The imidazolium trans-tetrachloro(dimethylsulfoxide)imidazoleruthenate(III) complex [ImH][Ru(III)... more The imidazolium trans-tetrachloro(dimethylsulfoxide)imidazoleruthenate(III) complex [ImH][Ru(III)Cl(4)(DMSO)(Im)], NAMI-A, has shown an interesting antimetastatic activity. Since Ru(III) complexes are coordinatively more inert than the corresponding Ru(II) derivatives, an "activation by reduction" mechanism has been proposed to explain the biological activity of NAMI-A, thus acting as a pro-drug. We report here an electrochemical study on NAMI-A in aqueous solutions which emphasizes the structural and chemical consequences accompanying the easy Ru(III)/Ru(II) electron transfer (e.g., axial imidazole/water exchange in acidic solution in the short timescale of cyclic voltammetry followed by equatorial chloride/water exchange in the longer timescale of macroelectrolysis).
The cover picture shows the X-ray structure of [Pd(Et2timdt)Br2] (left; Et2timdt = diethylimidazo... more The cover picture shows the X-ray structure of [Pd(Et2timdt)Br2] (left; Et2timdt = diethylimidazolidine-2,4,5-trithione), obtained by treating the symmetrically substituted dithiolene [Pd(Et2timdt)2] with Br2 or IBr. This complex has been exploited as a starting material for the synthesis of the new mixed-ligand, push-pull dithiolene [Pd(Et2timdt)(mnt)] (mnt = maleonitriledithiolate), whose X-ray molecular structure is depicted on the right. Details are discussed in the Short Communication by M. Arca et al. on p. 1291 ff.
Albinati, A., Fabrizi de Biani, F., Leoni, P., Marchetti, L., Pasquali, M., Rizzato, S. and Zanel... more Albinati, A., Fabrizi de Biani, F., Leoni, P., Marchetti, L., Pasquali, M., Rizzato, S. and Zanello, P.(2005), Redox Control of Light-Induced Platinum-Cluster-to-Iron Charge Transfer in a Bis (ferrocenylethynyl)-Substituted Hexanuclear Platinum Derivative. Angewandte Chemie ...
Useful synthons containing the tribridged triangular unit {Pt(3)} = [Pt(3)(mu-P(t)Bu(2))(3)](+) w... more Useful synthons containing the tribridged triangular unit {Pt(3)} = [Pt(3)(mu-P(t)Bu(2))(3)](+) were prepared starting from the known tricarbonyl derivative [{Pt(3)}(CO)(3)]Z, [(1(+))Z, Z = CF(3)SO(3)(-)]. This was easily converted into the monohalides {Pt(3)}(CO)(2)X [2, X = Cl; 3, X = Br; 4, X = I], by reaction with the appropriate halide salt. The coupling reaction between 2 and terminal alkynes in the presence of CuI afforded in good yields the sigma-alkynyl derivatives {Pt(3)}(CO)(2)(CC-R) [6, R = SiMe(3); 7, R = CC-SiMe(3); 8, R = C(6)H(5); 9, R = C(6)H(4)-4-Br; 10, R = C(6)H(4)-4-CCH; 11, R = 2-C(4)H(2)S-5-CCH; 12, R = 9-C(14)H(8)-10-CCH], while desilylation of 6 or 7 with TBAF/THF gave, respectively, the derivatives 13 (R = H) and 14 (R = CCH). The stepwise elongation of the arylalkynyl chain was obtained by the Sonogashira coupling of 10 with an excess of 1,4-diiodobenzene, which produced 15 (R = C(6)H(4)-4-CC-C(6)H(4)-4-I), and by coupling the latter with an excess of 1,4-...
The electrochemistry of a series of nickel(II), copper(II), cobalt(II), manganese(II) and oxovana... more The electrochemistry of a series of nickel(II), copper(II), cobalt(II), manganese(II) and oxovanadium(IV) complexes with theN,N'-1,2-phenylenebis(salicylideneimin)ate ligand has been studied in dimethyl sulfoxide solution. Kinetic and thermodynamic aspects of the electron-transfer processes are discussed, also with respect to those of the correspondingN,N'-ethylenebis(salicylideneimin)ate and bis(salicylideneiminate-3-propyl)amine derivatives
ABSTRACT The 46 e cluster Os3(mu-H)2(CO)10 exhibits a very complex redox behavior. Its cyclic vol... more ABSTRACT The 46 e cluster Os3(mu-H)2(CO)10 exhibits a very complex redox behavior. Its cyclic voltammetric (CV) response consists of two reduction peaks, the latter having an adsorption character. Polarographic, coulometric, and spectroscopic data indicate that the initially electrogenerated monoanion [Os3H2(CO)10]- undergoes several chemical side reactions, one being an irreversible cluster breakdown and the others being dimerization reactions. The adducts Os3(H)(mu-H)(CO)10L with Lewis bases (L = CO, PPh3, AsPh3) exhibit a single 2e, chemically irreversible reduction process at more negative potentials than Os3H2(CO)10. Their electrochemical behavior is similar to that of the saturated cluster Os3(CO)12. Elimination of one CO on thermolysis produces Os3H2(CO)9L (L = PPh3, AsPh3) where the unsaturated system Os-H-2-Os is restored; accordingly its CV response is very similar to that of the parent compound, Os3H-2(CO)10.
ABSTRACT A collection of nickelocene and cobaltocene analogs with one or two nickelafluorenyl rin... more ABSTRACT A collection of nickelocene and cobaltocene analogs with one or two nickelafluorenyl rings has been recently synthesized starting from 9-nickelafluorenyllithium complex. The redox ability of the whole series of derivates has been investigated by electrochemical techniques, and the nature of the frontier orbitals responsible for the electron transfer activity of this class of compounds has been supported by extended Hückel calculations.
... Sect. A:, 46 (1990) 467. [13] GM Sheldrick, SHELXL93 Program for Crystal Structure Re finemen... more ... Sect. A:, 46 (1990) 467. [13] GM Sheldrick, SHELXL93 Program for Crystal Structure Re finement, University of Gottingen, Germany, 1993. [14] NPC Walker and D. Stuart, Acta Crystallogr. Sect. ... [14]. NPC Walker and D. Stuart. Acta Crystallogr. Sect. ...
The oxidation of the [Fe(CO)4]2- dianion with Ag+ salts occurs through a particularinner-sphere m... more The oxidation of the [Fe(CO)4]2- dianion with Ag+ salts occurs through a particularinner-sphere mechanism, which involves an intermediate cascade of silver clusters stabilized by Fe(CO)4 ligands. The last detectable Ag-Fe cluster of the sequence is the [Ag13{µ-Fe(CO)4}8]3- trianion, which has been selectively obtained by using ca. 1.7 equivalents of Ag+ per mole of [Fe(CO)4]2-. The [Ag13{µ-Fe(CO)4}8]3-- trianion has been isolated
... a , John Desper a , Piero Zanello E-mail The Corresponding Author , b , Arnaldo Cinquantini b... more ... a , John Desper a , Piero Zanello E-mail The Corresponding Author , b , Arnaldo Cinquantini b , Maddalena Corsini b and Marco Fontani b. ... for the different diferrocenes in that such a parameter allows a quick evaluation of the nature of the relative mixed-valent species through ...
Following previous reports on the synthesis and structure of different nickelacyclic complexes an... more Following previous reports on the synthesis and structure of different nickelacyclic complexes analogues of nickelocene, we now deal with the new metallacyclic compounds (eta5-R-cyclopentadienyl){eta4-[1-(eta5-R-cyclopentadienyl)]-2,3,4,5-tetraphenyl-1-nickela-2-cyclopentenyl}nickel (R = H, CH3). The redox ability of the whole series of nickelacyclic derivatives has been also investigated by electrochemical and spectroelectrochemical techniques, and the nature of the frontier orbitals responsible for the rich electron transfer activity of this class of compounds has been supported by theoretical considerations. On the basis of the redox properties of a few neutral members of the series, their chemical oxidation afforded the corresponding monocations and the crystal structures of the pertinent redox couples were determined by X-ray single-crystal analysis.
... Pasquale Piraino,*t Giuseppe Bruno,t Sandra Lo %hiavo,+ Franco Laschi,* and Piero Zanello*t R... more ... Pasquale Piraino,*t Giuseppe Bruno,t Sandra Lo %hiavo,+ Franco Laschi,* and Piero Zanello*t Received August 5, 1986 The reaction of the ... the Rh(II1)-Rh(II1) specie^.^ While the tetrakis(ani1ino-pyridinato) complex Rhz(PhNpyr)44 and the tetrakis(benz-amidinato) complex ...
The imidazolium trans-tetrachloro(dimethylsulfoxide)imidazoleruthenate(III) complex [ImH][Ru(III)... more The imidazolium trans-tetrachloro(dimethylsulfoxide)imidazoleruthenate(III) complex [ImH][Ru(III)Cl(4)(DMSO)(Im)], NAMI-A, has shown an interesting antimetastatic activity. Since Ru(III) complexes are coordinatively more inert than the corresponding Ru(II) derivatives, an "activation by reduction" mechanism has been proposed to explain the biological activity of NAMI-A, thus acting as a pro-drug. We report here an electrochemical study on NAMI-A in aqueous solutions which emphasizes the structural and chemical consequences accompanying the easy Ru(III)/Ru(II) electron transfer (e.g., axial imidazole/water exchange in acidic solution in the short timescale of cyclic voltammetry followed by equatorial chloride/water exchange in the longer timescale of macroelectrolysis).
The cover picture shows the X-ray structure of [Pd(Et2timdt)Br2] (left; Et2timdt = diethylimidazo... more The cover picture shows the X-ray structure of [Pd(Et2timdt)Br2] (left; Et2timdt = diethylimidazolidine-2,4,5-trithione), obtained by treating the symmetrically substituted dithiolene [Pd(Et2timdt)2] with Br2 or IBr. This complex has been exploited as a starting material for the synthesis of the new mixed-ligand, push-pull dithiolene [Pd(Et2timdt)(mnt)] (mnt = maleonitriledithiolate), whose X-ray molecular structure is depicted on the right. Details are discussed in the Short Communication by M. Arca et al. on p. 1291 ff.
Albinati, A., Fabrizi de Biani, F., Leoni, P., Marchetti, L., Pasquali, M., Rizzato, S. and Zanel... more Albinati, A., Fabrizi de Biani, F., Leoni, P., Marchetti, L., Pasquali, M., Rizzato, S. and Zanello, P.(2005), Redox Control of Light-Induced Platinum-Cluster-to-Iron Charge Transfer in a Bis (ferrocenylethynyl)-Substituted Hexanuclear Platinum Derivative. Angewandte Chemie ...
Useful synthons containing the tribridged triangular unit {Pt(3)} = [Pt(3)(mu-P(t)Bu(2))(3)](+) w... more Useful synthons containing the tribridged triangular unit {Pt(3)} = [Pt(3)(mu-P(t)Bu(2))(3)](+) were prepared starting from the known tricarbonyl derivative [{Pt(3)}(CO)(3)]Z, [(1(+))Z, Z = CF(3)SO(3)(-)]. This was easily converted into the monohalides {Pt(3)}(CO)(2)X [2, X = Cl; 3, X = Br; 4, X = I], by reaction with the appropriate halide salt. The coupling reaction between 2 and terminal alkynes in the presence of CuI afforded in good yields the sigma-alkynyl derivatives {Pt(3)}(CO)(2)(CC-R) [6, R = SiMe(3); 7, R = CC-SiMe(3); 8, R = C(6)H(5); 9, R = C(6)H(4)-4-Br; 10, R = C(6)H(4)-4-CCH; 11, R = 2-C(4)H(2)S-5-CCH; 12, R = 9-C(14)H(8)-10-CCH], while desilylation of 6 or 7 with TBAF/THF gave, respectively, the derivatives 13 (R = H) and 14 (R = CCH). The stepwise elongation of the arylalkynyl chain was obtained by the Sonogashira coupling of 10 with an excess of 1,4-diiodobenzene, which produced 15 (R = C(6)H(4)-4-CC-C(6)H(4)-4-I), and by coupling the latter with an excess of 1,4-...
The electrochemistry of a series of nickel(II), copper(II), cobalt(II), manganese(II) and oxovana... more The electrochemistry of a series of nickel(II), copper(II), cobalt(II), manganese(II) and oxovanadium(IV) complexes with theN,N'-1,2-phenylenebis(salicylideneimin)ate ligand has been studied in dimethyl sulfoxide solution. Kinetic and thermodynamic aspects of the electron-transfer processes are discussed, also with respect to those of the correspondingN,N'-ethylenebis(salicylideneimin)ate and bis(salicylideneiminate-3-propyl)amine derivatives
ABSTRACT The 46 e cluster Os3(mu-H)2(CO)10 exhibits a very complex redox behavior. Its cyclic vol... more ABSTRACT The 46 e cluster Os3(mu-H)2(CO)10 exhibits a very complex redox behavior. Its cyclic voltammetric (CV) response consists of two reduction peaks, the latter having an adsorption character. Polarographic, coulometric, and spectroscopic data indicate that the initially electrogenerated monoanion [Os3H2(CO)10]- undergoes several chemical side reactions, one being an irreversible cluster breakdown and the others being dimerization reactions. The adducts Os3(H)(mu-H)(CO)10L with Lewis bases (L = CO, PPh3, AsPh3) exhibit a single 2e, chemically irreversible reduction process at more negative potentials than Os3H2(CO)10. Their electrochemical behavior is similar to that of the saturated cluster Os3(CO)12. Elimination of one CO on thermolysis produces Os3H2(CO)9L (L = PPh3, AsPh3) where the unsaturated system Os-H-2-Os is restored; accordingly its CV response is very similar to that of the parent compound, Os3H-2(CO)10.
ABSTRACT A collection of nickelocene and cobaltocene analogs with one or two nickelafluorenyl rin... more ABSTRACT A collection of nickelocene and cobaltocene analogs with one or two nickelafluorenyl rings has been recently synthesized starting from 9-nickelafluorenyllithium complex. The redox ability of the whole series of derivates has been investigated by electrochemical techniques, and the nature of the frontier orbitals responsible for the electron transfer activity of this class of compounds has been supported by extended Hückel calculations.
... Sect. A:, 46 (1990) 467. [13] GM Sheldrick, SHELXL93 Program for Crystal Structure Re finemen... more ... Sect. A:, 46 (1990) 467. [13] GM Sheldrick, SHELXL93 Program for Crystal Structure Re finement, University of Gottingen, Germany, 1993. [14] NPC Walker and D. Stuart, Acta Crystallogr. Sect. ... [14]. NPC Walker and D. Stuart. Acta Crystallogr. Sect. ...
The oxidation of the [Fe(CO)4]2- dianion with Ag+ salts occurs through a particularinner-sphere m... more The oxidation of the [Fe(CO)4]2- dianion with Ag+ salts occurs through a particularinner-sphere mechanism, which involves an intermediate cascade of silver clusters stabilized by Fe(CO)4 ligands. The last detectable Ag-Fe cluster of the sequence is the [Ag13{µ-Fe(CO)4}8]3- trianion, which has been selectively obtained by using ca. 1.7 equivalents of Ag+ per mole of [Fe(CO)4]2-. The [Ag13{µ-Fe(CO)4}8]3-- trianion has been isolated
... a , John Desper a , Piero Zanello E-mail The Corresponding Author , b , Arnaldo Cinquantini b... more ... a , John Desper a , Piero Zanello E-mail The Corresponding Author , b , Arnaldo Cinquantini b , Maddalena Corsini b and Marco Fontani b. ... for the different diferrocenes in that such a parameter allows a quick evaluation of the nature of the relative mixed-valent species through ...
Following previous reports on the synthesis and structure of different nickelacyclic complexes an... more Following previous reports on the synthesis and structure of different nickelacyclic complexes analogues of nickelocene, we now deal with the new metallacyclic compounds (eta5-R-cyclopentadienyl){eta4-[1-(eta5-R-cyclopentadienyl)]-2,3,4,5-tetraphenyl-1-nickela-2-cyclopentenyl}nickel (R = H, CH3). The redox ability of the whole series of nickelacyclic derivatives has been also investigated by electrochemical and spectroelectrochemical techniques, and the nature of the frontier orbitals responsible for the rich electron transfer activity of this class of compounds has been supported by theoretical considerations. On the basis of the redox properties of a few neutral members of the series, their chemical oxidation afforded the corresponding monocations and the crystal structures of the pertinent redox couples were determined by X-ray single-crystal analysis.
... Pasquale Piraino,*t Giuseppe Bruno,t Sandra Lo %hiavo,+ Franco Laschi,* and Piero Zanello*t R... more ... Pasquale Piraino,*t Giuseppe Bruno,t Sandra Lo %hiavo,+ Franco Laschi,* and Piero Zanello*t Received August 5, 1986 The reaction of the ... the Rh(II1)-Rh(II1) specie^.^ While the tetrakis(ani1ino-pyridinato) complex Rhz(PhNpyr)44 and the tetrakis(benz-amidinato) complex ...
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