ChemInform Abstract: MOLECULAR AND CRYSTAL STRUCTURES OF ((PH3P)2N)(B3H7(NCS)) AND ((PH3P)2N)(B3H7(NCSE)); THE NEED FOR LOW-TEMPERATURE X-RAY CRYSTALLOGRAPHY

1984 ◽  
Vol 15 (52) ◽  
Author(s):  
S. J. ANDREWS ◽  
A. J. WELCH
Keyword(s):  
Low Temperature ◽  
Crystal Structures ◽  
X Ray ◽  
X Ray Crystallography ◽  
Molecular And Crystal Structures

scholarly journals A mixed chirality α-helix in a stapled bicyclic and a linear antimicrobial peptide revealed by X-ray crystallography

2021 ◽  
Author(s):  
Stéphane Baeriswyl ◽  
Hippolyte Personne ◽  
Ivan Di Bonaventura ◽  
Thilo Köhler ◽  
Christian van Delden ◽  
...  
Keyword(s):  
Antimicrobial Peptides ◽  
Antimicrobial Peptide ◽  
Crystal Structures ◽  
X Ray ◽  
X Ray Crystallography ◽  
Α Helix

We report the first X-ray crystal structures of mixed chirality α-helices comprising only natural residues as the example of bicyclic and linear membrane disruptive amphiphilic antimicrobial peptides containing seven l- and four d-residues.

Bis(1-phenyl-1-propyne) complexes of tungsten(II): crystal structures of [WI2(CO)(NCR)(η2-MeC2Ph)2] (R = Me, Et, or Ph)

2001 ◽  
Vol 79 (3) ◽  
pp. 263-271
Author(s):  
Paul K Baker ◽  
Michael GB Drew ◽  
Deborah S Evans
Keyword(s):  
Carbon Monoxide ◽  
Solid State ◽  
Crystal Structures ◽  
Octahedral Geometry ◽  
X Ray ◽  
X Ray Crystallography ◽  
Alkyne Complexes ◽  
First Time

Reaction of [WI2(CO)3(NCMe)2] with two equivalents of 1-phenyl-1-propyne (MeC2Ph) in CH2Cl2, and in the absence of light, gave the bis(1-phenyl-1-propyne) complex [WI2(CO)(NCMe)(η2-MeC2Ph)2] (1) in 77% yield. Treatment of equimolar quantities of 1 and NCR (R = Et, i-Pr, t-Bu, Ph) in CH2Cl2 afforded the nitrile-exchanged products, [WI2(CO)(NCR)(η2-MeC2Ph)2] (2-5) (R = Et (2), i-Pr (3), t-Bu (4), Ph (5)). Complexes 1, 2, and 5 were structurally characterized by X-ray crystallography. All three structures have the same pseudo-octahedral geometry, with the equatorial sites being occupied by cis and parallel alkyne groups, which are trans to the cis-iodo groups. The trans carbon monoxide and acetonitrile ligands occupy the axial sites. In structures 1 and 2, the methyl and phenyl substituents of the 1-phenyl-1-propyne ligands are cis to each other, whereas for the bulkier NCPh complex (5), the methyl and phenyl groups are trans to one another. This is the first time that this arrangement has been observed in the solid state in bis(alkyne) complexes of this type.Key words: bis(1-phenyl-1-propyne), carbonyl, nitrile, diiodo, tungsten(II), crystal structures.

The Through-Bond Interaction of a Sulfur Lone Pair with Oxygenated Substituents in the Thiacyclohexane Framework

2005 ◽  
Vol 58 (7) ◽  
pp. 531
Author(s):  
Laura Andrau ◽  
Jonathan M. White
Keyword(s):  
Low Temperature ◽  
Crystal Structures ◽  
Bond Distance ◽  
Lone Pair ◽  
X Ray ◽  
Ester Derivative ◽  
Bond Interaction ◽  
Derivatives Of ◽  
Electron Demand

Low-temperature X-ray crystal structures were determined on a range of derivatives of 4-thiacyclohexanol 5a of varying electron demand with a view to finding evidence for a through-bond interaction between the sulfur lone pair and the oxygenated substituent. In contrast to earlier suggestions, plots of C–OR bond distance versus pKa (ROH) showed that any interaction between the sulfur and the OR group is unlikely to be of a through-bond origin. Furthermore, unimolecular solvolysis rate measurements on the nosylate ester derivative 5g showed that the sulfur actually retards the reaction slightly in comparison with the corresponding sulfur-free analogue 6.

Synthesis, characterization and crystal structures of novel fluorinated di(thiazolyl)benzene derivatives

2019 ◽  
Vol 6 (6) ◽  
pp. 780-790 ◽  
Author(s):  
Maciej Barłóg ◽  
Ihor Kulai ◽  
Xiaozhou Ji ◽  
Nattamai Bhuvanesh ◽  
Somnath Dey ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Benzene Derivatives ◽  
Stille Coupling ◽  
X Ray ◽  
X Ray Crystallography ◽  
Microwave Assisted

A series of 11 novel fluorinated and non-fluorinated di(thiazolyl)benzenes have been synthesized via microwave assisted Stille coupling and characterized using X-ray crystallography.

Synthesis and crystal structures of three novel benzimidazole/benzoindolizine hybrids

2016 ◽  
Vol 71 (3) ◽  
pp. 231-239 ◽  
Author(s):  
Roumaissa Belguedj ◽  
Sofiane Bouacida ◽  
Hocine Merazig ◽  
Ali Belfaitah ◽  
Aissa Chibani ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Crystal Structures ◽  
Dipolar Cycloaddition ◽  
Dimethyl Acetylenedicarboxylate ◽  
X Ray ◽  
X Ray Crystallography ◽  
Dimethyl Maleate

AbstractThree benzoindolizine derivatives, 1, 2, and 3, were obtained via 1,3-dipolar cycloaddition. The reaction of 1-(2′-benzimidazolylmethyl)isoquinolinium ylides with dimethyl acetylenedicarboxylate gave a mixture of pyrrolo[2,1-a]isoquinoline-1,2-dicarboxylate (1) and 1,10b-dihydropyrrolo[2,1-a]isoquinoline-1,2-dicarboxylate (2) derivatives containing a benzimidazole moiety. The reaction of this isoquinolinium N-ylide with dimethyl maleate gave an unexpected 2,3-dihydropyrrolo[2,1-a]isoquinoline-1,2-dicarboxylate (3). The structures of all reported compounds have been examined by X-ray crystallography, mass spectrometry, and NMR spectroscopy.

Dimethyl-, Disilyl- and Digermylsulfide: Different Intermolecular Contacts in the Solid State

2004 ◽  
Vol 59 (6) ◽  
pp. 635-638 ◽  
Author(s):  
Norbert W. Mitzel ◽  
Udo Losehand
Keyword(s):  
Solid State ◽  
Low Temperature ◽  
Crystal Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intermolecular Contacts

The compounds (H3C)2S, (H3Si)2S and (H3Ge)2S have been crystallised in situ on a diffractometer and their crystal structures determined by low-temperature X-ray diffraction. The molecules are present as monomers in the crystals. The aggregation of the molecules through secondary intermolecular contacts in the crystal is different: (H3C)2S is weakly associated into dimers by S···S contacts, whereas (H3Si)2S and (H3Ge)2S form Si···S and Ge···S contacts in an ice-analogous aggregation motif. Important geometry parameters are (H3C)2S: C-S 1.794(av) Å , C-S-C 99.2(1)°; (H3Si)2S: Si- S 2.143(1) Å , Si-S-Si 98.4°; (H3Ge)2S Ge-S 2.223(2) and 2.230(2) Å , Ge-S-Ge 98.2(1)◦.

New insights into chalcogen bonding provided by co-crystal structures of benzisoselenazolinone derivatives and nitrogen bases

CrystEngComm ◽  
2019 ◽  
Vol 21 (10) ◽  
pp. 1539-1542 ◽  
Author(s):  
Thomas Fellowes ◽  
Jonathan M. White
Keyword(s):  
Crystal Structures ◽  
X Ray ◽  
Nitrogen Bases ◽  
X Ray Crystallography ◽  
Derivatives Of

A number of derivatives of benzisoselenazolinones, including the drug ebselen, have been synthesized, and their interactions with various nitrogen bases characterized through X-ray crystallography.

scholarly journals Sesquiterpene Lactones from Inula oculus-christi

2010 ◽  
Vol 5 (4) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Mahmoud Mosaddegh ◽  
Maryam Hamzeloo Moghadam ◽  
Saeedeh Ghafari ◽  
Farzaneh Naghibi ◽  
Seyed Nasser Ostad ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Crystal Structures ◽  
Spectroscopic Data ◽  
Sesquiterpene Lactones ◽  
X Ray ◽  
X Ray Crystallography ◽  
First Time

Inula oculus-christi L. (Compositae) extract was chromatographed and three sesquiterpene lactones ergolide, gaillardin and pulchellin C were isolated. The structures of these compounds were determined by analysis of their spectroscopic data, and their crystal structures were defined using X-ray crystallography; the isolation of ergolide and pulchellin C is reported for the first time from this species. These three compounds were evaluated for their in vitro cytotoxic activity against MDBK, MCF7 and WEHI164 cells; ergolide and gaillardin exhibited lower and significantly different IC50 values compared with pulchellin C ( p<0.001).

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