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The hydrogen bonding of the complexes formed between formic acid and water molecules (with up two water) has been completely investigated in the present study using density functional theory (DFT) and secondorder Moller-Plesset perturbation (MP2) method; the large basis sets 6-311++g(d,p) and 6-311++g(2d,2p) have been employed to determine the equilibrium structure and vibrational frequencies of the interacting complexes. Twelve reasonable geometries on the potential energy hypersurface of the formic acid and water system are considered; six are with one water molecule, and six are with two water molecules. For the complexes with one water molecule, three are with the (T)-formic acid and three are with (C)-formic acid, and the most stable structure is a cyclic double-hydrogen-bonded structure. For the complexes with two water molecules, we calculated six structures, the global minimum being a cyclic double-hydrogen-bonded structure. The optimized geometric parameters and interaction energies for various isomers at different levels are estimated. The infrared spectrum frequencies, IR intensities, and vibrational frequency shifts are reported. Finally the solution phase studies are also carried out using the Onsager reaction field model in water solvent at B3LYP/6-311++g(d,p) level.

ABSTRACT:The hydrogen bonding complexes formed between the H 2 O and OH radical have been completely investigated for the first time in this study using density functional theory (DFT). A larger basis set 6-311ϩϩG(2d,2p) has been employed in conjunction with a hybrid density functional method, namely, UB3LYP/6-311ϩϩG(2d,2p). The two degenerate components of the OH radical 2 ⌸ ground electronic state give rise to independent states upon interaction with the water molecule, with hydrogen bonding occurring between the oxygen atom of H 2 O and the hydrogen atom of the OH radical. Another hydrogen bond occurs between one of the H atoms of H 2 O and the O atom of the OH radical. The extensive calculation reveals that there is still more hydrogen bonding form found first in this investigation, in which two or three hydrogen bonds occur at the same time. The optimized geometry parameter and interaction energy for various isomers at the present level of theory was estimated. The infrared (IR) spectrum frequencies, IR intensities, and vibrational frequency shifts are reported. The estimates of the H 2 O ⅐ OH complex's vibrational modes and predicted IR spectra for these structures are also made. It should be noted that a total of 10 stationary points have been confirmed to be genuine minima and transition states on the potential energy hypersurface of the H 2 O ⅐ HO system. Among them, four genuine minima were located.

Fiber-shaped Zn-ion batteries with TiN@V2O5 as cathode have excellent electrochemical performance.

The proton-transfer mechanism in the isolated, mono, dehydrated forms and dimers of 2-pyridone and the effect of hydration or self-assistance on the transition state structures corresponding to proton transfer from the keto form to the enol form have been investigated using B3LYP and BH-LYP hybrid density functional methods at the 6-311++G (2d, 2p) basis set level. The barrier heights for both H2O-assisted and self-assisted reactions are significantly lower than that of the bare tautomerization reaction from 2-pyridone to 2-hydroxypyridine, implying the importance of the superior catalytic effect of H2O and (H2O)2 and the important role of 2-pyridone itself for the intramolecular proton transfer. Long-range solvent effects have also been taken into account by using the continuum model (Onsager model and polarizable continuum model (PCM)) of water. The tautomerization energies and the potential energy barriers are increased both for the water-assisted and for the self-assisted reaction because of the bulk solvent, which imply that the tautomerization of PY becomes less favorable in the polar solvent.

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The microRNA miR396 directly represses GROWTH-REGULATING FACTORs (OsGRFs) and has been implicated in regulating rice yield and in nitrogen assimilation. Overexpressing the miR396 targets OsGRF4 and OsGRF6 improves rice yield via increased grain size and panicle branching, respectively. Here, we used CRISPR/Cas9 to assess the function of miR396 genes in rice. Knockout of MIR396ef (MIR396e and MIR396f), but not other isoforms, enhanced both grain size and panicle branching, resulting in increased grain yield. Importantly, under nitrogen-deficient conditions, mir396ef mutants showed an even higher relative increase in grain yield as well as elevated above-ground biomass. Furthermore, we identified OsGRF8 as a new target of miR396, in addition to the known targets OsGRF4 and OsGRF6. Disruption of the miR396-targeting site in OsGRF8 was sufficient to both enlarge grain size and elongate panicles. Our results suggest that rice-seed and panicle development are regulated by miR396ef-GRF4/6/8-GIF1/2/3 modules and that miR396ef are promising targets of genome editing for breeding environmentally friendly rice varieties that require less nitrogen fertilization.

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