(2E)-1-(5-Chlorothiophen-2-yl)-3-(2,3-dimethoxyphenyl)prop-2-en-1-one

In the title compound, C(15)H(13)ClO(3)S, the chlorothiophene and dimethoxyphenyl groups are linked by a prop-2-en-1-one group. The C=C double bond exhibits an E conformation. The molecule is non-planar, with a dihedral angle of 31.12 (5)degrees between the chlorothiophene and dimethoxyphenyl rings. The methoxy group at position 3 is coplanar with the benzene ring to which it is attached, with a C-O-C-C torsion angle of -3.8 (3)degrees. The methoxy group attached at position 2 of the benzene ring is in a (+)synclinal conformation, as indicated by the C-O-C-C torsion angle of -73.6 (2)degrees. In the crystal, two different C-H center dot center dot center dot O intermolecular interactions generate chains of molecules extending along the b axis.

Efficacies of multivalent vs monovalent poly(ether imine) dendritic catalysts within a generation in multiple C-C bond forming reactions

Dendrimers are ideal platforms to study multivalent effects due to the presence of uniform end groups at their peripheries. This report concerns with a study of multivalent dendritic catalysts, both within and across dendrimer generations, and their effects to mediate C-C bond forming reactions on multivalent substrates that have two and three acrylate reactive sites. As many as fourteen multivalent dendritic catalysts were prepared using 0-3 generations of poly(propyl ether imine) dendrimers, incorporated with Pd(II) catalytic sites, both within and across the dendrimer generations. C-C Bond forming reactions of these substrates with iodobenzene, mediated by uniform concentration of the metal across all catalysts, showed formation of partially and fully functionalized cinnamates in varying ratios, depending on the extent of clustering of catalytic moieties at the peripheries of dendrimers within a dendrimer generation. In a given generation, higher clustering of catalytic moieties greatly assisted multiple C-C bond formations than presenting the same in lesser number. The studies demonstrate true benefits of clustering catalytic moieties within a dendrimer generation and the beneficial effects applicable to catalysis of substrates presenting more than one reactive center. (C) 2011 Elsevier B.V. All rights reserved.

NMR spectra of oriented biologically important molecules - The structure of and the internal rotation in N,N'-dimethyluracil

From the proton NMR spectra of Nfl-dimethyluracil oriented in two different nematic solvents, the internal rotation of the methyl groups about the N-C bonds is studied. It has been observed that the preferred conformation of the methyl group having one carbonyl in the vicinity is the one where a C-H bond is in the ring plane pointing toward the carbonyl group. The results are not sensitive to the mode of rotation of the other methyl group. These data are interpreted in terms of the bond polarizations.

Nuclear Magnetic-Resonance Spectra Of Oriented Biologically Important Molecules - The Structure Of And The Internal-Rotation In N,N-Dimethyluracil

From the proton NMR spectra of Nfl-dimethyluracil oriented in two different nematic solvents, the internal rotation of the methyl groups about the N-C bonds is studied. It has been observed that the preferred conformation of the methyl group having one carbonyl in the vicinity is the one where a C-H bond is in the ring plane pointing toward the carbonyl group. The results are not sensitive to the mode of rotation of the other methyl group. These data are interpreted in terms of the bond polarizations.

Structural studies of analgesics and their interactions. VII. Stereoisomerism and disorder in the structure of oxyphenbutazone monohydrate

Oxyphenbutazone, C19H20N203, a metabolite and perhaps the active form of phenylbutazone, is a widely used non-narcotic analgesic and anti-inflammatory pyrazolidinedione derivative. The monohydrate of the compound crystallizes in the triclinic space group Pi with two molecules in a unit cell of dimensions a -- 9.491 (4), b = 10.261 (5), c = 11.036 (3)A and ¢~ = 72.2 (1), fl = 64.3 (1), 7 = 73.0 (1) °. The structure was solved by direct methods and refined to an R value of 0.107 for 1498 observed reflections. The butyl group in the molecule is disordered. The hydroxyl group occupies two sites with unequal occupancies. On account of the asymmetry at the two N atoms and one of the C atoms in the central five-membered ring, the molecule can exist in eight isomeric states, of which four are sterically unfavourable. The disorder in the position of the hydroxyl group can be readily explained on the basis of the existence, with unequal abundances, of all four sterically favourable isomers.The bond lengths and angles in the molecule are similar to those in phenylbutazone. The crystal structure is stabilized by van der Waals interactions, and O-H... O hydrogen bonds involving the carbonyl and the hydroxyl groups as well as a water molecule.

Studies on Unsteady Pressure Fields in the Region of Separating and Reattaching Flows

Experimental studies on the measurement of pressure fields in the region of separating and reattaching flows behind several two-dimensional fore-bodies and one axisymmetric body are reported. In particular, extensive measurements of mean pressure, surface pressure fluctuation, and pressure fluctuation within the flow were made for a series of two-dimensional fore-body shapes consisting of triangular nose with varying included angle. The measurements from different bodies are compared and one of the important findings is that the maximum values of rms pressure fluctuation levels in the shear layer approaching reattachment are almost equal to the maximum value of the surface fluctuation levels.

Molecular Mechanics Studies of Homopolymeric and Mixed Sequence Py.Pu*Pu Triple Helices,

DNA triple helices containing two purine strands and one pyrimidine strand (C.G*G and T.A*A) have been studied, using model building followed by energy minimisation, for different orientations of the third strand resulting from variation in the hydrogen bonding between the Watson-Crick duplex and the third strand and the glycosidic torsion angle in the third strand. Our results show that in the C.G*G case the structure with a parallel orientation of the third strand, resulting from Hoogsteen hydrogen bonds between the third strand and the Watson-Crick duplex, is energetically the most favourable while in the T.A*A case the antiparallel orientation of the third strand, resulting from reverse Hoogsteen hydrogen bonds, is energetically the most favourable. These studies when extended to the mixed sequence triplexes, in which the second strand is a mixture of G and A, correspondingly the third strand is a mixture of G and APT, show that though the parallel orientation is still energetically more favourable, the antiparallel orientation becomes energetically comparable with an increasing number of thymines in the third strand. Structurally, for the mixed triplexes containing G and T in the third strand, it is seen that the basepair non-isomorphism between the C.G*G and the T.A*T triplets can be overcome with some changes in the base pair parameters without much distortion of either the backbone or the hydrogen bonds.

Synthesis of mixed glycosyl disulfides/selenenylsulfides using benzyltriethylammonium tetrathiomolybdate as a sulfur transfer reagent

An easy and mild method has been developed for the synthesis of mixed glycosyl disulfides/selenenylsulfides from glycosyl halides and diaryl/dialkyl dichalcogenides in the presence of benzyltriethylammonium tetrathiomolybdate (BnEt3N)(2)MoS4]. The salient feature of this method is the sulfur transfer from BnEt3N](2)MoS4 to form glycosyl disulfides which with excess tetrathiomolybdate further undergo exchange reaction with other dichalcogenides in a one-pot operation. (C) 2014 Elsevier Ltd. All rights reserved.

Justifying threshold voltage definition for undoped body transistors through ``crossover point'' concept

Two different definitions, one is potential based and the other is charge based, are used in the literatures to define the threshold voltage of undoped body symmetric double gate transistors. This paper, by introducing a novel concept of crossover point, proves that the charge based definition is more accurate than the potential based definition. It is shown that for a given channel length the potential based definition predicts anomalous change in threshold voltage with body thickness variation while the charge based definition results in monotonous change. The threshold voltage is then extracted from drain current versus gate voltage characteristics using linear extrapolation, transconductance and match-point methods. In all the three cases it is found that trend of threshold voltage variation support the charge based definition.

Many-body effects in electrochemisorption : Part III. Beyond mean field and hartree-fock

Several channels provided by many-body couplings — both fermion-fermion and fermion-boson — for the evolution of the chemisorption system are discussed. This provides an opportunity of a systematic study of the effects of correlations reflected through the intricate pole structure of the absorbate Green functions. The results of Newns, Anda and others in the context of chemisorption are generalized.

Many-body effects in electrochemisorption : Part IV. Multi-boson formalism

Several boson subsystems may be involved in electrosorption phenomena. To accommodate this possibility, the one-boson formalism described in Parts I–III is extended to this case. The hierarchy in the superoperator scheme, the evaluation of operator averages for closure and several special cases are indicated. As an illustration, some calculations are presented to indicate the trends of many-body corrections in chemisorption.

Mycobacterium tuberculosis FtsZ requires at least one arginine residue at the C-terminal end for polymerization in vitro

We examined whether C-terminal residues of soluble recombinant FtsZ of Mycobacterium tuberculosis (MtFtsZ) have any role in MtFtsZ polymerization in vitro. MtFtsZ-delta C1, which lacks C-terminal extreme Arg residue (underlined in the C-terminal extreme stretch of 13 residues, DDDDVDVPPFMRR), but retaining the penultimate Arg residue (DDDDVDVPPFMR), polymerizes like full-length MtFtsZ in vitro. However, MtFtsZ-delta C2 that lacks both the Arg residues at the C-terminus (DDDDVDVPPFM), neither polymerizes at pH 6.5 nor forms even single- or double-stranded filaments at pH 7.7 in the presence of 10 mM CaCl2. Neither replacement of the penultimate Arg residue, in the C-terminal Arg deletion mutant DDDDVDVPPFMR, with Lys or His or Ala or Asp (DDDDVDVPPFMK/H/A/D) enabled polymerization. Although MtFtsZ-delta C2 showed secondary and tertiary structural changes, which might have affected polymerization, GTPase activity of MtFtsZ-delta C2 was comparable to that of MtFtsZ. These data suggest that MtFtsZ requires an Arg residue as the extreme C-terminal residue for polymerization in vitro. The polypeptide segment containing C-terminal 67 residues, whose coordinates were absent from MtFtsZ crystal structure, was modeled on tubulin and MtFtsZ dimers. Possibilities for the influence of the C-terminal Arg residues on the stability of the dimer and thereby on MtFtsZ polymerization have been discussed.

Complex solitons in Bose-Einstein condensates with two- and three-body interactions

For the first time, we find the complex solitons for a quasi-one-dimensional Bose-Einstein condensate with two-and three-body interactions. These localized solutions are characterized by a power law behaviour. Both dark and right solitons can be excited in the experimentally allowed parameter domain, when two-and three-body interactions are,respectively, repulsive and attractive. The dark solitons travel with a constant speed, which is quite different from the Lieb mode, where profiles with different speeds, bounded above by sound velocity, can exist for specified interaction strengths. We also study the properties of these solitons in the presence of harmonic confinement with time-dependent nonlinearity and loss. The modulational instability and the Vakhitov-Kolokolov criterion of stability are also studied.

Structure and dynamics of benzene in one-dimensional channels

Molecular dynamics investigation of benzene in one-dimensional channel systems A1PO(4)-5, VPI-5, and carbon nanotube is reported. The results suggest that, in all the three host systems, the plane of benzene is almost perpendicular to the channel axis when the molecule is near the center of the channel and the plane of benzene is parallel to the channel axis when the molecule is near the wall of the channel. The density distribution of benzene as a function of channel length, z and the radial distance, r, from the channel axis is also different in the three host structures. Anisotropy in translational diffusion coefficient, calculated in body-fixed frame of benzene, suggests that benzene prefers to move with its plane parallel to the direction of motion in A1PO(4)-5 and VPI-5 whereas in carbon nanotube the motion occurs predominantly with the plane of the benzene perpendicular to the direction of motion.;Anisotropy associated with the rotational motion is seen to alter significantly in confinement as compared to liquid benzene. In A1PO(4)-5, the rotational anisotropy is reversed as compared to liquid benzene thereby suggesting that anisotropy arising out of molecular geometry can be reduced. Reorientational correlation times for C-6 and C-2 axes Of benzene are reported. Apart from the inertial decay of reorientational correlation function due to free, rotation, two other distinct regimes of decay are observed in narrower channels (AIPO(4)-5 and carbon nanotube): (i) an initial fast decay (0.5-2 ps) and (ii) a slower decay (>2 ps) of reorientational correlation function where C-6 decays slower than C-2 Similar to what is observed in liquid benzene. In the initial fast decay, it is seen that the decay for C-6 is faster than C-2 which is in contrast to what is observed in liquid benzene or for benzene confined in VPI-5.

Crystal structure and conformation study of N-methyl-t-3-methyl-r-2, c-6-diphenylpiperidin-4-one thiosemicarbazone

Thiosemicarbazones are having the ability to bind with metal and inhibit the enzyme ribonucleoside diphosphate reductase(RDR),an enzyme which is involved in the synthesis of DNA precursors in the mammalian cells.The title compound N-methyl-t-3-methyl-r-2, c-6-diphenylpiperidin-4-one thiosemicarbazone (NMMDPT), CCDC 218052, was prepared using Mannich reaction and characterized by X-ray diffraction methods.The crystal data are:C20H24N4S; M.W= 352.49, triclinic,space group P (1) over bar, a = 8.467(2)angstrom, b = 10.228(2)angstrom, c = 12.249(2)angstrom; lpha=92.595(3)degrees, beta=104.173(3)degrees, gamma=13.628(3)degrees; V=930.0(3)angstrom(3), Z=2, D-cal=1.259Mgm(-3),mu=0.184mm(-1),lambda (MoKalpha)=0.71073 angstrom, final R1 and wR2 are 0.0470 and 0.1052, respectively. The piperidine rings adopt chair conformation. The planar phenyl rings are oriented equatorially at 2,6-positions of the piperidine ring. The molecular packing can be viewed as dimers held together by two N-H...S types of intermolecular hydrogen bonds. Weak C-H...pi interactions also support the stability of the molecules in the crystal in addition to van der Waals forces. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.