Weak Intermolecular Interactions Research Articles

Adhesive Zwitterionic Poly(ionic liquid) with unprecedented Organic Solvent Resistance.

The resistance of adhesives to organic solvents is of paramount importance in diverse industries. Unfortunately, many currently available adhesives exhibit either weak intermolecular chain interactions, resulting in insufficient resistance to organic solvents, or possess a permanent covalent crosslinked network, impeding recyclability. This study introduces an innovative approach to address this challenge by formulating zwitterionic poly(ionic liquid) (ZPIL) derivatives with robust dipole-dipole interactions, incorporating sulfonic anions and imidazolium cations. Due to its unique dynamic and electrostatic self-crosslinking structure, the ZPIL exhibits significant adhesion to various substrates and demonstrates excellent recyclability even after multiple adhesion tests. Significantly, ZPIL exhibits exceptional adhesion stability across diverse non-polar and polar organic solvents, including ionic liquids, distinguishing itself from non-ionic polymers and conventional poly(ionic liquid)s. Its adhesive performance remains minimally affected even after prolonged exposure to soaking conditions. The study presents a promising solution for the design of highly organic solvent-resistant materials for plastics, coatings, and adhesives. This article is protected by copyright. All rights reserved.

Exfoliatable Layered 2D Honeycomb Crystals of Host-guest Complexes Networked by CH-π Hydrogen Bonds.

Studies of graphene show that robust chemical bonds such as covalent bonds with trigonal-planar atoms afford layered atomic 2D crystals possessing unique properties. Although layered molecular crystals are of interest to diversify elements and structures of 2D materials, the structural diversity of molecules as well as weak intermolecular interactions inevitably makes the design to be one-off and individual. We herein report a versatile method to assemble layered molecular crystals. By developing a D3-symmetry host at vertices to form a honeycomb layer, a diverse range of layered 2D host-guest crystals were obtained. Substituents on the host, elements/structures of the guest, stereochemistries of the host and types of intercalants were diversified, which should allow for 6×32×3×2 combinations for structural diversification.

Supramolecular Entanglement in a Hydrogen‐Bonded Organic Framework Enables Flexible‐Robust Porosity for Highly Efficient Purification of Natural Gas

AbstractThe development of porous materials with flexible‐robust characteristics shows some unique advantages to target high performance for gas separation, but remains a daunting challenge to achieve so far. Herein, we report a carboxyl‐based hydrogen‐bonded organic framework (ZJU‐HOF‐8a) with flexible‐robust porosity for efficient purification of natural gas. ZJU‐HOF‐8a features a four‐fold interpenetrated structure with dia topology, wherein abundant supramolecular entanglements are formed between the adjacent subnetworks through weak intermolecular hydrogen bonds. This structural configuration could not only stabilize the whole framework to establish the permanent porosity, but also enable the framework to show some flexibility due to its weak intermolecular interactions (so‐called flexible‐robust framework). The flexible‐robust porosity of ZJU‐HOF‐8a was exclusively confirmed by gas sorption isotherms and single‐crystal X‐ray diffraction studies, showing that the flexible pore pockets can be opened by C3H8 and n‐C4H10 molecules rather by C2H6 and CH4. This leads to notably higher C3H8 and n‐C4H10 uptakes with enhanced selectivities than C2H6 over CH4 under ambient conditions, affording one of the highest n‐C4H10/CH4 selectivities. The gas‐loaded single‐crystal structures coupled with theoretical simulations reveal that the loading of n‐C4H10 can induce an obvious framework expansion along with pore pocket opening to improve n‐C4H10 uptake and selectivity, while not for C2H6 adsorption. This work suggests an effective strategy of designing flexible‐robust HOFs for improving gas separation properties.

Orchestrated Octuple C-H Activation: A Bottom-Up Topology Engineering Approach toward Stimuli-Responsive Double-Heptagon-Embedded Wavy Polycyclic Heteroaromatics.

Curiosity-driven innovations on the design and synthesis of nonplanar polycyclic aromatic/heteroaromatic compounds with new molecular topologies unfold exciting opportunities for harnessing their intriguing supramolecular properties and thereby the development of novel functional organic materials. This work presents such an innovative synthetic concept of a bottom-up molecular topology engineering through a unique orchestrated octuple C-H activation reaction, toward the rapid synthesis of a novel class of double heptagon-incorporated nitrogen-doped laterally-fused polycyclic compounds with rarely reported wavy structural configuration. The profound impact of the molecular wavy structures of these compounds on their properties is manifested by weak and tunable solid-state intermolecular interactions controlling the electronic properties of the materials, leading to reversibly switchable fluorochromism in the solid state and thin films with mechanical force and solvent vapors as external stimuli, thereby indicating their potential applicability in rewritable fluorescent optical recording media, security papers, mechanosensors, volatile organic compound (VOC) sensors etc.

Evolution of structure and spectroscopic properties of a new 1,3-diacetylpyrene polymorph with temperature and pressure.

A new polymorph of 1,3-diacetylpyrene has been obtained from its melt and thoroughly characterized using single-crystal X-ray diffraction, steady-state UV-Vis spectroscopy and periodic density functional theory calculations. Experimental studies covered the temperature range from 90 to 390 K and the pressure range from atmospheric to 4.08 GPa. Optimal sample placement in a diamond anvil cell according to our previously presented methodology ensured over 80% data coverage up to 0.8 Å for a monoclinic sample. Unrestrained Hirshfeld atom refinement of the high-pressure crystal structures was successful and anharmonic behavior of carbonyl oxygen atoms was observed. Unlike the previously characterized polymorph, the structure of 2°AP-β is based on infinite π-stacks of antiparallel 2°AP molecules. 2°AP-β displays piezochromism and piezofluorochromism which are directly related to the variation in interplanar distances within the π-stacking. The importance of weak intermolecular interactions is reflected in the substantial negative thermal expansion coefficient of -55.8 (57) MK-1 in the direction of C-H...O interactions.

Organic Electrode Materials for Energy Storage and Conversion: Mechanism, Characteristics, and Applications.

ConspectusLithium ion batteries (LIBs) with inorganic intercalation compounds as electrode active materials have become an indispensable part of human life. However, the rapid increase in their annual production raises concerns about limited mineral reserves and related environmental issues. Therefore, organic electrode materials (OEMs) for rechargeable batteries have once again come into the focus of researchers because of their design flexibility, sustainability, and environmental compatibility. Compared with conventional inorganic cathode materials for Li ion batteries, OEMs possess some unique characteristics including flexible molecular structure, weak intermolecular interaction, being highly soluble in electrolytes, and moderate electrochemical potentials. These unique characteristics make OEMs suitable for applications in multivalent ion batteries, low-temperature batteries, redox flow batteries, and decoupled water electrolysis. Specifically, the flexible molecular structure and weak intermolecular interaction of OEMs make multivalent ions easily accessible to the redox sites of OEMs and facilitate the desolvation process on the redox site, thus improving the low-temperature performance, while the highly soluble nature enables OEMs as redox couples for aqueous redox flow batteries. Finally, the moderate electrochemical potential and reversible proton storage and release of OEMs make them suitable as redox mediators for water electrolysis. Over the past ten years, although various new OEMs have been developed for Li-organic batteries, Na-organic batteries, Zn-organic batteries, and other battery systems, batteries with OEMs still face many challenges, such as poor cycle stability, inferior energy density, and limited rate capability. Therefore, previous reviews of OEMs mainly focused on organic molecular design for organic batteries or strategies to improve the electrochemical performance of OEMs. A comprehensive review to explore the characteristics of OEMs and establish the correlation between these characteristics and their specific application in energy storage and conversion is still lacking.In this Account, we initially provide an overview of the sustainability and environmental friendliness of OEMs for energy storage and conversion. Subsequently, we summarize the charge storage mechanisms of the different types of OEMs. Thereafter, we explore the characteristics of OEMs in comparison with conventional inorganic intercalation compounds including their structural flexibility, high solubility in the electrolyte, and appropriate electrochemical potential in order to establish the correlations between their characteristics and potential applications. Unlike previous reviews that mainly introduce the electrochemical performance progress of different organic batteries, this Account specifically focuses on some exceptional applications of OEMs corresponding to the characteristics of organic electrode materials in energy storage and conversion, as previously published by our groups. These applications include monovalent ion batteries, multivalent ion batteries, low-temperature batteries, redox flow batteries with soluble OEMs, and decoupled water electrolysis employing organic electrodes as redox mediators. We hope that this Account will make an invaluable contribution to the development of organic electrode materials for next-generation batteries and help to unlock a world of potential energy storage applications.

Dynamic physical network constructed by tripartite H-bonds in artificial SEI to shape ultra-long life dendrite-free lithium-metal anodes

Constructing artificial solid electrolyte interfaces (SEIs) to shape dendrite-free lithium (Li)-metal anodes remains challenges. Herein, we designed dynamic physical network (DPN) with abundant lithiophilic/anionphilic groups through tripartite hydrogen bonds (H-bonds), serving as artificial SEIs in high-loading NCM811-Li metal batteries. The formation and dissociation of DPN endowed by tripartite H-bonds under tension release during Li plating/stripping cycling skillfully balance the contradiction between mechanical robustness and deformability. LiO bonds between lithiophilic sites and Li ions, and extra H-bonds between hydroxyl and electrolyte anions, endow DPN with functions of homogenizing Li-ion flux and accelerating its desolvation, synergistically achieving the uniform Li-ion deposition and weakening the charge shielding. The artificial SEI enhanced Li-anode (DPN@Li) withstood repeated Li ions plating/stripping processes for over 1000 h, which is 5 times longer than pure Li-anodes, and maintained low overpotential at a high current density of 10 mA cm−2. DPN@Li-based NCM811 full cells deliver high specific capacities and outstanding cycle life over 3000 cycles. Further, DPN@Li possesses excellent electrochemical performance in the high active material loading (7.84 mg cm−2) and foldable pouch cells. This work provides a conceptual framework of DPN constructed by multiple weak intermolecular interaction for artificial SEI to shape anode performance, and achieves the idea with a facile manner and simple chemical substances to promote practical applications of LMBs.

Effect of Fatty Acid Unsaturation on the Intermolecular Weak Interaction at the Low-Rank Coal-Water Interface: Density Functional Theory Calculations and Experimental Study.

The study on the effect of fatty acid saturation on low-rank coal (LRC) flotation is still limited. In this investigation, density functional theory (DFT) combined with Zeta potential and Fourier transform infrared spectroscopy (FTIR) was used to study the mechanism of intermolecular weak interaction at the LRC-water interface of fatty acids (decanoic acid (DA), undecylenic acid (UA), and phenyl propionic acid (PA)) with different saturations and different dodecane (D) composition hydrocarbon oil-fatty acid mixed collectors (D-DA, D-UA, D-PA). The findings demonstrated that the hydrogen bond interaction and electrostatic interaction between the UA/PA with unsaturated bonded carbon chains and the LRC molecular fragments/water molecules were stronger than DA without a saturated bond carbon chain, and UA/PA strengthened its interaction with water molecules on the whole, even PA molecules would preferentially interact with water molecules. The unsaturated bond had a minimal impact on the adsorption of the LRC hydrophobic site, and the strength of the hydrogen bond between the mixed collector and LRC is D-DA > D-UA > D-PA. In the actual flotation process, the strong hydrogen bonding and electrostatic interaction between UA/PA and water molecules weaken the collection performance of the mixed collector D-UA/D-PA for LRC, which also confirmed the research results of DFT, FTIR, and Zeta.

Study of the relationship between pressure and sensitivity of energetic materials based on first-principles calculation.

In order to study the relationship between the sensitivity and pressure of energetic materials, six kinds of energetic materials were selected as the research object. The crystal structure, electronic, and phonon properties under hydrostatic pressure of 0 ~ 45 GPa were calculated by first principles. The calculation results show that the lattice parameters and band gap values of these six energetic materials decrease with the increase of pressure. The peak of the density of states decreases and moves to the low energy direction, and the electrons become more active. Meanwhile, the effect of pressure on the sensitivity of the energetic materials is analyzed based on the multi-phonon up-pumping theory. The number of doorway modes and integral of projected phonon density of states under high pressure is calculated. The results show that both of them increase with the increase of pressure. And the smaller the value of the band gap, the larger the number of doorway modes and integral of projected phonon density of states, and the more sensitive the energetic material is. All calculations are performed using the Materials Studio software based on density functional theory. The Perdew-Burke-Ernzerhof (PBE) functional of the generalized gradient approximation (GGA) is used to calculate the exchange correlation function, and the Grimme dispersion correction method is used to deal with the weak intermolecular interaction. The structure of the compound was optimized by BFGS algorithm. The linear response is used to calculate the phonon properties of energetic materials. The plane wave cutoff energy was set to 830eV. The K-point grids of TATB, FOX-7, TNX, RDX, TNT, and HMX were chosen as 2 × 2 × 2, 2 × 2 × 1, 2 × 1 × 1, 1 × 1 × 1, 1 × 2 × 1, and 2 × 1 × 2.

A model of ionization-induced reactions in CH4/N2 clusters in Titan's atmosphere: theoretical insights into mono- and divalent states

Abstract We propose a model for ionization-induced reactions between N2 and CH4, the main components of Titan's atmosphere, and examine their mechanism using quantum mechanical and molecular dynamics methods. Bimolecular CH4–N2 clusters form through collision, and their conformation depends on the encounter cross section due to weak intermolecular interaction. These clusters acquire a driving force through vertical ionization because the vertically ionized structure is not situated at the minimum of the potential energy surface in the ionized state. This leads to multiple reactions, overcoming energy barriers in the process. In the divalent state, a robust attractive interaction occurs between CH4 and N2 through charge transfer. Subsequently, the H4C–N2 covalent bond forms prior to reactions, resulting in the production of N2H+, CH3+, CH3N2+, and CH2N2+; otherwise only N2H+, CH3+, and CH2+ are generated. In contrast, when ionized to a monovalent state, although dissociation of N2H+ and isomerization to CH3NHN+ and CH3NNH+ occurs, a significant portion dissociates into CH4+ and N2 without undergoing further reactions. Additionally, the generation of N2H+ and CH3+ is limited in the monovalent state, primarily due to a lower driving force and the absence of Coulombic explosion. Our computational results highlight the pivotal role of divalent reactions within Titan's atmosphere, which are more efficient than monovalent reactions.

Fluorescence Switching and Photoisomerization of a Spiropyran Molecular Photoswitch through Confined Spaces Regulation in Crystals.

Spiropyran (SP) and its derivatives are highly attractive owing to their distinctive merits in high contrast and fast response read-out systems. However, the realization of photoswitching properties of SP is hindered in the aggregate state, particularly in crystals owing to the dense packing of molecules leading to insufficient study of the relationship between the molecular structure/stacking mode and photoswitching behavior. Herein, we report three SP derivatives: different flexible chains (carboxyl group for SP-0 and ester group for SP-1) are attached to the indoline moiety, while the ester group is attached to the chromene moiety for SP-2. SP-1 exhibits fluorescent photoswitching properties in crystals due to the weak intermolecular interactions resulting in enough free space for the photoisomerization. The presence of hydrogen bonds in SP-0 enhances the molecular interactions to restrict the photoisomerization, and the ester group of SP-2 impacts the thermodynamic properties, thereby limiting the realization of photoswitching of SP-2.

Insight into the interaction between zirconium dibutyl phosphate complex and diluents: An experimental and computational study

In solvent extraction processes, there are challenges caused by the formation of the third phase or interfacial precipitation. The branched alkanes have been used as diluents to disrupt the third-phase formation, while there is little study about the effect of diluents on the appearance of precipitation. Here, we report the inhibiting effect of the novel hyperbranched alkane diluent (HAD) on the formation of zirconium-dibutyl phosphate (Zr-DBP) precipitation and investigate the formation mechanism by the density functional theory (DFT) theory. The extraction experiments show that HAD as the diluent has a remarkable inhibiting ability to form Zr-DBP precipitation, compared with n-dodecane and kerosene. The spectra show no noticeable difference in the composition and structures of the precipitations formed in the three diluents. The energetics from the DFT calculations suggest the P-OH and P=O ligands on one HDBP molecule can bridge two Zr-DBP complexes into a dimer and then aggregate into the precipitation. Besides, the interactions between diluent-diluent molecules play a significant role in precipitation formation. The straight-chain n-dodecanes have a strong intermolecular dispersion force and tend to attract each other but not the Zr-DBP complex. However, the branched alkanes with weak intermolecular interactions have a better dispersive capacity for Zr-DBP complexes, due to the much higher dispersion force of diluent-complex interaction than that of the diluent-diluent interaction. This work provides a new insight into the formation of interfacial crud from the interactions between solutes and diluents of the organic phase in solvent extraction.

Synthesis, structural, multitargeted molecular docking analysis of anti-cancer, anti-tubercular, DNA interactions of benzotriazole based macrocyclic ligand

Biologically important macromolecule 1, 1′, 3, 3′ Bis − [2,3,5,6-Tetramethyl-p-phenylenebis(methylene)] dibenzotriazlinium dibromide hydrate (BTD) was synthesized and characterized using FT-IR, NMR and single-crystal XRD (SCXRD). SCXRD revealed that the compound was crystallized as a monoclinic system and associated through weak intermolecular interactions like H-bonding and π- π stacking interactions. These weak intermolecular interactions in BTD were studied using Crystal Explorer and Gaussian. The calculated energies for the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO) showed the stability and reactivity of the title compound. Molecular electrostatic potential (MEP) surface analysis was used to investigate the crystal’s nucleophilic and electrophilic reactive sites. The molecular shape and intermolecular interactions in the crystal structure were determined using Hirshfeld surface analysis and fingerprint plots. Anticancer, anti-bacterial and DNA binding ability of BTD were investigated by experimental and theoretical techniques. The obtained results suggest that BTD possesses better anti-cancer, anti-bacterial and DNA binding abilities. The mode of action of antibiotic and anticancer approach was discussed. This provides promising therapeutic advantages for further development.

Graphene Oxide‐Assisted Molecular Crystal Co‐Assembly for Large‐Scale Freestanding 2D Photoresponse Heterostructures with Synaptic Plasticity

Abstract2D van der Waals heterostructures (2D vdWHs) have been gaining significant attention in neuromorphic electronics. However, the facile synthesis of large‐scale, high‐quality freestanding 2D vdWHs remains challenge, particularly for organic counterparts due to susceptible nucleation behaviors and weak intermolecular interactions. Here, the study reports a graphene oxide (GO)‐assisted molecular crystal co‐assembly method for one‐step growth of centimeter‐scale freestanding heterostructures. This co‐assembly involves the simultaneous assembling of organic and GO precursors at the liquid–liquid interface, where the amphiphilic nature of GO nanosheets facilitates the diffusion of organic molecules and 2D nucleation of organic crystals, and the nanosheets also become enriched to grow a quasi‐solid film for the bilayer formation. Owing to integrated photosensitive and charge‐trapping properties as well as type II band structure, this heterostructure exhibits exceptional photonic synaptic behaviors, with a paired‐pulse facilitation index of 141% and image recognition of 91%.

Applicability of self-consistent reaction field (SCRF) method to DFT estimation of hydrogen isotope separation factors in reversible processes

ABSTRACT In earlier quantum chemical calculations of isotope effects, chemical species in the liquid phase were generally treated as existing in the gas phase. In recent years, however, advances in computational programs have made it easier for the self-consistent reaction field (SCRF) method to handle chemical species in the liquid phase, and as a result, it has become easier to apply the SCRF method to isotope effect calculations. This paper concerns the scope of application of the DFT-SCRF method to reversible processes for hydrogen isotope enrichment. It is found that the applicability of the method depends on the type of the intermolecular interaction in the liquid phase and the degree of hydrogen isotope effect (separation factor) on which the process is based. When the magnitude of the isotope effect of the separation system is greater than 10–1, the simple SCRF method is fully applicable; when the magnitude is around 10–2, SCRF with a dimer model, in which the monomer is replaced by a dimer, is applicable for the analysis of the liquid phase with relatively strong intermolecular interactions. Anharmonic correction to the separation factor calculated based on harmonic frequencies may be effective to systems with the liquid phase with weak intermolecular interactions.

Origin of Melt Memory Effects in Poly(ethylene oxide): The Crucial Role of Entanglements.

The melt memory effect on crystallization is an intriguing phenomenon displayed by semicrystalline polymers, as opposed to low molar mass molecules. It concerns the effect of melt temperature on nucleation upon recrystallization. Typically, polymer crystals must be considerably superheated to erase the effect of previous morphology on the subsequent crystallization, avoiding an acceleration of the process. Despite being known for decades, its origin is still not fully understood. Investigating model poly(ethylene oxide) covering a wide range of molar mass, it is demonstrated that melt memory originates from topological constraints among the chains, i.e., entanglements, for PEO in which weak intermolecular interactions are present due to the ether groups. In fact, no memory is observed for samples below the critical molar mass for the formation of entanglements (about 1 kg mol-1). The increase in molar mass raises the number of entanglements and induces the formation of folded chains crystals, both factors leading to a topologically complex amorphous phase, enhancing the melt memory effect. The molecular origin of the melt memory effect in polymers with weak intermolecular interactions is thus ascribed to a slower isotropization in the melt of the chain segments originally contained in the crystals, due to the presence of entanglements among the chains. This study defines the distinction between small molecules and polymers from the point of view of melt memory.

Dicyanopyridine derivatives: One-pot preparation, ACQ-to-AIE transformation, light-conversion quality and photostability

Low cost and strong fluorescence emission are two important guarantees for luminogens used as light conversion agents. By one-pot multicomponent approach and inexpensive starting materials, three dicyanopyridine (DP) derivatives named as DCP (2-amino-6-methoxy-4-phenylpyridine-3,5-dicarbonitrile), DCO (2-amino-6-methoxy-4-(4-methoxyphenyl) pyridine-3,5-dicarbonitrile) and DCC (2-amino-4-(4-cyanophenyl)-6-methoxypyridine-3,5-dicarbonitrile) were designed and synthesized.Meanwhile, the ACQ-to-AIE transformation was successfully realized by altering substituent groups rather than traditional rotor–stator theory. Based on crystal analysis and theoretical calculations, the ACQ-to-AIE transformation is attributed to the tunable stacking modes and intermolecular weak interactions. Owing to matched fluorescence emission, low lost, high yield, and AIE activity, DCC is used as light conversion agents and doped in EVA matrix. The light conversion quality confirms that DCC can not only convert ultraviolet light, but also significantly improve the transmittance of 25 %/40 % EVA, whose photosynthetic photon flux density at 400–500 nm and 600–700 nm increased to 30.67 %/30.21 % and 25.37 %/37.82 % of the blank film, respectively. After 20 h of UV irradiation (365 nm, 40 W), the fluorescence intensities of DCC films can maintain 92 % of the initial values, indicating good photostability in the doping films. This work not only provides an excellent and low-cost light conversion agent, but also has important significance for ACQ-to-AIE transformation of luminogens.

Comparing the crystal structures and spectroscopic properties of a p-hydroxy styrylquinolinium dye with those of its p-dimethylamino analogue

Two previously synthesized styrylquinolinium dyes, namely (E)-1-butyl-4-(4-(dimethylamino)styryl)quinolinium iodide (D36) and (E)-1-butyl-4-(4-hydroxystyryl)quinolinium iodide (D34), were compared in terms of their properties by single-crystal X-ray diffraction (XRD), Hirshfeld surface analysis, Fourier transform Raman (FT-Raman), Fourier transform infrared (FT-IR), fluorescence, and ultraviolet–visible (UV–Vis) spectroscopy, and 1H- and 13C-NMR methods. Both dyes D36 and D34 crystallized in the triclinic and monoclinic systems in the centrosymmetric space groups P-1 and P21/n, respectively. The unit cell of D36 contains two molecules of the dye, participating in weak intermolecular interactions, whereas that of D34 contains four formula units. The phenolic hydroxy group of D34 participates in the formation of a hydrogen bond with the iodide anion. The 4-styrylquinolinium moieties of the cationic dye molecules are nearly planar. The dihedral angle between the mean planes through the ten-membered quinolinium system and the benzene ring is 7.5° in D36 and 5.9(1)° in D34. The structural parameters planarity and bond length alternation (BLA) are discussed, which are important for the evaluation of the first hyperpolarizability β at the molecular level, even in a centrosymmetric crystal. The UV–visible spectra of the dyes in 14 solvents of different polarities were investigated. The reversible solvatochromic behavior of the dyes is demonstrated experimentally and compared with known “binuclear dyes” by evaluating the Rezende model. Dye D36 does not fluoresce, and D34 has a very low emission in the solvents tested.

Novel Trinuclear Copper(II) Complex: Crystal Structure at 100 K and Magnetic Properties of (R, S)-di[(6,7-dimethoxy-isoquinolin-1-yl)-(3,4-dimethoxy-phenyl)-methanolato]-tetra(2-hydroxybenzoato)-diaqua-tricopper dihydrate, [Cu3(C7H5O3)4(C20H20NO5)2(H2O)2]·2(H2O)

The crystal structure of [Cu3(C7H5O3)4(C20H20NO5)2(H2O)2]·2(H2O) (1) and analysis of temperature and field dependence of magnetic susceptibility is reported in this work. The structure of 1 is composed of trinuclear complex units and water molecules. The middle copper atom occupies the center of symmetry. N, O-bonded (6,7-dimethoxy-isoquinolin-1-yl)-(3,4-di­methoxy-phenyl)-methanolato ligands, 2-hydroxybenzoates with bridging carboxylic groups, and oxo-bridged water molecules connect the middle Cu(II) atom with the terminal copper atoms. Two 2-hydroxybenzoates coordinate the terminal copper atoms via one carboxylic oxygen and an O atom of the hydroxyl group. The analysis of copper coordination by bond-valence sum approach and relevant structural correlation is consistent with hexacoordinated Cu(II) centers. Cu···Cu separation is 3.0269(3) Å. The magnetism of 1 shows a strong ferromagnetic interaction between the neighboring metallic centers accompanied by very weak antiferromagnetic intermolecular interactions. The complex units are mutually held by π···π stack interactions of 2-hydroxybenzoates and hydrogen bonds.Graphical A new N,O bonded ligands, (R, S)-[(6,7-dimethoxy-isoquinolin-1-yl)-(3,4-dimethoxy-phenyl)-methanolate] coordinate the terminal atoms of the trinuclear copper(II) complex.

Supramolecular architecture of sodium heterocyclic dithiocarbamate salt: Insights from spectral analysis and bond valence sum characterization

The hydrated sodium salt of 1,2,3,4-tetrahydroquinolinedithiocarbamate (1) has been successfully synthesized and characterized using IR, NMR, and X-ray single crystal analysis. The υC–S and thioureide υC–N bands appeared at 1484 cm−1 and 968 cm−1, respectively, in Na(H2O)3+(thqdtc)– • H2O. The notable NCS2 carbon signal emerged at 212 ppm, credited to unique nitrogen and sulfur-induced deshielding effects. Compound 1 crystallizes in the monoclinic system, P21/c space group, with dimensions a = 14.4297(4) Å, b = 6.1534(2) Å, c = 17.6701(4) Å, β = 108.7340(10)°, V = 1485.83(7) Å3, and Z = 4. The structure of 1 exhibits a supramolecular architecture through secondary interactions, such as weak intermolecular interactions that link the molecules into a linear polymeric chain. The incorporation of heterocyclic rings in the dithiocarbamate ligands leads to the formation of an intriguing supramolecular architecture, as confirmed by BVS analysis results. The BVS value of sodium does not agree well with the formal oxidation state due to the interactions of anions, cations, coordinated and uncoordinated water molecules.