Acid Dianion Research Articles

Three new Ag(I) coordination architectures based on mixed ligands: Syntheses, structures and photoluminescent properties

Abstract Three new silver (I) coordination complexes, [Ag2(1,2-bdc)(phdat)]n (1), [Ag2(NO2-bdc)(phdat)]n (2), [Ag4(nta)3(phdat)NO3]n (3) (1,2-bdc=phthalic acid dianion, NO2-bdc=5-nitro-1,3-benzenedicarboxylic acid dianion, nta=nicotinic acid anion, phdat=2,4-diamine-6-phenyl-1,3,5-triazine) have been hydrothermally synthesized by the reactions of silver nitrate and phdat with the homologous ligands 1,2-H2bdc, NO2-H2bdc, and Hnta, respectively, and characterized by single-crystal X-ray diffractions, IR spectra, elemental analyses thermogravimetric analyses (TGA). The compound 1 exhibits a chiral 3D network with cbs/CrB self-dual topological net, which contains two kinds of single helical chains. For compound 2, the 3D network is comprised of two kinds of similar 2D sheets with the topological symbol of sql-type packed in AABBAA mode by Ag–N/O weakly contacts. And compound 3 has 2D double layer architecture, consisting of the 2D plane with hcb-type topological symbol connected by Ag–O weakly coordinations. The photoluminescent properties associated with the crystal structures of three compounds have also been measured.

Synthesis, characterization, and cytotoxicity of platinum(II)/palladium(II) complexes with 4-toluenesulfonyl-L-amino acid dianion and diimine/diamine

Eight new platinum(II)/palladium(II) complexes with 4-toluenesulfonyl-L-amino acid dianion and diimine/diamine ligands, [Pd(en)(Tsile)]·H2O (1), [Pd(bipy)(Tsile)] (2), [Pd(bipy)(Tsthr)]·0.5H2O (3), [Pd(phen)(Tsile)]·0.5H2O (4), [Pd(phen)(Tsthr)]·H2O (5), [Pd(bqu)(Tsthr)]·1.5H2O (6), [Pt(en)(Tsser)] (7), and [Pt(en)(Tsphe)]·H2O (8), have been synthesized and characterized by elemental analyses, 1H NMR and mass spectrometry. The crystal structure of 7 has been determined by X-ray diffraction. Cytotoxicities were tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and sulforhodamine B assays. The complexes exert cytotoxicity against HL-60, Bel-7402, BGC-823, and KB cell lines with 4 having the best cytotoxicity against HL-60, Bel-7402, and BGC-823 cell lines; the compounds are less cytotoxic than cisplatin.

Synthesis, characterization and cytotoxicity of platinum(II)/palladium(II) complexes with 1,3-diaminopropane and 4-toluensulfonyl-l-amino acid dianion

Eight novel platinum(II)/palladium(II) complexes with 1,3-dap and 4-toluensulfonyl-l-amino acid dianion, [Pt(1,3-dap)(TsalaNO)]·0.5H2O (1a), [Pt(1,3-dap)(TsvalNO)] (1b), [Pt(1,3-dap)(TspheNO)] (1c), [Pt(1,3-dap)(TsserNO)] (1d), [Pd(1,3-dap)(TsalaNO)]·1.5H2O (2a), [Pd(1,3-dap)(TsvalNO)] (2b), [Pd(1,3-dap)(TspheNO)] (2c) and [Pd(1,3-dap)(TsileNO)] (2d) have been synthesized and characterized by elemental analysis, IR, UV, 1H NMR and mass spectrometry techniques. Crystal structure of the complex 1b has been determined by X-ray diffraction. The cytotoxicity was tested by MTT and SRB assays. The complexes (1a–1d and 2a–2d) exert cytotoxicity against Bel-7402, HL-60, KB and BGC-823, but none of them is more active than cisplatin. The results suggest that metal ions, amino acids and aliphatic N-containing ligands have effect on cytotoxicity, while the IC50 values do not show definite correlation with variation of them.

Synthesis, characterization, and cytotoxicity of complexes of palladium(II) with 1,4-diaminobutane/1,3-diaminopropane and 4-toluenesulfonyl-L-amino acid dianion

Eight new palladium(II) complexes with 4-toluenesulfonyl-L-amino acid dianion and 1,4-dab/1,3-dap, [Pd(1,4-dab)(TsglyNO)] · H2O (1), [Pd(1,4-dab)(TsvalNO)] (2), [Pd(1,4-dab)(TsleuNO)] (3), [Pd(1,4-dab)(TsileNO)] (4), [Pd(1,4-dab)(TsserNO)] · 0.5H2O (5), [Pd(1,4-dab)(TspheNO)] · 0.5H2O (6), [Pd(1,4-dab)(TsthrNO)] · H2O (7), and [Pd(1,3-dap)(TsserNO)] (8), have been synthesized and characterized by elemental analysis, IR, UV, 1H NMR, and mass spectrometry. Crystal structure of 8 has been determined by X-ray diffraction. The cytotoxicities were tested by MTT assay. The results indicate the complexes exert cytotoxic effects against HL-60 and Bel-7402. The structure–activity relationship suggests that both amino acids and N-containing ligands have important effects on cytotoxicity, but the IC50 values do not show definite correlation with variation of these ligands.

New complexes of 2-hydroxy-1-naphthoic acid and X-ray crystal structure of [Pt(hna)(PPh3)2

The solid complexes [Zn(Hhna)2(H2O)2], (PPh4)2[MoO2(hna)2], [Pd(Hhna)2], [Pt(PPh3)2(hna)], [Pd(bpy)(hna)], [Pd(phen)(hna)], [Ag(Hhna)(H2O)2] and [Ag(Hhna)(PPh3)(H2O)] (H2hna=2-hydroxy-1-naphthoic acid) were prepared and characterized by IR, UV–vis, 1H NMR, 13C NMR, 31P NMR and mass spectrometry, and by elemental analysis and thermal measurements. 2-Hydroxy-1-naphthoic acid coordinates the metal ions in either binegative or mononegative bidentate manner through the deprotonated hydroxy and the deprotonated carboxylate oxygen or the carboxylato oxygen atoms. The crystal structure of [Pt(hna)(PPh3)2] has been determined, the Pt(II) center displays a square-planar geometry through the binegative bidentate 2-hydroxy-1-naphthoic acid dianion.

Unusual structure of new dimethylmalonate coordination polymer with strontium atoms and VO2+ fragments

A reaction of vanadyl sulfate VOSO4·3H2O with dimethylmalonic acid strontium salt led to the coordination polymer {Sr(H2O)8[VO(Me2mal)2]}n (1, Me2mal is the dimethylmalonic acid dianion), in which the carboxylate dianions did not form chelate metallocycles with the vanadyl ions. The complex was studied by ESR spectroscopy. The compound 1 exhibited weak spin-spin exchange interactions of ferromagnetic type between the VIV atoms.

Synthesis, characterization, and cytotoxicity of complexes of platinum(II) with 2,2′-bipyridine and N-benzoyl-L-amino acid dianion

Four new platinum(II) complexes (1–4) with N-benzoyl-L-amino acid and bipy were synthesized and characterized by elemental analysis, IR, UV, 1H NMR, and mass spectra. The crystal structure of 1 was determined by X-ray diffraction analysis. Cytotoxicities were measured by MTT and SRB assays. Complexes 1–4 exert cytotoxicity with selectivity against HL-60, Bel-7402, BGC-823, and KB cell lines. This suggests that amino acids and acylated groups have important effects on cytotoxicity; the cytotoxicity is also related to the species of tumor cells, but the IC50 values do not show definite correlation with the variation of amino acids and acylated groups.

Synthesis, characterization, and biological activity of five new mixed-ligand palladium(II) complexes with ethylenediamine and 4-toluenesulfonyl-L-amino acid dianion

Five new palladium(II) complexes with 4-toluenesulfonyl-L-amino acid dianion and en, [Pd(en)(TsserNO)] (1), [Pd(en)(TsglyNO)] (2), [Pd(en)(TsalaNO)] · 1.5H2O (3), [Pd(en)(TsleuNO)] · H2O (4), and [Pd(en)(TspheNO)] · 2H2O (5), have been synthesized and characterized by elemental analysis, IR, UV, 1H NMR, and mass spectrometry. Crystal structure of 1 has been determined by X-ray diffraction analysis. The cytotoxicity was tested by MTT and SRB assays. The results indicate 1–5 exert cytotoxic effects against HL-60, Bel-7402, BGC-823, and KB cell lines and 5 displays the best cytotoxicity. The structure–activity relationships suggest that both amino acid and N-containing ligands have important effects on cytotoxicity.

Synthesis and characterization of two copper(II) compounds with xanthurenic acid

Xanthurenic acid (8-hydroxy-4-oxo-1H-quinoline-2-carboxylic acid) is a well-known tryptophan metabolite involved in many biological processes. Metal ions bonded to xanthurenic acid can change its biological activity. The copper(II) compounds [Cu(Xan)(H2O)2] and [Cu(Xan)(H2O)2]H2O (Xan2− = xanthurenic acid dianion) were synthesized and characterized by single crystal X-ray diffraction, IR spectroscopy, thermal and elemental analysis. In both compounds, xanthurenic acid acts as a tridentate ligand forming a neutral mononuclear complex of square-pyramidal geometry with two water molecules. Neighboring molecules are linked together along the b axis by intermolecular hydrogen bonds. In the second complex, a molecule of water of crystallization was found in the asymmetric unit. The antioxidant activities of the compounds were investigated with the 2,2′-diphenyl-1-picrylhydrazyl and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) methods. Using the former reagent both copper(II) compounds showed higher antioxidant activities than H2Xan, but with the latter method the free ligand and the prepared compounds did not show any significant difference. .

Synthesis, characterization and cytotoxicity of mixed-ligand complexes of palladium(II) with 2, 2′-biquinoline/1, 4-diaminobutane and 4-toluenesulfonyl-L-amino acid dianion

Seven new palladium(II) complexes (1–7) with 4-toluenesulfonyl-L-amino acid dianion and 2, 2′-biquinoline (bqu)/1,4-diaminobutane (dab) have been synthesized and characterized by elemental analysis, IR, 1H NMR, and mass spectra techniques. Crystal structure of the complex (7) has been determined by X-ray diffraction analysis. The cytotoxicity was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and sulforhodamine B (SRB) assays. The results indicate that the complexes exert cytotoxic effects with selectivity against tested carcinoma cell lines, but their cytotoxicity is less than that of cisplatin. It suggests that all the amino acids, N-containing ligands and metal ions have important effect on cytotoxicity, but the IC50 values do not show definite correlation with variation of amino acids, N-containing ligands and metal ions, the cytotoxicity of complexes is related to tumor cell species.

Synthesis, characterization, and cytotoxicity of mixed-ligand complexes of platinum(II) with 2,2′-bipyridine and 4-toluenesulfonyl-L-amino acid dianion

Five new platinum(II) complexes (1–5) with 4-toluenesulfonyl-L-amino acid dianion and 2,2′-bipyridine (bipy) have been synthesized and characterized by elemental analysis, IR, UV, 1H-NMR, 13C-NMR, and mass spectra. The crystal structure of 1 has been determined by X-ray diffraction analysis. Cytotoxicity was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and sulforhodamine B (SRB) assays. The results indicate that 1–5 exert cytotoxic effects with selectivity against tested carcinoma cell lines; 5 displays better cytotoxicity against BGC-823, Bel-7402, and KB cell lines, while 1 has better cytotoxicity against KB cell line. The 4-toluenesulfonyl- L-amino acid dianions have important effects on cytotoxicity; when 4-toluenesulfonyl-L-amino acid dianions are 4-toluenesulfonyl-L-glycine and 4-toluenesulfonyl-L-phenylalanine, the complexes show better cytotoxicity.

Preparation, crystal structure and magnetic properties of Ni 2(dpa) 2(pyz)(H 2O) 4

A Ni(II)-based dimer structure, Ni 2(dpa) 2(pyz)(H 2O) 4 (dpa = 2,6-pyridine dicarboxylic acid dianion, pyz: pyrazine), has been prepared using hydrothermal synthesis and the solid-state magnetic properties have been evaluated. In the dimeric structure, the planar tridentate 2,6-pyridine dicarboxylic acid dianion coordinates to a Ni(II) ion in a meridional fashion and defines the equatorial plane of the complex. The fourth equatorial coordination site is then occupied by a pyrazine molecule that functions as a linear bidentate ligand bridging two Ni(II) complexes to form a dimer. The axial positions of each Ni(II) complex are occupied by two water molecules to form a distorted octahedral geometry. Susceptibility and magnetization measurements show that both intra-dimer and inter-dimer exchange interactions are weakly antiferromagnetic. The fitting of the magnetic data also indicates the existence of a large axial zero-field splitting term that contributes to the small magnetization even under high fields.

Meta-Substituted benzamide oligomers that complex mono-, di- and tricarboxylates: folding-induced selectivity and chirality

meta-Substituted arylamide trimer, pentamer and heptamer have been prepared from simple benzene-1,3-diamine, benzene-1,3-dicarboxylic acid, and 3-aminobenzoic acid units. 2D NOESY (1)H NMR experiments reveal that these flexible oligomers form folded conformations to complex di- and tricarboxylate anions of varying sizes and shapes in DMSO of high polarity, which is driven by multiple intermolecular N-H···O=C and C-H···O=C hydrogen-bonds between the amide and aromatic hydrogens of the oligomers and the carboxylate oxygens of the anions. Generally, tricarboxylate anions display an increased binding affinity compared with the dicarboxylate anions and the complexes formed by 1,3-benzenedicarboxylate anion are more stable than those formed by 1,2- or 1,4-benzenedicarboxylate anions. Circular dichroism experiments show that chiral glutamic acid dianion can induce the oligomers to produce chiral bias, leading to the formation of chiral supramolecular complexes.

Synthesis, characterization and cytotoxicity of mixed-ligand complexes of palladium(II) with aromatic diimine and 4-toluenesulfonyl- l-amino acid dianion

Eight new palladium(II) complexes ( 1a– 2d) with 4-toluenesulfonyl- l-amino acid dianion and diimine (bipy and phen) have been synthesized and characterized by elemental analysis, IR, UV, 1H NMR, 13C NMR and mass spectra techniques. Crystal structure of the complex ( 2d) has been determined by X-ray diffraction analysis. The cytotoxicity was tested by MTT and SRB assays. The results indicate that the complexes ( 1a– 2d) have selectivity against tested carcinoma cell lines. The complex ( 2c) has the best cytotoxicity among the eight complexes, moreover its cytotoxicity is better than that of cisplatin against BGC-823, Bel-7402 and KB cell lines. It suggests that both aromatic diimine and 4-toluenesulfonyl- l-amino acid have important effect on cytotoxicity.

Multinuclear nuclear magnetic resonance and density functional theoretical studies on the structure of bisperoxovanadium complexes with bidentate donors

Solid state and solution 51V and 13C NMR studies on four fundamental bisperoxovanadium complexes containing bidendate donor ligands were reported, together with DFT calculations of structural and NMR parameters. The 51V solid-state NMR characterization of the four complexes with [VO(O 2) 2L] n − anion {abbr. bpVL, where L = oxalic acid dianion (ox), pyridine-2-carboxylic acid (pic), bipyridine (bipy), and 1,10-phenanthroline (phen)} show that the ligands have a significant effect on the electric-field gradient tensor, with the quadrupolar coupling constant ranging from 4.0 to 5.8 MHz. The experimental and theoretical results suggest that the vanadium center of bpVpic, bpVphen and bpVbipy in solid state and aqueous solution are all seven-coordinated except that bpVox is six-coordinated in aqueous solution. The steric space hindrance of the organic ligands and the bonding between vanadium with the coordination influences the activity of bpVL complexes.

ChemInform Abstract: Pyruvic Acid Dimethylhydrazone. A Synthetic Equivalent of the Pyruvic Acid Dianion.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Inhibition of Hsp90 with Resorcylic Acid Macrolactones: Synthesis and Binding Studies

A series of resorcylic acid macrolactones, analogues of the natural product radicicol has been prepared by chemical synthesis, and evaluated as inhibitors of heat shock protein 90 (Hsp90), an emerging attractive target for novel cancer therapeutic agents. The synthesis involves acylation of an ortho-toluic acid dianion, esterification, followed by a ring-closing metathesis to form the macrocycle. Subsequent manipulation of the protected hydroxymethyl side chain allows access to a range of new analogues following deprotection of the two phenolic groups. Co-crystallization of one of the new macrolactones with the N-terminal domain of yeast Hsp90 confirms that it binds in a similar way to the natural product radicicol and to our previous synthetic analogues, but that the introduction of the additional hydroxymethyl substituent appears to result in an unexpected change in conformation of the macrocyclic ring. As a result of this conformational change, the compounds bound less favorably to Hsp90.

Bis(2-{[3-methyl-4-(2,2,2-trifluoro-eth-oxy)-2-pyrid-yl]methyl-sulfan-yl}-1H,3H-benzimidazolium) 2,5-dichloro-3,6-dioxocyclo-hexa-1,4-diene-1,4-diolate.

The title salt, 2C16H15F3N3OS+·C6Cl2O4 2−, is composed of two independent cations of a lansoprazole {systematic name 2-([3-methyl-4-(2,2,2-trifluoroethoxy)pyridin-2-yl]methylsulfinyl)-1H-benzo[d]imidazole} inter­mediate and a dianion of chloranilic acid. In the cations of the lansoprazole inter­mediate, the dihedral angles between the least-squares planes of the pyridine and benzimidazole rings are 11.1 (6) and 13.1 (5)°, respectively. The dihedral angles between the mean plane of the benzene ring in the chloranilic acid dianion and the pryidine and benzimidazole rings of the two lansoprazole inter­mediate groups are 71.8 (1)/80.5 (7) and 74.2 (4)/74.8 (6)°. In addition to ionic bond inter­actions, the lansoprazole inter­mediate and chloranilic ions are connected by strong N—H⋯O hydrogen bonds, which produce a set of extended O—H⋯O—H⋯O—H chains along the b axis in the (011) plane. In addition, weak C—H⋯O, C—H⋯F, N—H⋯Cl and π–π [centroid–centroid distances = 3.5631 (15), 3.8187 (13), 3.7434 (17) and 3.842 (2) Å] inter­molecular inter­actions are observed, which contribute to crystal packing stability.

Mixed-ligand chromium(III)-oxalate-pirydinedicarboxylate complexes: potential biochromium sources: kinetic studies in NaOH solutions and effect on 3T3 fibroblasts proliferation

Base hydrolysis of [Cr(ox)2(pda)]3− (where pda is N,O-bonded 2,4- and 2,5- pyridinedicarboxylic acid dianion) causes successive ligand dissociation and leads to formation of a mixture of oligomeric chromium(III) species, known as chromates(III). The main reaction path proceeds through [Cr(ox)(pda)(OH)2]3− and [Cr(pda)(OH)4]3− complexes. The kinetics of the first oxalate dissociation was studied spectrophotometrically, within the lower energy d–d band region, at 0.4–1.0 M NaOH. The character of spectroscopic changes was consistent with a consecutive reaction model, where the chelate-ring opening and the one-end bonded oxalato liberation are the first and the second reaction stages. The pseudo-first order rate constants (kobs0 and kobs1) were calculated using SPECFIT software for an A → B → C reaction pattern. Additionally, kinetics of base hydrolysis of [Cr(ox)3]3− were studied. The calculated rate constants were independent of [OH−]. Kinetic parameters for the chelate-ring opening and the first oxalate dissociation were determined. Effect of the [Cr(ox)2(pda)]3− and [Cr(2,4-pda)3]3− complexes on 3T3 fibroblasts proliferation was studied. The results manifested low cytotoxicity of these complexes, which makes them promising candidates for dietary supplements.

A systematic density functional and wavefunction-based study on dicarboxyl dianions −O2C–R–CO2 − with R = C2, C2X2, C2X4, and C6X4 (X = H, F)

The possible existence of the gas phase cis- and trans-maleate, i.e. completely deprotonated maleic acid (O2C–CΗ=CΗ–CO2)2–, is investigated by density functional (B3LYP) and ab-initio quantum chemical methods (MP2, CCSD(T)) using large basis sets. The calculations reveal that only the trans-isomer is Coulomb stable with respect to electron loss. The results are compared to other previously investigated dicarboxylate dianions of the general form −O2C–R–CO2 − with R = C2, C2X2, C2X4, and C6X4 (X = H, F). Fluorine substitution on the carbon framework helps to stabilize these doubly charged systems, and we predict that all of the aromatic fluorine substituted dicarboxylate dianions are Coulomb stable in the gas phase. Only the highest levels of theory reveal the slight stabilization of both the succinate dianion and the ortho-isomer of the phthalic acid dianion in unprecedented agreement with experiments.