Building-up novel coordination polymer with Zn(II) porphyrin dimer: Synthesis, structures, surface morphology and effect of axial ligands

Abstract

Highly flexible Zn(II)1,2-bis(meso-octaethylporphyrin)ethane (1) has been used as host in which two porphyrin rings are found to be face-to-face in non-coordinating solvents. Upon addition of one relatively smaller 4,4′-dipyridine (L1) and one extended N,N′-bispyridine-4-yl-methylene ethylenediamine (L2) guest ligands, the syn conformation of 1 is switched to the anti complexes 1∙(L1)2 and 1∙L 2, respectively. Single crystal X-ray structures of all the complexes are reported in which a stable one-dimensional coordination polymer is produced only in 1∙L 2 that is, to the best of our knowledge, the first structural report of 1D-coordination polymer with porphyrin dimer. Solution structures of the complexes along with binding studies in solution between 1 and L have also been investigated. The morphology of the polymeric complex 1∙L 2 on silicon wafer surface was examined by Atomic Force Microscopy (AFM) in which the crystalline islands of well defined facets of size ranging from 200–550 nm perimeter and a height of 20–40 nm have been observed. Highly flexible Zn(II)bisporphyrin, which is found to be cofacial, forms a stable 1D coordination polymer with N,N′-bispyridine-4-yl-methylene ethylenediamine which, on silicon wafer surface, produces crystalline islands of well defined facets of size ranging from 200–550 nm perimeter and a height of 20-40 nm.