- A new structural form of tin in a double O-capped cluster
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Two new cyanorhenate complexes of potential utility in constructing magnetic and photomagnetic materials are reported. Reaction of (Bu4N)CN with [ReCl6]2- in acetonitrile affords yellow (Bu4N)3[Re(CN)7] (1), featuring the pentagonal bipyramidal complex [Re(CN)7]3-. The spectral and magnetic properties of 1 indicate that the complex has an S = 1/2 ground state with considerable anisotropy in the g tensor. In aqueous solution, 1 reacts with Mn2+ ions to generate the three-dimensional cyano-bridged solid [fac-Mn(H2O)3][cis-Mn(H2O)2][Re(CN)7]·3H2O (2) containing diamagnetic [Re(CN)7]4-. Addition of KIO4 to the reaction solution, originally intended to prevent reduction of the rhenium during solid formation, instead yields white (Bu4N)3[Re(CN)8] (3). As crystallized in K3[Re(CN)8]·2MeCN (4·2MeCN), the diamagnetic [Re(CN)8]3- complex adopts a nearly perfect square antiprismatic coordination geometry. In solution, this species behaves analogously to the isoelectronic [M(CN)8]4- (M = Mo, W) complexes, apparently converting to a dodecahedral geometry and photooxidizing under UV radiation to give paramagnetic [Re(CN)8]2-. Copyright
- Chandrasekhar, Vadapalli,Baskar, Viswanathan,Vittal, Jagadese J.
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- Organooxotin cages, {[(n-BuSn)3(μ3-O)(OC6H 4-4-X)3]2[HPO3]4}, X = H, Cl, Br, and I, in double O-capped structures: Halogen-bonding-mediated supramolecular formation
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The reaction of n-BuSn(O)(OH) with H3PO3 and HOC 6H4-4-X (X = H, Cl, Br, and I) afforded the hexanuclear organooxotin cages {[(n-BuSn)3(μ3-O)(OC 6H4-4-X)3]2[HPO3] 4}, where X = H (1), Cl (2), Br (3), and I (4), in moderate yields. These cages possess double O-capped structures. The oxotin cages 1-4 contain two tritin motifs that are joined by four tripodal [HPO3]2- ligands. The three tin atoms in each tritin subunit are held together by a μ3-capping oxygen atom. In addition three phenolate oxygen atoms act as μ2-bridging ligands between two tin atoms. The molecular structures of 1-4 are intimately related to other organooxotin cages such as the O-capped cluster, the drum, and the football cage. The crystal structures of 2-4 reveal intermolecular halogen-bonding-mediated [X- - -O (X = Cl, Br), I- - -I, and I- - π] supramolecular assemblies.
- Chandrasekhar, Vadapalli,Baskar, Viswanathan,Gopal, Kandasamy,Vittal, Jagadese J.
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p. 4926 - 4932
(2008/10/09)
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