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摘要
The complexes [Ag-2(L)(2)(SO4)](infinity), (L = 2-aminopyrimidine) 1, [ Ag(L)(1.5)(ClO4)](infinity), 2, and [Ag(L)(OAc)center dot 2H(2)O](infinity), 3, were prepared by layering the aqueous solution of the corresponding Ag(I) salt with L in ethanol, while [Ag(L')(NO3)](infinity), 4, and [Ag(L')(ClO4)center dot H2O](infinity), 5, were prepared by refluxing AgNO3 and AgClO4, respectively, with 2-amino-4,6-dimethylpyrimidine (L') in H2O. Reaction of Ag2SO4 with L' in methanol afforded the complex [Ag-4(L')(2)(SO4)(2)(H2O)(4)](infinity), 6. In complex 1, the L ligands are coordinated to the Ag( I) metal centers in new tridentate fashions, forming 2-D pleated molecular sheets which are interlinked by the SO42- anions to form a 3-D layer structure. Complex 2 forms a pleated molecular sheet consisting of twenty four-membered metallocycles, involving six Ag ions which are bridged by six L ligands through the pyrimidyl nitrogen atoms. Complex 3 forms linear chains with sinusoidal geometry, which are interlinked through extensive (AgAg)-Ag-... interactions ((AgAg)-Ag-... = 3.102 angstrom) to form 2-D wavy rectangular grids. Complex 4 forms single-strained helical coordination polymers, which are interlinked through a series of (AgO)-O-... interactions (2.667 and 2.699 angstrom) to form 2-D chair like grids. The silver atoms of 5 are bound to the nitrogen atoms of two symmetry-related L' ligands in a distinctly non-linear geometry, forming zigzag chains. The structure of 6 consists of clusters of the formula [Ag8(L')(4)(SO4)(4)(H2O)(8)], which are interlinked through L' ligands to form 2-D sheets. The mu(1)-O, mu(2)-O'- bonding mode of the SO42- anion in complex 6 is unique for Ag(I) complexes. Their thermal properties have been investigated by using differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA).
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