Characterization of 11-mercaptoundecanoic and 3-mercaptopropionic acids adsorbed on silver by surface-enhanced Raman scattering (original) (raw)
Related papers
Vibrational Spectroscopy, 2016
Surface-enhanced Raman scattering (SERS) spectra of squaric acid (SA) and its complex with Cu(II) ion have been obtained on silver nanoparticle (AgNP) surfaces. The spectral deconvolution of the band assigned to symmetric carbonyl stretching showed the presence of two distinct coordination modes in the surface complex on AgNP even at high concentrations of Cu(II) ion. Additionally, in the presence of Cu (II), two bands have been observed in the low wavenumber range assigned to the AgÀ ÀO and Cu(II)À ÀO stretching vibrations. An increase of the squaric acid-Cu(II) complex signal has also been shown with the increase of the cation concentration up to a molar ratio of 1:1 (SA:Cu(II)). At higher concentrations of Cu (II) ions the intensity ratio of the features assigned to the symmetric CO stretching for SAÀ ÀAg and Cu(II)-SA-Ag species was kept approximately constant. A relative population analysis suggests that an equilibrium between the species contributing to the SERS signal has been established, with the saturation of the surface with the Cu(II)-SA-Ag surface complex. The SERS analysis used here is a facile method for the detection and structural characterization of coordinated systems derived from squaric acid adsorption on SERS-active silver surfaces. 2016 Elsevier B.V. All rights reserved.
Inorganic Chemistry, 1995
The mechanism by which Cu(1) and Zn(I1) influence the decarboxylation of malonic acid derivatives has been investigated comprehensively by means of structural and kinetic studies. The air-sensitive bis(ph0sphine)copper-(I) complexes of phenylmalonic acid and its benzyl hemiester have been synthesized from 1 equiv of the acid and cuprous butyrate in the presence of phosphine ligands. As revealed by structural studies the copper(1) center is three-coordinate containing two phosphine ligands and a monodentately bound carboxylate group. On the other hand, soluble zinc(I1) phenylmalonic acid and ester derivatives were prepared from ( H B (~-P~~Z )~) Z~O~C C H~, HB(3-Phpz)? = tris(3-phenylpyrazolyl)hydroborate, and the corresponding malonic acid or hemiester. The Zn(II) complexes were all shown by X-ray crystallography to be four-coordinate with monodentately bound carboxylates. Kinetic evidence is presented herein which demonstrates that decarboxylation of malonic acid or hemiester derivatives in the presence of bis(phosphine)copper(I) or y3-HB(3-Phpz)3Zn" carboxylate salts occurs via a predissociation step involving metal-carboxylate bond rupture. Consistent with this mechanistic proposal, the rates of decarboxylation are greatly enhanced upon sequestering the metal cations with chelating nitrogen bases or upon replacing the Cu(1) or Zn(II) cations with a noninteracting counterion. Furthermore, because of the stronger Zn-0 carboxylate bonds as compared with their Cu(1)-0 analogs, the zinc carboxylates are more stable toward decarboxylation or 13C02 exchange processes. Indeed, the rates of these processes parallel the Zn-0 bond lengths with the pyrazolylhydroborato complex, which has a shorter Zn-0 bond distance than its triazacyclododecane analog, undergoing decarboxylation at a much slower rate. Crystal data for 3CuO2CC-(C~HS)(C~H~)CO~H (1): triclinic space group P1, a = 11.631(5) A, b = 12.206(4) A, c = 20.000(6) A, a = 85.91(3)", , ! ? = 89.61(3)", y = 71.24(3)", Z = 2, R = 4.20%. Crystal data for y3-HB(3-Phpz)3Zn02CCH2COOH (2): triclinic space group Pi, a = 11.935(3) A, b = 12.227(4) A, c = 12.643(5) A, a = 77.56(3)", , ! ? = 72.18(3)", y 7 73.21(2)", Z = 2, R = 7.00%. Crystal data for q3-HB(3-Phpz)3Zn02CCH2Ph: triclinic space group Pi, a = 9.884((2) A, b = 12.189(3) A, c = 15.482(2) A, a = 105.80(1)0, , ! ? = 92.46(1)", y = 90.94(2)", Z = 2, R = 8.21%. c3 Darensboure. D. J.: Loneridee. E. M.: Atnio. E. V.: Reibensuies. J. H. Inorg. Ciem. 1992, 37, 3551. (2) (a) Toussaint, 0.; Capdevielle, P.; Maumy, M. Synthesis 1986, 1029. (b) Toussaint, 0.; CGdevielle, P.; Maumy, M. Tetrahedron 1984.40, 3229. (3) Darensbourg, D. J.; Holtcamp, M. W.; Khandelwal, B.; Reibenspies, J. H. Inorg. Chem. 1993, 33, 531. (4) (a) Darensbourg, D. J.; Longridge, E. M.; Holtcamp, M. W.; Klausmeyer, K. K.; Reibenspies, J. H. J. Am. Chem. SOC. 1993, 115, 8839. (b) Darensbourg, D. J.; Longridge, E. M.; Atnip, E. V.; Reibenspies, J. H. Inorg.
Inorganica Chimica Acta, 1999
The interaction of Cu 2 + with galactaric acid leads to the formation, at acidic pH, of the complex species [CuGala] (Gala=galactaric dianion), while at physiological pH the prevailing species is [Cu(GalaH − 2 )] 2 − where the carbohydrate acts as chelating agent toward the metal ion through the carboxylic groups and the deprotonated a-hydroxylic oxygens. The crystal structures of galactaric acid (1) and of the ternary complex [CuGala(bpy)] n ·2nH 2 O (2) (bpy = 2,2%-bipyridine) are also reported. A comparison of the coordinative behavior of galactaric acid and other aldonic and alduronic acids is also discussed. (M. Saladini) 0020-1693/99/$ -see front matter © 1999 Elsevier Science S.A. All rights reserved. PII: S 0 0 2 0 -1 6 9 3 ( 9 9 ) 0 0 1 8 8 -7
Characterization of self-assembled carboxylate monolayers and multilayers at copper and silver
Explanation of dissertation format 2 PAPER I. SCANNING TUNNELING MICROSCOPY OF EVAPORATED COPPER FILMS AND COMPOSITION AND STRUCTURE OF SPONTANEOUSLY ADSORBED MONOLAYERS OF n-ALKANOIC ACIDS 3 Characterization with infrared spectroscopy 16 Scanning tunneling microscopy (STM) of the native oxide of copper 23 Proposed adsorbate structure 29 CONCLUSIONS 33 REFERENCES 34 PAPER II. SERENDIPITOUS DISCOVERY OF MULTILAYER FILMS OF SHORT CHAIN n-ALKANOIC ACIDS ASSEMBLED FROM THE GAS PHASE AT COPPER 38 INTRODUCTION 39 EXPERIMENTAL SECTION 41 Sample preparation 41 Instrumentation 42 Contact angle measurements 42 Infrared spectroscopy 42 RESULTS AND DISCUSSION 43 Ellipsometry 43 Contact angle measurements for «-alkanoic acids/Cu 43 IR spectra of multilayers of n-alkanoic acids/Cu General observations and mode assignments Methyl modes Ordering of the polymethylene chain Vibrations of the polymethylene alkyl chain Perfluoro and multicomponent multilayer films 57 CONCLUSIONS 60 REFERENCES V 61 PAPER m. FORMATION, STRUCTURE AND WETTABILITY OF SHORT CHAIN n-ALKANOIC ACIDS ASSEMBLED FROM THE GAS PHASE AT SILVER 63 INTRODUCTION 64 EXPERIMENTAL SECTION 67 Sample preparation 67 Instrumentation 68 Contact angle measurements 68 Infrared spectroscopy 68 RESULTS AND DISCUSSION 69 Contact angle measurements for «-alkanoic acids/Ag 69 IR spectra of n-alkanoic acids/Ag 71 General observations and mode assignments 71 Methyl modes 78 Orientation of the polymethylene chain 80 Vibrations of the polymethylene alkyl chain Discussion of the general utility of the technique n-Alkylthiols at Ag /z-Alkylthiols at Au rt-Alkanoic acids and n-alkylthiols at Cu CONCLUSIONS REFERENCES 91 vi PAPER IV. DEPOSITION OF METAL OVERLAYERS AT END-GROUP FUNCTIONALIZED THIOLATE MONOLAYERS ADSORBED AT AU. SURFACE AND INTERFACIAL CHEMICAL CHARACTERIZATION OF DEPOSITED COPPER OVERLAYERS AT CARBOXYLIC ACID-TERMINATED STRUCTURES 93 XV LIST OF SCHEMES Paper IV Scheme 1. Schematic representation of self-assembled thiolate at Au 95 Scheme 2. Derivatized polymer surface 95 Scheme 3. Dimeric form of hydrogen-bonded carboxylic acids Scheme 4. Polymeric form of hydrogen-bonded carboxylic acids Scheme 5. Proposed structure of hydrogen-bonding in carboxylic-acid terminated monolayers PAPER I SCANNING TUNNELING MICROSCOPY OF EVAPORATED COPPER FILMS AND COMPOSITION AND STRUCTURE OF SPONTANEOUSLY ADSORBED MONOLAYERS OF n-ALKANOIC ACIDS
Inorganica Chimica Acta, 2012
Solution equilibrium studies on the Cu 2+-(A)-(Glu-c-ha) ternary systems ((A) = polyamine: ethylenediamine (en), diethylenetriamine (dien), N,N,N 0 ,N 00 ,N 00-pentamethyldiethylenetriamine (Me 5 dien); (Glu-cha) = L-glutamic-c-hydroxamic acid) have been performed by pH-potentiometry, UV-Vis spectrophotometry and EPR methods. The obtained results suggest the formation of the heteroligand complexes with [Cu(A)(Glu-c-ha)] + stoichiometry in all studied systems. Our spectroscopic results indicate the tetragonal geometry for the [Cu(en)(Glu-c-ha)] + species in which Glu-c-ha acts as a tridentate ligand, the geometry slightly deviated from square pyramidal for [Cu(dien)(Glu-c-ha)] + and strongly deviated from square pyramidal towards trigonal bipyramidal for the [Cu(Me 5 dien)(Glu-c-ha)] + species. In the two latter species Glu-c-ha acts as a bidentate ligand. The coordination modes in these mixed-ligand complexes are discussed.
Hydrogen and Coordination Bonding Supramolecular Structures of Trimesic Acid on Cu(110
Journal of Physical Chemistry A, 2007
The adsorption of trimesic acid (TMA) on Cu(110) has been studied in the temperature range between 130 and 550 K and for coverages up to one monolayer. We combine scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), reflection absorption infrared spectroscopy (RAIRS), X-ray photoemission spectroscopy (XPS), and density functional theory (DFT) calculations to produce a detailed adsorption phase diagram for the TMA/Cu(110) system as a function of the molecular coverage and the substrate temperature. We identify a quite complex set of adsorption phases, which are determined by the interplay between the extent of deprotonation, the intermolecular bonding, and the overall energy minimization. For temperatures up to 280 K, TMA molecules are only partly deprotonated and form hydrogen-bonded structures, which locally exhibit organizational chirality. Above this threshold, the molecules deprotonate completely and form supramolecular metal-organic structures with Cu substrate adatoms. These structures exist in the form of single and double coordination chains, with the molecular coverage driving distinct phase transitions. † Part of the "Giacinto Scoles Festschrift".
The effect of N-methylation of tetra-aza-alkane copper complexes on the axial binding of anions
Inorganica Chimica Acta, 1997
The stability constants of the Cu(II) complex of Me 6 tren (Me 6 trenstris-(2-dimethylaminoethyl)amine) were determined. The axial binding constants of F y , Br y , I y and N to Cu(tren) 2q and Cu(Me 6 tren) 2q (trenstris-(2-aminoethyl)amine) were measured. The results y 3 obtained are compared with those of the axial binding constants of the isomers, i.e. the complexes Cu(trien) 2q and Cu(Me 6 trien) 2q (triens1,4,7,10-tetraazadecane; Me 6 triens2, 5,8,11-tetramethyl-2,5,8,11-tetraazadodecane). The results point out that N-methylation transforms the Cu(II)L complexes into stronger and harder acids. Properties of the copper complexes with TMC (1, and with Me 6 trpn (tris-(3-dimethylaminopropyl)amine) are also reported.
Inorganica Chimica Acta, 2012
Direct reaction of copper(I) chloride with 2-mercaptopyrimidine (pmtH) in the presence of the triphenylphosphine (tpp) in 1:1:2 M ratio forms the mixed ligand Cu(I) complex with formula [CuCl(tpp) 2 (pmtH)] (1). The dimeric {[Cu(tpp)(pmt)] 2 0.5(MeOH)} (2) complex was derived from the reaction of 1 with twofold molar amount of sodium hydroxide. However, the reaction of copper(II) sulfate or nitrate with pmtH and tpp in 1:2:2 M ratio, unexpectedly results in the formation of the [CuSH(tpp) 2 (pmtH)] (3) complex. Further studies have shown that the [Cu(tpp) 2 (pmt)] (4) complex is formed by reacting copper(II) acetate with pmtH in the presence of tpp in 1:2:2 M ratio, while in the absent of tpp, the Cu(CH 3 COO) 2 or CuSO 4 is found to oxidizes pmtH to its corresponding disulfide (pmt) 2. For comparison the mixed ligand silver(I) chloride or nitrate complexes with formula [AgCl(tpp) 2 (pmtH)] (5) or [Ag(NO 3)(tpp) 2 (pmtH)] (6) are also synthesized by reacting of the AgCl or AgNO 3 with pmtH and tpp in 1:2:2 M ratio. The complexes have been characterized by elemental analyses, m.p., vibrational spectroscopy (mid-, far-FT-IR and Raman), 1 H NMR, UV-Vis, ESI-MS, TG-DTA spectroscopic techniques and single crystal X-ray crystallography at ambient conditions. Photolysis of 1-6, was also studied and the results showed formation of triphenylphosphine oxide. The complexes 1-6, were used to study their influence upon the catalytic peroxidation of the linoleic acid by the enzyme lipoxygenase (LOX) experimentally and theoretically. The binding of 1-4 with LOX was also investigated by saturation transfer difference 1 H NMR experiments (STD).
Adsorption structure and bonding of trimesic acid on Cu(100)
Surface Science, 2011
Combining scanning tunneling microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy using synchrotron radiation, we have studied the adsorption and growth of trimesic acid (TMA, 1,3,5-benzenetricarboxylic acid, C 6 H 3 (COOH) 3 ) on Cu(100) in a wide range of coverages (from submonolayer to multilayer ones) at room temperature and after subsequent annealing. A series of coveragedependent TMA structures, transitions between these structures, and their properties are characterized, demonstrating the interplay between the bonding, orientation, and deprotonation reaction of adsorbed species. In particular, it is shown that the degree of deprotonation in TMA overlayers depends on the amount of deposited molecules non-monotonously, and that such behavior is well consistent with the formation mechanism proposed for the TMA/Cu(100) system. The results provide a good platform for further understanding of non-covalent interactions and self-assembly phenomena underlying the growth of supramolecular nanoassemblies of aromatic carboxylic (benzenecarboxylic) acids on metallic substrates.