In focused electron beam induced deposition (FEBID) acetylacetone plays a role as a ligand in metal acetylacetonate complexes. As part of a larger effort to understand the chemical processes in FEBID, the electron-induced reactions of acetylacetone were studied both in condensed layers and in the gas phase and compared to those of acetone. X-ray photoelectron spectroscopy (XPS) shows that the electron-induced decomposition of condensed acetone layers yields a non-volatile hydrocarbon residue while electron irradiation of acetylacetone films produces a non-volatile residue that contains not only much larger amounts of carbon but also significant amounts of oxygen. Electron-stimulated desorption (ESD) and thermal desorption spectrometry (TDS) measurements reveal striking differences in the decay kinetics of the layers. In particular, intact acetylacetone suppresses the desorption of volatile products. Gas-phase studies of dissociative electron attachment and electron impact ionization suggest that this effect cannot be traced back to differences in the initial fragmentation reactions of the isolated molecules but is due to subsequent dissociation processes and to an efficient reaction of released methyl radicals with adjacent acetylacetone molecules. These results could explain the incorporation of large amounts of ligand material in deposits fabricated by FEBID processes using acetylacetonate complexes.

•Acylation of alcohols with acryloyl chloride in the presence of pyridine fails due to the β-addition of pyridine.•Three types of pyridinium derivatives were identified in the reaction mixture.•The mechanism of the reactions was explored using NMR and MS.•Simple synthetic approaches are now available to prepare various pyridinium derivatives.Direct acylation reactions of alcohols with acid chlorides in the presence of pyridine leads to the formation of unexpected pyridinium derivatives as major products. Although this phenomenon was briefly reported several decades ago, a detailed structure elucidation of the intermediates and ionic products was missing. In this study, the formed pyridinium products are structurally characterized and the underlying reaction mechanism is discussed. The addition of reactants in the order acryloyl chloride—R-OH—pyridine yields a structure P1, which was tentatively proposed before. However, if the order of reactant addition was changed, that is, R-OH was added to a mixture of acryloyl chloride and pyridine, two new types of pyridinium derivatives (P2 and P3) were observed. Their formation implies the unprecedented β-addition of pyridine to acryloyl chloride followed by a Michael addition of the nucleophilic α-carbon or by an alkylation of the activated carboxyl group. The proposed reaction mechanism is supported by a detailed structural analysis of intermediates and products.

•We study the cage opening of the periodinated closo-dodecaborate B12I122− upon deiodination.•We report infrared photodissociation spectra combined with electronic structure calculations.•Quasi-icosahedral cage structures absorb exclusively below 975 cm−1.•Breakup of the cage structure is signaled by IR activity above 1000 cm−1.•Cage opening occurs in-between B12I8− and B12I7−.The opening of an icosahderal boron cage in the periodinated closo-dodecaborate B12I122− upon deiodination is studied using cryogenic ion trap vibrational spectroscopy combined with electronic structure calculations. Comparison of simulated vibrational spectra to the infrared photodissociation spectra of messenger-tagged B12I122− and B12In− (n = 7–9) formed by skimmer collision induced dissociation shows that the larger clusters absorb exclusively below 975 cm−1 and hence exhibit quasi-icosahedral B12-cage structures, while the higher energy absorptions in-between 1000 and 1300 cm−1 observed for n = 7 can only be recovered by considering a breakup of the icosahedral cage upon deiodination from n = 8 to n = 7.

Salts of the mercury(II) complexes [Hg(closo-1-CB11X11)2]2– (X = H (1), Cl (3), Br (4)) and [PhHg(closo-1-CB11X11)]− (X = H (6), Cl (8), Br (9), I (10)) were synthesized and characterized by multi-NMR spectroscopy, mass spectrometry, elemental analysis, and differential scanning calorimetry. Single crystals of Cs21·2Et2O, Cs23·MeCN, Cs24·4Me2CO, Cs9, and [Et4N]6·0.5Me2CO were studied by X-ray diffraction, and the interpretation of the bond properties is supported by theoretical data. In contrast to the mercury atom of the previously published [Hg(closo-1-CB11F11)2]2– (2), which coordinates either acetonitrile or water, the metal atom of the related dianionic complexes 1, 3, and 4 does not reveal any further coordination. According to results derived from DFT and ab initio calculations, this different behavior is reasoned in the case of 1 by a reduced Lewis acidity at mercury and in the case of 3 and 4 by the increased shielding of the central mercury atom as a result of the bulky halogenated carba-closo-dodecaboranyl ligands [closo-1-CB11X11]2– (X = Cl, Br). The dianionic complex [Hg(closo-1-CB11I11)2]2– (5) with the bulkiest carba-closo-dodecaboranyl ligand was generated via collision-induced dissociation and characterized by (−)-ESI mass spectrometry. The fragmentation pathways of the anionic complexes [Hg(closo-1-CB11X11)2]2– (X = H, F, Cl, Br, I (1–5)) and [PhHg(closo-1-CB11X11)]− (X = H, F, Cl, Br, I (6–10)) were studied by (−)-ESI mass spectrometry.

In focused electron beam induced deposition (FEBID) acetylacetone plays a role as a ligand in metal acetylacetonate complexes. As part of a larger effort to understand the chemical processes in FEBID, the electron-induced reactions of acetylacetone were studied both in condensed layers and in the gas phase and compared to those of acetone. X-ray photoelectron spectroscopy (XPS) shows that the electron-induced decomposition of condensed acetone layers yields a non-volatile hydrocarbon residue while electron irradiation of acetylacetone films produces a non-volatile residue that contains not only much larger amounts of carbon but also significant amounts of oxygen. Electron-stimulated desorption (ESD) and thermal desorption spectrometry (TDS) measurements reveal striking differences in the decay kinetics of the layers. In particular, intact acetylacetone suppresses the desorption of volatile products. Gas-phase studies of dissociative electron attachment and electron impact ionization suggest that this effect cannot be traced back to differences in the initial fragmentation reactions of the isolated molecules but is due to subsequent dissociation processes and to an efficient reaction of released methyl radicals with adjacent acetylacetone molecules. These results could explain the incorporation of large amounts of ligand material in deposits fabricated by FEBID processes using acetylacetonate complexes.