- Ni3versus Ni30: A Truncated Octahedron Metal–Organic Cage Constructed with [Ni5(CN)4]6+Squares and Tripodal Tris-tacn Ligands That are Large and Flexible
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Reactions of trinickel complex of tripodal tris-tacn ligand N(CH2-m-C6H4-CH2tacn)3(L, tacn=1,4,7-triazacyclononane) in acetonitrile–methanol solution with and without phosphate led to two complexes of distinct nuclearities, [(NiIICl)3(CH3OH)3(HPO4)L](PF6) (Ni3, 1) and [(NiII5(CN)4(H2O)8Cl)6L8]Cl30(Ni30, 2). Ligand L takes upward and downward conformation in the structure of 1 and 2, respectively. It is proposed that phosphate directs the upward conformation of Ni3L to form 1. In the absence of phosphate, Ni3L assembles with cyanide ions, which are formed by Ni-catalyzed C?CN bond cleavage of acetonitrile, to give a nano-sized Ni30cage. Complex 2 represents a discrete truncated octahedron cage assembled with [Ni5(CN)4]6+squares and large and flexible triangular ligands, which is scarcely observed for self-assembled metal-organic cages. The magnetic properties of 1 and 2 were examined, showing intriguing magnetic properties.
- Zhang, Zongyao,Zheng, Kunyi,Xia, Tianlong,Xu, Lijin,Cao, Rui
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supporting information
p. 17576 - 17580
(2016/11/28)
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- Tripodal tris-tacn and tris-dpa platforms for assembling phosphate-templated trimetallic centers
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Multidentate tripodal ligands, N(CH2-m-C6H 4-CH2tacn)3 (L1) and N(CH2-o-C 6H4-CH2N(CH2py)2) 3 (L2), have been devised for assembling high-nuclearity metal clusters. By using the same tripodal platform with different ligand appendages, either triazacyclononanes or dipicolylamines, and functionalizing either the ortho or the meta positions on the tris(xylyl) linker arms, discrete trimetal phosphate units of relevance to phosphate-metabolizing trimetallic centers in biology were prepared. Four such compounds, [(CuIICl) 3(HPO4)L1](PF6) (1), [(CuIICl) 3(HAsO4)L1](PF6) (2), Na2[Mn III6MnII2(H2O) 2(HPO4)6(PO4)4(L1) 2] (3), and [CoII3(H2PO 4)Cl2(MeCN)L2](PF6)3 (4), all containing three metal centers bound to a central phosphate or arsenate unit bridging oxygen atoms, have been synthesized and structurally characterized. These results demonstrate the propensity of this novel tripodal ligand platform, in the presence of phosphate or arsenate, to assemble {M3(EO 4)} units and thus structurally mimic trimetallic active sites of proteins involved in phosphate metabolism. Reactivity studies reveal that the tricopper complex 1 is more efficient than monocopper analogues in catalyzing the hydrolysis of 4-nitrophenyl phosphate.
- Cao, Rui,Mueller, Peter,Lippard, Stephen J.
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supporting information; experimental part
p. 17366 - 17369
(2011/02/23)
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