Multifunctional mononuclear bisthienylethene-cobalt(II) complexes: structures, slow magnetic relaxation and photochromic behavior.
Dalton Trans
; 44(12): 5755-62, 2015 Mar 28.
Article
em En
| MEDLINE
| ID: mdl-25714230
ABSTRACT
Based on two new bisthienylethenes containing N,O-donor binding sites, 2-(2-hydroxy-5-bromo-phenyl)-4,5-bis(2,5-dimethyl(3-thienyl))-1H-imidazole (BrLH) and 2-(2-hydroxy-5-diethylphosphono-phenyl)-4,5-bis(2,5-dimethyl(3-thienyl))-1H-imidazole (PLH), multifunctional mononuclear complexes Co(BrL)2·3CH3OH (1) and Co(PL)2·2CH3OH (2) have been synthesized and characterized by crystallographic analysis. In the molecular structures of 1 and 2, the Co(II) ion adopts a distorted tetrahedral coordination geometry, and is coordinated by two nonequivalent bisthienylethene molecules (BrL− in 1, PL− in 2), showing non-photoactive parallel and photoactive antiparallel conformations, respectively. Compounds 1 and 2 show a distinct distortion of Co(II) coordination geometry, with bond angles of NCoN = 112.71(12)° and OCoO = 99.87(11)° for 1 and NCoN = 119.93(12)° and OCoO = 107.31(13)° for 2. Thus, 1 and 2 revealed different magnetic behaviors, which are demonstrated by the χMT vs. T plots, and the frequency dependence of the χ'M and χ''M signals at low temperature. Besides the field-induced slow magnetic relaxation, both 1 and 2 also showed photochromic behavior. Upon irradiation with 360 nm light for 1 and 343 nm light for 2, their CH2Cl2CH3CN solutions could change color from being nearly colorless to blue purple. It was demonstrated that the substituent groups of Br atom and PO(OEt)2 in 1 and 2, respectively, could significantly influence their crystal structures, magnetic relaxations and photochromic properties.
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Bases de dados:
MEDLINE
Idioma:
En
Revista:
Dalton Trans
Assunto da revista:
QUIMICA
Ano de publicação:
2015
Tipo de documento:
Article