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C49H62N2O14, orthorhombic, P212121 (no. 19), a = 9.46370(3)Å, b = 12.29468(3) Å, c = 40.46176(4) Å, V = 4707.9 Å3, Z = 4, Rgt(F) = 0.102, wRref(F) = 0.099, T = 150 K.

C36.50H46BrN5O5.50, orthorhombic, P212121 (no. 19), a = 9.771(3) Å, b = 19.853(2) Å, c = 20.763(3) Å, V = 4027.7 Å3, Z = 4, Rgt(F) = 0.046, wRref(F) = 0.056, T = 293 K.

C18H24N2O3, orthorhombic, P212121 (no. 19), a = 9.868(1) Å, b = 10.877(1) Å, c = 15.458(2) Å, V = 1659.1 Å3, Z = 4, Rgt(F) = 0.065, wRgt(F) = 0.079, T = 293 K.

Organised mesoporous alumina-supported Mo sulfide catalysts were prepared by the conventional impregnation with solution of ammonium heptamolybdate and by the method of thermal spreading of MoO3. The mesoporous alumina (surface area 400–600 m2 g−1, pore diameter 3–4.5 nm) exhibited much higher capacity for dispersion of Mo species than the conventional alumina. The activity in thiophene hydrodesulfurization of highly loaded mesoporous alumina-supported catalysts with the MoO3 content of 30 wt.% was almost two times higher than the activity of the conventional industrial Mo/Al2O3 containing 15 wt.% of MoO3 [Copyright &y& Elsevier]

Nucleophilic fluorination of secondary aliphatic substrates, especially of halides, still remains a challenge. Among the available reagents, TBAT belongs to one of the best choices due to its stability, affordable price and low toxicity. With the aim to improve its selectivity, we synthesized three analogues modified in the aryl part of the TBAT reagent with one or two electron donating methoxy groups or with one electron withdrawing trifluoromethyl group. All three reagents are air-stable compounds and their structure was confirmed by a single crystal X-ray analysis. In testing the reactivity and selectivity of the reagents with a library of secondary bromides, as well as of other selected primary and secondary substrates, we found that substitution with methoxy groups mostly improves both reactivity and selectivity compared to TBAT, while the substitution with trifluoromethyl group leads to inferior results. Difluorosilicates modified by more than two electron donating methoxy groups proved to be unstable and decomposed spontaneously to the HF 2 - anion. DFT calculations of tetramethylammonium analogues of the studied reagents disclosed that the substitution of the phenyl group with the methoxy substituent lowers the transitions state energy of the decomposition to a fluorosilane-fluoride complex, while the substitution with the trifluoromethyl group has an opposite effect., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

A starting thiacalix[4]arene can be easily transformed into oxidized phenoxathiin-based macrocycles 9 and 9', representing an unusual structural motif in calixarene chemistry. The presence of electron-withdrawing groups (SO 2 , SO) and the considerable internal strain caused by the condensed heterocyclic moiety render these molecules susceptible to nucleophilic attack. The reaction with various organolithium reagents provides a number of different products resulting from the cleavage of either the calixarene skeleton or the phenoxathiin group or both ways simultaneously. This enables the preparation of thiacalixarene analogues with unusual structural features, including systems containing a biphenyl fragment as a part of the macrocyclic skeleton. The above-described transformations, unparalleled in classical calixarene chemistry, clearly demonstrate the synthetic potential of this thiacalixarene subgroup., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

A Sonogashira coupling of meta -iodocalix[4]arene with various terminal acetylenes confirmed that the meta position of calixarene is well addressable, and that both thermal and microwave protocols led to good yields of alkynylcalixarenes. Alkynes thus obtained were subjected to the ferric chloride and diphenyl diselenide-promoted electrophilic closure. It turns out that the calix[4]arenes give completely different bridging products than those described for the non-macrocyclic starting compounds. This can be demonstrated not only by the isolation of products with a six-membered ring ( 6-exo-dig ), but mainly by the smooth formation of the 5-endo-dig cyclization, which has never been observed in the aliphatic series. An attempt at electrocyclization led to a high yield of the 1,2-diketone (oxidation of the starting alkyne), again in contrast to the reaction described for the acyclic derivatives. The structures of the unexpected products were unequivocally established by X-ray analysis and clearly demonstrate how the preorganized macrocyclic skeleton favors a completely different regioselectivity of cyclization reactions compared to common aliphatic compounds.