X-Ray crystal structure of chloro(cyclo-octa-1,5-diene)[4-dimethylamino-2-methyl(nitroso)benzene-N′]rhodium(I) and a nuclear magnetic resonance study of nitroso-rhodium co-ordination

Abstract

Complexes [RhCl(cod)L][cod = cyclo-octa-1,5-diene; L = 4-dimethylamino(nitroso)benzene or 4-dimethylamino-2-methyl(nitroso)benzene] have been prepared. On the basis of the temperature-dependent ¹H and ¹³C n.m.r. spectra of these complexes and of a mixture of [{RhCl(cod)}₂] and 4-dimethylamino-2,6-dimethyl(nitroso)benzene in [²H₁]chloroform, the nitroso nitrogen–rhodium bonding is discussed and thermodynamic parameters for the dissociation equilibria of the complexes [RhCl (cod)L] have been determined. A single-crystal X-ray structure analysis has been performed for [RhCl (cod)(2-Me-4-Me₂NC₆H₃NO)]. The crystals are triclinic, space group P, with Z= 2, a= 11.431 (6), b= 9.305 (6), c= 8.429(3)Å, α= 89.28(5), β= 82.24(4), and γ= 103.15(5)°. Block-diagonal least-squares refinement based on 4 405 independent reflections with |F₀| > 3 σ(F) converged at R= 0.043. The geometry around the rhodium atom is square planar with co-ordination of the nitroso-nitrogen and chlorine atoms as well as two cod olefin bonds.