Computational study on non-linear optical property of Wittig based Schiff-Base ligands (both Z & E isomers) & Copper(II) complex

Transition metalides based on facially polarized all-cis-1,2,3,4,5,6-hexafluorocyclohexane - a new class of high performance second order nonlinear optical materials

Continuous attempts are being made to discover new approaches to design materials with extraordinary nonlinear optical responses. Herein, for the first time, we report the geometric, electronic, and nonlinear optical properties of novel Janus transition metalides AM-J-TM (where AM = Li, Na and K, and TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) containing alkali metals as a source of excess electrons for transition metals to generate metalides. The Janus organic complexant used for the study is all cis 1,2,3,4,5,6-hexafluorocyclohexane F₆C₆H₆ (J). These complexes contain the unique involvement of alkali metals (AM = Li, Na and K) as a source of excess electrons, which significantly affects the hyperpolarizability values of the resulting transition metalides. The NBO analysis reveals the charge transfer from alkali metals to the transition metals, thereby confirming the metalide behavior of the complexes. Moreover, the metalide nature of these complexes is validated through frontier molecular orbital (FMO) analysis. The values of interaction energies, vertical ionization potential (VIP) and vertical electron affinity (VEA) illustrate the stability of the metalide complexes. Ultimately, the hyperpolarizability values confirm the excellent nonlinear optical response of the designed transition metalides. The remarkable static first hyperpolarizability (β₀) response up to 4 × 10⁸ a.u. is observed for complexes of vanadium. Similarly, the complexes of AM-J-Mn and Li/Na-J-Sc show significantly high NLO response. These compounds besides providing a new entry into excess electron compounds will also pave the way for the design and synthesis of further novel NLO materials.

Two state "ON-OFF" NLO switch based on coordination complexes of iron and cobalt containing isomeric ligand: a DFT study

Coordination complexes are interesting materials for nonlinear optical (NLO) applications due to their large hyperpolarizability values. Moreover, switchable NLO response is also important in coordination complexes. Herein, we report two state ON-OFF switchable NLO contrast of coordination complexes of Fe and Co containing isomeric ligands. The optical, UV-visible, and electronic properties besides the "ON-OFF" switching effect are calculated using the CAM-B3LYP/6-31+G (d) method. The NLO responses of ligand-metal isomers are qualitatively evaluated through variation in charge transference (CT) style through TD-DFT. The higher β o in each isomeric pair is strongly dependent on the HOMO-LUMO gap. The isomer 4b with lowest HOMO-LUMO gap shows the highest NLO response. The charge transfer pattern in these complexes results in variation of their β o values. The notable β o contrast of 21.15 in isomeric pairs 3a and 3b makes these complexes a favorable material for genuine NLO switches. Hence, the outcome of the current investigation reveals that these ligand-metal isomeric complexes exhibit a two-state switch "ON-OFF" effect.

Structural and theoretical study of copper(ii) complex incorporating chalcone and 2,2′-bipyridine mixed ligands: a probable candidate for optical material

We report the synthesis, structural and photophysical data for a Cu(ii) complex, [Cu(L·bpy)(NO3)], with mixed chalcone and 2,2′-bipyridine ligands. Calculations are used to consider prospective applications in optoelectronic devices.

Spectral, NBO, NLO, NCI, aromaticity and charge transfer analyses of anthracene-9,10-dicarboxaldehyde by DFT

Anthracene-9,10-dicarboxaldehyde (ADCA) is a polynuclear aromatic compound that has a planar structure with double bonds which are in conjugation. The molecule is subjected to theoretical investigation with DFT/B3LYP/6-311++G(d,p) basis set to find out the electronic structural properties and stability. Theoretical and experimental vibrational analyses are carried out. NBO studies predict that the molecule has high stability. NCI interaction studies reveal that Van der Waals force and steric effect are seen in the molecule. A shaded surface map with a projection of LOL analysis pointed out that electron depletion area is seen in this molecule. The tunnelling current is more in the boundary rings than the central ring. It is docked with the protein 4COF and the binding energy is found to be -6.6 kcal/mol. Electrons excitation analysis is performed and found that local excitation takes place for the lowest five excitations. The aromaticity of the molecule is also thoroughly investigated.

Second-order NLO properties and two-state switching effects of transition metal redox complexes of iron and cobalt: A DFT study

Designing switchable materials with large contrasts of nonlinear optical properties has been the focus of research in recent decades because of their widespread applications. Redox-active metal complexes due to charge transfer excitation are suitable to produce switchable nonlinear optical (NLO) material. In this regard, we present here the redox switchable NLO response of active metal complexes of iron and cobalt. The geometric, electronic, molecular absorption, nonlinear optical properties, and switch "ON/OFF" style of these metal complexes are studied at the CAM-B3LYP/6-31 + G(d) level of theory. NLO responses of these redox metal complexes are described in terms of change in the charge transfer (CT) patterns by time dependent density functional theory (TD-DFT). The highest β_o value of 301534 × 10^-30 esu is noticed in [Fe-ethynyl-ZnP]¹⁺ complex, because of obvious charge transfer transition from metal to ligand i.e meatal-ligand charge transfer (MLCT) in redox metal complex. In each redox metal isomeric pair, the greater hyperpolarizability value of individual isomer is quite consistent with its smaller energy gap (H-Lgap) between highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO), low crucial excitation energy, and bathochromic shift of λ_max. The remarkable β_o contrasts of these isomeric redox complexes illustrate that they can be appropriate for effective redox-triggered NLO switches. Thus, the results reveal that these redox pair complexes show two-state switching "ON/OFF" effect.

Design, docking, and DFT investigations of 2,6-bis(3,4-dihydroxyphenyl)-3-phenethylpiperidin-4-one

In the present investigation, a totally of 673 newly designed 2,6-diphenyl piperidin-4-one derivatives are docked with 2B7N protein of Helicobacter pylori which causes peptic ulcer disease. The docking studies revealed that 2,6-bis(3,4-dihydroxyphenyl)-3-phenethylpiperidin-4-one (BDPO) is identified as the most promising new compound with active nature against 2B7N with a binding affinity value of -8.0 Kcal/mol. The molecular structure of BDPO has been analyzed by DFT based theoretical calculations at the B3LYP/6-311++G(d,p) level of theory using the Gaussian 16W program package. The molecular electrostatic potential, Frontier molecular energy gap, and Mulliken population analysis have been used to understand the reactive site of the molecule. The stability and hyper-conjugative interactions were studied by natural bond orbital analysis (NBO) based on a second-order perturbation approach. The thermodynamic properties like thermal energy, specific heat capacity, and entropy at different temperatures were also calculated. The calculated first-order hyper polarizability results show that the title compound is 25.3 times greater than that of standard reference material, urea. So the title molecule is a good non-linear material. Also, this molecule has Van der Waals attraction and steric effect. It undergoes local excitation for the first five excitations.