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Gaetano Verani - One of the best experts on this subject based on the ideXlab platform.

  • A new assembly of Diiodine molecules at the triphenylphosphine sulfide template
    Journal of the Chemical Society Dalton Transactions, 1999
    Co-Authors: Massimiliano Arca, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Francesco Demartin, Alessandra Garau, Gaetano Verani
    Abstract:

    The new I2 adduct TPPS·3I2 (TPPS = triphenylphosphine sulfide) has been synthesized and characterised by X-ray diffraction on a single crystal. It consists of a TPPS·I2 1:1 molecular adduct interacting with two further Diiodine molecules in a "head to tail" sequence to give an overall TPPS·I2 ⋯ I2 ⋯ I2 arrangement in the asymmetric unit. Considering the I ⋯ I interactions below 3.6 Å, five of the six iodine atoms of the asymmetric unit are arranged in infinite polycyclic ribbons. The iodine atoms, to which the TPPS molecules are connected, are almost perpendicular appendages on opposite sides of each ribbon. Weaker interactions between the ribbons give rise to unprecedented continuous stepped layers of Diiodine molecules anchored to TPPS donor units. The structural features of TPPS·3I2 are discussed in comparison with those of the previously reported 2TPPS·3I2, TPPS-I2, TPPS·IBr and TPPS·ICl, and its FT-Raman spectrum compared with those of 2TPPS·3I2 and TPPS·I2. A re-examination of the equilibrium reaction between TPPS and I2 by 31P NMR confirms the formation of the 1:1 adduct in CH2Cl2 solution and gives a formation constant value of 137 ± 11 dm3 mol-1

  • Reaction of N,N′-dimethylimidazolidine-2-selone (L) with I2. Crystal structure of the mixed-valence (L·I2)(L2)2+·2I3 − compound
    Inorganica Chimica Acta, 1997
    Co-Authors: Francesco Demartin, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Gaetano Verani
    Abstract:

    From the reaction of N,N'-dimethylimidazolidine-2-selone (L) with I-2 the mixed-valence (L . I-2)(L(2))(2+). 2I(3)(-) compound has been prepared. (L . I-2)(L(2))(2+). 2I(3)(-) consists of a neutral adduct between L and a Diiodine molecule and a triiodide salt, whose dication is formed by two L molecules joined through an Se-Se bond. This is the first example of a dication bearing the -Se-Se- bridge obtained by direct oxidation of a selenic compound with Diiodine. FT-IR and FT-Raman spectra agree well with the structural features. Crystals of (L . I-2)(L(2))(2+). 2I(3)(-) are triclinic, space group , Z = 2, with unit cell dimensions a = 8.465(2), b = 10.233(3), c = 21.798(8) Angstrom, alpha = 95.81(3), beta = 90.53(2), gamma = 103.18(2)degrees, R = 0.027

  • Reactivity of 1,3,5-Trithiacyclohexane and 1,3,5-Triselenacyclohexane towards molecular Diiodine. Crystal structures of the Diiodine adducts
    Polyhedron, 1997
    Co-Authors: Massimiliano Arca, Franco Cristiani, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Gaetano Verani, Alessandra Garau, Francesco Demartin
    Abstract:

    Abstract The reactions between I2 and the donors (D) 1,3,5-trithiacyclohexane (1) and 1,3,5-triselenacyclohexane (2), in methylene chloride and hot benzene respectively (1:1 I2:D molar ratio) give the solid adducts 1·I2 (I) and 2 · I2 (II) whose structures have been solved by X-ray diffraction. The use of an excess of Diiodine up to the molar ratio 2:1 always gives II from 2, and 1·2I2 (III) from 1. Compound I consists of polymeric chains in which each Diiodine bridges between different 1 molecules, while II consists of discrete molecular units. The Raman ν(II) frequency and II bond distance in I fits well with the previously found linear correlation. This correlation suggests two different II bond distances for III. The comparison of the FTIR and FT-Raman spectra for II is consistent with the three-body model for SeII. The association constant between 1 and I2 in methylene chloride has been also studied both by UV-visible and 13C NMR spectroscopy, giving K values at 21°C in good agreement.

  • charge transfer complexes of benzoxazole 2 3h thione and benzoxazole 2 3h selone with Diiodine x ray crystal structure of benzoxazole 2 3h thione bis Diiodine
    Polyhedron, 1995
    Co-Authors: Franco Cristiani, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Gaetano Verani, Francesco Demartin
    Abstract:

    Abstract Solids of stoichiometry 1·I2 (C7H5I2NOS; I), 1·2I2 (C7H5I4NOS; II), 2·I2 (C7H5I2NOSe; III) and 2·2I2 (C7H5I4NOSe; IV) have been obtained by reacting respectively benzoxazole-2(3H)-thione (1) and benzoxazole-2(3H)-selone (2) with molecular Diiodine in a 1:1 or 1:2 molar ratio in CH2Cl2 solution. Crystals suitable for X-ray structure determination have been obtained only for II and contain units formed by one Diiodine molecule bonded almost linearly [178.44(4)°] to the thionic sulphur atom of 1 and another Diiodine molecule weakly interacting with the former. The FT-Raman spectrum in the characteristics v(I-I) region shows two bands for compound II at 176 and 159 cm−1, in accordance with the presence of two differently perturbed Diiodine molecules [ I (1)– I (2) = 2.769(1) A , I (3)– I (4) = 2.729(1) A ] . The FT-IR and FT-Raman spectra of compounds I, III and IV are discussed in comparison with the spectrum of II and with those reported for similar charge transfer complexes.

  • Charge transfer complexes of benzoxazole-2(3H)-thione and benzoxazole-2(3H)-selone with Diiodine: X-ray crystal structure of benzoxazole-2(3H)-thione bis(Diiodine)
    Polyhedron, 1995
    Co-Authors: Franco Cristiani, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Gaetano Verani, Francesco Demartin
    Abstract:

    Solids of stoichiometry 1 . I-2 (C7H5I2NOS; I), 1 . 2I(2) (C7H5I4NOS; II), 2 . I-2 (C7H5I2NOSe; III) and 2 . 2I(2) (C7H5I4NOSe; IV) have been obtained by reacting respectively benzoxazole-2(3H)-thione (1) and benzoxazole-2(3H)-selone (2) with molecular Diiodine in a 1:1 or 1:2 molar ratio in CH2Cl2 solution. Crystals suitable for X-ray structure determination have been obtained only for II and contain units formed by one Diiodine molecule bonded almost linearly [178.44(4)degrees] to the thionic sulphur atom of 1 and another Diiodine molecule weakly interacting with the former. The FT-Raman spectrum in the characteristic nu(I-I) region shows two bands for compound II at 176 and 159 cm(-1), in accordance with the presence of two differently perturbed Diiodine molecules [I(1)-I(2) = 2.769(1) Angstrom, I(3)-I(4) = 2.729(1)Angstrom]. The FT-IR and FT-Raman spectra of compounds I, III and IV are discussed in comparison with the spectrum of II and with those reported for similar charge transfer complexes

Francesco A. Devillanova - One of the best experts on this subject based on the ideXlab platform.

  • Structural and DFT studies of dibromine and Diiodine adducts of a sulfur-rich thiocarbonyl donor
    European Journal of Inorganic Chemistry, 2012
    Co-Authors: Annalisa Mancini, Francesco A. Devillanova, Michael B Hursthouse, Mark E Light, Luca Pala, M. Carla Aragoni, Massimiliano Arca, Peter J. Skabara, Neil Bricklebank
    Abstract:

    4,5-Bis(benzoylthio)-1,3-dithiole-2-thione (1) forms molecular adducts with dibromine (2) and Diiodine (3), which display a range of complementary primary X-X and S-X and secondary S center dot X and X center dot X bonding interactions. Compounds 2 and 3 were characterised by X-ray diffraction analysis and FT-Raman spectroscopy. Compound 2, which is derived from the additive dibromine oxidation of 1, features a near linear BrSBr moiety that is coplanar with the dithiole-2-thione heterocycle. The SBr bonds in 2 are asymmetric; the asymmetry arises mainly through a combination of intramolecular S center dot Br bonds between the Br atoms and the thioether S atoms of the donor, and an intermolecular S center dot Br contact between one of the bromine atoms and the hypervalent S atom of an adjacent molecule. DFT calculations carried out on 2 with different functionals agree and show that the geometry featuring the SBr2 moiety coplanar with the heterocycle is more stable by about 9 kcal mol1 than that with the SBr2 unit perpendicular to the plane of the heterocycle. DFT calculations indicate that the formation of 2 can be explained based on the charge distribution on the hypothetical cationic intermediate [1-Br]+. Diiodine complex 3 is a molecular charge-transfer species, with an almost linear S-I-I moiety. The unit cell contains two molecules of donor 1, related by a centre of inversion, which form a dimer pair held together by two intermolecular S center dot S and two S center dot O contacts. The packing of the dimers generates various cavities that are able to accommodate I2 molecules as guests, in one case the guest Diiodine molecule bonds with the sulfur atoms of the benzoylthio-groups and acts as a bridge between adjacent dimers, in another the Diiodine is disordered along the channel-like cavity. The terminal iodine atom of each SII fragment interacts with two additional I2 molecules leading to infinite chains in the [011] direction

  • Square-pyramidal bonding of I2 molecules at the I− nodes of a polyiodide infinite pseudo-cubic 3D-network
    CrystEngComm, 2004
    Co-Authors: M. Carla Aragoni, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Michael B Hursthouse, Massimiliano Arca, Susanne L. Huth, Annalisa Mancini
    Abstract:

    The reaction of di-[2]-pyridyl-disulfide (L) with Diiodine in molar ratios ranging between 1 : 0.5 and 1 : 5 afforded [(HL+)(I−)·5/2I2] as the only product, containing the first example of a self-assembled infinite polyiodide pseudo-cubic 3D-network featuring distorted square pyramidal I−·5I2 moieties at the nodes

  • A new assembly of Diiodine molecules at the triphenylphosphine sulfide template
    Journal of the Chemical Society Dalton Transactions, 1999
    Co-Authors: Massimiliano Arca, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Francesco Demartin, Alessandra Garau, Gaetano Verani
    Abstract:

    The new I2 adduct TPPS·3I2 (TPPS = triphenylphosphine sulfide) has been synthesized and characterised by X-ray diffraction on a single crystal. It consists of a TPPS·I2 1:1 molecular adduct interacting with two further Diiodine molecules in a "head to tail" sequence to give an overall TPPS·I2 ⋯ I2 ⋯ I2 arrangement in the asymmetric unit. Considering the I ⋯ I interactions below 3.6 Å, five of the six iodine atoms of the asymmetric unit are arranged in infinite polycyclic ribbons. The iodine atoms, to which the TPPS molecules are connected, are almost perpendicular appendages on opposite sides of each ribbon. Weaker interactions between the ribbons give rise to unprecedented continuous stepped layers of Diiodine molecules anchored to TPPS donor units. The structural features of TPPS·3I2 are discussed in comparison with those of the previously reported 2TPPS·3I2, TPPS-I2, TPPS·IBr and TPPS·ICl, and its FT-Raman spectrum compared with those of 2TPPS·3I2 and TPPS·I2. A re-examination of the equilibrium reaction between TPPS and I2 by 31P NMR confirms the formation of the 1:1 adduct in CH2Cl2 solution and gives a formation constant value of 137 ± 11 dm3 mol-1

  • Synthesis, X-ray and spectroscopic characterization of obtained throught the one-step reaction of mbit·2I2 with tin metal powder (mbit = 1,1′-bis(3-methyl-4-imidazoline-2-thione)methane)
    Inorganica Chimica Acta, 1998
    Co-Authors: Francesco Bigoli, Francesco A. Devillanova, Vito Lippolis, Paola Deplano, Maria Angela Pellinghelli, Maria Laura Mercuri, Emanuele F. Trogu
    Abstract:

    Abstract The reaction of the adduct mbit·2I2 (mbit = 1,1′-bis(3-methyl-4-imidazoline-2-thione)methane) with tin metal powder produces Sn(mbit)2I9, in mild conditions. An X-ray diffraction study on a crystal showed that the compound consists of a cation [SnI2(mbot)2]2+ having two I2 as counterions, interacting with two disordered Diiodine molecules. In the cation, the metal atom lying on a symmetry centre exhibits a slightly distorted octahedral coordination with the two iodides at the apices in trans position, and with the two mbit molecules acting as bidentate chelating ligands through the sulfur atoms and forming an eight-membered ring, the tin metal atom included. The counterions I1 are slightly bent (I(2)–I(3)–I(4) 176.0(1)) and so asymmetric (I(2)–I(3) 2.841(6) I(3)−I(4) 3.016(5) A) that they can be better described as I ·I2 adducts. The presence of the two independent, centrosymmetric and disordered Diiodine molecules as guests in the channel running parallel to [III] brings about I82 units of the type I2·I✓I2✓I·I2, here two triiodide ions realted by a sym centre are linked only for one third to I(5)–I(510), that is one of the two disordered guest I2 molecules (I(4)✓I(5) 3.22(I) A). Two I82 units related by a symmetry centre are held together through a non-negligible interaction (I(4)✓I(6) 3.55(1) A) involving the other disordered Diiodine molecule (I(6)–I(6m)) giving rise to an octadecaioddide. Crystallographic data for C18H24N8S4I90Sn are as follows: the crystal is trigonal. M = 1783.77 space group R3, Z = 3, V = 3146(4) A ′, a = 18.100(6) A , α = 115.55(2)°, R = 0.0584 . In accordance with a description of the counterions as a sequence of the type I2·I✓I2✓I·I2. FT-Raman spectra do not show the peaks generally found in conventional triiodides, but those related to perturbed Diiodine molecules.

  • Reaction of N,N′-dimethylimidazolidine-2-selone (L) with I2. Crystal structure of the mixed-valence (L·I2)(L2)2+·2I3 − compound
    Inorganica Chimica Acta, 1997
    Co-Authors: Francesco Demartin, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Gaetano Verani
    Abstract:

    From the reaction of N,N'-dimethylimidazolidine-2-selone (L) with I-2 the mixed-valence (L . I-2)(L(2))(2+). 2I(3)(-) compound has been prepared. (L . I-2)(L(2))(2+). 2I(3)(-) consists of a neutral adduct between L and a Diiodine molecule and a triiodide salt, whose dication is formed by two L molecules joined through an Se-Se bond. This is the first example of a dication bearing the -Se-Se- bridge obtained by direct oxidation of a selenic compound with Diiodine. FT-IR and FT-Raman spectra agree well with the structural features. Crystals of (L . I-2)(L(2))(2+). 2I(3)(-) are triclinic, space group , Z = 2, with unit cell dimensions a = 8.465(2), b = 10.233(3), c = 21.798(8) Angstrom, alpha = 95.81(3), beta = 90.53(2), gamma = 103.18(2)degrees, R = 0.027

Vito Lippolis - One of the best experts on this subject based on the ideXlab platform.

  • Square-pyramidal bonding of I2 molecules at the I− nodes of a polyiodide infinite pseudo-cubic 3D-network
    CrystEngComm, 2004
    Co-Authors: M. Carla Aragoni, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Michael B Hursthouse, Massimiliano Arca, Susanne L. Huth, Annalisa Mancini
    Abstract:

    The reaction of di-[2]-pyridyl-disulfide (L) with Diiodine in molar ratios ranging between 1 : 0.5 and 1 : 5 afforded [(HL+)(I−)·5/2I2] as the only product, containing the first example of a self-assembled infinite polyiodide pseudo-cubic 3D-network featuring distorted square pyramidal I−·5I2 moieties at the nodes

  • A new assembly of Diiodine molecules at the triphenylphosphine sulfide template
    Journal of the Chemical Society Dalton Transactions, 1999
    Co-Authors: Massimiliano Arca, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Francesco Demartin, Alessandra Garau, Gaetano Verani
    Abstract:

    The new I2 adduct TPPS·3I2 (TPPS = triphenylphosphine sulfide) has been synthesized and characterised by X-ray diffraction on a single crystal. It consists of a TPPS·I2 1:1 molecular adduct interacting with two further Diiodine molecules in a "head to tail" sequence to give an overall TPPS·I2 ⋯ I2 ⋯ I2 arrangement in the asymmetric unit. Considering the I ⋯ I interactions below 3.6 Å, five of the six iodine atoms of the asymmetric unit are arranged in infinite polycyclic ribbons. The iodine atoms, to which the TPPS molecules are connected, are almost perpendicular appendages on opposite sides of each ribbon. Weaker interactions between the ribbons give rise to unprecedented continuous stepped layers of Diiodine molecules anchored to TPPS donor units. The structural features of TPPS·3I2 are discussed in comparison with those of the previously reported 2TPPS·3I2, TPPS-I2, TPPS·IBr and TPPS·ICl, and its FT-Raman spectrum compared with those of 2TPPS·3I2 and TPPS·I2. A re-examination of the equilibrium reaction between TPPS and I2 by 31P NMR confirms the formation of the 1:1 adduct in CH2Cl2 solution and gives a formation constant value of 137 ± 11 dm3 mol-1

  • trans-dichloro([16]aneS4)rhodium(III) pentaiodide Diiodine
    Acta Crystallographica Section C Crystal Structure Communications, 1998
    Co-Authors: Alexander J. Blake, Vito Lippolis, Martin Schröder
    Abstract:

    In the title compound, trans-dichloro(1,5,9,13-tetrathiacyclohexadecane-κ 4 S)rhodium(III) pentaiodide Diiodine, [RhCl 2 (C 12 H 24 S 4 )](I 5 ).I 2 the complex cations are embedded in a three-dimensional polyiodide matrix composed of cages of I 5 - ions and I 2 molecules interacting via I...I contacts which range from 3.336 (2) to 4.133 (2) A.

  • Synthesis, X-ray and spectroscopic characterization of obtained throught the one-step reaction of mbit·2I2 with tin metal powder (mbit = 1,1′-bis(3-methyl-4-imidazoline-2-thione)methane)
    Inorganica Chimica Acta, 1998
    Co-Authors: Francesco Bigoli, Francesco A. Devillanova, Vito Lippolis, Paola Deplano, Maria Angela Pellinghelli, Maria Laura Mercuri, Emanuele F. Trogu
    Abstract:

    Abstract The reaction of the adduct mbit·2I2 (mbit = 1,1′-bis(3-methyl-4-imidazoline-2-thione)methane) with tin metal powder produces Sn(mbit)2I9, in mild conditions. An X-ray diffraction study on a crystal showed that the compound consists of a cation [SnI2(mbot)2]2+ having two I2 as counterions, interacting with two disordered Diiodine molecules. In the cation, the metal atom lying on a symmetry centre exhibits a slightly distorted octahedral coordination with the two iodides at the apices in trans position, and with the two mbit molecules acting as bidentate chelating ligands through the sulfur atoms and forming an eight-membered ring, the tin metal atom included. The counterions I1 are slightly bent (I(2)–I(3)–I(4) 176.0(1)) and so asymmetric (I(2)–I(3) 2.841(6) I(3)−I(4) 3.016(5) A) that they can be better described as I ·I2 adducts. The presence of the two independent, centrosymmetric and disordered Diiodine molecules as guests in the channel running parallel to [III] brings about I82 units of the type I2·I✓I2✓I·I2, here two triiodide ions realted by a sym centre are linked only for one third to I(5)–I(510), that is one of the two disordered guest I2 molecules (I(4)✓I(5) 3.22(I) A). Two I82 units related by a symmetry centre are held together through a non-negligible interaction (I(4)✓I(6) 3.55(1) A) involving the other disordered Diiodine molecule (I(6)–I(6m)) giving rise to an octadecaioddide. Crystallographic data for C18H24N8S4I90Sn are as follows: the crystal is trigonal. M = 1783.77 space group R3, Z = 3, V = 3146(4) A ′, a = 18.100(6) A , α = 115.55(2)°, R = 0.0584 . In accordance with a description of the counterions as a sequence of the type I2·I✓I2✓I·I2. FT-Raman spectra do not show the peaks generally found in conventional triiodides, but those related to perturbed Diiodine molecules.

  • 1,4,8,11‐Tetrakis(Diiodine)‐1,4,8,11‐tetrathiacyclotetradecane
    Acta Crystallographica Section C Crystal Structure Communications, 1997
    Co-Authors: Alexander J. Blake, Vito Lippolis, Martin Schröder
    Abstract:

    The title compound, C 10 H 20 S 4 .4I 2 , [14]aneS 4 .4I 2 , possesses crystallographically imposed inversion symmetry and has all four S donor atoms coordinated to Diiodine molecules. The principal geometric parameters for the two inequivalent pairs of interactions are S-I 2.803 (2) and 2.880(2)A, I-I 2.7894 (8) and 2.7571(10)A, and S-I-I 177.71(5) and 172.50(4)°. Molecules are linked by S...I and I...I intermolecular contacts to form an infinite three-dimensional lattice.

Francesco Isaia - One of the best experts on this subject based on the ideXlab platform.

  • Square-pyramidal bonding of I2 molecules at the I− nodes of a polyiodide infinite pseudo-cubic 3D-network
    CrystEngComm, 2004
    Co-Authors: M. Carla Aragoni, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Michael B Hursthouse, Massimiliano Arca, Susanne L. Huth, Annalisa Mancini
    Abstract:

    The reaction of di-[2]-pyridyl-disulfide (L) with Diiodine in molar ratios ranging between 1 : 0.5 and 1 : 5 afforded [(HL+)(I−)·5/2I2] as the only product, containing the first example of a self-assembled infinite polyiodide pseudo-cubic 3D-network featuring distorted square pyramidal I−·5I2 moieties at the nodes

  • A new assembly of Diiodine molecules at the triphenylphosphine sulfide template
    Journal of the Chemical Society Dalton Transactions, 1999
    Co-Authors: Massimiliano Arca, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Francesco Demartin, Alessandra Garau, Gaetano Verani
    Abstract:

    The new I2 adduct TPPS·3I2 (TPPS = triphenylphosphine sulfide) has been synthesized and characterised by X-ray diffraction on a single crystal. It consists of a TPPS·I2 1:1 molecular adduct interacting with two further Diiodine molecules in a "head to tail" sequence to give an overall TPPS·I2 ⋯ I2 ⋯ I2 arrangement in the asymmetric unit. Considering the I ⋯ I interactions below 3.6 Å, five of the six iodine atoms of the asymmetric unit are arranged in infinite polycyclic ribbons. The iodine atoms, to which the TPPS molecules are connected, are almost perpendicular appendages on opposite sides of each ribbon. Weaker interactions between the ribbons give rise to unprecedented continuous stepped layers of Diiodine molecules anchored to TPPS donor units. The structural features of TPPS·3I2 are discussed in comparison with those of the previously reported 2TPPS·3I2, TPPS-I2, TPPS·IBr and TPPS·ICl, and its FT-Raman spectrum compared with those of 2TPPS·3I2 and TPPS·I2. A re-examination of the equilibrium reaction between TPPS and I2 by 31P NMR confirms the formation of the 1:1 adduct in CH2Cl2 solution and gives a formation constant value of 137 ± 11 dm3 mol-1

  • Structural and solution studies of Diiodine charge-transfer complexes of thioether crowns
    Journal of the Chemical Society Dalton Transactions, 1997
    Co-Authors: Alexander J. Blake, Franco Cristiani, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Alessandra Garau, Liam M. Gilby, Robert O. Gould, Simon Parsons, Christian Radek
    Abstract:

    The charge-transfer complexes 2[9]aneS 3 ·4I 2 ([9]aneS 3 = 1,4,7-trithiacyclononane), [12]aneS 4 ·I 2 ([12]aneS 4 = 1,4,7,10-tetrathiacyclododecane), [14]aneS 4 ·I 2 , [14]aneS 4 ·2I 2 ([14]aneS 4 = 1,4,8,11-tetrathiacyclotetradecane), [16]aneS 4 ·I 2 and [16]aneS 4 ·4I 2 ([16]aneS 4 = 1,5,9,13-tetrathiacyclohexadecane) have been prepared by slow evaporation of solutions containing I 2 and the appropriate thioether macrocycle in CH 2 Cl 2 . The structure of 2[9]aneS 3 ·4I 2 shows two independent macrocycles in the asymmetric unit which are linked by a Diiodine bridge. Asymmetric units are linked by I · · · I and S · · · I interactions to form an extended array of linked macrocycles. The single-crystal structure of [12]aneS 4 ·I 2 features an infinite chain structure formed by alternating [12]aneS 4 and I 2 molecules. The structure contains both symmetric and asymmetric Diiodine bridges. Although the 1∶1 adduct [14]aneS 4 ·I 2 can also be described as a one-dimensional infinite chain structure with asymmetric Diiodine bridging, the structure is better visualised as alternating layers of macrocycle and iodine spanned by short contacts of 3.335(4) A. The adduct [14]aneS 4 ·2I 2 shows two independent macrocycles each co-ordinated to two I 2 molecules. The charge-transfer network consists of chains of molecules with alternating orientations. The single-crystal structure of a third 1∶1 adduct [16]aneS 4 ·I 2 contains only symmetrical Diiodine bridges between neighbouring macrocycles leading to an infinite chain structure. The compound [16]aneS 4 ·4I 2 is the first example of a tetradentate macrocycle which incorporates I 2 bound to all four S atoms. The single-crystal structure shows four terminal I 2 molecules co-ordinated to the four S donors of the macrocycle. Molecules are linked into interwoven sheets by I · · · I interactions of 3.639(2) A. The formation enthalpies (ΔH) and constants (K) of 1∶1 adducts obtained by treating various thioether macrocycles with I 2 in CH 2 Cl 2 have been determined by electronic spectroscopy. The Fourier-transform Raman spectra for all the charge-transfer adducts have been recorded in CH 2 Cl 2 solutions at different concentrations. The Raman frequencies of the ν(I–I) vibrations show good correlation with the measured formation enthalpies ΔH.

  • Reaction of N,N′-dimethylimidazolidine-2-selone (L) with I2. Crystal structure of the mixed-valence (L·I2)(L2)2+·2I3 − compound
    Inorganica Chimica Acta, 1997
    Co-Authors: Francesco Demartin, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Gaetano Verani
    Abstract:

    From the reaction of N,N'-dimethylimidazolidine-2-selone (L) with I-2 the mixed-valence (L . I-2)(L(2))(2+). 2I(3)(-) compound has been prepared. (L . I-2)(L(2))(2+). 2I(3)(-) consists of a neutral adduct between L and a Diiodine molecule and a triiodide salt, whose dication is formed by two L molecules joined through an Se-Se bond. This is the first example of a dication bearing the -Se-Se- bridge obtained by direct oxidation of a selenic compound with Diiodine. FT-IR and FT-Raman spectra agree well with the structural features. Crystals of (L . I-2)(L(2))(2+). 2I(3)(-) are triclinic, space group , Z = 2, with unit cell dimensions a = 8.465(2), b = 10.233(3), c = 21.798(8) Angstrom, alpha = 95.81(3), beta = 90.53(2), gamma = 103.18(2)degrees, R = 0.027

  • Reactivity of 1,3,5-Trithiacyclohexane and 1,3,5-Triselenacyclohexane towards molecular Diiodine. Crystal structures of the Diiodine adducts
    Polyhedron, 1997
    Co-Authors: Massimiliano Arca, Franco Cristiani, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Gaetano Verani, Alessandra Garau, Francesco Demartin
    Abstract:

    Abstract The reactions between I2 and the donors (D) 1,3,5-trithiacyclohexane (1) and 1,3,5-triselenacyclohexane (2), in methylene chloride and hot benzene respectively (1:1 I2:D molar ratio) give the solid adducts 1·I2 (I) and 2 · I2 (II) whose structures have been solved by X-ray diffraction. The use of an excess of Diiodine up to the molar ratio 2:1 always gives II from 2, and 1·2I2 (III) from 1. Compound I consists of polymeric chains in which each Diiodine bridges between different 1 molecules, while II consists of discrete molecular units. The Raman ν(II) frequency and II bond distance in I fits well with the previously found linear correlation. This correlation suggests two different II bond distances for III. The comparison of the FTIR and FT-Raman spectra for II is consistent with the three-body model for SeII. The association constant between 1 and I2 in methylene chloride has been also studied both by UV-visible and 13C NMR spectroscopy, giving K values at 21°C in good agreement.

Francesco Demartin - One of the best experts on this subject based on the ideXlab platform.

  • A new assembly of Diiodine molecules at the triphenylphosphine sulfide template
    Journal of the Chemical Society Dalton Transactions, 1999
    Co-Authors: Massimiliano Arca, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Francesco Demartin, Alessandra Garau, Gaetano Verani
    Abstract:

    The new I2 adduct TPPS·3I2 (TPPS = triphenylphosphine sulfide) has been synthesized and characterised by X-ray diffraction on a single crystal. It consists of a TPPS·I2 1:1 molecular adduct interacting with two further Diiodine molecules in a "head to tail" sequence to give an overall TPPS·I2 ⋯ I2 ⋯ I2 arrangement in the asymmetric unit. Considering the I ⋯ I interactions below 3.6 Å, five of the six iodine atoms of the asymmetric unit are arranged in infinite polycyclic ribbons. The iodine atoms, to which the TPPS molecules are connected, are almost perpendicular appendages on opposite sides of each ribbon. Weaker interactions between the ribbons give rise to unprecedented continuous stepped layers of Diiodine molecules anchored to TPPS donor units. The structural features of TPPS·3I2 are discussed in comparison with those of the previously reported 2TPPS·3I2, TPPS-I2, TPPS·IBr and TPPS·ICl, and its FT-Raman spectrum compared with those of 2TPPS·3I2 and TPPS·I2. A re-examination of the equilibrium reaction between TPPS and I2 by 31P NMR confirms the formation of the 1:1 adduct in CH2Cl2 solution and gives a formation constant value of 137 ± 11 dm3 mol-1

  • Reactivity of 1,3,5-Trithiacyclohexane and 1,3,5-Triselenacyclohexane towards molecular Diiodine. Crystal structures of the Diiodine adducts
    Polyhedron, 1997
    Co-Authors: Massimiliano Arca, Franco Cristiani, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Gaetano Verani, Alessandra Garau, Francesco Demartin
    Abstract:

    Abstract The reactions between I2 and the donors (D) 1,3,5-trithiacyclohexane (1) and 1,3,5-triselenacyclohexane (2), in methylene chloride and hot benzene respectively (1:1 I2:D molar ratio) give the solid adducts 1·I2 (I) and 2 · I2 (II) whose structures have been solved by X-ray diffraction. The use of an excess of Diiodine up to the molar ratio 2:1 always gives II from 2, and 1·2I2 (III) from 1. Compound I consists of polymeric chains in which each Diiodine bridges between different 1 molecules, while II consists of discrete molecular units. The Raman ν(II) frequency and II bond distance in I fits well with the previously found linear correlation. This correlation suggests two different II bond distances for III. The comparison of the FTIR and FT-Raman spectra for II is consistent with the three-body model for SeII. The association constant between 1 and I2 in methylene chloride has been also studied both by UV-visible and 13C NMR spectroscopy, giving K values at 21°C in good agreement.

  • Reaction of N,N′-dimethylimidazolidine-2-selone (L) with I2. Crystal structure of the mixed-valence (L·I2)(L2)2+·2I3 − compound
    Inorganica Chimica Acta, 1997
    Co-Authors: Francesco Demartin, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Gaetano Verani
    Abstract:

    From the reaction of N,N'-dimethylimidazolidine-2-selone (L) with I-2 the mixed-valence (L . I-2)(L(2))(2+). 2I(3)(-) compound has been prepared. (L . I-2)(L(2))(2+). 2I(3)(-) consists of a neutral adduct between L and a Diiodine molecule and a triiodide salt, whose dication is formed by two L molecules joined through an Se-Se bond. This is the first example of a dication bearing the -Se-Se- bridge obtained by direct oxidation of a selenic compound with Diiodine. FT-IR and FT-Raman spectra agree well with the structural features. Crystals of (L . I-2)(L(2))(2+). 2I(3)(-) are triclinic, space group , Z = 2, with unit cell dimensions a = 8.465(2), b = 10.233(3), c = 21.798(8) Angstrom, alpha = 95.81(3), beta = 90.53(2), gamma = 103.18(2)degrees, R = 0.027

  • charge transfer complexes of benzoxazole 2 3h thione and benzoxazole 2 3h selone with Diiodine x ray crystal structure of benzoxazole 2 3h thione bis Diiodine
    Polyhedron, 1995
    Co-Authors: Franco Cristiani, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Gaetano Verani, Francesco Demartin
    Abstract:

    Abstract Solids of stoichiometry 1·I2 (C7H5I2NOS; I), 1·2I2 (C7H5I4NOS; II), 2·I2 (C7H5I2NOSe; III) and 2·2I2 (C7H5I4NOSe; IV) have been obtained by reacting respectively benzoxazole-2(3H)-thione (1) and benzoxazole-2(3H)-selone (2) with molecular Diiodine in a 1:1 or 1:2 molar ratio in CH2Cl2 solution. Crystals suitable for X-ray structure determination have been obtained only for II and contain units formed by one Diiodine molecule bonded almost linearly [178.44(4)°] to the thionic sulphur atom of 1 and another Diiodine molecule weakly interacting with the former. The FT-Raman spectrum in the characteristics v(I-I) region shows two bands for compound II at 176 and 159 cm−1, in accordance with the presence of two differently perturbed Diiodine molecules [ I (1)– I (2) = 2.769(1) A , I (3)– I (4) = 2.729(1) A ] . The FT-IR and FT-Raman spectra of compounds I, III and IV are discussed in comparison with the spectrum of II and with those reported for similar charge transfer complexes.

  • Charge transfer complexes of benzoxazole-2(3H)-thione and benzoxazole-2(3H)-selone with Diiodine: X-ray crystal structure of benzoxazole-2(3H)-thione bis(Diiodine)
    Polyhedron, 1995
    Co-Authors: Franco Cristiani, Francesco A. Devillanova, Francesco Isaia, Vito Lippolis, Gaetano Verani, Francesco Demartin
    Abstract:

    Solids of stoichiometry 1 . I-2 (C7H5I2NOS; I), 1 . 2I(2) (C7H5I4NOS; II), 2 . I-2 (C7H5I2NOSe; III) and 2 . 2I(2) (C7H5I4NOSe; IV) have been obtained by reacting respectively benzoxazole-2(3H)-thione (1) and benzoxazole-2(3H)-selone (2) with molecular Diiodine in a 1:1 or 1:2 molar ratio in CH2Cl2 solution. Crystals suitable for X-ray structure determination have been obtained only for II and contain units formed by one Diiodine molecule bonded almost linearly [178.44(4)degrees] to the thionic sulphur atom of 1 and another Diiodine molecule weakly interacting with the former. The FT-Raman spectrum in the characteristic nu(I-I) region shows two bands for compound II at 176 and 159 cm(-1), in accordance with the presence of two differently perturbed Diiodine molecules [I(1)-I(2) = 2.769(1) Angstrom, I(3)-I(4) = 2.729(1)Angstrom]. The FT-IR and FT-Raman spectra of compounds I, III and IV are discussed in comparison with the spectrum of II and with those reported for similar charge transfer complexes