Syntheses, Crystal Structures and Catalytic Performances of Two Cu Complexes with 1,10-Phenanthroline Ligand

Abstract

Two novel Cu complexes, [Cu(Ⅱ)(phen) 2 Br] 2 [Cu(Ⅰ) 4 Br 6 ] ( 1 ) and [Cu(Ⅱ)(phen) 2 Br]Br·CH 3 OH ( 2 ) (phen=1,10-phenanthroline), have been synthesized in alcohol and characterized by infrared spectroscopy, elemental analysis, thermal analysis, and X-ray diffraction single-crystal structure analysis. The structure of 1 with a Cu(Ⅰ)-Cu(Ⅱ) mixed valence can be described as a supramolecular network assembled via the combination of π - π interactions and C-H…Br hydrogen bonds. Its unit cell structure contains two [Cu(Ⅱ)(phen) 2 Br] + ions and one tetranuclear [Cu(Ⅰ) 4 Br 6 ] 2- ion; four Cu atoms in the [Cu(Ⅰ) 4 Br 6 ] 2- anion are at corners of a tetrahedron, and six bromine atoms bridging along its six sides constitute an octahedron. The complex 2 consists of [Cu(Ⅱ)(phen) 2 Br] + , Br - and CH 3 OH, and a supramolecular framework is formed by π - π interactions. When 1 and 2 were used as catalysts for the oxidative carbonylation of methanol to dimethyl carbonate (DMC), 2 exhibits a turnover number of only 5.9 for DMC, while the [Cu(Ⅰ) 4 Br 6 ] 2- anion in 1 provides a suitable environment for the oxidative carbonylation of methanol, and the turnover number for DMC are up to 54.7. CCDC: 1437662, 1 ; 1014482, 2 .