Methanol Solvent Mol-ecule Research Articles

Bis[2-(isoquinolin-1-yl)phenyl-κ2 N,C 1](2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline-κ2 N,N')iridium(III) hexa-fluorido-phosphate methanol monosolvate.

The title compound, [Ir(C15H10N)2(C19H12N4)]PF6·CH3OH, crystallizes in the C2/c space group with one monocationic iridium complex, one hexa-fluorido-phosphate anion, and one methanol solvent mol-ecule of crystallization in the asymmetric unit, all in general positions. The anion and solvent are linked to the iridium complex cation via hydrogen bonding. All bond lengths and angles fall into expected ranges compared to similar compounds.

Pyrazine-bridged polymetallic copper-iridium clusters.

Single crystals of the mol-ecular compound, {Cu20Ir6Cl8(C21H24N2)6(C4H4N2)3]·3.18CH3OH or [({Cu10Ir3}Cl4(IMes)3(pyrazine))2(pyrazine)]·3.18CH3OH [where IMes is 1,3-bis-(2,4,6-trimethylphen-yl)imidazol-2-yl-idene], with a unique heterometallic cluster have been prepared and the structure revealed using single-crystal X-ray diffraction. The mol-ecule is centrosymmetric with two {Cu10Ir3} cores bridged by a pyrazine ligand. The polymetallic cluster contains three stabilizing N-heterocyclic carbenes, four Cl ligands, and a non-bridging pyrazine ligand. Notably, the Cu-Ir core is arranged in an unusual shape containing 13 vertices, 22 faces, and 32 sides. The atoms within the trideca-metallic cluster are arranged in four planes, with 2, 4, 4, 3 metals in each plane. Ir atoms are present in alternate planes with an Ir atom featuring in the peripheral bimetallic plane, and two Ir atoms featuring on opposite sides of the non-adjacent tetra-metallic plane. The crystal contains two disordered methanol solvent mol-ecules with an additional region of non-modelled electron density corrected for using the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The given chemical formula and other crystal data do not take into account the unmodelled methanol solvent mol-ecule(s).

Comprehensive Exploration of Optics and Magnetism in a Hydrothermally Synthesized Nickel(II) Complex.

The hydrothermal reaction of 2-MeIm (2-MeIm: 2-methylimidazole) with nickel sulfate hexahydrate in methanol afforded a mononuclear complex formulated as [Ni(SO4)(2-MeIm)2(H2O)3]·CH3OH (1). The title compound was described by X-ray single-crystal diffraction, thermal assessment, IR, and UV-vis spectroscopy. The crystal structure of 1 is composed of segregated [Ni(SO4)(2-MeIm)2(H2O)3] neutral entities and a solvent methanol molecule. Two (2-MeIm) ligands, a sulfate group, and a water molecule reside in the equatorial positions of the vertices in this 6-fold coordination. Two aqua ligands lay in the apical positions, resulting in a subtly distorted octahedral framework, as was supported by spectroscopic analysis. The complex's self-assembly is firmly governed by robust O-H···O/N-H···O interactions. Further details on these bonds have been furnished via Hirshfeld surface scrutiny and 2D fingerprint plots. As proven by TGA/DSC analysis, raising the temperature of 1 above 60 °C instigates progressive decomposition stages, which culminates in the production of metal oxide as the ultimate product at 700 °C. The optical analysis suggests the dielectric nature of the material with large direct and indirect gap energies of 5.25 and 4.96 eV, respectively. The results of magnetic studies suggest that 1 undergoes a transition to a magnetically ordered state below 6 K.

Insights into oxidovanadium (3,4,5-trimethoxyphenyl) porphyrin: A comprehensive study of synthesis, crystal structure, Hirshfeld surface analysis and computational studies

The synthesis of Oxidovanadium 5,10,15,20-tetrakis(3,4,5-trimethoxyphenyl) porphyrin [VO(T(OMe)3PP)], complex 1, was successfully achieved and its structure was confirmed through single crystal analysis. This analysis revealed a deformed octahedral structure caused by the vanadium cation's interaction with six components, which includes a vanadyl oxygen atom. It is interesting that an oxygen atom from a methanol solvent molecule was discovered to fill an axial position in the arrangement. Further investigation involved the use of fingerprint plots and Hirshfeld surface analysis with dnorm mapping of complex 1. Significantly, interactions like H⋯H (62.4 %), O⋯H (11.8 %)/H⋯O (10.4 %), and C⋯H (7.4 %)/H⋯C(5.9 %) were emphasized in the Hirshfeld surface analysis. In addition, the Density Functional Theory (DFT) investigations, shows the HOMO-LUMO energy gap determined through experimentation in solvent closely correlated with the theoretically calculated energy difference of 0.96 eV for complex 1. Finally, Molecular Electrostatic Potential (MEP) analysis were performed.

Bis[2,3-bis-(thio-phen-2-yl)pyrido[3,4-b]pyrazine]-silver(I) perchlorate methanol disolvate.

The title compound, [Ag(C15H9N3S2)2]ClO4·2CH3OH, is monoclinic. The AgI atom is coordinated by pyrido N atoms and is two-coordinate; however, the AgI atom has nearby O atoms that can be assumed to be weakly bonded - one from the perchlorate anion and one from the methanol solvate molecule. One of the thienyl groups on a 2,3-bis-(thio-phen-2-yl)pyrido[3,4-b]pyrazine is flipped disordered and was refined to occupancies of 68.4 (6) and 31.6 (6)%.

Chlorophyll and pheophytin protonated and deprotonated ions: Observation and theory.

Pheophytin a and chlorophyll a have been investigated by electrospray mass spectrometry in the positive and negative modes, in view of the importance of the knowledge of their properties in photosynthesis. Pheophytin and chlorophyll are both observed intensely in the protonated mode, and their main fragmentation route is the loss of their phytyl chain. Pheophytin is observed intact in the negative mode, while under collisions, it is primarily cleaved beyond the phytyl chain and loses the attaching propionate group. Chlorophyll is not detected in normal conditions in the negative mode, but addition of methanol solvent molecule is detected. Fragmentation of this adduct primarily forms a product (-30amu) that dissociates into dephytyllated deprotonated chlorophyll. Semi-empirical molecular dynamics calculations show that the phytyl chain is unfolded from the chlorin cycle in pheophytin a and folded in chlorophyll a. Density functional theory calculations have been conducted to locate the charges on protonated and deprotonated pheophytin a and chlorophyll a and have found the major location sites that are notably more stable in energy by more than 0.5eV than the others. The deprotonation site is found identical for pheophytin a and the chlorophyll a-methanol adduct. This is in line with experiment and calculation locating the addition of methanol on a double bond of deprotonated chlorophyll a.

Deep insights into novel hexa-coordinated phenoxy-bridged trinuclear Ni(II) asymmetric salamo-like complexes affected by different types of combined solvents

By changing different types of combined solvents, two novel trinuclear Ni(II) complexes, [Ni3(L)2(NO3)2(MeOH)2] (1) and [Ni3(L)2(NO3)2]2 (2) were constructed from an asymmetric salamo-type ligand H2L and Ni(NO3)2·6H2O, respectively. The specific coordination modes of the two complexes have been clearly confirmed by X-ray single-crystal data. The results manifested that the complexes 1 and 2 possess similar coordination structures with solvent methanol molecules involved in coordination in complex 1, however, no coordinated solvent molecule appears in complex 2. The ligand (L)2− units were shown to be involved in coordination with Ni(II) atoms by analysis of infrared and UV–vis absorption spectroscopy. DFT and Hirshfeld surfaces analyses were performed on the complexes. Fluorescent strengths of both complexes were markedly lower compared to the ligand H2L and decreased gradually with increasing concentration of Ni(II) ions, which indicated the charge transfer from H2L to Ni(II) ions involved in the coordination.

Pd-catalyzed oxidative carbonylation of sulfurated substrates: Theoretical mechanistic outcomes

In the present study, a detailed computational investigation has been carried out on the recently reported PdI2/KI-catalyzed conversion of 1-(methylthio)-3-yn-2-ols to thiophene-3-carboxylate esters, using 2-methyl-1-(methylthio)oct-3-yn-2-ol as the model substrate. On the basis of a number of mechanistic hypotheses that were taken into account, outcomes on the energetic feasibility of the generally-accepted reaction scheme for this process have been provided. The current investigation indeed dissects the role of each species coming into play during the reaction, in each step of the mechanism. In detail, the contribution of co-catalytic KI for the demethylation of the S-containing nucleophilic agent, concertedly to the 5-endo-dig mechanism, from the early stage of the reaction has been highlighted, as well as the role of transient dimethyl ether cation for the dehydration step and that of the solvent methanol molecules for the formation/energy stabilization of the product. The calculated barriers are in good agreement with available experimental data.

Circularly Polarized Luminescence from New Heteroleptic Eu(III) and Tb(III) Complexes.

The complexes [Eu(bpcd)(tta)], [Eu(bpcd)(Coum)], and [Tb(bpcd)(Coum)] [tta = 2-thenoyltrifluoroacetyl-acetonate, Coum = 3-acetyl-4-hydroxy-coumarin, and bpcd = N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane-N,N'-diacetate] have been synthesized and characterized from photophysical and thermodynamic points of view. The optical and chiroptical properties of these complexes, such as the total luminescence, decay curves of the Ln(III) luminescence, electronic circular dichroism, and circularly polarized luminescence, have been investigated. Interestingly, the number of coordinated solvent (methanol) molecules is sensitive to the nature of the metal ion. This number, estimated by spectroscopy, is >1 for Eu(III)-based complexes and <1 for Tb(III)-based complexes. A possible explanation for this behavior is provided via the study of the minimum energy structure obtained by density functional theory (DFT) calculations on the model complexes of the diamagnetic Y(III) and La(III) counterparts [Y(bpcd)(tta)], [Y(bpcd)(Coum)], and [La(bpcd)(Coum)]. By time-dependent DFT calculations, estimation of donor-acceptor (D-A) distances and of the energy position of the S1 and T1 ligand excited states involved in the antenna effect was possible. These data are useful for rationalizing the different sensitization efficiencies (ηsens) of the antennae toward Eu(III) and Tb(III). The tta ligand is an optimal antenna for sensitizing Eu(III) luminescence, while the Coum ligand sensitizes better Tb(III) luminescence {ϕovl = 55%; ηsens ≥ 55% for the [Tb(bpcd)(Coum)] complex}. Finally, for the [Eu(bpcd)(tta)] complex, a sizable value of glum (0.26) and a good quantum yield (26%) were measured.

Solvent-mediated oxidative polymerization to atomically dispersed iron sites for oxygen reduction

Fe single-atom catalysts open up broad prospects for oxygen reduction reaction (ORR), but the chemical state evolution of Fe species before forming isolated sites is rarely understood. Herein, mechanistic investigation on the formation of isolated Fe sites is presented through solvent-mediated oxidative pyrrole polymerization strategy. The slow reaction kinetics of oxidative Fe3+ ions with the predesigned methanol solvent molecules can endow highly dispersed Fe sites in polypyrrole and thus Fe single-atom catalysts after pyrolysis. The Fe single-atom catalyst (Fe-SA/PNC) performs superior ORR activity with a half-wave potential of 0.90 V versus RHE and 12.8 times higher turnover frequency than that of commercial Pt/C. When assembled into Zn-air batteries, the Fe-SA/PNC cathode delivers a 1.68 V open circuit potential and ultra-long cycling stability over 9000 cycles, superior to the most reported catalysts so far. Experimental and theoretical results reveal that the rich adjacent non-coordinated graphitic nitrogen atoms can enhance electronic conductivity and promote O2 adsorption and OH- desorption, thus enabling high oxygen reduction and battery performances.

Silver Dependent Enantiodivergent Gold(I) Catalysed Asymmetric Intramolecular Hydroamination of Alkenes: A Theoretical Study

We report a theoretical study of the first silver-dependent enantiodivergent gold-catalysed reaction. The combination of a single chiral binuclear gold(I) chloride complex and silver perchlorate catalyses the asymmetric intramolecular hydroamination of alkenes and affords both enantiomers of the products by applying a simple solvent change from toluene to methanol. A gold-silver chloride adduct that occurs only in methanol appears to control the enantioinversion. If one gold atom coordinates and activates the alkene moiety, the other gold is included in an adduct with silver chloride, which coordinates a methanol solvent molecule and further interacts with the amine function. If the use of toluene implies free anions and affords (S)-enantiomer, methanol allows a proximal interaction with the amine, leads to an opposite stereodifferentiation of the two diastereomeric intermediates during the final protodeauration step and results in the (R)-enantiomer.

Bis(nitrato-κO)(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ4 N)zinc(II) methanol monosolvate.

The two ZnII atoms in the crystal structure of the title complex, [Zn(NO3)2(C10H24N4)]·CH3OH, have a distorted octa-hedral coordination sphere, defined by 1,4,8,11-tetra-aza-cyclo-tetra-decane (cyclam) N atoms in the equatorial plane and nitrate O atoms in the axial sites. The conformation of the cyclam is trans-III (R, R, S, S), which is typical for metal-cyclam complexes. Nitrate anions are involved in intra- and inter-molecular hydrogen bonding with the N-H groups of the ZnII-cyclam unit. Together with the methanol solvent mol-ecule, the hydrogen-bonding network connects the ZnII-cyclam units into ribbons running parallel to the a axis.

Crystal structure of poly[[di-aqua-tetra-μ2-cyanido-platinum(II)iron(II)] methanol 4/3-solvate]: a three-dimensional Hofmann clathrate analogue.

In the title polymeric coordination compound, {[FePt(CN)4(H2O)2]·1.33CH3OH} n , the FeII cation (site symmetry 4/mm.m) is coordinated by the N atoms of four cyanide anions (CN-) and the O atoms of two water mol-ecules, forming a nearly regular [FeN4O2] octa-hedron. According the Fe-N and Fe-O bond lengths, the FeII atom is in the high-spin state. The cyanide anions act in a bridging manner to connect the FeII and PtII atoms. The [Pt(CN)4]2- moieties (Pt with site symmetry 4/mm.m) have a perfect square-planar shape. The latter anion is located perpendicular to the FeN4 plane, thus ensuring the creation of a three-dimensional framework. The crystal structure features methanol solvent mol-ecules of which 4/3 were located per FeII cation. These solvent mol-ecules are located in hexa-gonal pores; they inter-act with coordinating water mol-ecules through weak hydrogen bonds. Other guest mol-ecules could not be modelled in a satisfactory way and their contribution to the scattering was removed by a mask procedure.

Halogen bonding in cadmium(II) MOFs: its influence on the structure and on the nitroaldol reaction in aqueous medium.

A solvothermal reaction of Cd(II) with the dicarboxyl-functionalized arylhydrazone pro-ligands, 5-(2-(2,4,6-trioxotetrahydro-pyrimidin-5(2H)-ylidene)hydrazineyl)isophthalic acid (H5L1) and 5-(2-(2,4-dioxopentan-3-ylidene)hydrazineyl)isophthalic acid (H3L2), or their halogen bond donor centre(s) decorated analogs 2,4,6-triiodo-5-(2-(2,4,6-trioxotetrahydropyrimidin-5(2H)-ylidene)hydrazineyl)isophthalic acid (H5L3) and 5-(2-(2,4-dioxopentan-3-ylidene)hydrazineyl)-2,4,6-triiodoisophthalic acid (H3L4), leads to the formation of known [Cd(H3L1)(H2O)2]n (1) and new {[Cd(HL2)(H2O)2(DMF)]·H2O}n (2), [Cd(H3L3)]n (3) and {[Cd2(μ-H2O)2(μ-H2L4)2(H2L4)2]·2H2O}n (4) coordination compounds, respectively. The aggregation of mononuclear units via Cd-OC and Cd-OH2 coordination and CAr-I⋯I types of intramolecular halogen bonds lead to a dinuclear tecton 4. Both CAr-I⋯O and CAr-I⋯I types of intermolecular halogen bonds play a fundamental role in the supramolecular architectures of the obtained metal-organic frameworks 3 and 4. Theoretical (DFT) calculations confirmed the presence of the CAr-I⋯O and CAr-I⋯I halogen bonds in 3 and 4 and allowed their characterisation. The formation of intermolecular noncovalent interactions between the attached iodine substituents to the hydrazone ligands and polar solvent (water or methanol) molecules promoted, at least in part, the solubility of the corresponding complexes (3 and 4), which act as homogeneous catalyst precursors in the Henry reaction between aldehydes and nitroethane. The corresponding β-nitroalkanol products were obtained in good yields (66-79%) and with good diastereoselectivity (threo/erythro ca. 72 : 28) in water at room temperature.

Photoregulated Morphological Transformation of Spiropyran Derivatives Achieving the Tunability of Interfacial Hydrophilicity.

Regulation of self-assembly morphology is an effective strategy to obtain advanced functional materials with expected properties. However, achieving remarkable morphological transformation by light irradiation is still a challenge. Herein, three simple spiropyran derivatives (SP1, SP2, and SP3) are constructed, achieving different degrees of morphological transformation from nanospheres to hollow tadpole-like structures (SP3), tubular structures (SP2), and microsheets (SP1) after ultraviolet light irradiation. Interestingly, the hollow tadpole-like structures (SP3) can further extend to Y-shaped or T-shaped tubular morphology. In the process, SP1, SP2, and SP3 can be isomerized from a closed-ring form (hydrophobicity) to an open-ring form (hydrophilicity) in different degrees, interacting differently with methanol solvent molecules. The formation of hollow structures or microsheets along with the isomerization of spiropyran derivatives contributes to the adjustment of the hydrophilicity of the interface. Therefore, SP1, SP2, and SP3 with photoregulated morphological transformation show promising applications in tunable interface materials.

Chiral crystallization of a zinc(II) complex.

The compound, {6,6'-dimeth-oxy-2,2'-[(4-azaheptane-1,7-di-yl)bis-(nitrilo-meth-an-yl-idyne)]diphenolato}zinc(II) methanol monosolvate, [Zn(C22H27N3O4)]·CH3OH, at 298 K crystallizes in the ortho-rhom-bic space group Pna21. The Zn atom is coordinated by a penta-dentate Schiff base ligand in a distorted trigonal-bipyramidal N3O2 geometry. The equatorial plane is formed by the two phenolic O and one amine N atom. The axial positions are occupied by two amine N atoms. The distorted bipyramidal geometry is also supported by the trigonality index (τ), which is found to be 0.85 for the mol-ecule. In the crystal, methanol solvent mol-ecule is connected to the complex mol-ecule by an O-H⋯O hydrogen bond and the complex mol-ecules are connected by weak supra-molecular inter-actions, so achiral mol-ecules generate a chiral crystal. The Hirshfeld surface analysis suggests that H⋯H contacts account for the largest percentage of all inter-actions.

Synthesis, X-ray crystal structure and BVS calculation of Co(II) complex of pyrimidine derived Schiff base ligand: Approached by Hirshfeld surface analysis and TDDFT calculation

A new Co(II) complex [Co(L)(Cl)2]•(MeOH)2 (1) has been synthesized using a symmetrical Pyrimidine derived Schiff base ligand 2,2′-((2E,2′E)-2,2′-(butane-2,3-diylidene)bis(hydrazin-1-yl-2-ylidene))bis(4,6-dimethylpyrimidine) (L) and characterized by single crystal X-ray crystallography analysis. The solid-state structure of 1 is pseudooctahedral with two methanol molecules outside the coordination sphere. The said complex is stabilized through various intermolecular H-bonding incorporating non coordinated solvent methanol molecules. Bond Valence Sum (BVS) calculation confirms that the central cobalt atom in 1 exists as ‘+2′ oxidation state instead of ‘+3′. Hirshfeld surface analysis is performed to determine the intermolecular interactions and the crystal packing of the title complex. The 2D fingerprint plots associated with the Hirshfeld surface clearly present each significant interaction involved in the structure, by quantifying them in an effective visual manner. The electronic transition of complex 1 was recorded in methanol solvent and the electronic distribution of HOMO−LUMO can be rationalized theoretically (through time-dependent density functional theory (TDDFT)).

New Family of Heptanuclear Lanthanide {Ln7} Clusters: Synthesis, Structure, and Magnetic Studies

AbstractA new family of heptanuclear lanthanide complex [Ln7(L)2(LH)4(dbm)5(OH)2(CH3OH)4]⋅xCHCl3⋅yCH3OH⋅zH2O {Ln=TbIII (1), DyIII (2) and ErIII (3) and LH3=(E)‐2‐(hydroxymethyl)‐6‐(((2‐hydroxyphenyl) imino) methyl)‐4‐methylphenol} [in 1, x=6, y=3, z=3; in 2, x=5, y=1, z=6; and in 3, x=4, z=2] has been prepared in presence of lanthanide chloride(III) salts and β‐diketonate co‐ligand dibenzoylmethane (dbm). Single crystal XRD reveals heptanuclear ensemble formed by collective action of two fully deprotonated [L]3− ligands, four double deprotonated [LH]2−, two μ3‐OH− ligands, five anionic [dbm]− β‐diketonate co‐ligands and two terminal methanol solvent molecules. This heptanuclear unit comprises of two [Dy4(μ2‐O)5(μ3‐OH)]+6 core sharing a common metal vertex Dy1 through which centre of inversion has passed for overall molecule. All the complexes have been magnetically characterized and dynamic AC magnetic studies reveals slow relaxation of magnetism present in dysprosium analogue (2).

Synthesis, spectroscopic characterization and quantum chemical studies of a dioxomolybdenum(VI) complex with an N,S-substituted pyridoxal thiosemicarbazone

The new compounds Pyridoxal N-allyl-S-methylthiosemicarbazone (L) and the dioxomolybdenum(VI) complex [MoO2(L)CH3OH] have been synthesized and characterized by elemental analysis, UV–Vis, FT-IR, Raman and 1H NMR spectra, and also by the single crystal X-ray diffraction technique. Single crystals of the cis-dioxomolybdenum(VI) complex were obtained by evaporating its methanol solution. According to the single-crystal X-ray diffraction investigation, the molybdenum atom in the complex is in a distorted octahedral coordination. The sixth coordination site is occupied by the oxygen atom of a methanol solvent molecule. The methanol coordination between the oxygen and molybdenum atoms is the weakest bond, with a MoO bond length of 2.355 Å. The geometries and vibrational spectra of the pyridoxal thiosemicarbazone (L) and its complex are explained by quantum chemical calculations.

Crystal Structure and DFT Calculations of Zn(II)-NN’O Schiff Base Complex

The structure of the ZnII complex with NN’O-donor ligand N-(2-pyridyl)methyl-2-hydroxy-3,5-di-tert-butylbenzaldimine (1H) [Zn(C21H27N2O)2]·3CH3OH is described. The Zn (II) metallic centre presents a five-coordinate environment with a square-pyramidal distorted geometry (τ-factor 0.14). One ligand acts as tridentate and another ligand as bidentate [Zn(1-κ3N,N’,O)(1-κ2N,O)]·3CH3OH. The three methanol solvent molecules interact with the zinc complex by hydrogen-bonds (H-bonds). This structure was modelled with Density Functional Theory (DFT) calculations and a good correlation between the experimental parameters and the calculated ones was obtained. The X-ray diffraction single crystal structure of the Zn(II) complex with NN’O-donor pyridino-imino-phenolate ligand (1H) [Zn(1)2]·3CH3OH is described and compared with the modelled by DFT calculations.