Copper(I) carbonyl complexes with a series of hindered L R1,R2 ligands (L: hydrotris(pyrazolyl)borate, R1 and R2 are substituents at the 3-and 5-positions of the pyrazole ring, respectively), L R1,R2 CuCO [R1, R2 ) Me, Me (1), i-Pr, i-Pr (2), t-Bu, Me (3), t-Bu, i-Pr (4), Ph, i-Pr (5), Ph, Ph (6)] have been synthesized and characterized by 1 H NMR and IR spectroscopy and elemental analysis. The molecular structures of 3 and 6 have been determined by X-ray crystallography. The electronic structures of copper(I) sites are characterized by means of 63 Cu NMR spectroscopy and by the CtO stretching vibration. The sharp 63 Cu NMR signals are observed for L R1,R2 CuCO complexes in toluene at room temperature. The 63 Cu NMR signals of copper(I) complexes with alkyl-substituted ligands (1-4) are observed in lower field than those of the phenyl derivatives (5, 6) correlating with the electrondensity at the copper center. This argument is supported by the good correlation between the δ( 63 Cu) value and CtO stretching vibration which is a sensitive indicator of the extent of back-donation of the Cu d electrons to the antibonding CtO orbitals.

To clarify guidelines for a high-performance mixed conducting oxide anode, electrochemical behaviors of mixed conducting oxide anodes were studied on the oxides, La 0.

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New mononuclear nitratocopper(II) complexes ([Cu(NO3){HB(3,5-iPr2pz)3}] (1) and [Cu(NO3){HB(3-tBu-5-iPrpz)3}] (3)) and a novel mononuclear hydroxocopper(II) complex ([Cu(OH){HB(3-tBu-5-iPrpz)3}] (4)) have been prepared. These complexes were characterized by X-ray analysis and IR, UV-vis, and EPR spectroscopies. Except for the dinuclear complex ([{Cu[HB(3,5-iPr2pz)3]}2(μ-OH)2] (2)), the complexes are mononuclear structures having square-pyramidal (1), trigonal-pyramidal (3), and distorted tetrahedral (4) geometry. In comparison with these structures and their physicochemical properties, the structural effects on the alkyl substitutions at the close 3-position in hydrotris(pyrazolyl)borates play an important role in modifying the coordination environment about a copper(II) center and their physicochemical properties.

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