| Hierarchical Structures in Tin(II) Oxalates (2008) | |||||||||
Abstract | |||||||||
| Six new $Sn^{II}$ oxalates exhibiting a hierarchy of structures have been prepared employing hydrothermal methods. The compounds I $[C_{10}N_2H_{10}][Sn(C_2O_4)_2]$, II $[C_{10}N_2H_{10}][Sn_2(C_2O_4)_3]$, and III $[C_8N_4H_{26}][Sn(C_2O_4)_2]_2.2H_2O$ possess zero-dimensional molecular structures; IV $[C_{10}N_2H_8]_2[Sn(C_2O_4)]_2$ and V $[C_{12}N_2H_8][SnC_2O_4]$ have one-dimensional chain structures; and compound VI $[C_5N_2H_{14}]_2[Sn_4(C_2O_4)_6]ยท7H_2O$ has a two-dimensional layer structure. The SnII ions have 4- and 6-coordination with square-pyramidal or pentagonal-bipyramidal geometry, in which the lone pair of electrons also occupies one of the vertices. Weak intermolecular forces such as hydrogen-bond interactions, \pi ... \pi interactions, and lone-pair- \pi interactions have been observed and appear to lendstructural stability. Theoretical studies indicate that the \pi ... \pi interaction energy between the bound 1,10-phenanthroline molecules is of the order of 5-6 kcal mol-1 in V. Natural bond orbital (NBO) analysis on two model compounds, II and IV, indicates reasonable lone-pair- \pi interactions. The close structural relationship between all the compounds indicates that a building-up process from the zero-dimensional monomer can be considered. The present structures provide opportunities for evaluating the structure-directing role of the lone pair of electrons of $Sn^{II}$ | |||||||||
Publication details | |||||||||
| |||||||||