Salts of the ethynyl-closo-dodecaborate dianion [HCϵCcloso-B 12 H 11 ] 2-(1) were synthesized by a microwave-assisted palladium-catalyzed cross-coupling reaction starting from the iodinated cluster [I-closo-B 12 H 11 ] 2and Me 3 SiCϵCMgBr. The dianion was characterized in its [nBu 4 N] + and Cs + salt by multi-NMR and vibrational spectroscopy as well as by (-)-MALDI mass spectrometry. A crystal of [nBu 4 N] 2 [HCϵC-closo-B 12 H 11 ] was studied by X-ray dif-* Prof. Dr. M. Finze

Despite the fact that pyridinium based anion exchange membranes for alkaline fuel cells suffer from low alkaline stability due to hydroxide attack in the ortho position and the subsequent irreversible oxidation to 2-pyridone, new copolymers consisting of aromatic polyethers bearing 2,6-position protected pyridinium units as hydroxide conducting groups in the backbone, have been designed. In particular, aromatic polyethers bearing N-methyl pyridinium as functional group have been prepared by copolymerization of the corresponding 2,6-bis(4-hydroxyphenyl)pyridine or 2,6-difluoropyridine with various monomers, followed by methylation and alkalization in aqueous KOH solution. The alkaline stability was confirmed by thermal stability tests (TGA) and 1 H NMR spectroscopy. It was shown that the methylation degree plays an important role in alkaline stability; membranes with low methylation degree, e.g., the 2,6-phenyl substituted pyridinium based ones, remain remarkably stable even after 456 h in 1 M KOH solution at 60 C, whereas the homopolymer with a higher methylation degree, showed some initial degradation due to hydroxide attack in the para position during the first 168 h and then remained stable for at least additional 288 h under the same conditions. Furthermore, the choice of substituents in the 2,6-position is as well critical for pyridinium AEM stability: pyridinium based membranes bearing phenyl substituents show higher alkaline stability compared to the corresponding membranes containing oxy substituents, due to conjugation stabilization.

Different N‐alkylated derivatives of ammonioundecahydro‐closo‐dodecaborate(1–), [B12H11NH3]–, were prepared. Strategies for the introduction of one alkyl chain or two equal alkyl chains and the trisubstitution by two different alkyl chains were developed. Several of the resulting salts have low melting points and are examples of a new class of ionic liquids.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

The crystal structure of sym-trans-di-a-phenoxyhexaphenoxydiphenolatodititanium(IV), [Ti(OCbHs)4-HOCrHs]2 has been determined by Patterson and heavy-atom methods. The crystal is monoclinic, space group P21/n, with cell constants a= 10"491 (12), b= 18"409 (28), c= 13.858 (17)/~, and r= 101.54 (25) °, containing two dimeric units per cell. Refinement by full-matrix least-squares methods yielded a final R value of 0.081. The dimer, which has two titanium atoms bridged by two phenoxy groups, is located on a center of symmetry. There are three phenoxy Ti-O bond lengths: 1.789 (9), 1.842 (11), and 1.884 (10/~), a phenol Ti-O bond length of 2.200 (11)/~, and two equal phenoxy Ti-O bridging distances of 2.027 (10) and 2"045 (11)/~,. The Ti-O-C bond angles of 168.9 (10) and 175.1 (11) °, found for two of the phenoxy oxygen atoms, are nearly linear. A decrease in the Ti-O bond distances results in a corresponding increase in the Ti-O-C bond angles for the three phenoxy groups. Hydrogen-bonding between the axial phenol and phenoxy oxygen atoms is suggested by the short oxygen-oxygen contact distance of 2.671 (13) A, the Ti'-Ti-O bond angles of 86"7 and 75-8 °, and the dihedral angle of 1.4 ° between the two planes formed by these atoms.

An X-ray diffraction study of tetraphenoxytitanium@) monophenolate has shown the structure to be dimer of octahedrally co-ordinated alkoxytitanium molecules.