312962-45-1Relevant academic research and scientific papers
Controlled formation and topologies of thiophenolate-based macrocycles: Rings, cylinders and bowls
Christensen, Aase,Mayer, Christoph,Jensen, Frank,Bond, Andrew D.,McKenzie, Christine J.
, p. 108 - 120 (2006)
The Schiff-base condensations of 1,3-diaminopropane with a protected thiophenol dialdehyde in the presence of Ni2+, Pd2+ or Zn2+ can be controlled to yield either mononuclear acyclic, or 2 + 2 and 4 + 4 macrocyclic complexes by the choice of both metal cation and counteranion. The Ni2+ complex of the 2 + 2 macrocycle contains two square-planar nickel ions and shows an arrangement similar to one observed previously: the μ-S atoms of the thiophenolate groups are pyramidal and lie on the same side of the plane defined by the four N atoms of the macrocycle to give a V-shaped molecule. By contrast, the Zn2+ complex of the 2 + 2 macrocycle undergoes oligomerisation to yield a bowl-shaped hexanuclear complex that includes a μ3-carbonate anion. Essential for this topology is the presence of three μ3-S-thiophenolato groups that link the three macrocyclic units to form a Zn3S3 ring that seals the bottom part of the bowl. In this arrangement, one of the pyramidal μ3-S atoms in each dinuclear Zn2+ complex is inverted relative to the arrangement observed for the dinickel complexes. Molecular modelling suggests that inversion about the μ-S atoms of the 2 + 2 macrocyclic complexes is readily accessible at room temperature and that the contrasting arrangements observed for the Ni2+ and Zn2+ complexes are those energetically most favourable for the respective metal ions. Rare 4 + 4 macrocyclic complexes are isolated as neutral dinuclear complexes for Ni2+ and Pd2+ and as a tetranuclear complex cation for Zn2+. The topologies of these systems contrast significantly: those with two square-planar Ni2+ or Pd2+ ions form extended rings, while that with Zn2+ forms a sulfur-lined cylinder which hosts acetonitrile molecules in the crystalline state. Reaction conditions can also be optimised to produce 2 + 1 acyclic ligands as their mononuclear Ni 2+ and Pd2+ complexes, providing potentially useful building blocks for production of more complicated macrocyclic and supramolecular systems. The Royal Society of Chemistry 2006.
Conversion of some substituted phenols to the corresponding masked thiophenols, synthesis of a dinickel(n) dithiolate macrocyclic complex and isolation of some metal- And ligand-based oxidation products
Brooker, Sally,Caygill, Graham B.,Croucher, Paul D.,Davidson, Tony C.,Clive, Derrick L. J.,Magnuson, Stephen R.,Cramer, Stephen P.,Ralston, Corie Y.
, p. 3113 - 3121 (2007/10/03)
A modified preparation of the masked thiolate head unit 5-(2, 6-diformyl-4-methyIphenyl) dimethylthiocarbamate 6 is detailed and two new masked thiolate head units, 5-(2, 6-diformyl-4-tert-butylphenyl) dimethylthiocarbamate 7 and S-(2-formylphenyl) dimethylthiocarbamate 8, are prepared by this method. The synthesis, crystal structure, NMR spectra and electrochemical properties of the first macrocyclic complex to be derived from 7, [Ni2Ll](GO4)2, are discussed. Oxidation of [Ni2L2](CF3SO3)2 (L22- is derived from 6 and 1, 3-diaminopropane) with cerium(iv) ammonium nitrate led to the precipitation of the black complex [Ni2L2][Ce(NO3)6], which is believed to contain a single nickel(in) centre. This complex decomposes in DMF over time (24 hours) to form the red dinickel(n) complex [Ni2L2](NO3)2-2DMF which has been structurally characterised. Oxidation of [Ni2L3](CF3SO3)2 (L32- is derived from 6 and 1, 4-diaminobutane) with I2 results in ligand oxidation forming the metal free macrocycle (L3')2t which contains two five membered isothiazole rines. This is confirmed by the X-ray crystal structure determinations of (L3')(I, ), and (L3')(I):(I2)5. The Royal Society of Chemistry 2000.
