نتایج جستجو برای: polymorph

تعداد نتایج: 2081  

Journal: :Chemical communications 2005
C Malla Reddy Srinivas Basavoju Gautam R Desiraju

Mechanical shearing of crystals of a polymorph with a layered structure may be used to separate them from harder crystals of a visually indistinguishable polymorph that resist such shearing.

2012
S. Murugavel N. Manikandan D. Kannan M. Bakthadoss

The title compound, C(14)H(13)NO(3)S, (I), is a second monoclinic polymorph. The original polymorph, (II), was reported by Mahía et al. [Acta Cryst. (1999), C55, 2158-2160]. Polymorph (II) crystalllized in the space group P2(1)/c (Z = 4), whereas the title polymorph (I) occurs in the space group P2(1)/n (Z = 4). The dihedral angle between the two aromatic rings is 75.9 (1)° in (I) compared to 8...

2014
Kouzou Matsumoto Masaki Kannami Akira Fuyuhiro Masaji Oda

A second polymorph of the title compound, C21H16N4, is reported. The original polymorph was solved by our group [Matsumoto et al. (2003 ▶). Tetra-hedron Lett. 44, 2861-2864] in the monoclinic space group C2/c and refined to R = 0.050. Now the crystal structure of a tetra-gonal polymorph (space group P-421 c) has been solved and refined to R = 0.036. In the crystal, there are no strong inter-mol...

2011
Iván Brito Javier Vallejos Alejandro Cárdenas Matías López-Rodríguez Michael Bolte

In the title compound, C(15)H(14)N(2)O(4), (I), the mol-ecule lies on a twofold rotation axis which passes through the central C atom of the aliphatic chain, giving one half-mol-ecule per asymmetric unit. The structure is a monoclinic polymorph of the triclinic structure previously reported [Brito, Vallejos, Bolte & López-Rodríguez (2010). Acta Cryst. E66, o792], (II). The most obvious differen...

2007
Iván Brito Aldo Mundaca Alejandro Cárdenas Matías López-Rodríguez

The asymmetric unit of the title compound, C(10)H(6)N(4)O(4)S(2), contains two independent but similar mol-ecules. The structure is a triclinic polymorph of the monoclinic structure reported previously [Brito, Mundaca, Cárdenas, López-Rodríguez & Vargas (2007 ▶). Acta Cryst. E63, o3351-o3352]. The most obvious difference between the two polymorphs is the C-S-S-C torsion angle [-80.13 (16), -79....

Journal: :Chemical communications 2011
Palash Sanphui N Rajesh Goud U B Rao Khandavilli Sreenu Bhanoth Ashwini Nangia

Two new crystalline polymorphs and an amorphous phase of the active curcuminoid ingredient in turmeric are reported. Curcumin polymorph 2 has higher dissolution rate and better solubility than the known polymorph 1.

Journal: :Physical chemistry chemical physics : PCCP 2014
Grzegorz Wesela-Bauman Sergiusz Luliński Janusz Serwatowski Krzysztof Woźniak

Single crystal X-ray structures of two polymorphs of (2-fluoro-3-pyridyl)(2,2'-biphenyl)borinic 8-oxyquinolinate: orthorhombic (space group Pca21), and triclinic (space group P1̄) have been established and analysed. A fast rate of crystallization results in the orthorhombic polymorph, whereas slow crystallization gives the triclinic polymorph. Physicochemical and theoretical results prove that b...

2012
Oualid Talhi José A. Fernandes Diana C. G. A. Pinto Artur M. S. Silva Filipe A. Almeida Paz

The title compound, C(15)H(22)N(2)O(3), was obtained as a by-product of oxidative cleavage of 1,3-dicyclo-hexyl-(3-oxo-2,3-dihydro-benzofuran-2-yl)imidazolidine-2,4-dione. Herein, we report the crystal structure of a second polymorph, which was obtained by crystallization from an ethanol solution at 253 K, instead of slow evaporation of the same solvent at room temperature. While the first poly...

Journal: :Journal of pharmaceutical sciences 2017
Keisuke Maruyoshi Dinu Iuga Abigail E Watts Colan E Hughes Kenneth D M Harris Steven P Brown

The lower detection limit for 2 distinct crystalline phases by 1H magic-angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) is investigated for a minority amount of cimetidine (anhydrous polymorph A) in a physical mixture with the anhydrous HCl salt of cimetidine. Specifically, 2-dimensional 1H double-quantum (DQ) MAS NMR spectra of polymorph A and the anhydrous HCl salt constitut...

Journal: :Acta crystallographica. Section C, Crystal structure communications 2003
Katharine F Bowes Christopher Glidewell John N Low Janet M S Skakle James L Wardell

In the P-1 polymorph of benzanilide or N-phenylbenzamide, C(13)H(11)NO, the molecules are linked into simple C(4) chains by N-H...O hydrogen bonds. The molecules exhibit orientational disorder, but the donor and acceptor in a given hydrogen bond may occur, independently, in either the major or the minor orientation, such that all four possible N-H.O combinations have very similar geometries. Th...

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