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13C MAS NMR spectrum of polycrystalline [Rh(Acac) (CO)2] (1) displays separate signals from all 7 carbon atoms: 2 doublets from CO ligand carbons along with 5 singlets from Acac carbons. GIPAW calculation of 13C shielding tensor values also revealed non-equivalence of all carbon atoms in molecule 1 in the anisotropic medium of the crystal lattice. Apparently, the C2v symmetry of molecule 1 is broken owing to the asymmetry of its contacts to the neighboring molecules. For example, the contacts O⋯H C of two CO ligands of molecule 1 to the CH group of the closest molecule in the adjacent stack are markedly different: the distances OH are 2.72 and 4.38 A, the distances OC are 3.65 and 5.00 A, the angles OHC are 164.9° and 126.4°.

A new rhodium(I) dimethyl sulfoxide (DMSO) 8-oxyquinolinato (Oxq) complex, [Rh(Oxq)(CO)(DMSO)] ( I ), has been prepared and characterized by IR, 1 H and 13 C NMR, and X-ray data. DMSO is S-coordinated in the trans -N position. The values of ν(CO), carbonyl δ 13 С, as well as δ 13 С and δ 1 H of Oxq ligand for three L trans -N complexes, [RhOxq(CO)(L)] (L = NH 3 , DMSO, and CO), define the intermediate position of DMSO within the ligand L series ranged in their net donating potency. Observed spin–spin couplings of Oxq 13 C (C2, C3, C4a, C7, C8a) and 1 H (H2) nuclei to 103 Rh provide one more tool to study long-range interactions of Oxq rings with metallocenter and remote ligand L.

Trans-[RuPy4(CN)2 cleaves chloro-rhodium bridges in rhodium(I) binuclear complexes, [Rh(CO)2Cl]2, [Rh(Cod)Cl]2, and [(Cod)RhCl2Rh(CO)2] yielding heterometallic triad complexes, [(CO)2ClRh(NC)RuPy4(CN)RhCl(CO)2] (I), [(Cod)ClRh(NC)RuPy4(CN)RhCl(Cod)] (II), and [(Cod)ClRh(NC)RuPy4(CN)RhCl(CO)2] (III), respectively. In solutions, III coexists with equilibrium amounts of I and II in the near-binomial proportions. Under action of [Rh(CO)2Cl]2, II transforms into I with parallel formation of [Rh(Cod)Cl]2. Ligand effect transmission along the L-Rh-NC-Ru-CN-Rh-L′ chain is studied by 1H and 13C NMR. Chemical shifts δ1H and δ13C of Ru-bound Py ligands are sensitive to the nature of Rh-bound ligands. Values of δ1H and δ13C of Cod and 13C of CO ligands are sensitive to the ligands at the remote end of the L-Rh-NC-Ru-CN-Rh-L′ chain. Reaction of trans-[RuPy4(CN)2] with Rh2(OAc)4 yields an apparently linear polymer [-Rh(OAc)4Rh-NCRuPy4CN-]. Upon action of [Rh(CO)2Cl]2, the polymer decomposes yielding I and Rh2(OAc)4. X-ray structure data for I are given.

Selective oxidation of one (trans to N) carbonyl group in [Rh(8-Oxiquinolinato)(CO)2] with stoichiometric amount of Me3NO in MeCN produces a solution containing [Rh(Oxq)(CO)(Me3N)] and [Rh(Oxq)(CO)(MeCN)]. The ammonia complex, [Rh(Oxq)(CO)(NH3)], has been prepared by action of NH3 gas on this solution and characterized by IR, 1H and 13C NMR, and X-ray data. Spectral parameters, ν(CO), δ 13C, and 1J(CRh), were measured in situ for a series of complexes [Rh(Oxq)(CO)(L)] (L = NAlk3, Py, PBu3, PPh3, P(OPh)3, C8H14) formed upon action of L on [Rh(Oxq)(CO)(NH3)] in THF. A new ν(CO) and δ 13C based scale of σ-donor/π-acceptor properties of ligands L is proposed including NH3 and CO as the natural endpoints.