scholarly journals New Crystal Forms for Biologically Active Compounds. Part 2: Anastrozole as N-Substituted 1,2,4-Triazole in Halogen Bonding and Lp-π Interactions with 1,4-Diiodotetrafluorobenzene

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 371 ◽  
Author(s):  
Mariya A. Kryukova ◽  
Alexander V. Sapegin ◽  
Alexander S. Novikov ◽  
Mikhail Krasavin ◽  
Daniil M. Ivanov

For an active pharmaceutical ingredient, it is important to stabilize its specific crystal polymorph. If the potential interconversion of various polymorphs is not carefully controlled, it may lead to deterioration of the drug’s physicochemical profile and, ultimately, its therapeutic efficacy. The desired polymorph stabilization can be achieved via co-crystallization with appropriate crystallophoric excipients. In this work, we identified an opportunity for co-crystallization of anastrozole (ASZ), a well-known aromatase inhibitor useful in second-line therapy of estrogen-dependent breast cancer, with a classical XB donor, 1,2,4,5-tetrafluoro-3,6-diiodobenzene (1,4-FIB). In the X-ray structures of ASZ·1.5 (1,4-FIB) co-crystal, different non-covalent interactions involving hydrogen and halogen atoms were detected and studied by quantum chemical calculations and QTAIM analysis at the ωB97XD/DZP-DKH level of theory.

Author(s):  
Kari Raatikainen ◽  
Massimo Cametti ◽  
Kari Rissanen

The series of haloanilinium and halopyridinium salts: 4-IPhNH3Cl (1), 4-IPhNH3Br (5), 4-IPhNH3H2PO4 (6), 4-ClPhNH3H2PO4 (8), 3-IPyBnCl (9), 3-IPyHCl (10) and 3-IPyH-5NIPA (3-iodopyridinium 5-nitroisophthalate, 13), where hydrogen or/and halogen bonding represents the most relevant non-covalent interactions, has been prepared and characterized by single crystal X-ray diffraction. This series was further complemented by extracting some relevant crystal structures: 4-BrPhNH3Cl (2, CCDC ref. code TAWRAL), 4-ClPhNH3Cl (3, CURGOL), 4-FPhNH3Cl (4, ANLCLA), 4-BrPhNH3H2PO4, (7, UGISEI), 3-BrPyHCl, (11, CIHBAX) and 3-ClPyHCl, (12, VOQMUJ) from Cambridge Structural Database for sake of comparison. Based on the X-ray data it was possible to highlight the balance between non-covalent forces acting in these systems, where the relative strength of the halogen bonding C–X···A− (X = I, Br or Cl) and the ratio between the halogen and hydrogen bonds [C–X···A− : D–H···A−] varied across the series.


Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 71 ◽  
Author(s):  
Mariya Kryukova ◽  
Alexander Sapegin ◽  
Alexander Novikov ◽  
Mikhail Krasavin ◽  
Daniil Ivanov

Stabilization of specific crystal polymorphs of an active pharmaceutical ingredient is crucial for preventing uncontrollable interconversion of various crystalline forms, which affects physicochemical properties as well as physiological activity. Co-crystallization with various excipients is an emerging productive way of achieving such stabilization in the solid state. In this work, we identified an opportunity for co-crystallization of antiviral drug nevirapine (NVP) with a classical XB donor, 1,2,4,5-tetrafluoro-3,6-diiodobenzene (1,4-FIB), as well as 1,3-diiodobenzene (1,3-DIB), which has been seldom employed as an XB donor to date. In the X-ray structures of NVP·1,4-FIB and NVP·1,3-DIB co-crystals, different hydrogen and halogen bonding modes were detected and further investigated via DFT calculations as well as topological analysis of the electron density distribution within the framework of the QTAIM method at the M06/DZP-DKH level of theory. Estimated energies of these supramolecular contacts vary from 0.6 to 5.7 kcal/mol.


Author(s):  
Rui Liu ◽  
Yuan Jun Gao ◽  
Wei Jun Jin

Single-crystal X-ray diffraction reveals a series of phosphorescent cocrystals which were assembled by 1,4-diiodotetrafluorobenzene (1,4-DITFB) and either 4,7-dimethyl-1,10-phenanthroline (DMPhe), 4,7-diphenyl-1,10-phenanthroline (DPPhe) or 4,7-dichloro-1,10-phenanthroline (DClPhe)viaC—I...N halogen bonding. These cocrystals, labeled (1), (2) and (3), respectively, are phosphorescent and a distinct change in phosphorescent color can be observed from orange–yellow, green to yellow–green, with well defined vibrational band maxima at 587, 520 and 611 nm for (1), (2) and (3). Based on the dependence of halogen bonding in sites and strength, we discussed the impact of substituents with different electron-withdrawing effects and steric hindrance on intermolecular noncovalent interactions and phosphorescence. The method of inducing and modulating phosphorescence by halogen bonding and other weak non-covalent interactions through changing the substituent groups of molecules should be significant in both theory and the application of optical function materials with predictable and modulated luminescent properties.


Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 354 ◽  
Author(s):  
Lukáš Masaryk ◽  
Ján Moncol ◽  
Radovan Herchel ◽  
Ivan Nemec

The synthesis and properties of new chalcone ligand 4I-L ((2E)-1-[4-(1H-imidazol-1-yl)phenyl]-3-(4-iodophenyl)prop-2-en-1-one) and tetracoordinate Co(II) complex [Co(4I-L)2Cl2], (1a), are reported in this article. Upon recrystallization of 1a, the single crystals of [Co(4I-L)4Cl2]·2DMF·3Et2O (1b) were obtained and crystal structure was determined using X-ray diffraction. The non-covalent interactions in 1b were thoroughly analyzed and special attention was dedicated to interactions formed by the peripheral iodine substituents. The density functional theory (DFT), atoms in molecule (AIM) and noncovalent interaction (NCI) methods and electronic localization function (ELF) calculations were used to investigate halogen bond formed between the iodine functional groups and co-crystallized molecules of diethyl ether.


2021 ◽  
Author(s):  
Zachary Mathe ◽  
Olivia McCubbin Stepanic ◽  
Sergey Peredkov ◽  
Serena DeBeer

Phosphorus is ubiquitous in biochemistry, found in the phosphate groups of nucleic acids and the energy-transferring system of adenine nucleotides (e.g. ATP). Kβ X-ray emission spectroscopy (XES) at phosphorus has...


2011 ◽  
Vol 76 (3) ◽  
pp. 317-328 ◽  
Author(s):  
Zdravko Dzambaski ◽  
Milovan Stojanovic ◽  
Marija Baranac-Stojanovic ◽  
Dragica Minic ◽  
Rade Markovic

Configurational isomerization of stereo-defined 5-substituted and unsubstituted 2-alkylidene-4-oxothiazolidines 1 in the solid state, giving the Z/E mixtures in various ratios, was investigated by 1H-NMR spectroscopy, X-ray powder crystallography and differential scanning calorimetry (DSC). The Z/E composition can be rationalized in terms of non-covalent interactions, involving intermolecular and intramolecular hydrogen bonding and directional non-bonded 1,5-type S...O interactions. X-Ray powder crystallography, using selected crystalline (Z)-4- oxothiazolidine substrates, revealed transformation to the amorphous state during the irreversible Z ? E process. A correlation between previous results on the Z/E isomerization in solution and now in the solid state was established.


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