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Unprecedented silanol-based bifunctional HBD catalysts with tetraalkylammonium units directly incorporated into their structures were prepared from tailor-made silanols and used in the preparation of cyclic carbonates.

The diastereoselectivity of diazomethane addition to the conjugated double bond of α,β-unsaturated sesquiterpene lactones was explored using zaluzanin A (1) as a model. Thus, the absolute configuration of 1 was assured by X-ray diffraction analysis including evaluation of Flack and Hooft parameters, and by vibrational circular dichroism spectroscopy of its diacetyl derivative 2, while the absolute configuration of the diazomethane addition product, zaluzanin A pyrazoline (3), was determined by evaluation of the 1 H NMR chemical shift changes with respect to 1, and confirmed by X-ray diffraction analysis, again including evaluation of Flack and Hooft parameters.

The synergy between porosity and soft properties in metal−organic frameworks (MOFs) can result in materials with adaptability of the pore size/shape to the adsorbate. Herein, we present a new guest-responsive flexible MOF: CCIQS-1. This material consists of threefold interpenetrated subnetworks comprising] nodes interconnected by 4,4′-(9,10-anthracenediyl)dibenzoate ligands. This arrangement gives rise to the formation of hydrophilic and hydrophobic channels. Although the activated material is permanently porous, a crystal-to-crystal phase transition takes place upon solvent removal, leading to the contraction of the hydrophobic pores while 1D hydrophilic channels remain open. As a result, CCIQS-1 exhibits a higher affinity for guests with moderate polarity [tetrahydrofuran (THF), MeOH, and acetone] than for non-polar ones (toluene, cyclohexene, and hexane). X-ray diffraction studies on the contracted-pore phase (cp-CCIQS-1) after exposure to different solvents indicate that only adsorbates with a suitable polarity and molecular size trigger the recovery of the open-pore phase (op-CCIQS-1) via the combination of a breathing effect and subnetwork displacement.

A series of borosilicates was synthesized, where the structure of the borosilicate core was easily modulated using two strategies: blocking of condensation sites and controlling the stoichiometry of the reaction. Thus, on the one hand, the condensation of phenylboronic or 3-hydroxyphenylboronic acid with diacetoxysilylalkoxide [(BuO)(PhCO)Si(OAc)] led to the formation of borosilicates (BuO)(PhCO)Si{(μ-O)BPh}(μ-O) (1), [{(BuO)(PhCO)Si(μ-O)BPh(μ-O)}] (2), and [{(BuO)(PhCO)Si(μ-O)B(3-HOPh)(μ-O)}] (3) with a cyclic inorganic BSiO or BSiO core, respectively. On the other hand, the reaction of phenylboronic acid with triacetoxysilylalkoxide (PhCO)Si(OAc) in 3:2 ratio resulted in the formation of a cagelike structure [{(PhCO)Si(μ-O)BPh(μ-O)}] (4) with BSiO core, while the reaction of the boronic acid with silicon tetraacetate generated an unusual 1,3-bis(acetate)-1,3-diphenyldiboraxane PhB(μ-O)(μ-O,O'-OAc)BPh (5). Additionally, compound 1 was used to evaluate the possibility to form N→B donor-acceptor bond between the boron atom in the borosilicates and a nitrogen donor. Thus, coordination of 1 with piperazine yielded a tricyclic [{(BuO)(PhCO)Si(OBPh)(μ-O)}·CHN] compound 6 with two borosilicate rings bridged by a piperazine molecule. Finally, the processes involved in the formation of the six- and eight-membered rings (BSiO and BSiO) in compounds 1 and 2 were explored using solution H NMR studies and density functional theory calculations. These molecules represent to the best of our knowledge first examples of cyclic molecular borosilicates containing SiO units.

Alumoxane and aluminum dihydrides activate CO2 producing unusual inorganic cores while reactions with CS2 produce cyclic alumoxane and aluminum sulfides.

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The 4,5‐{Ph2(HO)C}2‐1,2,3‐triazole ligand (2) with two bulky Ph2C(HO) substituents was synthesized and used in the preparation of coordination compounds with selected group 1 metals. In the solid state, the high Lewis acidity of lithium caused the formation of di‐ and tetrametallic L2Li2thf4·2THF and L4Li4thf2(Et2O)2·2Et2O (L = monoanionic form of 2) species, while only the dimetallic derivative L2Na2thf4·2THF was observed for sodium. The larger size of potassium caused the formation of L6K6(H2O)thf2·2THF with a hexagonal drumlike inorganic core. 1H DOSY NMR spectroscopic studies confirmed the presence of multimetallic species also in solution. The molecular structures of the compounds were determined by single‐crystal X‐ray diffraction. In a comparative study, magnesium derivatives of 2 were prepared to evaluate the effect of a higher covalent character of the M–O bond leading to multimetallic polycyclic systems with up to 29 rings. Finally, the lithium compounds showed catalytic activity in the polymerization of ε‐caprolactone.