CIF Files Research Articles

Photoluminescent Lanthanide(III) Complexes Based on 2-[((4-Chlorophenyl)amino)methylene]-5,5-dimethylcyclohexane-1,3-dione

Five coordination compounds of the general formula [LnL2(NO3)3]n (Ln3+ = Eu (I), Sm (II), Tb(III), Dy (IV), and Gd (V)) are synthesized from 2-[((4-chlorophenyl)amino)methylene]-5,5-dimethylcyclohexane-1,3-dione (L). The crystal structures of the ligand and complex III are determined by X-ray diffraction (XRD) of single crystals (CIF files CCDC nos. 2298715 (L) and 2298716 (III)). Complex III is polymeric due to the bidentate-bridging coordination of the ligand by the oxygen atoms of the cyclohexanedione fragment, and the coordination number of the central atom is ten. According to the phase XRD data, all synthesized polycrystalline compounds are isostructural to the single crystals of complex III. The photoluminescence properties of the ligand and coordination compounds in the polycrystalline state are studied. The energy transfer from the ligand to lanthanide(III) ion is shown to proceed via the “antenna” mechanism in the case of the europium(III), samarium(III), and terbium(III) compounds. Among the series of the complexes, the highest quantum yield is observed for compound I (21.9%), and the sensibilization efficiency of the europium(III) complex is 43.5%.

Potassium, ytterbium(II), and samarium(III) alkoxide complexes containing the <i>tris</i>((2-dimethylaminomethyl)phenyl)methoxide ligand: synthesis and structures

The reaction oftris((2-dimethylaminomethyl)phenyl)methanol ((2-Me2NCH2C6H4)3COH) with potassium hydride in THF at –35°C affords dimeric alkoxide {[(2-Me2NCH2C6H4)3CO]K(THF)}2(I) in a yield of 90%. The reaction of compound I with YbI2(THF)2(1 : 1, 25°C) gives the Yb(II) alkoxyiodide complex {[(2-Me2NCH2C6H4)3CO]Yb(μ-I)(THF)2}2(II) in a yield of 57%. Complex II in the crystalline state is dimeric due to two bridging iodide ligands. Unlike the Yb(II) compound, the exchange reaction of complex I with SmI2(THF)2 (1 : 1, 25°C) in THF followed by the addition of dimethoxyethane (DME) involves the oxidation of the metal to form the trivalent samarium complex [(2-Me2NCH2C6H4)3CO]2SmI (III), which is isolated in a yield of 60%. The molecular structures of the complexes are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2259700 (I), 2259701 (II), and 2259702 (III)).

Rhenium(V) Tris(pyrazolyl)borate Thiolate Complex with the Disulfide Bridging Ligand: Synthesis and Structure

The reaction of TpReOCl(StBu) (Tp = tris(pyrazolyl)borate anion) with sodium disulfide in dimethoxyethane affords the new binuclear rhenium complex [TpReO(μ-StBu)]2(μ-S2) (I). Complex I can also be synthesized by the reaction of TpReO(StBu)2 with a suspension of manganese(II) bromide in toluene accompanied by the dealkylation of one of the ligands to form one more new complex [TpReO]2(μ-S2)(μ-S) (II) containing the bridging sulfide and disulfide ligands. The structures of two crystalline solvates of complex I with dichloromethane containing the molecules with different conformations of the Re2S2 fragment (Ia and Ib) and complex II are studied by X-ray diffraction (XRD) (CIF files ССDC nos. 2262677, 2262678, and 2267423 for Ia, Ib, and II, respectively).

Lanthanide (Sm, Dy) Complexes with the 9,10-Phenanthrenediimine Redox-Active Ligand: Synthesis and Structures

The complex formation of the redox-active ligand bis(N, N’-2,6-diisopropylphenyl)-9,10-phenanthrenediimine (DippPDI) with alkaline metal (Li, K) and lanthanide (Sm, Dy) cations is studied. The reduction of DippPDI with an alkaline metal excess affords the dianionic form of the ligand (DippPDA2–), which crystallizes with the potassium cation as the coordination polymer [K2(DippPDA)(Thf)3] (Thf is tetrahydrofuran, THF). The reaction of equimolar amounts of the lithium salt with the dianionic form of the ligand and neutral diimine affords the lithium complex with the radical-anion form (DippPSI•–) crystallized as [Li(DippPSI)(Thf)2]. The samarium(III) complex [SmCp*(DippPDA)(Тhf)] (I) is formed by the reduction ofDippPDI with samarocene [Sm (Thf)2] (Cp* is pentamethylcyclopentadienide): both the samarium(II) cation and Cp*– anion are oxidized in the reaction.DippPDI does not react with similar ytterbocene. The dysprosium(III) complexes are synthesized by the ion exchange reactions between DyI3(Thf)3.5 and potassium or lithium salt with theDippPDA2-dianion. Similar complexes [Dy(DippPDA)I(Thf)2] (IIThf) and [Dy(DippPDA)I(Thf)(Et2O)] () are formed in the reactions with the potassium salt depending on the solvent used: a THF-hexane or a diethyl ether-n-hexane mixture, respectively. The coordination of the dysprosium cation by the π system of the conjugated fragment of the NCCN ligand is observed in IIThf, whereas in this coordination is absent. The reaction with Li2(DippPDA) affords the binary complex salt [Li(Тhf)3(Et2O)][DyI2(DippPDA)(Тhf)] (III, crystallization from a THF-Et2O mixture). The crystallization from THF gives the [Li(Тhf)4][DyI2(DippPDA)(Thf)] salt (III') containing the same anion as III. The structures of all new complexes are studied by X-ray diffraction (XRD, CIF files CCDC nos. 2260307–2260313).

Redox-Active Tin(IV) Complexes Based on Sterically Hindered Catecholate Ligands

The oxidative addition of sterically hindered 3,6-dicyclohexyl-o-benzoquinone (L1), 3,5-di-tert-octyl-o-benzoquinone (L2), 4-tert-octyl-o-benzoquinone (L3), and 3,5-bis(2-phenylpropyl)-o-benzoqui-none (L4) to tin(II) chloride in THF affords the corresponding tin(IV) catecholate complexes with the generalformula RCatSnCl2 · 2THF, where Cat is the catecholate fragment; and R is 3,6-с-Hex (I), 3,5-tert-Oct (II), 4-tert-Oct (III), and 3,5-C(Me)2 Ph (IV), regardless of the molar ratio of the starting reactants. The molecu-lar structures of substituted o-benzoquinone L4 and complexes I and III in the crystalline form are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2259370 (L4), 2259371 (I), and 2259372 (III)). The oxidation-reduction properties of synthesized compounds I–IV are studied by cyclic voltammetry.

A comprehensive study on the intermolecular interactions and energy frameworks exist in crystal structures of Form-I, Form-II and Form-III polymorphs of Ethyl maltol

The present study serves as a comprehensive investigation into the molecular crystal structures of three polymorphic forms of ethyl maltol. Crystal structures of the polymorphs grown via slow evaporation and quench cooling crystallization processes were determined through single crystal X-ray diffraction (SCXRD) analysis. Through the utilization of SCXRD data CIF file as an input, we explored the nature and strength of intermolecular interactions, atom pair close contacts, interaction types, 2D fingerprint plots, surface characteristics and percentage of voids present within each polymorph of ethyl maltol. The comparative analysis involves the application of advanced methods, such as Hirshfeld surface analysis and 3D-energy frameworks using Crystal Explorer 17.5. In a supramolecular organization, intermolecular interaction between the carbonyl and hydroxyl groups is a collective structural motif employed among the three polymorphs. However the three polymorphs share common structural features, but the conformations within the crystal packing of each form are different from each other. Shape Index and Curvedness surfaces reveal π stacking interactions with varying properties on differing sides of the molecular moieties between the polymorph. Fingerprint analysis emphasizes that (H…H) is the predominant interaction whereas (O…H) and (H…O) interactions contribute more towards the generation of H-bond interactions in the structure of ethyl maltol polymorphs. The crystal structures of all the three ethyl maltol polymorphs stabilized by various intermolecular contacts within the Hirshfeld surface area was comparable. The interaction energy and the 3D-energy frameworks offer a visualization of the crystal packing topology, enhancing our understanding of the three-dimensional arrangement of molecules and their structural stability. The resulting overall average total energy values for Form-I, Form-II and Form-III polymorphs of ethyl maltol are -56.3 kJ /mol, -74 kJ /mol and -80.45 kJ /mol respectively which reveals that all the three polymorphs show a significant difference in their total energies and reveals further that Form-III polymorph of ethyl maltol is the most stable one while Form-I is the least stable and Form-II is metastable relatively. Moreover, the dispersion energy framework is predominant over the electrostatic energy framework. The void analysis reveals the percentage of volume occupied by the voids present in the unit cell of Form-I, Form-II, and Form-III polymorphs of ethyl maltol are found to be 7.20%, 6.55 %, and 9.43% respectively.

MagGen: A Graph-Aided Deep Generative Model for Inverse Design of Permanent Magnets.

A deep generative model based on a variational autoencoder (VAE), conditioned simultaneously by two target properties, is developed to inverse design stable magnetic materials. The structure of the physics-informed, property embedded latent space of the model is analyzed using graph theory. An impressive ∼96% of the generated materials are found to satisfy the target properties as per predictions from the target-learning branches. This is a huge improvement over approaches that do not condition the VAE latent space by target properties or that do not consider the connectivity of the parent materials from which the new materials are generated. This impressive feat is achieved by using a simple real-space-only representation that can be directly read from material cif files. Model predictions are finally validated by density functional theory calculations on a randomly chosen subset of materials. The performance of the present model is comparable or superior to that of models reported earlier. This model (MagGen) is applied to the problem of designing rare earth-free permanent magnets with promising results.

Planar triangular lattice of the LuMgGaO4: Clustered site-occupancy and the upconversion luminescence of the co-doped Er,Yb ions

The ordered and stable structure of inorganic lattice is the basis of constructing high-efficiency rare earth activated fluorescence, solid-state laser or other optical materials. The mixed sensitized and activated rare earth ions usually keeps a uniform space-occupying and the energy transfer depends much on the doping concentration, while the aggregation of rare earth dopants in order is rare. In this work, a series of LuMgGaO4 phosphors were synthesized and the detail lattice parameters are analyzed through Vietveld refinement and the new CIF file is provided. The site-occupancy of Er3+, Yb3+ shows clustered features and the Er–Yb sublattice structure with various Yb/Er ratios were constructed on the basis of planar triangular lattice. The long-distance excitation energy migration to lattice or defects can be effectively inhibited in case of the hexagonal circle Er-6Yb sublattice, in which the most intense green/red UCL was obtained. All the results demonstrate the novelty of regulating ordered site-occupancy of rare earth ions on a compact planar triangular lattice with higher efficiency of energy migration, which will pave a way for developing phosphor-converted materials or laser materials with better performance.

Co(II) Coordination Compound: Structural and Computational Insights via Crystal Structure, DFT, MEP, NBO and Hirshfeld surface Analyses

A new coordination compound of Co(II) [Co(pydc)2](pydcH2)(Hapy)(H2O)5 (1) (where, pydcH2 = pyridine-2,6-dicarboxylic acid; Hapy = protonated 2- aminopyridine)wassynthesized and characterizedby single crystal X-ray diffraction (SC-XRD) analyses. Crystallographic analysis (CIF file CCDC no. 2236169) revealed that complex 1 has distorted octahedral geometry with pydc coordinated as a tridentate ligand to a metal ion. The electronic structure of the complex was determined using DFT calculations with pseudo potential of LANL2DZ basis function for Cobalt atom while B3LYP/GEN level using 6-31+G* basis set for other atoms. The optimized structure can reproduce the crystal structure with good accuracy at this computational level. Frontier molecular orbital analysis and molecular electrostatic potential (MEP) have been evaluated to understand the reactivity characteristics of the complex. Natural bond orbital (NBO) analysis illustrates the charge transfer between the donor and acceptor sites of the investigated complex. Further, the intermolecular contacts of the complex areanalyzed through Hirshfeld surface analysis and finger print plots.

Simple ePDF: A Pair Distribution Function Method Based on Electron Diffraction Patterns to Reveal the Local Structure of Amorphous and Nanocrystalline Materials.

Amorphous, glassy or disordered materials play important roles in developing structural materials from metals or ceramics, devices from semiconductors or medicines from organic compounds. Their local structure is frequently similar to crystalline ones. A computer program is presented here that runs under the Windows operating system on a PC to extract pair distribution function (PDF) from electron diffraction in a transmission electron microscope (TEM). A polynomial correction reduces small systematic deviations from the expected average Q-dependence of scattering. Neighbor distance and coordination number measurements are supplemented by either measurement or enforcement of number density. Quantification of similarity is supported by calculation of Pearson's correlation coefficient and fingerprinting. A rough estimate of fractions in a mixture is computed by multiple least-square fitting using the PDFs from components of the mixture. PDF is also simulated from crystalline structural models (in addition to measured ones) to be used in libraries for fingerprinting or fraction estimation. Crystalline structure models for simulations are obtained from CIF files or str files of ProcessDiffraction. Data from inorganic samples exemplify usage. In contrast to previous free ePDF programs, our stand-alone program does not need a special software environment, which is a novelty. The program is available from the author upon request.

Coordination Polymer or Cluster: Zinc Bis(3,5-di-tert-octyl-semiquinolate) with Pyrazine

New zinc bis-o-semiquinolate complexes based on 3,5-di-tert-octyl-o-benzoquinone bearing the N-donor ligand (pyrazine) coordinated to the metal are synthesized. Two different products can be obtained depending on the synthesis method: coordination polymer (direct oxidation of metallic zinc with o-quinone (CIF file CCDC no. 2250574 (I)) or polynuclear cluster (exchange reaction (CIF file CCDC no. 2250575 (II)). The coordination polymer is linear and free of intermolecular π,π interactions between the aromatic fragments of the adjacent molecules. The magnetochemical study of complexes I and II shows that intramolecular antiferromagnetic exchange interactions between spins of the o-semiquinolate radical centers dominate.

Synthesis and Structure of the (µ2-OP(O)Ph2)-Linked Dimeric Amide Lanthanum Complex {[ CP(O)Ph2]La[N(SiMe3)2](µ2-OP(O)Ph2)}2 Bearing the Tridentate Heteroscorpionate Ligand. Investigation of the Catalytic Activity in rac-Lactide and ε-Caprolactone Polymerization

The dimeric amide lanthanum complex {[CP(O)Ph2]La[N(SiMe3)2](µ2-OP(O)Ph2)}2 (PzlMe2 is 3,5-dimethylpyrazole) bearing the N,N,O-tridentate heteroscorpionate ligand is synthesized. As found by X-ray diffraction (XRD) (CIF file CCDC no. 2212274), the complex is binuclear and its lanthanum ions are linked by two bridging monoanionic diphenyl phosphinate ligands. The synthesized lanthanum complex demonstrates a high catalytic activity in the polymerization with ring opening of rac-lactide and ε-caprolactone providing the quantitative conversion of 500 equivalents of the monomer to the polymer at room temperature within 360–720 min for rac-lactide and 10–30 min for ε-caprolactone. The formed polylactides are characterized by the atactic microstructure (Pr = 0.54–0.56) and polydispersity indices (PDI) of 1.6–2.5, whereas for polycaprolactone PDI = 2.1–2.8.

Copper(II) Catecholate Complexes with Polypyridyl Ligands

Copper(II) catecholate complexes based on 3,6-di-tert-butyl-o-benzoquinone with N-donor ligands of the phenanthroline series have been synthesized: (3,6-Cat)Cu(Phen) (I), (3,6-Cat)Cu(DPQ) (II), and (3,6-Cat)Cu(DPPZ) (III), where 3,6-Cat is the 3,6-di-tert-butyl-o-benzoquinone dianion, Phen is phenanthroline, DPQ is dipyrido[3,2-d:2',3'-f]quinoxaline, and DPPZ is dipyrido[3,2-a:2',3'-c]phenazine. The synthesized copper(II) complexes demonstrate intramolecular ligand-to-ligand charge transfer responsible for their intense violet color. The electronic structure of the synthesized chromophores was studied by electronic spectroscopy, cyclic voltammetry, and quantum-chemical calculations. The molecular and crystal structures of the synthesized compounds were determined by X-ray diffraction analysis (CIF files CCDC 2 250 975 (I⋅THF), 2 250 976 ([(II⋅THF)(II)]⋅3THF), 2250977 (II)).

Cytotoxic Copper(II) Complexes Based on 2,2'-Bipyridine/1,10- Phenanthroline and 5-(4-Chlorophenyl)-1H-tetrazole: Synthesis and Structures

Five coordination compounds [Cu2(Bipy)2L4]·C2H5OH (Iа, Ib), [Cu2(Dmbipy)2L4] (II),[Cu2(Phen)2L4]·H2O (IIIa), [Cu2(Dmphen)2L4] (IVa), and [Cu2(Phendione’)2L4]·2C2H5OH·2H2O (V) aresynthesized from 5-(4-chlorophenyl)-1H-tetrazole (HL), where Bipy is 2,2'-bipyridine, Dmbipy is 4,4'-dimethyl-2,2'-bipyridine, Phen is 1,10-phenanthroline, Dmphen is 4,7-dimethyl-1,10-phenanthroline, andPhendione’ is 6-ethoxy-6-hydroxy-1,10-phenanthrolin-5-one. The crystal structures of the complexes aredetermined by X-ray diffraction (XRD) of single crystals (CIF files CCDC nos. 2225368 (Ia), 2225369 (Ib),2225370 (II), 2225372 (IIIa), 2225373 (IVa), and 2225371 (V)). The compounds are binuclear due to thebridging function of the tetrazolate anion, and the coordination number of copper is five in all synthesizedcomplexes. The cytotoxic activity of the complexes against the Hep2 and HepG2 cancer cell lines and noncanceroushuman fibroblasts MRC-5 is studied. The complexes exhibit pronounced cytotoxic properties, andcompound V has the maximum selectivity index with respect to the cancer cells.

Nitro-Substituted Pyridinimine Complexes of Pd(II): Synthesis and Inhibition of MAO-B ex vivo

The first ever synthesis of complexes [PdLCl2] (I) and [PdLBr2] (II) was successfully achieved,where L = 2,6-dimethyl-4-nitro-N-(pyridin-2-ylmethylildene)aniline, a ligand with a purported ability toinhibit monoamine oxidase B (MAO-B). To gain insight into the molecular structure of complexes Iand II, as well as the ligand precursor 2,6-dimethyl-4-nitroaniline L4 (CIF files CCDC nos. 2255106 (I),2255105 (II), 2255103 (L), 2255104 (L4)), X-ray diffraction analysis was utilized. Complex I underwent furthercharacterization to determine its stability, solubility, and lipophilicity. Cytotoxicity studies of substancesL, I, and II on human embryonic kidney cell line HEK-293 showed no evidence of cytotoxic activity. To evaluatethe inhibitory activity of new substances L, I, and II as well as established substances III−IX, selegiline,and rasagiline, ex vivo studies were conducted, establishing a structure/activity relationship.

Structural and luminescence studies of Eu3+ doped K2BaSr(PO4)2 phosphor

Eu3+ doped K2BaSr(PO4)2 phosphor which gave red emission, was successfully synthesized by using the solid-state reaction method. The X-ray powder diffraction technique determined the crystal structure and the photoluminescence (PL), and thermoluminescence (TL) were also measured. The XRD pattern of prepared K2BaSr(PO4)2 is good matched with the COD CIF File number 00-100-7161. The structure of the phosphor is orthorhombic. The crystallite sizes are evaluated from diffraction peaks using the Scherrer formula. In PL emission, two peaks are found at 592 nm and 614 nm at 395 nm excitation wavelength. The as-developed phosphor can be used in the development of WLEDs.

Synthesis and Antiproliferative Activity of New Copper, Cobalt, and Zinc Complexes with Abiraterone Acetate

New complexes CuCl2[AbAc]2 (I), CoCl2[AbAc]2 (II), and ZnCl2[AbAc]2 (III) with abiraterone acetate (AbAc) are synthesized. The molecular structure of complex II is determined by X-ray diffraction (XRD) (CIF file CCDC no. 2252346). The cobalt atom coordinates with abiraterone acetate due to the N‑donor pyridine atom. The model processes of hydrolysis of the compounds in acidic and neutral media and their ability to interact with the superoxide radical anion generated in the xanthine–xanthine oxidase enzymatic system are studied. A high activity of complexes I and II is found. The MTT test shows that the antiproliferative activity of compounds I–III against the HCT-116, MCF-7, A-549, and WI-38 cells is comparable with the activity of cisplatin and exceeds that of the initial AbAc for the PC-3 cell line. Complex II also induces cell cycle arrest in the G0/G1 phase of RNA protein synthesis.

Trimethylplatinum(IV) Complexes for MOCVD Applications: A Physicochemical Study

The structure of trimethylplatinum(IV) iodide [(CH3)3PtI]4 (I) (CIF file CCDC no. 22330007) is refined. The structure of the synthesized for the first time trimethylplatinum(IV) complex with tridentate N,N,O-iminoketonate [(CH3)3Pt(C9H17N2O)] (II) is determined by X-ray diffraction (XRD) (CIF file CCDC no. 22330008). The purity of the isolated phases is confirmed by elemental analysis and IR and NMR spectroscopy. The thermal behavior of complex II is studied by thermogravimetry. The energies of ionization and fragmentation of the molecules of complex II leading to the formation of the most stable fragment [(CH3)3Pt]+ are estimated by quantum-chemical calculations. Complex II is tested in the MOCVD processes. The Pt films with the pronounced (111) texture and particle sizes about 100 nm are prepared on Si plates in the presence of oxygen.

Complexes of Cu(II), Co(II), and Zn(II) Terephthalates with Hydroxyalkylamines

The reactions of Cu(II), Co(II), and Zn(II) terephthalates with hydroxyalkylamines (tris(2-hydroxyethyl)amine, bis(2-hydroxyethyl)amine, tris(hydroxymethyl)aminomethane, and bis(2-hydroxyethyl)aminotris(hydroxymethyl)methane) are studied for the first time. The structures and properties of the synthesized complexes are studied by IR spectroscopy, electronic absorption spectroscopy, mass spectrometry, and elemental and thermal analyses. The structure of the binuclear heteroligand [Cu2(TEA)2(Tph)]n·H2O complex is studied by single-crystal X-ray diffraction (XRD) (CIF file CCDC no. 2224437).

Tetranuclear Heterometallic Iron(II)–Lithium Carboxylates Stabilized by N-Donor Ligands: Synthesis and Structure

The multicomponent chemical reactions of Fe(SO4)∙7H2O, Li(Рiv), K(Рiv) (Рiv is pivalate anion), and heterocyclic N-donor ligands (pyridine (Рy), 1,10-phenanthroline (Рhen)) in anhydrous acetonitrile under an inert atmosphere afford new heterometallic tetranuclear complexes [FeII2Li2(Рiv)6(Рy)4] (I) and [FeII2Li2(Рiv)6(Рhen)2] (II) in which all carboxylate anions act as bridging ligands. The molecular and crystal structures of the compounds are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2220576 (I) and 2220577 (II·2CH3CN). In the studied complexes, the iron(II) atoms exist in the distorted octahedral ligand environment.