Synthesis of one- and two-dimensional coordination polymers containing organotin macrocycles. Reactions of (n-Bu _3Sn) _2O with pyridine dicarboxylic acids. Structure-directing role of the ancillary 4,4′-bipyridine ligand

摘要

The reaction of (n-Bu 3Sn) 2O with pyridine-2,6- dicarboxylic acid (L1H 2) in a 1:1 ratio resulted in the formation of a one-dimensional (1D) coordination polymer [(n-Bu _3Sn) _2(n-Bu _2Sn) _2(μ-L1) _2(μ-OH) _2] _n (1). The formation of 1 is accompanied by a Sn-butyl bond cleavage reaction involving half of the organotin units. The formation of the 1D coordination polymer is facilitated by the multisite coordination capability of the dianionic ligand L1. The reaction of (n-Bu _3Sn) _2O with pyridine-2,5-dicarboxylic acid (L2H _2) or pyridine-3,5-dicarboxylic acid (L3H _2), on the other hand, results in the generation of the two-dimensional (2D) coordination polymers [(n-Bu _3Sn) _2(μ-L2)] _n (2) and [(n-Bu _3Sn) _4(μ-L3) _2] _n (3), respectively. The formation of 2 and 3 emphasizes the importance of the relative orientation of the coordinating units in the multisite coordination ligand. Compounds 1-3 show a rich supramolecular architecture in their solid state as a result of multiple secondary interactions. Investigation of the fate of the reactions of (n-Bu _3Sn) _2O with pyridine dicarboxylic acids in the presence of a bridging ligand was carried out. In all the cases when the reactions were carried out in the presence of 4,4′-bipyridine (4,4′-bipy), 1D coordination polymers [(n-Bu _3Sn) _2(μ-L1)(μ-4,4′-bipy)] _n (4), [(n-Bu 3Sn) 2(μ-L3)(μ-4,4′-bipy)] _n (5), and [(n-Bu 3Sn) 2(μ-L2)(μ-4,4′-bipy)] _n (6) are formed. In these cases, the 4,4′-bipyridine ligand serves as one of the connectors that link the organotin units. Interestingly, in the presence of 4,4′-bipyridine, Sn-butyl bond cleavage does not take place. While the 1D coordination polymers 4 and 5 form three-dimensional supramolecular architectures in their solid state, compound 6 possesses a 2D supramolecular architecture.