Synthesis and reactions of coordinatively unsaturated 16-electron chalcogenolate complexes, Ru(EAr) 2(η 6-arene) and cationic binuclear chalcogenolate complexes, [(η 6-arene) Ru(μ-EPh) 3 Ru(η 6-arene)]PF 6

Abstract

Coordinatively unsaturated 16-electron ruthenium-selenolate complexes (η 6-arene)Ru(Se-2,4,6-C 6H 2Me 3) 2 [arene = p=CH 3C 6H 4(CHMe 2) ( 5b), C 6Me 6 ( 5c)] have been prepared by treating [((η 6-arene)RuCl 2] 2 ( 1) with sodium salt of 2,4,6-trimethylphenyl-selenolate in methanol. The complexes 5 are compared with the thiolate complexes such as (η 6-arene)Ru(SAr) 2 [SAr = 2,6-dimethylbenzenethiolate ( 2), SAr = 2,4,6-tri(isopropyl)benzenethiolate ( 3), (SAr) 2 = 1,2-benzenedithiolate ( 4); arene = C 6H 6 ( a), p-CH 3C 6H 4(CHMe 2) ( b), C 6Me 6 ( c)], which have been recently prepared by us. However, the tellurolate analog has not been obtained in similar manner. These selenolate complexes are dark green, being ascribed to the LMCT band [pπ(Se)→ dπ *(Ru)]. The absorption bands of S are red-shifted compared to the thiolate complexes. In contrast to the bulky substituted chalcogenolate ligand system, the reaction of 1 with PhENa followed by the addition of KPF6 resulted in the formation of the cationic binuclear chalcogenolate complexes [(η 6-arene)Ru(μ-E-Ph) 3Ru(η 6-arene)](PF 6) [E=Se ( 7), E = Te ( 8); arene = p-CH 3C 6H 4(CHMe 2) ( b) C 6Me 6 ( c)]. Reactions of the 16-electron thiolate and selenolate complexes with σ-donor molecules such as DMSO, hydrazine and ammonia along with some electrophiles were investigated. DMSO can coordinate with the thiolate complex 2a to give a DMSO adduct of 9, which was characterized spectroscopically and crystallographically. The strength of complexation of hydrazine and ammonia to the thiolate and selenolate complexes 2, 3, 4c and 5 depends on the effective electron deficiency of the ruthenium supported by η 6-arene ligand and two chalcogenolate ligands. Two new hydrazine complexes (η 6-C 6H 6)Ru(η 1- NH 2)(S-2,6-C 6H 3Me 2) 2 ( 10a) and [(η 6-C 6Me 6)Ru(S 2C 6H 4)] 2(μ- NH 2 NH 2) ( 16) were crystallographically characterized. The observed two different coordination modes, mononuclear η 1-hydrazine and binuclear μ-hydrazine, were the results of the combined steric effect of the arene and the thiolate coligands as well as the NH …S hydrogen bonding.