An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

AbstractThe new title compound is synthesized by reaction of carbon and CaH2 in a Ca/Li flux with a molar ratio of C/CaH2/Ca/Li of 6:1:10:10 (1323 K, 2 h, slow cooling).

The reaction of carbon and CaH2 in a calcium/lithium flux mixture produces crystals of the new compound Ca2LiC3H. This phase forms with a new structure type in tetragonal space group P4/mbm (a = 6.8236(1) Å, c = 3.7518(1) Å, Z = 2, R1 = 0.0151). This is a stuffed variant of the Cs2(NH2)N3 structure, containing hydride anions in octahedral sites; the structure determination by single-crystal X-ray diffraction surprisingly allowed the hydrogen to be detected. The Ca2LiC3H structure also features the rarely seen C3(4-) carbide anion; the protolysis reaction of this compound with ammonium chloride produces C3H4. The electronic properties of Ca2LiC3H were studied by quantum-chemical calculations including band structure and electron localization function (ELF) analysis; the phase is a charge-balanced semiconductor with a calculated band gap of 0.48 eV. This is in agreement with (7)Li, (13)C, and (1)H MAS NMR data, which show resonances in the ionic region instead of the Knight shifted region. ELF analysis of the theoretical nonhydrided Ca2LiC3 structure confirms the ability of these calculations to properly locate hydrides and supports the structural model based on X-ray diffraction data.

Silica-supported oxovanadium groups were reacted in a gas-solid reaction with aniline at 175 degrees C. The reaction was clean as monitored in situ by UV-vis spectroscopy and resulted in the elimination of water as the principal product of the reaction and the disappearance of the terminal V=O stretch in the Raman spectrum. 15N MAS solid-state NMR spectroscopy showed only a single nitrogen-containing species on the surface. Proton-dephased 15N NMR showed only weak attenuation of its intensity, indicating that there are no protons directly bonded to the nitrogen. The formation of a vanadium-imido covalent bond was characterized by 51V/15N rotational echo double resonance NMR spectroscopy where the quadrupolar 51V nucleus was monitored and the spin-1/2 15N nucleus was dephased.

Aerial parts of Onoseris alata furnished five new trans-clerodanes, loliolide and a thiopheneacetylene.

Aerial parts of Centratherum punctatum Cass. ssp. punctatum from Argentina furnished goyazensolide, and three known analogs as well as isocentratherin, one known and two new analogs. (C) 1998 Elsevier Science Ltd. All rights reserved.

Bark of Polylepis australis furnished a complex mixture of triterpene acids from which, after methylation, the methyl esters of five known and two new oleananes and five known ursanes were isolated. The esters of the two new oleananes were methyl 3 beta-hydroxyolea-9(11),12-dien-28-oate and methyl 2 alpha,3 beta-hydroxy-11-oxo-olean-12-en-28-oate. (C) 1998 Elsevier Science Ltd. All rights reserved.

Aerial parts of Anthemis aetnensis furnished the guaianolides hydruntinolide A and B and a number of new analogues, two new germacradienolides, 1-beta-hydroxyarbusculin and the isofraxidin derived sesquiterpene ether 7-acetoxypectanone. (C) 1997 Elsevier Science Ltd.