scholarly journals Construction of a cross-layer linked G-octamer via conformational control: a stable G-quadruplex in H-bond competitive solvents

2019 ◽  
Vol 10 (15) ◽  
pp. 4192-4199 ◽  
Author(s):  
Ying He ◽  
Yanbin Zhang ◽  
Lukasz Wojtas ◽  
Novruz G. Akhmedov ◽  
David Thai ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Cross Layer ◽  
Conformational Control ◽  
G Quadruplex ◽  
Improved Stability ◽  
First Time

A discrete and well-defined G-octamer system has been established through conformational design of monomers. The crystal structures of G-octamers were obtained for the first time. The covalent linked G-quadruplex exhibited significantly improved stability in both methanol and DMSO.

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 BaAl4 Structure and its Derivatives from the R-Zn-Ga Systems

2012 ◽  
Vol 194 ◽  
pp. 5-9 ◽  
Author(s):  
Yuriy Verbovytskyy ◽  
Antonio Pereira Gonçalves
Keyword(s):  
Crystal Structures ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Powder Diffraction Data ◽  
Space Group ◽  
X Ray ◽  
First Time

Seven new ternary RZn1+xGa3-x (R = Ce, Pr, Nd, Sm, Ho and Er) and R5Zn2Ga17 (R = Ce) phases are synthesized for the first time. Their crystal structures are solved on basis of X-ray powder diffraction data. The above mentioned compounds belong to the BaAl4 (space group I4/mmm) and Rb5Hg19 (space group I4/m) structure types. Details of the structure of the Ce5Zn2Ga17 compound and relationship with RZn2-xGa2+x (BaAl4 type) and R3Zn8-xGa3+x (La3Al11 type) are briefly discussed.

Guanidinatoaluminum complexes: synthesis, crystal structures and reactivities

RSC Advances ◽  
2016 ◽  
Vol 6 (103) ◽  
pp. 101437-101446 ◽  
Author(s):  
Hong-Fei Han ◽  
Zhi-Qiang Guo ◽  
Shao-Feng Zhang ◽  
Jie Li ◽  
Xue-Hong Wei
Keyword(s):  
Crystal Structures ◽  
First Time

The reactivities of the mononuclear guanidinatoaluminum complexes with O2, carbodiimide or H2O were studied for the first time.

scholarly journals New Compounds RE(Zn,Al)8 and Yb4Zn20.3Al12.7 and their Crystal Structures

2006 ◽  
Vol 61 (7) ◽  
pp. 779-784 ◽  
Author(s):  
Ol’ga Stel’makhovych ◽  
Yurij Kuz’ma
Keyword(s):  
Intermetallic Compound ◽  
Crystal Structures ◽  
Structure Type ◽  
Type Structure ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
New Compounds ◽  
First Time ◽  
The Relationship

The crystal structures of several new compounds have been determined using X-ray analysis. The intermetallic compound HoZn5Al3 (a = 8.586(3), c = 16.538(5) Å , RF = 0.0413, RW = 0.0521) has its own structure type (space group I4/mmm), which has been found for the first time. The following compounds are isostructural with the previous one: YZn5.52Al2.48 (a = 8.6183(1), c = 16.5048(3) Å , RI = 0.078, RP = 0.116), DyZn4.96Al3.04 (a = 8.5887(1), c = 16.5002(3) Å , RI = 0.077, RP = 0.114), ErZn5.37Al2.63 (a = 8.5525(2), c =16.3997(5) Å , RI = 0.081, RP = 0.111), TmZn5.64Al2.36 (a = 8.70429(8), c = 16.3943(4) Å , RI = 0.088, RP = 0.095), LuZn5.58Al2.42 (a = 8.5616(1), c= 16.3052(3) Å , RI =0.081, RP =0.101). The intermetallic compound Yb4Zn20.3Al12.7 (a = 8.6183(1), c = 16.5048(3) Å , RI = 0.085, RP = 0.112) adopts the Yb8Cu17Al49 - type structure (space group I4/mmm). The relationship between the HoZn5Al3-type and the Yb8Cu17Al49-type structures is discussed.

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).

scholarly journals Degradation induced lattice anchoring self-passivation in CsPbI3−xBrx

2020 ◽  
Vol 8 (19) ◽  
pp. 9963-9969
Author(s):  
Jingwei Xiu ◽  
Bo Dong ◽  
Elizabeth Driscoll ◽  
Xiyuan Feng ◽  
Abubakar Muhammad ◽  
...  
Keyword(s):  
Solution Approach ◽  
Ambient Environment ◽  
Improved Stability ◽  
First Time

A facile ambient environment solution approach to prepare γ-CsPbI3−xBrx is reported for the first time, leading to samples that exhibit vastly improved stability towards both moisture and heating in air.

Novel isomorphism of two hexagonal non-centrosymmetric hybrid crystals of M(en)3Ag2I4 (M = transition metal Mn2+ or main-group metal Mg2+; en = ethylenediamine)

CrystEngComm ◽  
2018 ◽  
Vol 20 (3) ◽  
pp. 356-361 ◽  
Author(s):  
Xin Chen ◽  
Zhi-Yuan Yao ◽  
Chen Xue ◽  
Zhu-Xi Yang ◽  
Jian-Lan Liu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Complex ◽  
Metal Complexes ◽  
Crystal Structures ◽  
Main Group ◽  
Group Metal ◽  
Main Group Metal ◽  
Hybrid Crystals ◽  
First Time

For the first time, a main-group metal complex is used as a template for the formation of hybrid crystal structures and isomorphic hybrid crystals are obtained using transition and main-group metal complexes.

Temperature dependence of the AV3O7 (A = Ca, Sr) structure

2007 ◽  
Vol 63 (6) ◽  
pp. 836-842 ◽  
Author(s):  
Sebastian Prinz ◽  
Karine M. Sparta ◽  
Georg Roth
Keyword(s):  
Single Crystal ◽  
Temperature Dependence ◽  
Crystal Structures ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Groups ◽  
Temperature Ranges ◽  
First Time

The V4+ (spin ½) oxovanadates AV3O7 (A = Ca, Sr) were synthesized and studied by means of single-crystal X-ray diffraction. The room-temperature structures of both compounds are orthorhombic and their respective space groups are Pnma and Pmmn. The previously assumed structure of SrV3O7 has been revised and the temperature dependence of both crystal structures in the temperature ranges 297–100 K and 315–100 K, respectively, is discussed for the first time.

Crystal structures of the flavonoid Oroxylin A and the regioisomers Negletein and Wogonin

2020 ◽  
Vol 76 (5) ◽  
pp. 490-499
Author(s):  
Ruel Valerio Robles De Grano ◽  
Elena V. Vashchenko ◽  
Madiha Nisar ◽  
Herman H.-Y. Sung ◽  
Valerii V. Vashchenko ◽  
...  
Keyword(s):  
Low Temperature ◽  
Crystal Structures ◽  
Pharmaceutical Formulation ◽  
Oroxylin A ◽  
X Ray ◽  
First Time

The flavonoid Oroxylin A (6-methoxychrysin or 5,7-dihydroxy-6-methoxy-2-phenyl-4H-chromen-4-one, C16H12O5) and its regioisomers are of increasing interest for a variety of bioactive functions and their pharmaceutical formulation is of importance. Previous difficulties in the separation and misidentification of Oroxylin A from its regioisomers Wogonin (8-methoxychrysin or 5,7-dihydroxy-8-methoxy-2-phenyl-4H-chromen-4-one) and Negletein (5,6-dihydroxy-7-methoxyflavone or 5,6-dihydroxy-7-methoxy-2-phenyl-4H-chromen-4-one) render its full structural and powder X-ray characterization highly desirable. The low-temperature (100 K) crystal structures of Oroxylin A, Negletein and Wogonin sesquihydrate are reported for the first time. Wogonin crystallizes in two related but distinct hydrated forms. These have very similar powder diffractograms, indicating that such issues need to be addressed for its pharmaceutical formulation.

New insight into the crystal structure of orthorhombic edingtonite: evidence for a split Ba site

2004 ◽  
Vol 68 (1) ◽  
pp. 167-175 ◽  
Author(s):  
G. D. Gatta ◽  
T. Boffa Ballaran
Keyword(s):  
Crystal Structure ◽  
British Columbia ◽  
Crystal Structures ◽  
Lattice Parameters ◽  
Space Group ◽  
Physicochemical Conditions ◽  
Report Data ◽  
First Time ◽  
Insight Into

AbstractOrthorhombic edingtonite has been found coexisting with tetragonal edingtonite in a specimen from Ice River, British Columbia, Canada.We report data on the composition and crystal structure of the orthorhombic sample. Lattice parameters are: a = 9.5341(6), b = 9.6446(6), c = 6.5108(7)Å, V = 598.68(8)Å 3. The crystal structure was refined in space group P 21212 to R1 = 1.8% using 879 observed reflections. For the first time, evidence for splitting of the extra-framework Ba site in two different sites (Ba1, Ba2), ~0.37 Å apart, is demonstrated. A comparison with the published crystal structures of tetragonal and orthorhombic edingtonite is made.The present result supports the suggestion that the two edingtonite phases are a consequence of different nucleation phenomena and not different physicochemical conditions.

Sign in / Sign up

Export Citation Format

Share Document