New Rh(III) complexes of 5‐methyl‐5‐(pyridyl)‐2,4‐imidazolidenedione: Synthesis,X‐ray structure,electrochemical study and catalytic behaviour for hydrogenation of ketones |
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Abstract: | We describe the reaction of anion RhCl6]3? with a series of hydantoin ligands (HL1, HL2 and HL3 = 5‐methyl‐5‐(2‐, 3‐ and 4‐pyridyl)‐2,4‐imidazolidenedione, respectively). Based on spectroscopic, cyclic voltammetric, elemental and MS analyses, the complexes have the general formula KRhCl2(L1)2] ( 1 ), cis ‐ and trans ‐KRhCl4(HL2)2] ( 2a and 2b ) and cis ‐ and trans ‐KRhCl4(HL3)2] ( 3a and 3b ). Complexes 2a , 2b , 3a and 3b were characterized successfully using infrared, 1H NMR and 13C NMR spectral analyses. Dissolution of complex 1 in dimethylsulfoxide (DMSO) led to elimination of one KL1 ligand and coordination of two DMSO molecules as ligands and transformation of this complex to cis ‐ and trans ‐RhCl2L1(DMSO)2] ( 1a and 1b ). Recrystallization led to separation and isolation of crystals of 1a from the initial mixture. X‐ray analysis results showed that this complex was crystallized as solvated complex cis ‐RhCl2L1(DMSO)2]DMSO. The catalytic activity of these complexes was then evaluated for the hydrogenation of various ketones. |
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Keywords: | electrochemical study hydrogenation Rh(III) complexes spectroscopy synthesis X‐ray structure |
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