Xie Ya-Bo, Zhang Chong, Li Jian-Rong, Bu Xian-He
Department of Chemistry, Nankai University, Tianjin, PR China.
Dalton Trans. 2004 Feb 21(4):562-9. doi: 10.1039/b315320g. Epub 2004 Jan 26.
The reactions of four flexible tetradentate ligands, 1,3-bis(2-pyridylthio)propane (L1), 1,4-bis(2-pyridylthio)butane (L2), 1,5-bis(2-pyridylthio)pentane (L3) and 1,6-bis(2-pyridylthio)hexane (L4) with AgX (X = BF4-, ClO4-, PF6-, or CF3SO3-) lead to the formation of seven new complexes: [AgL1(BF4)]2 (1), [AgL2]infinity (2), [AgL2(CH3CN)]infinity (3), [AgL3(CHCl3)]2 (4), [AgL3(CF3SO3)(0.5)]infinity (5), [Ag2L4(2)2]infinity (6), and [AgL4]infinity (7), which have been characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. Single-crystal X-ray analyses show that complexes 1 and 4 possess dinuclear macrometallacyclic structures, and complexes 2, 3 and 5-7 take chain structures. In all the complexes, the nitrogen atoms of ligands preferentially coordinate to silver atoms to form normal coordination bonds, while the sulfur atoms only show weak interactions with silver atoms and the intermolecular AgS weak contacts connect the low-dimensional complexes into high-dimensional supramolecular networks. Additional weak interactions, such as pi-pi stacking, F...F weak interactions, Ag...O contacts or C-H...O hydrogen bonds, also help to stabilize the crystal structures. It was found that the parity of the -(CH2)n- spacers (n = 3-6) affect the orientation of the two terminal pyridyl rings, thereby significantly influence the framework formations of these complexes. The coordination features of ligands and their conformation changes between free and coordination states have been investigated by DFT calculations.
四种柔性四齿配体,1,3 - 双(2 - 吡啶硫基)丙烷(L1)、1,4 - 双(2 - 吡啶硫基)丁烷(L2)、1,5 - 双(2 - 吡啶硫基)戊烷(L3)和1,6 - 双(2 - 吡啶硫基)己烷(L4)与AgX(X = BF4-、ClO4-、PF6-或CF3SO3-)反应生成了七种新配合物:[AgL1(BF4)]2(1)、[AgL2]∞(2)、[AgL2(CH3CN)]∞(3)、[AgL3(CHCl3)]2(4)、[AgL3(CF3SO3)(0.5)]∞(5)、[Ag2L4(2)2]∞(6)和[AgL4]∞(7),这些配合物已通过元素分析、红外光谱和X射线晶体学进行了表征。单晶X射线分析表明,配合物1和4具有双核大环金属环结构,配合物2、3和5 - 7具有链状结构。在所有配合物中,配体的氮原子优先与银原子配位形成正常配位键,而硫原子仅与银原子表现出弱相互作用,分子间的AgS弱接触将低维配合物连接成高维超分子网络。其他弱相互作用,如π - π堆积、F...F弱相互作用、Ag...O接触或C - H...O氢键,也有助于稳定晶体结构。研究发现,-(CH2)n-间隔基(n = 3 - 6)的奇偶性影响两个末端吡啶环的取向,从而显著影响这些配合物的骨架形成。通过密度泛函理论计算研究了配体的配位特征及其在游离态和配位态之间的构象变化。