Copper Chemistry of -Diketiminate Ligands: Monomer/Dimer Equilibria and a New Class of Bis(
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- 作者：Douglas J. E. Spencer ; Anne M. Reynolds ; Patrick L. Holland ; Brian A. Jazdzewski ; Carole Duboc-Toia ; Laurent Le Pape ; Seiji Yokota ; Yoshimitsu Tachi ; Shinobu Itoh ; and William B. Tolman
- 刊名：Inorganic Chemistry
- 出版年：2002
- 出版时间：December 2, 2002
- 年：2002
- 卷：41
- 期：24
- 页码：6307 - 6321
- 全文大小：264K
- 年卷期：v.41,no.24(December 2, 2002)
- ISSN：1520-510X
文摘
A series of Cu(I) and Cu(II) complexes of a variety of 
ta2.gif" BORDER=0 ALIGN="middle">-diketiminate ligands (L-) with a range of substitutionpatterns were prepared and characterized by spectroscopic, electrochemical, and, in several cases, X-raycrystallographic methods. Specifically, complexes of the general formula [LCuCl]2 were structurally characterizedand their magnetic properties assessed through EPR spectroscopy of solutions and, in one instance, by variable-temperature SQUID magnetization measurements on a powder sample. UV-vis spectra indicated reversibledissociation to 3-coordinate monomers LCuCl in solution at temperatures above -55 
tities/deg.gif">C. The Cu(I) complexesLCu(MeCN) exhibited reversible Cu(I)/Cu(II) redox couples with E1/2 values between +300 and +520 mV versusNHE (cyclic voltammetry, MeCN solutions). These complexes were highly reactive with O2, yielding intermediatesthat were identified as rare examples of neutral bis(tities/mgr.gif">-oxo)dicopper complexes on the basis of their EPR silence,diagnostic UV-vis absorption data, and O-isotope-sensitive resonance Raman spectroscopic features. The structuralfeatures of the compounds [LCuCl]2 and LCu(MeCN) as well as the proclivity to form bis(tities/mgr.gif">-oxo)dicopper productsupon oxygenation of the Cu(I) complexes are compared to data previously reported for complexes of more stericallyhindered ta2.gif" BORDER=0 ALIGN="middle">-diketiminate ligands (Aboelella, N. W.; Lewis, E. A.; Reynolds, A. M.; Brennessel, W. W.; Cramer, C.J.; Tolman, W. B. J. Am. Chem. Soc. 2002, 124, 10600. Spencer, D. J. E.; Aboelella, N. W.; Reynolds, A. M.;Holland, P. L.; Tolman, W. B. J. Am. Chem. Soc. 2002, 124, 2108. Holland, P. L.; Tolman, W. B. J. Am. Chem.Soc. 1999, 121, 7270). The observed structural and reactivity differences are rationalized by considering the stericinfluences of both the substituents on the flanking aromatic rings and those present on the ta2.gif" BORDER=0 ALIGN="middle">-diketiminate backbone.
ta2.gif" BORDER=0 ALIGN="middle">-diketiminate ligands (L-) with a range of substitutionpatterns were prepared and characterized by spectroscopic, electrochemical, and, in several cases, X-raycrystallographic methods. Specifically, complexes of the general formula [LCuCl]2 were structurally characterizedand their magnetic properties assessed through EPR spectroscopy of solutions and, in one instance, by variable-temperature SQUID magnetization measurements on a powder sample. UV-vis spectra indicated reversibledissociation to 3-coordinate monomers LCuCl in solution at temperatures above -55 tities/deg.gif">C. The Cu(I) complexesLCu(MeCN) exhibited reversible Cu(I)/Cu(II) redox couples with E1/2 values between +300 and +520 mV versusNHE (cyclic voltammetry, MeCN solutions). These complexes were highly reactive with O2, yielding intermediatesthat were identified as rare examples of neutral bis(tities/mgr.gif">-oxo)dicopper complexes on the basis of their EPR silence,diagnostic UV-vis absorption data, and O-isotope-sensitive resonance Raman spectroscopic features. The structuralfeatures of the compounds [LCuCl]2 and LCu(MeCN) as well as the proclivity to form bis(tities/mgr.gif">-oxo)dicopper productsupon oxygenation of the Cu(I) complexes are compared to data previously reported for complexes of more stericallyhindered ta2.gif" BORDER=0 ALIGN="middle">-diketiminate ligands (Aboelella, N. W.; Lewis, E. A.; Reynolds, A. M.; Brennessel, W. W.; Cramer, C.J.; Tolman, W. B. J. Am. Chem. Soc. 2002, 124, 10600. Spencer, D. J. E.; Aboelella, N. W.; Reynolds, A. M.;Holland, P. L.; Tolman, W. B. J. Am. Chem. Soc. 2002, 124, 2108. Holland, P. L.; Tolman, W. B. J. Am. Chem.Soc. 1999, 121, 7270). The observed structural and reactivity differences are rationalized by considering the stericinfluences of both the substituents on the flanking aromatic rings and those present on the ta2.gif" BORDER=0 ALIGN="middle">-diketiminate backbone.