Chiral and achiral copper(ii) complexes: structure, bonding and biological activities

RSC Advances ◽  
2016 ◽  
Vol 6 (64) ◽  
pp. 59055-59065 ◽  
Author(s):  
Assila Maatar Ben Salah ◽  
Nadhem Sayari ◽  
Houcine Naïli ◽  
Alexander. J. Norquist
Keyword(s):  
Hybrid Materials ◽  
Biological Activities ◽  
Polar Space ◽  
Space Group

A route to noncentrosymmetric hybrid materials is discussed through three noncentrosymmetric materials. These compounds crystallize in either a chiral polar or achiral polar space group, and exhibit high antioxidant and anti-hypertensive activities.

A plastically bendable and polar organic crystal

CrystEngComm ◽  
2021 ◽  
Author(s):  
Sotaro Kusumoto ◽  
Akira Sugimoto ◽  
Daisuke Kosumi ◽  
Yang Kim ◽  
Yoshihiro Sekine ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Polar Space ◽  
Organic Crystal ◽  
Space Group ◽  
High Dielectric

In this communication, an organic crystal of the polar space group Pc that is capable of plastically bending in response to external mechanical stress is reported, and its high dielectric...

Investigation of the Cs x Rb1−x TiOAsO4 Series. II. The Problems of Interpretation of Residual Electron Densities in a Polar Space Group

1998 ◽  
Vol 54 (5) ◽  
pp. 645-651 ◽  
Author(s):  
P. A. Thomas ◽  
M. N. Womersley
Keyword(s):  
Electron Density ◽  
Polar Space ◽  
Worst Case ◽  
Polar Structure ◽  
Space Group ◽  
Disordered Structure ◽  
Strong Inversion ◽  
Residual Electron Density ◽  
Optical Crystal ◽  
True Structure

The problems of refinements of structures in a polar space group, such as Pna21, are illustrated by the example of crystals in the Cs2x Rb2−2x Ti2O2As2O8, caesium rubidium titanyl arsenate, series, which are isostructural with the well known non-linear optical crystal KTiOPO4. It is shown in particular that errors in the data collection and/or refinement tend to contribute positive residual electron density in sites which are related by an inversion operation to the real Cs/Rb sites. This phenomenon is a consequence of the presence of two minima in least-squares space, representing here the possible coordinate sets x,y,z and x,y,−z, for a polar structure and is exacerbated in these structures by the presence of strong inversion psuedo-symmetry. It is shown that in the worst case, the positive residual electron density can be eliminated and an improved agreement to the observed data obtained by refinement of a partially micro-twinned disordered structure in which the Cs/Rb occupancy is split between the main sites and the inversion-related sites. It is argued that the true structure is micro-twinned, including partial occupancy of the additional sites.

Two alkali calcium borates exhibiting second harmonic generation and deep-UV cutoff edges

2019 ◽  
Vol 43 (24) ◽  
pp. 9354-9363
Author(s):  
Peng Ren ◽  
Yun Yang ◽  
Hao Li ◽  
Zhihua Yang ◽  
Shilie Pan
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Polar Space ◽  
Structure Property ◽  
Space Group ◽  
Structure Property Relationships ◽  
Deep Uv

KCa4B3O9 and K0.59Rb0.41Ca4B3O9 crystallize in the polar space group with moderate SHG responses. Calculations were performed to elucidate the structure–property relationships.

scholarly journals From patterns to space groups and the eigensymmetry of crystallographic orbits: a reinterpretation of some symmetry diagrams in IUCr Teaching Pamphlet No. 14

2012 ◽  
Vol 45 (4) ◽  
pp. 834-837
Author(s):  
Leopoldo Suescun ◽  
Massimo Nespolo
Keyword(s):  
Alternative Interpretation ◽  
Polar Space ◽  
Space Group ◽  
Space Groups ◽  
General Orbit

The space group of a crystal pattern is the intersection group of the eigensymmetries of the crystallographic orbits corresponding to the occupied Wyckoff positions. Polar space groups without symmetry elements with glide or screw components smaller than 1/2 do not contain characteristic orbits and cannot be realized in patterns (structures) made by only one crystallographic type of object (atom). The space-group diagram of the general orbit for this type of group has an eigensymmetry that corresponds to a special orbit in a centrosymmetric supergroup of the generating group. This fact is often overlooked, as shown in the proposed solution for Plates (i)–(vi) of IUCr Teaching Pamphlet No. 14, and an alternative interpretation is given.

scholarly journals X-RAY POWDER DIFFRACTION DATA FOR A NEW PIRAZOLINE COMPOUND

2019 ◽  
Vol 16 (33) ◽  
pp. 524-529
Author(s):  
G E DELGADO ◽  
P DELGADO-NIÑO ◽  
R LOBATON ◽  
S-M LIEW ◽  
J JAMALIS
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Biological Activities ◽  
Biological Properties ◽  
Powder Pattern ◽  
Monoclinic Space Group ◽  
Powder Diffraction Data ◽  
Space Group ◽  
Cell Parameters ◽  
Wide Range

Pyrazolines are important agents in medicinal chemistry as a promising scaffold for structural modification and drug development studies due to their wide range of biological activities such as anticancer, antifungal, antibacterial, antidepressant, anticonvulsant, antitubercular, antioxidant, antileishmanial and antiinflammatory activity. These heterocyclic compounds can be prepared by refluxing chalcone with hydrazine hydrate and anhydrous sodium acetate in the presence of glacial acetic acid. The structural characterization, molecular and crystalline structure, of these organic compounds, allows studying their biological properties to know their potential applications. Hence the use of XRPD is very important because it allows obtaining a record to be used as a method of identification. The aim of this investigation was to obtain and reported good quality Xray powder diffraction data the pyrazoline compound 1-(3-(4-iodophenyl)-5-(3-methyl thiophen-2-yl)-4,5-dihydro-1H-pyrazol-1-yl)ethan-1-one, which could be used as potential anti-microbial and anti-cancer agent. The powder pattern was indexed in the monoclinic space group I2/a with unit cell parameters a = 25.440(5) Å, b = 5.124(2) Å, c = 26.261(6) Å, b = 105.75(2)° and figures of merit M20= 38.2 and F20= 66.6 (0.00573, 53). All measured lines were indexed and are consistent with the monoclinic space group. The powder pattern will be included in the Powder Diffraction File database to be used as a reference.

scholarly journals Air-Stable Dy(III)-Macrocycle Enantiomers: From Chiral to Polar Space Group

CCS Chemistry ◽  
2022 ◽  
pp. 1-24
Author(s):  
Zhenhua Zhu ◽  
Chen Zhao ◽  
Quan Zhou ◽  
Shuting Liu ◽  
Xiao-Lei Li ◽  
...  
Keyword(s):  
Polar Space ◽  
Space Group

Reactions between arylhydrazinium chlorides and 2-chloroquinoline-3-carbaldehydes: molecular and supramolecular structures of a hydrazone, a 4,9-dihydro-1H-pyrazolo[3,4-b]quinoline and two 1H-pyrazolo[3,4-b]quinolines

2016 ◽  
Vol 72 (9) ◽  
pp. 670-678 ◽  
Author(s):  
Tholappanavara H. Suresha Kumara ◽  
Gopalpur Nagendrappa ◽  
Nanjappa Chandrika ◽  
Haliwana B. V. Sowmya ◽  
Manpreet Kaur ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Biological Activities ◽  
Three Dimensional ◽  
Stacking Interactions ◽  
Compound I ◽  
Space Group ◽  
Π Stacking ◽  
Wide Range ◽  
A Chain

Hydrazone derivatives exhibit a wide range of biological activities, while pyrazolo[3,4-b]quinoline derivatives, on the other hand, exhibit both antimicrobial and antiviral activity, so that all new derivatives in these chemical classes are potentially of value. Dry grinding of a mixture of 2-chloroquinoline-3-carbaldehyde and 4-methylphenylhydrazinium chloride gives (E)-1-[(2-chloroquinolin-3-yl)methylidene]-2-(4-methylphenyl)hydrazine, C17H14ClN3, (I), while the same regents in methanol in the presence of sodium cyanoborohydride give 1-(4-methylphenyl)-4,9-dihydro-1H-pyrazolo[3,4-b]quinoline, C17H15N3, (II). The reactions between phenylhydrazinium chloride and either 2-chloroquinoline-3-carbaldehyde or 2-chloro-6-methylquinoline-3-carbaldehyde give, respectively, 1-phenyl-1H-pyrazolo[3,4-b]quinoline, C16H11N3, (III), which crystallizes in the space groupPbcnas a nonmerohedral twin havingZ′ = 3, or 6-methyl-1-phenyl-1H-pyrazolo[3,4-b]quinoline, C17H13N3, (IV), which crystallizes in the space groupR\overline{3}. The molecules of compound (I) are linked into sheets by a combination of N—H...N and C—H...π(arene) hydrogen bonds, and the molecules of compound (II) are linked by a combination of N—H...N and C—H...π(arene) hydrogen bonds to form a chain of rings. In the structure of compound (III), one of the three independent molecules forms chains generated by C—H...π(arene) hydrogen bonds, with a second type of molecule linked to the chains by a second C—H...π(arene) hydrogen bond and the third type of molecule linked to the chain by multiple π–π stacking interactions. A single C—H...π(arene) hydrogen bond links the molecules of compound (IV) into cyclic centrosymmetric hexamers having \overline{3} (S6) symmetry, which are themselves linked into a three-dimensional array by π–π stacking interactions.

Darstellung und Kristallstruktur von Di-gold(III)bis(selenit)oxid, Au2(SeO3)2O / Preparation and Crystal Structure of Di-gold(III) Bis(selenite) Oxide, Au2(SeO3)2O

1983 ◽  
Vol 38 (1) ◽  
pp. 10-11 ◽  
Author(s):  
Peter G. Jones ◽  
George M. Sheldrick ◽  
Einhard Schwarzmann ◽  
Andreas Vielmäder
Keyword(s):  
Crystal Structure ◽  
Heavy Atom ◽  
Polar Space ◽  
Light Atom ◽  
Space Group ◽  
Extended Structure ◽  
Selenic Acid ◽  
Oxide Ions

Abstract Au2(SeO2)2O was prepared from gold and excess selenic acid in a sealed tube at 533 K. The crystal structure [Pba2, a = 659.2(2), b = 1183.7(3), c = 399.8(1) pm, Z = 2,R = 0.087] was determined; gold atoms are bridged by oxide ions (lying on twofold axes) and selenite ions. The extended structure consists of polymeric layers parallel to the xy-plane. The light atom positions are inaccurate because of the presence of a heavy atom in a polar space group.

Matching selenium-atom peak positions with a different hand or origin

2002 ◽  
Vol 35 (3) ◽  
pp. 368-370 ◽  
Author(s):  
G. David Smith
Keyword(s):  
Computer Program ◽  
Iterative Procedure ◽  
Polar Axis ◽  
Polar Space ◽  
Selenium Atom ◽  
Space Group ◽  
Space Groups ◽  
Fortran 90 ◽  
Symmetry Operations

An algorithm is described for matching and correlating two or more sets of peaks or atoms. The procedure is particularly useful for matching putative selenium atoms from a selenium-atom substructure as obtained fromEmaps from two or more random-atom trials. The algorithm will work for any space group exceptP1. For non-polar space groups, the procedure is relatively straightforward. For polar space groups, the calculation is performed in projection along the polar axis in order to identify potential matching peaks, and an iterative procedure is used to eliminate incorrect peaks and to calculate the displacement along the polar axis. The algorithm has been incorporated into a computer program,NANTMRF, written in Fortran 90. Less than 0.5 s are required to match 27 peaks in space groupP21, and the output lists the correct origin, enantiomorph, symmetry operations, and provides the relative displacements between pairs of matching peaks.

Inorganic structures in space group P31m; coordinate analysis and systematic prediction of new ferroelectrics

2010 ◽  
Vol 66 (2) ◽  
pp. 173-183 ◽  
Author(s):  
S. C. Abrahams
Keyword(s):  
Crystal Structures ◽  
Aluminum Sulfate ◽  
Polar Space ◽  
Candidate Selection ◽  
Primary Sources ◽  
Structural Determination ◽  
Space Group ◽  
Sources Of Uncertainty ◽  
Upper Limit ◽  
Inorganic Crystal

The 62 entries listed in ICSD release 2009/1 under polar space group P31m correspond to 31 families of inorganic crystal structures, some with only one member. Coordinate analysis reveals, over a wide confidence range, 11 of these families as ferroelectric candidates. One includes the well known improper ferroelectric GASH (guanidinium aluminum sulfate hexahydrate), [(C(NH2)3)Al(SO4)2(H2O)6], another the previously predicted ferroelectric CsNO3 phase II. Those remaining include K3Nb3B2O12, the minerals schairerite, galeite and lizardite 1T, LaNi5D6 and γ-CaNi5D6.1, Ca(OCl)2Ca(OH)2, [N(CH3)4]2Mo3S13, Li17Ag3Sn6 and Cs3As5O9. Candidate selection is based upon detecting an approach by the reported atomic arrangement to the symmetry of a corresponding nonpolar supergroup. A further 13 families are typified by their reduced predictive properties, with four others likely to remain polar at higher temperatures and the remaining three noted as having a unit cell larger than reported or a misassigned space group. The primary sources of uncertainty in structurally based predictions of ferroelectricity are the reliability of the underlying structural determination and the upper limit assigned to the cationic displacement magnitudes required to achieve supergroup symmetry.

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