X-ray Crystal Structure Analysis of Poly(3-hydroxybutyrate) β-Form and the Proposition of a Mechanism of the Stress-Induced α-to-β Phase Transition

2019 ◽  
Vol 52 (8) ◽  
pp. 2995-3009 ◽  
Author(s):  
Suttinun Phongtamrug ◽  
Kohji Tashiro
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
X Ray ◽  
Β Phase

Isolated versus Condensed Anion Structure III: The Influence of the Cations 1,3-propanediammonium, 1,4-butanediammonium, /n-propylammonium, /n-butylammonium and /n-pentylammonium on Structures and Phase Transitions of ZnBr42- Salts. A81 Br NQR and X-ray Structure Analysis

1997 ◽  
Vol 52 (6-7) ◽  
pp. 550-560 ◽  
Author(s):  
Hideta Ishihara ◽  
Shi-qi Dou ◽  
Keizo Horiuchi ◽  
Helmut Paulus ◽  
Hartmut Fuess ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Phase Transitions ◽  
Hydrogen Bonds ◽  
Structure Analysis ◽  
Phase Ii ◽  
Crystal Structure Analysis ◽  
X Ray ◽  
Dsc Measurements

Abstract The influence of the cations on the condensation of the anions in the salts (A´)Zn(II) Br4 and (A) 2 Zn(II)Br4 is studied by 81Br NQR and X-ray crystal structure analysis. (A´)Zn(II)Br4 (A´ = [H3N(CH2)3NH3]2+) (1) shows a phase transition at 474 K. The phase II of (1) crystallizes with isolated [ZnBr4]2- tetrahedra: monoclinic P21 /n, Z = 4, a = 1108.4 (5), b = 1096.8 (2), c = 1118.5 (6) pm, and β= 117.07(4)° at 296 K. A quartet was observed in the 81Br NQR spectrum of phase II: 61.634,58062, 56.675, and 53.673 MHz (77K); 59.193, 57.448, 56.015, and 52.515 MHz (301 K).(A)2 ZnBr4 (A = [n-H3C(CH2)2NH3 ]+ (2) and [n-H3C(CH2)3NH3 ]+ (3)) also show structures with isolated [ZnBr4]2- tetrahedra. The compound (2) crystallizes with P21/c, Z = 4, a = 771.8(3), b = 1061.9(4), c = 2054.2 (7) pm, and β = 106.75(1)° at 291 K. The compound (3) crystallizes with P21/c, Z = 4, a = 768.9(4), b = 2229.6(10), c = 1071.6(5) pm, and β = 91.70(3)° at 295 K. 81Br NQR and DSC measurements on [H3N(CH2)4 NH3]ZnBr4 (4), and [n-H3 C(CH2)4NH3]2ZnBr4 (5) were also performed. The compound (4) shows several phase transitions at 349 K and higher temperatures, and a quartet in the 81r NQR spectrum could be observed between 77 and 330 K: 65.992,65.544, 59.900, and 50.162 MHz (77 K); 63.787, 62.963, 59.928, and 50.364 MHz (320 K). The compound (5) shows also a phase transition at 244 K, and a quartet of 81Br lines could be observed in the NQR spectrum between 77 and 244 K: 61.279, 58.933, 57.869, and 56.485 MHz (77 K); 59.712, 56.936, 57.409, and 54.793 MHz (240 K). The various influences of the cations, such as size and hydrogen bonds on the condensation of [MX4]2-(M = Zn, Cd; X = C1, Br) are discussed.

scholarly journals Preparative-scale HPLC Resolution of Metallacyclic η3-Allyltricarbonyliron Complexes and Determination of the Absolute Configuration by X-Ray Crystal Structure Analysis

1999 ◽  
Vol 23 (9) ◽  
pp. 578-579
Author(s):  
Rainer Schobert ◽  
Hermann Pfab ◽  
Jutta Böhmer ◽  
Frank Hampel ◽  
Andreas Werner
Keyword(s):  
Crystal Structure ◽  
Silica Gel ◽  
Structure Analysis ◽  
Absolute Configuration ◽  
Crystal Structure Analysis ◽  
Preparative Scale ◽  
X Ray ◽  
The Absolute

Racemates of (η3-allyl)tricarbonyliron lactone complex Fe(CO)3{η1:η3-C(O)XCH2CHCMeCH2} 1a (X = O) and (η3-allyl)tricarbonyliron lactam complex 2a (X = NMe) are resolved on a preparative scale by HPLC on cellulose tris(3,5-dimethylphenyl)carbamate/silica gel RP-8 and the absolute configuration of (-)-2a is determined by X-ray crystal structure analysis.

Second-Generation Inhibitors for the Metalloprotease Neprilysin Based on Bicyclic Heteroaromatic Scaffolds: Synthesis, Biological Activity, and X-Ray Crystal-Structure Analysis

2005 ◽  
Vol 88 (4) ◽  
pp. 731-750 ◽  
Author(s):  
Stefan Sahli ◽  
Brian Frank ◽  
W. Bernd Schweizer ◽  
François Diederich ◽  
Denise Blum-Kaelin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Biological Activity ◽  
Structure Analysis ◽  
Second Generation ◽  
Crystal Structure Analysis ◽  
X Ray

scholarly journals Crystal Structure Analysis of the First Discovered Stability-Enhanced Solid State of Tenofovir Disoproxil Free Base Using Single Crystal X-ray Diffraction

Molecules ◽  
2017 ◽  
Vol 22 (7) ◽  
pp. 1182 ◽  
Author(s):  
Ji-Hun An ◽  
Alice Kiyonga ◽  
Woojin Yoon ◽  
Hyung Ryu ◽  
Jae-Sun Kim ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystal ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
Free Base ◽  
X Ray Diffraction ◽  
X Ray

X-ray crystal structure analysis of parthenin–A sesquiterpene lactone

1994 ◽  
Vol 29 (3) ◽  
pp. 373-378 ◽  
Author(s):  
Vivek K. Gupta ◽  
K. N. Goswami ◽  
K. K. Bhutani
Keyword(s):  
Crystal Structure ◽  
Sesquiterpene Lactone ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
X Ray
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