Linked Life Data

20023874

Source:http://linkedlifedata.com/resource/pubmed/id/20023874

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
47
pubmed:dateCreated
2009-12-23
pubmed:abstractText
This paper reports the synthesis, crystal structures, and magnetic properties of a series of mixed-valence polynuclear manganese complexes bridged by a dianionic 1,2,4-triazole-based ligand L(2-) (H(2)L = 3-(2-phenol)-5-(pyridin-2-yl)-1,2,4-triazole). Complexes 1 to 3 show a similar binuclear structure, with the central core of [Mn(II)Mn(III)(L)(2)] and some other small molecules also coordinated to the two Mn centers. The two [Mn(II)Mn(III)(L)(2)] subunits can be further connected by different dicarboxylic acids to construct non-charged tetranuclear complexes 4 to 7. In these complexes, each deprotonated dianionic ligand L(2-) acts as a mu(2)-bridged ligand to coordinate two Mn centers via the 1,2,4-triazole ring. Bond valence sum (BVS) calculations and Mn surrounding bond lengths indicate that the Mn center coordinated to the pyridine N atoms in the +2 oxidation state, while another Mn center coordinated to the phenolic O atoms is in the +3 oxidation state. The Mn(III) centre shows Jahn-Teller elongation along one of the axes. Magnetic studies show the presence of ferromagnetic Mn(III)-Mn(II) coupling in the binuclear (1-3) and tetranuclear (4-7) complexes with the magnetic coupling constant (J) ranging from 0.58 to 1.17 cm(-1), based on the Hamiltonian H = -2JS(1) x S(2) (S(1) = 5/2 and S(2) = 2). In all cases both z'J' (intermolecular interactions) and D parameter (Zero Field Splitting of the Mn (III) ion) has been introduced to improve the corresponding fit. The relationship of the coupling interaction between the Mn(II)/Mn(III) and their electronic structures is discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1477-9234
pubmed:author
pubmed:issnType
Electronic
pubmed:day
21
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10511-7
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Synthesis, structures and magnetic properties of polynuclear mixed-valence Mn(II)Mn(III) complexes containing 3-(2-phenol)-5-(pyridin-2-yl)-1,2,4-triazole ligand.
pubmed:affiliation
Department of Chenistry, Nankai University, Weijin Road 94, Tianjin, 300071, PR China.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't