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Development of multifunctional organic materials is an area of intense research interest in organic materials chemistry. This study reports the synthesis, crystal structure elucidation and investigation of multiple properties of E-3-pyridylvinyl benzoxazole (3-PVBO) and its methylated analogue, 3-MPVBO. With Z′ = 2, 3-PVBO belongs to a rare class of crystals for which Z′ > 1. Upon methylation, fascinating material properties were observed. [3-MPVBO]I exhibited strong emission spectra and readily available redox states. It exhibited stronger emission at 474 nm, with a larger Stokes shift of 8900 cm−1, than the emission of 3-PVBO at 386 nm, with a Stokes shift of 5450 cm−1. Upon exposure to UV light, crystals of 3-PVBO underwent a solid-state photodimerization reaction in a head-to-tail fashion (HT), leading to the formation of the HT-rctt isomer of the dimer, i.e., 1,3-bis(benzoxazole)-2,4-bis(3-pyridyl)cyclobutane (PBOCB). Herein, the crystal structure, solid-state photoreactivity, and multiple material properties, e.g., photophysical and electrochemical properties, are presented. [ABSTRACT FROM AUTHOR]

Reactions of a photostable bidentate ligand trans-5-styrylpyrimidine (5-Spym) with various silver(I) salts resulted in the formation of coordination polymers (CPs) of composition {[Ag(5-Spym)(H2O)](NO3)} (1), {[Ag(5-Spym)(H2O)](BF4)} (2), {[Ag(5-Spym)](SbF6)} (3), {[Ag(5-Spym)(CF3SO3)]} (4), and {[Ag(5-Spym)(CF3CO2)]} (5). The first four CPs (1–4) were found to be one-dimensional (1D) zigzag coordination polymers, where 5-Spym ligands from the neighbouring chains assembled in an infinite parallel arrangement in a head-to-tail fashion. These CPs exhibited [2 + 2] photocycloaddition reaction in the solid state upon exposure to sunlight. On the other hand, the structure of 5 was determined to be a two-dimensional (2D) coordination polymer, and it was found to be photostable. In these series of compounds, the coordination number of Ag(I) varied from 2 to 4, and the coordination geometries were observed to be linear, T-shaped, trigonal, square planar and distorted tetrahedral. By varying the counteranions in the silver(I) salts, various coordination numbers and geometries, and thus structural diversity, and various solid-state photo-reactivities were observed. The scope of mechanochemistry in accessing these CPs is also discussed. Various types of intermolecular interactions observed in this series of compounds have been verified by analyses of their Hirshfeld surfaces. [ABSTRACT FROM AUTHOR]

We have synthesized a biphenyl-derived two arm-containing amido Schiff base, bis((2-hydroxynaphthalen-1-yl) methylene)-[1,1′-biphenyl]-2,2′-dicarbohydrazide (sensor 1), having hard donors to facilitate chelation with hard metal centers. The crystal structure of sensor 1 reveals that it crystallizes in the monoclinic system with the space group I2/a and shows several types of intra/inter-molecular H-bond interactions, which stabilized the crystal lattice. The sensing property of sensor 1 towards different metal ions has been demonstrated using different analytical techniques. In fact, sensor 1 shows high fluorescence selectivity and sensitivity towards Al3+ ions in aqueous DMF media. Importantly, we have reported the first structurally characterized six-coordinate dinuclear Al3+ complex ([Na(Al2L2)·2H2O·4DMF], complex 1 (where ligand, L = sensor 1). Complex 1 crystallizes in the space group P1¯. X-ray single crystal diffraction studies for complex 1 reveal that each Al3+ ion is hexa-coordinated by four oxygen and two nitrogen atoms from each arm of the two ligands. The sodium ion has penta-coordination in a highly distorted trigonal bipyramidal geometry, surrounded by two μ-bridging naphtholate oxygen atoms and three solvent DMF oxygen atoms. Upon addition of Na2EDTA to complex 1, no spectral change or naked-eye colour change was observed. Furthermore, "test kits" coated with sensor 1 showed successful selective detection of Al3+ ions under UV light. [ABSTRACT FROM AUTHOR]

Solid-state photochemical [2 + 2] cycloaddition reaction is one of the promising routes to isolate highly strained cyclobutane derivatives, which may otherwise be very difficult to obtain via conventional synthetic methodology. Various methods have been developed to align the olefins in crystalline materials for the fabrication of cyclobutane derivatives. However, the separation of cyclobutane ligands from the photo-product has not been much explored. In this highlight, a variety of functional cyclobutane ligands (62 compounds), isolated from their photoproducts have been described and categorized according to their synthetic strategies. The utilization of those functional cyclobutane compounds as ligands for the construction of topological networks, either in the form of cocrystals or coordination polymers (CPs), is described. [ABSTRACT FROM AUTHOR]

An attempt has been made to design double-stranded ladder-like coordination polymers (CPs) of hemidirected PbII. Four CPs, [Pb(μ-bpe)(O2C-C6H5)2] ⋅2H2O ( 1), [Pb2(μ-bpe)2(μ-O2C-C6H5)2(O2C-C6H5)2] ( 2), [Pb2(μ-bpe)2(μ-O2C- p-Tol)2(O2C- p-Tol)2] ⋅ 1.5 H2O ( 3) and [Pb2(μ-bpe)2(μ-O2C- m-Tol)2(O2C- m-Tol)2] ( 4) (bpe=1,2-bis(4′-pyridyl)ethylene), have been synthesised and investigated for their solid-state photoreactivity. CPs 2- 4, having a parallel orientation of bpe molecules in their ladder structures and being bridged by carboxylates, were found to be photoreactive, whereas CP 1 is a linear one-dimensional (1D) CP with guest water molecules aggregating to form a hydrogen-bonded 1D structure. The linear strands of 1 were found to pair up upon eliminating lattice water molecules by heating, which led to the solid-state structural transformation of photostable linear 1D CP 1 into photoreactive ladder CP 2. In the construction of the double-stranded ladder-like structures, the parallel alignment of CC bonds in 2- 4 is dictated by the chelating and μ2-η2:η1 bridging modes of the benzoate and toluate ligands. The role of solvents in the formation of such double-stranded ladder-like structures has also been investigated. A single-crystal-to-single-crystal transformation occurred when 4 was irradiated under UV light to form [Pb2( rctt-tpcb)(μ-O2C- m-Tol)2(O2C- m-Tol)2] ( 5). [ABSTRACT FROM AUTHOR]

An attempt has been made to design double-stranded ladder-like coordination polymers (CPs) of hemidirected PbII. Four CPs, [Pb(μ-bpe)(O2C-C6H5)2] ⋅2H2O ( 1), [Pb2(μ-bpe)2(μ-O2C-C6H5)2(O2C-C6H5)2] ( 2), [Pb2(μ-bpe)2(μ-O2C- p-Tol)2(O2C- p-Tol)2] ⋅ 1.5 H2O ( 3) and [Pb2(μ-bpe)2(μ-O2C- m-Tol)2(O2C- m-Tol)2] ( 4) (bpe=1,2-bis(4′-pyridyl)ethylene), have been synthesised and investigated for their solid-state photoreactivity. CPs 2- 4, having a parallel orientation of bpe molecules in their ladder structures and being bridged by carboxylates, were found to be photoreactive, whereas CP 1 is a linear one-dimensional (1D) CP with guest water molecules aggregating to form a hydrogen-bonded 1D structure. The linear strands of 1 were found to pair up upon eliminating lattice water molecules by heating, which led to the solid-state structural transformation of photostable linear 1D CP 1 into photoreactive ladder CP 2. In the construction of the double-stranded ladder-like structures, the parallel alignment of CC bonds in 2- 4 is dictated by the chelating and μ2-η2:η1 bridging modes of the benzoate and toluate ligands. The role of solvents in the formation of such double-stranded ladder-like structures has also been investigated. A single-crystal-to-single-crystal transformation occurred when 4 was irradiated under UV light to form [Pb2( rctt-tpcb)(μ-O2C- m-Tol)2(O2C- m-Tol)2] ( 5). [ABSTRACT FROM AUTHOR]