Conformations of the nonbonded and the coordinated ligand nonamethylimidodiphosphoramide (NIPA) in the solid state and in solution. X-ray structure determinations, NMR study, and theoretical calculations on the NIPA molecule and the complex [UO2(NIPA)2C2H5OH](ClO4)2

1984 ◽  
Vol 106 (21) ◽  
pp. 6333-6338 ◽  
Author(s):  
K. Bokolo ◽  
A. Courtois ◽  
Jean Jacques Delpuech ◽  
E. Elkaim ◽  
J. Protas ◽  
...  

2020 ◽  
Vol 73 (6) ◽  
pp. 556
Author(s):  
Simon Grabowsky ◽  
Allan H. White ◽  
Peter C. Healy ◽  
Kim M. Lapere ◽  
Seik Weng Ng ◽  
...  

Neutral mononuclear molecular silver(i) carboxylate complexes of the form [(Ph3P)2Ag(O2XY)] with O2XY=O2CCH2Ph, O2CCHPh2, O2CC(CH3)3, O2CCH2C(CH3)3, and O2CCF3 (compounds 1–4 and 5β) have been investigated in the solid state using single-crystal X-ray structure determinations, 1D 31P CPMAS NMR and 2D 31P–31P CPCOSY NMR measurements, and ab initio computational modelling. The results show that these complexes contain P2AgO2 molecular cores with four-coordinate silver in which the carboxylate ligands are weakly bound to the silver atoms via the two oxygen atoms giving rise to unsymmetrical chelate units. Crystal structure determinations and solid-state NMR spectra have also been analysed for the mononuclear molecular silver(i) nitrate complex [(Ph3P)2Ag(O2NO)] (9α) and two polymorphs of its toluene monosolvate (11α, β). In 9α, the two PPh3 ligands are of the same chirality, whereas in 11α, β, they are opposed. The crystalline environments in the polymorphs have been explored by way of Hirshfeld surface analyses, after quantum-mechanical isolated-molecule calculations had shown that although the molecular energies of the experimental geometries of 9α, and 11α, β are significantly different from each other and from the energies of the optimized geometries, the latter, in contrast, do not differ significantly from each other despite the conformational isomerism. It has further been shown using 9α as an example that the energy dependence on variation of the P–Ag–P angle over a range of ~15° is only ~5 kJ mol−1. All this indicates that the forces arising from crystal packing result in significant perturbations in the experimental geometries, but do not alter the stereoisomerism caused by the donor atom array around the Ag atom. In the NMR study, a strong inverse correlation has been found between 1J(107/109Ag,31P) and the Ag–P bond length across all carboxylate and nitrate compounds.





2001 ◽  
Vol 79 (2) ◽  
pp. 195-200 ◽  
Author(s):  
Gerald W Buchanan ◽  
Majid F Rastegar ◽  
Glenn PA Yap

Benzo-9-crown-3 ether trimerizes in the presence of FeCl3 and aqueous H2SO4 to produce tris(9-crown-3)triphenylene in 25.4% yield. This compound crystallizes in the monoclinic P21/c space group: a = 13.759(2) Å, b = 13.318(2) Å, c = 13.399(2) Å, β = 96.883(2)°, with Z = 4. The three 9-crown-3 ether units of the trimer possess different geometries and there is substantial deviation from coplanarity in the three aromatic rings. 13C NMR chemical shifts in the solid state are consistent with this lack of symmetry and are discussed in terms of the X-ray crystal-structure data.Key words: crown ether, trimerization, stereochemistry.



Tetrahedron ◽  
1997 ◽  
Vol 53 (31) ◽  
pp. 10783-10802 ◽  
Author(s):  
Jairo Quiroga Puello ◽  
Braulio Insuasty Obando ◽  
Concepción Foces-Foces ◽  
Lourdes Infantes ◽  
Rosa María Claramunt ◽  
...  
Keyword(s):  
X Ray ◽  


1980 ◽  
Vol 33 (2) ◽  
pp. 313 ◽  
Author(s):  
PR Jefferies ◽  
BW Skelton ◽  
B Walter ◽  
AH White

Following the suggestion made earlier, on the basis of solution spectroscopy, that a number of eriostyl/nitrobenzoate compounds form charge-transfer self-complexes, a number of these have been investigated structurally by single-crystal X-ray diffraction methods in order to ascertain the presence or otherwise of such interactions in the solid state. The substances thus studied were eriostyl 3,5-dinitrobenzoate (1), eriostyl p-nitrobenzoate (2), tetrahydroeriostyl 3,5-dinitrobenzoate (3), and eriostemyl 3,5-dinitrobenzoate (4);* structure determinations in all cases, although displaying the presence of strong charge-transfer interactions from the two moieties of each molecule, show that the interactions in the solid state are intermolecular in nature.



2011 ◽  
Vol 34 (5-6) ◽  
pp. 153-153
Author(s):  
Libasse Diop

Abstract Solid-state and solution 117Sn nuclear magnetic resonance studies of C2O4(SnPh3)2 have been carried out and found to be in good agreement with the tetrahedral environment of the tin (IV) atom as found from the solid state structure, previously determined by a single crystal X-ray diffraction analysis.



1996 ◽  
Vol 7 (7) ◽  
pp. 457-463 ◽  
Author(s):  
M. Bohner ◽  
J. LeMa�tre ◽  
A. P. LeGrand ◽  
J.-B. D'Espinose de la Caillerie ◽  
P. Belgrand


2009 ◽  
Vol 65 (5) ◽  
pp. 639-646 ◽  
Author(s):  
Edward E. Ávila ◽  
Asiloé J. Mora ◽  
Gerzon E. Delgado ◽  
Ricardo R. Contreras ◽  
Luis Rincón ◽  
...  

The molecular and crystalline structure of ethyl 1′,2′,3′,4′,4a′,5′,6′,7′-octahydrodispiro[cyclohexane-1,2′-quinazoline-4′,1′′-cyclohexane]-8′-carbodithioate (I) was solved and refined from powder synchrotron X-ray diffraction data. The initial model for the structural solution in direct space using the simulated annealing algorithm implemented in DASH [David et al. (2006). J. Appl. Cryst. 39, 910–915] was obtained performing a conformational study on the fused six-membered rings of the octahydroquinazoline system and the two spiran cyclohexane rings of (I). The best model was chosen using experimental evidence from 1H and 13C NMR [Contreras et al. (2001). J. Heterocycl. Chem. 38, 1223–1225] in combination with semi-empirical AM1 calculations. In the refined structure the two spiran rings have the chair conformation, while both of the fused rings in the octahydroquinazoline system have half-chair conformations compared with in-vacuum density-functional theory (DFT) B3LYP/6-311G*, DFTB (density-functional tight-binding) theoretical calculations in the solid state and other related structures from X-ray diffraction data. Compound (I) presents weak intramolecular hydrogen bonds of the type N—H...S and C—H...S, which produce delocalization of the electron density in the generated rings described by graph symbols S(6) and S(5). Packing of the molecules is dominated by van der Waals interactions.



1997 ◽  
Vol 539 (1-2) ◽  
pp. 9-17 ◽  
Author(s):  
Giancarlo Gioia Lobbia ◽  
Patrizio Cecchi ◽  
Roberto Gobetto ◽  
Giuseppe Digilio ◽  
Riccardo Spagna ◽  
...  


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