期刊
DALTON TRANSACTIONS
卷 41, 期 2, 页码 413-423出版社
ROYAL SOC CHEMISTRY
DOI: 10.1039/c1dt11458a
关键词
-
资金
- Department of Science & Technology (DST), New Delhi, India [SR/S1/IC-27/2008]
- University Grants Commission, New Delhi, India
- DST
- Fundacio Catalana per a la Recerca (FCR)
- Universitat de Barcelona
- [CTQ2009-07264/BQU]
- [CTQ2008-06670-C02-01]
- [2009 SGR-1454]
- [2009SGR-1459]
The ditopic ligand PyPzOAPz (N-[(Z)-amino(pyrazin-2-yl)methylidene]-5-methyl-1-(pyridin-2-yl)-1H-pyrazole-3-carbohydrazonic acid) was synthesized by in situ condensation of methyl imino pyrazine-2-carboxylate with 5-methyl-1-(2-pyridyl) pyrazole-3-carbohydrazide. In this work we have also used two of our earlier ligands PzCAP (5-methyl-N-[(1E)-1-(pyridin-2-yl) ethylidene]-1H-pyrazole-3-carbohydrazonic acid) (Dalton Trans., 2009, 8215) and PzOAP (N-[(Z)-amino(pyridin-2-yl) methylidene]-5-methyl-1H-pyrazole-3-carbohydrazonic acid) (Dalton Trans., 2007, 1229). These ligands PzCAP, PzOAP and PyPzOAPz were made to react with Mn(ClO4)(2)center dot 6H(2)O to produce three pentanuclear Mn(II) clusters [Mn-5(PzCAP)(6)](ClO4)(4) (1), [Mn-5(PzOAP)(6)](ClO4)(4) (2) and [Mn-5(PyPzOAPz)(6)](ClO4)(4) (3). These complexes have been characterized by X-ray structural analyses and variable temperature magnetic susceptibility measurements. All complexes have a pentanuclear core with trigonal bipyramidal arrangement of Mn(II) atoms, where, the axial metal centers have a N3O3 chromophore and the equatorial centers have N4O2 with an octahedral arrangement. These Mn-5(II) clusters 1, 2 and 3 show the presence of antiferromagnetic coupling within the pentanuclear manganese(II) core (J = -2.95, -3.19 and -3.00 cm(-1) respectively). Density functional theory calculations and continuous shape measurement (CShM) studies have been performed on these complexes to provide a qualitative theoretical interpretation of the antiferromagnetic behaviour shown by them. The pentanuclear Mn(II) cluster (1) on reaction with Cu(NO3)(2)center dot 6H(2)O in 1 : 1 mole proportion in CH3OH:H2O (60 : 40) forms a homoleptic [2 x 2] tetranuclear Cu-4(II) grid [Cu-4(PzCAP)(4)(NO3)(2)](NO3)(2)center dot 8H(2)O (4). The same Cu-4(II) grid is also obtained from a direct reaction between the ditopic ligand PzCAP with Cu(NO3)(2)center dot 6H(2)O in 1 : 1 mole proportion. This conversion of a cluster to a grid is a novel observation.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据