Dinuclear Cu(I) Complexes of 1,2,4,5-Tetra(7-azaindolyl)benzene: Persistent 3-Coordinate Geometry, Luminescence, and Reactivity

Citations Over TimeTop 13% of 2006 papers

Abstract

Five Cu(I) complexes [Cu2(ttab)(CH3CN)2][BF4]2 (1), [Cu(2)(ttab)(PPh3)2][BF4]2 (2), [Cu2(ttab)I2] (3), [Cu2(ttab)(I3)2] (4), and [Cu2(ttab)(I)BF4]n (5) with 1,2,4,5-tetra(7-azaindolyl)benzene (ttab) have been synthesized and characterized. The structures of compound 1, 2, 4, and 5 have been determined by single-crystal X-ray diffraction analyses, which established that 1, 2, and 4 are discrete dinuclear Cu2 compounds while compound 5 is a 1D coordination polymer with the I- ligand bridging two dinuclear Cu2 units. The ttab ligand in all four complexes adopts a 1,3-chelation mode. The Cu(I) center in all complexes is three-coordinate. Close contact between the Cu(I) center and the benzene ring in the ttab ligand was observed in all four structures, which is believed to play a role in stabilizing the three-coordinate geometry of the Cu(I) center. The crystals of 1, 2, and 5 contain channels in the lattice that host solvent molecules such as CH2Cl2 and toluene. Fluorescent measurements established that, in solution, compounds 1-3 display weak blue luminescence which originates from the ttab but is significantly red-shifted and has a much lower emission intensity, compared to the free ttab ligand. The application of compound 1 in C-N cross-coupling reactions was examined by using the reaction of phenyl halides with imidazole as a model system. For the reaction with phenyl iodide, 1 was found to be as effective a catalyst as the CuI/1,10-phenanthroline system. For the reaction with phenyl bromide, 1 is less effective than the CuI/1,10-phenanthroline system. Compound 1 reacts with O2 gas, as established by UV-vis spectra, but the oxidized products have not been characterized.

Related Papers

• → Synthesis of di- and tetra-substituted 1,4,5,8-tetra-azaphenanthrenes (pyrazino[2,3-f]quinoxalines)(1975)25 cited
• → MNDO study of tetra-tert-butyltetrahedrane and tetra-tert-butylcyclobutadiene and of their thermal interconversion(1979)33 cited
• → Synthesis of New Tetrakis N-Substituted Tetra-Azamacrocycles(1998)5 cited
• → The crystal and molecular structure of tetra-μ-chloro-tetra-μ-ethyloxycarbene-di- μ3-hydroxo dodecacarbonyl-di-chloro-hexaruthenium(II)(1978)15 cited
• → ChemInform Abstract: SYNTHESIS AND STEREOCHEMISTRY OF TETRA‐O‐TOLYLETHENE AND 1,1,2,2‐TETRA‐O‐TOLYLETHANE(1983)