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A systematic one-step one-pot multicomponent reaction of Co(ClO4)(2)center dot 6H(2)O, H3L (2,6-bis((2-(2-hydroxyethylamino)ethylimino)methyl)-4-methylphenol), and readily available carboxylate salts (RCO2Na; R = CH3, C2H5) resulted in the two structurally novel coordination aggregates [(CoCo4L2)-Co-II-L-III(mu(1,3)-O2CCH3)(2)(mu-OH)(2)](ClO4)(4)(center dot) 4H(2)O(1) and [Co(II)co(4)(III)L(2)(mu(1,3)-O2CC2H5)(2)(mu-OH)(mu-OMe)](ClO4)(4)center dot 5H(2)O (2). At room temperature, reactions of H3L in MeOH with cobalt(II) perchlorate salts led to coassembly of initially formed ligand-bound {Co-2(II)} fragments following aerial oxidation of metal centers and bridging by in situ generated hydroxido/alkoxido groups and added carboxylate anions. Available alkoxido arms of the initially formed {L(mu(1,3)-O2CCH3)(mu-OH/OMe)Co-2}(+) fragments were utilized to trap a central Co-II ion during the formation of [Co-5] aggregates. In the solid state, both complexes have been characterized by X-ray crystallography, variable-temperature magnetic measurements, and theoretical studies. Both 1 and 2 show field-induced slow magnetic relaxation that arises from the single pseudo-T-d Co-II ion present. The structural distortion leads to an easy-axis magnetic anisotropy (D = -31.31 cm(-1) for 1 and -21.88 cm(-)1 for 2) and a small but non-negligible transverse component (E/D = 0.11 for 1 and 0.08 for 2). The theoretical studies also reveal how the O-Co-O bond angles and the interplanar angles control D and E values in 1 and 2. The presence of two diamagnetic {Co-2(mu-L)} hosts controls the distortion of the central {CoO4} unit, highlighting a strategy to control single-ion magnetic anisotropy by trapping single ions within a diamagnetic coordination environment.

Solvothermal synthesis of a highly porous metal-organic framework (PMOF) of Cu(II) had been achieved with a bent tetracarboxylate linker, L4- incorporating an -NH2 group in the middle. The design of the linker afforded paddle-wheel secondary building unit (SBU) with metal bound solvent molecules. Upon activation by heating, the overall integrity of the structure remained intact with the result of a PMOF embellished with unsaturated metal centers (UMCs) and free -NH2 groups. This activated PMOF showed adsorption of 6.6% by weight of H-2 gas at 77 K and 62 bar and very high 60% by weight of CO2 gas at 298 K and 32 bar. The adsorption/desorption properties of this MOF has been probed theoretically to obtain additional insights into physisorption of these strategically important gases. The binding energy values reveal the willingness of the CO2 and H-2 gas molecules to get absorbed in Cu(II)-MOF. Temperature-pressure (T-P) phase diagrams have been generated for both of the gas absorption processes at omega B97x-D/TZVP level of theory. Temperature and pressure regions have been identified where Gibbs free energy is negative that is the absorption process is spontaneous. The ab initio molecular dynamics study reveals that the gas saturated Cu(II)-MOFs are stable. Thus this Cu(II)-MOF can be used as an effective gas storage material. (C) 2018 Elsevier Ltd. All rights reserved.

A cost-effective equation of motion coupled cluster method, EOMIP-CCSD(2), is used to investigate vertical and adiabatic ionization potential as well as ionization-induced structural changes of water clusters and compared with CCSD(T), CASPT2, and MP2 methods. The moderate N(5) scaling and low storage requirement yields EOMIP-CCSD(2) calculation feasible even for reasonably large molecules and clusters with accuracy comparable to CCSD(T) method at much cheaper computational cost. Our calculations shed light on the authenticity of EOMIP-CCSD(2) results and establish a reliable method to study of ionization energy of molecular clusters. We have further investigated the performance of several classes of DFT functionals for ionization energies of water clusters to benchmark the results and to get a reliable functionals for the same.

International audience; The natural product epicocconone, owing to its unique fluorescence properties, has been developed into a range of products used in biotechnology, especially proteomics. However, its weak green fluorescence in its native state, while advantageous for proteomics applications, is a disadvantage in other applications that require two-color readouts. Here we report the photophysical characterization of two brightly fluorescent analogues of epicocconone. These analogues, with naphthyl or pyridyl groups replacing the heptatriene chain, resulted in bright fluorescence in both the native state and the long Stokes shifted enamine. Time-resolved fluorescence studies and DFT calculations were carried out to understand the excited state processes involved in fluorescence. Results showed the p-chloro group on the pyridyl is responsible for the high fluorescence of the native fluorophore. The application of one of these compounds for staining electrophoresis gels is exemplified.

Synthesis, thermodynamic characterization, and energetic properties of three novel high-nitrogen bishomocubane-based compounds DADMBHC, DTetzBHC and DPTrizDMBHC are reported here. These compounds have higher heats of formation (HoFs) and higher energy densities as compared to traditional hydrocarbon fuels. Densities, gas phase HoF and their optimized molecular structure geometries were calculated with various levels of theory. In general, the calculated HoFs of these compounds turn out to be extremely high. Ballistic properties such as vacuum specific impulse and density vacuum specific impulse were calculated using the NASA Chemical Equilibrium and Applications utility. Propulsive properties were compared with liquid bipropellants (RP1) and solid propellants (AP) and explosive properties were compared with RDX. The density specific impulse demonstrated an improvement of 35 s for DADMBHC and DTetzBHC over standard liquid hydrocarbon HTPB, thus showing promise as possible monomers to replace HTPB as a fuel-binder. The density specific impulses of these compounds were also found to be significantly higher than that of RP1, e.g. that of DADMBHC was found to be higher by 84 s, making them potentially good candidates as propellants for use under volume-limited conditions. The detonation properties showed that these compounds have low potential as explosives. TGA, coupled with IR spectroscopy, revealed that DADMBHC and DPTrizDMBHC evaporate readily while DTetzBHC decomposes partially. publishedVersion