Varshavsky, Yu. S., Cherkasova, T. G., Galding, M. R., Korlyukov, A. A., Podkorytov, I. S., Gindin, V. A., Smirnov, S. N., Mazur, A. S. & Rubaylo, A. I. 13C NMR spectrum of crystalline [Rh(Acac) (CO)2]: A contribution to the discussion on [Rh(Acac) (CO)2] molecular structure in the solid state. Journal of Organometallic Chemistry 874, 70–73 (2018).
DOI: 10.1016/j.jorganchem.2018.08.009
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⋯HC 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 Å, the distances OC are 3.65 and 5.00 Å, the angles OHC are 164.9° and 126.4°.
Tags: Podkorytov