Quantitative analysis of solid-state diversity in trifluoromethylated phenylhydrazones

Author(s):  
Dhananjay Dey ◽  
Deepak Chopra

The cooperative roles of various structural motifs associated with the presence of different intermolecular interactions in the formation of molecular crystals are investigated in a series of trifluoromethylated phenylhydrazones. Out of the six compounds analysed, two exhibit three-dimensional structural similarities with geometrically equivalent building blocks, while a third exists as two polymorphic forms crystallized from ethanol solutions at low temperature (277 K) and room temperature (298 K), respectively. The compounds were characterizedviasingle-crystal and powder X-ray diffraction techniques and differential scanning calorimetry. In the absence of any strong hydrogen bonding, the supramolecular constructs are primarily stabilizedviamolecular pairs with a high dispersion-energy contribution, due to the presence of molecular stacking along the molecular backbone along with C—H...π interactions in the solid state, in preference to an electrostatic contribution. The interaction energies for the most stabilizing molecular building blocks are in the range −29 to −43 kJ mol−1. In addition, weak N—H...F, C—H...F and N—H...C interactions and F...F, F...C, F...N and C...N contacts act as secondary motifs, providing additional stability to the crystal packing. The overall molecular arrangements are carefully analysed in terms of their nature and energetics, and the roles of different molecular pairs towards the crystal structure are delineated. A topological study using the quantum theory of atoms in molecules was used to characterize all the atomic interactions in the solid state. It established the presence of (3, −1) bond critical points and the closed-shell nature of all the interactions.

1997 ◽  
Vol 53 (4) ◽  
pp. 569-586 ◽  
Author(s):  
C. B. Aakeröy

The area broadly described as crystal engineering is currently expanding at a brisk pace. Imaginative schemes for supramolecular synthesis, and correlations between molecular structure, crystal packing and physical properties are presented in the literature with increasing regularity. In practice, crystal engineering can be many different things; synthesis, statistical analysis of structural data, ab initio calculations etc. Consequently, we have been provided with a new playing field where chemists from traditionally unconnected parts of the spectrum have exchanged ideas, defined goals and made creative contributions to further progress not only in crystal engineering, but also in other disciplines of chemistry. Crystal engineering is delineated by the nature and structural consequences of intermolecular forces, and the way in which such interactions are utilized for controlling the assembly of molecular building blocks into infinite architectures. Although it is important to acknowledge that a crystal structure is the result of a subtle balance between a multitude of non-covalent forces, this article will focus on design strategies based upon the hydrogen bond and will present a range of approaches that have relied on the directionality and selectivity of such interactions in the synthesis of predictable one-, two- and three-dimensional motifs.


2018 ◽  
Vol 74 (4) ◽  
pp. 452-459 ◽  
Author(s):  
A. Jaquelin Cárdenas-Valenzuela ◽  
Jesús Baldenebro-López ◽  
Jorge A. Guerrero-Álvarez ◽  
Herbert Höpfl ◽  
Daniel Glossman-Mitnik ◽  
...  

Boronic esters are useful building blocks for crystal engineering and the generation of supramolecular architectures, including macrocycles, cages and polymers (one-, two- and three-dimensional), with potential utility in diverse fields such as separation, storage and luminescent materials. The novel dinuclear cyanophenylboronic ester described herein, namely 4,4′-(2,4,8,10-tetraoxa-3,9-diboraspiro[5.5]undecane-3,9-diyl)dibenzonitrile, C19H16B2N2O4, was prepared by condensation of 4-cyanophenylboronic acid and pentaerythritol and fully characterized by elemental analysis, IR and NMR (1H and 11B) spectroscopy, single-crystal X-ray diffraction analysis and TG-DSC (thermogravimetry–differential scanning calorimetry) studies. In addition, the photophysical properties were examined in solution and in the solid state by UV–Vis and fluorescence spectroscopies. Density functional theory (DFT) calculations with ethanol as solvent reproduced reasonably well the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) of the title compound. Hirshfeld surface and fingerprint plot analyses are presented to illustrate the supramolecular connectivity in the solid state.


2017 ◽  
Vol 4 (3) ◽  
pp. 426-436 ◽  
Author(s):  
Jia Tian ◽  
Hui Wang ◽  
Dan-Wei Zhang ◽  
Yi Liu ◽  
Zhan-Ting Li

Abstract Studies on periodic porosity and related properties and functions have been limited to insoluble solid-state materials. Self-assembly provides a straightforward and efficient strategy for the construction of soluble periodic porous supramolecular organic frameworks (SOFs) in water from rationally designed molecular building blocks. From rigid tri- and tetra-armed building blocks and cucurbitu[8]ril (CB[8]), a number of two-dimensional (2D) honeycomb, square and rhombic SOFs can be generated, which is driven by CB[8]-encapsulation-enhanced dimerization of two aromatic units on the periphery of the multi-armed molecules. By utilizing the same three-component host−guest motif as the driving force, three-dimensional (3D) diamondoid and cubic SOFs can be obtained from tetrahedral and [Ru(bipy)3]2+-derived octahedral monomers and CB[8]. All of the 2D and 3D periodic frameworks are soluble in water, and are able to maintain the periodicity as well as the pore sizes in the solid state. 3D SOFs are highly efficient homogeneous polycationic frameworks for reversible adsorption of anionic species including organic dyes, peptides, nucleic acids, drugs, dendrimers and Wells-Dawson-typed polyoxametallates (WD-POMs). WD-POM molecules adsorbed in the [Ru(bipy)3]2+-based SOF can catalyse the reduction of proton to H2 upon visible-light sensitization of [Ru(bipy)3]2+, which allows multiple electron transfer from [Ru(bipy)3]2+ to WD-POM. This review summarizes the design, formation and characterization of this new family of self-assembled frameworks, highlights their applications as homogeneous porous materials and finally outlines some future research directions.


Crystals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 19 ◽  
Author(s):  
Yaping Tao ◽  
Ligang Han ◽  
Andong Sun ◽  
Kexi Sun ◽  
Qian Zhang ◽  
...  

Methyl-3-aminothiophene-2-carboxylate (matc) is a key intermediate in organic synthesis, medicine, dyes, and pesticides. Single crystal X-ray diffraction analysis reveals that matc crystallizes in the monoclinic crystal system P21/c space group. Three matc molecules in the symmetric unit are crystallographically different and further linked through the N–H⋯O and N–H⋯N hydrogen bond interactions along with weak C–H⋯S and C–H⋯Cg interactions, which is verified by the three-dimensional Hirshfeld surface, two-dimensional fingerprint plot, and reduced density gradient (RDG) analysis. The interaction energies within crystal packing are visualized through dispersion, electrostatic, and total energies using three-dimensional energy-framework analyses. The dispersion energy dominates in crystal packing. To better understand the properties of matc, electrostatic potential (ESP) and frontier molecular orbitals (FMO) were also calculated and discussed. Experimental and calculation results suggested that amino and carboxyl groups can participate in various inter- and intra-interactions.


2014 ◽  
Vol 1663 ◽  
Author(s):  
Garima Thakur ◽  
Kovur Prashanthi ◽  
Thomas Thundat

ABSTRACTSelf–assembly of molecular building blocks provides an interesting route to produce well-defined chemical structures. Tailoring the functionalities on the building blocks and controlling the time of self-assembly could control the properties as well as the structure of the resultant patterns. Spontaneous self-assembly of biomolecules can generate bio-interfaces for myriad of potential applications. Here we report self-assembled patterning of human serum albumin (HSA) protein in to ring structures on a polyethylene glycol (PEG) modified gold surface. The structure of the self-assembled protein molecules and kinetics of structure formation entirely revolved around controlling the nucleation of the base layer. The formation of different sizes of ring patterns is attributed to growth conditions of the PEG islands for bio-conjugation. These assemblies might be beneficial in forming structurally ordered architectures of active proteins such as HSA or other globular proteins.


2019 ◽  
Vol 75 (4) ◽  
pp. 451-461 ◽  
Author(s):  
Avantika Hasija ◽  
Deepak Chopra

The concomitant occurrence of dimorphs of diphenyl (3,4-difluorophenyl)phosphoramidate, C18H14F2NO3P, was observed via a solution-mediated crystallization process with variation in the symmetry-free molecules (Z′). The existence of two forms, i.e. Form I (block, Z′ = 1) and Form II (needle, Z′ = 2), was characterized by single-crystal X-ray diffraction, differential scanning calorimetry and powder X-ray diffraction. Furthermore, a quantitative analysis of the energetics of the different intermolecular interactions was carried out via the energy decomposition method (PIXEL), which corroborates with inputs from the energy framework and looks at the topology of the various intermolecular interactions present in both forms. The unequivocally distinguished contribution of strong N—H...O hydrogen bonds along with other interactions, such as C—H...O, C—H...F, π–π and C—H...π, mapped on the Hirshfeld surface is depicted by two-dimensional fingerprint plots. Apart from the major electrostatic contribution from N—H...O hydrogen bonds, the crystal structures are stabilized by contributions from the dispersion energy. The closely related melting points and opposite trends in the calculated lattice energies are interesting to investigate with respect to the thermodynamic stability of the observed dimorphs. The significant variation in the torsion angles in both forms helps in classifying them in the category of conformational polymorphs.


1986 ◽  
Vol 73 ◽  
Author(s):  
W. G. Klemperer ◽  
V. V. Mainz ◽  
D. M. Millar

ABSTRACTA solid state multinuclear NMR study of the sol-gel process was performed using the molecular building blocks tetramethoxysilane, hexamethoxydisiloxane, octamethoxytrisiloxane and octamethoxyoctasilsesquioxane as precursor monomers. Water content, solvent content, and hydrolysis/condensation processes were monitored using 17O, 13C, and 29Si FT, FTMAS and CPMAS NMR techniques.


2020 ◽  
Vol 16 ◽  
Author(s):  
Ilma Nugrahani

: Every "entity" or compound has physical and chemical properties as references for the synthesis and determination of the entity's structure. Thermodynamically, solid-state is the most stable matter in the universe and to be the ideal form in structure elucidation of pharmaceutical. The dry treatments become popular, such as mechanochemistry, microwave heating, and the using of deep eutectic agent. These techniques are viewed as the futuristic methods for reducing environmental damage, in line with "green pharmacy" concept. On the other hand, solid-state analysis methods from the simplest to the most sophisticated one have been used in the long decades, but most are for qualitative purposes. Recently many reports have proven that solid-state analysis instruments are reliable and prospective for implementing in the quantitative measurement. Infrared spectroscopy, powder x-ray diffraction, and differential scanning calorimetry have been employed in various kinetics and content determination studies. A revolutionary method developed for structural elucidation is single-crystal diffraction, which is capable of rapidly and accurately determining a three-dimensional chemical structure. Hereby it shown that the accurate, precise, economical, ease, rapid-speed, and reliability of solid-state analysis method are eco-benefits by reducing the reagent, catalyst, and organic solvent.


Author(s):  
Chenxing Guo ◽  
Vincent M. Lynch ◽  
Jonathan L. Sessler

We report here the synthesis and structural characterization of a novel expanded Schiff base oligopyrrolic macrocycle TxLH (i.e. compound 2) along with its smaller congener hemi-TxLH (i.e. compound 1). The solid-state structure of TxLH is reminiscent of the shape of a Texas Longhorn[Formula: see text]. It thus defines a new architectural form for porphyrin analogues. The present study thus underscores the potential of using functionalized oligopyrroles as readily accessible molecular building blocks for the construction of structurally non-trivial molecules.


2018 ◽  
Vol 74 (4) ◽  
pp. 424-427
Author(s):  
Muhammad Arif Kassim ◽  
Ubaidullah H. M. Yassin ◽  
Ai Ling Tan ◽  
Anwar Usman ◽  
Malai Haniti S. A. Hamid

Hydrazones and their derivatives are closely related to imine compounds and are potential antimicrobial agents. They have also found application in supramolecular chemistry as multitopic ligands to link multiple metal centres for the design of hybrid molecular frameworks. The molecule of the title compound, C6H8N4, consists of an imine linkage with an N—N bond length of 1.3540 (14) Å. This asymmetric compound is nearly planar and adopts an E configuration about the azomethine C=N double bond. In the solid state, there are two intermolecular N—H...N interactions that interconnect the molecules into a two-dimensional network. The three-dimensional arrangement of the crystal packing is further stabilized by intermolecular π–π interactions interconnecting the centroids of the heterocyclic rings.


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