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This research deals with 4-substituted 1,2,4-triazoles (4Rtrz) based inorganic molecular materials. This family of compounds has been built around iron(II) polymeric compounds due to their potential applications as spin transition (ST) switches and is now extending to magnetic, optical, thermal, etc. properties of coordination compounds in general. The heterobifunctional ligands used are substituted with carboxylic or tetrazole acid groups. The firsts are derivatives from linear aliphatic amino acids and allowed the discovery of iron(II) ST coordination polymers (CPs) and copper(II) CPs of various dimensionality. The triazole-tetrazole ligand, also used with azabenzene coligands, participates to many compounds with alkali, alkaline earth or transition metal. Those from cadmium(II) were specially highlighted for their luminescent properties. Alongside, the difficult crystal obtainment of linear ST iron(II) compounds with 4Rtrz has been achieved in gels with 4-amino-1,2,4-triazole. Throughout this work, crystal growth and structure determination by X-ray diffraction of the materials support the development of understanding for structure-properties relationships., Cette recherche traite de matériaux moléculaires inorganiques à base de 1,2,4-triazoles substitués en position 4 (4Rtrz). Cette famille de composés s’est construite autour des composés polymériques du fer(II) en raison de leurs potentialités comme commutateurs à transition de spin (TS) et se déploie autour des propriétés magnétiques, optiques, thermiques, etc. des composés de coordination en général. Les ligands hétérobifonctionnels introduits comprennent des substituants acides carboxyliques ou tétrazole. Les premiers, dérivés d’acides aminés aliphatiques linéaires, ont permis de découvrir des polymères de coordination (CPs) à TS du fer(II) et des CPs du cuivre(II) de différentes dimensionnalités. Le triazole-tétrazole, aussi employé avec des coligands azabenzènes, participe à de nombreux composés avec les métaux alcalins, alcalino-terreux ou de transition. Ceux du cadmium(II) ont notamment été mis en avant pour leurs propriétés de luminescence. En parallèle, la difficile obtention de cristaux de composés linéaires du fer(II) à TS avec des 4Rtrz a été réussie dans des gels avec le 4-amino-1,2,4-triazole. Tout au long de ce travail, la cristallogenèse et les résolutions structurales par diffraction des rayons X sont le support au développement de la compréhension des relations entre structures et propriétés des matériaux., (SC - Sciences) -- UCL, 2016

Attempts to synthesize Au–Pd heterometallic compounds from homonuclear palladium or gold complexes, [Pd(PtBu2)2] and [Au(PPh3)Cl] in a tetrahydrofuran (THF) solution under a CO atmosphere resulted in a homonuclear Pd cluster, namely pentakis(-carbonyl-2C:C)tetrakis(triphenylphosphane-P)- tetrapalladium(5 Pd—Pd) tetrahydrofuran disolvate, [Pd4(CO)5(C18H15P)4]-2C4H8O. The complex molecule lies on a twofold rotation axis. The crystal structure is described in relation to the CH2Cl2 solvate previously determined by our group [Willocq et al. (2011). Inorg. Chim. Acta, 373, 233–242], and in particular to the desolvated structure [Feltham et al. (1985). Inorg. Chem. 24, 1503–1510]. It is assumed that the title compound transforms into the latter structure, upon gradual loss of solvent molecules. In the title compound, the symmetry-unique THF solvent molecule is linked to the complex molecule by a weak C—H O hydrogen bond. Contributions of disordered solvent molecules to the diffraction intensities, most likely associated with methanol, were removed with the SQUEEZE [Spek (2015). Acta Cryst. C71, 9–18] algorithm.

A mononuclear iron(II) neutral complex (1) is screened for sensing abilities for a wide spectrum of chemicals and to evaluate the response function toward physical perturbation like temperature and mechanical stress. Interestingly, 1 precisely detects methanol among an alcohol series. The sensing process is visually detectable, fatigue-resistant, highly selective, and reusable. The sensing ability is attributed to molecular sieving and subsequent spin-state change of iron centers, after a crystal-to-crystal transformation.

Relatively easy-to-run synthetic routes to new mono- [1-(2-(4,5-dihydro-1H-imidazol-1-yl)ethyl)-1H-tetrazole (1) and 3-(2-(1H-tetrazol-1-yl)ethyl)oxazolidin-2-one (13)], and bis-tetrazole [N,N-bis(2-(1H-tetrazol-1-yl)ethyl)- formamide (2), bis(2-(1H-tetrazol-1-yl)ethyl)amine (3), N-(2-(1H-tetrazol-1-yl)ethyl)-N-(2-(2-(1H-tetrazol-1-yl)- ethylamino)ethyl)formamide (5), N1,N2-bis(2-(1H-tetrazol-1-yl)ethyl)ethane-1,2-diamine (6), N,N0-(2,20- azanediylbis(ethane-2,1-diyl))bis(N-(2-(1H-tetrazol-1-yl)ethyl)formamide) (8) and N1-(2-(1H-tetrazol-1-yl)ethyl)- N2-(2-(2-(1H-tetrazol-1-yl)ethylamino)ethyl)ethane-1,2-diamine (9)] ligands have been developed. 2 (whose crystal structure is described), 3, 5, 6, 8 and 9 are of particular interest as precursors for further functionalization due to the aldehyde and secondary amine functions, while 2, 5, 8 and 13 are potential synthons for the formation of ditopic ligands for metal–organic framework construction. Unexpected instability of Boc under basic and nucleophilic conditions at high temperature followed by fragmentation of tert-butyl 2-chloroethyl(2-(2-chloroethylamino)ethyl)carbamate (14) and tert-butyl 2,20-azanediylbis(ethane-2,1- diyl)bis(2-chloroethylcarbamate) (15) afforded 13, whose crystal structure is presented.

Highly functionalised benzofurans have been prepared from ortho-hydroxyphenones and 1,1-dichloroethylene. The key intermediate, a chloromethylene furan, smoothly rearranged into the corresponding benzofuran carbaldehyde under acidic conditions. Some mechanistic investigations have been performed and several biologically active benzofurans have been synthesised.

Experimental approaches to tetraphosphonate cavitands bearing fluorenyl-phosphonate bridges are reported. Different routes are described depending on the substitution on the cavitand structure. Tetra-, tri- and di-bridged phosphonate cavitands have been prepared as precursors of fluorescent hosts, for which the stereochemistry is highly dependent on the substitution at the wide rim of the resorcin[4]arene scaffold. The conformational change in 3io tetraphosphonate cavitands has been characterised by X-ray diffraction. These new molecular receptors have been used for the recognition of acetylcholine. © 2013 Copyright Taylor and Francis Group, LLC.