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Journal of Organometallic Chemistry 12/2012; 721-722:144-147. · 2.38 Impact Factor
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Journal of Organometallic Chemistry 12/2012; 721-722:186-189. · 2.38 Impact Factor
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ABSTRACT: A dimeric Cu(II) complex [Cu(μ(2)-hep)(hep-H)](2)·2ClO(4) (1) containing bidentate (hep-H=2-(2-hydroxyethyl)pyridine) ligand was synthesized and characterized by single crystal X-ray diffraction studies. Each Cu-ion in 1 is in a distorted square pyramidal geometry. Further 1 along with silver nanoparticles (SNPs) have been used as modifier in the construction of a biomimetic sensor (1-SNP-GCPE) for determining certain catecholamines viz., dopamine (DA), levodopa (l-Dopa), epinephrine (EP) and norepinephrine (NE) using cyclic voltammetry, chronocoulometry, electrochemical impedance spectroscopy and adsorptive stripping square wave voltammetry (AdSSWV). Finally, the catalytic properties of the sensor were characterized by chronoamperometry. Employing AdSSWV, the calibration curves showed linear response ranging between 10(-6) and 10(-9)M for all the four analytes with detection limits (S/N=3) of 8.52×10(-10)M, 2.41×10(-9)M, 3.96×10(-10)M and 3.54×10(-10)M for DA, l-Dopa, EP and NE respectively. The lifetime of the biomimetic sensor was 3 months at room temperature. The prepared modified electrode shows several advantages such as simple preparation method, high sensitivity, high stability, ease of preparation and regeneration of the electrode surface by simple polishing along with excellent reproducibility. The method has been applied for the selective and precise analysis of DA, l-Dopa, EP and NE in pharmaceutical formulations, urine and blood serum samples.
Biosensors & bioelectronics 07/2012; 39(1):124-32. · 5.43 Impact Factor
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ABSTRACT: [Zr(OPr(i))(4)·Pr(i)OH] reacts with [HOSi(O(t)Bu)(3)] in anhydrous benzene in 1:1 and 1:2 molar ratios to afford alkoxy zirconosiloxane precursors of the types [Zr(OPr(i))(3){OSi(O(t)Bu)(3)}] (A) and [Zr(OPr(i))(2){OSi(O(t)Bu)(3)}(2)] (B), respectively. Further reactions of A or B with glycols in 1:1 molar ratio afforded six chemically modified precursors of the types [Zr(OPr(i))(OGO){OSi(O(t)Bu)(3)}] (1A-3A) and [Zr(OGO){OSi(O(t)Bu)(3)}(2)] (1B-3B), respectively [where G = (-CH(2)-)(2) (1A, 1B); (-CH(2)-)(3) (2A, 2B) and (-CH(2)CH(2)CH(CH(3)-)} (3A, 3B)]. The precursors A and B are viscous liquids, which solidify on ageing whereas the other products are all solids, soluble in common organic solvents. These were characterized by elemental analyses, molecular weight measurements, FAB mass, FTIR, (1)H, (13)C and (29)Si-NMR studies. Cryoscopic molecular weight measurements of all the products, as well as the FAB mass studies of 3A and 3B, indicate their monomeric nature. However, FAB mass spectrum of the solidified B suggests that it exists in dimeric form. Single crystal structure analysis of [Zr{OSi(O(t)Bu)(3)}(4)(H(2)O)(2)]·2H(2)O (3b) (R(fac) = 11.9%) as well as that of corresponding better quality crystals of [Ti(O(t)Bu){OSi(O(t)Bu)(3)}(3)] (4) (R(fac) = 5.97%) indicate the presence of a M-O-Si bond. TG analyses of 3A, B, and 3B indicate the formation of zirconia-silica materials of the type ZrO(2)·SiO(2) from 3A and ZrO(2)·2SiO(2) from B or 3B at low decomposition temperatures (≤200 °C). The desired homogenous nano-sized zirconia-silica materials [ZrO(2)·nSiO(2)] have been obtained easily from the precursors A and B as well as from the glycol modified precursors 3A and 3B by hydrolytic sol-gel process in organic media without using any acid or base catalyst, and these were characterized by powder XRD patterns, SEM images, EDX analyses and IR spectroscopy.
Dalton Transactions 06/2012; 41(31):9439-50. · 3.84 Impact Factor
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ABSTRACT: In the presence of a catalytic amount of Fe(CO)(5), terminal acetylenes, isocyanates and CO undergo [2 + 2 + 1] cyclization to form substituted maleimides and hydantoins; when internal alkynes are used, exclusive maleimide formation is observed. While the maleimides can be obtained as the major products, in up to 90% yield, when the reaction is carried out in CO atmosphere, in absence of CO, the hydantoins are formed in up to 87% yield. Formation of maleimides has been shown to occur via the formation of a ferrole intermediate, whereas the hydantoins are proposed to form through successive insertion of isocyanate into the iron-acetylide bond. All compounds were characterized by spectroscopic methods and molecular structures of some compounds were established by single crystal X-ray diffraction method.
Dalton Transactions 03/2012; 41(16):5045-54. · 3.84 Impact Factor
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ABSTRACT: Thermal reaction between PhC≡CI and powd. Te afforded a mixt. of the 1,3-ditellurofulvene compds. (E)-4-iodo-2-(iodo)(phenyl)methylene-5-phenyl-1,3-ditellurole (1) and (E)-1,1,4-triiodo-2-(iodo)(phenyl)methylene-5-phenyl-1,3-ditellurole (2), which was subsequently reduced to (Z)-4-iodo-2-(iodo)(phenyl)methylene-5-phenyl-1,3-ditellurole (3). Formation of 1 and 3 as the thermodynamically most stable products was rationalized using d. functional theory (DFT) calcns. The mol. structures of 1-3 were established crystallog. In the solid state the coordination sphere of both Te atoms in 2 is extended by weak intermol. Te···π interactions with the solvate mol. of toluene which completes the pseudo-trigonal bipyramidal coordination geometry around each Te atom and assembles 2 into chains along the crystallog. c-axis. [on SciFinder(R)]
Journal of Organometallic Chemistry. 01/2012; 696:496-503.
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ABSTRACT: Coupling reaction of 1-ferrocenyl-4-phenyl-1,3-butadiyne and bis(trimethylsilylethynyl)ferrocene with iron pentacarbonyl Pradeep Mathur,a, b Radhe Shyam Ji,a Amrendra K. Singh a and Shaikh M. Mobinb aDepartment of Chem., bNational Single Crystal X-ray Diffraction Facility, Indian Institute of Technol. Bombay, Mumbai, 400076, India E-mail: mathur@iitb.ac.in, radheshyamji@iitb.ac.in Reactions of ferrocenyl substituted alkynes with cluster carbonyls are of considerable interest due to their applications like multielectron redox catalysts[1, 2] and electron storage devices [3].Photochem. reaction of 1-ferrocenyl -4-phenyl-1,3-butadiyne and Fe(CO)5 under argon led to the formation of six different products. [Fe(CO)2{η2:η2-PhCCCC(Fc)C(CCPh)C(Fc)Fe(CO)3}-μ-CO] (1), [Fe2(CO)6{μ-η1:η1:η2:η2-PhCCCC(Fc) -C(O) -C(Fc)CCCPh}] (2), [Fe2(CO)6{μ-η1:η1:η2:η2-FcCC(CCPh) -C(O) -C(Fc)CCCPh}] (3), [Fe2(CO)6{μ-η1: η1:η2:η2-FcCCCC(Fc)-C(O)-C(Fc)CCCPh}](4), [Fe(CO)3{μ-η2:η2- [FcCC(C
01/2011
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ABSTRACT: The oxyanions (NO3-, CO32-) and phenoxyacetate (PhOAc-) bridged three 1-dimensional-coordination polymeric chains, {[Cu2(μ-hep)2(μ-NO3)]2}n (1), {[Cu2(μ-hep)2(H2O)2]·2H2O(μ-CO3)}n (3) and {[Cu2(μ-hep)2(μ-PhOAc-)]2}n (2) (hep-H = 2-(2-hydroxyethyl)pyridine) were synthesized. In 1-3 the alkoxide bridged dicopper building units, [Cu(μ-hep)]2 with Cu2O2 core, are linked via the resp. anions. Detailed structural anal. reveals that in 1 or 2, two units of NO3- (1) or PhOAc- (2), resp., bind with the four Cu ions in two adjacent alkoxide bridged dimeric units in head-to-head and tail-to-tail fashion and the same binding mode continues along the polymeric chain. This in effect yields a 12-membered metallacyclic ring in between two dimeric core units. However, in 3 only one CO32- group bridges the two Cu centers assocd. with the two neighboring alkoxide bridged dimeric units in head-to-tail mode which in turn forms a zigzag polymeric chain. Two coordinated and two lattice H2O mols. from two adjacen
RSC Advances. 01/2011; 1:893-902.
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ABSTRACT: Reactions of [Ti(OPri)4] with various oximes, in anhyd. refluxing benzene yielded [Ti{OPri}4-n{L}n], where, n = 1-4 and LH = Me2C:NOH (1-4), C9H16C:NOH (5-8) and C9H18C:NOH (9-12). The compds. were characterized by elemental analyses, mol. wt. measurements, FAB-mass, FTIR and NMR (1H, 13C{1H}) spectral studies. The FAB-mass spectra of mono- (1), and di- (2), (6), (10) substituted products indicate their dimeric nature and that of tri- (3) and tetra- (4), (8) substituted derivs. suggest their monomeric nature. Crystal and mol. structure of [Ti{ONC10H16}4·2CH2Cl2] (8A) suggests that the oximato ligands bind the metal in a dihapto η2-(N, O) manner, giving an eight coordinated species. Thermogravimetric curves of (3), (6) and (10) exhibit multi-step decompn. with the formation of TiO2 as the final product in each case, at 900°. Low temp. (∼600°) sol-gel transformations of (2), (3), (4), (6), (7) and (8) yielded nano-sized titania (a), (b), (c), (d), (e) and (f), resp. Formation of anatase phase
Polyhedron. 01/2011; 30:821-831.
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ABSTRACT: Diglycine perchlorate (DGPCl), a new 2:1 adduct formed between glycine and perchloric acid was obtained and studied using DSC and single crystal x-ray diffraction. DGPCl undergoes a reversible first-order phase transition at 261.5 K. The crystal structures at 150 and 293 K are triclinic, space group P-1, Z = 2, suggesting the first-order phase transition to be an isostructural phase transition. The DGPCl crystal consists of five glycinium-monoprotonated glycinium dimers and five perchlorate anions in an asym. unit. The glycine moieties in the glycinium-monoprotonated glycinium dimers are nonplanar. Two types of hydrogen bonds are present in the crystal, strong O-H···O hydrogen bonds and a weak N-H···O hydrogen bonds. The short, strong O-H···O hydrogen bond connects the glycinium ion and mono protonated glycinium ion. In four of the dimers, the O-H and H···O bond lengths are different, indicating the hydrogen atom to be located more close to the monoprotonated glycinium ion. However,
Journal of Chemical Crystallography. 01/2011; 41:147-154.
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ABSTRACT: The title compd., C30H28Cl2N4O6Zn, dichlorobis(ethylanthranilatonicotinamide)zinc(II) crystd. in a triclinic space group, P‾1, with a 7.787(3), b 13.468(1), c 15.735(1), α 110.25(1), β 95.11(1), γ 99.32(1)°and Z = 2, with the whole mol. being the asym. unit. In this compd., zinc is bound to two ethylanthranilatonicotinamide (EAN) ligands and two chloride ligands in a distorted tetrahedral configuration. The nitrogen of the nicotinamide ring participates in bonding with zinc through its lone pair while the anthranilate nitrogen remains free. In one of the two EAN ligands, the anthranilate and nicotinamide groups are nearly coplanar while in the other, the angle between the two is ∼35.5°. The complex shows three hydrogen bonds, two being C-H···O bonds and the other being C-H···Cl bond. The amidic N-H groups do not participate in hydrogen bond formation as they are buried in the core structure and are not accessible for other groups for assocn. Both the C-H···O bonds occur from C-H
Journal of Chemical Crystallography. 01/2011; 41:801-805.
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ABSTRACT: Reactions of HgX(2) (X = Cl(-), Br(-), l(-)) with the ligand hep-H (hep-H = 2-(2-hydroxyethyl)pyridine) in methanol at 298 K result in 1D-polymeric chains of [(X)Hg(mu-X)(2)(hep-H)](infinity), 1-3, respectively, where hep-H binds to the Hg(ii) ions in a monodentate fashion exclusively with the pyridine nitrogen donor and the suitably ortho-positioned -(CH(2))(2)OH group of hep-H remains pendant. The packing diagrams of 1-3 exhibit extensive intramolecular and intermolecular hydrogen bonding interactions leading to hydrogen bonded 2D network arrangement in each case. Though the single crystal of either 2 (X = Br) or 3 (X = I) loses crystallinity upon heating, the single crystal of 1 selectively transforms to a 2D-polymeric network, 4 on heating at 383 K for 1.5 h. The polymeric 4 consists of central dimeric [Hg(mu(3)-Cl)(hep-H)Cl](2) units, which are covalently linked with the upper and lower layers of [-(mu-Cl)(2)-Hg-(mu-Cl)(2)-Hg(mu-Cl)(2)-](n). The packing diagram of 4 reveals the presence of O-H-Cl and C-H-Cl hydrogen bonding interactions which in effect yields hydrogen bonded 3D-network. Remarkably, the single crystals of 4 convert back to the single crystals of parent 1 on standing at 298 K for three days.
Dalton Transactions 10/2010; 39(37):8698-705. · 3.84 Impact Factor
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ABSTRACT: A new dimeric Cu(II) complex [Cu(mu(2)-hep)(hep-H)](2).2PF(6) (1) containing a bidentate (hep-H = 2-(2-hydroxyethyl)pyridine) ligand was synthesized and characterized by single crystal X-ray diffraction studies. Each Cu ion in 1 is in a distorted square pyramidal geometry. Further 1 is used as a modifier in the construction of a biomimetic sensor for determining phenols [phenol (Phe), resorcinol (Res), hydroquinone (HQ), and catechol (Cat)] in phosphate buffer by using cyclic voltammetry (CV), chronocoulometry, electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and square wave voltammetry (SWV). DPV has been proposed for trace determination of Phe and Res while SWV for HQ and Cat. The method has been applied for the selective and precise analysis of Phe in commercial injections, Res in hair coloring agents, HQ in photographic developers and cosmetics, and Cat in tea samples and guarana tablets. The calibration curves showed a linear response ranging between 10(-6) and 10(-8) M for all four of the analytes with detection limits (3sigma) of 1.04 x 10(-8), 2.31 x 10(-8), 1.54 x 10(-8), and 0.86 x 10(-8) M for Phe, Res, HQ, and Cat, respectively. The lifetime of the biomimetic sensor was 200 days at room temperature (at least 750 determinations). The catalytic properties of 1-CPE were characterized by chronoamperometry and were found to be in good agreement with Michaelis-Menten kinetics.
Analytical Chemistry 07/2010; 82(14):5983-92. · 5.86 Impact Factor
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ABSTRACT: The single crystals of discrete hydrated [(OAc)Cu(mu-hep)(2)Cu(OAc)].2H(2)O (.2H(2)O) and [(OAc)Cu(mu-hep)(2) Cu(O(n)Pr)].2H(2)O (.2H(2)O) (the lattice H(2)O molecules exist as a tetrameric water cluster, hep-H = 2-(2-hydroxyethyl)pyridine), OAc(-) = acetate and O(n)Pr(-) = n-propionate) undergo single-crystal to single-crystal (SCSC) transformations to the dehydrated and , respectively, under the influence of heat. The reverse SCSC processes of /-->.2H(2)O/.2H(2)O involving the regeneration of the lattice water tetramers take place on exposure of / to water vapour. However, the blue single crystal of discrete hydrated [(O(n)Pr)Cu(mu-hep)(2)Cu(O(n)Pr)].2H(2)O (.2H(2)O), incorporating the two bulkier O(n)Pr(-) terminal bidentate ligands, irreversibly converts to the green single crystal of a unique discrete tetrameric [Cu(4)(mu(3)hep)(2)(mu-hep)(2)(mu-O(n)Pr)(2)(O(n)Pr)(2)] () with double open cubane core either by heating or by a simple vapour diffusion technique via the breaking and forming of multiple covalent bonds.
Dalton Transactions 02/2010; 39(6):1447-9. · 3.84 Impact Factor
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ABSTRACT: Reactions of HgX2 (X = Cl-, Br-, I-) with the ligand hep-H (hep-H = 2-(2-hydroxyethyl)pyridine) in MeOH at 298 K result in 1-dimensional-polymeric chains of [(X)Hg(μ-X)2(hep-H)]∞, (1-3), resp., where hep-H binds to the Hg(II) ions in a monodentate fashion exclusively with the pyridine N donor and the suitably ortho-positioned -(CH2)2OH group of hep-H remains pendant. The packing diagrams of 1-3 exhibit extensive intramol. and intermol. H bonding interactions leading to H bonded 2-dimensional network arrangement in each case. Though the single crystal of either 2 (X = Br) or 3 (X = I) loses crystallinity upon heating, the single crystal of 1 selectively transforms to a 2-dimensional-polymeric network, 4 on heating at 383 K for 1.5 h. The polymeric 4 consists of central dimeric [Hg(μ3-Cl)(hep-H)Cl]2 units, which are covalently linked with the upper and lower layers of [-(μ-Cl)2-Hg-(μ-Cl)2-Hg(μ-Cl)2-]n. The packing diagram of 4 reveals O-H-Cl and C-H-Cl H bonding interactions which in effect yi
Dalton Transactions. 01/2010; 39:8698-8705.
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ABSTRACT: Photolysis of a hexane soln. of ferrocenylacetylene and S powder in presence of Cr(CO)6 gave 2,6-diferrocenyldithiine and 2,5-diferrocenylthiophene. Similar reactions with Mo(CO)6 or W(CO)6 gave only the thiophene deriv. Formation of ferrocenyl-substituted thioketone complexes was obsd. in the reaction of ferrocenylacetylene with H2O and S, in presence of W(CO)6. Use of D2O confirmed H2O as source of protons for the conversion of acetylenic CH to CH3.
Journal of Organometallic Chemistry 01/2010; 695:950-954. · 2.38 Impact Factor
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ABSTRACT: Photolysis of a hexane soln. contg. iron pentacarbonyl, 1-ferrocenyl-4-phenyl-1,3-butadiyne at low temp. yields six new products: [Fe(CO)2{η2:η2-PhC≡CCC(Fc)C(C≡CPh)C(Fc)Fe(CO)3}-μ-CO] (1), [Fe2(CO)6{μ-η1:η1:η2:η2-PhC≡CCC(Fc)-C(O)-C(Fc)CC≡CPh}] (2), [Fe2(CO)6{μ-η1:η1:η2:η2-FcCC(C≡C Ph)-C(O)-C(Fc)CC≡CPh}] (3), [Fe2(CO)6{μ-η1:η1:η2:η2-FcC≡CCC(Fc)-C(O)-C(Fc)CC≡CPh}] (4), [Fe(CO)3{μ-η2:η2-FcCC(C≡CPh)C(C≡CPh)C(Fc)}CO] (5) and [Fe(CO)3{μ-η2:η2-FcCC(C≡CPh)C(C≡CPh)C(Fc)}CO] (6) formed by coupling of acetylenic moieties with CO insertion on metal carbonyl support. In presence of CO, formation of another new product 2,5-bis(ferrocenyl)-3,6-bis(tetracarbonylphenylmaleoyliron)quinone (7) was obsd. which on further reaction with ferrocenylacetyene gave the quinone, 2,5-bis(ferrocenyl)-3,6-bis(ethynylphenyl)quinone (8). Structures of 1-5 and 8 were established crystallog. [on SciFinder(R)]
Journal of Organometallic Chemistry 01/2010; 695:1986-1992. · 2.38 Impact Factor
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ABSTRACT: A facile, one pot, high yield synthesis of α,β-vinylester and alkoxy substituted γ-lactones has been achieved by the photochem. reaction of terminal acetylene with alc. and carbon monoxide in presence of iron pentacarbonyl as a catalyst. The selectivity of the compds. depends on the time of photolysis of the reaction as well as the solvent used. A stable reaction intermediate ferrole was isolated, and further photolysis with alcs., resulted in the formation of α,β-vinylester. All the compds. were fully characterised by spectroscopic methods and some of the mol. structures were established crystallog. [on SciFinder(R)]
Journal of Organometallic Chemistry 01/2010; 695:2687-2694. · 2.38 Impact Factor
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ABSTRACT: The symmetric dimeric complex [Cu(mu(2)-hep)(TFA)(H(2)O)](2) (1) has been synthesized from 2-(2-hydroxyethyl)pyridine (hep-H), trifluoroacetic acid (TFA-H), and copper acetate in a 95:5 (v/v) MeOH-H(2)O mixture at 298 K. Each Cu(II) ion in 1 is linked with two mu(2)-alcoholic oxygen atoms and one pyridine nitrogen atom of hep, and the other two coordination sites are occupied by the oxygen donors of TFA and H(2)O. At room temperature, the blue single crystals of 1 transform to the green single crystals of a tetrameric complex, [Cu(4)(mu(3)-hep)(2)(mu(2)-hep)(2)(mu(2)-TFA)(2)(TFA)(2)] (2), in presence of alcoholic vapor. The facile single crystal-to-single crystal (SCSC) transformation of 1 to 2 is accompanied by the removal of coordinated H(2)O molecules in 1 and concomitant formation of four new covalent bonds, two Cu-O(mu(3)-hep) and two Cu-O(mu(2)-TFA). The SCSC transformation of 1 to 2 is selective to the alcoholic vapor; the exposure of single crystals of 1 to heat or light or in vacuum has resulted in an immediate loss in crystallinity.
Inorganic Chemistry 06/2009; 48(11):4652-4. · 4.60 Impact Factor
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ABSTRACT: Photolysis of a hexane soln. contg. Fe(CO)5 and CS2 leads to desulfurization and formation of a novel cluster [{Fe2(CO)6}2(μ-C2S3)]. Its mol. structure was detd. by single crystal x-ray diffraction methods and shown to consist of two distinct Fe2(CO)6 units linked by an unusual C2S3 unit. [on SciFinder(R)]
Journal of Organometallic Chemistry. 01/2009; 694:3043-3045.
