888408-68-2Relevant academic research and scientific papers
Tripodal bis(imidazole) thioether copper(I) complexes: Mimics of the CuM site of copper hydroxylase enzymes
Zhou, Lei,Powell, Douglas,Nicholas, Kenneth M.
, p. 7789 - 7799 (2008/10/09)
Tripodal bis(imidazole) thioether ligands, (N-methyl-4,5-diphenyl-2- imidazolyl)2C(OR)C(CH3)2SR′.(BIT OR,SR′; R = H, CH3; R′ = CH3, C(CH3)3, C(C6H5)3), have been prepared, offering the same N2S donor atom set as the Cu M binding site of the hydroxylase enzymes, dopamine beta hydroxylase and peptidylglycine hydroxylating monooxygenase. Isolable copper(I) complexes of the type [(BITOR,SMe)Cu(CO)]PF6 (3a and 3b) are produced in reactions of the respective tripodal ligands 1a (R = H) and 1b (R = Me) with [Cu(CH3CN)4]PF6 in CH2Cl2 under CO (1 atm); the pyramidal structure of 3a has been determined crystallographically. The infrared (IR) ν(CO)'s of 3a and 3b (L = CO) are comparable to those of the CuM-carbonylated enzymes, indicating similar electronic character at the copper centers. The reaction of [(BIT OH,SMe)Cu(CH3CN)]PF6 (2a) with dioxygen produces [(BITO,SOMe)2-Cu2(DMF) 2](PF6)2 (4), whose X-ray structure revealed the presence of bridging BIT-alkoxo ligands and terminal -SOMe groups. In contrast, oxygenation of 2b (R = Me) affords crystallographically defined [(BITOMe,SMe)2Cu2(μ-OH)2](OTf) 2 (5), in which the copper centers are oxygenated without accompanying sulfur oxidation. Complex 5 in DMF is transformed into five-coordinate, mononuclear [CuII(BITOMe,SMe)(DMF) 2](PF6)2 (6). The sterically hindered BIT OR,SR′- ligands 9 and 10 (R′ = t-Bu; R = H, Me) and 11 and 12 (R′ = CPh3; R = H, Me) were also prepared and examined for copper coordination/oxygenation. Oxygenation of copper(I) complex 13b derived from the BITOMe,SBu-t ligand is slow, relative to 2b, producing a mixture of (BITOMe,SBu-t)2Cu 2(μ-OH)2-type complexes 14b and 15b in which the -SBu-t group is uncoordinated; one of these complexes (15b) has been ortho-oxygenated on a neighboring aryl group according to the X-ray analysis and characterization of the free ligand. Oxygenation of the copper(I) complex derived from BIT OMe,SCPh3 ligand 12 produces a novel dinuclear disulfide complex, [(BITOMe,S)2-Cu2(μ-OH)2](PF 6)2 (17), which is structurally characterized. Reactivity studies under anaerobic conditions in the presence of t-BuNC indicate that 17 is the result of copper(I)-induced detritylation followed by oxygenation of a highly reactive copper(I)-thiolate complex.
Tripodal bis(imidazole) thioether copper(I) complexes: Mimics of the Cu(B) site of hydroxylase enzymes
Zhou,Powell,Nicholas
, p. 3840 - 3842 (2008/10/09)
Tripodal bis(imidazole) thioether ligands and the corresponding copper(I) complexes [(BIMT-OR)Cu(L)]PF6 [L = CH3CN (2), CO (3); R = H (a), CH3 (b)] have been prepared as models for the Cu(B) site of copper hydroxylase enzymes. The IR ν(CO) values of 3a and 3b (L = CO) are comparable to those of the carbonylated enzymes. The reaction of 2a with O 2 gives dinuclear complex 4 with bridging BIMT-O ligands and oxidized -SMe groups, whereas oxygenation of 2b affords [(BIMT-OMe)2Cu 2O(H)2](CF3SO3)2 (5) and Cu(BIMT-OMe)(DMF)2](PF6)2 (6).
