Research within this project resulted in 37 joint publications in international journals and 21 congress contributions with published abstracts. Researchers from participating institutions made 44 exchange missions (4 STSM) of total duration 110 weeks. One WGM was organized. Joint research included also participants from D14 (Functional molecular materials) and D20 (Metal compounds in medicine) actions. Research topics are grouped in publications dealing with redox chemistry of host-guest complexes, self-organized monolayers, redox labels inside protein structures and new coordination compounds for catalysis and other applications. The last two topics represent the cooperation with other COST actions.

Electron transfer of molecules included in host cavity of cyclodextrins
Host-guest complexes of cyclodextrins have a significant scope of applications. Almost negligible interest was paid to possible changes of redox properties upon inclusion of an electroactive compound in cavities. Interactions inside a molecular cavity and a confined reaction space can eliminate certain bond-breaking reactions and enable less favorable processes. Research within the network dealt mainly with decomposition reactions of pesticides and to a lesser extent with a carbonylation reaction of organometallic iron complex. Participants of the network shared tasks of preparing and characterizing of inclusion complexes. In all studies the mechanism of free compounds was scrutinized and difference of reaction pathways in complexed form were identified. Three dicarboxiimide-type pesticides, vinclozolin, iprodion and procymidon have rather similar redox properties yielding a variety of final reduction products. Elimination of heterocycles yielding aniline are the main reaction pathways, however, the cleavage of C-Cl bond due to an internal charge transfer was confirmed [1,2]. The formation of a host-guest complex profoundly changes the reductive decomposition of these pesticides. Protecting effect of the molecular cavity is clearly seen [3,4]. Vinclozolin, 3-(3,5-dichlorofenyl)-5-methyl-5-vinyl-1,3-oxazolidine-2,4-dion, forms an inclusion complex only with cyclodextrin. It can be prepared in solid form and the formation in aqueous medium can be monitored by spectroscopy. Other oligosacharides do not form solid- state complexes. Nevertheless all three cyclodextrins influence the redox mechanism. This proved their interaction with the decomposition intermediates and final products. The reduction of free vinclozoline results predominantly in a mixture of chloroaniline products. The presence of cyclodextrin moiety protects the heterocyclic part of the pesticide. The main decomposition reaction in this case is the cleavage of C Cl bond, while the heterocyclic C-N bond is protected in the cavity. The imidazoline cycle is preserved during the reduction process [5]. The final product distribution obtained by electrolysis in absence and in presence of cyclodextrin is considerably changed. Molecular modeling using semi-empirical AM1 quantum chemical method complemented experimental observations. Modeling confirmed the importance of interaction of active molecule with OH groups of the host molecule [6]. Nitropesticides derived from diphenyl ether exert similar effects. The cyclodextrin cavity influences substantially the nitro radical stability toward the second reduction step. Redox activation of organometallic complexes inside a nano-cavity of an inert host molecule leads to a remarkable suppression of undesirable side reactions. This principle was applied to a carbonylation reaction, an important process for performing the prolongation of an alkyl chain. Alkyl carbonyls of iron undergo this reaction by inserting a coordinated CO ligand in Fe-alkyl bond. Thermal activation is possible, however requires high temperature and pressure and long reaction time. The redox activation initiates carbonylation at ambient conditions. The catalytic cycle is terminated by several side reactions. We succeeded to prepare an inclusion complex of dicarbonyl (cyclopentadienyl) methyl iron and cyclodextrin. The redox activity of the iron complex is maintained, however the side reactions are largely eliminated. Free CO released and reinserted during the process is evidently kept inside the molecular cavity, which prevents its diffusion away from reaction partners [7].

Self-organized monolayers
The formation of self-organized monolayers at surfaces is one of the topics of electrochemistry. We applied predominantly the impedance methods to investigation of two such cases. Triazine pesticides are in the focus of interest because of their environmental risks. Very minor structural difference in atrazine and terbutylazine causes profoundly large contamination problems. Atrazine was banned years ago, however, the ground water contamination persists. Terbutylazine is an acceptable herbicide. The structural difference amounts just one methyl group (isopropyl and t-butyl substituent on an amino group). We proved that this small structural difference causes a considerable effect on the value of the critical phase transition temperature (the Kraft point) for the formation of condensed molecular film [8]. Work shows that the Kraft point can be a convenient parameter for estimation of contamination risks of newly introduced pesticides. The investigation of monolayers involved also Monte Carlo simulation of growth of linear structures competing with a chaotic growth for surfactants where several non-equivalent interacting centers are present . Spontaneous surface self-organization was investigated for 1,3,5-tris[10-(3-ethylthiopropyl)dimethylsilyl-1,10-dicarba-closo-decaboran-1-yl]benzene, which was prepared by partner laboratories with the aim to produce new materials of low dimensionality. Conditions for the formation of stable grids interconnected by metal atoms were found [10]. This feature is supposed to be used for a design of more complex molecular grids with a repetitive functional motive. The grid structure was interpreted on basis of estimation of molecular footprints in the adsorbed state by combination of Langmuir-Blodgett isotherms and charge consumed for generation of interconnecting metal cations binding molecules by -S-Hg-S- bonds. The grid model was verified by AM1 methods [9].

Artificial redox active centers of proteins (redox labeling)
A redox active organometallic fragment can label proteins by a covalent bond to lysine. Labeled proteins are suitable for analytical purpose (especially in the clinical praxis) and immunoassay methods could be worked out. The collaborating partner was a COST D20 participant. The complex tricarbonyl (cyclopentadienyl) manganese yield rather complicated redox mechanism when reduced in its free form. Its binding to bovine serum albumin provides a protecting hydrophobic nano-environment resulting in an uncomplicated fast and reversible single-electron process. Electrochemical signal is suitable for analytical applications. The electrochemical detection proved to be 200 times more sensitive compared to spectral methods [11].

Electron transfer in coordination compounds.
The mechanism of long-distance electron transfer is sought with aim to better understand the efficiency of biological electron transfer transmission and redox processes in supramolecular assemblies. Partner laboratories prepared a series of new compounds permitting to model the communication between multiple redox centers. Conjugated bridging acceptor ligand, 2,5-bis(1-fenyliminoethyl) pyrazine, with two chelate centers unexpectedly stabilizes mixed valence stated during the course of reduction of binuclear complexes [12]. This property is significant for a design of new supramolecular compounds. The effect is due to localization of a molecular orbital responsible for communication between both redox centers at peripheral imino- groups of the ligand. Another work dealt with electron transfer to a coordinated nitrosyl ligand [13]. The redox system NO+/NO" bound to a metallic center, plays a role in electron transfer to metaloenzymes containing low-spin iron atom.
Other model systems involved compounds analogous to natural oxidoreductase. Intraprotein electron transfer in oxido-reductase of flavoenzyme-type assumes a bond flavien-metal, which was never firmly proved. We showed that the redox orbital of dimethylalloxazinu 1 in cooper and tungsten complexes enables two alternative electron- transfer leading to a process localized on ligand or on a metallic center [14]. Our work confirmed similarity of alloxazine and isoalloxazine (riboflavin) in electron transfer processes over the distance <30 A. Model reversible redox system Cu(I)/Cu(II), which is a part of the "type 1 blue copper" proteins is characterized by a very fast electron transfer due to forced geometry around the cooper atom [15]. The evokes a structural compromise between Cu(I) and Cu(II). As a model system we used complex type CuL2 where a bidentate N,S-donor ligand L was 1-methyl-2-(methylthiomethyl)-1H-benzimidazol, 2. The bond angle N-Cu-N remains invariant during the one-electron reduction step, whereas the change of angle S-Cu-S from 145 to 109 deg. markedly reflects the redox state of cooper atom . This complex mimics well the biological redox systems. The heterogeneous electron transfer to three- and four-nuclear organometallic platinum metal clusters evokes often structural changes. One-electron transfer to cycloheptatriene carbonyl complex [Co4(CO)3(µ3-C7H7)(?5-C7H9)] yields a radical with changed hapticity. Following dimerization creates aC-C bond. Dimer surprisingly behaves as a molecule with two independent non-communicating centers. The oxidation almost quantitatively restores the original monomeric form. This principle could be used for a design of a "molecular battery" in which the energy would be stored in the C-C bond [16,17].
The electron-deficient tri-osmium clusters with a benzoheterocyclic ligand 3 are highly reactive coordinatively unsaturated compounds. Our extensive study [18]of 12 compounds employed the following ligands: quinoline, 5-amino-quinoline, 6-methoxo-quinolin, phenanthridine, 5,6-benzoquinoline, quinoxaline, 2-methyl-benzimidazole, 2-methyl-benzotriazole, 2-methyl-benzothiazole, 2-methyl-benzoxazole. Redox properties, spectral characteristics and molecular parameters indicate that the redox potentials correlate well with n›?* electronic transition.
Tetracyano-p-quino-dimethane (TCNQ) and related tetracyanoethene (TCNE) are important ligands for a design of new conducting and magnetic materials. These pi-acceptor ligands can coordinate in neutral, radical anion or dianion forms. The coordination can employ both - and bonds. -bonding enables to form a bridging ligand in a four-nuclear complex. Such a new four-nuclear complex of Re lowers significantly the energetic barrier for electron transfer to TCNQ ligand [19]. Complexes {( 4-TCNX)[Cu(Me3TACN)]4}(BF4)4 (TCNX = TCNE (tetrakyanoethen), TCNQ (7,7,8,8-tetrakyano-p-quinodimethan), TCNB (1,2,4,5-tetracyanobenzen; Me3TACN = 1,4,7-trimethyl-1,4,7-triazacyklononan) were prepared by a reaction of TCNX ligands with [(CH3CN)Cu (Me3TACN)]}(BF4). Nitrile vibration frequences observed in IR region indicate a negligible transfer to TCNX. This way differs Cu complexes [20]from analogous compounds with metals in d6 configuration (MnI, RuII, OsII). Futhermeore, we performed a complete characterization of [( 4-TCNQ){fac-Re(CO)3(bpy)}4]4+. The coordination of four units of [Re(CO)3(bpy)]+ leads to an extremely facile reduction of TCNQ ligand. Hydride transfer catalysts are of technological importance (regeneration of NADH from NAD+, generators of hydrogen). Redox generated [RhCl(Cp)(bpy)] is used for this purpose. The catalytic reaction is based on a facile reaction of an intermediate with H+ yielding a hydride complex participating in the H-transfer itself. We scrutinized an alternative complex of 2,2'-bipyrimidine (instead of 2,2'-bipyridine) with emphasis on the mechanism of a dissociative intermediate formation [21]. Complexes [(MCl( 5-C5Me5)}2( -bpym)](PF6)2 (bpym = 2,2´-bipyrimidin; M = Rh, Ir) were obtained as pure isomers (M = Ir) or as a mixture of cis/trans isomers (M = Rh). The redox steps involving one to five electron transfers were followed by votammetry and by spectral methods (NMR, EPR, UV-VIS). Di-rhodium compound is step-wisely reduced by two electrons and disociatively looses chloride ligands yielding a highly reactive [(RhCl( 5-C5Me5)}2( -bpym)]. Di-iridium was found sufficiently stabile to dissociation even at -15 oC. Interpretation was aided by quantum chemical calculations [22,23] .
Derivatives of cymantren, [CpMn(CO)3 ], have suitable properties for binding to proteins. This offers an attractive application in protein analysis. Methyl carboxyimidate of cymantren is the suitable derivative. However, transition metal carbonyls are rather prone to ligand substitution in reduced state. Indeed, the one-electron reduction of cymantren in non-aqueous medium leads to the ligand dissociation and finally to a dimer formation. Side product of our work was a finding that a commercial high purity CO gas stored in steel tanks contains a substantial amount of volatile pentacarbonyl of iron formed at the tank walls. We designed and tested a reliable purification procedure [24]. The overall reaction scheme of cymanthrene reduction is rather complicated [25]. However, binding to bovine serum albumin brings a simplification caused by protecting hydrophobic environment of the protein molecule. Complexes of Pt(II) a Pt(IV) with diimine ligands yield intramolecular electron transfer connected with re-distribution of electrons between the ligands and central atoms which involves the lowest energy excited states [26]. A considerable photoreactivity was found in Pt(IV) complexes of the type [Pt(CH3)4( -diimine)] the excitation leads to the transfer of an electron (Cax-Pt-Cax) fragment to the alpha-diimine ligand [27,28,29] . Properties of new stable organorhenium radical complexes proved the importance of spin transfer from pi-acceptor bridging ligands over the central atom to the tail ligand. This mechanism plays a key role in photo and electrocatalytic reduction of CO2. This is its first experimental evidence [30]. Large amount of work on series of new poly-nuclear coordination compounds of platinum group metals was published. This research involved groups from D14 and D15 actions. The electron transfer and spectral properties in different oxidation states was interpreted in combination with TD-DFT methods. Aim of these studies was the determination of electron delocalization and the role of ligand structure [31,32,33,34,35,36]. The detection of intermediates with very short life-time required development of a non-standard methodology. This involved application of ultra-fast voltammetry on Au and Pt microelectrodes with electrode diameters 1-20 µm. We designed a new fast electronic device, performed tests of its bandwidth a developed controlling software. New experimental set-up enables voltammetric experiments with voltage scan rates up to 200 000 V/s (typical commercial instruments operate to 50 V/s) [37].

Joint publications
1.  L. Pospíšil, R. Sokolová, M.P. Colombini, S. Gianarelli, R. Fuoco J. Electroanal. Chem., 472 (1999) 33.
2.  L. Pospíšil, R. Sokolová, M.P. Colombini, S. Giannarelli, R. Fuoco Impedance spectroscopy of carboximide-type pesticides, in Urban    health: a challenge for the third millennium, Symposium on spectrochemistry, Siena, 1999, abstract p. 106.
3.  L. Pospíšil, R. Sokolová, M. Hromadová, S. Gianarelli, R. Fuoco, M.P. Colombini, J. Electroanal. Chem., 517 (2001) 28.
4.  M. Hromadová, L. Pospíšil, S. Gianarelli, R. Fuoco, M.P. Colombini Microchem. J., 73 (2002) 213.
5.  M. Hromadová, L. Pospíšil, S. Záliš, N. Fanelli, J. Incl. Phenom., 44 (2002) 373.
6.  M. Hromadová, L. Pospíšil, N. Fanelli, S. Giannarelli, Langmuir, submitted.
7.  L. Pospíšil, M. Hromadová, J. Fiedler, C. Amatore, J.-N. Verpeaux, J. Organometal. Chem., 668 (2003) 9.
8.  R. Sokolová, M. Hromadová, L. Pospíšil J. Electroanal. Chem., 552 (2003) 53.
9.  L. Pospíšil, S. Záliš, R. Sokolová, N. Fanelli Acta Chim. Hung.Models in Chem., 137 (2000) 383.
10.  N. Varaksa, L. Pospíšil, T. F. Magnera, J. Michl Proc. Natl. Acad. Sci. USA 99 (2002) 5012.
11.  M. Hromadová, M. Salmain, R. Sokolová, L. Pospíšil, G. Jaouen, J. Organometal. Chem., 668 (2003) 17.
12.  A. Klein, V. Kasack, R. Reinhardt, T. Sixt, T. Scheiring, S. Záliš, J. Fiedler, W. Kaim J.Chem.Soc., Dalton Trans., 1999, 575-582
13.  F. Baumann, W. Kaim, L.M. Baraldo, L.D. Slep, J.A. Olabe, J. Fiedler Inorg. Chim. Acta, 285 (1999) 129.
14.  F.M. Hornung, O. Heilmann, W. Kaim, S. Záliš, J. Fiedler, Inorg. Chem. 2000, 39, 4052.
15.  M. Albrecht, K. Hűbler, S. Záliš, W. Kaim Inorg. Chem. 2000, 39, 4731.
16.  H. Wadepohl, S. Gebert, H. Pritzkow, D. Osella, C. Nervi, J. Fiedler Eur. J. Inorg. Chem. 2000, 1833.
17.  J. Fiedler, C. Nervi, D. Osella, M.J. Calhorda, S.S.M.C. Godinho, R. Merkel, H. Wadepohl J. Chem. Soc., Dalton Trans. 2002, 3705
18.  E. Rosenberg, Md. J. Abedin, D. Rokshana, D. Osella, L. Millone, C. Nervi, J. Fiedler Inorg. Chim. Acta 2000, 300-302, 769.
19.  H. Hartmann, W. Kaim, I. Hartenbach, T. Schleid, M. Wanner, J. Fiedler Angew. Chem. Int. Ed., 40, 2842 2844 (2001).
20.  S. Berger, H. Hartmann, M. Wanner, J. Fiedler, W. Kaim, Inorg. Chim. Acta, 314 (2001), 22-26.
21.  W. Kaim, R. Reinhardt, S. Greulich, M. Sieger, J. Fiedler, Collection Czech. Chem. Commun., 66 (2001), 291-306
22.  M. Wanner, Scheiring T., Kaim W., Slep L.D., Baraldo L.M., Olabe J.A., Zalis S., Baerends E.J., Inorg. Chem., 40 (2001) 5704-5707.
23.  Rainer F. Winter, Karl-Wilhelm Klinkhammer and Stanislav Záliš, Organometallics, 20 (2001) 1317-1333.
24.  J. Fiedler, M. Salmain, G. Jaouen, L. Pospíšil, Inorg. Chem. Commun., 4 (2001)613.
25.  M. Salmain, G. Jaouen, J. Fiedler, R. Sokolová, L. Pospíšil, Coll. Czech. Chem. Commun., 66 (2001) 155.
26.  S. Dey, V. K. Jain, A. Knodler, A. Klein, W. Kaim, S. Záliš Inorg. Chem., 41 (2002) 2864-2870.
27.  J. Slageren, D. J. Stufkens, S. Záliš, A. Klein, J. Chem. Soc., Dalton Trans., 2002, 218.
28.  W. Kaim, A. Dogan, M. Wanner, A. Klein, I. Tiritiris, T. Schleid, D. J. Stufkens, T. L. Snoeck, E. J. L. McInnes, J. Fiedler, S. Záliš,        Inorg. Chem., 41 (2002) 4139-4148.
29.  J. van Slageren, A. Klein, S. Záliš, Coord. Chem. Reviews, 230 (2002) 193-211.
30.  S. Frantz, H. Hartmann, N. Doslik, M. Wanner, W. Kaim, H.-J. Kümmerer, G. Denninger, A.-L. Barra, C. Duboc-Toia, J. Fiedler,
      I. Ciofini, C. Urban, M. Kaupp: J. Am. Chem. Soc., 35 (2002), 10563-10571.
31.  Klein A., van Slageren J., Záliš S. Eur. J. Inorg. Chem. 2003, 1927-1938.
32.  R. F. Winter, S. Hartmann, S. Záliš, K. W. Klinkhammer J. Chem. Soc.,Dalton Trans., 2003, 2342-2352.
33.  H. Hartmann, W. Kaim, M. Wanner, A. Klein, S. Frantz, C. Duboc-Toia, J. Fiedler, S. Záliš Inorg. Chem., 42 (2003) 7018-7025.
34.  S. Záliš, M. Sieger, S. Greulich, H. Stoll, W. Kaim Inorg. Chem., 42 (2003) 5185-5191.
35.  W. Kaim, N. Doslik, S. Frantz, T. Sixt, M. Wanner, F. Baumann, G. Denninger, H. J. Kümmerer, C. Duboc-Toia, J. Fiedler, S. Záliš
     J. Mol. Struct. 656 (2003) 183-194.
36.  S. Ye, W. Kaim, B. Sarkar, B. Schwederski, F. Lissner, T. Schleid, C. Duboc-Toia, J. Fiedler Inorg. Chem. Commun. 6 (2003) 1196
37.  L. Pospíšil, J. Fiedler, N. Fanelli Rev. Sci. Instruments 71 (2000) 1804.