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(i) In the "Abstract" section Erratum "⋯RCNX (X = H+, alkaline, Lewis acids)". Corrigendum "⋯RCNX (X = H+, Lewis acids)". (ii) In the "Introduction" section Reference 6b, instead of reference 1, must be cited at the end of this sentence. Erratum "The explanation of this behavior based solely on the s/p donation/backdonation orbital interaction model discussed earlier, would imply the lack of any N ← Pt π back-donation, or at least the occurrence of such interaction which cannot overcome the effect of the N → Pt σ donation".1 Corrigendum "The explanation of this behavior based solely on the σ/π donation/backdonation orbital interaction model discussed earlier, would imply the lack of any N ← Pt π back-donation, or at least the occurrence of such interaction which cannot overcome the effect of the N → Pt σ donation".6b (iii) In the "EDA-NOCV analysis" section Erratum "The results are given in Table 4 and indicate that the total N ← Pt π back-donation represents about 30% of the total ΔEOrb term and ranges from 32% to 37% with respect to the N → Pt σ interaction which means that the orbital interaction⋯" Corrigendum "The results are given in Table 4 and indicate that the total N → Pt π back-donation represents about 30% of the total ΔEOrb term and ranges from 32% to 37% with respect to the total N-Pt σ + π interactions which means that the orbital interaction⋯" (iv) In the (a) "Infrared properties of the CN bond" and (b) "Conclusion" sections Reference 24 in the following sentences should be replaced by ref.19, i.e.: (a) Erratum "These results indicate that the νCuN blue-shift in these complexes is not correlated to the CuN bond strength, in agreement with what is already reported for some Pt(II,IV)N systems, including the herein investigated trans-1".24 Corrigendum "These results indicate that the νCuN blue-shift in these complexes is not correlated to the CuN bond strength, in agreement with what is already reported for some Pt(II,IV)N systems, including the herein investigated trans-1".19 (b) Erratum "In this context, EDA-NOCV further confirmed that the νCuN was not correlated to the CuN bond strength as already previously found".24 Corrigendum "In this context, EDA-NOCV further confirmed that the νCuN was not correlated to the CuN bond strength as already previously found".19 The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

(i) In the "Abstract" section Erratum "⋯RCNX (X = H+, alkaline, Lewis acids)". Corrigendum "⋯RCNX (X = H+, Lewis acids)". (ii) In the "Introduction" section Reference 6b, instead of reference 1, must be cited at the end of this sentence. Erratum "The explanation of this behavior based solely on the s/p donation/backdonation orbital interaction model discussed earlier, would imply the lack of any N ← Pt π back-donation, or at least the occurrence of such interaction which cannot overcome the effect of the N → Pt σ donation".1 Corrigendum "The explanation of this behavior based solely on the σ/π donation/backdonation orbital interaction model discussed earlier, would imply the lack of any N ← Pt π back-donation, or at least the occurrence of such interaction which cannot overcome the effect of the N → Pt σ donation".6b (iii) In the "EDA-NOCV analysis" section Erratum "The results are given in Table 4 and indicate that the total N ← Pt π back-donation represents about 30% of the total ΔEOrb term and ranges from 32% to 37% with respect to the N → Pt σ interaction which means that the orbital interaction⋯" Corrigendum "The results are given in Table 4 and indicate that the total N → Pt π back-donation represents about 30% of the total ΔEOrb term and ranges from 32% to 37% with respect to the total N-Pt σ + π interactions which means that the orbital interaction⋯" (iv) In the (a) "Infrared properties of the CN bond" and (b) "Conclusion" sections Reference 24 in the following sentences should be replaced by ref.19, i.e.: (a) Erratum "These results indicate that the νCuN blue-shift in these complexes is not correlated to the CuN bond strength, in agreement with what is already reported for some Pt(II,IV)N systems, including the herein investigated trans-1".24 Corrigendum "These results indicate that the νCuN blue-shift in these complexes is not correlated to the CuN bond strength, in agreement with what is already reported for some Pt(II,IV)N systems, including the herein investigated trans-1".19 (b) Erratum "In this context, EDA-NOCV further confirmed that the νCuN was not correlated to the CuN bond strength as already previously found".24 Corrigendum "In this context, EDA-NOCV further confirmed that the νCuN was not correlated to the CuN bond strength as already previously found".19 The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

A ZSM-5 fragment, containing 52 tetrahedral moieties, each of them formed by one silicon or one aluminum atom surrounded by four oxygen atoms, was employed to model (52T systems) by quantum chemical calculations (i) the influence of the positions of the acidic sites on the energetics of 22 aluminum monosubstituted and bisubstituted 52T acidic zeolite (H-ZSM-5) systems and (ii) the local adsorption properties and acidic strength of the corresponding -OH sites. The energetics and the structural properties of simpler acid H-ZSM-5 systems containing only five Tetrahedral moieties (5T systems) were also modeled for comparison. B3LYP/6-31G(d,p) partial geometry optimization routines were performed on the 5T and 52T systems. On the latter, ONIOM(B3LYP/6-31G(d,p)jAM1) calculations and an alternative approach, i.e., the ONIOM method followed by a single-point at the above B3LYP/6-31G(d,p) level, aimed to decrease the need of computational resources, were also employed to analyze the properties of the different H-ZSM-5 models. The whole results showed that the orientation and the position of the acidic hydrogen atoms within the zeolite channel strongly affect the stability of the model systems, irrespective of the starting local topology characterizing the Al T Si substitution site. Bro¨nsted gas-phase acidity strength and adsorption-ability were evaluated through the analysis of the energy involved in (i) the proton dissociation from the acidic sites and (ii) the cis-but-2-ene and trans-but-2-ene adsorption on the same acidic sites. Both were affected, although to a very different extent, by the location and number of the considered -OH acidic groups. In particular, 2 among the 12 modeled acidic sites resulted in a highly stabilized zeolite structure, pointing out that the Al T Si substitutions in the synthesis of aluminated ZSM-5 zeolites, and hence the corresponding catalytic activity, could preferentially occur on special sites. The choice of the computational method along with the size and the cutoff of the mimicked structures influenced the reliability of the calculations. The suggested alternative approach (that is, the ONIOM followed by the DFT single-point calculation) provided reasonable findings at very low computational cost.

Our group has a long researching tradition in the field of organotin(IV) complexes, usually proposed and tested as potential anti-tumor drugs. The leitmotif has usually been the modulation of the intrinsic toxicity/cytotoxicity of the organometallic moiety and a modulation of the toxic effect by means of biologically related molecules (synthetic or natural). Such a modulation is usually achieved by two (often overlapping) routes: dampen the damaging effects of the metal core, and serving as a carrier for specific tissue districts. Since a too tight binding on the organotin moiety is not always desirable – a too much stable complex could be a non-active one – carboxylates have always played an important role in our research, as attested by many papers. In the past, the carboxylic function has been used as an anchor for the tin, leaving to other functional groups the “biological” tasks; in this work, though, is directed towards some simple – aliphatic chain, no other functional (coordinating) groups – carboxylic acids, such as butyric or valproic acid. Even in their simplicity, those acids were chosen because of their anion activity as histone deacetylase inhibitors, and, as such, are used as adjunct in cancer treatment. Similarly to other previously studied simple acids (unpublished results), a large difference occurs in di- and tri-organo compounds, but in a constant pattern. This presentation deals with some preliminary structural characterization and biological assays.

The acetylation status of histones is regulated in eukaryotes by two kinds of enzymes, histone acetyltransferases (HATs) and histone deacetylases (HDACs), which are responsible for acetylation and deacetylation of lysines residues in N-terminal tails of histone.[1] Thus acetylation, together with phosphorylation and methylation of N-terminal tail of histones, are involved in regulating fundamental processes, such as proliferation and cell death.[2-3] Sodium butyrate, which belongs together with valproic acid to the class of short chain fatty acids, was the first HDAC inhibitor (HDACI) to be identified.[1] Organotin compounds have various influences on physical function including the hormone and immune systems, embryogenesis, and development. Dibutyltin and diphenyltin, metabolites of TBT and TPT, respectively, also promoted HAT activity.[4] New triorganotin(IV) complexes of valproic acid have been synthesized and investigated by spectroscopical and biological methods. An anionic, monodentate valproate ligand was observed, ester-like coordinating the tin atom on a tetra-coordinated, monomeric environment. The structures, though, can distort towards a pentacoordination, as a consequence of a long range O-Sn interaction. Crystallographic and NMR findings confirm this situation both in solid state and solution. Biological finding evidenced a clear cytotoxic action of the complexes in hepatocellular carcinoma cell cultures: one of the complexes induced an 80% cell viability reduction after 24 h treatment in HepG2 cells. This effect was accompanied by the appearance of biochemical signs of apoptosis. In Chang liver cells, the same compound induced only modest effects, suggesting a potential use as anti-cancer drug.