Influences and the Mechanism of Additives on Intensifying Nucleation and Growth of <i>p</i>‑Methylacetanilide

Effectively manipulating crystal nucleation and growth is an essential issue for controlling the crystal morphology. In this work, the effect of additives on promoting crystal nucleation and growth was investigated from both thermodynamic and kinetic perspectives by using p-methylacetanilide as the model compound. Two additives with amide-terminal and halogen-terminal were selected, and it was found that they can promote the nucleation and crystal growth of p-methylacetanilide. It was found that the existence of 4-bromoacetanilide or 4-chloroacetanilide could decrease the solubility and the interfacial energy of p-methylacetanilide in ethanol, thus leading to an easier nucleation process. Furthermore, by measuring the growth rates of the (1 1 0) and (0 1̅ 1) faces of p-methylacetanilide in the absence and presence of additives, it was found that the raised supersaturation was not the only factor for crystal growth intensification. Molecular simulations revealed that the promotion effect was because the amide-terminal of additives bring the halogen-terminal to the proximity of the p-methylacetanilide surface and disrupt the absorbed ethanol layer, thus eliminating the negative influence of solvent on the surface diffusion of p-methylacetanilide

Understanding the Role of Water in Different Solid Forms of Avibactam Sodium and Its Affecting Mechanism

Hydrates are common in pharmaceutical development, and the formation of hydrates affects the performance of the final product. However, the role that water plays in crystal packing remains unclear. In this study, Avibactam sodium, which has one dihydrate (Form E), one monohydrate (Form A), and two anhydrous forms (Form B and D), was chosen as the model compound to understand this subject. Single crystal structures of four solid forms were obtained and characterized by single X-ray diffraction. The dynamic vapor sorption experiments revealed the moisture-dependent stability increased in the order: Form B < Form D < Form A < Form E. It can be envisaged that the integration of water molecules could noticeably compensate the potential intermolecular interactions, thereby significantly improving the crystal stabilities of hydrates. Furthermore, the hydration of Form B was investigated to understand the integration of water molecules by measuring the critical hydration water activities (aw). The results indicated that both water activities and temperature are vital factors to determine the amount of water molecules existing in crystal lattice. Moreover, to probe the disintegration of water molecules, the dehydration of dihydrate was investigated in detail by solid-state transformation and solvent-mediated transformation experiments. Finally, two-step dehydration and one-step dehydration + recrystallization mechanisms of these different pathways were proposed by analyzing the transformation experiment results and the crystal structure of various solid forms

Solvent Effect on Molecular Conformational Evolution and Polymorphic Manipulation of Cimetidine

In the field of pharmaceutical crystallization, the success of polymorphic manipulation is vital to the performance of pharmaceutical formulations, and the choice of solvents might affect polymorphic outcomes directly. To better understand the relationship between molecular structure in solution and in the crystal, the solvent effect on molecular conformational evolution and polymorph control of cimetidine (CIM) was investigated. Three polymorphs (A, B, and D) of cimetidine (CIM) were prepared, and it was found that conformers selected in crystals could significantly affect crystal packing and polymorph stability. Two-dimensional nuclear Overhauser effect spectroscopy and quantum chemical calculation results reveal that conformer A is the dominant molecular conformer, although conformational distribution is strongly solvent-dependent. Furthermore, Fourier transform infrared spectroscopy and solvation free energy calculation results show that the interaction strength of CIM with solvents increases in the order isopropanol ≈ acetonitrile < methanol < ethylene glycol, affecting the difficulty of desolvation. The results imply that the interaction strength of CIM with solvents may affect the difficulty of desolvation, conformational rearrangement, and final polymorphic outcome. In the end, the potential mechanism of conformational evolution and polymorphic manipulation of CIM was presented

Multistimulus-Responsive Cocrystals of Azobenzene Derivatives with Excellent Elastic Deformation Ability

Stimulus-responsive materials have promising potential applications like actuators, sensors, and flexible electronics, which are important for realizing multidimensional control and improving atomic utilization in future applications. Here, centimeter-scale cocrystals of azobenzene derivatives with excellent elastic deformation ability were designed and prepared. The obtained crystal exhibited a range of striking behaviors, such as cracking, curling, and jumping upon heating and cooling. The mechanism was investigated through detailed crystallographic analysis, experimental tests, and theoretical calculations. The results show that the π-stacking structure formed along the long axis endows the crystals with the ability to resist external forces through elastic deformation, and the anisotropic expansion and contraction of the lattice in response to temperature changes are the source of a series of thermal abrupt behaviors. Furthermore, the photoresponsive property of 4-((4-(propoxy)phenyl)diazenyl)pyridine (APOC) is inherited in the cocrystal, which could rapidly twist under UV illumination. Further simulation and characterization reveal that the bulk stress tilted to the long axis caused by photoisomerization of the host molecules leads to torsion of the crystal. Finally, we successfully applied the crystal as an optical switch in a circuit, taking advantage of its flexibility and photoresponsive properties

Multistimulus-Responsive Cocrystals of Azobenzene Derivatives with Excellent Elastic Deformation Ability

Stimulus-responsive materials have promising potential applications like actuators, sensors, and flexible electronics, which are important for realizing multidimensional control and improving atomic utilization in future applications. Here, centimeter-scale cocrystals of azobenzene derivatives with excellent elastic deformation ability were designed and prepared. The obtained crystal exhibited a range of striking behaviors, such as cracking, curling, and jumping upon heating and cooling. The mechanism was investigated through detailed crystallographic analysis, experimental tests, and theoretical calculations. The results show that the π-stacking structure formed along the long axis endows the crystals with the ability to resist external forces through elastic deformation, and the anisotropic expansion and contraction of the lattice in response to temperature changes are the source of a series of thermal abrupt behaviors. Furthermore, the photoresponsive property of 4-((4-(propoxy)phenyl)diazenyl)pyridine (APOC) is inherited in the cocrystal, which could rapidly twist under UV illumination. Further simulation and characterization reveal that the bulk stress tilted to the long axis caused by photoisomerization of the host molecules leads to torsion of the crystal. Finally, we successfully applied the crystal as an optical switch in a circuit, taking advantage of its flexibility and photoresponsive properties

Multistimulus-Responsive Cocrystals of Azobenzene Derivatives with Excellent Elastic Deformation Ability

Stimulus-responsive materials have promising potential applications like actuators, sensors, and flexible electronics, which are important for realizing multidimensional control and improving atomic utilization in future applications. Here, centimeter-scale cocrystals of azobenzene derivatives with excellent elastic deformation ability were designed and prepared. The obtained crystal exhibited a range of striking behaviors, such as cracking, curling, and jumping upon heating and cooling. The mechanism was investigated through detailed crystallographic analysis, experimental tests, and theoretical calculations. The results show that the π-stacking structure formed along the long axis endows the crystals with the ability to resist external forces through elastic deformation, and the anisotropic expansion and contraction of the lattice in response to temperature changes are the source of a series of thermal abrupt behaviors. Furthermore, the photoresponsive property of 4-((4-(propoxy)phenyl)diazenyl)pyridine (APOC) is inherited in the cocrystal, which could rapidly twist under UV illumination. Further simulation and characterization reveal that the bulk stress tilted to the long axis caused by photoisomerization of the host molecules leads to torsion of the crystal. Finally, we successfully applied the crystal as an optical switch in a circuit, taking advantage of its flexibility and photoresponsive properties

Multistimulus-Responsive Cocrystals of Azobenzene Derivatives with Excellent Elastic Deformation Ability

Stimulus-responsive materials have promising potential applications like actuators, sensors, and flexible electronics, which are important for realizing multidimensional control and improving atomic utilization in future applications. Here, centimeter-scale cocrystals of azobenzene derivatives with excellent elastic deformation ability were designed and prepared. The obtained crystal exhibited a range of striking behaviors, such as cracking, curling, and jumping upon heating and cooling. The mechanism was investigated through detailed crystallographic analysis, experimental tests, and theoretical calculations. The results show that the π-stacking structure formed along the long axis endows the crystals with the ability to resist external forces through elastic deformation, and the anisotropic expansion and contraction of the lattice in response to temperature changes are the source of a series of thermal abrupt behaviors. Furthermore, the photoresponsive property of 4-((4-(propoxy)phenyl)diazenyl)pyridine (APOC) is inherited in the cocrystal, which could rapidly twist under UV illumination. Further simulation and characterization reveal that the bulk stress tilted to the long axis caused by photoisomerization of the host molecules leads to torsion of the crystal. Finally, we successfully applied the crystal as an optical switch in a circuit, taking advantage of its flexibility and photoresponsive properties

Multistimulus-Responsive Cocrystals of Azobenzene Derivatives with Excellent Elastic Deformation Ability

Stimulus-responsive materials have promising potential applications like actuators, sensors, and flexible electronics, which are important for realizing multidimensional control and improving atomic utilization in future applications. Here, centimeter-scale cocrystals of azobenzene derivatives with excellent elastic deformation ability were designed and prepared. The obtained crystal exhibited a range of striking behaviors, such as cracking, curling, and jumping upon heating and cooling. The mechanism was investigated through detailed crystallographic analysis, experimental tests, and theoretical calculations. The results show that the π-stacking structure formed along the long axis endows the crystals with the ability to resist external forces through elastic deformation, and the anisotropic expansion and contraction of the lattice in response to temperature changes are the source of a series of thermal abrupt behaviors. Furthermore, the photoresponsive property of 4-((4-(propoxy)phenyl)diazenyl)pyridine (APOC) is inherited in the cocrystal, which could rapidly twist under UV illumination. Further simulation and characterization reveal that the bulk stress tilted to the long axis caused by photoisomerization of the host molecules leads to torsion of the crystal. Finally, we successfully applied the crystal as an optical switch in a circuit, taking advantage of its flexibility and photoresponsive properties

Multistimulus-Responsive Cocrystals of Azobenzene Derivatives with Excellent Elastic Deformation Ability

Stimulus-responsive materials have promising potential applications like actuators, sensors, and flexible electronics, which are important for realizing multidimensional control and improving atomic utilization in future applications. Here, centimeter-scale cocrystals of azobenzene derivatives with excellent elastic deformation ability were designed and prepared. The obtained crystal exhibited a range of striking behaviors, such as cracking, curling, and jumping upon heating and cooling. The mechanism was investigated through detailed crystallographic analysis, experimental tests, and theoretical calculations. The results show that the π-stacking structure formed along the long axis endows the crystals with the ability to resist external forces through elastic deformation, and the anisotropic expansion and contraction of the lattice in response to temperature changes are the source of a series of thermal abrupt behaviors. Furthermore, the photoresponsive property of 4-((4-(propoxy)phenyl)diazenyl)pyridine (APOC) is inherited in the cocrystal, which could rapidly twist under UV illumination. Further simulation and characterization reveal that the bulk stress tilted to the long axis caused by photoisomerization of the host molecules leads to torsion of the crystal. Finally, we successfully applied the crystal as an optical switch in a circuit, taking advantage of its flexibility and photoresponsive properties

Multistimulus-Responsive Cocrystals of Azobenzene Derivatives with Excellent Elastic Deformation Ability

Stimulus-responsive materials have promising potential applications like actuators, sensors, and flexible electronics, which are important for realizing multidimensional control and improving atomic utilization in future applications. Here, centimeter-scale cocrystals of azobenzene derivatives with excellent elastic deformation ability were designed and prepared. The obtained crystal exhibited a range of striking behaviors, such as cracking, curling, and jumping upon heating and cooling. The mechanism was investigated through detailed crystallographic analysis, experimental tests, and theoretical calculations. The results show that the π-stacking structure formed along the long axis endows the crystals with the ability to resist external forces through elastic deformation, and the anisotropic expansion and contraction of the lattice in response to temperature changes are the source of a series of thermal abrupt behaviors. Furthermore, the photoresponsive property of 4-((4-(propoxy)phenyl)diazenyl)pyridine (APOC) is inherited in the cocrystal, which could rapidly twist under UV illumination. Further simulation and characterization reveal that the bulk stress tilted to the long axis caused by photoisomerization of the host molecules leads to torsion of the crystal. Finally, we successfully applied the crystal as an optical switch in a circuit, taking advantage of its flexibility and photoresponsive properties