MeOH Solution Research Articles

Recognition of dicarboxylic acids and diphosphonic acids using anthracene-based diamidine: formation of amidinium-carboxylate and amidinium-phosphonate salt bridges in a protic solvent

ABSTRACT The formation of a stable ‘amidinium-carboxylate’ salt bridge, even in a competing protic solvent (MeOH), was observed based on the binding experiments of anthracene-based diamidine (1) and dicarboxylic acids. The formation of 1:1 binding complexes of the diamidine 1 and dicarboxylic acids was confirmed by DOSY NMR, ESI-Mass, titration experiments and a single crystal X-ray analysis. Similarly, the formation of the ‘amidinium-phosphonate’ salt bridge in the MeOH solution was also evidenced by the complexation of the diamidine 1 and diphosphonic acids.

Design, synthesis, characterization, and anticancer activity of a novel series of O-substituted chalcone derivatives

A new series of O-substituted chalcone derivatives bearing an/a allyl-, prenyl- or propargyl-substituent at different positions of rings A and B and their derivatives as drug leads, was designed, synthesized, and characterized. The chalcone derivatives were synthesized via base catalyzed Claisen-Schmidt condensation in MeOH or EtOH solutions of appropriately substituted aromatic ketones with O-allyl, and O-propargylvanillin, respectively. The intermediates O-substituted phenylketone derivatives were firstly synthesized by nucleophilic substitution reaction. All the newly synthesized compounds were characterized by IR, NMR spectral data and elemental analyses. A preliminary cytotoxicity was performed with the compounds (1a, 1b, 2a, 2b, 3a, 3b, 4a, 5a-f, 6a-d, 7a-d) and the positive control, doxorubicin towards CCRF-CEM leukemia cells. Amongst them, compounds 1a, 2a, 5b-d, 6b, 7a, 7c and doxorubicin displayed IC50 values below 20 µM while other compounds were less or not active at up to 50 µM. Remarkably interesting cytotoxic effects, with IC50 values below 1 µM were recorded with 5c against HCT116 p53-/- colon adenocarcinoma cells, 5e against CCRF-CEM cells and MDA-MB-231-BCRP breast adenocarcinoma cells, and 6b against HCT116 p53+/+ cells and HCT116 p53-/- cells.

Synthesis and characterization of copper(II) complex with 2,6-diacetylpyridine-bis(phenylhydrazone)

The syntheses, physicochemical and structural properties of the novel Cu(II) complex with 2,6-diacetylpyridine bis(phenylhydrazone) (L), of the formula [CuL 2 ]Br 2 are presented. In the reaction of warm MeOH solutions of the ligand, 2,6-diacetylpyridine bis(phenylhydrazone) and CuBr 2 in molar ratio 2:1 resulted in formation of black single crystals of the bis(ligand) complex. This is the first Cu(II) complex with this ligand that is characterized by SC-XRD. Two ligand molecules are coordinated in the usual tridentate mode, via nitrogen atoms of the pyridine ring, and two azomethine nitrogen atoms, forming distorted octahedral environments of the metal ion.

Synthesis, and spectroscopic, nanostructure, surface morphology, and density functional theory studies of new charge-transfer complexes of amifampridine with π-acceptors

The charge transfer (CT) complexes formed between the potassium-channel-blocking drug amifampridine (AMFP) and the π-acceptors; chloranilic acid (CLA) and 2,5-dihydroxy-p-benzoquinone (DHBQ) in both MeOH solutions, and the solid-state were synthesized and fully characterized. The stoichiometry of the complexes formed in MeOH is 1:1, while those of the solid complexes are 2:1 and 1:1 (donor: acceptor) for CLA and DHBQ, respectively. The CT complexes were studied in terms of their formation constants (KCT), molar extinction coefficients (εCT), and spectrophysical and thermodynamic properties, and the results demonstrated the high stability of the complexes in MeOH. The limits of detection and quantification for the complexes by UV–Vis spectrophotometry were also determined. The surface morphologies, particle sizes, and elemental compositions of the complexes were determined, utilizing X-ray powder diffraction, scanning electron microscope, and energy-dispersive X-ray techniques. The molecular structures, and the electronic properties of the complexes were investigated using B3LYP and WB97XD DFT calculations employing 6–31++G(d,p) basis sets, revealing that the magnitude of the CT is 0.357 e in AMFP-CLA and 0.317 e in AMFP-DHBQ, indicating that CLA is a better electron acceptor than DHBQ. The UV–Vis spectral bands observed for AMFP-CLA and AMFP-DHBQ experimentally in MeOH at 488 and 535 nm, respectively, while these bands were calculated at 493.0 at 535.6 nm, respectively, in the same solvent (MeOH). Both bands were found to be due to HOMO→LUMO excitation, where that in the AMFP-CLA complex is an internal electronic transition and that in AMFP-DHBQ complex is a charge transfer based transition from AMFP to DHBQ. Natural bond orbital calculations indicated that the CT processes LP(2)O11→LP*(1)H12 (127.62 kcal mol−1) and LP(1)N20→LP*(1)H12 (317.46 kcal mol−1) in AMFP-DHBQ, and LP(2)O9→LP*(1)H10 (94.84 kcal mol−1) and LP(1)N23→ LP*(1)H10 (363.42 kcal mol−1) in AMFP-CLA provide extra stability to the complexes.

Open versus Interpenetrated: Switchable Supramolecular Trajectories in Mechanosynthesis of a Halogen-Bonded Borromean Network

Summary Precise control over topologically intricate molecular architectures remains an open challenge for chemists due to their inherent structural complexity. We report a simple solvent-free strategy to selectively prepare two multi-component supramolecular crystalline systems based on the halogen bond, endowed with either an unknot topology or a Borromean-type entanglement. Real-time in situ monitoring of the solvent-free mechanochemical synthesis of these three-component halogen-bonded ionic co-crystals reveals that the choice of milling conditions leads to a switch in the supramolecular reaction trajectory, resulting in the selective formation of an open halogen-bonded network or a halogen-bonded Borromean-type assembly.

A Dynamic Combinatorial Library of Cyclic AuI2NiII Complexes with Cysteine/Penicillamine Showing Solvent-Controlled Crystallization.

A dynamic combinatorial library (DCL) is a set of molecular species existing in equilibrium in solution that can undergo self-assembly via reversible chemical bonds. Here, we report a unique DCL system that shows the independent crystallization of products from solvents with slightly different polarities. The reaction of a 1:1 mixture of [Au2(dppm)(dl-cys)2]2- and [Au2(dppm)(dl-pen)2]2- with Ni2+ in solution gave a DCL containing 10 cyclic AuI2NiII molecules of [Au2Ni(dppm)(dl-cys/dl-pen)2]. Upon crystallization, three kinds of enantiomeric pairs, homoleptic-heterochiral C/A-[Au2Ni(dppm)(d-cys)(l-cys)], homoleptic-homochiral [Au2Ni(dppm)(d-pen)2]/[Au2Ni(dppm)(l-pen)2], and heteroleptic-homochiral [Au2Ni(dppm)(d-cys)(d-pen)]/[Au2Ni(dppm)(l-cys)(l-pen)], were produced from the reaction solutions of MeOH, MeOH/H2O, and EtOH/H2O, respectively. The independent crystallization was explained by a combination of the different hydrogen-bonding interactions of the AuI2NiII molecules in the crystal and the different thermodynamic stabilities of the molecules in solution.

Antioxidant and Cytotoxic Activity Studies in Series of Higher Amino Acid Schiff Bases

In this work, the antioxidant activity of the higher amino acid Schiff bases, which were prepared as the monosodium salts (1a–3a) and the neutral forms (1b–3b) was determined by DPPH scavenging assay. In pure MeOH solution, the scavenging ability of Schiff bases 1a-3a were higher than 1b-3b, but lower than ascorbic acid. The activity followed the order 3 (a,b) > 2 (a,b) > 1 (a,b). On the other hand, Schiff bases 2a and 3a behaved as the most effective scavengers of the DPPH radical in methanol-water mixture (v:v, 1:3). And, they were found to be have lower SC50 values in this mixture compared to pure methanol. In vitro cytotoxicity of these Schiff bases was studied against human cervical cancer cells (HeLa), human breast adenocarcinoma cells (MCF-7), and human normal embryonic kidney cells (HEK293). For HeLa cell line, Schiff bases 1a-3a exhibited a litttle high activity than 1b, but very low activity than doxorubicin. Schiff bases 2b and 3b had no cytotoxicity against HeLa cell. For MCF-7 cell line, Schiff bases 1a, 3a, 1b and 3b nearly were inactive at 100 µM, whereas 2a increased cell proliferation in the all tested concentration range. Differently, Schiff base 2b showed the highest cytotoxicity and killed 90 percent of MCF-7 cells at concentration of 100 µM. For HEK-293, doxorubicin was strongly cytotoxic. Despite this, Schiff bases 1a, 3a and 3b were inactive, whereas the others showed little weak toxicity.

Enhanced permeance for PDMS organic solvent nanofiltration membranes using modified mesoporous silica nanoparticles

Organic solvent nanofiltration (OSN) is emerging as an efficient and emerging approach for separation and purification of solute from organic solvents, which however were severely underdeveloped because of the low permeance of membranes. Herein, a novel mixed matrix membrane (MMM) was developed by incorporation of modified mesoporous silica nanoparticle (MSN) into commercially-available polydimethylsiloxane (PDMS) matrix for removal of trace impurities, such as Evans blue or vitamin B12, from different organic solvents. Notably, because of the designed nanoscale spaces originated from MSN, the permeance of the optimized MMM reached up to 31.2 L m−2.h−1.MPa−1, around 17-fold enhancement compared with that of pristine PDMS membrane. Low-field nuclear magnetic resonance was employed to trace the solvent state in the MMM. The MMM exhibited high MeOH absorption capability but low-swelling attribute, certificating the high permeance and long-term stability of the MMM. The MMM was stably tested in MeOH solution for more than 80 h, indicating the great promise for future practical OSN applications.

Catalytic Disproportionation of Formic Acid to Methanol by using Recyclable Silylformates

AbstractA novel strategy to prepare methanol from formic acid without an external reductant is presented. The overall process described herein consists of the disproportionation of silyl formates to methoxysilanes, catalyzed by ruthenium complexes, and the production of methanol by simple hydrolysis. Aqueous solutions of MeOH (>1 mL, >70 % yield) were prepared in this manner. The sustainability of the reaction has been established by recycling of the silicon‐containing by‐products with inexpensive, readily available, and environmentally benign reagents.

Catalytic Disproportionation of Formic Acid to Methanol by using Recyclable Silylformates

A novel strategy to prepare methanol from formic acid without an external reductant is presented. The overall process described herein consists of the disproportionation of silyl formates to methoxysilanes, catalyzed by ruthenium complexes, and the production of methanol by simple hydrolysis. Aqueous solutions of MeOH (>1 mL, >70 % yield) were prepared in this manner. The sustainability of the reaction has been established by recycling of the silicon-containing by-products with inexpensive, readily available, and environmentally benign reagents.

Crystal structure and magnetic properties of a pentanuclear copper(II) 12-metallacrown-4 complex derived from glutaroimide-dioxime

Reaction of copper(II) perchlorate with glutaroimide-dioxime (H3gido) in MeOH solution led to a quasi co-planar 12-metallacrown-4 complex [Cu5(Hgido)4(ClO4)2]·CH3OH(1). The structure of complex 1 has been confirmed by X-ray analysis: two types of similar 12-metallacrown-4 units are connected into 1D chain by perchlorate anions. The temperature dependent magnetic susceptibilities analysis indicates that the antiferromagnetic exchange interaction through the Cu(II)peripheral–Cu(II)central and Cu(II)peripheral–Cu(II)peripheral pathways are J1 = -41.3 and J2 = -14.2 cm−1, respectively. The field-dependent magnetization at 2 K confirms the ground state of St = 3/2.

Metal-Organic Frameworks with Hexakis(4-carboxyphenyl)benzene: Extensions to Reticular Chemistry and Introducing Foldable Nets.

Nine metal–organic frameworks have been prepared with the hexagon-shaped linker 1,2,3,4,5,6-hexakis(4-carboxyphenyl)benzene (H6cpb) by solvothermal reactions in dimethylformamide (dmf) or dimethylacetamide (dmac) with acetic acid or formic acid as modulators: [Bi2(cpb)(acetato)2(dmf)2]·2dmf CTH-6 forms a rtl-net; 2(H2NMe2)[Cu2(cpb)] CTH-7 forms a kgd-net; [Fe4(cpb)(acetato)2(dmf)4] CTH-8 and [Co4(cpb)(acetato)2(dmf)4] CTH-9 are isostructural and form yav-nets; 2(HNEt3)[Fe2(cpb)] CTH-10 and the two polymorphs of 2(H2NMe2)[Zn2(cpb)]·1.5dmac, Zn-MOF-888 and CTH-11, show kgd-nets; [Cu2(cpb)(acetato)2(dmf)2]·2dmf, CTH-12, forms a mixed coordination and hydrogen-bonded sql-net; and 2(H2NMe2)[Zn2(cpb)] CTH-13, a similarly mixed yav-net. Surface area values (Brunauer–Emmett–Teller, BET) range from 34 m2 g–1 for CTH-12 to 303 m2 g–1 for CTH-9 for samples activated at 120 °C in dynamic vacuum. All compounds show normal (10-fold higher) molar CO2 versus N2 uptake at 298 K, except the 19-fold CO2 uptake for CTH-12 containing Cu(II) dinuclear paddle-wheels. We also show how perfect hexagons and triangles can combine to a new 3D topology laf, a model of which gave us the idea of foldable network topologies, as the laf-net can fold into a 2D form while retaining the local geometry around each vertex. Other foldable nets identified are cds, cds-a, ths, sqc163, clh, jem, and tfc covering the basic polygons and their combinations. The impact of this concept on “breathing” MOFs is discussed. I2 sorption, both from gas phase and from MeOH solution, into CTH-7 were studied by time of flight secondary ion mass spectrometry (ToF-SIMS) on dried crystals. I2 was shown to have penetrated the crystals, as layers were consecutively peeled off by the ion beam. We suggest ToF-SIMS to be a method for studying sorption depth profiles of MOFs.

Crystal structures of 3β,19-dihydroxyandrost-5-en-17-one, 5, and its monohydrate, [(5).H2O]: A survey of the structures of related di- and tri-substituted hydroxy derivatives and their solvated compounds

The crystal structures of 3β,19-dihydroxyandrost-5-en-17-one, 5, and its monohydrate, [((5).H2O]], are reported. The monohydrate, isolated from a solution of 5 in 50% aqueous methanol, recrystallizes in the orthorhombic space group, P212121, while that of the anhydrous compound, isolated from solutions of THF, Me2CO, EtOAc or dry MeOH, recrystallizes in the monoclinic space group, P21. Apart from the different orientation of the 3-HO group, the conformations of the steroid molecules in 5 and [(5).H2O]: are similar. The two-dimensional structure of 5 consists of sheets of molecules formed from strong classical O3—H3⋯O19(OH) and O19—H19···O3(OH), augmented by weaker C—H⋯O hydrogen bonds. Noticeably the presence of the C19 hydroxyl group results in the replacement of the O3—H3⋯O17(one) hydrogen bonds as the strongest intermolecular interaction found in the stable polymorphs of the mono-hydroxylated compound, 3β-hydroxyandrost-5-en-17-one (dehydroepiandrosterone). An additional structural difference between 3β-hydroxyandrost-5-en-17-one and 3β,19-dihydroxyandrost-5-en-17-one is that the steroid molecules are most strongly linked head-to-tail in the former but head-to-middle fashion in the latter. In the three dimensional structure of [((5).H2O]], each steroid molecule is directly connected to another by a O19—H19⋯O3(OH) hydrogen bond and indirectly to two others via the water molecule. Each water molecule forms three hydrogen bonds, namely O3—H3⋯Ow, Ow—Hw1⋯O17 and Ow—Hw2⋯O19. As found for most hydrated steroids, the hydrate molecules have strong influences on the structure.In addition to the reporting of the crystal structures of 5 and [(5).H2O], we report on a survey of the crystal structures of related di- and tri- hydroxy-17-one derivatives as well as solvated compounds.

Zn(II) and Cd(II) monomer, dimer and polymer compounds coordinated by benzoic acid and 4-acetylpyridine: Synthesis and crystal structures

Reaction of MO (MO = Metal oxide, M = Zn(II) or Cd(II)) with benzoic acid (HBz) in H2O/MeOH mixture as solvent yields two benzoate compounds: [Zn(µ-Bz)2]n (1) and [Cd(Bz)2(H2O)3] (2). In addition, the reaction between M(MeCO2)2 (M = Zn(II) or Cd(II)) with HBz and 4-acetylpyridine (4-Acpy) in a 1:2:4 M ratio and in MeOH solution, leads to the formation of [Zn(µ-Bz)2(4-Acpy)]2 (3) and [Cd(µ-Bz)2(4-Acpy)2]2 (4). These four compounds have been fully characterized by analytical and spectroscopic techniques. Besides, their crystal structures have been elucidated revealing a 1D coordination polymer (1), a monomer (2), a paddle-wheel (3) and a dimer (4). In 1, the Zn(II) ion is four-coordinated in a tetrahedral geometry while in 3 is penta-coordinated in a square-pyramidal geometry. By contrast, compounds 2 and 4 exhibit seven-coordinated Cd(II) ions in a pentagonal-bipyramidal geometry. In these set of compounds, the benzoate ligand presents different coordination modes such as bidentate bridged (µ2-η1:η1) (1 and 3), chelate (µ1-η2) (2) and both bridged and chelate (µ2-η2:η1) (4). Besides, their extended structures have been analyzed. Finally, the UV–Vis and fluorescence spectra of all the compounds have been recorded as well as their quantum yields calculated.

Effect of the Nature and the Position of Defects on the Chiral Expression in Poly(3-alkylthiophene)s

Polymers produced with the most used controlled polymerization method with the simplest initiators, namely the Kumada catalyst transfer condensation polymerization (KCTCP) with Ni2+ salts, all have one regiodefect distributed along the polymer backbones. The irregularity created by these defects can be split up into three components, i.e., the nature of the defect, the position of the defect, and the additional inhomogeneity created by mixing polymers with the defect at different positions. In this research, the influence of these three parameters on the chiral expression of poly(3-alkylthiophene)s (P3ATs) is investigated separately for the first time. A series of chiral P3ATs with one tail-to-tail (TT) or head-to-head (HH) defect in different positions is synthesized by means of the Pd(RuPhos) protocol, and their chiral expression and that of their mixtures are studied via UV–vis and circular dichroism (CD) spectroscopy. For the polymers with an HH defect, it is found that the position at the very beginning of the polymer chain is the most optimal to obtain the largest chiral expression, and the obtained signal is even the highest ever reported for PTs in chloroform and MeOH solutions. When a TT defect is incorporated into the polymer, the chiral expression is much weaker, and the most optimal position of the defect is a little shifted toward the middle of the chain compared to their HH analogues. For the mixtures of the polymers with an HH defect, a weighted average of the signals of its constituents is obtained, but for the mixtures of the polymers with a TT defect different results are obtained. When 25% of each polymer is mixed, no chiral response is obtained, and when more of the polymers with the defect more toward the chain ends are incorporated, a chiral response higher than that of any of the component polymers is recorded. This shows that the chiral expression is not only influenced by the nature or the position of a defect, but also by the mixing of polymers with a defect in different positions.

Bidentate ligands and their Cu(II) complexes: Structural characterization, electrochemical properties and biological evaluation

In this manuscript, three bidentate ligands 2-[(2-methoxybenzylidene)amino]phenol (HA1), 2-[(3,4,5-trimethoxybenzylidene) amino]phenol (HA2) and 2-[(2,3,4-trimethoxybenzylidene) amino]phenol (HA3) were synthesized from the reaction of the 2-aminophenol and methoxy benzaldehyde derivatives in MeOH solution. The Cu2+ metal complexes of these ligands were obtained in the 1:1 (M:L) ratio. All the compounds were characterized by the micro analytical and spectroscopic techniques. The single crystals of the bidentate ligands (HA2 and HA3) were obtained from the recrystallization from the MeOH solution and their structural characterizations were conducted by the X-ray diffraction method. Antimicrobial activity studies of the bidentate ligands and their Cu2+ metal complexes were tested towards S. aureus, E. coli, B. cereus, B. subtilis, S. typhimurium as bacteria and C. albicans as fungi and the complex Cu2+ of the ligand HA2 showed the highest activity against to the S. aureus. While the ligands HA2 and HA3 do not show the activity against the bacteria and fungi, the ligand HA1 has the activity against to the S. typhimurium, S. aureus and C. albicans. Electrochemical behaviours of all compounds have been investigated in DMF solution and it was found that the cathodic and anodic values of the [CuA3(Cl)H2O] complex shifted to the more positive regions owing to the positions of the methoxy groups on the benzaldehyde ring.

New stable colored complex of Al3+ with 1',3',3'‐trimethylspiro[2H‐1‐benzopyran‐2,2'‐indoline] (BIPS)

AbstractUltraviolet‐visible (UV‐vis) absorption, flash photolysis, and 1H and 13C NMR spectroscopy were used to investigate the mechanism of formation and structure of complexes in the 1',3',3'‐trimethylspiro[2H‐1‐benzopyran‐2,2'‐indoline] (SP, also well known as BIPS) with Al3+ (inorganic salts) in ethanol (EtOH), methanol (MeOH), and in aqueous MeOH solutions. A labile (equilibrium constants ≤ 5000 M−1) complex of SP and Al3+ with broad absorption band in the UV‐vis with λmax = 380 nm appeared promptly in the presence of an excess of Al3+. The slow formation of a stable complex (SC) between Al3+ and two merocyanine (MC) forms of SP with an intensive absorption band at λmax = 430 nm is observed with a yield of 1.0 upon keeping the solutions of these two compounds at constant concentration ratio [Al3+] ≥[SP]/2 in the dark. The rate constants of such SC formation were close to the corresponding rate constant of the transformation of SP into MC in the dark (5.0×10−5‐1×10‐3 s‐1, depending upon the solvent). The photolysis of the SC with visible light (λ > 400 nm) results in the total conversion of the SC into SP. The SC forms promptly after the addition of Al3+ at concentrations of the same order as those of MC. This method allows detection of [Al3+] to concentrations as low as 50 nM. The kinetics and thermodynamic parameters of the SP and MC reactions and of their complex formation with Al3+ are discussed.

Snail shell-shaped chiral substituted helical polyacetylene: preparation, characterization and infrared emissivity performance

The first snail shell-shaped helical polyacetylenes (SHPAs) were synthesized from the copolymerization between l-serine-grafted propargylamine (LSA) and propargylamine (PA). The novel structure was obtained at the monomer input proportion of 50%. The monomer (LSA) and copolymers (poly(LSAm-co-PAn)) were characterized by 1H nuclear magnetic resonance, Fourier transform infrared spectroscopy, ultraviolet visible spectroscopy, circular dichroism and transmission electron microscopy. The infrared emissivity of poly(LSA50-co-PA50) investigated at 8–14 μm was 0.451, which was much lower than the other copolymers. This was because the poly(LSA50-co-PA50) could form the obvious intramolecular interaction and self-assembled to a snail-shell shape by intermolecular hydrogen bonding in MeOH solution. Meanwhile, the conjugation performance of the main chain was enhanced. Consequently, the abundant hydrogen bonds formed through N–H and C=O bonding and the strong conjugate properties both could decrease the unsaturation degree, as well as change the heat conduction mode in the molecules, thereby reducing the infrared emissivity. This strategy provided a new direction to achieve the controllable infrared stealth.

Cleaner production of micronutrients from sesame seed pressed cake: a comparative study

This work presents the valorisation of a biowaste obtained from sesame oil production by using ultrasound-assisted (UAE) extraction, which is an environmentally friendly method consuming relatively less energy. Sesame seed pressed cake provided from different origins (Sudan, Turkey, and Yemen) was extracted by two solvent systems (ethanol and methanol). The response surface approach (RSA) as a statistical experimental design method has been utilized for the investigation of experimental design, optimization, and process parameter effect through central composite face-centered (CCFC) design of RSA. The optimum conditions for sesame seed pressed cake extraction are as follows: in regard to ethanol (EtOH), amplitude was 38.62% along with 44.68% of EtOH solution for 63.31 min with respect to sesame seed pressed cake of Sudan; regarding Turkish samples, the amplitude was 38.5% along with 54.18% of EtOH solution for 59.72 min, whereas the optimal conditions were found as 39.01% of amplitude, 60.69 min of extraction time, and 56.62% of EtOH solution for the sample from Yemen to obtain the maximum yields of each dependent variable such as total phenolics (TP) and total flavonoids (TF). Concerning methanol (MeOH), amplitude was 36.79% along with 72.73% of MeOH solution for 60.01 min with respect to sesame seed pressed cake of Sudan; regarding Turkish samples, the amplitude was 37.04% along with 71.49% of MeOH solution for 60.08 min, whereas the optimal conditions were found as 37.79% of amplitude, 60.69 min of extraction time, and 79.96% of MeOH solution for the Yemeni samples.

Unexpected Formation of an Alcoholate Bridge in the Coordination Polymer of Adduct Zn(OOCPh)2[O(H)Me]4 and Bidentate γ,γ'-Bipyridyl

The recrystallization of Zn(OOCPh)2[O(H)Me]4 (1) (chloroform diffusion to a methanolic solution, dissolution of the powder in boiling MeCN, and exposure of the methanolic solution at room temperature) is found to be accompanied with the formation of {Zn(µ-OOCPh)3Zn(µ-OOCPh)}n polymer single crystals. The diffusion of an MeOH solution of γ,γ'-bipyridyl to a methanolic solution of 1 (in the ratio 1 : 1) gives rise to the formation of {Zn(µ-dipy)(η2-OOCPh)(OOCPh)}n polymer, and the same reaction in the ratio 2 : 1 under strong dilution gives rise to methanol deprotonation to yield {Zn[(µ-OMe)(µ-OOCPh)Zn(OOCPh)]2(µ-dipy)2}n. The product compounds are characterized by chemical analysis, X-ray crystallography, and IR spectroscopy.