Tuning the silver(l) complexes of 3-(2-pyridyl)pyrazole-based ligands: Syntheses and crystal structures of the complexes, as well as theoretical investigations on the coordination abilities of the ligands

In our efforts to investigate the influences of different pendant aromatic groups and the spatial position of N donors in 3-(2-pyridyl)pyrazole-based ligands on the structures of their metal complexes, five structurally related ligands: 1-[3-(2-pyridyl)pyrazol- 1-ylmethyl]benzene (L-1), 1-[3-(2-pyridyl) pyrazol-1-ylmethyl]naphthalene (L-2), 8-[3-(2-pyridyl)pyrazol-1-ylmethyl]quinoline (L-3), 3-[3-(2-pyridyl)pyrazol-1-ylmethyl]pyridine (L-4) and 4-[3-(2- pyridyl)pyrazol-1-ylmethvl]pyridine (L-5), have been used to react with AgCl4 to form five Ag(I) complexes, [Ag(L-1)(2)](ClO4) (1), [Ag(L-2)(2)](ClO4) (2), [Ag(L-3)(HL3)](ClO4)(2)(CH3CN) (3), {[Ag(L-4)](ClO4)}(2) (4), and {[Ag(L-5)]ClO4)}(infinity) (5). The structural differences of these complexes may be attributed to the coordination geometries or N donor position of the pendant aromatic groups in ligands L-1-L-5. Also, the result reveals that various intra- and/or inter-molecular weak interactions, such as pi center dot center dot center dot pi stacking, C-H center dot center dot center dot pi and C-H center dot center dot center dot O H-bonding interactions, play important roles in the formation of 1-5, especially in the aspect of linking the multi-nuclear discrete subunits or low-dimensional entities into high-dimensional frameworks. Moreover, the coordination behaviors of ligands L-1-L-5 have been briefly evaluated by DFT calculations. (c) 2007 Elsevier B.V. All rights reserved.