A step towards low‐cost thin‐film electronics is achieved, based on the microwave‐assisted synthesis of In2O3:Sn (ITO) nanoparticles in ionic liquids (see figure). Ink‐jet printed layers of the ITO nanoparticles on plastics exhibit a high transmittance and conductivity, without the need for performing any conventional thermal post‐treatment. Significantly improved layers with higher conductivities are to be expected from high‐quality printing.

The low-pressure association reactions for the proton bound dimers of acetone and a number of deuterium substituted variants have been studied using Fourier transform ion cyclotron resonance spectrometry. The association rate constants for the reactions (CH3)2COH+ + (CH&CO, (CH&COD+ + (CH&CO, (CD3)2-COH+ + (CD&CO, and (CD&COD+ + (CD&CO have been studied as a function of pressure, and from these data the unimolecular dissociation rate constants, kb, of the intermediate chemically activated adducts as well as their radiative cooling rates, kra, were derived. The kb were measured to be in the range of (1.49-4.9) X lo4 s-I at 47 OC, corresponding to adduct lifetimes of 20-67 ~.ls. These lifetimes were strongly dependent on deuterium labeling of the acetone. The radiative rate constants, k,,, vary between 96 and 147 s-l with little influence of the deuterium labeling in the methyl groups, but a significant dependence when the dimer is bridged by H+ us D+. A decrease in the temperature of the ion cyclotron resonance cell by about 20 OC results in a decrease in kb by about a factor of 2 with only a slight decrease in kra. These results are discussed in terms of RRKM theory, statistical thermodynamics, and the mechanism of spontaneous emission of radiation from chemically activated ions.

Studies of unimolecular dissociation (MIKES) of ions formed in a chemical ionization ion source show that under CI conditions, the reaction of CH 3 + with CH 3 OH or CH 3 OCH 3 leads to the covalent structures (CH 3 ) 2 -OH + or (CH 3 ) 3 O + . In contrast a FT-ICR study indicates that these reactions lead either to covalent structures by C-O bond formation and to [CH 3 + /CH 3 OH] or [CH 3 + /CH 3 OCH 3 ] ion-neutral complexes. Ab initio calculations confirm that such complexes correspond to minima on the potential energy surface. Their geometries correspond to a species in which a hydrogen of the CH 3 + cation is weakly bonded to the oxygen of the neutral. The interaction energies are ∼20 kcal/mol.

The spatial separation of ion generation and ion detection in ICR spectrometry is known to have many advantages. The pressure in the ICR cell can be maintained at very low values, which enhances resolution and sensitivity. Furthermore, ionization techniques like CI and FAB become feasible'.Little attention has been focused on the advantages of a n external ionization concerning the study of ion-molecule reactions. Ionization of the reactant gas within the ICR cell is avoided and the temperature of the neutral gas is kept at room temperature. The most important advantage is, however, that the ions, generated in the external ion source, cannot react with their neutral precursors after transfer into the ICR cell.We have examined the reaction of NHS' ions, generated in the external ion source of a Bruker CMS 47X FT-ICR spectrometer, after transfer into the ICR cell with chlorobenzene. It can be seen from figures 1 and 2 that exclusively charge exchange occurs (reaction (l)), beside very little l o s s of a chlorine atom from chlorobenzene radical cations (m/z 112 -mlz 77).NHf' t C,H5C1m / z 17 IE = 9.07 eV2 m / z 112 IE = 10.15 eVZ

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Ionic gas-phase reactions of chloro-and bromoanisoles with CH3NH2 and (CH3)2NH via radical cations were investigated by FT-ICR spectrometry using an external ion source. Protonated N-methylanisidines are formed quantitatively from bromoanisole radical cations with CH3NH2 by ipso substitution of the bromo atom. The analogous reaction of chloroanisole radical cations produce a mixture of protonated and radical cationic N-methylanisidines, the latter ions arising by loss of HCl from the addition complex and corresponding also to ipso substitution products. The branching ratio of product ions and the reaction efficiencies depend on the structure of the haloanisole radical cations, the efficiencies ranging from 1.3% to 24%. The observed dependence of the reactivity on the substitution pattern is in good agreement with earlier results of the reactions of dihalobenzene radical cations with NH3 and shows that all substitution reactions proceed by the same multistep mechanism in which the addition of the amine to the aromatic radical cation in the collision complex is rate determining. The reactions of (CH3)2NH'+ with neutral bromoanisoles in the ICR cell produce protonated N,N-dimethylanisidines besides bromoanisole radical cations by charge exchange. Chloroanisoles produce with (CH3)2NH'+ additionally N,N-dimethylanisidine radical cations by loss of HCl. Deuterium labelling experiments reveal that the H atom eliminated with HCl originates from the amino group. The kinetic behaviour of both substitution processes indicates that branching between loss of Cl and HCl occurs after the rate determining addition step in a chemically activated intermediate. Competition of loss of Cl and by elimination of HCl is observed only for reactions of low reaction efficiencies and is apparently controlled by the excess energy of the excited intermediate adduct.

The reactions of the radical cations of the halobenzenes C6HSX'+ (X = Cl, Br, I), the isomeric dichlorobenzenes and the isomeric chloroiodobenzenes with CH,NH, as well as the reactions of the radical cations CH,NH;+ and (CH,)*NH'+ with the above neutral halobenzenes were studied by Fourier transform ion cyclotron resonance spectrometry. In all cases the substitution of a halogen substituent by R*NH+ (R = H, CH,) was observed besides charge exchange. The substitution of halobenzene radical cation by CH,NH, is always fast (the reaction efftciency (eff,,,,,) being greater than 28%) compared to the reaction with NH, studied before, but exhibits principally the same dependence on the nature and position of the halogen substituent as the latter reaction. The substitution of neutral halobenzenes, where the ionization energy of the halobenzene is greater than the ionization energy of methylamine, by CH3NH;+ is also fast (eff,,, > 50%) and is not much influenced by the structure of the halobenzene. In contrast, the rate of substitution of all halobenzenes by (CH3),NH'+ is small (e&s,, < 14%), increases with the halogen lost in the series Cl < Br < 1, and exhibits a distinct orientation effect for dihalobenzenes, the meta isomer being least reactive. These experimental results are discussed using thermochemical data from the literature and the curve crossing model of Shaik and Pross. The results are consistently rationalized for the reaction of ionized halobenzenes with neutral amines as well as the reaction of neutral halobenzenes with ionized amines by a mechanism involving addition to the aromatic system, rearrangement of the intermediate distonic ion to an ipso-substituted isomer, and dissociation of the intermediate by loss of halogen. However, the rate-determining step of this mechanism depends on the substrates involved, and this structural dependence of the reactions can be understood by the curve crossing model.

Interestingly, the efficiency of the adduct ion formation depends on the sterochemistry of ions A,'.