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Sergio Baggio

Publications and source records attributed to Sergio Baggio.

At least 19 recordsLinked to original sources
PubMed2006

A new simplifying approach to molecular geometry description: the vectorial bond-valence model.

A method to describe, analyze and even predict the coordination geometries of metal complexes is proposed, based on previous well established concepts such as bond valence and valence-shell electron-pair repulsion (VSEPR). The idea behind the method is the generalization of the scalar bond-valence concept into a vector quantity, the bond-valence vector (BVV), with the innovation that the multidentate ligands are represented by their resultant BVVs. Complex n-ligand coordination spheres (frequently indescribable at the atomic level) reduce to much simpler ones when analyzed in BVV space, with the bonus of a better applicability of the VSEPR predictions. The geometrical implications of the BVV description are analyzed for the cases of n=2 and 3 (n=number of ligands), and the validity of its predictions, checked for a large number of metal complexes.

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PubMed2006

Triaquamanganese sulfite revisited.

Orthorhombic Mn(SO3)(H2O)3 has been reinvestigated by single-crystal X-ray diffraction in two possible space groups, viz. P2(1)2(1)2(1) (with all atoms in general positions) and Pnma (with the molecule bisected by a mirror plane). The results confirm the lower symmetry assigned in a previous single-crystal neutron diffraction study. However, the refinement of the P2(1)2(1)2(1) model requires the introduction of racemic twinning and soft positional and displacement restraints for the H atoms. The importance of a scrupulous report on symmetry absence violations as standard policy in crystallographic work is discussed.

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PubMed2006

Aqua(thiosulfato-kappa2O,S)[2,4,6-tri-2-pyridyl-1,3,5-triazine-kappa3N2,N1,N6]zinc(II) hemihydrate.

The title compound, [Zn(S2O3)(C18H12N6)(H2O)].0.5H2O, contains two almost identical independent monomeric moieties composed of an octahedral Zn centre coordinated by a tridentate 2,4,6-tri-2-pyridyl-1,3,5-triazine (tpt) ligand, one aqua ligand and an O,S-chelating thiosulfate anion. The structure is stabilized by a solvent water molecule. Multiple strong hydrogen bonds with additional weaker pi-pi interactions between tpt groups define a multiple column spatial organization.

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PubMed2006

Di-mu2-sulfito-kappa8O,O':O',O''-bis[(2,4,6-tri-2-pyridyl-1,3,5-triazine-kappa3N2,N1,N6)cadmium(II)] octahydrate.

The title compound, [Cd2(SO3)2(C18H12N6)2].8H2O, is a dimer built up around a symmetry center, where the sulfite anion displays a so far unreported coordination mode in metal-organic complexes; the anion binds as a mu2-sulfite-kappa4O,O':O',O'' ligand to two symmetry-related seven-coordinate Cd(II) cations, binding through its three O atoms by way of two chelate bites with an O atom in common, which acts as a bridge. The cation coordination is completed by a 2,4,6-tri-2-pyridyl-1,3,5-triazine ligand acting in its usual tridentate mode.

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PubMed2005

catena-poly[[aqua(3,4,7,8-tetramethyl-1,10-phenanthroline-kappa2N,N')cadmium(II)]-mu3-thiosulfato-kappa3S:S:O].

The title compound, [Cd(S(2)O(3))(C(16)H(16)N(2))(H(2)O)](n), presents a polymeric one-dimensional structure running along the P2(1)/c glide direction, with elementary units defined by six-coordinate Cd(II) atoms bonded to three symmetry-related thiosulfate groups, a bidentate tetramethylphenanthroline ligand and one aqua ligand. The bridging thiosulfates bind metal centers through two different sequences, viz. Cd-S-Cd' and Cd'-S'-S'-O'-Cd, defining a closed six-membered ring. Individual chains are held together via pi-pi interactions to generate two-dimensional networks parallel to the (100) plane. These, in turn, are connected by much weaker van der Waals interactions.

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PubMed2005

Bis[(acetato-kappa(2)O,O')bis(4,4'-dimethyl-2,2'-bipyridyl-kappa(2)N,N')zinc(II)] trithionate pentahydrate.

The title ionic zinc-acetate complex, [Zn(C2H3O2)(C12H12N2)2]2(S3O6).5H2O, contains a ZnN4O2 nucleus provided by the three bidentate ligands acting in a chelating mode. The trithionate unit, in turn, acts as an isolated charge-balancing counter-ion. The structure has a three-dimensional assembly achieved through three different interaction types, viz. Coulomb, hydrogen bonding and pi-pi. The trithionate group and one of the solvent water molecules are disordered around inversion centers.

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PubMed2005

Two Cd and Hg peroxodisulfate complexes with aromatic amines.

The crystal structures of two complexes containing the peroxodisulfate anion are reported, namely mu-peroxodisulfato-1kappaO:2kappaO'-bis[(acetato-kappa2O,O')aqua(2,2':6',2''-terpyridine-kappa3N,N',N'')cadmium(II)] heptahydrate, [Cd2(C2H3O2)2(S2O8)(C15H11N2)2(H2O)2].7H2O, (I), and catena-poly[[[bis(2,2'-bipyridine-kappa2N,N')mercury(II)]-mu-peroxodisulfato-kappa2O:O'] 0.4-hydrate], {[Hg(C10H8N2)2(S2O8)].0.4H2O}n, (II). In both structures, the anion behaves as a bridge, linking neighbouring coordination polyhedra in two different ways, either tightly bound to the heptacoordinated Cd2+ cation forming neatly separated dimeric entities in (I) or across a shorter O-S-O path producing weakly connected chains by way of 'semicoordination' to the Hg2+ cations in (II).

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PubMed2004

Di-mu-sulfito-bis[(4,4'-dimethyl-2,2'-bipyridine)zinc(II)] dihydrate and poly[[aqua(1,10-phenanthroline)zinc(II)]-mu3-sulfito-zinc(II)-mu3-sulfito].

Two different zinc sulfite compounds have been prepared through the decomposition of pyrosulfite-dithionite ions in aqueous solution, viz. a dimeric complex, di-mu-sulfito-kappa3O,O':O'';kappa3O:O',O''-bis[(4,4'-dimethyl-2,2'-bipyridine-kappa2N,N')zinc(II)] dihydrate, [Zn2(SO3)2(C12H12N2)2].2H2O, (I), which was solved and refined from a twinned sample, and an extended polymer, poly[[aqua(1,10-phenanthroline-kappa2N,N')zinc(II)]-mu3-sulfito-kappa2O:O':O''-zinc(II)-mu3-sulfito-kappa3O:O:O'], [Zn2(SO3)2)(C12H10N2)(H2O)]n, (II). In (I), the dinuclear Zn(II) complex has a center of symmetry. The cation is five-coordinate in a square-pyramidal arrangement, the anion fulfilling a bridging chelating role. Compound (II) comprises two different zinc units, one being five-coordinate (square pyramidal) and the other four-coordinate (trigonal pyramidal), and two independent sulfite groups with different binding modes to the cationic centers.

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PubMed2004

Tetraaqua(3,4,7,8-tetramethyl-1,10-phenanthroline-kappa2N,N')zinc(II) thiosulfate.

In the title complex of zinc(II) with 3,4,7,8-tetramethyl-1,10-phenanthroline (tmph), viz. [Zn(C16H16N2)(H2O)4](S2O3), the metal atom has a monomeric octahedral ZnN2O4 complex environment comprising two N-atom donors from the tmph group and four aqua O-atom donors. The complex cation is connected to four thiosulfate anions through a compact hydrogen-bonding network involving all coordinated aqua H-atom donors and all the outer acceptors (O and S) of the anion.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2004

A novel five-coordinate cadmium phenanthroline thiosulfate.

The structure of the novel cadmium phenanthroline thiosulfate poly[[(1,10-phenanthroline-kappa(2)N,N')cadmium(II)]-micro(3)-thiosulfato-kappa(3)S:S:O], [Cd(S(2)O(3))(C(12)H(8)N(2))](n), with a pentacoordinated Cd centre, is reported. It forms linear chains built up around a 2(1) axis and is isostructural with the known bipyridine homologue. The structure is also compared with a previously reported closely related monoaqua monohydrated phase, where the Cd(2+) cation is hexacoordinated. The incidence of weak C-H.O interactions in the determination of its general packing properties is discussed.

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PubMed2003

[2,6-Bis(1H-benzimidazol-2-yl-kappaN3)pyridine-kappaN](dimethylformamide-kappaO)(thiosulfato-kappa2O,S)nickel(II) monohydrate.

The structure of the title compound, [Ni(ths)(bbip)(dmf)].H(2)O [ths is thiosulfate, S(2)O(3); bbip is 2,6-bis(1H-benzimidazol-2-yl)pyridine, C(21)H(13)N(5); and dmf is dimethylformamide, C(3)H(7)NO], is monomeric, with the nickel ion octahedrally surrounded by an N,N',N"-tridentate bbip molecule, an S,O-bidentate ths molecule and an O-monodentate dmf molecule. The H atoms of the hydration water molecule and the amino groups of bbip are involved in hydrogen bonding and determine a spatial organization of broad layers parallel to (001), which are connected by weak interactions.

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PubMed2003

Bis[2,6-bis(1H-benzimidazol-2-yl-kappaN(3))pyridinato-kappaN]zinc(II).

The structure of [Zn(C(19)H(12)N(5))(2)], which is monomeric and consists of neutral Zn(bbip-H)(2) entities [bbip-H is the anionic form of bis(benzimidazolyl)pyridine, formed by the loss of one H atom], has been solved from a racemic twin. The Zn atom lies at a site with imposed 222 symmetry and the bbip-H ligand has imposed twofold symmetry. The imidazolyl H atom is disordered over two symmetry-related positions, thus raising the molecular symmetry as required by the space group. The angle between the planes of the two coordinated bbip-H ligands is 84.6 (3) degrees, so defining a distorted octahedral environment around the metal atom.

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PubMed2003

Two hydrates of 2,6-bis(1H-benzimidazol-2-yl)pyridine.

The structures of the mono- and sesquihydrates of 2,6-bis(1H-benzimidazol-2-yl)pyridine (bbip) are reported. Phase (I), C(19)H(13)N(5).H(2)O, has one water and one bbip molecule in the asymmetric unit, while phase (II), C(19)H(13)N(5).1.5H(2)O, has three water molecules and two bbip molecules in the asymmetric unit. The compounds exhibit very similar molecular geometries but different packing organizations, which result from intricate hydrogen-bonding schemes.

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PubMed2003

Two new dimeric cadmium(II) and zinc(II) sulfate complexes with 2,4,6-tris(2-pyridyl)-1,3,5-triazine and 2,2:6',2"-terpyridine.

The structures of two new sulfate complexes are reported, namely di-mu-sulfato-kappa(3)O,O':O"-bis(aqua[2,4,6-tris(2-pyridyl)-1,3,5-triazine-kappa(3)N(1),N(2),N(6)]cadmium(II)) tetrahydrate, [Cd(2)(SO(4))(2)(C(16)H(12)N(6))(2)(H(2)O)(2)].4H(2)O, and di-mu-sulfato-kappa(2)O:O'-bis[(2,2':6',2"-terpyridine-kappa(3)N(1),N(1'),N(1"))zinc(II)] dihydrate, [Cd(2)(SO(4))(2)(C(15)H(11)N(3))(2)].2H(2)O, the former being the first report of a Cd(tpt) complex [tpt is 2,4,6-tris(2-pyridyl)-1,3,5-triazine]. Both compounds crystallize in the space group P-1 and form centrosymmetric dimeric structures. In the cadmium complex, the metal center is heptacoordinated in the form of a pentagonal bipyramid, while in the zinc complex, the metal ion is in a fivefold environment, the coordination geometry being intermediate between square pyramidal and trigonal bipyramidal. Packing of the dimers leads to the formation of planar structures strongly linked by hydrogen bonding.

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