Coordination alternatives in dinuclear bis(pyridin-2-ylalkyl)- benzylaminecopper(II) complexes with OH-, RO-, F -, or Cl- bridges: Experimental structures and DFT preferences

Jorge Manzur, Andrés Vega, Ana María García, Carolina Acuña, Monika Sieger, Biprajit Sarkar, Mark Niemeyer, Falk Lissner, Thomas Schleid, Wolfgang Kaim

Resultado de la investigación: Article

19 Citas (Scopus)

Resumen

The compounds [L1Cu(μ-OH)2CuL1] (ClO4)2 (1), [L2Cu(μ-OH)2CuL 2](ClO4)2 (2), [L3Cu(μ-OH) 2CuL3](ClO4)2 (3), [L 3Cu-(μ-OMe)2CuL3](ClO4) 2 (4), [L3Cu(μ-F)2CuL3](BF 4)2 (5), [L4Cu-(μ-Cl)2CuL 4](ClO4)2 (6), and [Cu(μ-L5) 2Cu](ClO4)2 (7), where L1 = bis(pyridin-2-ylmethyl)benzylamine, L2 = (6-methyl-pyridin-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-yl-methyl)benzylamine, were structurally characterized and studied by low-temperature EPR spectroscopy. The formation of compound 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 has been observed 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-methyl-pyridinyl groups in the axial position, whereas those of 3 and 4 feature the tertiary amine N atom at that site. DFT calculations of various configurations of the dications of 1-6 reproduce the experimentally observed 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 π-π interaction between the largely coplanar mer-L3 ligands separated by about 3.6 Å in 5, which probably affects its structure. By incorporating these and previous results, the syn versus anti, equatorial/equatorial versus equatorial/axial, and axial pyridine versus axial amine structural alternatives are discussed.

Idioma originalEnglish
Páginas (desde-hasta)5500-5510
Número de páginas11
PublicaciónEuropean Journal of Inorganic Chemistry
N.º35
DOI
EstadoPublished - 2007

Huella dactilar

Discrete Fourier transforms
Amines
Ligands
Fluorides
Paramagnetic resonance
hydroxide ion
perchlorate
Chlorides
Copper
Chemical activation
benzylamine
Spectroscopy
Ions
Atoms
Temperature

ASJC Scopus subject areas

  • Inorganic Chemistry

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Manzur, Jorge ; Vega, Andrés ; García, Ana María ; Acuña, Carolina ; Sieger, Monika ; Sarkar, Biprajit ; Niemeyer, Mark ; Lissner, Falk ; Schleid, Thomas ; Kaim, Wolfgang. / Coordination alternatives in dinuclear bis(pyridin-2-ylalkyl)- benzylaminecopper(II) complexes with OH-, RO-, F -, or Cl- bridges : Experimental structures and DFT preferences. En: European Journal of Inorganic Chemistry. 2007 ; N.º 35. pp. 5500-5510.
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title = "Coordination alternatives in dinuclear bis(pyridin-2-ylalkyl)- benzylaminecopper(II) complexes with OH-, RO-, F -, or Cl- bridges: Experimental structures and DFT preferences",
abstract = "The compounds [L1Cu(μ-OH)2CuL1] (ClO4)2 (1), [L2Cu(μ-OH)2CuL 2](ClO4)2 (2), [L3Cu(μ-OH) 2CuL3](ClO4)2 (3), [L 3Cu-(μ-OMe)2CuL3](ClO4) 2 (4), [L3Cu(μ-F)2CuL3](BF 4)2 (5), [L4Cu-(μ-Cl)2CuL 4](ClO4)2 (6), and [Cu(μ-L5) 2Cu](ClO4)2 (7), where L1 = bis(pyridin-2-ylmethyl)benzylamine, L2 = (6-methyl-pyridin-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-yl-methyl)benzylamine, were structurally characterized and studied by low-temperature EPR spectroscopy. The formation of compound 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 has been observed 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-methyl-pyridinyl groups in the axial position, whereas those of 3 and 4 feature the tertiary amine N atom at that site. DFT calculations of various configurations of the dications of 1-6 reproduce the experimentally observed 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 π-π interaction between the largely coplanar mer-L3 ligands separated by about 3.6 {\AA} in 5, which probably affects its structure. By incorporating these and previous results, the syn versus anti, equatorial/equatorial versus equatorial/axial, and axial pyridine versus axial amine structural alternatives are discussed.",
keywords = "Copper, EPR spectroscopy, Isomerism, N ligands, Structure",
author = "Jorge Manzur and Andr{\'e}s Vega and Garc{\'i}a, {Ana Mar{\'i}a} and Carolina Acu{\~n}a and Monika Sieger and Biprajit Sarkar and Mark Niemeyer and Falk Lissner and Thomas Schleid and Wolfgang Kaim",
year = "2007",
doi = "10.1002/ejic.200700637",
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Coordination alternatives in dinuclear bis(pyridin-2-ylalkyl)- benzylaminecopper(II) complexes with OH-, RO-, F -, or Cl- bridges : Experimental structures and DFT preferences. / Manzur, Jorge; Vega, Andrés; García, Ana María; Acuña, Carolina; Sieger, Monika; Sarkar, Biprajit; Niemeyer, Mark; Lissner, Falk; Schleid, Thomas; Kaim, Wolfgang.

En: European Journal of Inorganic Chemistry, N.º 35, 2007, p. 5500-5510.

Resultado de la investigación: Article

TY - JOUR

T1 - Coordination alternatives in dinuclear bis(pyridin-2-ylalkyl)- benzylaminecopper(II) complexes with OH-, RO-, F -, or Cl- bridges

T2 - Experimental structures and DFT preferences

AU - Manzur, Jorge

AU - Vega, Andrés

AU - García, Ana María

AU - Acuña, Carolina

AU - Sieger, Monika

AU - Sarkar, Biprajit

AU - Niemeyer, Mark

AU - Lissner, Falk

AU - Schleid, Thomas

AU - Kaim, Wolfgang

PY - 2007

Y1 - 2007

N2 - The compounds [L1Cu(μ-OH)2CuL1] (ClO4)2 (1), [L2Cu(μ-OH)2CuL 2](ClO4)2 (2), [L3Cu(μ-OH) 2CuL3](ClO4)2 (3), [L 3Cu-(μ-OMe)2CuL3](ClO4) 2 (4), [L3Cu(μ-F)2CuL3](BF 4)2 (5), [L4Cu-(μ-Cl)2CuL 4](ClO4)2 (6), and [Cu(μ-L5) 2Cu](ClO4)2 (7), where L1 = bis(pyridin-2-ylmethyl)benzylamine, L2 = (6-methyl-pyridin-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-yl-methyl)benzylamine, were structurally characterized and studied by low-temperature EPR spectroscopy. The formation of compound 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 has been observed 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-methyl-pyridinyl groups in the axial position, whereas those of 3 and 4 feature the tertiary amine N atom at that site. DFT calculations of various configurations of the dications of 1-6 reproduce the experimentally observed 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 π-π interaction between the largely coplanar mer-L3 ligands separated by about 3.6 Å in 5, which probably affects its structure. By incorporating these and previous results, the syn versus anti, equatorial/equatorial versus equatorial/axial, and axial pyridine versus axial amine structural alternatives are discussed.

AB - The compounds [L1Cu(μ-OH)2CuL1] (ClO4)2 (1), [L2Cu(μ-OH)2CuL 2](ClO4)2 (2), [L3Cu(μ-OH) 2CuL3](ClO4)2 (3), [L 3Cu-(μ-OMe)2CuL3](ClO4) 2 (4), [L3Cu(μ-F)2CuL3](BF 4)2 (5), [L4Cu-(μ-Cl)2CuL 4](ClO4)2 (6), and [Cu(μ-L5) 2Cu](ClO4)2 (7), where L1 = bis(pyridin-2-ylmethyl)benzylamine, L2 = (6-methyl-pyridin-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-yl-methyl)benzylamine, were structurally characterized and studied by low-temperature EPR spectroscopy. The formation of compound 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 has been observed 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-methyl-pyridinyl groups in the axial position, whereas those of 3 and 4 feature the tertiary amine N atom at that site. DFT calculations of various configurations of the dications of 1-6 reproduce the experimentally observed 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 π-π interaction between the largely coplanar mer-L3 ligands separated by about 3.6 Å in 5, which probably affects its structure. By incorporating these and previous results, the syn versus anti, equatorial/equatorial versus equatorial/axial, and axial pyridine versus axial amine structural alternatives are discussed.

KW - Copper

KW - EPR spectroscopy

KW - Isomerism

KW - N ligands

KW - Structure

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U2 - 10.1002/ejic.200700637

DO - 10.1002/ejic.200700637

M3 - Article

AN - SCOPUS:37349108133

SP - 5500

EP - 5510

JO - Chemische Berichte

JF - Chemische Berichte

SN - 0009-2940

IS - 35

ER -