scholarly journals Two methodologies in the molecular structure and the intermolecular interactions analysis of pharmaceuticals in the solid-state: X-ray diffraction and 13C CPMAS NMR data mining

2015 ◽  
Author(s):  
Dorota Maciejewska ◽  
Jerzy Żabiński ◽  
Mateusz Rezler ◽  
Irena Wolska
2008 ◽  
Vol 63 (11) ◽  
pp. 1267-1275 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Ezzat Khan ◽  
Wolfgang Milius

Abstract Triethylborane, BEt3, can act as a 1,2-hydroborating reagent towards alkyn-1-ylsilanes, depending on the nature of the silane. A mechanism is proposed invoking hydrogen transfer from the β -carbon of one ethyl group, quite different from the 1,2-hydroboration mechanism using tri-n-propylborane, BnPr3. The structure of the products has been confirmed by comparison with that obtained using 9-borabicyclo[3.3.1]nonane, 9-BBN, as a well established 1,2-hydroborating reagent. All products have been characterized by a consistent set of NMR data (1H, 11B, 13C and 29Si NMR). The molecular structure of (Z)-1-dichlorosilyl-1-[9-(9-borabicyclo[3.3.1]nonyl)]-2-phenylethene has been determined by single crystal X-ray diffraction.


1983 ◽  
Vol 36 (9) ◽  
pp. 1865 ◽  
Author(s):  
SF Lincoln ◽  
AM Hounslow ◽  
NJ Maeji ◽  
TW Hambley ◽  
MR Snow ◽  
...  

The molecular structure of N,N,N',N',2,2-hexamethylpropanediamide has been determined in the solid state by X-ray diffraction methods. The structure of Me2NCOCMe2CONMe2 may be broadly described as two planar Me2NCO entities intersecting at the tetrahedral -CMe2- site. The angle between the normals to the two Me2NCO planes is 104.6�, and the two oxygen atoms are disposed outwards from the molecule and away from each other. Proton (270-MHz) n.m.r. studies yield k(320 K) 32.0 � 3.2 s-1, ΔH‡ 69.5 � 0.4 kJ mol-1 and ΔS‡ 0.6 � 1.1 J K-1 mol-1 for rotation of the N-methyl groups about the carbon-nitrogen bonds in CD3NO2 solution. Similar magnitudes for the kinetic parameters characterizing this process are obtained in CDCl3, and CD3CN solutions.


1988 ◽  
Vol 43 (1) ◽  
pp. 49-52 ◽  
Author(s):  
Hubert Schmidbaur ◽  
Jan Ebenhöch

Abstract Trimethylsilylethine (1) has been prepared from C2H2, sodium and Me3SiCl in anisole. The product can be converted into a Grignard reagent Me3SiC≡CMgCl using iPrMgCl. This reagent yields the compounds Me3SiC≡CSiH3, (Me3SiC≡C)2SiH2, (Me3SiC≡C)3SiH, and (Me3SiC≡C)4Si (2-5) when treated with equivalent amounts of H3SiBr, H2SiBr2, HSiCl3, or SiCl4. respectively. The new silanes have been characterized by NMR data. The crystal structure of (Me3SiC≡C)4Si has been determined by single crystal X-ray diffraction. It shows the expected tetrahedral geometry at he central silicon atom with four linear SiC≡CSi linkages.


1985 ◽  
Vol 40 (3) ◽  
pp. 363-367 ◽  
Author(s):  
Fritz Preuss ◽  
Edith Fuchslocher ◽  
William S. Sheldrick

tC4H9N = VCl2(NHtC4H9) and the tert-butylamine complex [tC4H9N=VCl2(NHtC4H9)(NH2tC4H9)] have been prepared by reaction of tC4H9N=VCl3 with NH2tC4H9. 1H and 51V NMR data of these compounds are reported. The complex was investigated by X-ray diffraction analysis; the structure has been found to be a binuclear vanadium complex bridged by two Cl-atoms with a distorted octahedral arrangement of the ligands.


2010 ◽  
Vol 97 (11-12) ◽  
pp. 1055-1066 ◽  
Author(s):  
Ma de la Concepción Foces-Foces ◽  
Félix Hernández Cano ◽  
Rosa Ma Claramunt ◽  
Alain Fruchier ◽  
José Elguero

2010 ◽  
Vol 65 (2) ◽  
pp. 119-127 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Ezzat Khan ◽  
Amin Badshah ◽  
Elias Molla ◽  
Peter Thoma ◽  
...  

The molecular structures of three alkynylsilanes, tetrakis(ethynyl-p-tolyl)silane, 3,3,6,6,-tetramethyl- 3,6-disila-triyne, 3,3,6,6,9,9,-hexamethyl-3,6,9-trisila-tetrayne, and of bis(trimethylstannyl)- ethyne have been determined by X-ray diffraction. The same alkynylsilanes, and in addition 1,2- bis(trimethylsilylethynyl)-1,1,2,2-tetramethyldisliane, were studied by solid-state 13C and 29Si MAS NMR spectroscopy. The results of these measurements were compared with crystallographic evidence and also with relevant solution-state NMR data.


1996 ◽  
Vol 74 (10) ◽  
pp. 1844-1851 ◽  
Author(s):  
Glenn A. Facey ◽  
Terrence J. Connolly ◽  
Corinne Bensimon ◽  
Tony Durst

The solid state disorder of two tetrahydronaphthalene derivatives, N-methyl-N-methoxy-5,6,7,8-tetrahydro-1-naphthamide and 5,6,7,8-tetrahydro-1-naphthoic acid, was studied by solid state NMR and single crystal X-ray diffraction. The X-ray crystal structure of N-methyl-N-methoxy-5,6,7,8-tetrahydro-1-naphthamide was obtained at 123 K. It indicated the presence of two distinct molecular conformations. Solid state 13C CP/MAS NMR data using the dipolar dephasing technique revealed that the two conformations of the molecule are dynamically disordered, while solid state 2H NMR data, collected on a specifically deuterated analog, were used to determine the populations of each conformation as well as an apparent activation energy. Solid state NMR experiments were also used to show that 5,6,7,8-tetrahydro-1-naphthoic acid possesses the same type of dynamic disorder. Key words: deuterium NMR, solid state NMR, dynamic disorder. X-ray, tetrahydronaphthalene derivatives


2000 ◽  
Vol 55 (3-4) ◽  
pp. 262-268 ◽  
Author(s):  
Vladimir A. Ovchynnikov ◽  
Taras P. Timoshenko ◽  
Vladimir M. Amirkhanov ◽  
Joachim Sieler ◽  
Viktor V. Skopenko

Abstract Lanthanide, Carbacylamidophosphate The coordination compounds of the general formula Ln(NO3)3(HL)2(H2O)2 H2O , where Ln = La, Ce -Nd, Sm -Dy, HL = CCl3C(O)NHP(O)[N(CH2CH2)2O]2, dimorpholido-N-tri-chloroacetylphosphorylamide, have been synthesized. The complexes were studied by IR, 1H and 31P NMR and UV-VIS absorption spectroscopies. X-ray diffraction analyses indicate that all synthesized compounds are isostructural. The crystal structure of Nd(NO3)3(HL)2(H2O)2 H2O was solved (monoclinic, a = 11.0467(3), b = 15.9080(5), c = 24.1921(7) Å, β = 96.4080(10)°, space group P21/n, V = 4224.7(2) Å3, Z = 4, R = 0.049, wR = 0.0915). The complex has a molecular structure. The monodentate neutral phosphorictriamide ligands are coordinated to the metal atom via the phosphoryl oxygen atom. The coordination polyhedron of Nd is a sphenocorona; C.N. = 10(60[NO3-], 20[HL], 20[H2O]). It was shown that these compounds in methanol solution are 1:1 electrolytes, and in acetone solution weak electrolytes. According to NMR data in acetone solution the complexes of the lanthanides with the ligand {HL} have axial symmetry.


2002 ◽  
Vol 67 (2) ◽  
pp. 228-234 ◽  
Author(s):  
Axel Fischer ◽  
Frank T. Edelmann ◽  
Klaus Jacob ◽  
Ivan Pavlík ◽  
Martin Pavlišta

The heterodinuclear complex [W(CO)5(Me2NCH2Fc)] (Fc = ferrocenyl) (1) resulting from the reaction of [(dimethylamino)methyl]ferrocene (2) and [W(CO)6] was studied by single-crystal X-ray diffraction. Its molecular structure confirms the coordination of the amine nitrogen in 2 to tungsten (d(W-N) = 2.359(5) Å) and reveals its trans-influence in the W(CO)5 moiety. The structure is discussed in relation to several previously referred spectroscopic (IR, UV-VIS, 13C NMR) data.


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