O mecanismo de nucleac¸˜ao e crescimento de part´ıculas em escala nanom´etrica ´e de grande interesse n˜ao s´o dos que querem explor´a-las tecnologicamente como tamb´em do que desejam investigar o efeito de outras mol´eculas coadjuvantes pre- sente no meio reacional. No caso das nanopart´ıculas de azul da Pr´ussia, o meca- nismo de formac¸˜ao existente na s´ıntese usual via pol´ımero/Fe2+ e [Fe(CN)6]3− deve
ser distinto do que ocorre quando o precursor ´e o metalopol´ımero. No primeiro caso o pol´ımero age adsorvendo-se nos n´ucleos em crescimento e no segundo caso o meta- lopol´ımero, al´em dessa func¸˜ao, age na liberac¸˜ao dos blocos de construc¸˜ao Fe(CN)3−5 que reagir˜ao com Fe3+ adicionado.
Um experimento visando sondar o mecanismo de formac¸˜ao de AP a partir do [Fe(CN)5(P4VP)25]3− foi feito titulando-se uma soluc¸˜ao dilu´ıda do metalopol´ımero
com uma soluc¸˜ao concentrada de FeC`3. Como controle, o mesmo experimento foi
feito com o solvente puro e com a P4VP pura. Espectros UV-Vis foram tomados logo ap´os as adic¸˜oes consecutivas das al´ıquotas de FeC`3, onde se observou formac¸˜ao da
banda MMCT na regi˜ao acima de ∼800 nm somente quando havia Fe(CN)3−5 .
Os espectros eletrˆonicos obtidos constam nas Figuras 5.7a-b. A Figura 5.7c exibe a absorbˆancia no m´aximo da banda e sua posic¸˜ao em cm−1 em func¸˜ao da raz˜ao Fe3+/Fe(CN)3−5 . Observa-se que a intensidade da banda deixa de aumentar quando esta raz˜ao atinge o valor de 1,0-1,2, sugerindo descontinuidade na formac¸˜ao do produto AP quando a estequiometria atinge essa faixa. Simultaneamente, a banda MMCT desloca-se para maiores energias conforme aumenta a quantidade de Fe3+ relativa a de Fe(CN)3−5 , indicando que o acoplamento eletrˆonico entre os ´atomos de
(a)
(b)
(c)
Figura 5.7: Espectros UV-Vis do metalopol´ımero [Fe(CN)5(P4VP)25]3−mediante adic¸˜ao de porc¸˜oes de FeC`3
equivalentes a f = Fe3+/Fe(CN)3−5 de 0 a 1(a) e de 0 a 4 (b). Posic¸˜ao νmaxdo m´aximo da banda obtido por
ajuste por gaussiana no intervalo de 12,5-10×103cm−1(800-1000 nm) e o valor da absorbˆancia em νmax(c).
ferro ´e sens´ıvel `a quantidade relativa dos n´ucleos met´alicos na estrutura do composto. Enfim, a investigac¸˜ao do mecanismo que leva `a formac¸˜ao de AP a partir dos me- talopol´ımeros ´e um campo a ser explorado em futuros trabalhos, podendo resultar em uma sequˆencia de reac¸˜oes que culminam na formac¸˜ao do produto, em estimati- vas da composic¸˜ao ou na revelac¸˜ao da influˆencia da raz˜ao py/Fe, por exemplo. Este trabalho se encerra enfocando a viabilidade da produc¸˜ao de estruturas auto-montadas de pol´ımeros de coordenac¸˜ao, cujos blocos de construc¸˜ao s˜ao fornecidos por macro- mol´eculas h´ıbridas planejadas atrav´es da qu´ımica de coordenac¸˜ao.
A reac¸˜ao entre o pol´ımero hidrof´obico poli(4-vinilpiridina) com o complexo hi- drof´ılico pentacianoferrato de s´odio gerou uma macromol´ecula h´ıbrida orgˆanico- inorgˆanica [Fe(CN)5(P4VP)S]3− com composic¸˜ao S controlada experimentalmente
pela raz˜ao monˆomero/pentacianoferrato colocada para reagir, desde que S seja maior que ∼ 3,5 unidades monom´ericas para cada unidade Fe(CN)3−5 . A principal evidˆencia da s´ıntese esteve na transic¸˜ao de mistura bif´asica para homogˆenea observada visual- mente ap´os a adic¸˜ao de uma soluc¸˜ao aquosa do complexo `a uma soluc¸˜ao etan´olica do pol´ımero, revelando assim que a macromol´ecula contendo porc¸˜oes sol´uveis em ´agua (meros complexados, porc¸˜ao inorgˆanica) e outras em etanol (meros 4-vinilpiridina livres, porc¸˜ao orgˆanica) torna-se sol´uvel em misturas ´agua/etanol numa ampla faixa de composic¸˜ao.
Em virtude da compatibilizac¸˜ao de porc¸˜oes de solubilidade distintas numa mesma mol´ecula, as propriedades de cada porc¸˜ao foram alteradas pela quantidade rela- tiva da outra porc¸˜ao. Os resultados dos estudos de solvatocromismo mostram que quanto maior ´e a extens˜ao das porc¸˜oes de cadeia de monˆomeros livres, maior ´e a solvatac¸˜ao do pentacianoferrato por etanol. Em outras palavras, a polaridade do am- biente qu´ımico do complexo ´e modulada pelo pol´ımero.
Amostras contendo grande quantidade de complexo como a [Fe(CN)5(P4VP)5]3−
´agua quando o meio encontra-se pobre em ´agua (XH2O< 0,42 e 0,25 respectivamente,
Figura 4.7). Essa observac¸˜ao foi racionalizada idealizando-se a formac¸˜ao de regi˜oes ricas em complexo e em de ´agua, formando “bols˜oes” hidrof´ılicos. Uma alterac¸˜ao no modelo de solvatac¸˜ao preferencial82 foi proposta, tornando-o capaz de prever a XH2O em que ocorre a invers˜ao pela inserc¸˜ao do parˆametro xH2O(B). Amostras
contendo pequena quantidade de complexo, por outro lado, tem os grupos Fe(CN)3−5 completamente solvatados por etanol em XH2O = 0,42. Abaixo desse valor, os meros
4vpy passam a solvatar preferencialmente o complexo. De um modo geral, dado um par de solventes, a solvatac¸˜ao ´e preferencial pelo menos polar.
A influˆencia do pentacianoferrato nas propriedades do pol´ımero est´a na alterac¸˜ao de sua viscosidade intr´ınseca, que se relaciona com a conformac¸˜ao da macromol´ecula em soluc¸˜ao. Foi observada a tendˆencia de que quanto maior a quantidade do com- plexo coordenado `a cadeia polim´erica, maior sua viscosidade intr´ınseca e consequen- temente, maior ´e o volume do novelo polim´erico em soluc¸˜ao, em virtude majoritaria- mente da repuls˜ao eletrost´atica entre os grupos Fe(CN)3−5 . O volume dos novelos da amostra [Fe(CN)5(P4VP)10]3− chegam a ser 7 vezes maiores que o da P4VP pura.
Em decorrˆencia dessa observac¸˜ao, pode-se afirmar que a densidade de carga na cadeia modula o qu˜ao “aberto” ou “fechado” o novelo polim´erico se encontra, ou seja, modula a acessibilidade de mol´eculas pequenas ao interior do novelo. Este fato, aliado `a modulac¸˜ao da polaridade do ambiente qu´ımico do centro met´alico, pode ter importantes implicac¸˜oes em futuros estudos sobre cat´alise de reac¸˜oes no microambiente polim´erico ou mimese de metaloenzimas, por exemplo.
Variando-se a composic¸˜ao do solvente da amostra [Fe(CN)5(P4VP)25]3−, notou-
Um m´aximo em [η] ´e observado em valores de XH2O intermedi´arios, denotando a
condic¸˜ao de melhor solvatac¸˜ao dos meros complexados e dos meros da cadeia de P4VP original. Apesar da mudanc¸a da conformac¸˜ao da cadeia polim´erica, solvatac¸˜ao preferencial por etanol foi observada em toda a faixa de composic¸˜ao, sem a presenc¸a de um m´aximo. Isto indica que a conformac¸˜ao da cadeia provavelmente n˜ao tem correlac¸˜ao com a polaridade da esfera de solvatac¸˜ao das unidades Fe(CN)3−5 .
Os metalopol´ımeros mostraram-se aplic´aveis na produc¸˜ao de estruturas tipo azul da Pr´ussia, resultando em part´ıculas com elevada estabilidade coloidal e tendˆencia de o tamanho m´edio ser inversamente proporcional `a raz˜ao py/Fe do metalopol´ımero precursor. A energia e a absortividade molar das transic¸˜oes MMCT dependeram da raz˜ao py/Fe, logo, a composic¸˜ao controlada experimentalmente interfere no grau de interac¸˜ao eletrˆonica dos centros FeII e FeIII deste composto de valˆencia mista. Foi proposto um modelo para racionalizar a interac¸˜ao das part´ıculas de AP com mol´eculas adsorvidas com base na alterac¸˜ao da energia da banda MMCT observada. Por fim, a investigac¸˜ao do mecanismo de formac¸˜ao dessas estruturas permitiu estimar uma composic¸˜ao para a amostra Fe[Fe(CN)5(P4VP)25] , que se encontra concordante
[1] H.J. Buser, D. Schwarzenbach, W. Petter, and A. Ludi. The crystal structure of prussian blue: Fe4[Fe(CN)6]3·xH2O. Inorganic Chemistry, 16(11):2704–
2710, 1977.
[2] I. Manners. Synthetic Metal-Containing Polymers. Wiley-VCH, Weinheim, 2004.
[3] I. Manners. Putting metals into polymers. Science, 294(5547):1664–1666, 2001.
[4] G.R. Whittell and I. Manners. Metallopolymers: New multifunctional materi- als. Advanced Materials, 19(21):3439–3468, 2007.
[5] F.S. Arimoto and A.C. Haven Jr. Derivatives of dicyclopentadienyliron. Journal of the American Chemical Society, 77(23):6295–6297, 1955.
[6] John E. Sheats, Charles R. Carraher Jr., and Charles U. Pittman Jr., editors. Metal-Containing Polymeric Systems. Plenum Press, New York, 1985.
[7] I. Manners. Polymer science with transition metals and main group elements: Towards functional, supramolecular inorganic polymeric materials. Journal of Polymer Science, Part A: Polymer Chemistry, 40(2):179–191, 2002.
[8] L. Dennany, C.F. Hogan, T.E. Keyes, and R.J. Forster. Effect of surface immo- bilization on the electrochemiluminescence of ruthenium-containing metallo- polymers. Analytical Chemistry, 78(5):1412–1417, 2006.
[9] A. Devadoss, C. Dickinson, T.E. Keyes, and R.J. Forster. Electrochemilumi- nescent metallopolymer-nanoparticle composites: Nanoparticle size effects. Analytical Chemistry, 83(6):2383–2387, 2011.
[10] X. Wang and R. McHale. Metal-containing polymers: Building blocks for functional (nano)materials. Macromolecular Rapid Communications, 31(4):331, 2010.
[11] F. S. Han, M. Higuchi, and D. G. Kurth. Metallosupramolecular polyelec- trolytes self-assembled from various pyridine ring-substituted bisterpyridines and metal ions: Photophysical, electrochemical, and electrochromic proper- ties. Journal of the American Chemical Society, 130(6):2073–2081, 2008. [12] H. Maeda, M. Hasegawa, T. Hashimoto, T.b Kakimoto, S. Nishio, and T. Na-
kanishi. Nanoscale spherical architectures fabricated by metal coordination of multiple dipyrrin moieties. Journal of the American Chemical Society, 128(31):10024–10025, 2006.
[13] P.G. Lacroix, W. Lin, and G.K. Wong. Poly(vinylpyridine) and related poly- mers as guests for organotransition-metal-based nlo chromophores. Chemistry of Materials, 7(7):1293–1298, 1995.
[14] C.V. Franco, M. Marques da Silva Paula, G. Goulart, L.F.C.P. de Lima, L.K. Noda, and N.S. Gonc¸alves. Thermal analysis, raman spectroscopy and scanning electron microscopy of new polymeric material containing in-chain ruthenium complex: Poly-trans-[RuCl2(vpy)4]-co-styrene and poly-trans-
[RuCl2(vpy)4]-4 vinylpyridine-styrene. Materials Letters, 60(21-22):2549–
2553, 2006.
[15] H.E. Toma, J.M. Malin, and E. Giesbrecht. The ion pentacyano(dimethyl sul- foxide)ferrate(II). synthesis, characterization and substitution kinetics in aque- ous solution. Inorganic Chemistry, 12(9):2084–2089, 1973.
[16] H.E. Toma and J.M. Malin. Kinetics of formation and stability constants of some pentacyanoferrate(II) complexes of aromatic nitrogen heterocycles. Inorganic Chemistry, 12(9):2080–2083, 1973.
[17] D.J. Kenney, T.P. Flynn, and J.B. Gallini. Reactions of ferropentacyanamines. Journal of Inorganic and Nuclear Chemistry, 20(1-2):75–81, 1961.
[18] H.E. Toma and J.M. Malin. Properties and reactivity of some pentacyanofer- rate(II) complexes of aromatic nitrogen heterocycles. Inorganic Chemistry, 12(5):1039–1045, 1973.
[19] H.E. Toma and J.M. Malin. Dissociation kinetics of pentacyanoiron(II) com- plexes of ammonia and methylamine. Inorganic Chemistry, 13(7):1772–1774, 1974.
[20] A.R. Butler and C. Glidewell. Recent chemical studies of sodium nitroprus- side relevant to its hypotensive action. Chemical Society Reviews, 16:361– 380, 1987.
[21] S.M. Shishido and M.G. de Oliveira. Photosensitivity of aqueous sodium ni- troprusside solutions: Nitric oxide release versus cyanide toxicity. Progress in Reaction Kinetics and Mechanism, 26(2-3):239–261, 2001.
[22] L.M. Baraldo, P. Forlano, A.R. Parise, L.D. Slep, and J.A. Olabe. Advan- ces in the coordination chemistry of [M(CN)5l]n− ions (M = Fe, Ru, Os).
Coordination Chemistry Reviews, 219-221:881–921, 2001.
[23] I.A. Funai, M.A. Blesa, and J.A. Olabe. Hydrazine autoxidation in solution: catalysis by pentacyanoferrate(II). Polyhedron, 8(4):419–426, 1989.
[24] K. Ogura and M. Kaneko. Reduction of co to methanol by Everitt’s salt using pentacyanoferrate(II) or pentachlorochromate(III) and methanol as homoge- neous catalysts. Journal of Molecular Catalysis, 31(1):49–56, 1985.
[25] K. Ogura and M. Takagi. Electrocatalytic reduction of carbon dioxide to methanol. part iv. assessment of the current-potential curves leading to reduc- tion. Journal of electroanalytical chemistry and interfacial electrochemistry, 204(1-2):209–216, 1986.
[26] K. Ogura, C.T. Migita, and T. Nagaoka. Electrochemical reduction of carbon dioxide with an electrode mediator and homogeneous catalysts. Journal of Molecular Catalysis, 56(1 -3 pt 2):276–283, 1989.
[27] J.P. Sauvage and C. (Eds.) Dietrich-Buchecker. Molecular Catenanes, Rotaxanes and Knots. Wiley-VCH, Weinheim, 1999.
[28] A.J. Baer and D.H. Macartney. α- and β-cyclodextrin rotaxanes of µ- bis(4-pyridyl)bis[pentacyanoferrate(II)] complexes. Inorganic Chemistry, 39(7):1410–1417, 2000.
[29] H.E. Toma, R.M. Serrasqueiro, R.C. Rocha, G.J.F. Demets, H. Winnis- chofer, K. Araki, P.E.A. Ribeiro, and C.L.b Donnici. Photophysical and photoelectrochemical properties of the bis(2,2’-bipyridine)(4,4’-dimethylthio- 2,2’-bipyridine) ruthenium(II) complex. Journal of Photochemistry and Photobiology A: Chemistry, 135(2-3):185–191, 2000.
[30] H.E. Toma and A.B.P. Lever. Spectroscopic and kinetic studies on a series of di- to heptanuclear tris(bipyrazine)ruthenium(II)-pentacyanoferrate(II) com- plexes in aqueous solution. Inorganic Chemistry, 25(2):176–181, 1986.
[31] C. Hidalgo-Luangdilok and A.B. Bocarsly. Nickel-electrode-confined Ru(bipyrazine)3[Fe(CN)5]n2−3n: An inorganic structural matrix yielding pho-
toinduced multinuclear charge-transfer reactivity. Inorganic Chemistry, 29(16):2894–2900, 1990.
[32] H. Winnischofer, F.M. Engelmann, H.E. Toma, K. Araki, and H.R. Rechen- berg. Acid-base and spectroscopic properties of a novel supramolecular porphyrin bonded to four pentacyanoferrate(II) groups. Inorganica Chimica Acta, 338:27–35, 2002.
[33] G. Liang, J. Xu, and X. Wang. Synthesis and characterization of organometal- lic coordination polymer nanoshells of Prussian blue using miniemulsion pe- riphery polymerization (MEPP). Journal of the American Chemical Society, 131(15):5378–5379, 2009.
[34] J.T. Culp, J.-H. Park, F. Frye, Y.-D. Huh, M.W. Meisel, and D.R. Talham. Magnetism of metal cyanide networks assembled at interfaces. Coordination Chemistry Reviews, 249(23):2642–2648, 2005.
[35] J.T. Culp, J.-H. Park, D. Stratakis, M.W. Meisel, and D.R. Talham. Supra- molecular assembly at interfaces: Formation of an extended two-dimensional coordinate covalent square grid network at the air-water interface. Journal of the American Chemical Society, 124(34):10083–10090, 2002.
[36] J.T. Culp, J.-H. Park, I.O. Benitez, M.W. Meisel, and D.R.a Talham. Two applications of metal cyanide square grid monolayers: Studies of evolving magnetic properties in layered films and templating prussian blue family thin films. Polyhedron, 22(14-17):2125–2131, 2003.
[37] J.T. Culp, J.-H. Park, M.W. Meisel, and D.R. Talham. Interface direc- ted assembly of cyanide-bridged Fe-Co and Fe-Mn square grid networks. Polyhedron, 22(22):3059–3064, 2003.
[38] R. McHale, N. Ghasdian, Y. Liu, M.B. Ward, N.S. Hondow, H. Wang, Y. Miao, R. Brydson, and X. Wang. Prussian blue coordination polymer nanobox synthesis using miniemulsion periphery polymerization (MEPP). Chemical Communications, 46(25):4574–4576, 2010.
[39] K. Shigehara, N. Oyama, and F.C. Anson. Electrochemical responses of elec- trodes coated with redox polymers. evidence for control of charge-transfer ra- tes across polymeric layers by electron exchange between incorporated redox sites. Journal of the American Chemical Society, 103(10):2552–2558, 1981. [40] N. Oyama and F.C. Anson. Facile attachment of transition metal complexes
to graphite electrodes coated with polymeric ligands. observation and control of metal-ligand coordination among reactants confined to electrode surfaces. Journal of the American Chemical Society, 101(3):739–741, 1979.
[41] N. Oyama and F.C. Anson. Polymeric ligands as anchoring groups for the attachment of metal complexes to graphite electrode surfaces. Journal of the American Chemical Society, 101(13):3450–3456, 1979.
[42] N. Oyama, T. Ohsaka, M. Kaneko, K. Sato, and H. Matsuda. Electrode kinetics of the Fe(CN)4−/3−6 and Fe(CN)3−/2−5 complexes confined to poly- mer film on graphite surfaces. Journal of the American Chemical Society, 105(19):6003–6008, 1983.
[43] H.-R. Zumbrunnen and F.C. Anson. Electrostatic binding of anions and cati- ons to graphite electrodes coated with a polyelectrolyte containing both posi- tive and negative fixed charges. Journal of Electroanalytical Chemistry, 152(1- 2):111–124, 1983.
[44] N. Oyama, T. Shimomura, and F.C. Shigehara, K.and Anson. Electrochemical responses of multiply-charged transition metal complexes bound electrostati- cally to graphite electrode surfaces coated with polyelectrolytes. Journal of Electroanalytical Chemistry, 112(2):271–280, 1980.
[45] N. Oyama, H. Yamamoto, T. Ohsaka, and M. Kaneko. Photoelectrochemical behavior of the Fe(CN)2−5 complexes coordinated to the poly(4-vinylpyridine)
film on graphite surfaces. Bulletin of the Chemical Society of Japan, 57(10):2942–2946, 1984.
[46] M. Sharp and H. Larsson. Studies of the temperature dependence of charge propagation rates in quaternized poly(4-vinylpyridine) polymers con- taining electrostatically bound and coordinated redox sites. Journal of Electroanalytical Chemistry, 386(1-2):189–195, 1995.
[47] H. Larsson, B. Lindholm, and M. Sharp. Electron transport in quaternized poly(4-vinylpyridine) films containing pentacyanoferrate(ii/iii) on electrodes. the influence of the binding type of the electroactive complex. Journal of Electroanalytical Chemistry, 336(1-2):263–279, 1992.
[48] J. Woodward. Praeparatio Caerulei Prussiaci ex Germania missa ad Johannem Woodward, M. D. Prof. Med. Gresh. R. S. S. Philosophical Transactions of the Royal Society of London, XXXIII, 1724-1725.
[49] Anˆonimo. Miscellanea berolinensia ad incrementum scientiarum. sump- tibus J.C. Papenii, 1710. dispon´ıvel em http://booklens.com/miscellanea- berolinensia-ad-incrementum-scientiarum pela Deutsche Akademie der Wis- senschaften zu Berlin.
[50] E. Dujardin and S. Mann. Morphosynthesis of molecular magnetic materials. Advanced Materials, 16(13):1125–1129, 2004.
[51] M. Verdaguer, A. Bleuzen, V. Marvaud, J. Vaissermann, M. Seuleiman, C. Desplanches, A. Scuiller, C. Train, R. Garde, G. Gelly, C. Lomenech, P. Rosenman, I.and Veillet, C. Cartier, and F. Villain. Molecules to build so- lids: High Tc molecule-based magnets by design and recent revival of cyano
complexes chemistry. Coordination Chemistry Reviews, 190-192:1023–1047, 1999.
[52] O. Kahn. Molecular magnets: Blueprint for success. Nature, 378(6558):667– 668, 1995.
[53] O. Sato, T. Iyoda, A. Fujishima, and K. Hashimoto. Photoinduced magnetiza- tion of a cobalt-iron cyanide. Science, 272(5262):704–705, 1996.
[54] Z.-Z. Gu, Y. Einaga, O. Sato, A. Fujishima, and K. Hashimoto. Photo- and dehydration-induced charge transfer processes accompanied with spin transi- tion on CoFe(CN)5NH3·6H2O. Journal of Solid State Chemistry, 159(2):336–
342, 2001.
[55] S. Ferlay, T. Mallah, R. Ouah`es, P. Veillet, and M. Verdaguer. A room-temperature organometallic magnet based on prussian blue. Nature, 378(6558):701–703, 1995.
[56] S. Vaucher, M. Li, and S. Mann. Synthesis of prussian blue nanoparticles and nanocrystal superlattices in reverse microemulsions. Angewandte Chemie - International Edition, 39(10):1793–1796, 2000.
[57] J. Vaucher, S.and Fielden, M. Li, E. Dujardin, and S. Mann. Molecule-based magnetic nanoparticles: Synthesis of cobalt hexacyanoferrate, cobalt pen- tacyanonitrosylferrate, and chromium hexacyanochromate coordination poly- mers in water-in-oil microemulsions. Nano Letters, 2(3):225–229, 2002. [58] B.M. Chadwick and A.G. Sharpe. Transition metal cyanides and their com-
plexes. Advances in Inorganic Chemistry and Radiochemistry, 8(C):83–176, 1966.
[59] Q. Kong, X. Chen, J. Yao, and D.b Xue. Preparation of poly(n-vinyl-2- pyrrolidone)-stabilized transition metal (Fe, Co, Ni and Cu) hexacyanoferrate nanoparticles. Nanotechnology, 16(1):164–168, 2005.
[60] X. Shen, S. Wu, Y. Liu, K. Wang, Z. Xu, and W.a Liu. Morphology syntheses and properties of well-defined Prussian blue nanocrystals by a facile solution approach. Journal of Colloid and Interface Science, 329(1):188–195, 2009. [61] V. Hornok and I. D´ek´any. Synthesis and stabilization of Prussian blue nano-
particles and application for sensors. Journal of Colloid and Interface Science, 309(1):176–182, 2007.
[62] T. Uemura, M. Ohba, and S. Kitagawa. Size and surface effects of prus- sian blue nanoparticles protected by organic polymers. Inorganic Chemistry, 43(23):7339–7345, 2004.
[63] R. J. Hunter. Introduction to modern colloid science. Oxford University Press, 1993.
[64] F. Ricci and G. Palleschi. Sensor and biosensor preparation, optimisa- tion and applications of prussian blue modified electrodes. Biosensors and Bioelectronics, 21(3):389–407, 2005.
[65] G. Brauer. Handbook of preparative inorganic chemistry, volume 1. Academic Press, New York, 2nd edition, 1963.
[66] K. A. Hofmann. ¨Uber Eisenpentacyanverbindungen. Justus Liebig’s Annalen der Chemie, 312:1–32, 1900.
[67] H.E. Toma. Iron(II) catalysis in the oxidation of the aquopentacyanoferrate(II) complex by molecular oxygen. Inorganica Chimica Acta, 15(C):205–211, 1975.
[68] D. L. Macartney. Properties and reactions of substituted pentacyanoferrate(II) complexes. Reviews in Inorganic Chemistry, 9(2-3):101–151, 1988.
[69] J.A. Olabe and H.O. Zerga. Thermal decomposition of the pentacyanoaquo- ferrate(II) ion in aqueous solution. Inorganic Chemistry, 22(26):4156–4158, 1983.
[70] G. Emschwiller. Sur le complexe binucleaire issu des aquopentacyanoferrates. Comptes Rendus Hebdomadaires des Seances de L’Academie des Sciences Serie C, 265(5):281–&, 1967.
[71] G. Emschwiller and C. K. Jørgensen. Electron transfer bands of binuclear iron (II, III) complexes containing two cyanide bridges. Chemical Physics Letters, 5(9):561–563, 1970.
[72] G. Emschwiller. Binuclear cyano complexes of iron. Comptes
Rendus Hebdomadaires des Seances de L’Academie des Sciences Serie C, 268(8):692–&, 1969.
[73] H. E. Toma. Influˆencias das interac¸˜oes de transferˆencia de el´etrons no comportamento dos complexos de pentaaminrutˆenio(II) e petacianoferrato(II) com ligantes insaturados. PhD thesis, Instituto de Qu´ımica da Universidade de S˜ao Paulo, S˜ao Paulo, 1974.
[74] H.E. Toma and M.S. Takasugi. Spectroscopic studies of preferential and asym- metric solvation in substituted cyanoiron(II) complexes. Journal of Solution Chemistry, 12(8):547–561, 1983.
[75] M.J. Blandamer, J. Burgess, and R.I. Haines. Kinetic and equilibrium pro- perties of pentacyano(3,5-dimethylpyridine)-iron(II) and related anions in mi- xed aqueous solvents. Journal of the Chemical Society, Dalton Transactions, (14):1293–1298, 1976.
[76] N.V. Hrepic and J.M. Malin. Electron transfer and ligand substitution reacti- ons of the ion pentacyano(4-aminopyridine)ferrate(II). Inorganic Chemistry, 18(2):409–413, 1979.
[77] X. Zhou, S.H. Goh, S.Y. Lee, and K.L. Tan. Interpolymer complexa- tion between poly(vinylphosphonic acid) and poly(vinylpyridine)s. Polymer, 38(21):5333–5338, 1997.
[78] S. Valkama, J. Hartikainen, M. Torkkeli, R. Serimaa, J. Ruokolainen, K. Ris- sanen, G. Ten Brinke, and O. Ikkala. Self-organized nanostructures of poly(4-vinylpyridine), polyaniline and polyamides due to metal complexation. Macromolecular Symposia, 186:87–92, 2002.
[79] K. Sheng and B. Yan. A new luminescent molecular based terbium hybrid ma- terial containing both organic polymeric chains and inorganic silica networks. Journal of Materials Science: Materials in Electronics, 21(1):65–71, 2010. [80] S.-W. Kuo, P.-H. Tung, and F.-C. Chang. Syntheses and the study of stron-
gly hydrogen-bonded poly(vinylphenol-b- vinylpyridine) diblock copolymer through anionic polymerization. Macromolecules, 39(26):9388–9395, 2006. [81] M. Szafran, J. Koput, Z. Dega-Szafran, and M. Pankowski. Ab initio and DFT
calculations of the structure and vibrational spectra of trigonelline. Journal of Molecular Structure, 614(1-3):97–108, 2002.
[82] L.S. Frankel, C.H. Langford, and T.R. Stengle. Nuclear magnetic resonance techniques for the study of preferential solvation and the thermodynamics of preferential solvation. Journal of Physical Chemistry, 74(6):1376–1381, 1970. [83] M. Chanda. Introduction to Polymer Science and Chemistry. A Problem
Solving Approach. CRC Press, Boca Ranton, FL, 2006.
[84] M.L. Huggins. The viscosity of dilute solutions of long-chain molecules. IV. Dependence on concentration. Journal of the American Chemical Society, 64(11):2716–2718, 1942.
[85] H. Morawetz. Macromolecules in solution. John Wiley & Sons, 2nd edition, 1975.
[86] F. Booth. The electroviscous effect for suspensions of solid spherical particles. Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences, 203(1075):533–551, 1950.
[87] L. Jiang, D. Yang, and S.B. Chen. Electroviscous effects of dilute so- dium poly(styrenesulfonate) solutions in simple shear flow. Macromolecules, 34(11):3730–3735, 2001.
[88] L. Jiang and S.B. Chen. Electroviscous effect on the rheology of a dilute solu- tion of flexible polyelectrolytes in extensional flow. Journal of Non-Newtonian Fluid Mechanics, 96(3):445–458, 2001.
[89] R.M. Fuoss. Viscosity function for polyelectrolytes. Journal of Polymer Science, 3(4):603–604, 1948.
[90] R.M. Fuoss and U.P. Strauss. Electrostatic interaction of polyelectrolytes and simple electrolytes. Journal of Polymer Science, 3(4):602–603, 1948.
[91] R.M. Fuoss. Polyelectrolytes. Science, 108(2812):545–550, 1948.
[92] S. Dragan and L. Ghimici. Viscometric behaviour of some hydrophobically modified cationic polyelectrolytes. Polymer, 42(7):2887–2891, 2001.
[93] S.-H. Yoo, M.L. Fishman, A.T. Hotchkiss Jr., and G.L. Hyeon. Visco- metric behavior of high-methoxy and low-methoxy pectin solutions. Food Hydrocolloids, 20(1):62–67, 2006.
[94] A. Mansri, L. Tennouga, and J. Desbri`eres. Neutralization degree effect on viscosimetric behaviour of hydrolyzed polyacrylamide-poly(4-vinylpyridine) [AD37-P4VP] mixture in aqueous solution. Polymer Bulletin, 61(6):771–777, 2008.
[95] J. Yamanaka, H. Araie, H. Matsuoka, H. Kitano, N. Ise, T. Yamaguchi, S. Sa- eki, and M. Tsubokawa. Revisit to the intrinsic viscosity-molecular weight relationship of ionic polymers. 4. Viscosity behavior of ethylene glycol/water solutions of sodium poly(styrenesulfonate). Macromolecules, 24(11):3206– 3208, 1991.
[96] J. Yamanaka, H. Araie, H. Matsuoka, H. Kitano, N. Ise, T. Yamaguchi, S. Sa- eki, and M. Tsubokawa. Revisit to the intrinsic viscosity-molecular weight relationship of ionic polymers. 5. further studies on solution viscosity of so- dium poly(styrenesulfonates). Macromolecules, 24(23):6156–6159, 1991. [97] H. Vink. Rheology of dilute polyelectrolyte solutions. Polymer, 33(17):3711–
3716, 1992.
[98] J.L.M.S. Ganter, M. Milas, and M. Rinaudo. On the viscosity of sodium