Preparation of Azine Complexes of Ruthenium(II)

Aldazine complexes [RuCl(eta(6)-p-cymene){kappa(1)-[N=C(H)R1]-N=C(H)R1}L]BPh4 (1-4) [L=P(OMe)(3), P(OEt)(3), PPh(OEt)(2), PiPr(3); R1 = Ph, 4-CH3C6H4, 4-CH3OC6H4, Et] were prepared by allowing chloro compounds RuCl2(eta(6)-p-cymene)L to react with the azine R-1(H)C=N-N=C(H)R1 in ethanol. Depending on the nature of the phosphine ligand, the reaction of ketazine (CH3)(2)C=N-N=C(CH3)(2) with chloro compounds RuCl2(eta(6)-p-cymene)L yielded either hydrazone derivatives [RuCl(eta(6)-p-cymene){NH2N=C(CH3)(2)}L]BPh4 (5,6) [L=P(OMe)(3), P(OEt)(3)] or kappa(1)-azine complex [RuCl(eta(6)-p-cymene){kappa(1)-[N=C(CH3)(2)]N=C(CH3)(2)}(PiPr(3))]BPh4 (7). Cyclopentadienyl derivatives [Ru(eta(5)-C5H5){kappa(1)-[N=C(H)R1]-N=C(H)R1}(PPh3){P(OMe)(3)}](+) (10) [R1=Ph, 4-CH3C6H4, C2H5] were prepared by reacting the chloro compound RuCl (eta(5)-C5H5)(PPh3)[P(OMe)(3)] first with AgOTf and then with an excess of azine. Instead, treatment of RuCl(eta(5)-C5H5)(PPh3)[P(OMe)(3)] first with AgOTf and then with ketazine (CH3)(2)C=N-N=C(CH3)(2) in ethanol, yielded hydrazone derivative [Ru(eta(5)-C5H5){NH2N=C(CH3)(2)}(PPh3){P(OMe)(3)}]BPh4 (11). Oxidation of hydrazone derivative 11 with HgO gave dimethyldiazoalkane complex [Ru(eta(5)-C5H5){N2C(CH3)(2)}(PPh3){P(OMe)(3)}]BPh4 (13). The complexes were characterised by spectroscopy and X-ray crystal structure determination of [RuCl(eta(6)-p-cymene){kappa(1)-[N=C(H)Ph]-N=C(H)Ph}{P(OMe)(3)}]BPh4 (1a), [RuCl(eta(6)-p-cymene){kappa(1)-[N=C(H)Ph]-N=C(H)Ph}{P(OEt)(3)}]BPh4 (2a) and [Ru(eta(5)-C5H5){NH2N=C(CH3)(2)}(PPh3){P(OMe)(3)}]BPh4 (11).