. Can. J. Chem. 66, 1123Chem. 66, (1988. Two crystalline modifications (I and 11) of diethylammonium trans-tetrachlorobis(dimethylsulfoxide-S)rhodate(III) have been isolated from the same reaction mixture. The compound is formed by hydrolysis, in the presence of hydrochloric acid, of an ql-ylidic enamine complex of rhodium(III), which is made via dehydrogenation of triethylamine in the presence of mertrichlorotris(dimethylsulfoxide)rhodium(III). Crystals of form1 are tricbnic, a = 8.1787(7), b = 10.761(1), c = 10.927(1) A, ci = 86.681(6), P = 84.879(7), y = 71.8 14(8)", Z = 2, space group P1, and those of form I1 are_ triclinic, a = 7.931(2), b = 9.489(2), c = 13.302(2) A, ci = 102.03(1), P = 97.40(1), y = 107.49(1)", Z = 2, space group P1.
tetrachlorobis(dimethylsulfoxide-S)rhodate(III) anion within 2is 0-bonded (Me2SO) and two are S-bonded (Me2SO) (1,2). In has been characterized by X-ray analysis previously, but in the case of triethylamine, the dehydrogenation yields an enaassociation with a sodium cation (3) nmr spectra were recorded on Bruker WP80 or Varian XLlOO instruComplex 1 exists in two forms, the mer-trans ( l a ) and the mer-cis (lb); both were isolated and the latter was characterized by X-ray analysis (1). On studying the solution chemistry of these complexes, we discovered an acidiflcation/hydrolysis reaction, [2]; subsequent characterization of product 2 by X-ray analysis showed it to exist in two distinct forms which differ in H-bonding interactions between the diethylammonium cation and the anion, which has trans geometry.mentioperating in the FT mode with TMS as internal standard. Infrared spectra were recorded on a Perkin-Elmer 598 or on a Nicolet 5DX FT spectrometer. Elemental analyses were performed by Mr. P. Borda of this department. Syntheses of n~er-RhCl~(Me~SO)~ and RhC13(Me2S0)2(CH2CH= NEt2), 1, followed literature procedures (1). Dimethylacetamide hydrochloride (DMA.HC1) was prepared by passing gaseous HCl through neat DMA, and recrystallizing the white adduct formed from ethanol (5).[Cation] trans-[RhCl4(Me2SO)z], cation = NEBH', N E~~H~' (2) (a) RhC13(Me2S0)3 (200 mg, 0.45 mmol) and NEt3 (0.2 mL, 1.4 mmol) were stirred in acetone (25 mL) under Ar overnight, and the solution concentrated to give an off-white precipitate (NEt3-HCl) and a red-brown solution -which at this stage contains 1 (1). Addition of DMA-HCI (1 80