Novel stereoselective molecularly imprinted polymers via ring-opening metathesis polymerisation

Stereoselective molecularly imprinted polymers (MIPs) have been synthesised via ring-opening metathesis polymerisation, in essentially, quantitative yield. A covalent imprinting strategy was followed during the network formation of the chiral sorbent. Recognition of the substrate however involved non-covalent interactions; a combination of hydrogen bonding and the chiral environment presented by the imprinted cavities. The enantiomeric excess achievable with these new MIPs is solvent dependent and stereoselectivities of up to 20% e.e. (separation factor α=2.2) were found in batch equilibrations.     

Nitrosyl rhenium complexes: Syntheses,properties, and structures of acetylacetonato derivatives

Some new complexes of rhenium containing monocoordinating acetylacetone viz. [Re(NO)(acac)₂(Cl)H₂O], Re(NO)(acac)₃(acacH)(H₂O)₂ have been synthesized by reacting acetylacetone with either Re(NO)Cl₃ · H₂O or Re(NO)(OH)₃ · H₂O. The preparation of [Re(NO)(py)(acac)₂(Cl) · H₂O], [Re(NO)(acac)(OH)(Cl) · H₂O], [Re₂(NO)₂(acacH)₃(acac)₂ · Cl₄], [Re(NO)(acac)₂(OH) · H₂O] · 2 H₂O have also been described. These complexes were characterized through their elemental analyses, u.v., vis, i.r., ¹Hn.m.r., magnetic, and conductance data.     

Synthetic analgesics: preparation of racemic 6,7-benzomorphans

A simple preparation of 2-carbomethoxy-2-azabicyclo[3.3.1]nonan-6-one ($\text{7}$ and its conversion to the racemic benzomorphans: $\text{9}$, $\text{10}$, $\text{14}$ are described.     

Extraction-photometric determination of vanadium(V) with N-hydroxy-N-m-tolyl-N′-(2-methyl-5-chloro)phenyl-p-toluamidine hydrochloride in the presence of acetic,monochloroacetic, and phenylacetic acids

N-Hydroxy-N-m-tolyl-N′-(2-methyl-5-chloro)phenyl-p-toluamidine hydrochloride (HTMCPTH), a monobasic and bidentate chelating agent which reacts with vanadium(V) in carboxylic acid media to develop a blue-violet complex, has been employed as a highly selective reagent for extraction and direct photometric determination of the metal. Solvent extraction experiments indicate that from aqueous acetic acid (1.0–10.0 M), monochloroacetic acid (0.1–10.0 M), and phenylacetic acid (at pH 0.5–6.0) vanadium(V) is quantitatively extracted into chloroform. Almost all common ions including Fe³⁺, Cu²⁺, Ni²⁺, Co²⁺, Mn²⁺, Cr³⁺, Ti⁴⁺, Zr⁴⁺, and Mo⁶⁺ do not interfere with the proposed method. The procedure has been utilized for accurate determination of vanadium in standard steels.     

σ,π-acetylido complexes via P---C bond cleavage of phosphinoacetylenes: X-ray structure of Fe2(CO)6(CCPh)(PPh2)

Solutions of Co^II salts of organic acids in primary amines absorb molecular oxygen rapidly and irreversibly forming μ-dioxygen—cobalt complexes. Thermolysis leads to a homopolar cleavage of the OO bond with subsequent radical reactions involving ligand amine. After thermolysis the capacity of oxygen uptake is reestablished (catalysis).     

Magnetic behaviour of spin-mixed iron(III) porphyrins

Detailed average magnetic susceptibility (295-4.2 K) and average magnetisation (20-2 K, 50-10 kOe) are reported for two novel spin-mixed iron(III) porphyrins, namely Fe(TPP)ClO4 and Fe(OEP)ClO4. The results confirm an S = 3/2 ground state substantially spin-mixed with a low-lying S = 5/2 state, but do not agree in detail with the crystal-field model of Maltempo.     

Thermal investigations on γ-radiation processed natural medicinal products (Ashwagandha,Amla and Hartiki)

DSC and TG studies were carried out on -radiation processed Indian natural products of medicinal importance, namely Ashwagandha (Withania Somnifera), Amla (Emblica Officinalis) and Hartiki (Terminalia chebula). DSC thermoanalytical curves were recorded from 35 to 400°C in air and nitrogen atmosphere. Similarly, TG thermoanalytical curves were taken from 35 to 700°C in air and nitrogen atmosphere. Irradiated products gave significantly different thermoanalytical profiles in comparison to non-irradiated samples. The differences were observed above decomposition temperature of 200°C and were non-linear with respect to radiation dose. Partial oxidation of the products during irradiation in air could be responsible for the observed differences.     

Recoil reactions of38Cl and128I in some heterocyclic systems

Halogen recoil following /n, / reaction has been studied in some heterocyclic systems. The organic yields are 60% for irradiation as solids: exceptions are dioxanide furoate /34%/ and 5-chloro isatoic anhydride /31%/. As solutions in 11 THF + benzene and 11 HTF+DMSO, these yields are lower by 10% and decrase further when only THF is the solvent. Mass-spectroscopy data revealed the possible fragmentation pattern.     

Studies on binuclear hydroxo/carboxylato-bridged manganese(III) complexes and a mononuclear manganese(III) complex involving salen type ligands

Synthesis of six hydroxo-bridged binuclear manganese(III) complexes of formulae [MnL-X-MnL](ClO₄) [X = OH (1–6)] along with a mononuclear manganese(III) complex (7) [Mn(L)(L′)(MeOH)₂] [HL′ = 2-(2-hydroxy-phen-yl)benzimidazole] and two carboxylate-bridged binuclear manganese(III) complexes (8) and (9) are described. The complexes have been characterized by the combination of i.r., u.v.-vis spectroscopy, magnetic moments and by their redox properties. The electronic spectra of all the complexes exhibit almost identical features consisting of two d–d bands at ca. 550 and 600 nm, one MLCT band at ca.400 nm, together with two π–π^* intra-ligand transitions at ca. 250 nm and ca.300 nm. Room temperature magnetic data range from μ = 2.7–3.0 BM indicates some super-exchange between the binuclear metal centers via bridging hydroxo/carboxylato groups. The X-ray crystal structure of the binuclear complex (5) revealed that it has a symmetric Mn^IIIN₂O₂ core bridged by a hydroxyl group. The X-ray analysis of the mononuclear complex (7) showed that the manganese-center possesses a distorted octahedral geometry. Electrochemical properties of hydroxo-bridged manganese(III) complexes (1–6) show identical features consisting of an irreversible and a quasi-reversible reduction corresponding to the Mn₂^III → Mn^IIMn^III → Mn^IIMn^II couples in the voltammogram. It was found that electron withdrawing substituents on the ligand result in easier reduction. Complex (7) displays an irreversible reduction at 0.08 V and a reversible oxidation at 0.45V assignable to the Mn^III → Mn^II reduction and Mn^III → Mn^IV oxidation, respectively. The carboxylate-bridged compound (8) exhibits two irreversible oxidations at 0.4 and 0.6 V, probably due to Mn₂^III → Mn^IIIMn^IV → Mn^IVMn^IV oxidations and shows a quasi-reversible reductive wave at −0.85 V, tentatively assigned to Mn₂^III → Mn^IIMn^III reduction.     

Role of hadronic dynamics in proton decay

Aspects of hadronic dynamics which play a crucial role in proton decay (exclusive and inclusive) are examined in the context of a comprehensive Bethe-Salpeter (BS) formalism forq \(\bar q\) andqqq systems, under harmonic confinement. The BS model which is characterized by two basic parameters—the universal spring constant \(\tilde \omega \) GeV and the quark massm _q =0.28 GeV, has already provided an impressive set of agreements in respect of a large number and variety of hadronic observables (mass spectra, and an extensive list of e.m. and pionic couplings of both mesons and baryons). TheSU(5) GUT parameters, on the other hand, are kept fixed at the ‘standard’ values, (see e.g. Langacker's review). The absolute normalization of the baryon, which is rather crucial in this case, is fixed with reference to the (topologically equivalent) process of its ‘dissociation’ into three quarks by a hard photon, which makes use of the structure function sum rule \(\int\limits_0^1 {dxF_2^p (x)/x = \sum {Q_i^2 } } \) , instead of the usual BS normalization (which amounts to the conservation of charge). Thee ⁺ inclusive rate, which is about three times that of thee ⁺π⁰ mode, works out at0.54×10 ^?33 yr ^?1 which is smaller than most contemporary calculations by two orders of magnitude. Other exclusive modes are also consistent with the above estimate. The theoretical implications of these results vis a vis contemporary calculations as well as current experimental searches are discussed.