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Title: Synthesis, characterization, and x-ray molecular structures of mono- and dinuclear copper complexes with 2,7-bis(2-pyridyl)-1,8-naphthyridine

Journal Article · · Inorg. Chem.; (United States)
DOI:https://doi.org/10.1021/ic00190a041· OSTI ID:5943087

The preparation and characterization of two complexes of 2,7-bis(2-pyridyl)-1,8-naphthyridine (bpnp) with copper(II) and copper(I) are described. The X-ray molecular structure of a mononuclear Cu(I) complex, (Cu(bpnp)(bis-triphenylphosphine)PF/sub 6/, was determined with full-matrix least-squares procedures to a final R index of 0.057. Crystals are monoclinic, space group P2/sub 1//n, with cell dimensions a = 14.855 (6) A, b = 21.914 (8) A, c = 15.111 (2) A, and V = 4862.651 A/sup 3/ with Z = 4. The X-ray molecular structure of the dinuclear complex (Cu/sub 2/(bpnp)(..mu..-Cl)(..mu..-OH)Cl/sub 2/) was also determined to a final R index of 0.0363. The crystals are monoclinic, space group P2/sub 1//m, with cell dimensions a = 7.694 (1) A, b = 16.434 (2) A, c = 7.921 (1) A, and V = 952.695 A/sup 3/ with Z = 2. In the latter complex, each Cu(II) ion is chelated by a 2,2'-bipyridine fragment of the bpnp and the two metal ions are linked by bridging chlorine and oxygen atoms. The Cu-Cu distance is 3.022 A. The coordination geometry about each Cu(II) is discussed. Magnetic susceptibility measurements of the paramagnetic complex suggest a weak antiferromagnetic interaction (absolute value 2J < 200 cm/sup -1/, room-temperature magnetic moment/Cu = 1.64 ..mu../sub B/), which couples the spins of the two unpaired electrons. Cyclic voltammograms of this complex in aqueous solution show reduction occurs in two one-electron transfers (E/sub 1/2/ = 0.36, 0.16 V vs. Ag/AgCl). X-ray photoelectron spectroscopy allows differentiation of bridging vs. terminal chlorine atoms with peaks at 197.2 (5) and 196.2 (2) eV, respectively. Preliminary studies show that in situ reduction of the bpnp copper(II) dimer gives solutions of bpnp copper(I) dimers that reversibly coordinate carbon monoxide. 30 references, 3 figures, 6 tables.

Research Organization:
Univ. of California, Santa Barbara
DOE Contract Number:
AC03-76SF00098
OSTI ID:
5943087
Journal Information:
Inorg. Chem.; (United States), Vol. 23:22
Country of Publication:
United States
Language:
English