Intramolecular Hydrolysis of Coordinated Acetonitrile in a Binuclear Complex of Cobalt(III): X-Ray Crystallographic Analysis of Salts of [(tren)Co(μ-NH2,μ-L)Co(tren)]4+(L=OH, CH3C(O)NH)

1990 ◽  
Vol 43 (4) ◽  
pp. 643 ◽  
Author(s):  
NW Alcock ◽  
II Creaser ◽  
NJ Curtis ◽  
L Roecker ◽  
AM Sargeson ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Binuclear Complex ◽  
Binding Mode ◽  
Crystallographic Analysis ◽  
Bridging Ligands ◽  
X Ray ◽  
Hydrolysis Of

A synthesis of [( tren )Co(μ-NH2,μ-OH)Co( tren )]4+(3)( tren = tris (2- aminoethyl )amine) is reported along with a series of derivatives: [( tren ) XCo (μ-NH2) CoX ( tren )]n+, where X = CF3SO3- (n = 3)(4), X = CH3CN (n = 5)(5), and [( tren )Co(μ-NH2,μ-CH3C(O)NH)Co( tren )]4+ (6). The substitution of (4) by CH3CN to yield (5) was studied in CH3CN at 20°C, k = 9.0×10-3 s-1, and the intramolecular hydrolysis of (5) to yield the bridging acetamide complex (6) was studied at various acid concentrations. The X-ray crystal structures were determined for (3b) (exafluorophosphate, dihydrate) and (6b) (dithionate, tetrahydrate ). Both crystals are monoclinic, respectively P21/n with a 11.082(2), b 10.402(2), c 15.611(2)Ǻ, β 99.13(2)°, Z 2, and C2/c with a 14.328(2), b 14.046(1), c 16.497(2)Ǻ, β 101.90(1)°, Z 4. For the salt of (3), 2389 data with 1 ≥ 2σ(I) were refined to R 0.070 ( Rw 0.066), and, for the salt of (6), 3087 data with I ≥ 3σ(I) were refined to R 0.041 ( Rw 0.056). Both ions lie on pseudo-symmetric sites involving disorder of the bridging ligands . The structures establish the binding mode of the acetamido ion and the orientation of the tren groups in the isolated complexes.

Synthesen und Strukturen von 2,5-Bis(2-arylvinyl)-1,4-benzochinonen und deren photochemisches Verhalten im Kristall / Syntheses and Crystal Structures of 2,5-Bis(2-arylvinyl)-1,4-benzoquinones and their Photochemical Reactivity in the Crystalline State

1993 ◽  
Vol 48 (10) ◽  
pp. 1411-1418 ◽  
Author(s):  
Hermann Irngartinger ◽  
Jochen Lichtenthäler ◽  
Dieter Fenske ◽  
Gerhard Baum
Keyword(s):  
Crystal Structures ◽  
Anodic Oxidation ◽  
Crystalline State ◽  
Double Bonds ◽  
Resonance Structures ◽  
Photochemical Reactivity ◽  
X Ray ◽  
Bond Lengths ◽  
Intermolecular Distances ◽  
Hydrolysis Of

The 2,5-bis(2-arylvinyl)-1,4-benzoquinones 1a-1e are formed from hydrolysis of their corresponding ketals 5 which are generated by anodic oxidation of the corresponding 1,4-dimethoxybenzene derivatives 4. The crystal structures of the quinone compounds 1a, 1d and 1e have been determined by X-ray analyses. The bond lengths of the quinone system are influenced by polar resonance structures. An α-type packing mode is observed for the three crystal structures of compounds 1. The vinylic double bonds have short intermolecular distances (1a: 4.417(5), 1d: 3.653(2), 1e: 4.224(5) Å). Only the crystals of 1d with the shortest contacts are photoreactive

Imidazole/benzimidazole-modified cyclotriphosphazenes as highly selective fluorescent probes for Cu2+: synthesis, configurational isomers, and crystal structures

2017 ◽  
Vol 46 (28) ◽  
pp. 9140-9156 ◽  
Author(s):  
Aylin Uslu ◽  
Süreyya Oğuz Tümay ◽  
Ahmet Şenocak ◽  
Fatma Yuksel ◽  
Elif Özcan ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Fluorescent Probes ◽  
Copper Ion ◽  
Crystallographic Analysis ◽  
Ion Detection ◽  
X Ray

We present a comprehensive work and discuss the fluoroprobe properties of synthesized compounds for copper ion detection with a stereochemical approach using X-ray crystallographic analysis results.

scholarly journals Benzylaminoethyureido-Tailed Benzenesulfonamides: Design, Synthesis, Kinetic and X-ray Investigations on Human Carbonic Anhydrases

2020 ◽  
Vol 21 (7) ◽  
pp. 2560 ◽  
Author(s):  
Majid Ali ◽  
Murat Bozdag ◽  
Umar Farooq ◽  
Andrea Angeli ◽  
Fabrizio Carta ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Design Strategy ◽  
Binding Mode ◽  
Crystallographic Analysis ◽  
Carbonic Anhydrases ◽  
Detailed Structure ◽  
Design Synthesis ◽  
X Ray ◽  
Structure Activity ◽  
New Compounds

A drug design strategy of carbonic anhydrase inhibitors (CAIs) belonging to sulfonamides incorporating ureidoethylaminobenzyl tails is presented. A variety of substitution patterns on the ring and the tails, located on para- or meta- positions with respect to the sulfonamide warheads were incorporated in the new compounds. Inhibition of human carbonic anhydrases (hCA) isoforms I, II, IX and XII, involving various pathologies, was assessed with the new compounds. Selective inhibitory profile towards hCA II was observed, the most active compounds being low nM inhibitors (KIs of 2.8–9.2 nM, respectively). Extensive X-ray crystallographic analysis of several sulfonamides in an adduct with hCA I allowed an in-depth understanding of their binding mode and to lay a detailed structure-activity relationship.

Synthesis, Crystal Structures, and Reactions of 2-Oxomalonylbis(arylimidoyl) Chlorides and Hydroxymethane Tris(arylimidoyl) Chlorides

2005 ◽  
Vol 58 (7) ◽  
pp. 522
Author(s):  
Richard J. Bowen ◽  
Judy Caddy ◽  
Mabel E. Coyanis ◽  
Manuel A. Fernandes ◽  
Marcus Layh ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Crystal Structures ◽  
X Ray ◽  
X Ray Crystallography ◽  
Hydrolysis Of

The 2-oxomalonylbis(arylimidoyl) chlorides [C6H3(R2-2,6)N=CCl]2CO (R = Me, 3a; Pri, 3b; H, 3c) were synthesized from C6H3(R2-2,6)NHCHO and an excess of (COCl2)3 and their reaction with various nucleophiles was studied. Successive hydrolysis of 3a led to the formation of [C6H3(Me2-2,6)N=CCl]3COH 4a and [C6H3(Me2-2,6)NHCO]3COH 5a, while treatment of 3a with HAuCl4(H2O)x gave {[C6H3(Me2-2,6)N(H)=CCl][C6H3(Me2-2,6)NHCO]2COH}AuCl4 6a. All compounds were fully characterized by microanalysis, NMR spectroscopy, mass spectrometry, and, in the case of 3a, 4a, 5a, and 6a, by X-ray crystallography.

Synthesis and Crystal Structures of New 1,3-Disubstituted Imidazoline-2-thiones

2013 ◽  
Vol 68 (11) ◽  
pp. 1239-1252 ◽  
Author(s):  
Gerhard Laus ◽  
Volker Kahlenberg ◽  
Klaus Wurst ◽  
Thomas Müller ◽  
Holger Kopacka ◽  
...  
Keyword(s):  
Bond Length ◽  
Crystal Structures ◽  
1H Nmr ◽  
Significant Contribution ◽  
Resonance Structure ◽  
X Ray Diffraction ◽  
Reference Compound ◽  
X Ray ◽  
Hydrolysis Of ◽  
By Products

Two methods (MeOH/K2CO3, pyridine/Et3N) were assessed for the introduction of sulfur into the 2-position of 1,3-disubstituted quaternary imidazolium salts 1-9 (Cl, I, BF4, PF6, CH3OSO3 were used as anions) to yield nine 1,3-disubstituted imidazoline-2-thiones 10-18 (1, 10: R1 = CH3, R2 = CH3; 2, 11: R1 = OCH2Ph, R2 = CH3; 3, 12: R1 = OCH3, R2 = CH3; 4, 13: R1 = OCH3, R2 = OCH3; 5, 14: R1 = NH2, R2 = CH2Ph; 6, 15: R1 = NCHPh, R2 = CH3; 7, 16: R1 = NH2, R2 = CH3; 8, 17: R1 = NCHPh, R2 = NCHPh; 9, 18: R1 = NH2, R2 = OCH3). Compounds 11-18 represent N-alkyloxy and N-amino imidazoline-2-thiones, whereas 10 served as reference compound. The first method was advantageous for the conversion 1 → 10 due to faster reaction, whereas in the reaction 2 → 11 considerable amounts of by-products were formed. Pure thiones 11, 14, 16, 17, and 18 were obtained only by the second method. Both methods worked for the synthesis of the methoxy derivatives 12 and 13 from 3 and 4, and the benzylideneamino derivative 15 from 6. 1-Amino-3- methylimidazoline-2-thione (16) was also prepared by hydrolysis of the benzylideneamino derivative 15. Crystal structures of seven 1,3-disubstituted imidazoline-2-thiones were determined by singlecrystal X-ray diffraction. Intermolecular C-H···S contacts were identified and, additionally, N-H···S interactions in aminothiones 14 and 16. The 1H NMR shifts of 10 and 13 were satisfactorily correlated with the Kamlet-Abboud-Taft π* and b parameters in ten solvents. From the lack of correlation with the a parameter and from the C=S bond length (average 1.68 Å ) a significant contribution of a mesoionic imidazolium-2-thiolate resonance structure seems unlikely.

Chemistry and crystal structures of tetrabenzoylethylene, its photolysis product and tetraacetylethylene

1978 ◽  
Vol 31 (6) ◽  
pp. 1265 ◽  
Author(s):  
JR Cannon ◽  
VA Patrick ◽  
CL Raston ◽  
AH White
Keyword(s):  
Solid State ◽  
Crystal Structures ◽  
Molecular Conformation ◽  
Crystallographic Analysis ◽  
Stable Form ◽  
Photolysis Product ◽  
Molecular Conformations ◽  
X Ray ◽  
The Difference ◽  
The Stability

X-ray crystallographic analysis has revealed that the light-sensitive form (A) and the light-stable form (A') of tetrabenzoylethylene are not valence tautomers but are two crystalline modifications of the same substance. The difference in the stability of these forms to light appears to be a consequence of their different molecular conformations and packing in the solid state. The molecular conformation of the A form is represented by (8) and that of the A' form by (9). The related tetraacetylethylene has the conformation (10) in the solid state. X-ray crystallographic analysis has also revealed that the photolysis product (B) of tetrabenzoylethylene is 4-phenoxy-3,4,6-triphenyl-1H,4H-furo[3,4-c]-furan-1-one (11). ��� The crystal structures of (8), (9), (10) and (11) were determined by X-ray diffraction: diffractometer data at 295 K were refined by least-squares techniques to residuals of 0.064 (2161 'observed' reflections) for (8), 0.057 (1310) for (9), 0.049 (1295) for (10) and 0.061 (1639) for (11). Crystals of (8) are monoclinic, P21/n, a 8.775(5), b 17.352(9), c 30.985(8)Ǻ, β 93.01(3)°, Z 8. Crystals of (9) which contain carbon disulfide are monoclinic, A2/a, a 21.21(2), b 6.181(4), c 20.35(2) Ǻ, β 102.77(7)°, Z 4. Crystals of (10) are monoclinic, P21/n, a 7.540(2), b 4.392(2), c 14.770(4) Ǻ, β 96.29(2)°, Z 2. Crystals of (11) are monoclinic, P1/n, a 14.820(4), b 15.000(3), c 10.819(4)Ǻ, β 106.02(2)°, Z 4.

scholarly journals Crystallization and preliminary X-ray crystallographic analysis of α-glucosidase HaG fromHalomonassp. strain H11

2014 ◽  
Vol 70 (4) ◽  
pp. 464-466 ◽  
Author(s):  
Xing Shen ◽  
Wataru Saburi ◽  
Zuo-Qi Gai ◽  
Keisuke Komoda ◽  
Jian Yu ◽  
...  
Keyword(s):  
Halophilic Bacterium ◽  
Crystallographic Analysis ◽  
Low Molecular Weight ◽  
Glycoside Hydrolase Family ◽  
Molecular Replacement ◽  
Data Set ◽  
X Ray ◽  
Cell Parameters ◽  
Hydrolysis Of ◽  
Hydrolase Family

The α-glucosidase HaG from the halophilic bacteriumHalomonassp. strain H11 catalyzes the hydrolysis of the glucosidic linkage at the nonreducing end of α-glucosides, such as maltose and sucrose, to release α-glucose. Based on its amino-acid sequence, this enzyme is classified as a member of glycoside hydrolase family 13. HaG has three unique characteristics: (i) a very narrow substrate specificity, almost exclusively hydrolyzing disaccharides; (ii) activation by monovalent cations, such as K+, Rb+, Cs+and NH4+; and (iii) high transfer activity of the glucose moiety to the OH group of low-molecular-weight compounds, including glycerol and 6-gingerol. Crystallographic studies have been performed in order to understand these special features. An expression vector was constructed and recombinant HaG protein was overexpressed, purified and crystallized. A data set to 2.15 Å resolution was collected and processed. The crystal belonged to space groupP212121, with unit-cell parametersa= 60.2,b= 119.2,c= 177.2 Å. The structure has been determined by molecular replacement using the isomaltulose synthase PalI as the search model (PDB entry 1m53).

Mononuclear and binuclear Cu(II) complexes of some tridentate aroyl hydrazones. X-ray crystal structures of a mononuclear and a binuclear complex

2013 ◽  
Vol 398 ◽  
pp. 98-105 ◽  
Author(s):  
Satyajit Mondal ◽  
Sumita Naskar ◽  
Ayan Kumar Dey ◽  
Ekkehard Sinn ◽  
Carla Eribal ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Binuclear Complex ◽  
X Ray
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