%0 Journal Article %1 Manzur.2007 %A Manzur, Jorge %A Vega, Andres %A Garcia, Ana Maria %A Acuna, Carolina %A Sieger, Monika %A Sarkar, Biprajit %A Niemeyer, Mark %A Lissner, Falk %A Schleid, Thomas %A Kaim, Wolfgang. %D 2007 %J European Journal of Inorganic Chemistry %K anion anion;prepn anion;structure bispyridinylalkylbenzylamine bridging complex copper crystal dinuclear prediction structure %N 35 %P 5500--5510 %R 10.1002/ejic.200700637 %T Coordination alternatives in dinuclear bis(pyridin-2-ylalkyl)benzylamine copper(II) complexes with OH-, RO-, F-, or Cl- bridges: Experimental structures and DFT preferences %X [L1Cu(m-OH)2CuL1](ClO4)2 (1), [L2Cu(m-OH)2CuL2](ClO4)2 (2), [L3Cu(m-OH)2CuL3](ClO4)2 (3), [L3Cu(m-OMe)2CuL3](ClO4)2 (4), [L3Cu(m-F)2CuL3](BF4)2 (5), [L4Cu(m-Cl)2CuL4](ClO4)2 (6), and [Cu(m-L5)2Cu](ClO4)2 (7), where L1 = bis(pyridin-2-ylmethyl)benzylamine, L2 = (6-methylpyridin-2-ylmethyl)(pyridin-2-ylmethyl)benzylamine, L3 = bis(6-methylpyridin-2-ylmethyl)benzylamine, L4 = (pyridin-2-ylethyl)(pyridin-2-ylmethyl)benzylamine, and L5 = (6-oxidomethylpyridin-2-ylmethyl)(6-methylpyridin-2-ylmethyl)benzylamine, were prepd., structurally characterized and studied by low-temp. EPR spectroscopy. The formation of compd. 5 involved fluoride abstraction from BF4- and that of 7 involved O2-assisted C-H (methyl) activation/monooxygenation of L3. Whereas the dications of 1-4 and 7 possess a square-pyramidal configuration at the copper(II) centers with hydroxide or alkoxide bridges in equatorial positions, the dications of 5 and 6 exhibit equatorial/axial arrangements for the bridging halide ions. In the dication of 5, the tridentate ligand binds in a meridional fashion and includes two adjacent five-membered chelate rings. Such a situation was obsd. previously only with chloride, alkoxide, or aqua bridges. In contrast to the syn configuration of the dication of 2, the dications of complexes 1, 3, 4, and 7 adopt an anti configuration with respect to the binding of Ln. The dications of 1, 2, and 7 have the pyridinyl or 6-methylpyridinyl groups in the axial position, whereas those of 3 and 4 feature the tertiary amine N atom at that site. DFT calcns. of various configurations of the dications of 1-6 reproduce the exptl. obsd. structural alternatives in complexes 1-4, but they do not predict the axial/equatorial structure of 5 as the lowest-energy configuration. The systematic overestimation of repulsive forces and thus of distances by DFT may result in an underestimation of the p-p interaction between the largely coplanar mer-L3 ligands sepd. by $\sim$3.6 \AA in 5, which probably affects its structure. By incorporating these and previous results, the syn vs. anti, equatorial/equatorial vs. equatorial/axial, and axial pyridine vs. axial amine structural alternatives are discussed. [on SciFinder(R)]

@article{Manzur.2007, abstract = {[L1Cu(\textgreek{m}-OH)2CuL1](ClO4)2 (1), [L2Cu(\textgreek{m}-OH)2CuL2](ClO4)2 (2), [L3Cu(\textgreek{m}-OH)2CuL3](ClO4)2 (3), [L3Cu(\textgreek{m}-OMe)2CuL3](ClO4)2 (4), [L3Cu(\textgreek{m}-F)2CuL3](BF4)2 (5), [L4Cu(\textgreek{m}-Cl)2CuL4](ClO4)2 (6), and [Cu(\textgreek{m}-L5)2Cu](ClO4)2 (7), where L1 = bis(pyridin-2-ylmethyl)benzylamine, L2 = (6-methylpyridin-2-ylmethyl)(pyridin-2-ylmethyl)benzylamine, L3 = bis(6-methylpyridin-2-ylmethyl)benzylamine, L4 = (pyridin-2-ylethyl)(pyridin-2-ylmethyl)benzylamine, and L5 = (6-oxidomethylpyridin-2-ylmethyl)(6-methylpyridin-2-ylmethyl)benzylamine, were prepd., structurally characterized and studied by low-temp. EPR spectroscopy. The formation of compd. 5 involved fluoride abstraction from BF4- and that of 7 involved O2-assisted C-H (methyl) activation/monooxygenation of L3. Whereas the dications of 1-4 and 7 possess a square-pyramidal configuration at the copper(II) centers with hydroxide or alkoxide bridges in equatorial positions, the dications of 5 and 6 exhibit equatorial/axial arrangements for the bridging halide ions. In the dication of 5, the tridentate ligand binds in a meridional fashion and includes two adjacent five-membered chelate rings. Such a situation was obsd. previously only with chloride, alkoxide, or aqua bridges. In contrast to the syn configuration of the dication of 2, the dications of complexes 1, 3, 4, and 7 adopt an anti configuration with respect to the binding of Ln. The dications of 1, 2, and 7 have the pyridinyl or 6-methylpyridinyl groups in the axial position, whereas those of 3 and 4 feature the tertiary amine N atom at that site. DFT calcns. of various configurations of the dications of 1-6 reproduce the exptl. obsd. structural alternatives in complexes 1-4, but they do not predict the axial/equatorial structure of 5 as the lowest-energy configuration. The systematic overestimation of repulsive forces and thus of distances by DFT may result in an underestimation of the \textgreek{p}-\textgreek{p} interaction between the largely coplanar mer-L3 ligands sepd. by $\sim$3.6 {\AA} in 5, which probably affects its structure. By incorporating these and previous results, the syn vs. anti, equatorial/equatorial vs. equatorial/axial, and axial pyridine vs. axial amine structural alternatives are discussed. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Manzur, Jorge and Vega, Andres and Garcia, Ana Maria and Acuna, Carolina and Sieger, Monika and Sarkar, Biprajit and Niemeyer, Mark and Lissner, Falk and Schleid, Thomas and Kaim, Wolfgang.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/216816855aac27a3d46670945815865c6/huebleriac}, doi = {10.1002/ejic.200700637}, interhash = {fa4b303565cb216df7c7a3930d1ca35d}, intrahash = {16816855aac27a3d46670945815865c6}, issn = {1434-1948}, journal = {European Journal of Inorganic Chemistry}, keywords = {anion anion;prepn anion;structure bispyridinylalkylbenzylamine bridging complex copper crystal dinuclear prediction structure}, number = 35, pages = {5500--5510}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Coordination alternatives in dinuclear bis(pyridin-2-ylalkyl)benzylamine copper(II) complexes with OH-, RO-, F-, or Cl- bridges: Experimental structures and DFT preferences}, year = 2007 }