Ligating properties of thionitrosoamines. IV. Cationic complexes of rhodium(I), rhodium(III), and ruthenium(II) containing N-thionitrosodimethylamine

The solvento species obtained by treatment of the complexes [Rh(1,5-cyclooctadiene)Cl]2, [Rh(norbornadiene)Cl]2, [Rh(CO)2Cl]2, C5H5Rh(CO)I2, [C5Me5RhCl2]2, and [Ru(C6H6)Cl2]2 with AgPF6 in acetone or acetonitrile react with a large excess of Me2NNS to give the compounds [Rh(1,5-C8H12)-(SNNMe2)2]PF6 (1a), [Rh(C7H8)(SNNMe2)2]PF6 (1b), [Rh(CO)2(SNNMe2)2]PF6 (2), [C5H5Rh(SNNMe2)3](PF6)2 (3), [C5Me5Rh(SNNMe2)3](PF6)2 (4), and [Ru(C6H6(SNNMe2)3](PF6) (5). If the thionitroso ligand is not preent in large excess decomposition often occurs. The use of AgClO4 allows isolation of the perchlorate salts of 1a, 1b, 2, 4, and 5, and the complexes [C5H5Rh-(SNNMe2)2(ClO4)ClO4 (6) and Rh(1,5-C8H12)(SNNMe2)(ClO4) (7). In the H1 NMR spectra the methyl protons of Me2NNS are observed as two quadruplets, in the range δ 3.75-4.25 (4J(HH) ca. 0.7 Hz) because of restricted rotation around the NN bond. The rhodium(I) complexes (1a, 1b, and 2) reacts with PPh3 or p-tolylPPh2 to give labile products, and only [Rh(1,5-C8H12)(SNNMe2)(PPh3)]ClO4 (8) and [Rh(1,5-C8H12)(SNNMe2)(p-tolylPPh2)]ClO4 (9) were isolated and characterized.