Elevating the Performance of Heterometallic 3d/4f SMMs: The Role of Diamagnetic CoIII and ZnII Ions in Magnetization Dynamics.

Recent advances in the synthesis of 3d/4f Single-Molecule Magnets (SMMs) have revealed the effective role of incorporating diamagnetic CoIII or ZnII ions to enhance the magnetic properties of LnIII ions. This concept highlights notable examples of CoIII/LnIII and ZnII/LnIII SMMs documented in the recent literature, illustrating how the selection of various peripheral and/or bridging ligands can modulate the magnetic anisotropy of 4f metal ions, thereby increasing their energy barriers.

Quantum chemical computations and photophysical spectral features studies of two coumarin compounds.

An attempt was made to determine the ground state and excited state dipole moments and quantum chemical computations of two coumarin compounds, namely 3-hydroxy-3-[2-oxo-2-(2-oxo-2H-chromen-3-yl)-ethyl]-1,3-dihydro-indol-2-one (3HOCE) and 3-[2-(8-methoxy-2-oxo-2H-chromen-3-yl)-2-oxo-ethylidene]-1,3-dihydro-indol-2-one (3MOCE). Both compounds displayed a red shift with enhancement in solvent polarity. The larger excited state dipole moment indicated the more polar nature of the selected compounds in the excited state than in the ground state. Kinetic stability and chemical reactivity of the selected compounds were studied with help of the quantum chemical properties of the compounds such as frontier molecular orbital analysis using density functional theory calculations with B3LYP/6-311+G (d, p) basis sets. Molecular electrostatic potential, Mulliken charges, natural bond orbital, and nonlinear optical properties were further studied. NBO analysis showed proton transfer within the selected donor-acceptor, depicting the large energy of stabilization for the compounds. The calculated Fukui function inferred the local softness and electrophilicity indices of used solute compounds.

Data related to conformation dependence of tyrosine binding on the surface of graphene: Bent prefers over parallel orientation.

In this data article, M06-2X/6-31G(d) level optimized geometries of complexes of tyrosine conformers binding with graphene sheets are shown in top and side views with selected non-bonding distances. The images of frontier molecular orbitals from HOMO-15 to LUMO+15 of the complexes involving graphene with tyrosine conformers are presented and the isovalue is 0.003 au. For some complexes involving small graphene, the orbitals are from HOMO-5 to LUMO+5. The molecular orbitals highlighted with frames show obvious overlaps between the fragments. Total energies of small and large graphene (G S and G L ) and selected tyrosine conformers in gas and aqueous phases obtained at M06-2X/6-31G(d) level are given. The data also include total energies of all complexes in the gas phase and the aqueous phase, binding energies, BSSE (basis set superposition error) correction, and BSSE-corrected binding energies in gas phase and solvation effect on the binding energies obtained at M06-2X/6-31G(d) level. Mulliken charges of tyrosine conformers in gas and aqueous phases, and the deformation energy for tyrosine and graphene in the gas phase complexes are provided. The values of the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and HOMO-LUMO energy gaps for some of graphene-tyrosine complexes that were not reported in the article [1] are given. The data is related to the research article "Conformation dependence of tyrosine binding on the surface of graphene: Bent prefers over parallel orientation" [1].

DFT computations on: Crystal structure, vibrational studies and optical investigations of a luminescent self-assembled material.

The current work undertakes the growth and the physicochemical properties of a novel green-yellow luminescence semi-organic material, the 3-picolylammonium bromide abbreviated (Pico-Br). In this paper, we report the X-ray diffraction measurements which show that the crystal lattice consists of distinct 3-picolylammonium cations and free bromide anions connected via NH⋯Br and NH⋯N hydrogen bonds leading to form a two dimensional frameworks. Molecular geometry compared with its optimized counterpart shows that the quantum chemical calculations carried out with density functional method (DFT) well produce the perceived structure by X-ray resolution of the studied material. To provide further insight into the spectroscopic properties, additional characterization of this material have been performed with Raman and infrared studies at room temperature. Theoretical computations have been computed using the (DFT) method at B3LYP/LanL2DZ level of theory implemented within Gaussian 03 program to study the vibrational spectra of the investigated molecule in the ground state. Optical absorption spectrum inspected by UV-visible absorption reveals the appearance of sharp optical gap of 280nm (4.42eV) as well as a strong green photoluminescence emission at 550nm (2.25eV) is detected on the photoluminescence (PL) spectrum at room temperature. Using the TD/DFT method, HOMO-LUMO energy gap and the Mulliken atomic charges were calculated in order to get an insight into the material. Good agreement between the theoretical results and the experimental ones was predicted.

Experimental and density functional theory studies on benzalkonium ibuprofenate, a double active pharmaceutical ingredient.

Molecular aspects of a double active pharmaceutical ingredient in ionic liquid form, benzalkonium ibuprofenate (BaIb), were studied using density functional theory (DFT/B3LYP/6-31+G (d, p)). A detailed discussion on optimized geometry, energy, heat and the enthalpy of BaIb was carried out. The computed vibrational results agree well with the experimental results. The stability and biological activity were compared to the parent drugs on the basis of global descriptive parameters. The electrophilic and nucleophilic sites were pointed out in the MESP structures well evidently. NBO analysis was also done to predict the relative aromaticity, delocalization effects and the contribution towards stabilization energy of the title compound. The information about non-covalent, non-ionic weak interaction between the cation and anion was obtained from the list of Mulliken charges and NBO analysis.

Photodebromination behaviors of polybrominated diphenyl ethers in methanol/water systems: Mechanisms and predicting descriptors.

This study investigated the photodebromination behaviors of polybrominated diphenyl ethers (PBDEs) in methanol or methanol/water systems. The kinetics of three sets of bromated diphenyl ether (BDE) isomers were compared in the same reactors, and the results showed that the PBDE isomers with lower energy of lowest unoccupied molecular orbital and higher energy of highest occupied molecular orbital will be degraded faster by ultraviolet (UV) light than other BDE isomers. The overall debromination pathways of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) were elucidated, and we found that the bromine substituents with higher Mulliken charges were preferentially removed. This demonstrated that Mulliken charges can be used to predict the photodebromination pathways of PBDEs. In methanol/water systems, when the ratio of methanol and water decreased, the degradation rate of BDE-47 decreased, whereas that of diphenyl ether increased. This phenomenon can be attributed to the mechanism of photodegradation of PBDEs gradually shifting from the reductive debromination to the undebromination process as the ratio of methanol and water decreases. The chromatogram of high-performance liquid chromatography and gas chromatography-mass spectrometry during this process also verified this explanation. The debromination pathways of BDE-47 are consistent in methanol/water systems with different methanol to water ratios and in different organic solvents.

2H-[1,2,3]Triazolo[4,5-c]pyridine Cored Organic Dyes Achieving a High Efficiency: a Systematic Study of the Effect of Different Donors and π Spacers.

New D-A-π-A-based isomeric sensitizers, PTNn (n = 1-2) and NPTn (n = 1-5), were synthesized using 2H-[1,2,3]triazolo[4,5-c]pyridine (PT) as an auxiliary acceptor, triphenylamine or N,N-bis[4-(hexyloxy)phenyl]aniline as the donor, furan, thiophene, phenyl, or 3-hexylthiophene as the conjugated spacer, and 2-cyanoacrylic acid as the acceptor and anchor as well. They were used as the sensitizers of dye-sensitized solar cells. The NPTn dyes show better performance than the PTNn dyes. Among them, the best efficiency of 7.92% (∼96%, N719) was obtained with the NPT5 dye, indicating that the PT core could be used as a new building block for the design of high-performance sensitizers in the future. The negative Mulliken charge from the auxiliary acceptor was found to be useful as a semiempirical index for correlation of the molecular structure with the cell efficiency among structurally similar D-A-π-A-type congeners.

Surface enhanced Raman scattering, electronic spectrum, natural bond orbital, and Mulliken charge distribution in the normal modes of diethyldithiocarbamate copper (II) complex, [Cu(DDTC)2].

Surface-enhanced Raman scattering (SERS) was used to study the interactions of the normal modes of the diethyldithiocarbamate copper (II) complex, [Cu(DDTC)2] on nano-structured mixture silver-gold surfaces and on silver surfaces. The electronic spectrum of this complex was measured and the charge transfer bands were assigned through the TD-PBE1PBE procedure. Natural bond orbital (NBO) were also carried out to study the Cu(II) hybridation leading to the square planar geometry of the framework of the [Cu(DDTC)2] complex, and to study which are the donor NBO and the acceptor NBO in meaningful charge transfer through the Second Order Perturbation Theory Analysis of the Fox Matrix in NBO basis. To see the electronic dispersion, the Mulliken electronic charges (MAC) were calculated for each normal mode and correlated with the SERS effect. Full assignment of the SERS spectra was also supported by carefully analysis of the distorted geometries generated by the normal modes.