Relationship Between Molecular Structure, Single Crystal Packing and Self‐Assembly Behavior: A Case Based on Pyrene Imide Derivatives

π -Cyclopentadienyl 1-phenylcyclopentadiene cobalt crystallizes as orthorhombic needles with a = 29.64 ± 0.04 Å, b = 7.70 ± 0.01 Å, c = 10.68 + 0.02 Å; the space group is Pbca . A three-dimensional single-crystal Fourier and least-squares analysis has converged R to 0.089 for the 815 independent reflexions, σ - and π -bonding from the cyclopentadiene ligand to the cobalt ion is evidenced by the conformation of the ligand together with the detailed carbon-carbon bond lengths (average e. s. d. 0.03 Å). The phenyl group occupies the exo -position rather than the endo -site suggested by spectroscopic techniques. The crystal packing is also discussed.

Download Full-text

The Molecular Structure and Self-Assembly Behavior of Reductive Amination of Oxidized Alginate Derivative for Hydrophobic Drug Delivery

Molecules ◽

10.3390/molecules26195821 ◽

2021 ◽

Vol 26 (19) ◽

pp. 5821

Author(s):

Xiuqiong Chen ◽

Qingmei Zhu ◽

Zhengyue Li ◽

Huiqiong Yan ◽

Qiang Lin

Keyword(s):

Molecular Structure ◽

Drug Delivery ◽

Self Assembly ◽

Reductive Amination ◽

Critical Aggregation Concentration ◽

Gravimetric Analysis ◽

Hydrophobic Drug ◽

Amination Reaction ◽

Raw264.7 Cell ◽

Assembly Behavior

On account of the rigid structure of alginate chains, the oxidation-reductive amination reaction was performed to synthesize the reductive amination of oxidized alginate derivative (RAOA) that was systematically characterized for the development of pharmaceutical formulations. The molecular structure and self-assembly behavior of the resultant RAOA was evaluated by an FT-IR spectrometer, a 1H NMR spectrometer, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), a fluorescence spectrophotometer, rheology, a transmission electron microscope (TEM) and dynamic light scattering (DLS). In addition, the loading and in vitro release of ibuprofen for the RAOA microcapsules prepared by the high-speed shearing method, and the cytotoxicity of the RAOA microcapsules against the murine macrophage RAW264.7 cell were also studied. The experimental results indicated that the hydrophobic octylamine was successfully grafted onto the alginate backbone through the oxidation-reductive amination reaction, which destroyed the intramolecular hydrogen bond of the raw sodium alginate (SA), thereby enhancing its molecular flexibility to achieve the self-assembly performance of RAOA. Consequently, the synthesized RAOA displayed good amphiphilic properties with a critical aggregation concentration (CAC) of 0.43 g/L in NaCl solution, which was significantly lower than that of SA, and formed regular self-assembled micelles with an average hydrodynamic diameter of 277 nm (PDI = 0.19) and a zeta potential of about −69.8 mV. Meanwhile, the drug-loaded RAOA microcapsules had a relatively high encapsulation efficiency (EE) of 87.6 % and good sustained-release properties in comparison to the drug-loaded SA aggregates, indicating the good affinity of RAOA to hydrophobic ibuprofen. The swelling and degradation of RAOA microcapsules and the diffusion of the loaded drug jointly controlled the release rate of ibuprofen. Moreover, it also displayed low cytotoxicity against the RAW264.7 cell, similar to the SA aggregates. In view of the excellent advantages of RAOA, it is expected to become the ideal candidate for hydrophobic drug delivery in the biomedical field.

Download Full-text

Chiral Discrimination of the Diastereomeric Salts with (R)-Nipecotic Acid and Tartaric Acid Derivative

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.781-784.135 ◽

2013 ◽

Vol 781-784 ◽

pp. 135-138

Author(s):

Xiao Xia Sun ◽

Ying Chun Li ◽

Xiao Xiao Zhuang ◽

Yu Hu

Keyword(s):

Molecular Structure ◽

Single Crystal ◽

Tartaric Acid ◽

Self Assembly ◽

Optical Purity ◽

Chiral Discrimination ◽

Single Crystal Diffraction ◽

Nipecotic Acid ◽

High Optical Purity ◽

Diastereomeric Salts

An effective resolving agent, (D)-dibenzoyl tartaric acid (2b), was screened to yield direct resolution of (S)- ethyl nipecotate (1) with high optical purity and yield. Molecular recognition was studied by 1H NMR, IR, DSC and single crystal diffraction of the pair of diastereomeric salts. The less-soluble salt formed a supra molecular structure by enantio differentiating self-assembly.

Download Full-text

4,4'-Bipyridine-2,2',6,6'-tetracarboxamide. Synthesis and Self-Assembling Properties of the Free Base and the 1 : 1 Silver(I) Triflate Complex

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20021236 ◽

2002 ◽

Vol 67 (8) ◽

pp. 1236-1246 ◽

Cited By ~ 5

Author(s):

Petr Sehnal ◽

Petr Holý ◽

Miloš Tichý ◽

Jiří Závada ◽

Ivana Císařová

Keyword(s):

Hydrogen Bonds ◽

Single Crystal ◽

Diffraction Analysis ◽

Self Assembly ◽

Crystal Packing ◽

Amide Hydrogen ◽

Free Base ◽

X Ray Diffraction ◽

X Ray ◽

Self Assembling

Self-assembly of 4,4'-bipyridine-2,2',6,6'-tetracarboxamide and its 1 : 1 silver(I) triflate complex was investigated by single crystal X-ray diffraction analysis. It was found that intermolecular amide-amide hydrogen bonds control the crystal packing of the free base giving rise to infinite zig-zag tapes, whereas an octahedral coordination of the Ag(I) ion with the ligand dominates in the packing of the corresponding complex.

Download Full-text

Accurate prediction of terahertz spectra of molecular crystals of fentanyl and its analogs

Scientific Reports ◽

10.1038/s41598-021-83536-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Chun-Hung Wang ◽

Anthony C. Terracciano ◽

Artёm E. Masunov ◽

Mengyu Xu ◽

Subith S. Vasu

Keyword(s):

Molecular Structure ◽

Crystal Packing ◽

Molecular Crystals ◽

Normal Modes ◽

Rapid Identification ◽

Medical Attention ◽

Dispersion Interactions ◽

Pain Reliever ◽

Fentanyl Analogs ◽

High Bioavailability

AbstractFentanyl is a potent synthetic opioid pain reliever with a high bioavailability that can be used as prescription anesthetic. Rapid identification via non-contact methods of both known and emerging opioid substances in the fentanyl family help identify the substances and enable rapid medical attention. We apply PBEh-3c method to identify vibrational normal modes from 0.01 to 3 THz in solid fentanyl and its selected analogs. The molecular structure of each fentanyl analog and unique arrangement of H-bonds and dispersion interactions significantly change crystal packing and is subsequently reflected in the THz spectrum. Further, the study of THz spectra of a series of stereoisomers shows that small changes in molecular structure results in distinct crystal packing and significantly alters THz spectra as well. We discuss spectral features of synthetic opioids with higher potency than conventional fentanyl such as ohmefentanyl and sufentanil and discover the pattern of THz spectra of fentanyl analogs.

Download Full-text

Synthesis of Bis(Carboranyl)amides 1,1′-μ-(CH2NH(O)C(CH2)n-1,2-C2B10H11)2 (n = 0, 1) and Attempt of Synthesis of Gadolinium Bis(Dicarbollide)

Molecules ◽

10.3390/molecules26051321 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1321

Author(s):

Yasunobu Asawa ◽

Aleksandra V. Arsent’eva ◽

Sergey A. Anufriev ◽

Alexei A. Anisimov ◽

Kyrill Yu. Suponitsky ◽

...

Keyword(s):

Molecular Structure ◽

Single Crystal ◽

Quantum Chemical Calculations ◽

Quantum Chemical ◽

X Ray Diffraction ◽

Stable Conformation ◽

Acyl Chlorides ◽

X Ray ◽

Cesium Fluoride ◽

The Stability

Bis(carboranyl)amides 1,1′-μ-(CH2NH(O)C(CH2)n-1,2-C2B10H11)2 (n = 0, 1) were prepared by the reactions of the corresponding carboranyl acyl chlorides with ethylenediamine. Crystal molecular structure of 1,1′-μ-(CH2NH(O)C-1,2-C2B10H11)2 was determined by single crystal X-ray diffraction. Treatment of bis(carboranyl)amides 1,1′-μ-(CH2NH(O)C(CH2)n-1,2-C2B10H11)2 with ammonium or cesium fluoride results in partial deboronation of the ortho-carborane cages to the nido-carborane ones with formation of [7,7′(8′)-μ-(CH2NH(O)C(CH2)n-7,8-C2B9H11)2]2−. The attempted reaction of [7,7′(8′)-μ-(CH2NH(O)CCH2-7,8-C2B9H11)2]2− with GdCl3 in 1,2-dimethoxy- ethane did not give the expected metallacarborane. The stability of different conformations of Gd-containing metallacarboranes has been estimated by quantum-chemical calculations using [3,3-μ-DME-3,3′-Gd(1,2-C2B9H11)2]− as a model. It was found that in the most stable conformation the CH groups of the dicarbollide ligands are in anti,anti-orientation with respect to the DME ligand, while any rotation of the dicarbollide ligand reduces the stability of the system. This makes it possible to rationalize the design of carborane ligands for the synthesis of gadolinium metallacarboranes on their base.

Download Full-text

Self-Assembly of Single Chain Janus Nanoparticles from Azobenzene-Containing Block Copolymers and Reversible Photoinduced Morphology Transition

Polymer Chemistry ◽

10.1039/d1py00223f ◽

2021 ◽

Author(s):

Wei Wen ◽

Aihua Chen

Keyword(s):

Block Copolymers ◽

Experimental Research ◽

Self Assembly ◽

The Self ◽

Single Chain ◽

Morphology Transition ◽

Janus Nanoparticles ◽

Assembly Behavior

Self-assembly of amphiphilic single chain Janus nanoparticles (SCJNPs) is a novel and promising approach to fabricate assemblies with diversified morphologies. However, the experimental research of the self-assembly behavior of SCJNPs...

Download Full-text