A Cd(ii) based 2D metal-organic framework (MOF), [Cd(4-bpd)(SCN)] (1) where 4-bpd = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene, has been synthesized and characterized by standard methods including single crystal X-ray diffraction analysis. When it is sandwiched between ITO coated glass and Al, 1 shows interesting conduction properties. The I-V characteristics of the ITO/1/Al configuration measured in the dark and under illumination of incident light exhibit a highly non-linear rectifying behavior, which signifies its Schottky diode character. The conductivity of the configuration is 2.90 × 10 S m and 7.16 × 10 S m under dark and photoirradiation conditions, respectively. Different parameters have been analyzed and these indicate that 1 can be a promising candidate for light sensing electronic devices. This material has good sensitivity to the light source when switched on/off. Theoretical calculations have been performed to understand the reason for the enhancement of conductivity under illumination of incident light. It has been found that upon irradiation, slight changes in the bond distances of 4-bpd in 1 occur. These changes are related to the considerable decrease in the energy needed for the allowed electronic transition. This may influence the increase of conductivity along with other factors.

The uncoordinated sulfur atom of the thiocyanato ligand of a 3D metallo-organic framework (MOF), [Ni(3-bpd)(NCS)] (1), where 3-bpd is 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, has been explored for selective visual detection and effective removal of Hg in aqueous medium. [Ni(3-bpd)(NCS)] has been synthesized under ambient conditions and characterized by elemental analysis, FT-IR spectroscopy, UV-vis spectroscopy, FE-SEM and EDX, XPS and X-ray single crystal diffraction analysis. 1 shows two thiocyanato moieties bound to the hexacoordinated metal center with N atoms whereas the sulfur end remains uncoordinated. The strategy for binding and removal of Hg is very simple. Hg is known for its affinity for strong bond formation with the soft center, S. The sulfur atoms form bonds with this heavy metal ion. The color of 1 changes from green to grey as Hg atoms form coordinate bonds with S atoms of the SCN group. It has been found that Hg is present in grey materials in a 2 : 1 ratio (Hg/Ni). 1 is selective for Hg as other metals/metalloids, including heavy metal ions, present in water are unable to change the color of 1 as they do not form any bond with it. Binding of Hg with the S end of the thiocyanato moiety has been confirmed by a number of techniques, e.g. IR and UV-vis spectra, FESEM, EDX, and XPS. Simple filtration is done to separate grey materials for the removal of Hg ion from the water medium. A theoretical calculation has been performed to rationalize the fact.

A novel cadmium(ii) based metal organic framework, [Cd(3-bpd)(SCN)2]n () where 3-bpd = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene has been synthesized and characterized by elemental analysis, various spectroscopic techniques, TGA and single crystal X-ray diffraction analysis. X-ray analysis shows the formation of an undulated polymeric two-dimensional network parallel to the (0 -1 1) plane. Current conduction properties of have been explored in the dark and in the presence of light. The study shows that current conduction of the complex increases with the increase of the incident light intensity. On progression of intensity of glancing radiation the photosensitivity of has been increased. The time dependent light response on charge carrier conduction reveals that complex may uncover new ground to explore in optoelectronic switching applications.

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