Résumés Année 2000

"Charge Assisted N-H(+)---O(-) and O-H---O(-) Hydrogen Bonds Control the Supramolecular Aggregation of Ferrocene Dicarboxylic Acid and Bis-amidines"

D. BRAGA, A. DE CIAN, O. FELIX, J. FISCHER, M. W. HOSSEINI, F. GREPIONI, L. MAINI, N. J. Chem., 2000, 24, 547-553. (download .pdf)

Abstract : The utilization of directional hydrogen bonds reinforced by charge assistance in the presence of anion-cation interactions permit the design and synthesis of a whole family of new organic-organometallic supersalts. The compounds [C5H16N4]2+[(η5-C5H4COO)2Fe]2-.2(C2H5OH) 1, [C5H16N4]2+{[(η5-C5H4COOH)(η5-C5H4COO)¬Fe]2}2- 2, [C7H20N4]2+ [(η5-C5H4COO)2Fe]2-.4H2O 3, [C7H20N4]2+ {[(η5-C5H4COOH)(η5-C5H4COO)Fe]2}2- 4, and [C7H18O2N4]2+ [(η5-C5H4COO)2Fe]2-.4H2O 5 have been obtained by reacting [(η5-C5H4COOH)2Fe] with the bis-amidines [C5H14N4], [C7H18N4] and [C7H16O2N4].The self-assembly between mono- and di-deprotonated acids and the protonated cations is controlled by the stoichiometric ratio and by the choice of solvent. The effect of ‘charge assistance’ on the N-H---O interactions has been discussed on the basis of a CSD analysis.

"Synthesis and solid state structural analysis of exo-bisbidentate ligands based on []metacyclophane in 1,3-alternate conformation bearing 2,2'-bipyridine or bisquinoline chelates"

C. KLEIN, E. GRAF, M. W. HOSSEINI, G. MISLIN, A. DE CIAN, Tetrahedron Lett., 2000, 41, 9043-9047.(download .pdf)

Abstract : The synthesis and structural analysis of two new exoligands 1 and 2 based on a []cyclophane backbone bearing either 2,2'-bipyridine or bisquinoline chelating units have been achieved.

"Metallacyclophanes formed by a tetrapyrazolyl ligand and copper (II) cation"

A. JOUAITI, M. LOï, M. W. HOSSEINI and A. De CIAN, J. Chem. Soc., Chem. Commun., 2000, 2085-2086. (download .pdf)

Abstract : Using a tetrakis-pyrazolylbenzene ligand and CuCl2 or Cu(CF3SO3-)2 salts, binuclear metallamacrocycles of the cyclophane type have been exclusively obtained. Structural characterisation by X-ray on single-crystal reveals that in both cases, Cl- or triflate anions are coordinated to Cu metal centres adopting the square pyramid coordination geometry.

"Design, Synthesis and Structural Investigation of a 2-D Coordination Network Based on the Self-assembly of Tetracarboxylate Derivative of Tetrathiacalix[4]arene and Silver Cation"

H. AKDAS, E. GRAF, M. W. HOSSEINI, A. De CIAN and L. McB. HARROWFIELD, J. Chem. Soc., Chem. Commun., 2000, 2219-2220. (download .pdf)

Abstract: The fully deprotonated tetrathiacalix[4]arene 14- in 1,3-alternate conformation and bearing four carboxylate units was shown to act as a tecton leading in the presence of Ag+ cation to a 2-D coordination network in the crystalline phase which was described as discrete binuclear [14-, (Ag+)2]2- complexes interconnected by Ag+ cations.

"Directional 1-D Inclusion Networks: self-assembly of unsymmetrical Koilands into Directional koilates in th e crystalline phase"

J. MARTZ, E. GRAF, M. W. HOSSEINI, A. De CIAN, J. FISCHER, J. Chem. Soc. Dalton Trans., 2000, 3791-3796. (download .pdf)

Abstract : An unsymmetrical koiland 5 based on the double fusion of two different calix[ 4]arenes by two silicon atoms was prepared and structurally characterised. Using p-xylene as a symmetrical or phenylpropyne as an unsymmetrical connectors directional 1-D inclusion networks were obtained and structurally characterised by X-ray diffraction methods on single-crystals. In both cases, the 1-D networks were packed in a parallel fashion. However, the linear arrays were oriented in opposite directions, thus, leading to non directional systems.

"Design, Synthesis and Structural Investigation of a 1-D Directional Coordinatio n Network Based on the Self-assembly of an Unsymmetrical Mono-tridentate ligand and Cobalt Cation"

A. JOUAITI, M. W. HOSSEINI and A. De CIAN, J. Chem. Soc., Chem. Commun., 2000, 1863-1864. (download .pdf)

Abstract: Using an exo ligand containing a pyridine unit as a monodentate coordination site and a PyS2 moiety as a tridentate coordination pole, a directional 1-D coordination network was obtained in the presence of CoCl2 under self-assembly conditions. The X-ray study on single-crystal revealed that in the crystalline phase the 1-D networks were packed in a centrosymmetric fashion.

"Crystal engineering of 2-D hydrogen bonded molecular networks based on the self-assembly of anionic and cationic modules"

O. FELIX, M. W. HOSSEINI, A. DE CIAN, J. FISCHER, J. Chem. Soc., Chem. Commun., 2000, 281-282. (download .pdf)

Abstract: Using a self-assembly strategy based on both H-bonding and ionic interactions, a molecular module composed of two cyclic amidinium units and that bears two additional OH groups, thus possessing a total of six H-bond donor sites, was used to engineer 2-D crystalline molecular networks in the presence carboxylate anions.

"Metallatubulane: Synthesis and structural analysis of an infinite tubular coordination network formed by the self-assembly of a tetracyanocyclophane and silver cations"

C. KLEIN, E. GRAF, M. W. HOSSEINI, A. DE CIAN, J. FISCHER, J. Chem. Soc., Chem. Commun., 2000, 239-240. (download .pdf)

Abstract: Using a [1,1,1,1]metacyclophane bearing four nitrile groups and blocked in the 1,3-alternate conformation and silver cation, a tubular coordination network formed by double bridging of consecutive rings by linearly coordinated metal centres was obtained under self-assembly conditions and structurally characterised in the solid state by an X-ray diffraction methods.

"Mercaptocalixarenes as Mercury (II) Extractants: Synthesis, Structural Analysis and Extraction Properties of Lipophilic Dimercaptocalix[4]arenes"

P. RAO, O. ENGER, E. GRAF, M. W. HOSSEINI, A. DE CIAN, J. FISCHER, Eur. J. Inorg. Chem., 2000, 1503-1508. (download .pdf)

Abstract: Lipophilic calix[4]arene derivatives that contain two O-C12 alkyl chains and two SH groups at the lower rim were synthesized and characterised in the 1,2- and partial cone conformations. Both conformers were treated with Hg2+ and formed neutral mononuclear Hg2+ complexes in which the cation was linearly coordinated to two sulphur atoms. The lipophilic dimercaptocalixarenes were shown to extract Hg2+ cation exclusively and efficiently from aqueous phase into chloroform.