TY - JOUR
T1 - Doubly phenoxide-bridged binuclear copper(II) complexes with ono tridentate schiff base ligand
T2 - Synthesis, structural, magnetic and theoretical studies Dedicated to Dr. Claude Lapinte for his outstanding contribution to organometallic molecular wires.
AU - Novoa, Néstor
AU - Justaud, Frédéric
AU - Hamon, Paul
AU - Roisnel, Thierry
AU - Cador, Olivier
AU - Le Guennic, Boris
AU - Manzur, Carolina
AU - Carrillo, David
AU - Hamon, Jean René
N1 - Funding Information:
The authors thank Drs. M. Fuentealba (PUC Valparaíso) and P. Jehan (CRMPO, Rennes) for helpful assistance and discussion with DFT calculations and HRMS measurements, respectively. This research has been performed as part of the Chilean-French International Associated Laboratory for “Inorganic Functional Materials” (LIAMIF-CNRS No. 836). Financial support from the Fondo Nacional de Desarrollo Científico y Tecnológico [FONDECYT (Chile), grant No. 1130105 (D.C., C.M. and M. F.)], the Vicerrectoría de Investigación y Estudios Avanzados, Pontificia Universidad Católica de Valparaíso, Chile (D.C., C.M. and M. F.), the CNRS and the Université de Rennes 1 is gratefully acknowledged. N.N. Thanks the CONICYT (Chile) and BECAS-CHILE for support of a graduate and Joint Supervision Scholarship (PUCV/UR1) and the Rennes Metropole for the 2013 scholarship awarded doctoral internship.
Publisher Copyright:
© 2014 Elsevier Ltd. All rights reserved.
PY - 2015/1/28
Y1 - 2015/1/28
N2 - The tridentate ONO-donor Schiff base ligand H2L, derived from the condensation of 1-anisyl-1,3-butanedione and 2-aminophenol, was generated in situ and reacted with Cu(NO3)2·3H2O to yield two doubly phenoxo bridged di-copper(II) complexes depending on the nitrogenous base used. [Cu2L2] (1) is obtained in 85% and 75% yield in the presence of pyridine or 4-picoline, respectively, and [(py-tBu)2Cu2L2] (2) is isolated in 75% yield in the presence of 4-tert-butylpyridine. Compounds 1 and 2 were characterized in the solid-state by elemental analysis and FT-IR spectroscopy. Single crystal X-ray diffraction study reveals that in 1 the two four-coordinated copper atoms adopt a square planar geometry, whereas in 2 each Cu(II) metal ion shows a five coordinate square pyramidal (ONO,N + O) geometry. In each dimer, two μ-phenolic oxygen atoms bridge the two half-units forming a planar Cu2O2 core. EPR studies in fluid solutions indicate that the dimeric structure of 1 and 2 is destroyed upon dissolution. In the solid-state, 1 is EPR silent, whereas 2 presents an unresolved broad resonance (ΔH peak-to-peak = 71.5 G) with g = 2.071 at 298 K, along with the triplet state (S = 1) signature at g = 4.181. Variable temperature (2-300 K) magnetic susceptibility measurements exhibit strong antiferromagnetic interactions between the Cu(II) centers with a J value of -397 cm-1 for 1, while no interaction operates between the two spins localized on Cu(II) metal ions in 2. Ab initio calculations were also performed to supplement the experimental results.
AB - The tridentate ONO-donor Schiff base ligand H2L, derived from the condensation of 1-anisyl-1,3-butanedione and 2-aminophenol, was generated in situ and reacted with Cu(NO3)2·3H2O to yield two doubly phenoxo bridged di-copper(II) complexes depending on the nitrogenous base used. [Cu2L2] (1) is obtained in 85% and 75% yield in the presence of pyridine or 4-picoline, respectively, and [(py-tBu)2Cu2L2] (2) is isolated in 75% yield in the presence of 4-tert-butylpyridine. Compounds 1 and 2 were characterized in the solid-state by elemental analysis and FT-IR spectroscopy. Single crystal X-ray diffraction study reveals that in 1 the two four-coordinated copper atoms adopt a square planar geometry, whereas in 2 each Cu(II) metal ion shows a five coordinate square pyramidal (ONO,N + O) geometry. In each dimer, two μ-phenolic oxygen atoms bridge the two half-units forming a planar Cu2O2 core. EPR studies in fluid solutions indicate that the dimeric structure of 1 and 2 is destroyed upon dissolution. In the solid-state, 1 is EPR silent, whereas 2 presents an unresolved broad resonance (ΔH peak-to-peak = 71.5 G) with g = 2.071 at 298 K, along with the triplet state (S = 1) signature at g = 4.181. Variable temperature (2-300 K) magnetic susceptibility measurements exhibit strong antiferromagnetic interactions between the Cu(II) centers with a J value of -397 cm-1 for 1, while no interaction operates between the two spins localized on Cu(II) metal ions in 2. Ab initio calculations were also performed to supplement the experimental results.
KW - Ab initio calculation
KW - Copper(II)
KW - Magnetic properties
KW - ONO
KW - Schiff base ligand
KW - Structure determination
KW - Tridentate
UR - http://www.scopus.com/inward/record.url?scp=84920277759&partnerID=8YFLogxK
U2 - 10.1016/j.poly.2014.05.032
DO - 10.1016/j.poly.2014.05.032
M3 - Article
AN - SCOPUS:84920277759
VL - 86
SP - 81
EP - 88
JO - Polyhedron
JF - Polyhedron
SN - 0277-5387
ER -