Gas-solid chemisorption of HCl and adsorption of MeOH/EtOH by nonporous chiral copper(II) coordination complexes 1·MeOH and 1″·MeOH occur in a cooperative and dynamic manner to give solvated second sphere adducts 1'·MeOH/EtOH. The chemisorption process involves dramatic atomic rearrangements in the crystalline state upon cleavage and formation of H-Cl, N-H, Cu-N, and Cu-Cl coordination and covalent bonds from the gas and solid state, respectively. Using mechanochemistry, the chloride-bridged coordination complex 1″·MeOH is selectively produced by means of a dehydrochlorination reaction, but not in solution in which a mixture of 1·MeOH and 1″·MeOH is obtained. 1″·MeOH also via chemisorption and adsorption can trap HCl and MeOH to give the second sphere adduct 1'·MeOH. The adsorption process is confirmed by forming the second sphere adduct 1'·EtOH by exposing both 1·MeOH and 1″·MeOH to HCl and ethanol. Quantum-mechanical (QM) calculations specific for solid phases give insights into the relative stabilities of the hybrid metal organic materials involved in the mechanochemical reaction producing selectively 1″·MeOH, giving a good agreement with the experimental results.

The aromatic ligand 4,4′-(1,3-phenylenedioxy)-dianiline (L), has been used to explore its coordination chemistry behaviour and nitroaromatic sensing ability by crystallizing it with a variety of transition metals. The supramolecular structures [CuCl 2 (L)] (1), [Mn(H 2 O) 2 Cl 2 (L) 2 ] (2), [Ni(H 2 O) 2 (L) 2 ] Cl 2 (3) and [Co(H 2 O) 2 (L) 2 ] Cl 2 (4) have been characterized by single crystal X-ray diffraction (SC-XRD) and X-ray powder diffraction (XRPD) analysis. While 1 and 2 do not form polymeric structures but discrete (0D) arrays, 3 and 4 resulted in extended isostructural 2D coordination polymers. The solid-state fluorescence properties of the reported crystals have been investigated. Interestingly, coordination polymers 3 and 4 showed a better solid-state fluorescence emission compared to that of complexes 1 and 2. Coordination polymer 3 has been successfully used as a sensor for the detection of trace amounts of nitrobenzene, 2-nitrotoluene and 3-nitrotoluene with a high quenching efficiency of 96% for 3-nitrotoluene. The quenching efficiency of 3 is better than that of the free ligand L. The polymeric nature of 3 is maintained after the sensing experiment and thus can be used in a recyclable manner. Due to the fact that 3 is a nonporous and its structure does not change in the presence of the quenchers, the quenching effect occurs in the surface of the solids when is in a suspension.