New Crystal Forms for Biologically Active Compounds. Part 1: Noncovalent Interactions in Adducts of Nevirapine with XB Donors

Abstract

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.

Polymorph Selection of ROY by Flow-Driven Crystallization

“…to avoid differences in the properties and performances of the products [8]. In the pharmaceutical field, the effects of polymorphism are the most critical as the presence of a non-desired polymorph in a mixture can affect stability, solubility, physiological activity or bioavailability of the active ingredients [9,10]. Flows play an important role during the production of crystals of pharmaceutical compounds.…”

Electronic and Optical Properties of Atomic-Scale Heterostructure Based on MXene and MN (M = Al, Ga): A DFT Investigation

“…where that the framework of the quantum theory of atoms in molecules (QTAIM) functional is not considered here, which is also a popular method for simulations [90][91][92][93][94][95][96][97][98][99]. The results show that the Hf2CO2/MN heterostructure is formed by vdW interactions [100,101].…”

“…MXene/MN , E MXene and E MN show the total energy of the Hf 2 CO 2 /MN heterostructure, monolayered Hf 2 CO 2 and MN, respectively. The smaller the binding energy, the more stable the structure of the heterostructure[89], and thus the most stable structure of those six stacking configurations of the heterostructure is decided as the lowest binding energy, which is demonstrated in the AA stacking style of the Hf 2 CO It is worth not-ing that the framework of the quantum theory of atoms in molecules (QTAIM) functional is not considered here, which is also a popular method for simulations[90][91][92][93][94][95][96][97][98][99]. The results show that the Hf 2 CO 2 /MN heterostructure is formed by vdW interactions[100,101].…”

Gold‐Catalyzed Functionalization of Semicarbazides with Terminal Alkynes to Achieve Substituted Semicarbazones

“…In order to confirm or disprove the hypothesis on the existence of N–H ··· O HBs in semicarbazones, and quantify their energies from theoretical viewpoint, we carried out DFT calculations and performed topological analysis of the electron density distribution within the framework of Bader's theory (QTAIM method) for model supramolecular dimeric associates (Table S9). This approach has already been successfully used by us upon studies of various types of HBs (see refs . and references cited therein).…”