Synthesis of diruthenium(II,III) amidate compounds. Crystal structure of [RU2(mu-HNOCC4H3S)(4)(thf)(2)]SbF6 center dot 0.5cyclohexane

The reaction of Ru2Cl(mu -O2CMe)(4) with amides in 2-methoxyethanol affords the compounds Ru2Cl(mu -HNOCR)(4) [R = C6H3-3,5-(OMe)(2) (1), C6H4-p-OMe ( 2), C6H4-p-CMe3 (3), C4H3S (4). cyclo-C6H11, (5), CMe3 (6)]. The reaction o f 1-6 with AgBF4 and AgSbF6 gives [Ru-2(mu -HNOCR)(4)(thf)(2)]BF4 [R = C6H3 -3,5-(OMe)(2) (7), C6H4-p-OMe (8), C6H4-p-CMe3 (9), C4H3S (10), cyclo-C6H11 (11), CMe3 (12)] and [Ru-2(mu -HNOCR)(4)(thf)(2)]SbF6 [R = C6H3-3,5-(OMe)( 2) (13), C6H4-p-OMe (14), C6H4-p-CMe3 (15), C4H3S (16). cyclo-C6H11 (17), C Me3 (18)], respectively. The structure of complex 16.0.5cyclohexane has bee n determined by X-ray crystallography. The Ru-Ru bond distance in the [Ru-2 (mu -HNOCC4H3S)(4)(thf)(2)](+) unit is 2.286(2) Angstrom. A magnetic study, in the 2-300 K temperature range, of the compounds is described. Complexes 1-18 show a large zero-field splitting which varies from 43 to 71 cm(-1). These complexes also show a weak, but not negligible intermolecular antifer romagnetic coupling (zJ from -0.1 to - 2.9 cm (-1)). These antiferromagneti c exchanges have not been observed previously in the amidate complexes. (C) 2001 Elsevier Science Ltd. All rights reserved.