Titanium(IV) nonmetallocene complex catalyzed aqueous homopolymerization and copolymerization of styrene and methyl methacrylate: An Environmentally friendly approach to ultrahigh molecular weight polymer nanoparticles

A new titanium(IV) complex bearing [ONO] type ligand has been synthesized, characterized, and employed as catalyst in homopolymerization and copolymerization of styrene and methyl methacrylate. In the presence of sodium tetraphenyl borate and sodium n‐dodecyl sulfate (SDS), it exhibits moderate to high activity and afford ultrahigh molecular weight polymers. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Laser Raman studies on compounds 7.O4O.7 and 7.O5O.7

Laser Raman studies on two compounds of the α,ω-bis(4-alkylanilinebenzylidene -4′-oxy)alkane series were carried out in the spectral regions 1140–1220 and 1550–1650 cm^-1 as a function of temperature. Compounds 7.O4O.7 and 7.O5O.7, exhibit SmA and SmF phases. The structural differences between these liquid crystal dimers, having either an odd or an even number of carbon atoms in the spacer, are remarkably existent in the room temperature Raman spectra. The results are rationalized on the basis of the tendency of these compounds to exhibit bent shapes, and how this manifests in the odd-even effect at the molecular level assuming a semi-rigid core region of the dimeric molecule. It is found that the behaviour of the odd spacer dimer (7.O5O.7) agrees with the molecular model, whereas the even spacer dimer (7.O4O.7) behaves in a similar fashion to monomeric compounds such as the nO.m. compounds. In both cases, dynamic changes around the C=N bond have a profound effect both on the molecular shape in the different phases and on phase behaviour.     

In Vitro Renaturation of Alkaline Family G/11 Xylanase via a Folding Intermediate: α-Crystallin Facilitates Refolding in an ATP-Independent Manner

In this study, alkaliphilic family G/11 xylanase from alkali-tolerant filamentous fungi Penicillium citrinum MTCC 6489 was used as a model system to gain insight into the molecular aspects of unfolding/refolding of alkaliphilic glycosyl hydrolase protein family. The intrinsic protein fluorescence suggested a putative intermediate state of protein in presence of 2 M guanidium hydrochloride (GdmCl) with an emission maximum of 353 nm. Here we studied the refolding of GdmCl-denatured alkaline xylanase in the presence and the absence of a multimeric chaperone protein α-crystallin to elucidate the molecular mechanism of intramolecular interactions of the alkaliphilic xylanase protein that dictates its extremophilic character. Our results, based on intrinsic tryptophan fluorescence and hydrophobic fluorophore 8-anilino-1- naphthalene sulfonate-binding studies, suggest that α-crystallin formed a complex with a putative molten globule-like intermediate in the refolding pathway of xylanase in an ATP-independent manner. A 2 M GdmCl is sufficient to denature alkaline xylanase completely. The hydrodynamic radius (R_H) of a native alkaline xylanase is 4.0, which becomes 5.0 in the presence of 2 M GdmCl whereas in presence of the higher concentration of GdmCl R_H value was shifted to 100, indicating the aggregation of denatured xylanase. The α-crystallin·xylanase complex exhibited the recovery of functional activity with the extent of ~43%. Addition of ATP to the complex did not show any significant effect on activity recovery of the denatured protein.     

Determination of cobalt ions at nano-level based on newly synthesized pendant armed macrocycle by polymeric membrane and coated graphite electrode

Poly(vinylchloride) (PVC) based membranes of macrocycles 2,3,4:9,10,11-dipyridine-1,3,5,8,10,12-hexaazacyclotetradeca-2,9-diene (L₁) and 2,3,4:9,10,11-dipyridine-1,5,8,12-tetramethylacrylate-1,3,5,8,10,12-hexaazacyclotetradeca-2,9-diene (L₂) with NaTPB and KTpClPB as anion excluders and dibutylphthalate (DBP), benzyl acetate (BA), dioctylphthalate (DOP), o-nitrophenyloctyl ether (o-NPOE) and tri-n-butylphosphate (TBP) as plasticizing solvent mediators were prepared and investigated as Co²⁺ selective electrodes. The best performance was observed with the membranes having the composition L₂:PVC:TBP:NaTPB in the ratio of 6:39:53:2 (w/w; mg). The performance of the membrane based on L₂ was compared with polymeric membrane electrode (PME) and coated graphite electrode (CGE). The PME exhibits detection limit of 4.7 × 10⁻⁸ M with a Nernstian slope of 29.7 mV decade⁻¹ of activity between pH 2.5 and 8.5 whereas CGE exhibits the detection limit of 6.8 × 10⁻⁹ M with a Nernstian slope of 29.5 mV decade⁻¹ of activity between pH 2.0 and 9.0. The response time for PME and CGE was found to be 11 and 8 s, respectively. The CGE has been found to work satisfactorily in partially non-aqueous media up to 35% (v/v) content of methanol, ethanol and 25% (v/v) content of acetonitrile and could be used for a period of 4 months. The CGE was successfully applied for the determination of Co²⁺ in real and pharmaceutical samples and as an indicator electrode in potentiometric titration of cobalt ion.     

Rigid extensions of algebraic frames

An extension G ≤ H of lattice-ordered groups is said to be a rigid extension if for each ${h \in H}An extension G ≤ H of lattice-ordered groups is said to be a rigid extension if for each h ? H{h \in H} there exists a g ? G{g \in G} such that h ^⊥⊥ = g ^⊥⊥. In this paper, we will define rigid extensions and some other generalizations in the context of algebraic frames satisfying the FIP. One of the main results is a characterization of rigid extensions using d-elements of the frame. We also show that a rigid extension between two algebraic frames satisfying the FIP will induce a homeomorphism between their corresponding minimal prime spaces with respect to both the hull-kernel topology and the inverse topology. Moreover, basic open sets map to basic open sets.     

Oxovanadium (IV) complexes of bidentate [N,O] donor Schiff-base ligands: synthesis and mesomorphism

A series of new oxovanadium(IV) Schiff-base complexes of the type [VO(L)₂], [L?=?N-(4-n-alkoxysalicylaldimine)-4′-dodecyloxyaniline, n?=?6, 8, 16, and 18] have been synthesized. The compounds were characterized by FT-IR, ¹H-NMR, ¹³C-NMR, UV-Vis, FAB-mass, and magnetic susceptibility measurements. The mesomorphic behavior of the compounds was studied by polarized optical microscopy and differential scanning calorimetry. The compounds are all highly thermally stable exhibiting smectic mesomorphism. Non-electrolytic nature of the complexes was ascertained by solution electrical conductance measurements. Cyclic voltammetry revealed a quasireversible single-electron response for VO(V)/VO(IV) couple. A ν_V=O stretching mode at ～970?cm^?1 indicates absence of any intermolecular V=O?···?V=O interactions. Density functional theory study was carried out using DMol3 at BLYP/DNP level to determine energy optimized structure revealed a distorted square pyramidal geometry for the vanadyl complexes.     

Vibrational spectra of H2O and CF4 molecules using Lie algebraic approach

In this paper, we introduce one dimensional vibron model to analyze the fundamental, overtone and combination modes of CF₄ molecule and both stretching, bending vibrational mode of bent H₂O molecule up to first overtone with few algebraic parameters. Using the model Hamiltonian, we reported here better results for the vibrational spectra of H₂O. Our analysis suggests some reassignments of levels and predicts location of states in case of CF₄ molecule which was not yet observed.     

Lamron ℓ-groups

The article introduces a new class of lattice-ordered groups. An ?-group G is lamron if Min(G)^?1 is a Hausdorff topological space, where Min(G)^?1 is the space of all minimal prime subgroups of G endowed with the inverse topology. It will be evident that lamron ?-groups are related to ?-groups with stranded primes. In particular, it is shown that for a W-object (G,u), if every value of u contains a unique minimal prime subgroup, then G is a lamron ?-group; such a W-object will be said to have W-stranded primes. A diverse set of examples will be provided in order to distinguish between the notions of lamron, stranded primes, W-stranded primes, complemented, and weakly complemented ?-groups.