TY - JOUR
T1 - Redox-switching of ternary Ni(II) and Cu(II) complexes
T2 - Synthesis, experimental and theoretical studies along with second-order nonlinear optical properties
AU - Novoa, Néstor
AU - Manzur, Carolina
AU - Roisnel, Thierry
AU - Dorcet, Vincent
AU - Cabon, Nolwenn
AU - Robin-Le Guen, Françoise
AU - Ledoux-Rak, Isabelle
AU - Kahlal, Samia
AU - Saillard, Jean Yves
AU - Carrillo, David
AU - Hamon, Jean René
N1 - Funding Information:
The authors thank P. Hamon (ISCR, Rennes) and P. Jéhan (CRMPO, Rennes) for helpful assistance with NMR and HR-MS measurements, respectively. This research has been performed as part of the Chilean-French International Associated Laboratory for ‘‘Multifunctional Molecules and Materials‘‘ (LIA M3-CNRS No. 1207). Financial support from the Fondo Nacional de Desarrollo Científico y Tecnológico [FONDECYT (Chile), grant no. 1130105 (D. C. and C. M.)], the Vicerrectoría de Investigación y Estudios Avanzados, Pontificia Universidad Católica de Valparáıso, Chile (D. C. and C. M.), the CNRS and the Universitéde Rennes 1 are gratefully acknowledged. The GENCI French national computer center is acknowledged for computational resources (Grant a0050807367). N. C. gratefully thanks Dr N. Le Poul and UMR 6521 (Universitéde Bretagne Occidentale, Brest), for helpful discussion and their technical support in spectroelectrochemistry. N. N. thanks also the CONICYT (Chile) and BECAS-CHILE for support of a graduate and Joint Supervision Scholarship (PUCV/UR1).
Funding Information:
The authors thank P. Hamon (ISCR, Rennes) and P. Jéhan (CRMPO, Rennes) for helpful assistance with NMR and HR-MS measurements, respectively. This research has been performed as part of the Chilean-French International Associated Laboratory for "Multifunctional Molecules and Materials" (LIA M3-CNRS No. 1207). Financial support from the Fondo Nacional de Desarrollo Científico y Tecnológico [FONDECYT (Chile), grant no. 1130105 (D. C. and C. M.)], the Vicerrectoría de Investigación y Estudios Avanzados, Pontificia Universidad Católica de Valparaíso, Chile (D. C. and C. M.), the CNRS and the Université de Rennes 1 are gratefully acknowledged. The GENCI French national computer center is acknowledged for computational resources (Grant a0050807367). N. C. gratefully thanks Dr N. Le Poul and UMR 6521 (Université de Bretagne Occidentale, Brest), for helpful discussion and their technical support in spectroelectrochemistry. N. N. thanks also the CONICYT (Chile) and BECAS-CHILE for support of a graduate and Joint Supervision Scholarship (PUCV/UR1).
Publisher Copyright:
© 2019 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
PY - 2019
Y1 - 2019
N2 - Four new ternary Ni(ii) and Cu(ii) complexes of ONO tridentate Schiff base and pyridylmethylenepyran (PyMP) ligands [(R-ONO)M(PyMP)] (R = anisyl = An: M = Ni 1, Cu 2; R = ferrocenyl = Fc: M = Ni 3, Cu 4) have been synthesized under facile reaction conditions starting from R-ONOH2, metal(ii) nitrate salts, and PyMP; R-ONOH2 stands for the Schiff base ligand precursors obtained by condensation of either 1-anisyl- or 1-ferrocenyl-butan-1,3-dione and 2-aminophenol. They have been thoroughly characterized with the help of various physicochemical tools, such as CHN analyses, IR and UV-vis spectra, 1H NMR for diamagnetic Ni(ii) derivatives 1 and 3, and HRMS for paramagnetic Cu(ii) species 2 and 4. The molecular structures of 1-3 were authenticated by single-crystal X-ray diffraction methods, along with that of the doubly phenoxide-bridged dimer [Cu2(μ-ONO-Fc)2(PyMp)2] (4′), resulting from the recrystallization of 4. In 1-3, the four-coordinate nickel and copper atoms adopt a square planar geometry, whereas in 4′ the CuII metal ion is five-coordinated in a square pyramidal environment with the pyridyl nitrogen occupying the apex. Electrochemical studies reveal two well-separated redox waves. The spin density distribution analyses reveal that the initial oxidation process is associated with a ligand-based level, with some ferrocenyl participation for the heterobimetallic compounds 3 and 4. Reversible redox switching can be established for 1 and 3 by time-resolved spectroelectrochemistry under thin-layer conditions where electrochemical cycling is associated with a significant modification of the UV-vis spectra of the chromophores. The second-order nonlinear optical responses of 1-4 along with those of assumed bispyrylium dimeric species 5 and 6, generated by chemical oxidation of 1 and 3, respectively, have been determined by harmonic light scattering measurements in dichloromethane solutions at 1.91 μm incident wavelength. Rather high β values ranging from 270-530 × 10-30 esu were determined for 1-4. The β value of 5 (800 × 10-30 esu) was found to be almost twice that of its monomeric precursor 1, whereas the β value of 6 (160 × 10-30 esu) is reduced by half with respect to that of 3. In 5 the anisyl retains its donor ability whereas in 6 the electron-donating character of the oxidized ferrocenyl moiety is cancelled. Optimized geometries of the four compounds 1-4 as well as their electronic structures and that of their respective cations 1+-4+ have been analyzed through DFT calculations, while TD-DFT computation has been used to interpret the major features of the UV-vis spectra.
AB - Four new ternary Ni(ii) and Cu(ii) complexes of ONO tridentate Schiff base and pyridylmethylenepyran (PyMP) ligands [(R-ONO)M(PyMP)] (R = anisyl = An: M = Ni 1, Cu 2; R = ferrocenyl = Fc: M = Ni 3, Cu 4) have been synthesized under facile reaction conditions starting from R-ONOH2, metal(ii) nitrate salts, and PyMP; R-ONOH2 stands for the Schiff base ligand precursors obtained by condensation of either 1-anisyl- or 1-ferrocenyl-butan-1,3-dione and 2-aminophenol. They have been thoroughly characterized with the help of various physicochemical tools, such as CHN analyses, IR and UV-vis spectra, 1H NMR for diamagnetic Ni(ii) derivatives 1 and 3, and HRMS for paramagnetic Cu(ii) species 2 and 4. The molecular structures of 1-3 were authenticated by single-crystal X-ray diffraction methods, along with that of the doubly phenoxide-bridged dimer [Cu2(μ-ONO-Fc)2(PyMp)2] (4′), resulting from the recrystallization of 4. In 1-3, the four-coordinate nickel and copper atoms adopt a square planar geometry, whereas in 4′ the CuII metal ion is five-coordinated in a square pyramidal environment with the pyridyl nitrogen occupying the apex. Electrochemical studies reveal two well-separated redox waves. The spin density distribution analyses reveal that the initial oxidation process is associated with a ligand-based level, with some ferrocenyl participation for the heterobimetallic compounds 3 and 4. Reversible redox switching can be established for 1 and 3 by time-resolved spectroelectrochemistry under thin-layer conditions where electrochemical cycling is associated with a significant modification of the UV-vis spectra of the chromophores. The second-order nonlinear optical responses of 1-4 along with those of assumed bispyrylium dimeric species 5 and 6, generated by chemical oxidation of 1 and 3, respectively, have been determined by harmonic light scattering measurements in dichloromethane solutions at 1.91 μm incident wavelength. Rather high β values ranging from 270-530 × 10-30 esu were determined for 1-4. The β value of 5 (800 × 10-30 esu) was found to be almost twice that of its monomeric precursor 1, whereas the β value of 6 (160 × 10-30 esu) is reduced by half with respect to that of 3. In 5 the anisyl retains its donor ability whereas in 6 the electron-donating character of the oxidized ferrocenyl moiety is cancelled. Optimized geometries of the four compounds 1-4 as well as their electronic structures and that of their respective cations 1+-4+ have been analyzed through DFT calculations, while TD-DFT computation has been used to interpret the major features of the UV-vis spectra.
UR - http://www.scopus.com/inward/record.url?scp=85068358150&partnerID=8YFLogxK
U2 - 10.1039/c9nj01774g
DO - 10.1039/c9nj01774g
M3 - Article
AN - SCOPUS:85068358150
VL - 43
SP - 10468
EP - 10481
JO - New Journal of Chemistry
JF - New Journal of Chemistry
SN - 1144-0546
IS - 26
ER -