Linked Life Data

19705918

Source:http://linkedlifedata.com/resource/pubmed/id/19705918

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
34
pubmed:dateCreated
2009-8-26
pubmed:abstractText
A series of Mn(IV)(salen)(L)(2) complexes bearing different external axial ligands (L = Cl, NO(3), N(3), and OCH(2)CF(3)) from chiral salen ligands with trans-cyclohexane-1,2-diamine as a chiral scaffold are synthesized, to gain insight into conformational properties of metal salen complexes. X-ray crystal structures show that Mn(IV)(salen)(OCH(2)CF(3))(2) and Mn(IV)(salen)(N(3))(2) adopt a stepped conformation with one of two salicylidene rings pointing upward and the other pointing downward due to the bias from the trans-cyclohexane-1,2-diamine moiety, which is in clear contrast to a relatively planar solid-state conformation for Mn(IV)(salen)(Cl)(2). The CH(2)Cl(2) solution of Mn(IV)(salen)(L)(2) shows circular dichroism of increasing intensity in the order L = Cl < NO(3) << N(3) < OCH(2)CF(3), which indicates Mn(IV)(salen)(L)(2) adopts a solution conformation of an increasing chiral distortion in this order. Quantum-chemical calculations with a symmetry adapted cluster-configuration interaction method indicate that a stepped conformation exhibits more intense circular dichroism than a planar conformation. The present study clarifies an unexpected new finding that the external axial ligands (L) play a critical role in amplifying the chirality in trans-cyclohexane-1,2-diamine in Mn(IV)(salen)(L)(2) to facilitate the formation of a chirally distorted conformation, possibly a stepped conformation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1520-5126
pubmed:author
pubmed:issnType
Electronic
pubmed:day
2
pubmed:volume
131
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12394-405
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Critical role of external axial ligands in chirality amplification of trans-cyclohexane-1,2-diamine in salen complexes.
pubmed:affiliation
Institute for Molecular Science, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8787, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't