Coordination Polymers of Copper and Zinc Ions with a Linear Linker Having Imidazole at Each End and an Azo Moiety in the Middle: Pedal Motion, Gas Adsorption, and Emission Studies

Abstract

The imidazole donor ligand bis(4-imidazol-1-ylphenyl)-diazene (azim) reacts readily with M(ClO 4 ) 2 •6H 2 O [M(II) = Zn(II) and Cu(II)] salts at room temperature to afford 4) are obtained in moderate yields. Complexes 1 and 2 crystallize as 2D fourconnected 4 4 sql networks with rectangular and rhombus grids, respectively. The frameworks are stabilized by an intricate array of hydrogen bonding interactions with guest molecules that also results in overall 3D frameworks. On the other hand, complexes 3 and 4 form 1D zigzag infinite chain structures. All compounds have been characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD) measurements. The TGA and PXRD measurements reveal that the integrity of the frameworks 1 and 2 is maintained upon guest removal. N 2 and CO 2 adsorption measurements were carried out for evacuated frameworks 1 and 2, and the adsorption studies show CO 2 selectivity over N 2 at low pressure in the case of 2. Interestingly, heat and guest induced bicycle pedal motion of the azo moiety can be observed in 1 and 4 without loss of crystallinity. Upon excitation at 304 nm, compounds 1−4 and 4′ exhibit solid-state luminescence at room temperature.

Structural Variety of Cobalt(II), Nickel(II), Zinc(II), and Cadmium(II) Complexes with 4,4′‐Azopyridine: Synthesis, Structure and Luminescence Properties

“…Metals such as Ni 2+ , Cu 2+ , and Co 2+ usually quench organic ligand luminescence; this is in contrast to the Zn 2+ and Cd 2+ ions, for which the effect is not present . As depicted in Figure , upon excitation at approximately λ =370 nm, two strong emission bands are observed at λ =466 and 494 nm with a weak emission band at λ =570 nm in azpy.…”

Syntheses, crystal structures and luminescent properties of six new d10 transitional metal coordination polymers based on bis(benzimidazole) ligands

“…3(a)). The formate comes from the hydrolysis of DMF under high pressure and temperature, which has been widely reported in the literature [32][33][34]. (Table S1).…”

Syntheses, Crystal Structure, and Luminescence Properties of Three Metal–Organic Compounds Bearing Diverse Dimensionalities Based on Mixed N- and O-Donor Organic Ligands

“…Organic-inorganic coordination polymers, especially those with d 10 metal centers, have been found to exhibit excellent luminescence properties and posses great potential applications as fluorescent-emitting materials [23][24][25][26][27][28]. Fluorescent properties of compounds 2, 3, and H 2 pip ligand were investigated in the solid state at room temperature and the emission spectra are depicted in Fig.…”