Series Of Coordination Compounds Research Articles

Structure and performance regulation of energetic complexes through multifunctional molecular self-assembly.

The design of novel energetic compounds constitutes a pivotal research direction within the field of energetic materials. However, exploring the intricate relationship between their molecular structure and properties, in order to uncover their potential applications, remains a challenging endeavor. Therefore, employing multi-molecule assembly techniques to modulate the structure and performance of energetic materials holds immense significance. This approach enables the creation of a new generation of energetic materials, fueling research and development efforts in this field. In this study, a series of coordination compounds are synthesized by utilizing tetranitroethide (TNE) as an anion, which possesses a high nitrogen and oxygen content. The synthesis involves the synergistic modification between metal ions and small molecule ligands. Characterization of the obtained compounds is carried out using various techniques, including single crystal X-ray diffraction, IR spectroscopy, elemental analysis, and simultaneous TG-DSC analysis. Additionally, the energy of formation for these compounds is calculated using bomb calorimetry, based on the heat of combustion. The detonation performances of the compounds are determined through calculations using the EXPLO 5 software, and their sensitivities to external stimuli are evaluated.

Crystal structure and infrared and Raman spectra of K3[Cr(CN)5NO].2H2O, a member of an iconic family of complexes in coordination chemistry

Potassium pentacyanonitrosylchromate(I) dihydrate salt, K3[Cr(CN)5NO].2H2O, forms spontaneously from aqueous solution below about 15 °C while the anhydrous salt is obtained above 20 °C. The molecular structure of the dihydrate has been determined by X-ray diffraction, taking full advantage of modern data collection, advanced space group and structure solution and refinement. It crystallizes in the monoclinic space group Cc, is isomorphic to the Mn(I) analog, and shows the pseudo-symmetry of space super-group C2/c. The [Cr(CN)5NO]3− ion has an umbrella-like conformation with the equatorial Cr-CN bonds slightly bent away from the Cr-NO link. The crystallographic study fills a gap left in the literature on accurate structural data for alkaline and alkaline-earth salts of [M(CN)5NO]n- (M = V, Cr, Mn, Fe) series of coordination compounds. We also report here the solid-state vibration structure of the new compound, as probed by IR and Raman spectroscopy. Water mode assignments were assisted through deuterium enrichment. The thermal dehydration behavior complements structural and spectroscopic information on water molecules.

Rational Design of Electronically Labile Dinuclear Fe and Co complexes with 1,10-Phenanthroline-5,6-Diimine: A DFT study.

A series of coordination compounds of redox-active 1,10-phenanthroline-5,6-diimine with CoII bis-diketonates and FeII dihydrobis(pyrazolyl)borates has been computationally designed by means of density functional theory (DFT UB3LYP*/6-311++G(d,p)) calculations of their electronic structure, energy characteristics, and magnetic properties. Four types of complexes differing by the nature and position of the terminal metal-centered fragments have been considered. The performed systematic calculations have revealed the systems capable of undergoing thermally initiated spin-state switching rearrangements, including those governed by the synchronized mechanisms of spin crossover and valence tautomerism. The predicted magnetic characteristics allow one to consider the dinuclear cobalt complexes and heterometallic Co/Fe compounds with 1,10-phenanthroline-5,6-diimine as building blocks for molecular and quantum electronics devices. © 2019 Wiley Periodicals, Inc.

Synthesis, structures, and luminescent properties of a series of coordination compounds based on O,N-donor ligands

Four novel coordination compounds, namely, [Cd2(pydc)2(bpp)2(H2O)2]⋅ bpp⋅2H2O (1), [Zn(Hpydc)2]⋅3H2O (2), [Cd(dhb)2(phen)2] (3), and [Zn(L)(phen) (H2O)] (4) (H2pydc = 2,6-pyridinedicarboxylic acid, Hdhb = 2,6-dihydroxybenzoic acid, H2L = 5-((2'-cyano-1,1'-biphenyl-4-yl) methoxy)isophthalic acid, bpp = 1,3-bis(4-pyridyl)propane, and phen = 1,10-phenanthroline) have been hydrothermally synthesized and characterized by IR spectroscopy, thermogravimetric analysis and X-ray single crystal diffraction analyses. Compounds 1, 2 and 3 feature zero-dimensional (0D) structures and 1 is further extended to one-dimensional (1D) chain structure through C-H⋅⋅⋅O hydrogen bonding interactions. Compound 4 exhibits 1D chain structure. The luminescent properties of compounds 3 and 4 have also been studied.

Bis(diphenylphosphino)amines-containing ruthenium cymene complexes as potential anti-Mycobacterium tuberculosis agents

Several ruthenium complexes have been investigated regarding anti-Mycobacterium tuberculosis (anti-MTb) activity, with some diphosphine-containing ruthenium complexes comparable to first and second line drugs. However, to the best of our knowledge, there is no PNP-containing ruthenium complexes applied as metallodrugs. Thus, this study focused on the synthesis, characterization and anti-MTb activity of a new series of coordination compounds with general formula [RuCl(η6-p-cymene)(PNRP)]X (R=CH2Py (Py=pyridine)−[1a], CH2Ph (Ph=phenyl)−[1b], Ph−[1c] and p-tol (p-tol=p-tolyl)−[1d]; X=PF6− or BF4−). The complexes were fully characterized by NMR (1H, 31P{1H}), vibrational spectroscopy (FTIR), ESI-MS, molar conductance, elemental analysis and X-ray diffraction studies. The molecular structures of [1a]PF6, [1c]BF4 and [1d]PF6 were determined and confirm the spectroscopic and ESI-MS data. The complexes were used in anti-MTb trials, and the preliminary results are presented. The complexes are promising anti-MTb agents with MIC90 (Minimum Inhibitory Concentration of compounds required to inhibit the growth of 90% of MTb) values comparable with the Ethambutol, the reference drug used in this work, and complex [1a]BF4 presented the highest selectivity index.

Introducing 2-(2-carboxyphenoxy)terephthalic acid as a new versatile building block for design of diverse coordination polymers: synthesis, structural features, luminescence sensing, and magnetism

In this work, an ether-bridged aromatic carboxylic acid, 2-(2-carboxyphenoxy)terephthalic acid (H3cpta), was applied as an unexplored building block for the generation of a novel series of coordination compounds, which represent the first examples of structurally characterized products derived from H3cpta, thus opening up its use as a versatile building block in crystal engineering research. The obtained products were formulated as [Cd(μ-Hcpta)(phen)(H2O)]n (1), [Mn(μ-Hcpta)(phen)(H2O)]n (2), {[Cd3(μ3-Hcpta)(μ4-cpta)(μ-Cl)(H2O)4]·2H2O}n (3), {[Cd3(μ6-cpta)2(py)2]·5H2O}n (4), [Mn3(μ5-cpta)2(2,2′-bipy)2]n (5), [Mn3(μ4-cpta)2(phen)3(H2O)2]n (6), {[Zn3(μ3-cpta)2(phen)3]·3H2O} (7), [Cd2(μ4-cpta)(μ-Cl)(phen)2]n (8), [Cd3(μ5-cpta)2(phen)2(H2O)2]n (9), [Cd3(μ4-cpta)2(phen)3(H2O)2]n (10), [Cd3(μ5-cpta)2(H2biim)2]n (11), [Zn2(μ6-cpta)(μ-Hbiim)]n (12), and [Ni3(μ3-cpta)2(phen)3(py)3(H2O)3]n (13). These compounds were assembled in the presence of an optional N-donor ancillary ligand, which was selected from 1,10-phenanthroline (phen), pyridine (py), 2,2′-bipyridine (2,2′-bipy), or 2,2′-biimidazole (H2biim). The obtained compounds 1–13 were fully characterized, including by IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), powder (PXRD) and single-crystal X-ray diffraction. The structures of 1–13 vary from a discrete 0D dimer (1) to the 1D (2, 3, 7, and 13) and 2D (5, 6, and 8–11) coordination polymers, as well as to the 3D metal–organic frameworks (MOFs 4 and 12). Such a wide structural diversity of 1–13 is guided by the following factors: a type of metal(II) node and counter anion, a deprotonation degree of the principal H3cpta block, and/or a type of an auxiliary ligand. Topological classification of H-bonded (in 1) and metal–organic (in 2–13) underlying networks was performed, disclosing the following topological types: sql (in 1), 2C1 (in 2 and 7), 3,4,5L45 (in 5, 9, and 11), 3,4L128 (in 6 and 10), 3,3,4L29 (in 8), and SP 1-periodic net (in 13), as well as some topologically unique nets (in 3, 4, and 12). Besides, magnetic properties of 2, 5, 6, and 13 were studied and modeled, revealing antiferromagnetic interactions between adjacent metal(II) centers. In addition, luminescence properties were investigated for 1, 3, 4, and 7–12; MOF 4 can be used as a sensitive material for the detection of Fe3+ ions in aqueous solution through the luminescence quenching effect.

Five metal imidazole dicarboxylate-based compounds comprising M3(MIDC)2 entities (M = Zn2+, Co2+, Mn2+): syntheses, structures and properties

Five metal imidazole dicarboxylate-based compounds, {[Zn3(MIDC)2(4,4′-bipy)3](4,4′-bipy)·8H2O}n (1), {[Co3(MIDC)2(4,4′-bipy)3](4,4′-bipy)·6H2O}n (2), {[Co3(MIDC)2(py)2(H2O)2]}n (3), {[Mn6(MIDC)4(py)5(H2O)4]}n (4), and {[Mn3(MIDC)2(Phen)3(H2O)2]}n (5) (H3MIDC = 2-methyl-1H-imidazole-4,5-dicarboxylic acid; 4,4′-bipy = 4,4′-bipyridine; py = pyridine; Phen = 1,10-phenanthroline), have been synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. We control the coordination modes of H3MIDC via hydrazine and obtained a series of coordination compounds containing honeycomb-like [M3(MIDC)2]n layers. We also investigated the effects of different neutral terminal or bridging ligands on [M3(MIDC)2]n layers. Coplanar [M3(MIDC)2]n layers and 4,4-bipy were used to construct 3-D frameworks of 1 and 2. Puckered [M3(MIDC)2]n layers were found in 3–5; 4 is the first [M3(L)2]n layer structure with two crests and troughs during each period (L = imidazole-4,5-dicarboxylic acid or its analog). Compound 5 is the first puckered [M3(L)2]n layer structure decorated by chelating neutral ligands. Compound 1 exhibits weak blue photoluminescence in the solid state at room temperature. Variable-temperature magnetic susceptibility measurements of 2–5 indicate strong antiferromagnetic interactions.

A New Family of Doubly Cyclopalladated Diimines. A Remarkable Effect of the Linker between the Metalated Units on Their Cytotoxicity

The cyclopalladation of a series of symmetric diimines with the formula (RC6H4CH═NZ)2, where Z = CH2 or (CH2)2OCH2 and R = p-Cl, p-OMe, p-NO2, and o-Cl, is described. Optimal conditions to obtain the dimetalated compounds were found to be palladium(II) acetate, in toluene, at 60 °C and with a reaction time of 2–4 h. The reactivity of the dimetalated compounds with monodentate, bidentate, and bis(monodentate) Lewis bases was also studied. The cytotoxic activity of some selected compounds was evaluated against a panel of adenocarcinoma cell lines (colon HCT116 and breast MCF7 and MDA-MB231). Compounds containing the fragment NCH2CH2OCH2CH2OCH2CH2N exhibited a remarkable cytotoxic activity in the three cancer cells assayed, but complexes containing the NCH2CH2N fragment showed no activity. It seems that the length and flexibility of the central saturated chain in the imine molecule, as well as its lipophilicity and hydrophilicity, explain the different cytotoxicity of the two series of coordination compounds...

Family of Cofacial Bimetallic Complexes of a Hexaanionic Carboxamide Cryptand

A series of coordination compounds has been prepared comprising manganese, iron, nickel, and zinc bound by a hexaanionic cryptand where carboxamides are anionic N-donors. The metal complexes have been investigated by X-ray crystallography, and possess metal centers in trigonal monopyramidal geometries with intermetallic distances spanning d(Mn,avg) = 6.080 Å to d(Ni,avg) = 6.495 Å. All complexes featuring trigonal monopyramidal metal(II) ions crystallize in Cc, and feature extended three-dimensional networks composed of cryptate anions linked by bridging potassium countercations. We also report the first solid state structure of the free cryptand ligand, which features no guest in its cavity and which possesses an extended hydrogen-bonding network. SQuID magnetometry data of the metal complexes reveal weak antiferromagnetic coupling of the metal centers. Only the diiron(II) complex exhibits reversible electrochemistry, and correspondingly, its chemical oxidation yields a powder formulated as the diiron(III) congener. The insertion of cyanide into the intermetallic cleft of the diiron(II) complex has been achieved, and comparisons of its solid state structure to the recently reported dicobalt(II) analogue are made. The antiferromagnetic coupling between the diiron(II) and the dicobalt(II) centers when bridged by cyanide does not increase significantly relative to the unbridged congeners. A one-site model satisfactorily fits Mössbauer spectra of unbridged diiron(II) and diiron(III) complexes whereas a two site fit was needed to model the iron(II) centers that are bridged by cyanide.

Effects of the Au(I)-Au(I) closed-shell attraction on the electronic and phosphorescent properties in a series of coordination compounds: A theoretical study

The Au(I)–Au(I) closed-shell or aurophilic attraction has been the subject of interest in the experimental and theoretical chemistry fields, due to the intriguing properties associated to it. The presence of phosphorescence in “aurophilic” compounds has been addressed to a wide range of applications, but it has not yet been fully understood. A theoretical study on the electronic and phosphorescent properties of the following series of dinuclear gold complexes has been performed: [Au2(dmpm) (i-mnt)] (1), [Au2(μ-Me-TU) (μ-dppm)] (2), and [Au2(μ-G)(μ-dmpe)] (3). Full geometry optimizations at the second-order Møller–Plesset perturbation theory (MP2) were carried out for each of the species. These calculations made evident that, at the ground-state geometry, the Au(I) cations allocated at the center of the ring show a short Au–Au distance below the sum of the van der Waals radii, at the range of the aurophilic attraction. An intermolecular Au(I)–Au(I) closed-shell attraction for a pair of the systems under study is found. This attraction is comparable to that of the hydrogen bonds. The phosphorescent properties experimentally observed for this series were also characterized through ab initio techniques. The obtained results allow to fit reasonably the excitation energies with the experimental data and to identify a correlation between the strength of the Au(I)–Au(I) interaction and the phosphorescent behavior. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011

From Single-Molecule Precursors to Hybrid ZnS Nanostructures

A series of coordination compounds containing [Zn(amine)]2+ cationic complexes and alkyldithiocarbamates (RR'dtc-), as counter anions, are reported here: [Zn(amine)x][RR'dtc]2, where amine = ethylenediamine (en), diethylenetriamine (dien), 1,2-diaminopropane (dap) and, R,R' = ethyl (Et); butyl (Bu) and methyl (Me), hexyl (Hex). Hybrid nanoplates composed of hexagonal-ZnS nanoparticles and organic components were obtained after solution phase thermolysis of such precursors in oleylamine. These hybrid materials show quantum confinement effects in their optical spectra and convert into cubic-ZnS after further thermal treatment.

Second-order non-linear optical response of metallo-organic compounds: towards switchable materials

A series of coordination compounds, [M(PM-L) 2(NCS) 2], with large aromatic ligands (PM-L) and a divalent metal ion (M II=Mn, Fe, Co, Ni and Zn) have been synthesized. The magnetic data are consistent with divalent metal ions in an octahedral ligand field environment. Hyper-Rayleigh scattering measurements show an enhancement of the molecular hyperpolarizabilities ( β) from Ni compounds (with two unpaired electrons) to Mn compounds (five unpaired electrons). In the case of the Fe(II) metal ion, the influence of the ligand on the β values is reported. This work provides attractive information for the design of switchable materials based on the spin-crossover phenomenon.

A study on superoxide dismutase activity of some model compounds

The synthesis and characteristics of a binuclear ligand N,N,N′,N′-tetrakis (2′-benzimidazolyl methyl)-1,4-diethylene amino glycol ether (EGTB) and its series of coordination compounds containing copper(II), iron(III), and manganese(II) with and without exogenous bridging ligand which was imidazolate ion (Im −), bipyridine (bpy), or 1,10-phenanthroline (phen) are reported. Depending on the redox potentials by cyclic voltammetry, the coordination compounds can act as catalysts for the dismutation of superoxide radicals (O 2 −). The detection of the rate constant of the reaction of superoxide ion with nitroblue tetrazolium (NBT) which is inhibited by superoxide dismutase (SOD) and its model compounds of the EGTB system has been performed by a modified illumination method. The rate constants R Q of the catalytic dismutation have been obtained.

Electronic spectra of Cu(II) crystal complexes with S-methylthiosemicarbazones

Electronic spectra for a series of coordination compounds of copper(II) with tridentant ligands of salicyl aldehyde S-methylthiosemicarbazone and 8-quinoline aldehyde S-methylthiosemicarbazone were investigated. Coordinations of central ions were determined on the basis of X-ray data and IR spectra. Electronic transitions were detected by processing the diffusion-reflection spectra according to theKubelka-Munk theory. Identifications proved the presence of bands corresponding to intraligand transition, charge transfer spectra and the transition of d-d type which are the result of the elimination of d-orbital degeneration for Cu(II) ions in the crystal field. The effect of the symmetry of coordination polyhedrons is discussed.

Some macrokinetic structural aspects of heterogeneous thermal dissociation reactions

Abstract In order to determine the kinetic parameters with physical meaning, large series of coordination compounds with analogous structures must be studied.

Secondary Amide Deriviatives of Lanthanons

Abstract A new series of coordination compounds between lanthanon (III) isopropoxides and N-phenyl, N (2-chlorophenyl), N (4-nitrophenyl), N (2-nitro-4-methoxyphenyl) acetamide and N-phenylbenzamide has been isolated and studied. The compounds of formula Ln (OPri)2(L), Ln (OPri) (L)2 and Ln(L)3, (where L is the deprotonated secondary amide) are coloured solids. The compounds were characterized by means of chemical analyses and infrared spectral data.

Reactions of substituted thioureas with transition metal nitrates and perchlorates

A series of co-ordination compounds, Me( Xtu) 2,4 Y 2, where Me = Co and Ni, Xtu = ethylenethiourea (etu) or tetramethylthiourea (tmtu) and Y = [ClO 4] − or [NO 3] − have been prepared. Using magnetic, i. r. and electronic spectroscopic data the compounds Co( etu) 4( NO 3) 2 and Co( tmtu) 4(ClO 4) 2 are shown to be tetrahedral with co-ordination of the four sulfur donors. The compounds Co(etu) 2(NO 3) 2 and Co(tmtu) 2(NO 3) 2 involved co-ordination to both sulfur of the thiourea and nitrate oxygen. These compounds possess a distorted six co-ordinate configuration with assymetrically bound nitrates. Ni(tmtu) 2(NO 2) 2 exists as two forms, one orange, which appears to be a highly distorted octahedral complex and one green, which has a much less distorted octahedral geometry. I.R. data also indicate that the “square planar compound,” Ni(etu) 4(NO 3) 2, possesses weakly co-ordinated nitrates.