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In this article, we present the syntheses, crystal structures, vibrational spectra, optical and antibacterial properties of two new organic-inorganic hybrids, [Py(CH2)3TPP][CoCl4]·H2O (1) and [Py(CH2)3TPP][CuCl4] (2), where [Py(CH2)3TPP]2+ was 1-(1′-pyridyl-propyl)-3-triphenyl phosphonium. Two hybrids were crystallized in the monoclinic space group P21/n. The hybrids consisted of a [Py(CH2)3TPP]2+ cation and a tetrahedral [CoCl4]2−/[CuCl4]2− anion, where the crystal structure was stabilized by C−H···Cl, O−H···Cl, and C−H···O hydrogen bonds due to the presence of a water molecule in 1, and the crystal structure of 2 was stabilized by C−H···Cl hydrogen bonds. Experimental vibrational bands (IR and Raman) have been discussed and assigned. The intermolecular energy, the energy gap between HOMO and LUMO orbitals, as well as the first hyperpolarizabilities were predicted based on DFT calculations. The low energy gaps (1.26 eV for 1 and 1.20 eV for 2) were responsible for the charge transfer interactions that eventually occur between the cation and anion. The first hyperpolarizabilities (βtot) of 1 and 2 were 82 and 237 times as high as that of the standard KDP crystal, respectively, indicating that the as-prepared hybrids were excellent materials for NLO applications. Furthermore, it was found that both salts exhibit good bactericidal activity against Escherichia coli and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Co-crystal materials formed by stacking different molecules with weak interactions are a hot research topic. In this work, we theoretically investigate the intermolecular interactions and charge transfer properties of the supramolecular BDBT-TCNB co-crystal (BTC). The π-π bonds, hydrogen bonds, and S-N bonds in the BTC bind the BDBT and TCNB molecules together to form a highly ordered co-crystal and lead to the co-crystal's excellent two-photon absorption (TPA) properties. The intermolecular interactions of the BTC are discussed in detail by the independent gradient model based on Hirshfeld partition (IGMH), atoms in molecules (AIM), electrostatic overlay diagram, and symmetry-adapted perturbation theory (SAPT) energy decomposition; it is found that there is a strong interaction force along the stacking direction. The charge transfer properties of the one-photon absorption (OPA) and TPA of the BTC were investigated by charge density difference (CDD) and transition density matrix (TDM). It is found that the dominant charge transfer mode is the cross-space charge transfer along the stacking direction. Therefore, strong intermolecular interactions will promote intermolecular cross-space charge transfer. This work is of great significance for the design of organic optoelectronic supramolecular materials. [ABSTRACT FROM AUTHOR]

A new organic hybrid material, 2,4-dichlorobenzyl triphenylphosphinium picrate, [2Cl4ClBzTPP][PIC](1), has been grown by slow evaporation solution growth technique, and characterized by elemental analysis, spectroscopy, thermal analysis, powder and single crystal XRD. The composite belongs to monoclinic system with space group P 2(1)/ c , and consists of a pair of [2Cl4ClBzTPP]+ cations and picrate anions. The experimental vibrational bands (IR and Raman) have been discussed and assigned based on DFT calculations. The HOMO-LUMO energy gap explains the charge transfer interactions in the molecule. TG-TDA technique reveals that the title crystal was stable up to 168 °C. The fluorescence spectra reveal that the compound shows violet and green fluorescence emissions at 377 and 509 nm upon excitation at 250 nm in solid state at room temperature. The energy of weak interactions in the molecule and nonlinear optical properties were studied using DFT calculations. Image 1 • A organic crystal of substituted benzyl triphenylphosphinium picrate salt was synthesized and characterized. • The experimental vibrational bands (IR and Raman) have been discussed and assigned based on DFT calculations. • The HOMO-LUMO energy gap explains the charge transfer interactions in the molecule. • The energy of weak interactions in the molecule and nonlinear optical properties were studies using DFT calculations. • The title crystal show violet and green fluorescence emissions at 377 and 509 nm in solid state at room temperature. [ABSTRACT FROM AUTHOR]