Francesco Demartin

University of Milan, Milano, Lombardy, Italy

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Publications (324)886.92 Total impact

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    ABSTRACT: We report on an experimental investigation of the magnetic and structural properties of the Y2-xZnxRu2O7 pyrochlore system as a function of the Zn doping in the range 0.00 ≤ x ≤ 0.20. Magnetization and muon spin relaxation measurements show that the antiferromagnetic transition typical of the undoped compound at TN = 77 K is slightly reduced and broadened in the Zn doped sample. Extended X-ray absorption fine structure measurements show a peak in the Ru-O(1) first shell Debye-Waller factor at a temperature TDW ≈ TN, giving evidence for a strong magnetoelastic coupling detected up to x = 0.10. A local precursor order-disorder transition at T∗ > TN is also observed up to x = 0.10. For x > 0.10 these local structural features are hidden due to the increasing local lattice distortion induced by the Zn2+ dopant whereas the magnetic transition is still present.
    No preview · Article · Nov 2015 · RSC Advances
  • Francesco Demartin · Carlo Castellano · Carlo Maria Gramaccioli
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    ABSTRACT: The new mineral campostriniite, (Bi3+,Na)3(NH4,K)2Na2(SO4)6·H2O, was found in an active fumarole (fumarole FA, temperature ∼350°C) at La Fossa Crater, Vulcano, Aeolian Islands, Sicily, Italy. It occurs on a pyroclastic breccia as white prismatic crystals up to 0.2 mm long, in association with adranosite, demicheleite-(Br), demicheleite-(I), argesite and sassolite. The mineral is monoclinic, space group: C2/c (no. 15) with a = 17.748(3), b = 6.982(1) c = 18.221(3) Å, β = 113.97(1)°, V = 2063(1) Å3 and Z = 4. The six strongest reflections in the powder X-ray diffraction pattern are: [d obs in Å (I)(hkl)] 6.396(100)(110), 7.507(75)(202), 2.766(60)(316), 3.380(57)(312), 5.677(55)(111), 3.166(50)(4 0 2). The empirical formula (based on 25 anions p.f.u.) is Bi2.41N1.52Na2.41K0.48 S6.07H8.08O25. The calculated density is 3.87 g cm–3. Using single-crystal diffraction data, the structure was refined to a final R(F) = 0.051 for 3025 independent observed reflections [I > 2σ(I)]. Campostriniite is isostructural with görgeyite and belongs to the 7.CD group of the Strunz classification system. The structure contains two independent nine-fold coordinated sites, one of them located on a two-fold axis (M1) and the other one in general position (M2) essentially occupied by Bi 3+atoms and minor amounts of Na +ions, an eight-fold coordinated site fully occupied by Na +ions and another eight-fold coordinated site occupied by NH4+ and K+ ions; three independent sulfate anions in a general position and a water molecule coordinated to M1 and located on a two-fold axis are also present.
    No preview · Article · Aug 2015 · Mineralogical Magazine
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    ABSTRACT: Mambertiite, BiMo5+2.80O8(OH), is a new mineral identified in small vugs of quartz veins from Su Seinargiu, Sarroch, Cagliari, Sardinia, Italy. It occurs as pale yellow {001} tabular crystals, up to 1 mm in length and few μm thick, with adamantine lustre. Mambertiite is brittle, with a conchoidal fracture. It is associated with ferrimolybdite, muscovite, quartz, sardignaite, and wulfenite. Electron microprobe data (wt% – mean of 12 spot analyses) are: Mo2O5 59.59, Bi2O3 36.96, WO3 2.03, H2Ocalc 1.48, sum 100.06. On the basis of 9 O atoms per formula unit, the empirical formula is Bi0.99(Mo5+2.74W0.05)Σ2.79O7.97(OH)1.03. Infrared spectra showed absorption bands consistent with the occurrence of OH– groups. Mambertiite is triclinic, space group P1, with a = 5.854(2), b = 9.050(3), c = 7.637(3) Å, α = 112.85(1), β = 102.58(1), γ = 90.04(1)°, V = 362.3(2) Å3, Z = 2. The crystal structure of mambertiite was solved and refined down to R 1 = 0.050 on the basis of 2019 observed [F o > 4σ(F o)] reflections. It is composed by eight-fold coordinated Bi-centred polyhedra and five independent Mo-centred octahedra. Among the latter, two are completely occupied by molybdenum, whereas the remaining three are only partially occupied. Two kinds of (101) layers occur in mambertiite, alternating along [101]*: one is composed by Bi-centered polyhedra and the two partially occupied Mo4 and Mo5 sites, whereas the other is composed by the zigzag chains, running along c, formed by the fully occupied Mo1 and Mo2 sites, and the partially occupied Mo3 site. Mambertiite is structurally related to gelosaite, BiMo6+2O7(OH) · H2O; their relationships can be conveniently described through the OD theory. Mambertiite is the fourth known mineral with Bi and Mo as essential components. Its name honours the Italian mineral collector Marzio Mamberti (b. 1959) for his contribution to the knowledge of the Sardinian mineralogy. The mineral and its name have been approved by the IMA CNMNC (No. 2013–098).
    No preview · Article · Jun 2015 · European Journal of Mineralogy
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    ABSTRACT: We present an extended x-ray absorption fine structure study of the pyrochlore ${\mathrm{Y}}_{2}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$ (8\char21{}298 K). We find evidence, on a local scale, of a significant magnetoelastic coupling at the N\'eel temperature ${T}_{\mathrm{N}}\ensuremath{\sim}77\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ pointed out by a huge Debye-Waller ${\ensuremath{\sigma}}^{2}$ factor deviation from a correlated temperature dependent Debye-like local order behavior plus a temperature independent static contribution. Moreover, we notice the occurrence of a potential local order-disorder structural phase transition at ${T}^{*}=150$ K. This anomalous behavior is consistent with the pyrochlore's predisposition towards structural disorder and with a strong spin-phonon correlation. Remarkably the low-temperature order competes with the tendency of magnetic frustration to induce a less symmetric local structure.
    Full-text · Article · Jun 2015 · Physical Review B
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    ABSTRACT: The tetrahedral S-coordinated complex [Zn(MeImHS)4](ClO4)2, synthesised from the reaction of [Zn(ClO4)2] with methimazole (1-methyl-3H-imidazole-2-thione, MeImHS), reacts with triethylamine to yield the homoleptic complex [Zn(MeImS)2] (MeImS = anion methimazole). ESI-MS and MAS 13C-NMR experiments supported MeImS acting as (N,S)-chelating ligand. The DFT-optimised structure of [Zn(MeImS)2] is also reported and the main bond lengths compared to those of related Zn-methimazole complexes. The complex [Zn(MeImS)2] reacting under mild conditions with methyl iodide separates the novel complex [Zn(MeImSMe)2I2] (MeImSMe = S-methylmethimazole). X-ray diffraction analysis of the complex shows a ZnI2N2 core, with the methyl thioethers uncoordinated to zinc. Conversely, the reaction of [Zn(MeImS)2] with hydroiodic acid led to the formation of the complex [Zn(MeImHS)2I2] having a ZnI2S2 core with the neutral methimazole units S-coordinating the metal centre. The Zn-coordinated methimazole can markedly modify the coordination environment when changing from its thione to thionate form, and vice versa. The study of the interaction of the drug methimazole with the complex [Zn(MeIm)4]2+ (MeIm = 1-methylimidazole) — as a model for Zn-enzymes containing a N4 donor set from histidine residues — shows that methimazole displaces only one of the coordinated MeIm molecules; the formation constant of the mixed-complex [Zn(MeIm)3(MeImHS)]2+ was determined.
    Full-text · Article · Apr 2015 · Dalton Transactions
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    Campostrini I. · Demartin F. · Russo M.

    Full-text · Conference Paper · Sep 2014
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    Russo M. · Campostrini I. · Demartin F.

    Full-text · Conference Paper · Sep 2014
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    ABSTRACT: The cytotoxic properties of copper(II) complexes with 1,10-phenanthroline (phen) can be modified by substitution in the phen backbone. For this purpose, Cu(II) complexes with phen, 1,10-phenanthrolin-5,6-dione (phendione) and 1,10-phenanthrolin-5,6-diol (phendiol) have been synthesised and characterised. The crystal structure of [Cu(phendione)2(OH2)(OClO3)](ClO4) is discussed. The complex formation equilibria between Cu(II) and phen or phendione were studied by potentiometric measurements at 25 and 37°C in 0.1M ionic strength (NaCl). The antitumour activity of the compounds has been tested in vitro against a panel of tumour (DU-145, HEP-G2, SK-MES-1, CCRF-CEM, CCRF-SB) and normal (CRL-7065) human cell lines. The studied compounds generally present an antiproliferative effect greater than that of cisplatin. The phen and phendione ligands present a similar antiproliferative effect against all the tested cells. Phendiol presents an antiproliferative effect 1.3 to 18 times greater than that of phen or phendione for leukemic, lung, prostatic and fibroblast cells, while it presents less activity towards hepatic cells. Complexes with two ligands are more cytotoxic towards all the tested cell lines than complexes with one ligand and are generally more cytotoxic than the ligand alone. Complexes [Cu(phendiol)2(OH2)](ClO4)2 and [Cu(phendione)2(OH2)(OClO3)](ClO4) appear to be the most active compounds for the treatment of SK-MES-1 and HEP-G2 cells, respectively, being at least 18 times more cytotoxic than cisplatin. The studied Cu(II) complexes are characterised by a strong DNA affinity and were found to interact with DNA mainly by groove binding or electrostatic interactions. The complexes appear to act on cells with a mechanism different from that of cisplatin.
    Full-text · Article · Sep 2014 · Journal of Inorganic Biochemistry
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    Full-text · Article · Sep 2014
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    ABSTRACT: In the context of the development of new electron mediators for Dye-Sensitized Solar Cells that could efficiently substitute the more common I3-/I- redox couple, we have prepared a series of Cu(I)- phenanthroline complexes through an easy synthetic route. The novel [Cu(2-mesityl-4,7-dimethyl-1,10-phenanthroline)2]PF6 (3) is of particular interest because the presence of the bulky mesityl groups protects as a kiss lock the Cu center, leading to superior dye regeneration kinetics with respect to simpler phenanthroline based Cu(I) complexes and to a lower dark current with respect the I3-/I- . The exploitation of a dual-component electrolyte constituted by (3) and a Fe(II) co-mediator, in combination with the [Ru(4,4'-dicarboxy-2,2'-bipyridine)2(4,4'-dinonyl-2,2'-bipyridine)](PF6)2 sensitizer, allowed to increase the performance of the cell reaching Jsc values of 4.0 mA cm-2, comparable to that recorded with I3-/I- (3.8 mA cm-2).
    No preview · Article · Jul 2014 · ACS Applied Materials & Interfaces
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    Full-text · Conference Paper · Jun 2014
  • Italo Campostrini · Francesco Demartin · MAssimo Russo
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    ABSTRACT: Nell’ambito della collaborazione tra il Dipartimento di Chimica dell’Università degli Studi di Milano e la Sezione di Napoli dell’Istituto Nazionale di Geofisica e Vulcanologia (Osservatorio Vesuviano) è stato intrapreso un progetto di ricerca riguardante lo studio di minerali di origine fumarolica formatisi nel corso delle passate eruzioni del Vesuvio. In particolare sono stati presi in esame sia campioni storici, appartenenti alla collezione mineralogica dell’Osservatorio Vesuviano, sia campioni raccolti nel corso di campagne di ricerca svolte negli ultimi anni sulle fumarole dell’eruzione del 1944. Oltre a specie già note sono stati identificati alcuni minerali mai segnalati in precedenza al Vesuvio ed anche alcune specie nuove. Tra i minerali identificati sui campioni storici sono di particolare interesse la kröhnkite, la leightonite e la thermessaite. In particolare per quest’ultima si tratta del secondo ritrovamento mondiale dopo quello della località-tipo (Cratere della Fossa all’Isola di Vulcano). È stato inoltre rinvenuto un nuovo fluoruro idrato di calcio ed alluminio di formula Ca3Al2F12•5H2O, che sta per essere sottoposto alla CNMMN dell’IMA per l’approvazione come nuovo minerale. Sui campioni dell’eruzione del 1944 abbiamo potuto identificare oltre alle fasi già note in precedenza anche coulsellite, phoenicochroite, sellaite, caledonite e matlockite. Sugli stessi campioni è inoltre presente anche la parascandolaite, KMgF3, recentemente approvata (IMA-2013-092).
    No preview · Conference Paper · Jun 2014
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    Campostrini I. · Demartin F. · Russo M.

    Full-text · Conference Paper · Jun 2014
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    Campostrini I. · Demartin F. · Russo M.

    Full-text · Conference Paper · Jun 2014
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    Campostrini I. · Demartin F. · Russo M.

    Full-text · Conference Paper · Jun 2014
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    Francesco Demartin · Italo Campostrini · Carlo Castellano · Massimo Russo
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    ABSTRACT: The new mineral parascandolaite, isotypic to cubic perovskites, space group Pm \(\overline{3}\) m (no. 221) is the natural analog of the synthetic fluoride KMgF3 and is related to neighborite, NaMgF3. It was found as a volcanic sublimate at Vesuvius volcano on 1944 eruption lava scoria, associated with opal, cerussite, mimetite, phoenicochroite and coulsellite. It occurs as transparent colorless to white cubic crystals up to 0.5 mm in length with vitreous luster. The density measured by flotation in a diiodomethane–toluene mixture is 3.11(1) g/cm3; that calculated from the empirical formula and single-crystal X-ray data is 3.123 g/cm3. The mineral is isotropic with n = 1.395(5) (580 nm). The six strongest reflections in the X-ray powder diffraction pattern are: [d obs in Å(I)(h k l)] 2.001(100)(2 0 0), 2.831(83)(1 1 0), 2.311(78)(1 1 1), 1.415(56)(2 2 0), 1.633(35)(2 1 1) and 1.206(22)(3 1 1). The unit-cell parameter is a = 4.0032(9) Å. The structure was refined to a final R(F) = 0.0149 for 35 independent observed reflections [I > 2σ(I)]. The mineral is named after the Italian mineralogist Antonio Parascandola (1902–1977).
    Full-text · Article · Mar 2014 · Physics and Chemistry of Minerals
  • F. Demartin · C. Castellano · I. Campostrini
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    ABSTRACT: The new mineral therasiaite, ideally (NH4)3KNa2Fe2+Fe3+(SO4)3Cl5, was found in a medium-temperature (∼250°C) intracrater active fumarole at La Fossa crater, Vulcano, Aeolian Islands, Sicily, Italy. It occurs on a pyroclastic breccia as brown to dark brown equant to short prismatic crystals up to 0.1 mm in length, in association with salammoniac, kremersite and adranosite. The mineral is monoclinic, space group: Cc (no. 9) with a = 18.284(4), b = 12.073(2), c = 9.535(2) Å, b = 108.10(3)°, V = 2000.6(7) Å3 and Z = 4. The six strongest reflections in the X-ray powder diffraction pattern are: [d obs in Å (I)(h k l)] 2.812(100)(223), 2.664(77)(513), 3.297(28)(331), 3.208(14)(512), 3.008(12)(040), 2.942(11)(331). The empirical formula (based on 17 anions per formula unit (p.f.u.)) is (NH4)2.68K1.32Na2.04Fe1.76Al0.12Mn0.12S2.98O11.95Cl5.05. The measured density is 2.41(1) g cm–3, d calc = 2.395 g cm–3. The mineral is biaxial (–) with α = 1.585(3) β = 1.615(3) and γ = 1.630(3) (white light). Using single-crystal diffraction data, the structure was refined to a final R(F) = 0.0240 for 5574 independent observed reflections [I > 2σ(I)]. The structure of therasiaite displays a novel topology and contains two independent, distorted octahedral Fe sites, with the Fe atoms in oxidation state 3+ and 2+, respectively, each surrounded by three Cl atoms and three oxygens of the sulfate ions. The Fe octahedra and the three independent sulfate anions are connected to form chains running along [001]. Voids between the chains are occupied by three independent ammonium ions (partially replaced by K+), one K+ and two Na+ ions. The formula resulting from the structure refinement is [(NH4)2.25K0.75]KNa2Fe2(SO4)3Cl5.
    No preview · Article · Feb 2014 · Mineralogical Magazine
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    ABSTRACT: The reactions of 1,3,8,10-tetrakis(4'-fluorophenyl)-4,5,6,7-tetrathiocino[1,2-b:3,4-b']diimidazolyl-2,9-dithione (4) and molecular diiodine afforded spoke adducts with stoichiometries 4⋅I2 and 4⋅3I2 , isolated in the compound 4⋅3I2 ⋅xCH2 Cl2 ⋅(1-x)I2 (x=0.70), and characterized by single-crystal XRD and FT-Raman spectroscopy. The nature of the reaction products was investigated under the prism of theoretical calculations carried out at the DFT level. The structural data, FT-Raman spectroscopy, and quantum mechanical calculations agree in indicating that the introduction of fluorophenyl substituents results in a lowering of the Lewis basicity of this class of bis(thiocarbonyl) donors compared with alkyl-substituted tetrathiocino donors and fluorine allows for extended interactions that are responsible for solid-state crystal packing.
    No preview · Article · Sep 2013 · Chemistry - An Asian Journal
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    ABSTRACT: The trinuclear [Ln(NO3)3(CuL)2] complexes (Ln = La, Ce, Sm, Eu and Er, L = N,N'-1,3-propylen-bis(salicylideniminato) have been investigated by a combination of HLS and EFISH techniques to evaluate both the dipolar and octupolar contributions to their significant quadratic hyperpolarizability and to confirm that f electrons may tune their second-order NLO response. In the complexes investigated, the major contribution to the total quadratic hyperpolarizability is largely controlled by the octupolar contribution, but the values of both βEFISH and ∥β(J=1)∥, that is the dipolar part, are significantly influenced by the number of f electrons, confirming that the unexpected polarizable character of f electrons may be the origin of such fascinating evidence.
    Full-text · Article · Jun 2013 · Inorganic Chemistry
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    ABSTRACT: A chemodosimeter Ph2P(S)NP(–S–CH2–anthracene)Ph2 (L1), featuring the methylanthracenyl moiety covalently linked to one of the two S atoms of an S,S′-tetraphenyldithioimidodiphosphinate (L) unit exhibited good selectivity and sensitivity for Hg2+ in an aqueous environment. The chemical reaction involved differs from those reported in the literature for other Hg2+ chemodosimeters: the binding of Hg2+ induces the cleavage of the PS–CH2 bond to form the stable neutral complex [HgL2] and an emissive anthracenyl derivative. The X-ray crystal structure of L1 is reported (CCDC number 919620).
    No preview · Article · Jun 2013 · RSC Advances

Publication Stats

5k Citations
886.92 Total Impact Points

Institutions

  • 1981-2015
    • University of Milan
      • • Department of Chemistry, Biochemistry and Biotechnologies for Medical Sciences
      • • Department of Inorganic, Organometallic and Analytical Chemistry "Lamberto Malatesta" CIMA
      • • Department of Organic and Industrial Chemistry
      • • Istituto di Chimica Farmaceutica e Tossicologica
      • • Istituto di Patologia Generale
      Milano, Lombardy, Italy
  • 2010
    • Università degli studi di Cagliari
      • Department of Chemical and Geological Science
      Cagliari, Sardinia, Italy
  • 2008
    • Royal Ontario Museum
      Toronto, Ontario, Canada
  • 1991-2005
    • Politecnico di Milano
      Milano, Lombardy, Italy
  • 1997-2003
    • Università degli Studi del Sannio
      Benevento, Campania, Italy
  • 2000
    • Università degli Studi della Basilicata
      Potenza, Basilicate, Italy
  • 1996
    • Università degli Studi di Siena
      Siena, Tuscany, Italy
    • University of Nottingham
      • School of Chemistry
      Nottigham, England, United Kingdom
  • 1990
    • INO - Istituto Nazionale di Ottica
      Florens, Tuscany, Italy