Synthetic, structural, and reactivity studies of dirhenium carbonyl complexes of 17.alpha.-ethynylestradiol and phenylacetylene: variable-temperature carbon-13 NMR spectra and x-ray crystal structure of (.mu.-H)(.mu.-C.tplbond.C-R)Re2(CO)7(MeCN)

N,O-chelating dicarbonylhydrazido-palladium complexes were synthesized by treatment of 1,2-bis(trifluoroacetyl)hydrazine with a mixture of a Pd(0) source, [Pd(dba)2] (DBA = dibenzylideneacetone), and four-electron donors including 1,3-bis(diphenylphosphino)propane (DPPP), N,N,N’,N’-tetramethylethylenediamine (TMEDA), and two equivalents of triphenylphosphine. The same products from DPPP and TMEDA could be obtained alternatively by using Pd(OAc)2 through deprotonation of the diacylhydrazine. The five-membered chelate structure was confirmed by NMR spectra and X-ray crystal structure determination. The X-ray structures indicate that the products are formally considered as Pd(II) complexes with a hydrazido(2–) ligand. In the case of the triphenylphosphine-coordinated complex, a fluxional behavior in dichloromethane-d2 was observed by variable temperature NMR experiments, possibly due to structural changes between the square planar and pseudo-tetrahedral geometries.

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Powder study of 3-azabicyclo[3.3.1]nonane-2,4-dione form 2

Acta Crystallographica Section E Structure Reports Online ◽

10.1107/s1600536806023312 ◽

2006 ◽

Vol 62 (7) ◽

pp. o3046-o3048 ◽

Cited By ~ 3

Author(s):

Ashley T Hulme ◽

Philippe Fernandes ◽

Alastair Florence ◽

Andrea Johnston ◽

Kenneth Shankland

Keyword(s):

Crystal Structure ◽

Simulated Annealing ◽

Hydrogen Bonds ◽

Powder Diffraction ◽

Title Compound ◽

Variable Temperature ◽

Polycrystalline Sample ◽

Asymmetric Unit ◽

X Ray ◽

Compound C

A polycrystalline sample of a new polymorph of the title compound, C8H11NO2, was produced during a variable-temperature X-ray powder diffraction study. The crystal structure was solved at 1.67 Å resolution by simulated annealing from laboratory powder data collected at 250 K. Subsequent Rietveld refinement yielded an R wp of 0.070 to 1.54 Å resolution. The structure contains two molecules in the asymmetric unit, which form a C 2 2(8) chain motif via N—H...O hydrogen bonds.

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Investigation of Solvatomorphism and Its Photophysical Implications for Archetypal Trinuclear Au3(1-Methylimidazolate)3

Molecules ◽

10.3390/molecules26154404 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4404

Author(s):

Shengyang Guan ◽

David C. Mayer ◽

Christian Jandl ◽

Sebastian J. Weishäupl ◽

Angela Casini ◽

...

Keyword(s):

Crystal Structure ◽

Solid State ◽

Density Functional ◽

Bulk Material ◽

Variable Temperature ◽

Active Phase ◽

Solvent Free ◽

X Ray Diffraction ◽

X Ray ◽

Aurophilic Interactions

A new solvatomorph of [Au3(1-Methylimidazolate)3] (Au3(MeIm)3)—the simplest congener of imidazolate-based Au(I) cyclic trinuclear complexes (CTCs)—has been identified and structurally characterized. Single-crystal X-ray diffraction revealed a dichloromethane solvate exhibiting remarkably short intermolecular Au⋯Au distances (3.2190(7) Å). This goes along with a dimer formation in the solid state, which is not observed in a previously reported solvent-free crystal structure. Hirshfeld analysis, in combination with density functional theory (DFT) calculations, indicates that the dimerization is generally driven by attractive aurophilic interactions, which are commonly associated with the luminescence properties of CTCs. Since Au3(MeIm)3 has previously been reported to be emissive in the solid-state, we conducted a thorough photophysical study combined with phase analysis by means of powder X-ray diffraction (PXRD), to correctly attribute the photophysically active phase of the bulk material. Interestingly, all investigated powder samples accessed via different preparation methods can be assigned to the pristine solvent-free crystal structure, showing no aurophilic interactions. Finally, the observed strong thermochromism of the solid-state material was investigated by means of variable-temperature PXRD, ruling out a significant phase transition being responsible for the drastic change of the emission properties (hypsochromic shift from 710 nm to 510 nm) when lowering the temperature down to 77 K.

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Variable Temperature X-Ray Crystal Structure Analysis of a Type I Langbeinite: Rb2Cd2(SO4)3.

ChemInform ◽

10.1002/chin.200308010 ◽

2003 ◽

Vol 34 (8) ◽

Author(s):

G. Nalini ◽

T. N. Guru Row

Keyword(s):

Crystal Structure ◽

Structure Analysis ◽

Variable Temperature ◽

Crystal Structure Analysis ◽

Type I ◽

X Ray

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Nuclear magnetic resonance studies on the anions [M(SnCl3)5Cl]4− (M = Ru, Os) and [Ru(SnCl3)5(MeCN)]3−: the X-ray crystal structure of [N(C2H5)4]4[Ru(SnCl3)5Cl]

Canadian Journal of Chemistry ◽

10.1139/v82-193 ◽

1982 ◽

Vol 60 (11) ◽

pp. 1304-1316 ◽

Cited By ~ 18

Author(s):

Louis J. Farrugia ◽

Brian R. James ◽

Claude R. Lassigne ◽

Edward J. Wells

Keyword(s):

Crystal Structure ◽

Nuclear Magnetic Resonance ◽

Nmr Spectroscopy ◽

Nmr Spectra ◽

Octahedral Geometry ◽

Coupling Constants ◽

Order Effects ◽

Magnetic Resonance Studies ◽

X Ray ◽

Crystallographic Study

The octahedral anions [M(SnCl3)5Cl]4− (M = Ru, Os) have been fully characterized by 119Sn FT nmr spectroscopy. For M = Ru, 117Sn and 115Sn nmr spectra were also recorded, and an X-ray crystallographic study was carried out on the tetraethylammonium salt, isolated as a disolvate from acetonitrile. The Ru—Sn bond lengths indicate some degree of dπ–dπ interactions. The slight distortions from octahedral geometry are discussed in connection with the packing of the chlorine atoms. The Sn nmr spectra reveal the first observed coupling to a 99Ru nucleus (I = 5/2, 12.7% natural abundance), very large 2J(119Sn—117Sn) coupling constants, and the first observed second-order effects on a heteronuclear system. The octahedral anion [Ru(SnCl3)5(MeCN)]3− was also synthesized as the tetraethylammonium salt and characterized spectroscopically.

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