Synthesis and Structures of Polymeric Mn, Co, Cu, and Zn Complexes of 3-Diphenylamino-4-hydroxycyclobut-3-ene-1,2-dione (Diphenylaminosquarate) and of the Salt [Ni(H2O)6][(C6H5)2NC4O3]2·2H2O

Williams, Avril; Alleyne, Bert D.; Hall, Lincoln A.; White, Andrew J. P.; Williams, David J.; Thompson, Laurence K.

doi:10.1021/ic000390q

Cited by 16 publications

(16 citation statements)

References 28 publications

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“…Both bond lengths and angles are in good agreement with those of comparable hexaaquanickel complex, e.g. theophylline-7-acetate hexaaquanickel(II) tetrahydrate [8] or hexaaquanickel(II) bis(diphenyl aminosquarate) dihydrate [9]. Within the asymmetric unit, each…”

Section: Discussionsupporting

confidence: 69%

Crystal structure of hexaaquanickel(II) bis[1-(carboxylatomethyl)-1,3- benzimidazol-3-ium-3-acetato] dihydrate, [Ni(H2O)6](C11H9N2O4)2 · 2H2O

Huang¹,

Chen²

2008

Zeitschrift Für Kristallographie - New Crystal Structures

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Source of materialThe starting material 1-(carboxymethyl)-1H-benzimidazol-3-ium-3-acetate was prepared from chloroacetic acid and benzimidazole [1]. 1-(Carboxymethyl)-1H-benzimidazol-3-ium-3-acetate (0.0937 g, 0.4 mmol) was dissolved in 50% ethanol (20 ml) containing NaOH (0.0161 g, 0.4 mmol). The resulting solution was added dropwise to ahot solution of nickel dichloride hexahydrate (0.0952 g, 0.4 mmol) dissolved in the same solvent (10 ml) under continuous stirring for 3h.After filtration, the bluegreen filtrate was kept at room temperature. By slow evaporation of the solvent blue block-like crystals suitable for X-ray diffraction were obtained. Experimental detailsThe two Hatoms (H1A and H1B) were positioned geometrically and refined as riding on their parent atom O1W. The remaining H atoms were located in difference Fourier maps, and were refined with distance restraints giving DiscussionImidazole and benzimidazole carboxylic acids and their derivatives have attracted broad interest because of their functional properties such as antifilarial, antineoplastic, anthelmintic and antiviral activities [2][3][4]. In addition, these compounds are used widely as ligands in the coordination chemistry of supramolecular metal complexes, because the Na tom in the imidazole or benzimidazole ring and the Oatoms in the carboxylate groups can act as donor sites [5]. However, studies of metal complexes with these ligands as zwitterions are still rare [6,7]. In the molecular structure of the title compound the Ni II atom lies at acrystallographic inversion center and is coordinated by six O atoms from water molecules with aslightly distorted octahedral environment ( figure, top). The metal-oxygen bonds are in the range from 2.055(1) to 2.065(1) Å,the bond angles around each metal center range from 88.86(4)°to 180°. Both bond lengths and angles are in good agreement with those of comparable hexaaquanickel complex, e.g. theophylline-7-acetate hexaaquanickel(II) tetrahydrate [8] or hexaaquanickel(II) bis(diphenyl aminosquarate) dihydrate [9]. Within the asymmetric unit, each2+ cation is connected with neighboring 1-(carboxymethyl)-1,3-benzimidazol-3-ium-3-acetato anions via hydrogen bonds betweencoordinated water Oatom and the uncoordinated carboxyl Oa tom, namely O5-H5A···O4ii ,O 5 -H5B···O2, O6-H6B···O3 iv ,O7-H7A···O1 v (symmetry codes: (ii) x,y,z+1; (iv) 3-x,-y+2,-z;(v) -x+1,-y+2,-z+1). Besides, the water molecules act as hydrogen-bond donors to carboxylate Oatom as well as hydrogen-bond acceptors of coordinated water Oa toms. Thus, the relative independent components [Ni(H 2O)6] 2+ ,1-(carboxymethyl)-1,3-benzimidazol-3-ium-3-acetato anions and lattice H 2 Omolecules are assembled into two-dimensional layers parallel to (001). The non-classical hydrogen bonds (C-H···O) link adjacent layers to form athree-dimensional network (figure, bottom).

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Section: Discussionsupporting

confidence: 69%

Crystal structure of hexaaquanickel(II) bis[1-(carboxylatomethyl)-1,3- benzimidazol-3-ium-3-acetato] dihydrate, [Ni(H2O)6](C11H9N2O4)2 · 2H2O

Huang¹,

Chen²

2008

Zeitschrift Für Kristallographie - New Crystal Structures

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“…, Tb (7)]. The geometry at the lanthanide center is square antiprismatic, the metal atom being bonded to the oxygen atoms of two squarate and six aqua ligands (Figure 6).…”

Section: Lanthanide(iii) Complexes Of Squarate Ligandsmentioning

confidence: 99%

“…2 By contrast, when the (diphenylamino)squarate ligand was used, the steric effect of the out-of-plane phenyl rings prevented the hydrolysis, allowing the formation of monosubstituted squarate complexes. 3,7 This coplanarity assumes less importance in the case of the anilinosquarate ligand, where complexes with both coplanar [Ru(II) anilinosquarate] and twisted [M(II) anilinosquarate; M ) Mn, Co, Ni, Cu, Zn] relative orientations of the C 4 -and C 6 -rings, respectively, have been observed. 8,9 The electron delocalization on the C 4 -ring and the extent of electron transfer from the monosubstituted squarate ligand to the coordinated metal center are also considered to be important factors in polymer formation and have been shown to be significantly effected by the availability of lone pairs on the substituents on the C 4 -ring.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, for dialkylamino substituents, the coplanarity of the NR 2 units and the C 4 -rings seems to enhance the susceptibility of these amino groups to hydrolysis, resulting in the formation of products without monosubstituted squarate ligands, thereby defeating the object of the exercise . By contrast, when the (diphenylamino)squarate ligand was used, the steric effect of the out-of-plane phenyl rings prevented the hydrolysis, allowing the formation of monosubstituted squarate complexes. , This coplanarity assumes less importance in the case of the anilinosquarate ligand, where complexes with both coplanar [Ru(II) anilinosquarate] and twisted [M(II) anilinosquarate; M = Mn, Co, Ni, Cu, Zn] relative orientations of the C 4 - and C 6 -rings, respectively, have been observed. , The electron delocalization on the C 4 -ring and the extent of electron transfer from the monosubstituted squarate ligand to the coordinated metal center are also considered to be important factors in polymer formation and have been shown to be significantly effected by the availability of lone pairs on the substituents on the C 4 -ring. ,,− To date, however, only cases where the atom with the lone pairs is directly bonded to the C 4 -ring have been studied.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Attempted Syntheses of Lanthanide(III) Complexes of the Anisole- and Anilinosquarate Ligands

Piggot¹,

Hall²,

White³

et al. 2003

Inorg. Chem.

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The polymeric lanthanide complexes (Ln(mu-CH3OC6H5C4O3)(CH3OC6H5C4O3)2 (H2O)4.xH2O)n [Ln=La (1), Eu (2), Gd (3)], formed from the reaction of aqueous solutions of anisolesquarate and Ln(NO3)3.xH2O, are all structurally similar with only subtle differences between the lanthanum complex and the isomorphous pair of europium and gadolinium analogues. The lanthanum atom in 1 has a square antiprismatic coordination geometry comprising two pendant and two mu-1,3-bridging anisolesquarate groups and four aqua ligands. Complexes 2 and 3 have two independent metal atoms in their asymmetric units compared to one for the lanthanum complex. However, the gross structures of 1-3 are essentially the same. The asymmetric unit of the terbium complex ((CH3OC6H5C4O3)3Tb(H2O)4(mu-CH3OC6H5C4O3)(CH3OC6H5C4O3)2Tb(H2O)5).H2O (4) contains two independent binuclear units which hydrogen bond to form an extended structure very similar to those of 1-3. The ionic polymers ([Ln(mu2-C4O4)(H2O)6][C6H5NHC4O3].4H2O)n [Ln=Eu (5), Gd (6), Tb (7)] result from the incomplete hydrolysis of the anilinosquarate ion during the attempted synthesis of Eu(III), Gd(III), and Tb(III) anilinosquarate complexes. However, complete hydrolysis of the substituent is accomplished by La(III) ions, and the neutral polymer (La2(mu2-C4O4)2(mu3-C4O4)(H2O)11.2H2O)n (8) is formed. In complexes 5-7, the central lanthanide atom has a square antiprismatic geometry, being bonded to two mu-1,2-bridging squarate and six aqua ligands. Two anilinosquarate counteranions participate in second-sphere coordination via direct hydrogen bonding to aqua ligands on each metal center. These counteranions, and the included waters of crystallization, serve to link neighboring cationic polymer chains via an extensive array of O-H...O hydrogen bonds to form a 3-dimensional network. The polymeric lanthanum complex 8 contains two different metal environments, each having distorted monocapped square antiprismatic geometry. For one lanthanum atom the coordination polyhedron comprises five aqua and four squarate ligands, while for the other the polyhedron consists of six aqua and three squarate ligands; in each case one of the aqua ligands occupies the capping position. The squarate ligand exhibits two coordination modes in 8 (mu-1,2- and mu-1,3-bridging), and neighboring polymer chains are cross-linked by hydrogen bonds to form a 3-dimensional network.

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“…Recently, we reported on the electron-mediating characteristic of 3-methyl-4-hydroxycyclobut-3-ene-1,2-dione and its phenyl analog in amperometric glucose sensor [19], as part of our investigation of the suitability of these ligands as bridging groups for the mediation of electronic [18][19][20] and magnetic interactions [21][22][23][24][25][26][27] in polymeric complexes containing monosubstituted squarate ligands. In this article, we report on the electron transfer-mediating properties of the monosubstituted squarate, 3-diphenylamino-4-hydroxycyclobut-3-ene-1,2-dione (diphenylaminosquarate: Fig.…”

Section: Introductionmentioning

confidence: 99%

Electrochemistry and application of a novel monosubstituted squarate electron-transfer mediator in a glucose oxidase-doped poly(phenol) sensor

Iwuoha

Williams-Dottin

Hall

et al. 2004

Pure and Applied Chemistry

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Electrosynthetic poly(phenol) nanofilms were deposited in situ on platinum electrodes in the presence and absence of glucose oxidase. The synthesis charges and currents of the nonconducting polymer films were recorded at various applied potentials for films grown from 25-100 mM phenol concentrations. Film parameters such as the standard rate constant for film deposition, film thickness, and surface concentration of the poly(phenol) films were evaluated from the cyclic and step voltammograms of the polymerization process. A novel electron-transfer mediator consisting of monosubstituted 4-hydroxycyclobut-3-ene-1,2-dione (squarate) was used as a mediator for Pt/poly(phenol) nano-film/GOx amperometric glucose biosensors. Amperometric responses for 3-diphenylamino-4-hydroxycyclobut-3-ene-1,2-dione (diphenylaminosquarate: E°′ = of +328 mV/Ag-AgCl at pH 7.0)-mediated systems were measured by both steady-state amperometric and cyclic voltammetry. The sensor sensitivity was calculated to be 558 nA cm -2 (µM) -1 .

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Synthesis and Structures of Polymeric Mn, Co, Cu, and Zn Complexes of 3-Diphenylamino-4-hydroxycyclobut-3-ene-1,2-dione (Diphenylaminosquarate) and of the Salt [Ni(H₂O)₆][(C₆H₅)₂NC₄O₃]₂·2H₂O

Cited by 16 publications

References 28 publications

Crystal structure of hexaaquanickel(II) bis[1-(carboxylatomethyl)-1,3- benzimidazol-3-ium-3-acetato] dihydrate, [Ni(H2O)6](C11H9N2O4)2 · 2H2O

Crystal structure of hexaaquanickel(II) bis[1-(carboxylatomethyl)-1,3- benzimidazol-3-ium-3-acetato] dihydrate, [Ni(H2O)6](C11H9N2O4)2 · 2H2O

Attempted Syntheses of Lanthanide(III) Complexes of the Anisole- and Anilinosquarate Ligands

Electrochemistry and application of a novel monosubstituted squarate electron-transfer mediator in a glucose oxidase-doped poly(phenol) sensor

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