Source:http://linkedlifedata.com/resource/pubmed/id/17173457
Switch to
| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
26
|
| pubmed:dateCreated |
2006-12-18
|
| pubmed:abstractText |
This paper presents some copper(II) complexes of salen analogues in which the two salicylaldehyde moieties carry different (electron donor, D, and acceptor, A) substituents in position 5, producing a push-pull charge asymmetry. The X-ray structures of some compounds show the presence of pairs of stacked molecules with head-to-tail intermolecular associations. The geometries of all complexes have been optimized through density functional theory (DFT) studies, which have shown that a major influence on the coordination bond lengths is given by the presence of the electron acceptor NO2 group. Such an influence operates mainly on the Cu-phenolato bonds: elongation of the Cu-O distance of the 5-nitrosalicylaldehyde moiety, with a concomitant decrease of the other Cu-O distance; the Cu-N bonds are less affected. The D groups have only a minor influence. The nonlinear optical responses, microgBetavec, of some molecules have been determined by EFISH measurements, and the Beta-vec values have been obtained using the DFT-calculated microg values because solubility problems hampered the experimental measurements of microg of some derivatives; the former, however, have been found to be in agreement with the experimental values that could be obtained. Deconvolution of the absorption bands in the near-UV region has allowed recognition of the charge-transfer (CT) transition, assigned to a ligand-to-metal CT (LMCT) by time-dependent DFT computations; we have then used the solvatochromism of this transition to obtain Beta0 and BetaCT values using the two-state model. These values were compared with those obtained by computational studies, which have also allowed evaluation of the influence of the substituents on the directions of microg and Betatot.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:status |
PubMed-not-MEDLINE
|
| pubmed:month |
Dec
|
| pubmed:issn |
0020-1669
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
25
|
| pubmed:volume |
45
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
10976-89
|
| pubmed:year |
2006
|
| pubmed:articleTitle |
Copper(II) complexes of salen analogues with two differently substituted (push-pull) salicylaldehyde moieties. A study on the modulation of electronic asymmetry and nonlinear optical properties.
|
| pubmed:affiliation |
Dipartimento di Chimica Inorganica, Metallorganica e Analitica, and Dipartimento di Chimica Strutturale e Stereochimica Inorganica, Università degli Studi di Milano, via G. Venezian 21, 20133 Milan, Italy.
|
| pubmed:publicationType |
Journal Article
|