TY - JOUR
T1 - Copper chemistry of β-diketiminate ligands
T2 - Monomer/dimer equilibria and a new class of bis(μ-oxo)dicopper compounds
AU - Spencer, Douglas J.E.
AU - Reynolds, Anne M.
AU - Holland, Patrick L.
AU - Jazdzewski, Brian A.
AU - Duboc-Toia, Carole
AU - Le Pape, Laurent
AU - Yokota, Seiji
AU - Tachi, Yoshimitsu
AU - Itoh, Shinobu
AU - Tolman, William B
PY - 2002/12/2
Y1 - 2002/12/2
N2 - A series of Cu(I) and Cu(II) complexes of a variety of β-diketiminate ligands (L-) with a range of substitution patterns were prepared and characterized by spectroscopic, electrochemical, and, in several cases, X-ray crystallographic methods. Specifically, complexes of the general formula [LCuCl]2 were structurally characterized and 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 reversible dissociation to 3-coordinate monomers LCuCl in solution at temperatures above -55°C. The Cu(I) complexes LCu(MeCN) exhibited reversible Cu(I)/Cu(II) redox couples with E1/2 values between +300 and +520 mV versus NHE (cyclic voltammetry, MeCN solutions). These complexes were highly reactive with O2, yielding intermediates that were identified as rare examples of neutral bis(μ-oxo)dicopper complexes on the basis of their EPR silence, diagnostic UV-vis absorption data, and O-isotope-sensitive resonance Raman spectroscopic features. The structural features of the compounds [LCuCl]2 and LCu(MeCN) as well as the proclivity to form bis(μ-oxo)dicopper products upon oxygenation of the Cu(I) complexes are compared to data previously reported for complexes of more sterically hindered β-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 steric influences of both the substituents on the flanking aromatic rings and those present on the β-diketiminate backbone.
AB - A series of Cu(I) and Cu(II) complexes of a variety of β-diketiminate ligands (L-) with a range of substitution patterns were prepared and characterized by spectroscopic, electrochemical, and, in several cases, X-ray crystallographic methods. Specifically, complexes of the general formula [LCuCl]2 were structurally characterized and 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 reversible dissociation to 3-coordinate monomers LCuCl in solution at temperatures above -55°C. The Cu(I) complexes LCu(MeCN) exhibited reversible Cu(I)/Cu(II) redox couples with E1/2 values between +300 and +520 mV versus NHE (cyclic voltammetry, MeCN solutions). These complexes were highly reactive with O2, yielding intermediates that were identified as rare examples of neutral bis(μ-oxo)dicopper complexes on the basis of their EPR silence, diagnostic UV-vis absorption data, and O-isotope-sensitive resonance Raman spectroscopic features. The structural features of the compounds [LCuCl]2 and LCu(MeCN) as well as the proclivity to form bis(μ-oxo)dicopper products upon oxygenation of the Cu(I) complexes are compared to data previously reported for complexes of more sterically hindered β-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 steric influences of both the substituents on the flanking aromatic rings and those present on the β-diketiminate backbone.
UR - http://www.scopus.com/inward/record.url?scp=0037010964&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037010964&partnerID=8YFLogxK
U2 - 10.1021/ic020369k
DO - 10.1021/ic020369k
M3 - Article
C2 - 12444774
AN - SCOPUS:0037010964
SN - 0020-1669
VL - 41
SP - 6307
EP - 6321
JO - Inorganic chemistry
JF - Inorganic chemistry
IS - 24
ER -