Catalytic performance of iridium supported on SiO2 was investigated for 5hydroxymethylfurfural (HMF) transformation. Ir/SiO2 catalysts exhibiting different metal loading (1, 3, and 5 wt.%) were tested in the preliminary experiments in the hydrogenation of two probe molecules, e.g. ethyl pyruvate (EP) and ketopantolactone (KP) to evaluate the Ir dispersion on the catalyst activity in C=O hydrogenation. In the transformation of HMF the influence of metal dispersion, iridium precursor and addition of H2SO4 were studied revealing that 2,5-bis-(hydroxymethyl)furan (BHMF) was the main product with 83% selectivity at 70% conversion of HMF over chlorine free Ir/SiO2 together with H2SO4 at 333 K in THF under 10 bar hydrogen. On the other hand, one-pot synthesis of HMF to 2,5dimethylfuran (DMF) was promoted in the presence of chlorine containing Ir/SiO2(Cl) and H2SO4. Both of these products are considered high value-added chemicals from biomassderived 5-hydroxymethylfurfural. The exposed iridium atoms together with the total acid sites are an important catalytic descriptor for hydrogenation of HMF to BHMF.

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The syntheses and crystal structures of two novel trisamides, the ethyl- (2) and propyl-substituted (3) N,N′,N′′-trialkylbenzene-1,3,5-carboxamides, are reported. The compounds are prepared in good yields by aminolysis of the trimethyl-1,3,5-benzenecarboxylate and the respective primary amine. Compound 2 crystallizes in the P212121 space group with a complete molecule in the asymmetric unit and four molecules per unit cell, whereas 3 does it in the R3c space group with one-third of the molecule in the asymmetric unit and six molecules per unit cell. Their solid-state structures show that the NH···OC hydrogen bond plays the most important role in the supramolecular framework of both cases, despite considerable differences in crystal packing. Supramolecular sheets are formed in 2, whereas molecules of 3 are packed in a H-bonded primitive cubic [46] three-dimensional network. The main difference in the molecular conformation is the tilting of the carboxamide group with respect to the aryl, which in the case of 3 occurs in the same direction, leading to the formation of “solid-state” chiral molecules.

A relatively large number of mesomorphic compounds containing heterocyclic units have been synthesized and interest in such structures constantly grows [l, 21. This is not only because of the greater possibilities with heterocyclic rings for the design of new mesogenic molecules, but also because the introduction of heteroatoms can cause considerable changes in polarity, polarizability and sometimes the geometry of a molecule in relation to the geometry with phenyl rings [3, 41. These can greatly influence the types of mesophases which occur, the phase transition temperatures, and the dielectric and other properties of the mesogens [5, 61. Continuing our investigations of compounds with heterocyclic rings [7, 81 we have synthesized new Schiff's bases mesogenic derivatives of 5-(p-n-alkoxy)phenyl-2-amino-l,3,4-thiadiazole. SynthesisSchiff's bases 5a-5f were synthesized according to Scheme I. 1-4 were synthesized through the detailed procedures described in reference [9].The structures for all these compounds were confirmed by IR (Perkin-Elmer 577), 'H NMR, 13C NMR (Bruker AC-250 MHz), using tetramethylsilane as the standard, and elementary analyses ( Table 1).

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