Bis(aryldiazene)- and Related Mono (aryldiazenido) ruthenium Complexes: Preparation, Characterization, and Reactivity. Crystal Structure of [Ru(4-CH3C6H4N=NH)2{P(OEt)3}4](PF6)2

Complexes [Ru(ArN=NH)2L4](BPh4)2 (1) and [RuH(ArN=NH)L4]BPh4 (2) [L = P(OEt)3; Ar = C6H5, 4-CH3C6H4, 4-CH3OC6H4, 4-FC6H4, 2,6-Cl2C6H3, 2,3-Cl2C6H3] were synthesized by allowing the hydride RuH2[P(OEt)3]4 to react with aryldiazonium cations; their characterization by 1H and 31P(1H) NMR (with 15N isotopic substitution) is reported. Atom connectivity in the cation [Ru(4-CH3C6H4N=NH)2(P(OEt)3)4]2+ is determined by a low-precision X-ray structure determination of its PF6- salt. Crystals are monoclinic, space group P21/n, with unit cell dimensions a = 23.319 (3) Å,b = 22.328 (3) Å, c = 11.513 (2) Å, β = 91.93 (1)°, and Z = 4. The structure was solved by heavy-atom methods and refined by least squares to an R index of 0.0969. The geometry around the ruthenium atom is essentially octahedral with the two diazene ligands in cis positions. The reaction of the bis(aryldiazene) derivatives 1 with NEt3 leads to new pentacoordinate aryldiazenido [Ru-(ArN2)(P(OEt)3)4]+ (3; Ar = C6H5, 4-CH3C6H4, 4-FC6H4) complexes. Protonation reactions with HBF4 and CF3COOH of these aryldiazenido compounds 3 afforded [Ru(ArN=NH){P(OEt)3}4](BPh4)2 and [Ru(CF3COO)(ArN=NH){P(OEt)3}4]BPh4 (Ar = 4-CH3C6H4) derivatives, respectively. Lastly, a new series of ruthenium(II) complexes of the types trans-[Ru(ArN=NH)-(CO)L4]2+, cis- and trans-[RuCl(CO)L4]+, [Ru(ArN=NH)L5]2+, [RuCl(4-CH3C6H4NC)2L3]+, [Ru(4-CH3C6H4NC)3L3]2+, and cis-[RuCl(4-CH3C6H4N=NH)L4]+ (Ar = 4-CH3C6H4) were prepared by ligand-substitution reaction of both 1 and 2 derivatives. Their characterization by infrared and 1H and 31P{1H) NMR spectra is also reported. © 1988, American Chemical Society. All rights reserved