1D, 2D, and 2D Parallel Interpenetrated Dicarboxylato Bridged Co(II) Metal Organic Frameworks: Synthesis, Crystal Structure, Fluorescence Sensing and Band Gap Calculation
Abstract
Metal organic frameworks of Co(II), {[Co(bphz)(1.5)(tp)(H2O)(2)]3.2H(2)O}(n) (1), {[Co(bphz)(ip)].(bphz)(0.5)}(n) (2), and [Co(bpp)(ppda)(H2O)(2)](n) (3) [where bphz=N,N '-bis-pyridin-4-ylmethylene-hydrazine; tp=1,4-benzenedicarboxylate; ip=1,3-benzenedicarboxylate; bpp=1,3-bis(4-pyridyl)propane; ppda=1,4-phenylenediacrylate] have been synthesized and characterized by single crystal X-ray diffraction and spectroscopic studies. Complex 1 is a ladder like 1D polymeric chain, 2 is a 2D porous sheet, while 3 is a 2D parallel interpenetrated network.
The band gap of complexes has been calculated using solid state reflectance spectra, and results show that complexes act as semiconductor. In dispersed methanolic solution complexes 1-3 exhibit intense fluorescence at room temperature.
The complexes were tested with several aromatic compounds such as benzene, nitrobenzene, o-nitrotoluene and p-nitrotoluene, etc., in dispersed methanol medium. Results show that complex 3 selectively senses nitro aromatic compounds and this behavior has been explained on the basis of PET and RET mechanisms.