title: A noninterpenetrated 1D molecular ladder and 2D butterfly network: effect of positional isomerism of semirigid bis(pyridylmethyl)pyromellitic diimide ligands on the architecture of their metal(II) complexes.
abstract: Three new complexes [Cd(4-pmpmd)1.5 (NO3)2] x CHCl3 (1), [Cd(3-pmpmd)1.5 (NO3)2] x EtOH (2), and [Zn(3-pmpmd)1.5 (NO3)2] x MeOH (3) (3- or 4-pmpmd = N,N'-bis(3- or 4-pyridylmethyl)pyromellitic diimide) containing T-shaped building blocks have been obtained from reactions between the long semirigid ligands 3- or 4-pmpmd and either cadmium or zinc nitrate. 1 forms noninterpenetrated 1D molecular ladders that are linked via multiple, complementary intermolecular C-H...O hydrogen bonds that effect the 3D alignment. 2 and 3 are isostructural and feature a noninterpenetrated 2D butterfly-shaped network with (6,3) topology. Multiple intermolecular C-H...O hydrogen bonds exist between the 2D layers and generate the 3D framework. The structural differences between 1 and 2 or 3 are attributed to the different conformations adopted by the ligands, which illustrate the influence of positional isomerism on the resultant supramolecular architectures of metal complexes.
authors.affiliation: School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Xing-Qiang
authors.initials: XQ
authors.lastname: Lü
authors.forename: Ji-Jun
authors.initials: JJ
authors.lastname: Jiang
authors.forename: Hans-Conrad
authors.initials: HC
authors.lastname: zur Loye
authors.forename: Bei-Sheng
authors.initials: BS
authors.lastname: Kang
authors.forename: Cheng-Yong
authors.initials: CY
authors.lastname: Su