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41.
Jayalakshmi Gopal M. Srinivasan 《Journal of polymer science. Part A, Polymer chemistry》1986,24(7):1577-1583
Polybenzoxazinones were synthesized by solution polycondensation from five different aromatic diacidchlorides and 3,3′-diaminoazobenzene-4,4′-dicarboxylic acid through a polyamic acid precursor which was further cyclodehydrated to polybenzoxazinones. The amic acid and the benzoxazinones were obtained in 85–93% and 56–63% yield, respectively. The polymers were characterized by physical and thermal analysis. 相似文献
42.
R. Rajagopal S. A. Siddiqui Thomas Daniel R. J. Lahoti K. V. Srinivasan 《Journal of molecular catalysis. A, Chemical》2004,210(1-2):165-169
Regioselective monobromination of aromatic substrates with N-bromosuccinimide has been achieved in excellent isolated yields (84–98%) using phosphotungstic acid supported on zirconia as a novel heterogeneous catalyst. The catalyst has been characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), surface area and acidity measurements. Remarkably, the new catalyst system described brought about the side-chain bromination of aromatics to afford bromomethyl arenes in excellent yields (86–98%) without the need for a radical initiator. Recovery and recylability of the catalyst have been well established. 相似文献
43.
44.
Parmeswaran D Pushpan SK Srinivasan A Ravi Kumar M Chandrashekar TK Ganesan S 《Photochemistry and photobiology》2003,78(5):487-495
The core modification of expanded porphyrins has been proved to have better photochemical properties, which are favorable for photodynamic therapy (PDT) applications. In this context, this study was aimed to investigate the in vitro and in vivo photodynamic activity of one such core-modified expanded porphyrin, namely, ammonium salt of 5,10,15,20-tetrakis-(meso-p-sulfonato phenyl)-25,27,29-trithia sapphyrin. For the in vitro studies, human erythrocytes were used as a membrane semimodel system to investigate the partitioning ability and drug-uptake characteristics. The partition studies on the membrane semimodel system revealed that maximum partitioning occurs at 12 microgm/mL concentration, and from the drug-uptake studies it is observed that maximum amount of the sensitizer is bound to the erythrocyte membranes during a 45 min incubation period. Photohemolysis studies at different concentrations of the sensitizer and exposure time showed maximum damage at 5 microgm/mL and 30 min exposure time. In vivo studies were performed on 7,12-dimethylbenz(a)nthracene-induced superficial squamous cell carcinoma on mouse skin. The sensitizer at a concentration of 2.5% in 2.0% dimethyl sulfoxide was applied topically on the tumor spot. After 1 h incubation the tumor spot was exposed to laser irradiation from Nd-YAG laser at its second harmonic wavelength of 532 nm. The photodynamic efficacy was estimated by tumor volume measurements at regular intervals after the treatment. One month after PDT exposure a 3.9-fold decrease in the tumor volume was observed with respect to the tumor volume before treatment. The treatment efficacy was further confirmed by histological and fluorescence spectroscopic evaluations of the tissue biopsy sample from the treated area. The results of our study suggest that the ammonium salt of 5,10,15,20-tetrakis-(meso-p-sulfonato phenyl)-25,27,29-trithia sapphyrin may find possible applications in the new modality of cancer treatment. 相似文献
45.
The kinetics of the oxidation of methyl phenyl sulfoxide (MPSO) by potassium peroxodiphosphate (PP) in 50% aqueous acetic acid obeys the rate law.-d[PP]T/dt=k[PP] [MPSO] at constant [H+]. The active species in the oxidation has been found to be H3P2O
8
–
. The kinetic results have been explained by a polar mechanism.
() () 50%- (./.) -d[]T/dt=k·[]·[] [H*]. H3P2O 8 – . .相似文献
46.
A hydrothermal reaction of a mixture of ZnCO3, phosphoric acid, 1, 10‐phenanthroline in H2O gave rise to large plates of a new zinc phosphate, [(C12H8N2Zn)2(HPO4)(H2PO4)2], I . The structure consists of ZnO3N2 distorted trigonal‐bipyramidal and PO4 tetrahedral units linked through their vertices to give rise to a zero‐dimensional molecular solid (monomer). The structure of the monomer appears to be similar to the secondary building unit (SBU) 4 = 1, commonly found in many fibrous zeolites. To our knowledge, this is the first time this building unit has been isolated. The structure, with a unique composition, is stabilized by hydrogen bond interactions between the terminal —OH groups forms a one‐dimensional molecular wire and also by strong π…π interactions between the 1, 10‐phenanthroline units. Photoluminescence studies show that there is a ligand‐to‐metal charge transfer (LMCT). Crystal data: orthorhombic, space group = Fdd2 (no. 43), a = 40.4669(1), b = 7.4733(2), c = 17.4425(5)Å, V = 5274.9(2)Å3, Z = 8. 相似文献
47.
Bikshandarkoil R. Srinivasan Christian N?ther Sunder N. Dhuri Wolfgang Bensch 《Monatshefte für Chemie / Chemical Monthly》2006,121(2):397-411
Four new organic ammonium tetrathiotungstates (N–Me–enH2)[WS4] (1), (N,N′-dm-1,3-pnH2)[WS4] (2), (1,4-bnH2)[WS4] (3), and (mipaH)2[WS4] (4), (N–Me–enH2 = N-methylethylenediammonium, N,N′-dm-1,3-pnH2 = N,N′-dimethyl-1,3-propanediammonium, 1,4-bnH2 = 1,4-butanediammonium, and mipaH = monoisopropylammonium) were synthesized by the base promoted cation exchange reaction and characterized by elemental analysis,
infrared, Raman, UV-Vis and 1H NMR spectroscopy as well as single crystal X-ray crystallography. The structures of 1–4 consist of [WS4]2− tetrahedra which are linked to the organic ammonium cations via N–H⋯S hydrogen bonding. The strength and number of the S⋯H
interactions affect the W–S bond lengths as evidenced by distinct short and long W–S bonds. The IR spectra exhibit splitting
of the W–S vibrations, which can be attributed to the distortion of the [WS4]2− tetrahedron. From a comparative study of several known tetrathiotungstates it is observed that a difference of more than
0.033 ? between the longest and shortest W–S bonds in a tetrathiotungstate will result in the splitting of the asymmetric
stretching vibration of the W–S bond. 相似文献
48.
Two polymorphs of zero-dimensional zinc phosphate with the formula, 0∞[Zn(2,2′-bipy)(H2PO4)2], have been synthesized employing hydrothermal technique and their structure determined by single crystal X-ray diffraction. Both the structures consists of ZnO3N2 distorted trigonal-bipyramidal and PO2(OH)2 tetrahedral units linked through their vertices giving rise to a zero-dimensional molecular zinc phosphate. The structures are stabilized by extensive hydrogen bond interactions between zero-dimensional monomers. The structures display subtle differences in their packing created by hydrogen bond interactions. Crystal data: polymorph I, triclinic, space group (No. 2), , , , α=67.32(3)°, β=81.67(3)°, γ=69.29(3)°, , Z=2; polymorph II, triclinic, space group (No. 2), , , , α=97.37(2)°, β=100.54(2)°, γ=100.98(2)°, , Z=2. 相似文献
49.
Bikshandarkoil R. Srinivasan Christian Näther Sunder N. Dhuri Wolfgang Bensch 《Monatshefte für Chemie / Chemical Monthly》2006,137(4):397-411
Summary. Four new organic ammonium tetrathiotungstates (N–Me–enH2)[WS4] (1), (N,N′-dm-1,3-pnH2)[WS4] (2), (1,4-bnH2)[WS4] (3), and (mipaH)2[WS4] (4), (N–Me–enH2 = N-methylethylenediammonium, N,N′-dm-1,3-pnH2 = N,N′-dimethyl-1,3-propanediammonium, 1,4-bnH2 = 1,4-butanediammonium, and mipaH = monoisopropylammonium) were synthesized by the base promoted cation exchange reaction and characterized by elemental analysis,
infrared, Raman, UV-Vis and 1H NMR spectroscopy as well as single crystal X-ray crystallography. The structures of 1–4 consist of [WS4]2− tetrahedra which are linked to the organic ammonium cations via N–H⋯S hydrogen bonding. The strength and number of the S⋯H
interactions affect the W–S bond lengths as evidenced by distinct short and long W–S bonds. The IR spectra exhibit splitting
of the W–S vibrations, which can be attributed to the distortion of the [WS4]2− tetrahedron. From a comparative study of several known tetrathiotungstates it is observed that a difference of more than
0.033 ? between the longest and shortest W–S bonds in a tetrathiotungstate will result in the splitting of the asymmetric
stretching vibration of the W–S bond. 相似文献
50.