dlf Complexes with Uniform Coordination Geometry: Structural and Magnetic Properties of an LnNi2 Core Supported by a Heptadentate Amine Phenol Ligand
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- 作者：Simon R. Bayly ; Zhiquiang Xu ; Brian O. Patrick ; Steven J. Rettig ; Maren Pink ; Robert C. Thompson ; and Chris Orvig
- 刊名：Inorganic Chemistry
- 出版年：2003
- 出版时间：March 10, 2003
- 年：2003
- 卷：42
- 期：5
- 页码：1576 - 1583
- 全文大小：141K
- 年卷期：v.42,no.5(March 10, 2003)
- ISSN：1520-510X
文摘
The synthesis and physical characterization of a series of lanthanide (LnIII) and nickel (NiII) mixed trimetallic complexeswith the heptadentate (N4O3) amine phenol ligand H3trn [tris(2'-hydroxybenzylaminoethyl)amine] has beenaccomplished in order to extend our understanding of how amine phenol ligands can be used to coaggregate d-and f-block metal ions and to investigate further the magnetic interaction between these ions. The one-pot reactionin methanol of stoichiometric amounts of H3trn with NiX2·6H2O (X = ClO4, NO3) followed by addition of thecorresponding LnX3·6H2O salt, and then base, produces complexes of the general formula [LnNi2(trn)2]X·nH2O.The complexes were characterized by a variety of analytical techniques. Crystals of five of the complexes weregrown from methanol solutions and their structures were determined by X-ray analysis: [PrNi2(trn)2(CH3OH)]ClO4·4CH3OH·H2O, [SmNi2(trn)2(CH3OH)]NO3·4CH3OH·2H2O, [TbNi2(trn)2(CH3OH)]NO3·4CH3OH·3H2O, [ErNi2(trn)2(CH3OH)]NO3·6CH3OH, and [LuNi2(trn)2(CH3OH)]NO3·4.5CH3OH·1.5H2O. The [LnNi2(trn)2(CH3OH)]+ complex cation consistsof two octahedral NiII ions, each of which is encapsulated by the ligand trn3- in an N4O2 coordination sphere withone phenolate O atom not bound to NiII. Each [Ni(trn)]- unit acts as a tridentate ligand toward the LnIII ion via twobridging and one nonbridging phenolate donors. Remarkably, in all of the structurally characterized complexes,LnIII is seven-coordinate and has a flattened pentagonal bipyramidal geometry. Such uniform coordination behavioralong the whole lanthanide series is rare and can perhaps be attributed to a mismatch between the geometricrequirements of the bridging and nonbridging phenolate donors. Magnetic studies indicate that ferromagnetic exchangeoccurs in the NiII/LnII complexes where Ln = Gd, Tb, Dy, Ho, or Er.