Page 83 - Book of Abstracts
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th
                               8  Biannual Conference on Chemistry - CHEM 08


                       Electronic Structure, UV-Spectra and NLO Analysis of 5-[(4-Oxo-4H-
                        chromen-3-yl) methylidene]-4-oxo(thioxo)-6-thioxo-2-sulfido-1,3,2-
                                            diazaphosphinanes:TD-DFT
                                     Shimaa Abdel Halim  * and Tarik E. Ali     2
                                                             1
                     1 Department of Chemistry, Faculty of Education, Ain Shams University,
                     Roxy, Cairo, Egypt,  Department of Chemistry, Faculty of Science, King
                                          2
                                      Khalid University, Abha, Saudi Arabia
                                     Email: shimaabdelhalim@edu.asu.edu.eg

                                                     ABSTRACT

                    The spectra of UV-Vis of 1,3,2-diazaphosphinines 1-4 were measured in
                    different solvents polar and non-polar. Quantum mechanical calculations
                    using DFT/B3LYB/6-311G (d,p) at level of theory  were predict the
                    optimized  geometry and dipole moment of these compounds   in the
                    ground state theoretically predicted using. The results of calculations
                    showed that the presence of phosphorus and sulfur atoms changed the
                    planarity of the parent compound 1 by the range from -11  to 125  . TD-
                                                                                   °
                                                                                            °
                    DFT/B3LYP/6-311G(d,p) computations for compounds 1-4 to predict the
                    spectra of electronic absorption in methanol and dioxane utilizing a PCM.
                    The effect of solvents and substitutions on the electronic absorption
                    spectra of these compounds  was investigated. The presence of
                    phosphorus and sulfur atoms had significant effects on both band maxima
                    and band intensity.  The absorption bands observed for compounds 1-
                    3 undergo blue shift, while compound 4 showed red shift. The theoretical
                    spectra of compounds computed at CAM-B3LYP/6-311G (d,p) in gas
                    phase, methanol and dioxane reproduce those experimentally observed.
                    The natural bond orbital (NBO)  analysis and second order perturbation
                    interactions between donor and acceptor MOs of the ground state showed
                    a localization and  delocalization of electron density as well as
                    intermolecular  charge  transfer  CT  character  of  π-π*  transitions.  The
                    calculated at the same level of theory which NLO, α, Δα and first order β
                    were showed promising optical properties. The compounds have 3D-plots
                    of the molecular electrostatic potential (MEP) were analyzed to describe

                    the distribution of electronic density of orbital's which describing the
                    active sites of the molecules.
                    Keywords: UV-Vis spectra, TD-DFT, NBO and NLO analysis, 1,2,3-
                    diazaphosphinanes, chromone.





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