Efficient Cu Decorated Inorganic B12P12 Nanoclusters for Sensing Toxic COCl2 Gas: A Detailed DFT Study

Gas sensing materials have been widely explored recently owing to their versatile environmental and agriculture monitoring applications. Phosgene (COCl2) is a toxic and harmful gas, therefore, a reliable and sensitive technique is required for monitoring its quantity in the atmosphere. In this study, pure as well as copper decorated B[Formula: see text]P[Formula: see text](Cu-BP) nanoclusters were analyzed using DFT method to investigate their specific potential for phosgene gas adsorption. Cu interaction resulted in three optimized geometries S1, S2 and S3 with interaction energies of [Formula: see text]234.52[Formula: see text]kJ/mol, [Formula: see text]214.59[Formula: see text]kJ/mol and [Formula: see text]266.45[Formula: see text]kJ/mol, respectively. In all these three cases, the COCl2 prefers to interact at the top of the cage. The phosgene molecule (COCl2) interacts with bare nanocage at a distance of 3.22[Formula: see text]Å with interaction energy of [Formula: see text]6.22[Formula: see text]kJ/mol, while the observed interaction energies of phosgene at Cu decorated B[Formula: see text]P[Formula: see text] are [Formula: see text]76.90[Formula: see text]kJ/mol, [Formula: see text]119.03[Formula: see text]kJ/mol and [Formula: see text]29.60[Formula: see text]kJ/mol, respectively. To observe the variations in electronic structure, fermi level, molecular electrostatic potential (MEP), frontier molecular orbitals (FMOs), natural bonding orbital ([Formula: see text]), softness, hardness, chemical potential and electrophilicity are calculated before and after phosgene adsorption. Energy gap reduce significantly after phosgene adsorption from 2.31[Formula: see text]eV, 2.05[Formula: see text]eV and 2.46[Formula: see text]eV to 1.54[Formula: see text]eV, 1.57[Formula: see text]eV and 2.45[Formula: see text]eV, respectively. Results of all analysis suggested that decoration of Cu significantly enhanced the adsorption power of B[Formula: see text]P[Formula: see text] nan-cluster for COCl2 molecule. Therefore, the Cu-decorated B[Formula: see text]P[Formula: see text] nanocages are considered as potential candidates for application in COCl2 sensors.

Quantum Chemical Computational Studies of Nitrogen Rich Energetic Organic Crystalline Salt: 2,4-Diamino-6-methyl-1,3,5-triazinium Trifluroacetate

An organic crystalline salt 2,4-diamino-6-methyl-1,3,5-triazinium trifluroacetate (DMTFA) has been imposed for experimental and theoretical investigation. Gaussian 09 program has been used to compute the quantum chemical theoretical calculations. DFT/B3LYP-6-311++G(d,p) approach is adapted to optimize the structure. Structural and vibrational studies have been carried out by this approach followed by the correlation of experimental and theoretical results. Natural bonding orbital analysis, molecular electrostatic potential and frontier molecular orbital investigations substantiates the charge transfer besides the presence of strong inter and intra molecular interactions. Apart from the three dimensional Hirshfeld surface analysis and two dimensional fingerprint maps provides profund vision about the intermolecular interactions between the molecules.

The structure of ortho-(trifluoromethyl)phenol in comparison to its homologues – A combined experimental and theoretical study

The molecular and crystal structure of commercially-availableortho-(trifluoromethyl)phenol were determined by means of single-crystal X-ray diffractometry (XRD) and represent the first structural characterization of anortho-substituted (trihalomethyl) phenol. The unexpected presence of a defined hydrate in the solid state was observed.Intermolecular contacts and hydrogen bonding were analyzed. The compound was further characterized by means of multi-nuclear nuclear magnetic resonance (NMR) spectroscopy (1H,13C{1H},19F) and Fourier-Transform infrared (FT-IR) vibrational spectroscopy. To assess the bonding situation as well as potential reaction sites for reactions with nucleophiles and electrophiles in the compound by means of natural bonding orbital (NBO) analyses, and density functional theory (DFT) calculations were performed for the title compound as well as its homologous chlorine, bromine and iodine compounds. As far as possible, experimental data were correlated to DFT data.

The [4 + 4] thermocyclization of 9-anthraldehyde: synthesis, crystal structure, experimental and theoretical UV spectra, natural bonding orbital analysis and prediction of third-order nonlinear optical properties

The dimer of 9-anthraldehyde, namely heptacyclo[8.6.6.62,9.03,8.011,16.017,22.023,28]octacosa-3,5,7,11,13,15,17(22),18,20,23(28),24,26-dodecaene-1,9-carbaldehyde, C30H20O2, has been synthesized by refluxing an ethanol solution in the presence of M(ClO4)2 and 1,3-diaminopropan-2-ol (M = Co2+ or Cu2+). Its structure has been determined by single-crystal X-ray diffraction, showing it to be a new polymorph, referred to as polymorph II, in the monoclinic space group P21/n. It is compared with the previously reported triclinic modification [Ehrenberg (1968). Acta Cryst. B24, 1123–1125], which is referred to as polymorph I. The asymmetric unit of polymorph II contains two half molecules located on crystallographic centres, while the asymmetric unit of polymorph I includes one half molecule, also located on a crystallographic centre. Time-dependent density functional theory (TD-DFT) at the RB3LYP level using the 6-31G(d,p) basis set was applied. The predicted electronic absorption spectrum is in good agreement with the experimental one. The analysis of the calculated electronic absorption spectrum of polymorph II was carried out in order to assign the observed electronic transitions and to determine their character. A natural bonding orbital (NBO) analysis was executed at the same level to evaluate charge-transfer, intramolecular hydrogen-bonding interactions and hyperconjugative interactions. The third-order nonlinear optical (NLO) properties of the compound were appraised by the ZINDO/sum-over-states method in both static and dynamic states. The orientationally averaged (isotropic) value of γ for the compound is greater than the corresponding value of 4-nitroaniline (pNA).

Combined experimental and theoretical studies on molecular structures, spectroscopy of 4-(3-(2-amino-3,5-dibromophenyl)-1-(benzoyl)-4,5-dihydro-1H-pyrazol-5-yl)benzonitriles through NBO, FT-IR, HOMO-LUMO and NLO analyzes

The pyrazole compounds 4-(3-(2-amino-3,5-dibromophenyl)-1-(4-substitutedbenzoyl)-4,5-dihydro-1H-pyrazol-5-yl) benzonitriles (4–6) have been synthesized and characterized by elemental, IR, 1HNMR spectral methods. In addition, the synthesized compounds were subjected to density functional theory for further understanding of the molecular architecture and optoelectronic properties. The optimized geometric parameters were in support of the corresponding experimental values. The FT-IR spectra of 4–6 have been investigated extensively using DFT employing B3LYP/6-31G (d,p) level theory. The molecular electrostatic potential analysis has been utilized to identify reactive sites of title compounds. Natural bonding orbital analysis proved the inter- and intra-molecular delocalization and acceptor–donor interactions based on the second-order perturbation interactions. The calculated band gap energies revealed that charge transfer occurs within the molecule. The polarizability and hyperpolarizability were calculated which show that compounds posses nonlinear optical nature.

Effects of the Electronegativity of Second Row Elements on Their Bonding to Boron

The effects of electronegativity on the bonding between boron and second row elements are studied in this paper. Calculations using Density Functional Theory (DFT), Moller-Plesset Theory (MP2) and Natural Bonding Orbital (NBO) analysis were performed on BF3, B(OH)3 and B(NH2)3 and the localized bonding properties of these molecules were elucidated. All of these molecules showed the absence of pi-bonding and did not obey the octet rule. With decreasing electronegativity of the terminal atoms, F, O and N in BF3, B(OH)3, B(NH2)3 there is increasing the propensity of electron donation from these terminal atoms to the empty p-orbital of the central boron. Within the BH2−F, BH2−OH and BH2−NH2 series, the amino-borane showed the largest change in relative bond length and angle across this set. Furthermore, the borate anion, −O−B(OH) 2 was subjected to identical analysis and pi-bond formation was observed. Our results show that a good match orbital energies between the donor and acceptor orbitals are important for pi-bond formation. KEYWORDS: Electronegativity; Boron Trifluoride; Boric Acid; Triaminoborane; Borate Anion; Octet Rule; Density Functional Theory; Natural Bonding Orbital; Pi-Bond; Double Bond

Characterizations of Novel Binuclear Transition Metal Polynitrogen Compounds: M2(N5)4 (M=Co, Rh and Ir)

Theoretical studies on a series of binuclear transition metal pentazolides M2(N5)4(M=Co, Rh and Ir) predict Paddlewheel-type structures with very short metal-metal distances suggesting high-order metal-metal multiple bonds. Natural Bonding Orbital (NBO) analysis have indicated that the bonding between the metal atom and the five-membered ring is predominantly ionic for each M2(N5)4species, and a high-order metal-metal multiple bonding exists between the two metal atoms, in addition, the presence of the delocalized π orbital plays an important role in the stabilization of this metal-polynitrogen species. Nucleus independent chemical shift (NICS) values confirm that the planar N5exhibits aromaticity in these M2(N5)4species. The values of NICS(0.0), NICS(0.5) and NICS(1.0) for Co2(N5)4are larger than those of the other two M2(N5)4species (M=Rh and Ir), with the order of Co2(N5)4>Rh2(N5)4>Ir2(N5)4. The dissociation energies into Mononuclear Fragments for M2(N5)4(M=Co, Rh and Ir) are predicted to be 82.9 (85.7), 139.9 (113.2), and 155.1 (149.7) kcal/mol, respectively. However, the dissociation energies for the loss of one pentazolato group from the M2(N5)4analysis have indicated that the Co2(N5)4is relatively higher at ~40 kcal/mol. Thermochemistry suggests Co2(N5)4to be a viable species.