X-ray and NMR Studies of the DNA Oligomer d(ATATAT):  Hoogsteen Base Pairing in Duplex DNA†

Background: Ischemic heart disease, cerebrovascular accident, and venous thromboembolism have the presence of a thrombotic event in common and represent the most common causes of death within the population. Objective: Since Schiff base copper(II) complexes are able to interact with polyphosphates (PolyP), a procoagulant and potentially prothrombotic platelet agent, we investigated the antiplatelet aggregating properties of two novel tridentate Schiff base ligands and their corresponding copper( II) complexes. Methods: The Schiff base ligands (L1) and (L2), as well as their corresponding copper(II) complexes (C1) and (C2), were synthesized and characterized by chemical analysis, X-ray diffraction, mass spectrometry, and UV-Visible, IR and far IR spectroscopy. In addition, EPR studies were carried out for (C1) and (C2), while (L1) and (L2) were further analyzed by 1H and 13C NMR. Tests for antiplatelet aggregation activities of all of the four compounds were conducted. Results: X-ray diffraction studies show that (L1) and (L2) exist in the enol-imine tautomeric form with a strong intramolecular hydrogen bond. NMR studies show that both ligands are found as enol-imine tautomers in CDCl3 solution. In the solid state, the geometry around the copper(II) ion in both (C1) and (C2) is square planar. EPR spectra suggest that the geometry of the complexes is similar to that observed in the solid state by X-ray crystallography. Compound (C2) exhibited the strongest antiplatelet aggregation activity. Conclusion: Schiff base copper(II) complexes, which are attracting increasing interest, could represent a new approach to treat thrombosis by blocking the activity of PolyP with a potential anticoagulant activity and, most importantly, demonstrating no adverse bleeding events.

Download Full-text

Solution multinuclear (31P,111Cd,77Se) magnetic resonance studies of cadmium complexes of heterocyclic aromatic thiones and the structure of [tetrakis(2(1H)-pyridinethione)cadmium] nitrate, [Cd(C5H5NS)4](NO3)2

Canadian Journal of Chemistry ◽

10.1139/v00-070 ◽

2000 ◽

Vol 78 (5) ◽

pp. 590-597 ◽

Cited By ~ 22

Author(s):

Umarani Rajalingam ◽

Philip AW Dean ◽

Hilary A Jenkins

Keyword(s):

Cadmium Nitrate ◽

Cadmium Complexes ◽

Nmr Studies ◽

X Ray ◽

X Ray Crystallography ◽

Stoichiometric Reaction ◽

Complex Salts ◽

Reduced Temperature ◽

Aromatic Heterocyclic ◽

Phosphine Chalcogenides

The complex salts CdL4(O3SCF3)2 (L = 2(1H)-pyridinethione (Py2SH), 4(1H)-pyridinethione (Py4SH), or 2(1H)-quinolinethione (Q2SH)) have been synthesized by the stoichiometric reaction of Cd(O3SCF3)2 and the appropriate thione. Both ambient-temperature 13C and reduced-temperature 111Cd NMR of CdL4(O3SCF3)2 in solution are consistent with L being bound through sulfur. Reduced-temperature NMR (31P, 77Se, 111Cd, as appropriate) of mixtures of CdL4(O3SCF3)2 and Cd(EPCy3)4(O3SCF3)2 (E = Se, Cy = c-C6H11) and of Cd(EPCy3)4(O3SCF3)2 (E = S, Se) and L in solution provides evidence for various [CdLn(EPCy3)4-n]2+. Similarly, reduced-temperature metal NMR of [CdL4]2+ and [CdL'4]2+ (L, L' = Py2SH, Py4SH, Q2SH; L not equal L') in solution shows the formation of [CdLnL'4-n]2+. Thus it has been demonstrated that at reduced temperature [CdL4]2+ is intact in solution and exchange of L is slow on the timescale of the metal chemical shift differences. From the NMR studies of Cd(EPCy3)4(O3SCF3)2 (E = S, Se):L mixtures, the binding preferences are found to be L > EPCy3 in solution. Similarly, from the reduced temperature metal NMR spectra of mixtures where L and L' compete for Cd(II) in solution, the binding preferences are Py4SH > Py2SH > Q2SH. The structure of Cd(Py2SH)4(NO3)2 (4) has been determined by single crystal X-ray analysis. Colorless crystals of 4 are tetragonal, I4(1)/acd with 8 molecules per unit cell of dimensions a = 18.660(3), c = 15.215(3) Å. The structure is comprised of recognizable NO3- anions and [Cd(Py2SH)4]2+ cations. In the cations, which have S4 symmetry, the ligands are S-bound. A network of NH···O hydrogen bonds links the cations and anions.Key words: aromatic heterocyclic thiones, cadmium complexes, phosphine chalcogenides, 111Cd, 31P, 77Se NMR, X-ray crystallography.

Download Full-text

Comprehensive Characterisation of the Ketoprofen-β-Cyclodextrin Inclusion Complex Using X-ray Techniques and NMR Spectroscopy

Molecules ◽

10.3390/molecules26134089 ◽

2021 ◽

Vol 26 (13) ◽

pp. 4089

Author(s):

Katarzyna Betlejewska-Kielak ◽

Elżbieta Bednarek ◽

Armand Budzianowski ◽

Katarzyna Michalska ◽

Jan K. Maurin

Keyword(s):

Nmr Spectroscopy ◽

Inclusion Complex ◽

Crystal And Molecular Structure ◽

Binding Constants ◽

Nmr Studies ◽

X Ray ◽

Cyclodextrin Inclusion ◽

Powder Samples ◽

Cyclodextrin Inclusion Complex ◽

Co Precipitation

Racemic ketoprofen (KP) and β-cyclodextrin (β-CD) powder samples from co-precipitation (1), evaporation (2), and heating-under-reflux (3) were analysed using X-ray techniques and nuclear magnetic resonance (NMR) spectroscopy. On the basis of NMR studies carried out in an aqueous solution, it was found that in the samples obtained by methods 1 and 2, there were large excesses of β-CD in relation to KP, 10 and 75 times, respectively, while the sample obtained by method 3 contained equimolar amounts of β-CD and KP. NMR results indicated that KP/β-CD inclusion complexes were formed and the estimated binding constants were approximately 2400 M−1, showing that KP is quite strongly associated with β-CD. On the other hand, the X-ray single-crystal technique in the solid state revealed that the (S)-KP/β-CD inclusion complex with a stoichiometry of 2:2 was obtained as a result of heating-under-reflux, for which the crystal and molecular structure were examined. Among the methods used for the preparation of the KP/β-CD complex, only method 3 is suitable.

Download Full-text

ChemInform Abstract: M2Ga6Te10 (M: Li, Na): Two New Non-Metallic Filled β-Manganese Phases - X-Ray and NMR Studies.

ChemInform ◽

10.1002/chin.200015009 ◽

2010 ◽

Vol 31 (15) ◽

pp. no-no

Author(s):

H. J. Deiseroth ◽

L. Kienle ◽

H. Guenther ◽

M. Hartung

Keyword(s):

Nmr Studies ◽

X Ray

Download Full-text

Synthesis, X-ray and solid state NMR studies on silver(I) silanethiolates. Crystal structure of bis[(triphenylphosphine)(tri-o-tolylsilanethiolato)silver(I)]–toluene(1/2), [{Ag[SSi(C6H4Me-o)3](PPh3)}2]·2C6H5Me †

Journal of the Chemical Society Dalton Transactions ◽

10.1039/a903694f ◽

1999 ◽

pp. 3063-3068 ◽

Cited By ~ 16

Author(s):

Jaroslaw Chojnacki ◽

Barbara Becker ◽

Atoni Konitz ◽

Marek J. Potrzebowski ◽

Wieslaw Wojnowski

Keyword(s):

Crystal Structure ◽

Solid State ◽

Solid State Nmr ◽

Nmr Studies ◽

X Ray

Download Full-text

Silylated gallium and indium chalcogenide ring systems as potential precursors to ME (E=O, S) materials

Open Chemistry ◽

10.2478/s11532-013-0255-y ◽

2013 ◽

Vol 11 (7) ◽

pp. 1225-1238

Author(s):

Iliana Medina-Ramírez ◽

Cynthia Floyd ◽

Joel Mague ◽

Mark Fink

Keyword(s):

Thermal Decomposition ◽

Room Temperature ◽

Membered Ring ◽

Molecular Structures ◽

Nmr Studies ◽

X Ray ◽

X Ray Crystallography ◽

High Yields ◽

Vt Nmr ◽

State 1

AbstractThe reaction of R3M (M=Ga, In) with HESiR′3 (E=O, S; R′3=Ph3, iPr3, Et3, tBuMe2) leads to the formation of (Me2GaOSiPh3)2(1); (Me2GaOSitBuMe2)2(2); (Me2GaOSiEt3)2(3); (Me2InOSiPh3)2(4); (Me2InOSitBuMe2)2(5); (Me2InOSiEt3)2(6); (Me2GaSSiPh3)2(7); (Et2GaSSiPh3)2(8); (Me2GaSSiiPr3)2(9); (Et2GaSSiiPr3)2(10); (Me2InSSiPh3)3(11); (Me2InSSiiPr3)n(12), in high yields at room temperature. The compounds have been characterized by multinuclear NMR and in most cases by X-ray crystallography. The molecular structures of (1), (4), (7) and (8) have been determined. Compounds (3), (6) and (10) are liquids at room temperature. In the solid state, (1), (4), (7) and (9) are dimers with central core of the dimer being composed of a M2E2 four-membered ring. VT-NMR studies of (7) show facile redistribution between four- and six-membered rings in solution. The thermal decomposition of (1)–(12) was examined by TGA and range from 200 to 350°C. Bulk pyrolysis of (1) and (2) led to the formation of Ga2O3; (4) and (5) In metal; (7)–(10) GaS and (11)–(12) InS powders, respectively.

Download Full-text

Solid state stereochemistry of crown ethers: X-ray crystal structure and 13C NMR studies of the LiNCS complex of 1,4,7,11-tetraoxacyclotetradecane

Canadian Journal of Chemistry ◽

10.1139/v00-008 ◽

2000 ◽

Vol 78 (3) ◽

pp. 316-321

Author(s):

G W Buchanan ◽

A B Driega ◽

G PA Yap

Keyword(s):

Crystal Structure ◽

Solid State ◽

Crown Ether ◽

13C Nmr ◽

Title Complex ◽

Nmr Studies ◽

Nmr Spectrum ◽

X Ray ◽

Large Amplitude Motion ◽

C Nmr

The title complex is asymmetric in the crystal due to the spatial orientation of the NCS function. The space group has been determined to be P21 with a = 9.496(3), b = 8.736(3), c = 9.676(3) Å, β = 117.859(5)°, and Z = 2. The solid state 13C NMR spectrum is consistent with the lack of symmetry in the crystal and there is little evidence for large amplitude motion in the macrocycle as determined from the dipolar dephased spectrum.Key words: macrocyclic crown ether, lithium complex.

Download Full-text