01682nas a2200157 4500008004100000022001400041245015400055210006900209260011000278300001600388490000700404520095400411100001601365700001701381856012601398 2013 eng d a1463-907600aExploring the effectiveness of different Lewis pair combinations in caged structures for the catalysis of ammonia borane dehydrogenation: a DFT study0 aExploring the effectiveness of different Lewis pair combinations aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a20857-208670 v153 a

Zero dimensional cage structures containing four phenyl rings separated by imine linkers have recently been synthesized. In the current work, through a computational investigation using density functional theory (DFT), we demonstrate that modifying such cages by replacing the 2, 4, 6 carbon atoms in the phenyl rings to yield new rings, as well as replacing the imine moiety in the linker by other electronegative atoms, can yield interesting new cages that can be reactive in catalysing reactions such as the dehydrogenation of ammonia borane-an important reaction in hydrogen storage research. Specifically, it is predicted that phosphorus-nitrogen pairs (phosphorus in the 2, 4, 6 positions in the ring, nitrogen in the linker position), germanium-nitrogen and germanium-phosphorus pair combinations would lead to effective Lewis pairs that can work in tandem to dehydrogenate ammonia borane efficiently under room temperature conditions.

1 aPal, Amrita1 aVanka, Kumar uhttps://library.ncl.res.in/content/exploring-effectiveness-different-lewis-pair-combinations-caged-structures-catalysis-004003nas a2200349 4500008004100000022001400041245018200055210006900237260000800306490000700314520273100321653003003052653002203082653003003104653002703134653001203161653003003173653004903203653003703252653001703289100002303306700002003329700001803349700002003367700002303387700002403410700003103434700001603465700002503481700001703506856013003523 2017 eng d a1477-922600aExploring the effect of hydroxylic and non-hydroxylic solvents on the reaction of [(VO)-O-IV(beta-diketonate)2] with 2-aminobenzoyl-hydrazide in aerobic and anaerobic conditions0 aExploring the effect of hydroxylic and nonhydroxylic solvents on cSEP0 v463 a

Refluxing [(VO)-O-IV(beta-diketonate)(2)], namely [(VO)-O-IV(acetylacetonate)(2)] and [(VO)-O-IV(benzoylacetonate)(2)], separately with an equivalent or excess amount of 2-aminobenzoylhydrazide (ah) in laboratory grade (LG) CH3OH in aerobic conditions afforded non-oxidovanadium(IV) and oxidovanadium(V) complexes of the type [V-IV(L-1)(2)] (1), [(VO)-O-V(L-1)(OCH3)](2) (3) and [V-IV(L-2)(2)] (2), and [(VO)-O-V(L-2)(OCH3)] (4), respectively. (L-1)(2-) and (L-2)(2-) represent the dianionic forms of 2-aminobenzoylhydrazone of acetylacetone (H2L1) and benzoylacetone (H2L2), respectively, (general abbreviation, H2L), which was formed by the in situ condensation of ah with the respective coordinated [beta-diketonate] in medium-to-good yield. The yield of different resulting products was dependent upon the ratio of ah to [(VO)-O-IV(beta-diketonate)(2)]. For example, the yield of 1 and 2 complexes increased significantly associated with a decrease in the amount of 3 and 4 with an increase in the molar ratio of ah. Upon replacing CH3OH by a non-hydroxylic solvent, LG CHCl3, the above reaction yielded only oxidovanadium(V) complexes of the type [(VO)-O-V(L-1)(OH)](2) (5), [(VO)-O-V(L-2)(OH)] (6) and [(V2O3)-O-V(L)(2)] (7, 8) whereas, upon replacing CHCl3 by another non-hydroxylic solvent, namely LG CH3CN, only the respective [(V2O3)-O-V(L)(2)] (7, 8) complex was isolated in 72-78% yield. However, upon performing the above reactions in the absence of air using dry CH3OH or dry CHCl3, only the respective [V-IV(L)(2)] complex was obtained, suggesting that aerial oxygen was the oxidising agent and the type of pentavalent product formed was dependent upon the nature of solvent used. Complexes 3 and 4 were converted, respectively, to 7 and 8 on refluxing in LG CHCl3 via the respective unstable complex 5 and 6. The DFT calculated change in internal energy (Delta E) for the reactions 2[(VO)-O-V(L-2)(OCH3)] + 2H(2)O -> 2[(VO)-O-V(L-2)(OH)] + 2CH(3)OH and 2[(VO)-O-V (L-2)(OH)] -> [(V2O3)-O-V(L-2)(2)] + H2O was, respectively, +3.61 and -7.42 kcal mol(-1), suggesting that the [(VO)-O-V(L-2) (OH)] species was unstable and readily transformed to the stable [(V2O3)-O-V(L-2)(2)] complex. Upon one-electron reduction at an appropriate potential, each of 7 and 8 generated mixed-valence [(L) (VO)-O-V-(mu-O)-OVIV(L)]species, which showed valence-delocalisation at room temperature and localisation at 77 K. Some of the complexes showed a wide range of toxicity in a dose-dependent manner against lung cancer cells comparable with that observed with cis-platin.

10aEffective Core Potentials10aLung-cancer cells10aMolecular-Orbital Methods10aNon-oxido vanadium(iv)10aNon-Oxo10aOxovanadium(iv) Complexes10aTridentate ono ligand; Ray crystal-structure10aTrigonal-prismatic Co-ordination10aV-IV complex1 aBiswas, Nirmalendu1 aPatra, Debashis1 aMondal, Bipul1 aBera, Sachinath1 aAcharyya, Swarnali1 aBiswas, Anup, Kumar1 aMukhopadhyay, Titas, Kumar1 aPal, Amrita1 aDrew, Michael, G. B.1 aGhosh, Tapas uhttps://library.ncl.res.in/content/exploring-effect-hydroxylic-and-non-hydroxylic-solvents-reaction-vo-o-ivbeta-diketonate2-2