Quantum Chemical Vibrational Study,FTIR and FT-Raman Spectra of 1,3-Diphenyl Propenone

The Fourier Transform Infrared (FTIR) and Fourier transform Raman (FT-Raman) spectra of 1,3-Diphenyl Propenone were recorded in the regions 4 000～400 and 4 000～100 cm-1, respectively, in the solid phase. Molecular electronic energy, geometrical structure, harmonic vibrational spectra was computed at the DFT/ 6-31G(d,p) and three parameter hybrid functional Lee-Yang-Parr/6-31G(d,p) levels of theory. The vibrational studies were interpreted in terms of potential energy distribution (PED). The results were compared with experimental values with the help of scaling procedures. Most of the modes have wave numbers in the expected range and are in good agreement with computed values and also the molecular properties of Mulliken population analysis have been calculated. Besides, thermodynamic properties were performed.     

Zinc(II)‐N2O2 ligation complex‐based DNA/protein binder and cleaver having enhanced cytotoxic and phosphatase activity

The alkyne arms containing zinc(II) N₂O₂ ligation complexes ( 1 ) and ( 2 ) were prepared from 2,2′‐{cyclohexane‐1,2‐diylbis[nitrilo(E)methylylidene]}bis[5‐(prop‐2‐yn‐1‐yloxy)phenol] (L¹) and 2,2′‐{1,2‐phenylenebis[nitrilo(E)methylylidene]}bis[5‐(prop‐2‐yn‐1‐yloxy)phenol] (L²) and characterized by analytical and various spectral techniques. The molecular geometry of 1 and 2 was optimized by Density Functional Theory (DFT) at B3LYP/6‐311G(d,p) level and compared with literature. The complexes are stable in solution, and their solution structure was assessed using NMR and ESI‐MS spectroscopy. Topological analysis of the electron density and nature of the bonding in the complexes has been determined by using Bader's AIM method. The interaction and binding modes of calf thymus DNA (CT‐DNA) with complexes ( 1 and 2 ) were investigated by using absorption and emission spectral and viscometric studies. The nuclease activity investigated through gel electrophoresis reveals that 1 and 2 exhibits a significant DNA cleavage activity via a hydrolytic pathway and is further confirmed by an experiment performed in the presence of T4 ligase. The protein binding ability of 1 and 2 with bovine serum albumin (BSA) protein evaluated show good protein binding propensity. In‐vitro cytotoxicity of the complexes has shown significant activity against human brain tumor (U87 MG) and breast carcinoma (BT20) cancer cell lines. The comet assay has been used to determine the extent of DNA fragmentation in cancer cells. The phosphatase activity investigated through kinetic measurements establishes that the zinc complexes possess significant hydrolytic efficiency and follow the order 2  >  1 . The DFT calculations have also been carried out to support the proposed mechanistic pathway of catalytic activity.     

Electrocatalytic cyclization of dithiothreitol on a chemically modified electrode by analogy with protein action

Electrocatalytic oxidative cyclization of dithiothreitol (DTT(SH)2) to a disulfide product was demonstrated on a Nafion/lead-ruthenium oxide pyrochlore chemically modified electrode (NPyCME). The process at the NPyCME with DTT(SH)2 is similar to the behaviour of protein in a disulfide linkage, which can be demonstrated by product analysis using HPLC coupled with UV spectroscopy. A possible electrocatalytic mechanism for DTT(SH)2 oxidation to dihydroxydithiane [i.e. cyclized DTT(S-S)] on the NPyCME was proposed in terms of Py-Ru(IV)/Py-Ru(VI) redox active sites. This physical aspect was further utilized for high precision analytical assays using flow injection analysis (FIA), with a linearity up to 50 microM and a detection limit (S/N = 3) of 28 nM (8.64 pg) in a 20 microL sample loop. This is the most sensitive method ever reported for DTT(SH)2 detection assays. The interference from dissolved oxygen, disulfide and glucose is almost negligible. The present method offers an easy route for extension to redox-related protein studies.     

Electrochemical performance of SnO2 hexagonal nanoplates

This study reports the electrochemical performance of SnO₂ hexagonal nanoplates (SnO₂-NPs) coated on copper substrate by electrodeposition method in different aqueous electrolytes. The influence of deposition voltage on the morphology of the nanoplates was investigated by scanning electron microscopy. The synthesized SnO₂ was characterized using SEM, X-ray diffraction, Raman, FTIR and UV–visible absorption spectrum. The results clearly have shown that with the increase in deposition voltage at constant deposition time, the thickness of the plate decreased. The obtained nanoplates were of several hundred nanometers in planar dimension and about 50-300 nm in thickness. The electrochemical reaction of SnO₂-NPs with lithium ions were investigated by cyclic voltammetry in LiOH·H₂O, Li₂CO₃, LiNO₃ and Li₂SO₄ aqueous solution. The SnO₂ hexagonal nanoplates deposited on copper substrate can be an ideal anode material for aqueous rechargeable lithium-ion battery.     

Low-valent vanadium complexes of a pyrrolide-based ligand. Electronic structure of a dimeric V(I) complex with a short and weak metal-metal bond

Deprotonation of the nitrogen atoms of the two pyrrole rings of 1,3-bis-{[(1'-pyrrol-2-yl)-1,1'-dimethyl]methyl}benzene with KH followed by further reaction with either VCl 3(THF) 3 or with VCl 2(TMEDA) 2 respectively gave the paramagnetic complexes [1,3-bis-{[(1'-pyrrol-2-yl)-1,1'-dimethyl]methyl}benzene]VCl(DME) ( 1) and [1,3-bis-{[(1'-pyrrol-2-yl)-1,1'-dimethyl]methyl}benzene]V(THF) 3 ( 2). Further reduction with the appropriate amount of KH afforded diamagnetic dinuclear [1,3-bis-{[(1'-pyrrol-2-yl)-1,1'-dimethyl]methyl}benzene]V} 2] ( 3). In complex 3, the bridging interaction between the two metal centers is realized via the ligand central benzene ring. Density functional theory calculations have elucidated the nature of the electronic interaction between the two metals with the bridging pi-system thus accounting for its visible structural distortion. Calculations also pointed out the presence of only a weak V-V bond in spite of the short V-V distance.     

A one pot synthesis of annulated carbazole analogs

A ZnBr₂-mediated arylation of N-protected 2/3-bromomethylindoles containing an electron-deficient malonylidene unit with arenes at 80 °C led to the formation of arylated products, which on unprecedented 1,5-sigmatropic rearrangement followed by electrocyclization and subsequent aromatization with loss of diethylmalonate furnished the corresponding annulated carbazoles in reasonable yields.     

Molybdenum Incorporated Strontium-Iron and Strontium-Cobalt (SrBMoO3−δ; B=Fe & Co) Perovskites: Preparation and Their Application on Oxidation of Iso-Eugenol into Vanillin

SrBO_3−δ (B=Fe & Co) type perovskite oxides and their 25 % molybdenum doped counterparts, SrFe_0.75Mo_0.25O_3−δ (SFMO) and SrCo_0.75Mo_0.25O_3−δ (SFCO) are synthesized by the conventional solid-state method and systematically characterized using Fourier transfer infrared spectroscopy, powder X-ray diffraction, thermo-gravimetric analysis, nitrogen sorption, and temperature-programmed reduction. The powder X-ray diffraction patterns and FTIR spectral analysis evident the formation of the pure cubic phase and the doping of molybdenum into the perovskite crystal lattice. The variable oxidation states of iron and cobalt and the formation of oxygen vacancies are apparent from the TPR-H₂ and TGA curves, respectively. All of the samples have a lower surface area than porous materials, which is typical of the bulk oxide character. The iron-based perovskite demonstrated superior activity to the cobalt-based one for the oxidation of iso-eugenol to 4-hydroxy-3-methoxybenzaldehyde (vanillin) when employing aqueous H₂O₂ as the oxidant. The maximum conversion of 73 % with 63 % selectivity for vanillin was obtained within 1.5 h at 60 °C over the SFMO catalyst. The catalytic conversion was almost similar upon re-use of the catalyst.     

Self-supported chiral titanium cluster (SCTC) as a robust catalyst for the asymmetric cyanation of imines under batch and continuous flow at room temperature

A robust heterogeneous self-supported chiral titanium cluster (SCTC) catalyst and its application in the enantioselective imine-cyanation/Strecker reaction is described under batch and continuous processes. One of the major hurdles in the asymmetric Strecker reaction is the lack of availability of efficient and reusable heterogeneous catalysts that work at room temperature. We exploited the readily hydrolyzable nature of titanium alkoxide to synthesize a self-supported chiral titanium cluster (SCTC) catalyst by the controlled hydrolysis of a preformed chiral titanium-alkoxide complex. The isolated SCTC catalysts were remarkably stable and showed up to 98 % enantioselectivity (ee) with complete conversion of the imine within 2 h for a wide variety of imines at room temperature. The heterogeneous catalysts were recyclable more than 10 times without any loss in activity or selectivity. The robustness, high performance, and recyclability of the catalyst enabled it to be used in a packed-bed reactor to carry out the cyanation under continuous flow. Up to 97 % ee and quantitative conversion with a throughput of 45 mg h(-1) were achieved under optimized flow conditions at room temperature in the case of benzhydryl imine. Furthermore, a three-component Strecker reaction was performed under continuous flow by using the corresponding aldehydes and amines instead of the preformed imines. A good product distribution was obtained for the formation of amino nitriles with ee values of up to 98 %. Synthetically useful ee values were also obtained for challenging α-branched aliphatic aldehyde by using the three-component continuous Strecker reaction.     

On the perturbation of the H-bonding interaction in ethylene glycol clusters upon hydration

Ab initio and density functional methods have been employed to study the structure, stability, and spectral properties of various ethylene glycol (EG(m)) and ethylene glycol-water (EG(m)W(n)) (m = 1-3, n = 1-4) clusters. The effective fragment potential (EFP) approach was used to explore various possible EG(m)W(n) clusters. Calculated interaction energies of EG(m)W(n) clusters confirm that the hydrogen-bonding interaction between EG molecules is perturbed by the presence of water molecules and vice versa. Further, energy decomposition analysis shows that both electrostatic and polarization interactions predominantly contribute to the stability of these clusters. It was found from the same analysis that ethylene glycol-water interaction is predominant over the ethylene glycol-ethylene glycol and water-water interactions. Overall, the results clearly illustrate that the presence of water disrupts the ethylene glycol-ethylene glycol hydrogen bonds.