Abstract
Two new mononuclear nickel (II) complexes incorporating Schiff base ligands, bis(N-R-1-phenylethyl- or N-2-propyl-3,5-dichlorosalicydenaminato) nickel (II), have been synthesized and characterized. The former chiral brown paramagnetic complex adopts a compressed tetrahedral [NiN2O 2] coordination geometry of Λ(R,R) absolute configuration with the coordination bond angles of N-Ni-N = 116.3(2)°and O-Ni-O = 141.4(2)°. On the other hand, the latter green diamagnetic complex adopts a square planar trans-[NiN2O2] coordination geometry. It is revealed that flexible distortion of the [NiN2O2] coordination environment and the overall dipole moment of the complexes are affected by both electronic withdrawing Cl-substituents and steric factors of the ligands. A structural phase transition occurs by heating in the solid state for both complexes. Negative solvatochromism relating to d-d and π-π* transitions can be observed, depending on the polarity of the solvents in which these complexes are dissolved. Furthermore, we have attempted to design a supramolecular solvatochromism system induced by a photochromic solute, that is a CHCl3 solution of the chiral Ni(II) complex and polar 4-hydroxyazobenzene solute. After UV light irradiation, we have successfully observed slight spectral changes of the π-π* bands in absorption and CD spectra due to conformational change of the R-1-phenylethylamine moieties of the chiral ligands.
| Original language | English |
|---|---|
| Pages (from-to) | 1869-1877 |
| Number of pages | 9 |
| Journal | Polyhedron |
| Volume | 24 |
| Issue number | 14 |
| DOIs | |
| Publication status | Published - 2005 Oct 3 |
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Keywords
- Chirality
- Crystal structures
- Nickel (II) complexes
- Schiff base
- Solvatochromism
ASJC Scopus subject areas
- Biochemistry
- Inorganic Chemistry
- Physical and Theoretical Chemistry
- Materials Chemistry
Cite this
Synthesis, crystal structures and electronic properties of Schiff base nickel (II) complexes : Towards solvatochromism induced by a photochromic solute. / Akitsu, Takashiro; Einaga, Yasuaki.
In: Polyhedron, Vol. 24, No. 14, 03.10.2005, p. 1869-1877.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Synthesis, crystal structures and electronic properties of Schiff base nickel (II) complexes
T2 - Towards solvatochromism induced by a photochromic solute
AU - Akitsu, Takashiro
AU - Einaga, Yasuaki
PY - 2005/10/3
Y1 - 2005/10/3
N2 - Two new mononuclear nickel (II) complexes incorporating Schiff base ligands, bis(N-R-1-phenylethyl- or N-2-propyl-3,5-dichlorosalicydenaminato) nickel (II), have been synthesized and characterized. The former chiral brown paramagnetic complex adopts a compressed tetrahedral [NiN2O 2] coordination geometry of Λ(R,R) absolute configuration with the coordination bond angles of N-Ni-N = 116.3(2)°and O-Ni-O = 141.4(2)°. On the other hand, the latter green diamagnetic complex adopts a square planar trans-[NiN2O2] coordination geometry. It is revealed that flexible distortion of the [NiN2O2] coordination environment and the overall dipole moment of the complexes are affected by both electronic withdrawing Cl-substituents and steric factors of the ligands. A structural phase transition occurs by heating in the solid state for both complexes. Negative solvatochromism relating to d-d and π-π* transitions can be observed, depending on the polarity of the solvents in which these complexes are dissolved. Furthermore, we have attempted to design a supramolecular solvatochromism system induced by a photochromic solute, that is a CHCl3 solution of the chiral Ni(II) complex and polar 4-hydroxyazobenzene solute. After UV light irradiation, we have successfully observed slight spectral changes of the π-π* bands in absorption and CD spectra due to conformational change of the R-1-phenylethylamine moieties of the chiral ligands.
AB - Two new mononuclear nickel (II) complexes incorporating Schiff base ligands, bis(N-R-1-phenylethyl- or N-2-propyl-3,5-dichlorosalicydenaminato) nickel (II), have been synthesized and characterized. The former chiral brown paramagnetic complex adopts a compressed tetrahedral [NiN2O 2] coordination geometry of Λ(R,R) absolute configuration with the coordination bond angles of N-Ni-N = 116.3(2)°and O-Ni-O = 141.4(2)°. On the other hand, the latter green diamagnetic complex adopts a square planar trans-[NiN2O2] coordination geometry. It is revealed that flexible distortion of the [NiN2O2] coordination environment and the overall dipole moment of the complexes are affected by both electronic withdrawing Cl-substituents and steric factors of the ligands. A structural phase transition occurs by heating in the solid state for both complexes. Negative solvatochromism relating to d-d and π-π* transitions can be observed, depending on the polarity of the solvents in which these complexes are dissolved. Furthermore, we have attempted to design a supramolecular solvatochromism system induced by a photochromic solute, that is a CHCl3 solution of the chiral Ni(II) complex and polar 4-hydroxyazobenzene solute. After UV light irradiation, we have successfully observed slight spectral changes of the π-π* bands in absorption and CD spectra due to conformational change of the R-1-phenylethylamine moieties of the chiral ligands.
KW - Chirality
KW - Crystal structures
KW - Nickel (II) complexes
KW - Schiff base
KW - Solvatochromism
UR - http://www.scopus.com/inward/record.url?scp=24644442850&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=24644442850&partnerID=8YFLogxK
U2 - 10.1016/j.poly.2005.06.019
DO - 10.1016/j.poly.2005.06.019
M3 - Article
AN - SCOPUS:24644442850
VL - 24
SP - 1869
EP - 1877
JO - Polyhedron
JF - Polyhedron
SN - 0277-5387
IS - 14
ER -