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 - 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
SN - 0277-5387
VL - 86
SP - 81
EP - 88
JO - Polyhedron
JF - Polyhedron
ER -