Syntheses, crystal structures and electronic properties of a series of copper(II) complexes with 3,5-halogen-substituted Schiff base ligands and their solutions

Takashiro Akitsu, Yasuaki Einaga

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58 Citations (Scopus)

Abstract

We have systematically investigated the structural features, electronic properties, thermally-induced structural phase transitions and absorption spectra depending on the solvent for ten Cu(II) complexes with 3,5-halogen-substituted Schiff base ligands. Structural characterization of two new complexes, bis(N-R-1-phenylethyl- and N-R,S-2-butyl-5-bromosalicydenaminato- κ2N,O)copper(II), reveals that they afford a compressed tetrahedral trans-[CuN2O2] coordination geometry with trans-N-Cu-N = 159.4(2)° and trans-O-Cu-O = 151.7(3)° for the 1-phenylethyl complex and trans-N-Cu-N = 157.9(3)° and trans-O-Cu-O = 151.0(3)° for the 2-butyl one. All the complexes exhibit a structural phase transition by heating in the solid state regardless of their structures at room temperature. The absorption spectra of a series of ten complexes exhibit a slight shift of the d-d band at 16 000-20 000 cm-1 and remarkable shift of the π-π* band at 24 000-28 000 cm-1, which suggests that the dipole moment of the solvents presumably affects the conformation of the π-conjugated moieties of the ligands rather than the coordination environment. We have also attempted 'photochromic solute-induced solvatochromism' by a system of bis(N-R-1-phenylethyl-3,5- dichlorosalicydenaminato-κ2N,O)copper(II) and photochromic 4-hydroxyazobenzene in chloroform solution. We successfully observed a change of the d-d and π-π* bands of the complex in the absorption spectra caused by cis-trans photoisomerization of 4-hydroxyazobenzene.

Original languageEnglish
Pages (from-to)2933-2943
Number of pages11
JournalPolyhedron
Volume24
Issue number18
DOIs
Publication statusPublished - 2005 Dec 8

Fingerprint

Halogens
Schiff Bases
Electronic properties
halogens
imines
Copper
Absorption spectra
Crystal structure
Phase Transition
Ligands
absorption spectra
copper
ligands
crystal structure
synthesis
Phase transitions
electronics
Photoisomerization
shift
Dipole moment

Keywords

  • Azobenzenes
  • Chirality
  • Copper(II) complexes
  • Crystal structures
  • Schiff base
  • Solvatochromism

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry
  • Physical and Theoretical Chemistry
  • Materials Chemistry

Cite this

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title = "Syntheses, crystal structures and electronic properties of a series of copper(II) complexes with 3,5-halogen-substituted Schiff base ligands and their solutions",
abstract = "We have systematically investigated the structural features, electronic properties, thermally-induced structural phase transitions and absorption spectra depending on the solvent for ten Cu(II) complexes with 3,5-halogen-substituted Schiff base ligands. Structural characterization of two new complexes, bis(N-R-1-phenylethyl- and N-R,S-2-butyl-5-bromosalicydenaminato- κ2N,O)copper(II), reveals that they afford a compressed tetrahedral trans-[CuN2O2] coordination geometry with trans-N-Cu-N = 159.4(2)° and trans-O-Cu-O = 151.7(3)° for the 1-phenylethyl complex and trans-N-Cu-N = 157.9(3)° and trans-O-Cu-O = 151.0(3)° for the 2-butyl one. All the complexes exhibit a structural phase transition by heating in the solid state regardless of their structures at room temperature. The absorption spectra of a series of ten complexes exhibit a slight shift of the d-d band at 16 000-20 000 cm-1 and remarkable shift of the π-π* band at 24 000-28 000 cm-1, which suggests that the dipole moment of the solvents presumably affects the conformation of the π-conjugated moieties of the ligands rather than the coordination environment. We have also attempted 'photochromic solute-induced solvatochromism' by a system of bis(N-R-1-phenylethyl-3,5- dichlorosalicydenaminato-κ2N,O)copper(II) and photochromic 4-hydroxyazobenzene in chloroform solution. We successfully observed a change of the d-d and π-π* bands of the complex in the absorption spectra caused by cis-trans photoisomerization of 4-hydroxyazobenzene.",
keywords = "Azobenzenes, Chirality, Copper(II) complexes, Crystal structures, Schiff base, Solvatochromism",
author = "Takashiro Akitsu and Yasuaki Einaga",
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language = "English",
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T1 - Syntheses, crystal structures and electronic properties of a series of copper(II) complexes with 3,5-halogen-substituted Schiff base ligands and their solutions

AU - Akitsu, Takashiro

AU - Einaga, Yasuaki

PY - 2005/12/8

Y1 - 2005/12/8

N2 - We have systematically investigated the structural features, electronic properties, thermally-induced structural phase transitions and absorption spectra depending on the solvent for ten Cu(II) complexes with 3,5-halogen-substituted Schiff base ligands. Structural characterization of two new complexes, bis(N-R-1-phenylethyl- and N-R,S-2-butyl-5-bromosalicydenaminato- κ2N,O)copper(II), reveals that they afford a compressed tetrahedral trans-[CuN2O2] coordination geometry with trans-N-Cu-N = 159.4(2)° and trans-O-Cu-O = 151.7(3)° for the 1-phenylethyl complex and trans-N-Cu-N = 157.9(3)° and trans-O-Cu-O = 151.0(3)° for the 2-butyl one. All the complexes exhibit a structural phase transition by heating in the solid state regardless of their structures at room temperature. The absorption spectra of a series of ten complexes exhibit a slight shift of the d-d band at 16 000-20 000 cm-1 and remarkable shift of the π-π* band at 24 000-28 000 cm-1, which suggests that the dipole moment of the solvents presumably affects the conformation of the π-conjugated moieties of the ligands rather than the coordination environment. We have also attempted 'photochromic solute-induced solvatochromism' by a system of bis(N-R-1-phenylethyl-3,5- dichlorosalicydenaminato-κ2N,O)copper(II) and photochromic 4-hydroxyazobenzene in chloroform solution. We successfully observed a change of the d-d and π-π* bands of the complex in the absorption spectra caused by cis-trans photoisomerization of 4-hydroxyazobenzene.

AB - We have systematically investigated the structural features, electronic properties, thermally-induced structural phase transitions and absorption spectra depending on the solvent for ten Cu(II) complexes with 3,5-halogen-substituted Schiff base ligands. Structural characterization of two new complexes, bis(N-R-1-phenylethyl- and N-R,S-2-butyl-5-bromosalicydenaminato- κ2N,O)copper(II), reveals that they afford a compressed tetrahedral trans-[CuN2O2] coordination geometry with trans-N-Cu-N = 159.4(2)° and trans-O-Cu-O = 151.7(3)° for the 1-phenylethyl complex and trans-N-Cu-N = 157.9(3)° and trans-O-Cu-O = 151.0(3)° for the 2-butyl one. All the complexes exhibit a structural phase transition by heating in the solid state regardless of their structures at room temperature. The absorption spectra of a series of ten complexes exhibit a slight shift of the d-d band at 16 000-20 000 cm-1 and remarkable shift of the π-π* band at 24 000-28 000 cm-1, which suggests that the dipole moment of the solvents presumably affects the conformation of the π-conjugated moieties of the ligands rather than the coordination environment. We have also attempted 'photochromic solute-induced solvatochromism' by a system of bis(N-R-1-phenylethyl-3,5- dichlorosalicydenaminato-κ2N,O)copper(II) and photochromic 4-hydroxyazobenzene in chloroform solution. We successfully observed a change of the d-d and π-π* bands of the complex in the absorption spectra caused by cis-trans photoisomerization of 4-hydroxyazobenzene.

KW - Azobenzenes

KW - Chirality

KW - Copper(II) complexes

KW - Crystal structures

KW - Schiff base

KW - Solvatochromism

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