SYNTHESIS, PHYSICAL-PROPERTIES, AND STRUCTURAL CHARACTERIZATION OF MU-CARBONATO-DICHLOROBIS(N,N,N',N'-TETRAMETHYL-1,3-PROPANEDIAMINE)DICOPPER(II), LCUCL(CO3)CLCUL, A DIAMAGNETIC INITIATOR FOR THE OXIDATIVE COUPLING OF PHENOLS BY DIOXYGEN

The reaction of N, N, N′,N′-tetramethyl-1, 3-propanediamine (L) with copper(I) chloride, carbon dioxide, and dioxygen in anhydrous methylene chloride gives a quantitative yield of the dinuclear μt-carbonato-dicopper(II) species LCUCl(CO3)ClCUL, which acts as an initiator for the oxidative coupling of phenols by dioxygen. This complex is diamagnetic and has been studied by spectroscopic methods and by a three-dimensional X-ray structural analysis. The complex crystallizes in the noncentrosymmetric orthorhombic space group P22l2lwith a = 8.0832 (15)Å, b = 11.6855 (14)Å, c = 11.9301 (17)Å,V= 1126.9 (3)Å3, andρ(calcd) = 1.528 g cm-3for mol wt 518.47 and Z = 2. Diffraction data were collected with a Syntex P21automated diffractometer, and the structure was solved by standard methods, resulting in RF= 2.90% and RWF= 3.07% for all 2232 reflections in the range 2θ = 3-50° (Mo Kα radiation). The molecule consists of two units of (Me2NCH2CH2CH2NMe2)CuCl which are bridged by a carbonate ligand. One oxygen atom of the carbonate ligand is bonded to both copper(II) ions (Cu-O(l) = Cu′-O(l) = 2.1527 (4)Å), while the other two oxygen atoms are each linked to one copper atom (Cu-0(2) = Cu′-0(2) ‘= 1.978 (2)Å). The molecule possesses precise C2symmetry and presumably owes its diamagnetic character to antiferromagnetic exchange across the almost linear Cu-0(1)-Cu′system (Cu-O(l)-Cu ′= 170.26 (13)°). © 1979, American Chemical Society. All rights reserved.