Tailoring the band-gap, optical and fluorescent properties of 3,5-diaminobenzoic acid via functionalization with chemical groups: A DFT study.

3,5-diaminobenzoic acid (3,5-DABA) with chemical formula C7H8N2O2 was functionalized with CH3-, OH-, NH2- and NO2- to obtain: CH3-3,5 DABA, OH-3,5 DABA, NH2-3,5DABA and NO2-3,5DABA. These molecules were built with Gauss view 6.0 and their structural, spectroscopic, optoelectronic and molecular properties were investigated using density functional theory (DFT). B3LYP (Becke's 3-parameter exchange functional with Lee-Yang-Parr correlation energy) functional and 6-311+ G (d, p) basis set were used to understand their reactivity, stability and optical activity. Integral equation formalism polarizable continuum model (IEF - PCM) was used to calculate the absorption wavelength, energy required to excite the molecules and oscillator strength. Our results reveal that the functionalization of 3,5 DABA with the groups caused a decrease of the energy gap from 0.1563 eV, to 0.1461 eV, 0.13818 eV and 0.13811 eV in NO2-3,5DABA, OH-3,5DABA and NH2-3,5DABA respectively. The lowest energy gap of 0.13811 eV for NH2-3,5DABA is in good agreement with its highest reactivity value (global softness of 7.240). The most observed significant donor - acceptor NBO interactions where found to occur between *ΠC16-O17 → *ΠC1-C2, *ΠC3-C4→ *ΠC1-C2, *ΠC1-C2 → *ΠC5-C6, *ΠC3-C4 → *ΠC5-C6, *ΠC2-C3 →*ΠC4-C5 natural bond orbitals having second- order stabilization energies of 101.95 kcal/mol, 368.41 kcal/mol, 174.51 kcal/mol, 255.63 kcal/mol and 235.92 kcal/mol in 3,5-DABA, CH3-3,5-DABA, OH-3,5-DABA, NH2-3,5-DABA and NO2-3,5-DABA respectively. The highest perturbation energy was observed in CH3-3,5DABA while the lowest perturbation energy was observed in 3,5DABA. The absorption band of the compounds were observed in the order: NH2-3,5DABA (404 nm) > N02-3,5DABA (393 nm) > OH-3,5DABA (386 nm) > 3,5DABA (349 nm) > CH3-3,5DABA (347 nm).

Synthesis, spectral characterization, and theoretical investigation of the photovoltaic properties of (E)-6-(4-(dimethylamino)phenyl)diazenyl)-2-octyl-benzoisoquinoline-1, 3-dione.

This research work focuses on the synthesis, characterization through spectra (FT-IR, UV-vis, and 1H-NMR) investigations, and the use of density functional theory (DFT) along with time-dependent density functional theory (TD-DFT) to investigate the electronic, structural, reactivity, photophysical properties, and the photovoltaic properties of a novel (E)-6-(4-(dimethylamino)phenyl)diazenyl)-2-octyl-benzoisoquinoline-1,3-dione. The structure of the synthesized compound was modeled using the Gaussian09W and GaussView6.0.16 softwares employing B3LYP and 6-31 + G(d) basis set. The DFT studies was performed in order to investigate the Frontier Molecular Orbital (FMO), Natural Bond Orbital (NBO), charge distribution, Nonlinear Optics (NLO), and stability of the titled molecule. The HOMO-LUMO energy gap which corresponds to the difference between HOMO and LUMO energies of the studied compound was found to be 2.806 eV indicating stiff and smooth nature of the titled molecule. This accounts for the less stability and high chemical reactivity of the compound. The photovoltaic properties were conducted to evaluate the light harvesting efficiency (LHE), short circuit current density (JSC), Gibbs free energy of injection ([Formula: see text]), open cycled voltage (VOC) and Gibbs free energy regeneration ([Formula: see text]) and solar cell conversion efficiency. Interestingly, the results obtained were found to be in good agreement with other experimental and computational findings.

Experimental and Density Functional Theory Studies on a Zinc(II) Coordination Polymer Constructed with 1,3,5-Benzenetricarboxylic Acid and the Derived Nanocomposites from Activated Carbon.

A coordination polymer with the composition C12H20O16Zn2 (ZnBTC) (BTC = benzene-1,3,5-tricarboxylate) was synthesized under hydrothermal conditions at 120 °C, and its crystal structure was determined using single-crystal X-ray crystallography. First-principles electronic structure investigation of the compound was carried out using the density functional theory computational approach. The highest occupied molecular orbital, the lowest unoccupied molecular orbital, the energy gap, and the global reactivity descriptors of ZnBTC were investigated in both the gas phase and the solvent phase using the implicit solvation model, while the donor-acceptor interactions were studied using natural bond orbital analyses. The results revealed that ZnBTC is more stable but less reactive in solvent medium. The larger stabilization energy E (2) indicates a greater interaction of ZnBTC in the solvent than in the gas phase. Orange peel activated carbon and banana peel activated carbon chemically treated with ZnCl2 and/or KOH were used to modify the synthesis of ZnBTC to obtain nanocomposites. ZnBTC and the nanocomposites were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis, and Fourier transform infrared. The specific surface area (S BET) and the average pore diameter of the materials were determined by nitrogen sorption measurements using the Brunauer-Emmett-Teller (BET) method, while scanning electron microscopy and transmission electron microscopy were used to observe their morphology and particle size, respectively. The PXRD of all the activated carbon materials exhibited peaks at 2θ values of 12.7 and 13.9° corresponding to a d-spacing of 6.94 and 6.32 Å, respectively. The N2 adsorption-desorption isotherm of the materials are of type II with nanocomposites showing enhanced S BET compared to the pristine ZnBTC. The results also revealed that activated carbons from the banana peel and the derived nanocomposites exhibited better porous structure parameters than those obtained from orange peel. The degradation efficiency of methyl orange in aqueous solutions using ZnBTC as a photocatalyst was found to be 52 %, while that of the nanocomposites were enhanced up to 79 %.

Hydrothermal synthesis and structural characterization of ammonium ion-templated lanthanide(III) carboxylate-phosphonates.

Using N-(phosphonomethyl) iminodiacetic acid (H4PMIDA), as a complexing agent, two new complexes, (NH4)La(PMIDA)(H2O)•H2O, 1 and (NH4)Yb(PMIDA), 2 have been synthesized hydrothermally. In both compounds, the metal ions are trapped by a three five-membered chelate rings by the chelating PMIDA anions giving a tricapped trigonal prismatic LaO8N and monocapped trigonal prismatic YbO6N geometries for 1 and 2, respectively. The structure of 1 consists of La(PMIDA)(H2O) chelating units, linked together by the phosphonate oxygen atoms O1 and O3 to form a chain along the c-axis. The chains are then connected together by the bridging phosphonate oxygen O2 to form a 2D layered structure with alternating 4- and 8-membered apertures. The structure of 2 consists Yb(PMIDA) chelating units, which are connected by alternating bridging carboxylate and phosphonate groups along the [010] direction forming chains with a corrugated pattern. The third phosphonate oxygen bridges the chains together along the [001] direction to build the two-dimensional layer with 4- and 6-membered apertures in the bc-plane. Under excitation of 330 nm, compound 2 shows a broad emission band at λmax = 460 nm. This emission is essentially in the blue luminescent region, which corresponds to ligand centered fluorescence.