyrazolyl) borate; L = P(OMe)(3), P(OEt)(3); Ar1 = Ar2 = Ph; Ar1 = Ph, Ar2 = p-tolyl; Ar1Ar2 = C12H8] were prepared by allowing chloro-compounds RuCl(Tp)(PPh3) L to react with diazoalkane in the presence of NaBPh4. Acrylonitrile CH2=C(H) CN reacts with diazoalkane complexes to give 3H-pyrazole derivatives [Ru(Tp){N=NC(Ar1Ar2)CH(CN)CH2}(PPh3){P(OMe)(3)}]BPh4 and [Ru(Tp){N=NC(Ar1Ar2)CH2C(H)CN}(PPh3)-{P(OMe)(3)}]BPh4 (3). Diazoalkane complexes [Ru(bpza)(N(2)CAr1Ar2)(PPh3)(2)]BPh4 (4) [bpza = bis(pyrazolyl)-acetate] were also prepared. All complexes were characterised by IR and NMR spectroscopy and X-ray crystal structure determination of [Ru(Tp){N2C(Ph)(p-tolyl)}(PP(h)3){P(OMe)(3)}]BPh4 (1b). The differences exhibited by [Ru(Tp){N2C(Ph)(p-tolyl)}(PPh3){P(OMe)(3)}](+) and [Ru(Cp){N2C(Ph)(p-tolyl)}(PPh3){P(OMe)(3)}](+), as regards coordination of the diazoalkane ligand and reactivity towards alkenes, were explained on the basis of a comparative DFT study.