Linked Life Data

15819581

Source:http://linkedlifedata.com/resource/pubmed/id/15819581

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2005-4-11
pubmed:abstractText
A new family of relatively stable Cr(V) complexes, [Cr(V)O(L)(2)](-) (LH(2) = RC(O)NHOH, R = Me, Ph, 2-HO-Ph, or HONHC(O)(CH(2))(6)), has been obtained by the reactions of hydroxamic acids with Cr(VI) in polar aprotic solvents. Similar reactions in aqueous solutions led to the formation of transient Cr(V) species. All complexes have been characterized by electron paramagnetic resonance spectroscopy and electrospray mass spectrometry. A Cr(V) complex of benzohydroxamic acid (1, R = Ph) was isolated in a pure form (as a K(+) salt) and was characterized by X-ray absorption spectroscopy and analytical techniques. Multiple-scattering analysis of X-ray absorption fine structure spectroscopic data for 1 (solid, 10 K) point to a distorted trigonal-bipyramidal structure with trans-oriented Ph groups and Cr-ligand bond lengths of 1.58 A (Cr-O), 1.88 A (Cr-O(C)), and 1.98 A (Cr-O(N)). Under ambient conditions, 1 is stable for days in aprotic solvents but decomposes within minutes in aqueous solutions (maximal stability at pH approximately 7), which leads predominantly to the formation of Cr(III) complexes. Complex 1 readily undergoes ligand-exchange reactions with biological 1,2-diols, including D-glucose and mucin, in neutral aqueous solutions. It differs from most other types of Cr(V) complexes in its biological activity, since no oxidative cleavage of plasmid DNA in vitro and no significant bacterial mutagenicity (in the TA 102 strain of Salmonella typhimurium) was observed for 1. In natural systems, stabilization of Cr(V) by hydroxamato ligands from bacterial-derived siderophores (followed by ligand-exchange reactions with more abundant carbohydrate ligands) may occur during the biological reduction of Cr(VI) in contaminated soils.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0020-1669
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
44
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2934-43
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Chromium(V) complexes of hydroxamic acids: formation, structures, and reactivities.
pubmed:affiliation
Centre for Heavy Metals Research, School of Chemistry, University of Sydney, NSW, 2006, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't