Dimethylformamide Molecules Research Articles

Strengthen Water O-H Bond in Electrolytes for Enhanced Reversibility and Safety in Aqueous Aluminum Ion Batteries.

Aqueous aluminum-ion batteries present a promising prospect for large-scale energy storage applications, owing to the abundance, inherent safety, and the high theoretical capacity of aluminum. However, their voltage output and energy density are significantly hindered by challenges such as complex hydrogen evolution and uncontrollable solvation reactions. In this work, we demonstrate that water decomposition is restrain by increasing the electron density of water protons and increasing the dissociation energy of H2O through robust dipole interactions with highly polar dimethylformamide (DMF) molecules. Moreover, the incorporation of dimethyl methylphosphonate (DMMP) flame retardant effectively addresses the flammability risk arising from a substantial presence of organic additives The in-depth study with experimental and theoretical simulations reveals that the water-poor solvation structure with reduced water activity is achieved, which can (i) effectively mitigate undesired solvated H2O-mediated side reactions on the Al anode; (ii) boost the de-solvation kinetics of Al3+ while preventing cathode structural distortion; (iii) reduce the flammability of hybrid electrolytes. As a proof of concept, the Al//AlxMnO2 full cell employing a hybrid electrolyte demonstrate enhanced stability (deliver 335 mAh g-1 while retaining 71% capacity for 400 cycles) compared to those with pure electrolyte.

Synthesis, X-ray and antibacterial activity of new copper(II) thiosemicarbazone complexes derived from 4-formyl-3-hydroxy-2-naphthoic acid

New thiosemicarbazone ligand derived from 4-formyl-3-hydroxy-2-naphthoic acid (H3L·CH3OH (1)) and their two copper(II) complexes with composition [Cu(H2L)Cl]2.2(dmf) (2), [Cu(H2L)NO3(dmf)] (3) were synthesized and characterized by thermal analysis, IR-, EPR- spectroscopy and single X-ray diffraction method. In both complexes the mono-deprotonated ligand coordinate tridentate to Cu(II) ion by ONS donor atoms provided by phenolic oxygen, azomethine nitrogen and thiol sulfur. In 2 binuclear complex has the square–planar environment of one copper(II) completed by Cl- anion, while a tetragonal pyramid of other metal is formed by Cl- anion and S atom from the neighboring organic ligand. The copper ion in the mononuclear complex 3 adopt a square-pyramidal structure, where the coordination number of copper(II) ion is adjusted to 5 by O atoms of NO3− anion and dimethylformamide molecule. Magnetic investigations of complex 2 revealed the presence of noticeable magnetic couplings between Cu(II) ions, while compound 3 shows the behavior typical of magnetically isolated Cu(II) centers. The compounds tested against St. aureus, C. albicans, E. coli and Kl. Pneumonia were found to be more active against gram-positive bacteria strains.

An oxo‐acetato‐bridged trinuclear cobalt(III) cluster‐persuaded cobalt oxide active electrocatalyst for efficient hydrogen evolution activity

This study presents the synthesis and electrocatalytic performance of the cobalt(III) complex [Co3(μ1,1,1‐O)(μ1,3‐CH3CO2)(L)3]2(DMF)3 (Cotri), featuring a double deprotonated (N,O)‐donor ligand (L2‐), where the protonated form of it (H2L) is 2,2′‐(hydrazine‐1,2‐diylidenebis(ethan‐1‐yl‐1‐ylidene))diphenol. The X‐ray structure reveals a trinuclear cobalt cluster formed with three cobalt(III) centers interlinking through oxido (μ1,1,1‐O) and acetato (μ1,3‐O2CCH3) bridges in coupling with bis‐congregator‐type chelating ligands. Cotri adopts cobalt centers of octahedral and trigonal bipyramidal coordination geometries and bears a dominant Co(2)…H(DMF) agostic interactions appraised by lattice dimethyl formamide (DMF) molecules. Further, Cotri shows promising heterogeneous electrocatalytic hydrogen evolution activity in 1 M KOH, with an overpotential of 441 mV to achieve 10 mA/cm2 current density. Tafel slope analysis suggests the Volmer–Heyrovsky step as the rate‐determining step. The number of active sites and TOF for Cotri were estimated at 4.010 × 10−8 mol and 0.2467 s−1, respectively, ensuring its excellent hydrogen generation activity. Stability assessments through controlled potential electrolysis (CPE) and cyclic voltammetry (CV) for multiple cycles addressed the transformation of Cotri to Co2O3 nanoparticles, which turned out to be a more active Co2O3 electrocatalyst. The morphology and particle size of the in situ developed Co2O3 active catalyst under the electrochemical conditions attributes to the superior hydrogen evolution activity.

Bis(3-aminobenzenesulfonato-N)-diaqua-bis(N,N’-dimethylformamide-O)-copper(II)

Reaction of 3-aminobenzenesulfonic acid (HL1) with Cu(NO3)2·2.5H2O in H2O/DMF leads to the formation of the new bis(3-aminobenzenesulfonato-κN)-diaqua-bis(dimethylformamide-κO)-copper(II) complex [Cu(L1)2(DMF)2(H2O)2] (1) (HL1 = 3-aminobenzenesulfonic acid and DMF = N,N-dimethylformamide). Single crystal X-ray analysis reveals that the hexacoordinated copper(II) center adopts a distorted octahedral geometry with trans-oriented two 3-aminobenzenesulfonate ligands (L1−), two water and two dimethylformamide (DMF) molecules. Comparison of its crystal structure with that of the known bis(4-aminobenzenesulfonato-κN)diaquabis(dimethylformamide-κO)-copper(II) complex [Cu(L2)2(DMF)2(H2O)2] (2) (HL2 = 4-aminobenzenesulfonic acid) discloses that 1 and 2 are the isomers with an identical empirical formula (C18H30CuN4O10S2) and equal numbers of same coordinated solvents (DMF and water). H-bonded supramolecular structures and their corresponding topological analyses revealed a 2D with 6-connected hxl/Shubnikov plane net (3,6) for 1 and a 3D with 8-connected bcu; 8/4/c1; sqc3 net for 2, which are completely different.

Optimized Pore Nanospace through the Construction of a Cagelike Metal-Organic Framework for CO2/N2 Separation.

The development of metal-organic framework (MOF) adsorbents with a potential molecule sieving effect for CO2 capture and separation from flue gas is of critical importance for reducing the CO2 emissions to the atmosphere yet challenging. Herein, a cagelike MOF with a suitable cage window size falling between CO2 and N2 and the cavity has been constructed to evaluate its CO2/N2 separation performance. It is noteworthy that the introduction of coordinated dimethylamine (DMA) and N,N'-dimethylformamide (DMF) molecules not only significantly reduces the cage window size but also enhances the framework-CO2 interaction via C-H···O hydrogen bonds, as proven by molecular modeling, thus leading to an improved CO2 separation performance. Moreover, transient breakthrough experiments corroborate the efficient CO2/N2 separation, revealing that the introduction of DMA and DMF molecules plays a vital role in the separation of a CO2/N2 gas mixture.

2D MOFs Containing Bis(azabenzimidazole) and Dicarboxylate Moieties for the Efficient Oxygen Evolution Reaction and CO2Sorption

With the rapid advancement of electronic technology, the necessity for efficient electrode materials has been tremendously increasing. With this endeavor, the design of cost-saving, environment-friendly, and stable electrocatalysts from earth-abundant transition elements for water splitting is immensely desired. To this contribution, herein, we have aimed to design two stable Co(II)- and Ni(II)-containing redox-active metal–organic frameworks (Co-MOF and Ni-MOF) with a nitrogen-rich linear bis(azabenzimidazole) ligand and electron-rich dicarboxylic acids and explored the redox-active metal–organic frameworks (MOFs) as efficient heterogeneous catalysts for oxygen evolution reaction (OER) and CO2 sorption studies. The structural analysis of Co-MOF shows that it exhibits a double-walled square grid-type two-dimensional structure, whereas Ni-MOF exhibits a rectangular grid-type two-dimensional layered structure. Further, three-dimensional packing of both MOFs is formed by two-dimensional (2D) metal–ligand coordination layers via N–H···O hydrogen bonding interactions with the imidazole moiety and solvent molecules, resulting in one-dimensional cavities. These cavities have void spaces of 27.6 and 33.2% for Co-MOF and Ni-MOF, respectively, which are occupied by water molecules in Co-MOF and dimethylformamide (DMF) molecules in Ni-MOF. Electrochemical studies of these pristine MOFs infer that both MOFs display efficient OER activity in alkaline solutions. These MOFs demand overpotentials of 470 and 450 mV to generate a current density of 10 mA/cm2, which is nearly equivalent to 10% solar energy conversion efficiency. The 2D layers with nitrogen-rich ligands and oxygen-rich linkers are expected to promote better diffusion of electrons and protons in the course of the electrocatalytic process. The presence of hydrophilic channels further promoted to adsorb considerable amounts of CO2 gas (46 and 15 cm3/g, respectively) at 273 K and 1 bar pressure.

CRYSTAL AND MOLECULAR STRUCTURE OF THE ISLAND TETRANUCLEAR DIOXOMOLYBDENUM(VI) COMPLEX [MoO<sub>2</sub>(<i>L</i><sup>1</sup>)]<sub>4</sub> (H<sub>2</sub><i>L</i><sup>1</sup> IS ACETYLACETONE ISONICOTINOYLHYDRAZONE) WITH LARGE INTRA- AND INTERMOLECULAR CHANNELS

The solvated complex [МоО2(L1)]4dimethylformamide (I) was synthesized. Its structure wasdetermined by X-ray diffraction analysis. The crystal structure is composed of the tetranuclear complexes [МоО2(L1)]4 (Ia) as the structural units lying on crystallographic twofold axes. Both crystallographically independent molybdenum atoms are in a distorted octahedral coordination environment formed by two cis-О(oxo) ligands, two N(L1) atoms of two molecules Ia in trans positions to the О(oxo) ligands, and two О(L1) atoms of one complex molecule in cis positions to О(oxo) and trans to each other. Each (L1)2– ligand is coordinated to two Мо atoms in a tetradentate tridentate-chelating (2О, N) bridging (N) mode. The average bond lengths in complex Iа are as follows: Мо–О(oxo), 1.701 Å; Мо–N(L1), 2.460 (b) and 2.214 Å (c); Мо–О(L1), 1.980 Å. The О(oxo)–МоО–(oxo) bond angle is 105.6°. The ordered dimethylformamide molecule is located in a narrow channel in the structure. The strongly disordered (non-located) solvent molecules (methanol/dimethylformamide/water) occupy wide channels in the structure of I.

Study of structure of nonaqueous reverse micelles with o-nitroaniline and methyl orange as molecular probes: comparison with an aqueous reverse micelles

Abstract Instead of water reversed micelles can also be formed with polar organic solvents possessed with high dielectric constant and very low solubility in oil phase. Nonaqueous reverse micelles or microemulsions represent an interesting microreactors for various reactions, especially for reactions, where reagents can react with water. Study of localization places of molecular probes in organic polar pockets of reverse micelles is topical. The solvatochromic behavior of optical probes ortho-nitroaniline (o-NA) and methyl orange (MO) was studied in nonaqueous reverse micelles on the basis of surfactants sodium bis (2-ethylhexyl) sulfosuccinate (AOT) and polyoxyethylene (4) lauryl ether (C12E4) and polar organic solvents (acetonitrile, dimethylformamide, glacial acetic acid, etc.) insoluble in oil phase hexane. The strength of binding of o-NA and MO to AOT and C12E4 reversed micelles was assesssed via binding constant (K b ) and association degree (α) respectively. Donor, acceptor, or dipole-dipole interactions ability of the solvent to the head groups of surfactant was taken into account in order to explain results obtained with UV–visible spectroscopic method. The binding constants of o-NA with reverse AOT micelles in the presence of various solvents in the pockets of reversed micelles increase in the following row water < glacial acetic acid < acetonitrile < dimethylformamide < dimethyl sulfoxide, but this sequence is reversed when o-NA binds to C12E4 reverse micelles. The high value of the proton donor or acidity parameter in the water molecule (x d = 0.37) determines the weak binding of o-NA to the head AOT groups (K b = 20.8) in case of aqueous reverse micelles. The high value of the dipole parameter in the dimethylformamide molecule (x n = 0.40) promotes its strong interaction with nonionic polyoxyethylene groups of C12E4, which results in low value of binding constant (K b = 26.5) in case of optical probe o-NA and low value of association degree (α = 0.60) using MO as absorption probe. The results of this article will contribute to the improvement of the concept of interfacial processes, viz.: (i) some issues of supramolecular chemistry, (ii) revealing the contribution of parameters of donor, acceptor or dipole-dipole interaction in a polar organic solvent at the surfactant/nonpolar organic solvent interface, and (iii) features of the dissolution of optical probes in non-aqueous reverse micelles.

Robust Carbazole-Based Rare-Earth MOFs: Tunable White-Light Emission for Temperature and DMF Sensing.

Rare-earth metal-organic frameworks (RE-MOFs) are an attractive platform to construct luminescent materials for practical applications in lighting, optoelectronics, and sensing. By adjusting the metal composition in mixed RE-MOFs, one can not only realize tunable emission but also construct ratiometric luminescent sensors. As such, it is highly desirable to prepare robust RE-MOFs that display efficient, multifunctional sensing capability. In this work, we designed and synthesized a series of RE-MOFs that exhibit both excellent thermal and chemical stability due to the incorporation of a bulky tert-butyl group on a new carbazole-based ligand. By rationally tuning the molar ratio of Eu3+/Tb3+/Y3+, a white-light-emitting MOF was developed as an excellent thermal sensor that exhibits a temperature-induced ratiometric luminescence response between 278 and 378 K. After removing the coordinated solvent molecules via thermal treatment, the desolvated MOF materials exhibit excellent turn-on or color change sensitivity to recognize dimethylformamide (DMF) molecules. Such high sensitivity is attributed to the DMF coordination that induces the framework structure change and shifts the ligand's excited-state energy level to facilitate the ligand-to-metal energy transfer process. Taking together, NPF-700-RE represents a new class of robust, tunable luminescent materials that have great potential in white-light emission and thermal- and DMF-sensing applications.

Poly[bis-(μ2-N,N-di-methyl-formamide-κ2 O:O)bis-(μ4-thio-phene-2,5-di-carboxyl-ato-κ4 O:O':O'':O''')dicobalt(II)

The asymmetric unit of the title three-dimensional metal-organic hybrid compound, [Co2(C6H2O4S)2(C3H7NO)2] n , comprises two cobalt(II) cations, one residing on a twofold axis and the other on a centre of inversion, one thio-phene-2,5-di-carboxyl-ate (tdc2-) ligand and one coordinating di-methyl-formamide (DMF) solvent mol-ecule. Both of the cobalt(II) cations exhibit an octa-hedral coordination environment from the four carboxyl O atoms of the tdc2- anions in a μ 4-κ 1:κ 1:κ 1:κ 1 fashion and two O atoms from DMF. A pair of carboxyl O atoms and one DMF molecule connect the adjacent cobalt(II) cations into an infinite chain, leading to a rod-spacer framework with rhombus-window channels, yet no residual solvent-accessible voids are present because the coordinating DMF molecules are oriented into the potential channels.

Crystal structure and Hirshfeld surface analysis of 2-(4-amino-6-phenyl-1,2,5,6-tetra-hydro-1,3,5-triazin-2-yl-idene)malono-nitrile di-methyl-formamide hemisolvate.

The title compound, 2C12H10N6·C3H7NO, crystallizes as a racemate in the monoclinic P21/c space group with two independent mol-ecules (I and II) and one di-methyl-formamide solvent mol-ecule in the asymmetric unit. Both mol-ecules (I and II) have chiral centers at the carbon atoms where the triazine rings of mol-ecules I and II are attached to the phenyl ring. In the crystal, mol-ecules I and II are linked by inter-molecular N-H⋯N, N-H⋯O and C-H⋯N hydrogen bonds through the solvent di-methyl-formamide mol-ecule into layers parallel to (001). In addition, C-H⋯π inter-actions also connect adjacent mol-ecules into layers parallel to (001). The stability of the mol-ecular packing is ensured by van der Waals inter-actions between the layers. The Hirshfeld surface analysis indicates that N⋯H/H⋯N (38.3% for I; 35.0% for II), H⋯H (28.2% for I; 27.0% for II) and C⋯H/H⋯C (23.4% for I; 26.3% for II) inter-actions are the most significant contributors to the crystal packing.

Synthesis, Structure, and Thermal Stability of a Mesoporous Titanium(III) Amine-Containing MOF.

The first mesoporous bimetallic TiIII/Al metal-organic framework (MOF) containing amine functionalities on its linkers has been selectively obtained by converting the cheap commercially available (TiCl3)3AlCl3 into Ti3-xAlxCl3(THF)3 and reacting this complex with 2-aminoterephthalic acid in dimethylformamide (DMF) under soft solvothermal conditions. This compound is structurally related to the previously described NH2-MIL-101(M) (M = Cr, Al, and Fe) MOFs. Thermal gravimetric analyses and in situ powder X-ray diffraction (PXRD) measurements demonstrated that this highly air-sensitive TiIII-containing MOF is structurally stable up to 200 °C. Nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, and inductively coupled plasma (ICP) revealed that NH2-MIL-101(TiIII) contains trinuclear Ti3(μ3-O)Cl(DMF)2(RCOO)6 clusters with strongly bound DMF molecules and a small amount of aluminum. Sorption experiments revealed a higher affinity of this MOF for hydrogen compared to the previously described monometallic unfunctionalized MIL-101(TiIII) MOF.

A highly stable terbium(III) metal-organic framework MOF-76(Tb) for hydrogen storage and humidity sensing.

The present study described the synthesis and characterization of MOF-76(Tb) for hydrogen storage and humidity sensing applications. The structure and morphology of as-synthesized material were studied using powder X-ray diffraction, scanning, and transmission electron microscopy. The crystal structure of MOF-76(Tb) consists of terbium(III) and benzene-1,3,5-tricarboxylate(-III) ions, one coordinated aqua ligand and one crystallization N,N´-dimethylformamide molecule. The polymeric framework of MOF-76(Tb) contains 1D sinusoidally shaped channels with sizes of 6.6 × 6.6 Å propagating along c crystallographic axis. The thermogravimetric analysis of the prepared material exhibited thermal stability up to 600 °C. At 77 K and pressure up to 20 bar; 0.6 wt.% hydrogen storage capacity for MOF-76(Tb) was observed. Finally, the humidity sensing measurements (water adsorption experiments) were performed, and the results indicate that MOF-76(Tb) is not a suitable material for moisture sensing applications.

Preparation and characterization of a new chiral metal-organic framework with spiranes

Herein we report the first homochiral IRMOF structure with chiral carbocyclic spirolinkers, basic Zn-(R)-spiro[3.3]heptane-2,6-dicarboxylate, named WIG-5. First, (R)-spiro[3.3]heptane-2,6-dicarboxylic acid was prepared involving a HPLC separation on chiral stationary phase, then further transformed into homochiral WIG-5 by the solvothermal reaction with zinc nitrate hexahydrate in dimethyl formamide (DMF). WIG-5 crystallizes in the P212121 space group and is built of two interpenetrated networks with pcu underlying network topology. The tetranuclear secondary building units (SBUs) of WIG-5 are coordinated to two DMF molecules and six (R)-spiro[3.3]heptane-2,6-dicarboxylic acid linkers, that results in the formation of a homochiral distorted MOF-5-like structure. Extensive characterization by single crystal X-ray diffraction, powder X-ray diffraction, polarized light microscopy, infrared microspectroscopy, solid-state vibrational circular dichroism spectroscopy and thermogravimetry/mass spectroscopy has been performed on the new material. Birefringence of large WIG-5 single crystals enables potential optical applications.

Raman spectra and non-empirical calculations of dimethylformamide molecular clusters structure

The article presents the results of a study on the formation of molecular clusters of dimethylformamide. The intermolecular interactions of isolated molecular clusters have been simulated by B3LYP/(6-31G++(d,p) method. It is shown that hydrogen bonding and resonant transfer of vibrational energy play an important role in the formation of molecular clusters by dimethylformamide molecules. Methyl and aldehyde groups of a DMF molecule act as proton donors in the formation of molecular clusters, CO is a strong acceptor. It was shown that in solutions of DMF with water, an H-bond is formed between the oxygen of NCOH group and the hydrogen atom of water.

New Coordination Polymers of Selected Lanthanides with 1,2-Phenylenediacetate Linker: Structures, Thermal and Luminescence Properties

Solvothermal reactions of lanthanide (III) salts with 1,2-phenylenediacetic acid in N,N′-dimethylformamide (DMF) solvent lead to the formation of the metal complexes of the general formula Ln2(1,2-pda)3(DMF)2, where Ln(III) = Pr(1), Sm(2), Eu(3), Tb(4), Dy(5), and Er(6), 1,2-pda = [C6H4(CH2COO)2]2−. The compounds were characterized by elemental analysis, powder and single-crystal X-ray diffraction methods, thermal analysis methods (TG-DSC and TG-FTIR), infrared and luminescence spectroscopy. They exhibit structural similarity in the two groups (Pr, Sm, and Eu; Tb, Dy, and Er), which was reflected in their thermal behaviours and spectroscopic properties. Single-crystal X-ray diffraction studies reveal that Sm(2) and Eu(3) complexes form 2D coordination polymers with four crystallographically independent metal centers. Every second lanthanide ion is additionally coordinated by two DMF molecules. The 1,2-phenylenediacetate linker shows different denticity being: penta- and hexadentate while carboxylate groups exhibit bidentate-bridging, bidentate-chelating, and three-dentate bridging-chelating modes. The infrared spectra reflect divergence between these two groups of complexes. The complexes of lighter lanthanides contain in the structure coordinated DMF molecules, while in the structures of heavier complexes, DMF molecules appear in the inner and outer coordination sphere. Both carboxylate groups are deprotonated and engaged in the coordination of metal centers but in different ways in such groups of complexes. In the groups, the thermal decomposition of the isostructural complexes occurs similarly. Pyrolysis of complexes takes place with the formation of such gaseous products as DMF, carbon oxides, ortho-xylene, ethers, water, carboxylic acids, and esters. The complexes of Eu and Tb exhibit characteristic luminescence in the VIS region, while the erbium complex emits NIR wavelength.

Exploring the Slow Magnetic Relaxation of a Family of Photoluminescent 3D Lanthanide–Organic Frameworks Based on Dicarboxylate Ligands

A family of metal–organic frameworks with general formula {[Nd2(ant)2((NH2)2-bdc)(DMF)4]·2DMF}n (1) and {[Ln2(ant)2((NH2)2-bdc)(DMF)4]·2DMF·2H2O}n (Ln = Tb (2), Ho (3), and Er (4)) has been obtained from reactions between 9,10-anthracenedicarboxylic (H2ant) and 2,5-diaminoterephthalic ((NH2)2-H2bdc) acids, and lanthanide ions in dimethylformamide (DMF). These lanthanide–organic frameworks (LnOFs) have been characterized, and their crystal structures have been elucidated by single crystal and powder X-ray diffraction methods (on the basis of a comparative refinement with similar structures), respectively for 1 and 2–4. All LnOFs present three-dimensional structures composed of dinuclear [Ln2(µ-CO2)4] entities linked through both carboxylate ligands that yield open frameworks in which DMF and water molecules are located in the channels. Magnetic studies of these LnOFs have revealed slow relaxation of the magnetization for the Nd-based counterpart. The compounds also acknowledge relevant photoluminescence (PL) emissions in the visible (for the Tb-based homologue) and near-infrared (for the Nd- and Er-based compounds) regions. The strong green emission yielded by compound 2 at room temperature allows its study for photoluminescence (PL) sensing of various solvent molecules, finding a particular discrimination for acetone.

Pockets and channels in tennimide solvate structures: Influence of solvent on crystal packing behaviour

Four solvates of the imide-based macrocycle (IO)4 are reported herein as the acetone, ethanol, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) crystal structures (where I and O represent the isophthaloyl group and imide linker, respectively). The acetone solvate (1) or (IO)4•0.375(CH3COCH3) contains an acetone molecule residing on a 2-fold axis with 0.75 site occupancy in the monoclinic space group C2/c. Acetone is encapsulated in lattice pockets between six (IO)4 macrocycles, four of which are at hydrogen bonding distances. The isomorphous hemi-ethanol solvate structure (2) or (IO)4•0.5(C2H5OH) has ethanol molecules disordered about 2-fold axes and each is effectively surrounded by six (IO)4 macrocycles. The DMF solvate structure (3) in the monoclinic space group P21/n contains two DMF molecules, one of which is disordered and present with a minor component of H2O. In contrast to solvent behaviour in (1) and (2), DMF molecules aggregate in 1D channels parallel with the (-101) plane in the (IO)4•2(DMF)•0.1(H2O) structure with DMF occupying ~20% of the unit cell volume. The DMSO crystal structure (4) was obtained from poorly formed, striated and cracked crystals in the monoclinic space group C2. It contains DMSO molecules with extensive disorder and with partial occupancy solvent molecules of indeterminate composition aligned in channels between (IO)4 macrocycles. Analysis of the development of imide-based macrocycles with different substituents is commented on as well as the solvatomorphic behaviour in tennimides, together with comparisons with ab initio calculations.

Effect of N,N′-dimethylformamide solvent on structure and thermal properties of lanthanide(III) complexes with flexible biphenyl-4,4′-dioxydiacetic acid

The N,N′-dimethylformamide (DMF) was used in the microwave-assisted (MW) solvothermal method for the preparation of lanthanide(III) complexes with biphenyl-4,4′-dioxydiacetic acid (H2L) of the formula Ln2L3·xDMF⋅yH2O where Ln = lanthanide(III) ions from La(III) to Lu(III) with the Pm(III) exception x = 1.5–3; y = 2 for Yb and Lu or 0 for the remaining complexes and L = C14H12O2(COO) 2 2− . The obtained complexes were characterized by the elemental analysis, infrared spectroscopy (ATR-FTIR), X-ray diffraction patterns and different methods (TG-DSC and TG-FTIR) of thermal analysis. Crystalline complexes contain N,N′-dimethylformamide molecules in their structures. Additionally, water molecules are present in the structures of Yb(III) and Lu(III) complexes. Coordination of lanthanide ions occurs through carboxylate oxygen atoms from the biphenyl-4,4′-dioxydiacetate ligand and most probably carbonyl oxygen atom from N,N′-dimethylformamide. The investigated compounds exhibit different thermal stability, and removal of solvent molecules takes place in a more complex way in the group of heavy lanthanide complexes. Their desolvated forms are an unstable [except Yb(Lu)2L3 compounds], and their further heating leads to the formation of suitable lanthanide oxides (air atmosphere). Thermal stability of the investigated compounds is higher in nitrogen atmosphere. The TG-FTIR methods allowed to propose way of thermal decomposition of investigated compounds through identification of volatile products such as: DMF, H2O, CO2, CO and CH4 evolved during heating of complexes. The luminescent properties of terbium(III) and europium(III) complexes were also investigated.

Structure of a potassium salt of Lasalocid A and an investigation of solid–state conformational variance of the Lasalocid A backbone in known complexes

The structure of a potassium salt of the polyether ionophore antibiotic Lasalocid A has been determined by single–crystal X–ray crystallography. A dimeric structure is revealed in which two antibiotic molecules present hemispheric oxygen co–ordination environments for two potassium centres. Co–ordination for both cations is further fulfilled by contact with the oxygen atoms of two discrete dimethylformamide molecules that bridge the two potassium centres. Close analysis using directional statistics of the conformation of the backbone of the Lasalocid A molecule in all previously reported crystal structures, as well as the potassium salt reported here, reveals that conformation is substantially conserved throughout the series, aside from some variation in the twist of the carboxylate group with respect to the plane of the aromatic ring, and the orientation of the tetrahydrofuran ring. The Lasalocid A molecule in the potassium complex presented here is the closest fit to the averaged Lasalocid structure, derived from the family of known complexes,