The two isostructural one-dimensional coordination polymers (1D CPs) [Cu­(5-nip)­(3-Clpy)2] n (1) and [Cu­(5-nip)­(3-Brpy)2] n (2) have been synthesized using a 5-nitroisophthalic acid (H25-nip) linker and the meta-substituted 3-chloropyridine (3-Clpy)/3-bromopyridine (3-Brpy) auxiliary ligands. The structural architectures and supramolecular interactions of the CPs have been investigated by single-crystal X-ray diffraction (SCXRD) and density functional theory (DFT) studies, respectively. The SCXRD study reveals that CPs 1 and 2 form a 1D double-chain structure with carboxylato-bridged cyclic secondary building units (SBUs). Interestingly, both CPs involve type I halogen···halogen (X···X) interactions combined with π···π stacking interactions to generate a three-dimensional (3D) supramolecular network. Moreover, both CPs exhibit interesting X···N π-hole interactions involving a nitro group as the electron acceptor. Both CPs show electrical conductivity in the semiconducting regime and behave as Schottky diodes. However, CP 1 has a higher electrical conductivity in comparison to CP 2.

Schottky behaviour was tuned by altering para-substituents on benzoate ligands in two isostructural Zn(ii)-based 1D coordination polymers.

A Zn(II) based one-dimensional (1D) coordination polymer (CP), [Zn(cis-1,4-chdc)(4-nvp)] (1) {cis-1,4-H2chdc = cis-1,4-cyclohexanedicarboxylic acid and 4-nvp = 4-(1-naphthylvinyl)pyridine} undergoes solid-state photochemical [2+2] cycloaddition reaction acompanied by mechanical motion, wherein crystals...

Four new pyridine/meta-substituted halopyridine appended coordination polymers (CPs) {[Cu(ip) 6 (py and [Cu(ip) 2 (3-Ipy) 2 ] n (4) (py = pyridine, 3-Clpy = 3chloropyridine, 3-Brpy = 3-bromopyridine, 3-Ipy = 3-iodopyridine, and H 2 ip = isophthalic acid) have been synthesized by a diffusion method. The compounds are structurally characterized by the single crystal X-ray diffraction technique, and supramolecular interactions are studied by geometrical and density functional theory calculations. The study reveals that the compounds 1−3 form a two-dimensional (2D) coordination polymeric structure with carboxylato bridged dimeric Cu(II) cyclic secondary building units. However, a cyclic supramolecular synthon involving four halogen (X = Cl, Br) atoms has been observed in 2 and 3. This cyclic halogen synthon combined with a pyridine ring forms a (π•••π)+X•••X+(π•••π) mega-synthon, which dictates the dimensionality of 2D CPs into a three-dimensional (3D) network. However, compound 4 with a larger I atom does not show such interactions and forms a 1D tape structure.

Dynamic photoactuating crystals have become a sensation due to their potential applications in developing smart medical devices, molecular machines, artificial muscles, flexible electronics actuators, probes and microrobots. Here we report the synthesis of two iso-structural metal-organic crystals, [Zn(4-ohbz)2(4-nvp)2] (1) and [Cd(4-ohbz)2(4-nvp)2] (2) {H4-ohbz = 4-hydroxy benzoic acid; 4-nvp = 4-(1-naphthylvinyl)pyridine} which undergo topochemical [2 + 2] cycloaddition under UV irradiation as well as sunlight to generate a dimerized product of discrete metal-complex [Zn(4-ohbz)2(rctt-4-pncb)] {rctt-4-pncb = 1,3-bis(4′-pyridyl)-2,4-bis(naphthyl)cyclobutane} (1′) and one-dimensional coordination polymer (1D CP) [Cd(4-ohbz)2(rctt-4-pncb)] (2′) respectively, in a single-crystal-to-single-crystal (SCSC) process. The Zn-based compound demonstrates photosalient behaviour, wherein crystals show jumping, splitting, rolling, and swelling upon UV irradiation. However, the Cd-based crystals do not show such behaviour maintaining the initial supramolecular packing and space group. Thus the photomechanical behaviour can be induced by choosing a suitable metal ion. The above findings are thoroughly validated by quantitative density functional theory (DFT) calculations which show that the Zn-based crystal shifts towards an orthorhombic structure to resolve the anisotropic UV-induced mechanical strain. Furthermore, the mechano-structure-property relationship has been established by complimentary nanoindentation measurements, which are in-line with the DFT-predicted single crystal values.

Two isotypical Co(ii)-based 1D coordination polymers with a linear ditopic linker along with pyridyl based ligands exhibit optoelectronic property.

We synthesized two Zn(ii)-based 1D coordination polymers with paddle-wheel units using flexible 1,4-cyclohexanedicarboxylate linkers; these compounds exhibited electrical conductivity and Schottky barrier diode behavior.

Four new Cu(II)-based hexagonal complexes with the metallomacrocycle formulae [Cu6(5-nip)6(3-py)6(H2O)12] (1), [Cu6(5-nip)6(3-Clpy)6(H2O)12] (2), [Cu6(5-nip)6(3-Brpy)6(H2O)12] (3), and [Cu6(5-nip)6(3-Ipy)6(H2O)12] (4) have been synthesized using 5-nitroisophthalic acid (H25-nip) and pyridine (py)/3-halopyridine (3-Xpy; X = Cl, Br, and I) ligands. The structural features and supramolecular interactions of compounds 1–4 have been investigated using the single-crystal X-ray diffraction (SCXRD) technique. Interestingly, the hexagonal complexes undergo hydrogen bonding and π···π stacking interactions to form fascinating two-dimensional (2D) honeycomb-like structures. The synthesized complexes exhibit high electrical conductivity, arising from charge transport through space via π···π contacts. However, complexes containing 3-Brpy (3) and 3-Ipy (4) exhibit photosensitivity due to the presence of halogens with a larger size and lower ionization energy. The conductivity results are also in accordance with the theoretical prediction calculated by density functional theory (DFT) study.