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Three cadmium(II) coordination polymers, namely {[Cd(HLI)(NO3)2]·0.5MeOH}n (1), {[Cd(HLII)(NO3)2]·EtOH}n (2), and [Cd2(LII)2(NO3)2]n (3), have been self-assembled from Cd(NO3)2 and N,N′,O-pincer-type isonicotinoylhydrazone-based ditopic ligands (HLI = N′-(pyridin-2-ylmethylene)isonicotinohydrazide and HLII = N′-(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide) and have been characterized experimentally and by DFT computations. In compounds 1 and 2, the corresponding ligand is coordinated to the metal center in the keto form and acted as a tetradentate chelating–bridging agent in which the nitrogen atom of the 4-pyridine ring is coordinated to the cadmium center of the neighboring unit, yielding 1D zig-zag coordination polymers. In compound 3, the ligand was singly-deprotonated and is coordinated in the enolic form with the nitrate ion further acted as a bridging agent, yielding a 2D network. It is revealed by the extended transition state natural orbital for chemical valence (ETS-NOCV) charge and energy decomposition scheme that typical hydrogen bonds O–H⋯O and N–H⋯O, which constitute the networks of 1 and 2, though dominated by a classic Coulomb term, are characterized by an equally important London dispersion constituent due to extra π⋯π and C–H⋯X contacts (X = O, H–C, H–N). The architecture of 3 is due to ionic and dative-covalent Cd–X (X = N, O) bonds as well as London dispersion-driven homopolar dihydrogen C–H⋯H–C and C–H⋯O interactions. NOCV-based representation allowed us to determine that hydrogen bonds O–H⋯O are twice weaker than the corresponding N–H⋯O in the networks of 1 and 2. [ABSTRACT FROM AUTHOR]

The reaction of phenoxatellurine (PT) with the known single-electron oxidizers AlCl3/CH2Cl2, [NO][SbF6] and [NO][BF4] provided the diamagnetic products [(PT)CH2Cl][AlCl4] (1), [PT2][SbF6]2 (2) and [PT3][BF4]2 (3), respectively, which were fully characterized by X-ray crystallography. The dications [PT2]2+ and [PT3]2+ present in 2 and 3 can be regarded as dimers of the elusive radical cation [PT]˙+ or as adduct between this dimer and neutral PT, respectively. The stacking between the aromatic layers of [PT2]2+ and [PT3]2+ can be best described using the pancake bonding (PB) model. The computational analysis uncovers the essential role of London dispersion effects for the stacking process and reveals the Te–Te interactions to be dominated by non-covalent bonding. The results are compared with those of the related thianthrene (TA) system. [ABSTRACT FROM AUTHOR]

The perfluorinated alkoxy silanes {(F3C)3CO}3SiH (1) and {(F5C6)3CO}2Si(Cl)H (2) were prepared and fully characterized. Despite the high calculated Brønsted acidities, all attempts to deprotonate 1 and 2 to give the conjugate silanide ions failed due to the exceptionally short and strong Si–H bonds. In the solid state, the Si–H units are not involved in any intermolecular interactions, but instead the crystal packing consists of exceptionally short and strong F⋯F interactions. The cohesive energies are entirely comprised of London dispersion interactions, similarly as in the crystal structures of noble gases. [ABSTRACT FROM AUTHOR]