scholarly journals Method for direct discrimination of intra- and intermolecular hydrogen bonds, and characterization of the G(:A):G(:A):G(:A):G heptad, with scalar couplings across hydrogen bonds

2004 ◽  
Vol 32 (17) ◽  
pp. 5113-5118 ◽  
Author(s):  
H. Sotoya
Keyword(s):  
Hydrogen Bonds ◽  
Scalar Couplings ◽  
Intermolecular Hydrogen Bonds ◽  
Direct Discrimination

Copper(II) and cobalt(II) hydroxypyridinecarboxylates: Synthesis, crystal structures, spectral and magnetic properties

2008 ◽  
Vol 62 (5) ◽  
Author(s):  
Jozef Miklovič ◽  
Peter Segľa ◽  
Dušan Mikloš ◽  
Ján Titiš ◽  
Radovan Herchel ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Crystal Structures ◽  
Magnetic Measurements ◽  
Crystal Structure Analysis ◽  
Amide Group ◽  
Carboxyl Group ◽  
Intermolecular Hydrogen Bonds ◽  
Single Crystal Structure Analysis

AbstractSynthesis and characterization of six copper(II) and cobalt(II) octahedral complexes [M(6-OHpic)2(H2O)2] (6-OHpic is 6-hydroxypicolinato), [M(2-OHnic)2(H2O)2] (2-OHnic is 2-hydroxynicotinato), [Cu(6-OHnic)2(H2O)2] (6-OHnic is 6-hydroxynicotinato) as well as [Co(H2O)6](6-OHnic)2 are reported. Their characterization was carried out using elemental analysis, infrared, and magnetic measurements. Based on IR spectra, N,O-coordination of 6-OHpic (via the oxygen atom of the carboxyl group and the nitrogen atom of the pyridine ring), O,O-asymmetrically chelating coordination of the carboxyl groups as well as ionic coordination of 6-OHnic and chelating O,O-coordination (through the oxygen atom of the carboxyl group and the oxygen atom of the amide group) of keto(amide) tautomer of 2-OHnic were supposed. Moreover, crystal structures of 2-OHnicH and the complex [Co(2-OHnic)2(H2O)2]) were determined by X-ray single crystal structure analysis. The system of hydrogen bonds predominantly stabilizes the keto(amide) tautomer of both 2-hydroxynicotinic acid and 2-OHnic anion in the cobalt(II) complex. Intermolecular hydrogen bonds (between the oxygen atom of the amide group and the hydrogen atom of the NH group) interconnect two neighbouring molecules of 2-OHnicH forming dimers. Cobalt(II) in complex [Co(2-OHnic)2(H2O)2] has nearly a regular compressed tetragonal bipyramidal arrangement.

Synthesis and structural characterization of a new self-assembled disulfide linked meso-tetrakis-porphyrin macromolecular array

2008 ◽  
Vol 12 (07) ◽  
pp. 845-848 ◽  
Author(s):  
Abilio J. F. N. Sobral ◽  
Licinia L. G. Justino ◽  
Ana C. C. Santos ◽  
Joana A. Silva ◽  
Cláudia T. Arranja ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Structural Characterization ◽  
Disulfide Bonds ◽  
Metal Coordination ◽  
Intermolecular Hydrogen Bonds ◽  
Coordination Bonding ◽  
Self Assembled

The synthesis of a new self-assembled porphyrin macrostructure based on disulfide bonds, is presented. This constitutes a new way to directly connect porphyrins in macromolecular arrays, to complement the usual methods of intermolecular hydrogen bonds and metal coordination bonding.

The Molecular and Crystal Structure of an Oxindole Alkaloid (6-Hydroxy-2′-(2-methylpropyl)-3,3′-spirotetrahydropyrrolidino-oxindole)

1972 ◽  
Vol 50 (15) ◽  
pp. 2407-2412 ◽  
Author(s):  
M. N. G. James ◽  
G. J. B. Williams
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Molecular Formula ◽  
Root Bark ◽  
Structural Studies ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
R Factors

A previously unknown alkaloid of molecular formula C15H20O2N2 was isolated from the dried root bark of EleagnusCommutata (Wolf willow or Silverberry). An X-ray analysis was undertaken to complete the structural characterization of the molecule. Columnar crystals obtained from diethyl ether have the unit cell constants, a = 13.1949(10) Å, b = 9.4525(6) Å, c = 12.1186(6) Å, β = 109°47(1)′ and belong to space group P21/c. The structure was solved using an automated symbolic addition procedure and refined by block-diagonal least-squares to weighted and unweighted R factors of 6.25% and 4.30%, respectively. The previous structural studies were shown to be essentially correct except for the incorrect placement of the phenolic hydroxyl on C(5) of the oxindole nucleus. The correct molecular structure is implied by the systematic name given. The —OH group engages in two intermolecular hydrogen bonds with the two nitrogen atoms, but the carbonyl moiety is not involved in any such interactions.

scholarly journals Nuclear magnetic resonance as a quantitative tool to study interactions in biomacromolecules

2005 ◽  
Vol 77 (8) ◽  
pp. 1409-1424 ◽  
Author(s):  
S. Grzesiek ◽  
M. Allan ◽  
F. Cordier ◽  
D. Häussinger ◽  
P. Jensen ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Hydrogen Bonds ◽  
Thermal Unfolding ◽  
Scalar Couplings ◽  
Additional Information ◽  
Resistance Protein ◽  
Nuclear Overhauser ◽  
Nuclear Magnetic

High-resolution nuclear magnetic resonance (NMR) has emerged as one of the most versatile tools for the quantitative study of structure, kinetics, and thermodynamics of biomolecules and their interactions at atomic resolution. Traditionally, nuclear Overhauser enhancements (NOEs) and chemical shift perturbation methods are used to determine molecular geometries and to identify contact surfaces, but more recently, weak anisotropic orientation, anisotropic diffusion, and scalar couplings across hydrogen bonds provide additional information.Examples of such technologies are shown as applied to the quantitative characterization of function and thermodynamics of several biomacromolecules. In particular, (1) the structural and dynamical changes of the TipA multidrug resistance protein are followed upon antibiotic binding, (2) the trimer-monomer equilibrium and thermal unfolding of foldon, a small and very efficient trimerization domain of the T4 phagehead, is described in atomic detail, and (3) the changes of individual protein hydrogen bonds during thermal unfolding are quantitatively followed by scalar couplings across hydrogen bonds.

scholarly journals Azobenzene Functionalized “T-Type” Poly(Amide Imide)s vs. Guest-Host Systems—A Comparative Study of Structure-Property Relations

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1912
Author(s):  
Karolina Bujak ◽  
Anna Kozanecka-Szmigiel ◽  
Ewa Schab-Balcerzak ◽  
Jolanta Konieczkowska
Keyword(s):  
Hydrogen Bonds ◽  
Main Chain ◽  
Synthesis And Characterization ◽  
Structure Property ◽  
Intermolecular Hydrogen Bonds ◽  
Optical Birefringence ◽  
Property Relations ◽  
Methyl Phenyl

This paper describes the synthesis and characterization of new “T-type” azo poly(amide imide)s as well as guest-host systems based on the “T-type” matrices. The matrices possessed pyridine rings in a main-chain and azobenzene moieties located either between the amide or imide groups. The non-covalent polymers contained the molecularly dispersed 4-phenylazophenol or 4-[(4-methyl phenyl)diazinyl]phenol chromophores that are capable of forming intermolecular hydrogen bonds with the pyridine rings. The FTIR spectroscopy and the measurements of the thermal, optical and photoinduced optical birefringence were employed for the determination of the influence of H-bonds and the specific elements of polymer architecture on physicochemical properties. Moreover, the obtained results were compared to those described in our previous works to formulate structure-property relations that may be considered general for the class of “T-type” azo poly(amide imide)s.

A Crystallographic Study of Bis[S-benzyl-5-bromo-2-oxoindolin-3-ylidenemethanehydrazonthioate] Disulfide Solvated with Dimethylsulfoxide

2012 ◽  
Vol 9 (2) ◽  
pp. 87
Author(s):  
Mohd Abdul Fatah Abdul Manan ◽  
M. Ibrahim M. Tahir ◽  
Karen A. Crouse ◽  
Fiona N.-F. How ◽  
David J. Watkin
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Solvent Molecule ◽  
Site Occupancy ◽  
Unit Cell Parameters ◽  
Intermolecular Hydrogen Bonds ◽  
Triclinic Space Group ◽  
Cell Parameters ◽  
Crystallographic Study ◽  
Thiol Form

The crystal structure of the title compound has been determined. The compound crystallized in the triclinic space group P -1, Z = 2, V = 1839 .42( 18) A3 and unit cell parameters a= 11. 0460( 6) A, b = 13 .3180(7) A, c=13. 7321 (8) A, a = 80.659(3 )0, b = 69 .800(3 )0 and g = 77 .007 (2)0 with one disordered dimethylsulfoxide solvent molecule with the sulfur and oxygen atoms are distributed over two sites; S101/S102 [site occupancy factors: 0.6035/0.3965] and 0130/0131 [site occupancy factor 0.3965/0.6035]. The C22-S2 l and C 19-S20 bond distances of 1. 779(7) A and 1. 788(8) A indicate that both of the molecules are connected by the disulfide bond [S20-S21 2.055(2) A] in its thiol form. The crystal structure reveals that both of the 5-bromoisatin moieties are trans with respect to the [S21-S20 and CI 9-Nl 8] and [S20-S21 and C22-N23] bonds whereas the benzyl group from the dithiocarbazate are in the cis configuration with respect to [S21-S20 and C19-S44] and [S20-S21 and C22-S36] bonds. The crystal structure is further stabilized by intermolecular hydrogen bonds of N9-H35···O16 formed between the two molecules and N28-H281 ···O130, N28-H281 ···O131 and C4 l-H4 l l ···O 131 with the solvent molecule.

scholarly journals Organotin(IV) selenate derivatives – Crystal structure of [{(Ph3Sn)2SeO4} ⋅ CH3OH] n

2021 ◽  
Vol 44 (1) ◽  
pp. 213-217
Author(s):  
Waly Diallo ◽  
Hélène Cattey ◽  
Laurent Plasseraud
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Point Of View ◽  
Intermolecular Hydrogen Bonds

Abstract Crystallization of [(Ph3Sn)2SeO4] ⋅ 1.5H2O in methanol leads to the formation of [{(Ph3Sn)2SeO4} ⋅ CH3OH] n (1) which constitutes a new specimen of organotin(IV) selenate derivatives. In the solid state, complex 1 is arranged in polymeric zig-zag chains, composed of alternating Ph3Sn and SeO4 groups. In addition, pendant Ph3Sn ⋅ CH3OH moieties are branched along chains according to a syndiotactic organization and via Sn-O-Se connections. From a supramolecular point of view, intermolecular hydrogen bonds established between the selenate groups (uncoordinated oxygen) and the hydroxyl functions (CH3OH) of the pendant groups link the chains together.

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