Serena Fedi

University of Bologna, Bologna, Emilia-Romagna, Italy

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Publications (26)87.92 Total impact

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    ABSTRACT: Cationic triple-decker complexes with a bridging diborolyl ligand, [CpCo(μ-1,3-C3B2Me5)M(ring)]+ (M(ring) = CoCp (2a), CoCp* (2b), RhCp (3a), RhCp* (3b), IrCp (4a), IrCp* (4b), Ru(C6H6) (5a), Ru(p-MeC6H4Pri) (5b), Ru(C6Me6) (5c), Ru(η6-cycloheptatriene) (6)), were synthesized by reaction of CpCo(μ-1,3-C3B2Me5)Tl with [M(ring)Hal2]2. The structures of 2aBPh4, 2bPF6, 4aPF6, 5aOTf, and 5cPF6 were determined by X-ray diffraction. The electron-transfer ability of the complexes has been ascertained by electrochemical and spectroelectrochemical techniques. In general, they are able to shuttle reversibly in the sequence 2+/+/0/–, plausibly affording completely delocalized mixed-valence derivatives. DFT calculations revealed structural changes accompanying redox processes and satisfactorily predicted the potentials for the first reduction and first oxidation.
    Organometallics 04/2013; 32(9):2713–2724. · 4.15 Impact Factor
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    ABSTRACT: The anionic cluster [Pt(19)(CO)(22)](4-) (1), of pentagonal symmetry, reacts with CO and AuPPh(3)(+) fragments. Upon increasing the Au:Pt(19) molar ratio, different species are sequentially formed, but only the last two members of the series could be characterized by X-ray diffraction, namely, [Pt(19)(CO)(24)(μ(4)-AuPPh(3))(3)](-) (2) and [Pt(19)(CO)(24){μ(4)-Au(2)(PPh(3))(2)}(2)] (3). The metallic framework of the starting cluster is completely modified after the addition of CO and AuL(+), and both products display the same platinum core of trigonal symmetry, with closely packed metal atoms. The three AuL(+) units cap three different square faces in 2, whereas four AuL(+) fragments are grouped in two independent bimetallic units in the neutral cluster 3. Electrochemical and spectroelectrochemical studies on 2 showed that its redox ability is comparable with that of the homometallic 1.
    Inorganic Chemistry 01/2013; · 4.59 Impact Factor
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    ABSTRACT: A detailed study of the reaction between [Ni(6)(CO)(12)](2-) and [AuCl(4)](-) afforded the isolation of the new Ni-Au cluster [Ni(12)Au(CO)(24)](3-) as well as identifying an improved synthesis for the previously reported [Ni(32)Au(6)(CO)(44)](6-). The new [Ni(12)Au(CO)(24)](3-) cluster is composed by two [Ni(6)(CO)(12)](2-) moieties coordinated to a central Au(I) ion, as determined by X-ray diffraction. It is noteworthy that the two [Ni(6)(CO)(12)](2-) fragments display different geometries, i.e., trigonal antiprismatic (distorted octahedral) and distorted trigonal prismatic (monocapped square pyramidal). The chemical reactivity of these clusters and their electrochemical behavior have been studied. [Ni(12)Au(CO)(24)](3-) is irreversibly transformed, upon electrochemical reduction, into Au(0) and [Ni(6)(CO)(12)](2-), followed by the reversible reduction of the latter homometallic cluster. Conversely, [Ni(32)Au(6)(CO)(44)](6-) displays five reductions, with apparent features of reversibility, confirming the ability of larger metal carbonyl clusters to reversibly accept and release electrons.
    Inorganic Chemistry 10/2012; · 4.59 Impact Factor
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    ABSTRACT: Six metal carbido-carbonyl clusters have been isolated and recognized as members of a multivalent family based on the dioctahedral Rh(10)(C)(2) frame, with variable numbers of CO ligands, AuPPh(3) moieties, and anionic charge: [Rh(10)(C)(2)(CO)(x)(AuPPh(3))(y)](n-) (x = 18, 20; y = 4, 5, 6; n = 0, 1, 2). Anions [Rh(10)(C)(2)(CO)(18)(AuPPh(3))(4)](-) ([2](-)) and [Rh(10)(C)(2)(CO)(18)(AuPPh(3))(4)](2-) ([2](2-)) have been obtained by the reduction of [Rh(10)(C)(2)(CO)(18)(AuPPh(3))(4)] (2) under N(2), while [Rh(10)(C)(2)(CO)(18)(AuPPh(3))(5)](-) ([3](-)) was obtained from [Rh(10)(C)(2)(CO)(20)(AuPPh(3))(4)] (1) by reduction under a CO atmosphere. [3](-) can be better obtained by the addition of AuPPh(3)Cl to [2](2-). [Rh(10)(C)(2)(CO)(18)(AuPPh(3))(6)] (4) is obtained from [3](-) and 2 as well by the reduction and subsequent addition of AuPPh(3)Cl. The molecular structures of [2](2-) ([NBu(4)](+) salt), [3](-) ([NMe(4)](+) salt), and 4 have been determined by single-crystal X-ray diffraction. The redox activities of complexes 1, 2 and [3](-) have been investigated by electrochemical and electron paramagnetic resonance (EPR) techniques. The data from EPR spectroscopy have been accounted for by theoretical calculations.
    Inorganic Chemistry 08/2012; 51(17):9171-80. · 4.59 Impact Factor
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    ABSTRACT: Geminal bisphosphonates (BPs), used in the clinic for the treatment of hypercalcaemia and skeletal metastases, have been also exploited for promoting the specific accumulation of platinum antitumor drugs in bone tissue. In this work, the platinum dinuclear complex [{Pt(en)}(2)(μ-AHBP-H(2))](+) (1) (the carbon atom bridging the two phosphorous atoms carrying a 2-ammonioethyl and a hydroxyl group, AHBP-H(2)) has been used as scaffold for the synthesis of a Pt(II) trinuclear complex, [{Pt(en)}(3)(μ-AHBP)](+) (2), and a Pt(IV) adamantane-shaped dinuclear complex featuring an oxo-bridge, [{Pt(IV)(en)Cl}(2)(μ-O)(μ-AHBP-H(2))](+) (3) (X-ray structure). Compound 2 undergoes a reversible, pH dependent, rearrangement with a neat switch point around pH = 5.4. Compound 3 undergoes a one-step electrochemical reduction at E(pc) = -0.84 V affording compound 1. Such a potential is far lower than that of glutathione (-0.24 V), nevertheless compound 3 can undergo chemical reduction to 1 by GSH, most probably through a different (inner-sphere) mechanism. In vitro cytotoxicity of the new compounds, tested against murine glioma (C6) and human cervix (HeLa) and hepatoma (HepG2) cell lines, has shown that, while the Pt(IV) dimer 3 is inactive up to a concentration of 50 μM, the two Pt(II) polynuclear compounds 1 and 2 have a cytotoxicity comparable to that of cisplatin with the trinuclear complex 2 generally more active than the dinuclear complex 1.
    Dalton Transactions 07/2012; 41(32):9689-99. · 3.81 Impact Factor
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    ABSTRACT: The chemical reduction of [Co8Pt4C2(CO)24]2– ([1]2–) with Na/naphthalene results, after workup, in the isolation of either [Co10Pt2C2(CO)22]4– ([2]4–) or [Co8Pt4C2(CO)20]4– ([3]4–), depending on the experimental conditions. All these species undergo several chemical and/or electrochemical redox reactions, disclosing the existence of structurally related dodecanuclear clusters [1]n– (n = 0–4), [2]n– (n = 2–6) and [3]n–(n = 1–7). In the attempt to isolate more reduced species,[1]n–, [2]n– and [3]n– undergo structural rearrangements resulting, among others, in the formation of the new species [Co10–xPt2+xC2(CO)24]2– ([4]2–) (x = 0–2) structurally related to [1]2–. These dodecanuclear M12C2 dicarbido clusters are not isostructural and differ in the metal composition and/or the number of CO ligands. Nevertheless, they can be readily interconverted even if the interconversion reactions are not straightforward.
    Berichte der deutschen chemischen Gesellschaft 05/2012; 2012(13). · 2.94 Impact Factor
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    ABSTRACT: The reactions of [NEt(4)](2)[Ni(6)(CO)(12)] with miscellaneous carbon halides (e.g. CCl(4), C(4)Cl(6)) in CH(2)Cl(2) have been extensively investigated particularly focusing on the stoichiometric ratio of the reagents and reaction temperature. This allowed the preparation of the previously known acetylide clusters [Ni(16)(C(2))(2)(CO)(23)](4-), [HNi(25)(C(2))(4)(CO)(32)](3-) and [Ni(22)(C(2))(4)(CO)(28)Cl](3-), as well as isolation and full characterisation of the closely related [Ni(17)(C(2))(2)(CO)(24)](4-) and [Ni(25)(C(2))(4)(CO)(32)](4-) tetraanions. From a structural point of view, all these clusters are based on a Ni(16) square orthobicupola which contain interstitial C(2), Ni(η(2)-C(2))(4) or Ni(2)(μ-η(2)-C(2))(4) moieties, displaying rather short C-C bonds. Electrochemical studies reveal that all these species undergo different redox processes, even if their stability is rather limited. This is corroborated by an extensive analysis of the interaction between interstitial C(2) acetylide units and the metal cluster cage by Extended Huckel Molecular Orbital (EHMO) calculations, which indicates that tightly bonded C-C units are less effective than isolated C-atoms in stabilising the cluster cage.
    Dalton Transactions 02/2012; 41(15):4649-63. · 3.81 Impact Factor
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    ABSTRACT: The 86-electron dicationic octahedral rhodium clusters containing Cp (Cp = C5H5) ligands and either an interstitial carbon atom, [Rh6Cp6(μ6-C)]2+ ([1]2+), or two carbonyl groups, [Rh6Cp6(μ3-CO)2]2+ ([2]2+), were synthesized in low yields by reactions of Rh3Cp3(μ-CO)3 with RhCp(C2H4)2 or [RuCp∗(MeCN)3]+ (Cp∗ = C5Me5), respectively. The structures of [1]2+ and [2]2+ were determined by X-ray diffraction. Their electrochemical behavior proved that they possess a rather extended electron transfer activity. In accordance with DFT calculations, the nearly octahedral structure of [1]2+ and [2]2+ is retained both upon oxidation (2+/3+) and the first reduction (2+/+); however, the second reduction (+/0) results in the breaking of one (for [1]0) or two (for [2]0) Rh–Rh bonds. In the case of the related Dahl’s nickel cluster Ni6Cp6 the nearly octahedral structure is retained upon all redox steps (3+/2+/+/0/−/2−).
    Additives for Polymers 08/2011; 374(1):313–319.
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    ABSTRACT: The halide ligands of [Fe(4)C(CO)(12)(CuCl)(2)](2-) (1) and [Fe(5)C(CO)(14)CuCl](2-) (2) can be displaced by N-, P- or S-donors. Beside substitution, the clusters easily undergo structural rearrangements, with loss/gain of metal atoms, and formation of Fe(4)Cu/Fe(4)Cu(3) metallic frameworks. Thus, the reaction of 1 with excess dppe yielded [{Fe(4)C(CO)(12)Cu}(2)(μ-dppe)](2-) (3). [{Fe(4)C(CO)(12)Cu}(2)(μ-pyz)](2-) (4) was obtained by reaction of 2 with Ag(+) and pyrazine. [Fe(4)C(CO)(12)Cu-py](-) (5) was formed more directly from [Fe(4)C(CO)(12)](2-), [Cu(NCMe)(4)](+) and pyridine. [Fe(4)Cu(3)C(CO)(12)(μ-S(2)CNEt(2))(2)](-) (6) and [{Fe(4)Cu(3)C(CO)(12)(μ-pz)(2)}(2)](2-) (7) were prepared by substitution of the halides of 1 with diethyldithiocarbamate and pyrazolate, in the presence of Cu(i) ions. All of these products were characterized by X-ray analysis. 3 and 4 and 5 are square based pyramids, with iron in the apical sites, the bridging ligands connect the two copper atoms in 3 and 4. 6 and 7 are octahedral clusters with an additional copper ion held in place by the two bridging anionic ligands, forming a Cu(3) triangle with Cu-Cu distances ranging 2.63-3.13 Å. In 7, an additional unbridged cuprophilic interaction (2.75 Å) is formed between two such cluster units. DFT calculations were able to reproduce the structural deformations of 3-5, and related their differences to the back-donation from the ligand to Cu. Additionally, DFT found that, in solution, the tight ion pair [NEt(4)](2)7 is almost isoenergetic with the monomeric form. Thus, 3, 4 and 7 are entities of nanometric size, assembled either through conventional metal-ligand bonds or weaker electrostatic interactions. None of them allows electronic communication between the two monomeric units, as shown by electrochemistry and spectroelectrochemical studies. (dppe = PPh(2)CH(2)CH(2)PPh(2), pyz = pyrazine C(4)N(2)H(4), py = pyridine C(5)H(5)N, pz = pyrazolate C(3)N(2)H(3)(-)).
    Dalton Transactions 04/2011; 40(20):5464-75. · 3.81 Impact Factor
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    ABSTRACT: New Mo(II) complexes with 2,2′-dipyridylamine (L1), [Mo(CH3CN)(η3-C3H5)(CO)2(L1)]OTf (C1a) and [{MoBr(η3-C3H5)(CO)2(L1)}2(4,4′-bipy)](PF6)2 (C1b), with {[bis(2-pyridyl)amino]carbonyl}ferrocene (L2), [MoBr(η3-C3H5)(CO)2(L2)] (C2), and with the new ligand N,N-bis(ferrocenecarbonyl)-2-aminopyridine (L3), [MoBr(η3-C3H5)(CO)2(L3)] (C3), were prepared and characterized by FTIR and 1H and 13C NMR spectroscopy. C1a, C1b, L3, and C2 were also structurally characterized by single crystal X-ray diffraction. The Mo(II) coordination sphere in all complexes features the facial arrangement of allyl and carbonyl ligands, with the axial isomer present in C1a and C2, and the equatorial in the binuclear C1b. In both C1a and C1b complexes, the L1 ligand is bonded to Mo(II) through the nitrogen atoms and the NH group is involved in hydrogen bonds. The X-ray single crystal structure of C2 shows that L2 is coordinated in a κ2-N,N-bidentate chelating fashion. Complex C3 was characterized as [MoBr(η3-C3H5)(CO)2(L3)] with L3 acting as a κ2-N,O-bidentate ligand, based on the spectroscopic data, complemented by DFT calculations.The electrochemical behavior of the monoferrocenyl and diferrocenyl ligands L2 and L3 has been studied together with that of their Mo(II) complexes C2 and C3. As much as possible, the nature of the different redox changes has been confirmed by spectrophotometric measurements. The nature of the frontier orbitals, namely the localization of the HOMO in Mo for both in C2 and C3, was determined by DFT studies.
    Journal of Organometallic Chemistry - J ORGANOMET CHEM. 01/2011; 696(10):2142-2152.
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    ABSTRACT: The reaction of [Ni10C2(CO)15]2– in thf with a large excess of CdCl2·2.5H2O (8–15 equiv.) resulted in the formation of the new carbonyl octacarbide clusters [H5–nNi36C8(CO)36(Cd2Cl3)]n– (n = 3–5), which undergo partial CO replacement to give [Ni36–yC8(CO)34–y(MeCN)3(Cd2Cl3)]3– (y = 0–2) after a prolonged time in MeCN. Treatment of the former with an excess of NaOH afforded the larger [H7–nNi42+yC8(CO)44+y(CdCl)]n– (n = 6, 7; y = 0, 1) octacarbides. Their structures (as well as those of the analogous Br-containing clusters) have been fully elucidated by single-crystal X-ray analysis of their [Me4N]5[Ni36C8(CO)36(Cd2Cl3)]·(7–2y)MeCN·yC6H14 (y = 0.40), [Me4N]3[Ni36–yC8(CO)34–y(MeCN)3(Cd2Cl3)]·5MeCN(y = 0.61), [Me4N]7[Ni42+yC8(CO)44+y(CdCl)]·(5–y)MeCN (y = 0.19) and [Me4N]6[HNi42+yC8(CO)44+y(CdBr)]·(6–y)MeCN (y = 0.19) salts, which feature highly distorted metal cages (due to the inclusion of several carbide atoms), and the presence of partially vacant capping Ni(CO) fragments. This aspect, together with the fact that all these species undergo several protonation–deprotonation equilibria in solution as well as reversible redox processes under electrochemical control, indicates that a detailed description of molecular species containing a few dozen metal atoms might be sometimes rather troublesome and non-trivial. A complete elucidation of these systems can be achieved only by combining structural, chemical, spectroscopic, electrochemical and spectroelectrochemical studies.
    Berichte der deutschen chemischen Gesellschaft 08/2010; 2010(30):4831 - 4842. · 2.94 Impact Factor
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    ABSTRACT: Reactions of 2,6-diacetylpyridine dioxime (dapdoH₂) with Mn(NO₃)₂ or Mn(SO₃CF₃)₂ under a variety of conditions or co-ligands yield compounds with the formula [Mn₆O₂(OMe)₂(dapdo)₂(dapdoH)₄](X)₂ in which X = NO₃⁻ (1) or SO₃CF₃⁻ (2), [Mn₈O₂(dapdo)₆(NO₃)₂]·H₂O (3) and [Mn(dapdoH₂)(N₃)₂](n) (4). Compounds 1, 3 and 4 were structurally characterized and equivalent structures for 1 and 2 were inferred from spectroscopic and analytical results. Compounds 1 and 2 consist of hexanuclear Mn₂(II)Mn₄(III) complexes whereas 3 consists of an octanuclear Mn₆(II)Mn₂(III) cluster in which the manganese atoms exhibit a rare bicapped elongated octahedral topology. Compound 4 consists of a 1D system bridged by double end-on azido ligands. Variable temperature magnetic studies were performed between 2-300 K, confirming the ground state S = 5 for 1 and 2, S = 0 for 3 and ferromagnetic response for 4.
    Dalton Transactions 05/2010; 39(20):4817-25. · 3.81 Impact Factor
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    ABSTRACT: The reactions between [Fe6C(CO)16]2− and CuCl, in refluxing THF, yield [Fe5C(CO)14(CuCl)]2− (1), [Fe4C(CO)12(CuCl)2]2− (2), or [{Fe4Cu2C(CO)12(μ-Cl)}2]2− (3), depending on the Fe6/CuCl ratio. The chloro ligands of these clusters can be displaced either spontaneously, or by metal-assisted substitution, to give the bromo derivative [Fe5C(CO)14(CuBr)]2− (4) or the solvento complexes [Fe5C(CO)14(CuTHF)]− (5) and [Fe4C(CO)12(CuNCMe)2] (6). The latter can be also obtained directly, by metal substitution from [Fe6C(CO)16]2− and [Cu(NCMe)4]BF4, or by polyhedral expansion from [Fe4C(CO)12]2−. All the clusters are octahedral, with the copper atoms in a pseudo-linear geometry, where one of the coordination positions is occupied by the interstitial carbide. The two copper atoms in the Fe4Cu2 clusters are always in cis geometry and, in the dimer [{Fe4Cu2C(CO)12(μ-Cl)}2]2−, they are joined through chlorides. The role of the different metal centres in determining the redox activity of the heteronuclear Fe–Cu clusters 1, 2, 3, has been studied by electrochemical methods. In the bridged dimer 3, the two Fe4Cu2C cluster units resulted electronically not communicating.
    Inorganica Chimica Acta 02/2010; 363(3):586–594. · 1.69 Impact Factor
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    ABSTRACT: The reaction of [Co(6)C(CO)(15)](2-) with 2 equiv of PtCl(2)(Et(2)S)(2) affords the new heterobimetallic [Co(8)Pt(4)C(2)(CO)(24)](2-), [1](2-), carbonyl cluster. [1](2-) undergoes reversible chemical and electrochemical oxidation and reduction processes disclosing a complete series of [1](n-) (n = 1-4) clusters. The mono- and dianion of [1](n-) have been isolated as their tetra-substituted ammonium salts and fully characterized by means of IR, (13)C NMR, ESI-MS, and X-ray crystallography. Variable-temperature (VT) solid-state EPR studies on pure crystalline samples indicate that both [1](2-) and [1](-*) are paramagnetic, due to a doublet state of the latter and a triplet state of [1](2-). This conclusion is supported by SQUID measurements on the same crystalline sample of [1](2-). The present study indisputably demonstrates that even-electron transition metal carbonyl clusters (TMCC) can be magnetic.
    Journal of the American Chemical Society 02/2010; 132(9):2919-27. · 10.68 Impact Factor
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    ABSTRACT: The redox properties of sumanene C(21)H(12) and its concave Fe(II) complex [(eta(5)-C(5)H(5))Fe(eta(6)-C(21)H(12))](+) have been elucidated through an electrochemical study in non-aqueous solvents, i.e. N,N-dimethylformamide (DMF) and acetonitrile (MeCN). The electron transfer activity of sumanene can be depicted as an irreversible oxidation and a partially chemically reversible one-electron reduction, both processes being located in proximity of the respective discharges of the solvents. The Fe(II) complex [(eta(5)-C(5)H(5))Fe(eta(6)-C(21)H(12))](PF(6)) in turn exhibits the Fe(II)/Fe(I) reduction, which in both DMF and MeCN solvents displays features of partial chemical reversibility, coupled to decomposition of the corresponding Fe(I) species [(eta(5)-C(5)H(5))Fe(eta(6)-C(21)H(12))] to fragments which, upon reoxidation, regenerate for the most part the original Fe(II)-sumanene species. In fact, among the fragments produced by exhaustive reduction, ESI measurements allowed the detection of ferrocene, the oxidation of which probably triggers the partial regeneration of the original Fe(II) complex. The pertinent PM6 semiempirical study accounts for the limited chemical reversibility of the redox processes exhibited by both sumanene and its Fe(II) complex.
    Dalton Transactions 11/2009; · 3.81 Impact Factor
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    ABSTRACT: Heating (80 degrees C) the electron-precise, Sn-centred, icosahedral cluster [Rh(12)Sn(CO)(27)](4-) under a nitrogen atmosphere affords in sequence the electron-deficient icosahedral [Rh(12)Sn(CO)(26)](4-) and [Rh(12)Sn(CO)(25)](4-) derivatives. The reaction is reversible in solution and the parent compound is quantitatively regenerated upon exposure to carbon monoxide. The reaction course has been unravelled via a combination of Band-target Entropy Minimization (BTEM) IR analysis and X-ray studies. While icosahedral clusters displaying electron counts formally exceeding 13 skeletal electron pairs (SEP) are known, [Rh(12)Sn(CO)(26)](4-) and [Rh(12)Sn(CO)(25)](4-) show for the first time that icosahedral clusters may also be stabilized with a deficiency of SEPs with respect to the requirement based on the cluster-borane analogy. In contrast to the behaviour of the electron-precise cluster [Rh(12)Sn(CO)(27)](4-), the electron-deficient cluster [Rh(12)Sn(CO)(25)](4-) undergoes reversible electrochemical reductions.
    Dalton Transactions 04/2009; · 3.81 Impact Factor
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    ABSTRACT: The reaction between [Fe2Ir2(CO)12]2− and diphenylacetylene in refluxing CH3CN yields the substituted cluster [Fe2Ir2(CO)10(PhC2Ph)]2− (1). In the crystals, the four metal atoms define a butterfly arrangement whose Ir–Ir hinge is parallel to the acetylenic C2 unit. The neutral triangular cluster [FeIr2(CO)9(PhC2Ph)] (2) is obtained by the treatment of 1 with acids at room temperature; in this 48 valence electrons species, the C–C and the Ir–Ir bonds are also parallel, in the μ3–η∥2 coordination mode.The cluster [Fe2Rh(CO)10]− reacts with diphenylacetylene in refluxing THF yielding [Fe2Rh(CO)8(PhC2Ph)]− (3). In this 46 C.V.E.’s cluster, the C2 unit is perpendicular to the Fe–Fe edge, exemplifying the μ3–η⊥2 bonding mode. According to 13C NMR spectra, the structure of the three clusters is maintained in solution. Electrochemical investigations show that the one-electron oxidation of [Fe2Ir2(CO)10(L)]2− (L=2CO, PhC2Ph) as well as the one-electron reduction of [Fe2Rh(CO)8(PhC2Ph)]− only generates the respective short lived products.
    Inorganica Chimica Acta 01/2009; 362(2):331-338. · 1.69 Impact Factor
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    ABSTRACT: The accurate study of the electron transfer activity of the tetraanion [Pt19(CO)22]4− is presented together with that of the dianion [Pt38(CO)44]2−, which was previously studied by spectroelectrochemistry but only partially examined from the electrochemical viewpoint. The main feature of the two clusters is that they undergo a sequence of close-spaced pairs of reversible one-electron processes, which are qualitatively reminiscent of those exhibited by the dianion [Pt24(CO)30]2−. In order to focus on such unique aspect of the three structurally characterised platinum clusters, we have investigated (and reinvestigated) their electrochemical and spectroelectrochemical redox properties, also reporting on the electron paramagnetic resonance (EPR) spectrum of the monoanion [Pt24(CO)30]−, which represents the first successful study of the paramagnetism of homoleptic platinum–carbonyl clusters.
    Journal of Solid State Electrochemistry 01/2009; 13(10):1497-1504. · 2.28 Impact Factor
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    ABSTRACT: Reaction of the [Ni(9)C(CO)(17)](2-) dianion with CdCl(2)2.5 H(2)O in THF affords the novel bimetallic Ni--Cd carbide carbonyl clusters [H(6-n)Ni(30)C(4)(CO)(34)(micro(5)-CdCl)(2)](n-) (n=3-6), which undergo several protonation-deprotonation equilibria in solution depending on the basicity of the solvent or upon addition of acids or bases. Although the occurrence in solution of these equilibria complicates the pertinent electrochemical studies on their electron-transfer activity, they clearly indicate that the clusters [H(6-n)Ni(30)C(4)(CO)(34)(micro(5)-CdCl)(2)](n-) (n=3-6), as well as the structurally related [H(6-n)Ni(34)C(4)(CO)(38)](n-) (n=4-6), undergo reversible or partially reversible redox processes and provide circumstantial and unambiguous evidence for the presence of hydrides for n=3, 4 and 5. Three of the [H(6-n)Ni(30)C(4)(CO)(34)(micro(5)-CdCl)(2)](n-) anions (n=4-6) have been structurally characterized in their [NMe(3)(CH(2)Ph)](4)[H(2)Ni(30)C(4)(CO)(34)(CdCl)(2)]2 COMe(2), [NEt(4)](5)[HNi(30)C(4)(CO)(34)(CdCl)(2)]2 MeCN and [NMe(4)](6)[Ni(30)C(4)(CO)(34)(CdCl)(2)]6 MeCN salts, respectively. All three anions display almost identical geometries and bonding parameters, probably because charge effects are minimized by delocalization over such a large metal carbonyl anion. Moreover, the Ni(30)C(4) core in these Ni-Cd carbide clusters is identical within experimental error to those present in the [HNi(34)C(4)(CO)(38)](5-) and [Ni(35)C(4)(CO)(39)](6-) species, suggesting that the stepwise assembly of their nickel carbide cores may represent a general pathway of growth of nickel polycarbide clusters. The fact that the [H(6-n)Ni(30)C(4)(CO)(34)(micro(5)-CdCl)(2)](n-)(n=4-6) anions display two valence electrons more than the structurally related [H(6-n)Ni(34)C(4)(CO)(38)](n-) (n=4-6) species has been rationalized by extended Hückel molecular orbital (EHMO) analysis.
    Chemistry 02/2008; 14(6):1924-34. · 5.83 Impact Factor
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    ABSTRACT: The dication [(eta6-C6Me6)Ru(eta6-C20H10)]2+ in propylene carbonate solution exhibits a sequence of reduction processes that is either metal-centered [Ru(II)/Ru(I)/Ru(0)] or ligand-centered. The marginally stable Ru(I) monocation [(eta6-C6Me6)Ru(eta6-C20H10)]+ has been characterized by EPR spectroscopy. The electrochemistry of C20H10 and EPR features of its stable monoanion [C20H10]- have also been revisited.
    Inorganic Chemistry 01/2008; 46(25):10901-6. · 4.59 Impact Factor

Publication Stats

37 Citations
87.92 Total Impact Points

Institutions

  • 2007–2012
    • University of Bologna
      • "Toso Montanari" Department of Industrial Chemistry CHIMIND
      Bologna, Emilia-Romagna, Italy
    • Università degli Studi di Bari Aldo Moro
      • Dipartimento di Chimica
      Bari, Apulia, Italy
  • 2005–2012
    • Università degli Studi di Siena
      Siena, Tuscany, Italy
  • 2011
    • Università degli Studi di Milano-Bicocca
      • Department of Earth and Environmental Sciences
      Milano, Lombardy, Italy
  • 2008
    • Iowa State University
      • Department of Chemistry
      Ames, IA, United States