153217-22-2Relevant academic research and scientific papers
Octahedral d6 bis(maleimide) and bis(maleic anhydride) complexes of molybdenum
Lai, Chen-Hsing,Cheng, Chien-Hong,Liao, Fen-Ling,Wang, Sue-Lein
, p. 5658 - 5664 (2008/10/08)
Mo(CO)3(CH3CN)3 reacts with 2 equiv of alkene, where the alkene is maleimide (MI), N-phenylmaleimide (PhMI), or N-methylmaleimide, to give the corresponding Mo(CO)2(alkene)2(CH3CN)2 complex (1a-c, respectively) in excellent yield. Dissolution of 1 in DMSO led to the substitution of acetonitrile ligands by DMSO to form the corresponding cis bis(DMSO) complexes 2a-c. Addition of 1 equiv of NN to 1 yields Mo(CO)2(alkene)2(NN) (NN = en, alkene = PhMI (3b), MeMI (3c); NN = o-phenylenediamine, alkene = PhMI (4b)). Treatment of Mo-(CO)4(NN), where NN = phen or bpy, with 2 equiv of alkene in refluxed acetonitrile for 2 h gave Mo(CO)2-(alkene)2(NN) (NN = phen, alkene = MI (5a), PhMI (5b); NN = bpy, alkene = MI (6a), PhMI (6b)). Treatment of Mo(CO)3(CH3CN)3 with 2 equiv of maleic anhydride (MA) gave Mo(CO)2(MA)2(CH3CN)2 (7). The acetonitrile ligands in 7 were replaced by DMSO molecules to give complex 8 as 7 was dissolved in DMSO. Similarly, the reaction of 7 with a bidentate ligand NN (phen or bpy) gave the substituted product Mo(CO)2(MA)2(NN) (9 or 10). The structures and conformations of 1b and 7 were determined by X-ray diffraction. Both molecules adopt an octahedral geometry with mutually perpendicular trans alkene ligands and each alkene ligand eclipses a N-Mo-CO vector. Each PhMI or MA is oriented so that the central nitrogen or oxygen atom points to a carbonyl group. 1b crystallizes in triclinic space group P1 with unit cell parameters a = 10.110(3) ?, b = 11.607(3) ?, c = 12.278(3) ?, β = 76.61(2)°, and Dc = 1.512 g cm-3 for Z = 2; least-squares refinement based on 2839 independent observed reflections produced final R and Rw values of 0.041 and 0.038, respectively. Compound 7 belongs to orthorhombic space group Pbcn with unit cell parameters a = 9.493(3)?, b = 12.954(5)?, c = 13.460(6)?, and Dc = 1.726 g cm-3 for Z = 4; after refinement, the final R and Rw values were 0.023 and 0.026, respectively, on the basis of 1027 independent observed reflections. There are three possible conformations for a trans bis(maleimide) or bis(maleic anhydride) complex (I-III). The results of X-ray and NMR studies indicate that the main conformation of complexes 1-10 is I both in the solid state and in solution.
