867171-00-4Relevant articles and documents
Aluminacyclopropene: Syntheses, characterization, and reactivity toward terminal alkynes
Zhu, Hongping,Oswald, Rainer B.,Fan, Hongjun,Roesky, Herbert W.,Ma, Qingjun,Yang, Zhi,Schmidt, Hans-Georg,Noltemeyer, Mathias,Starke, Kerstin,Hosmane, Narayan S.
, p. 5100 - 5108 (2007/10/03)
Reactions of LAl with ethyne, mono- and disubstituted alkynes, and diyne to aluminacyclopropene LAl[η2-C2(R1)(R 2)] ((L = HC[(CMe)(NAr)]2, Ar = 2,6-iPr2C 6H3); R1 = R2 = H, (1); R 1 = H, R2 = Ph, (2); R1 = R2 = Me, (3); R1 = SiMe3, R2 = C≡CSiMe 3, (4)) are reported. Compounds 1 and 2 were obtained in equimolar quantities of the starting materials at low temperature. The amount of C 2H2 was controlled by removing an excess of C 2H2 in the range from -78 to -50 °C. Compound 4 can be alternatively prepared by the substitution reaction of LAl[η2- C2(SiMe3)2] with Me 3SiC≡CC≡CSiMe3 or by the reductive coupling reaction of LAlI2 with potassium in the presence of Me 3SiC≡CC≡CSiMe3. The reaction of LAl with excess C2H2 and PhC≡CH (2)(C≡CH) (5) and LAl(CH=CHPh)(C≡CPh) (6). The reaction of LAl(η2- C2Ph2) with C2H2 and PhC≡CH yielded LAl(CPh=CHPh)(C≡CH) (7) and LAl(CPh=CHPh)(C≡CPh) (8), respectively. Rationally, the formation of 5 (or 6) may proceed through the corresponding precursor 1 (or 2). The theoretical studies based on DFT calculations show that an interaction between the Al(I) center and the C≡C unit needs almost no activation energy. Within the AlC2 ring the computational Al-C bond order of ca. 1 suggests an Al-C σ bond and therefore less π electron delocalization over the AlC2 ring. The computed Al-η2-C2 bond dissociation energies (155-82.6 kJ/mol) indicate a remarkable reactivity of aluminacyclopropene species. Finally, the 1H NMR spectroscopy monitored reaction of LAl(η2-C2Ph2) and PhC≡CH in toluene-d8 may reveal an acetylenic hydrogen migration process.
Chemistry of aluminium(I)
Roesky, Herbert W.,Kumar, S. Shravan
, p. 4027 - 4038 (2007/10/03)
In this article, we discuss the synthesis of tetrameric and monomeric aluminium(I) compounds. These compounds are prepared by reduction of the respective Al-X (X = halide) bond containing precursor. The tetrameric aluminium(I) compounds are synthesized by using sterically bulky ligands whereas a stable monomeric aluminium(I) compound is obtained using a monovalent chelating ligand. Theoretical studies are carried out on the monomer to understand the Lewis basicity. The presence of a lone pair of electrons plays an important role in the preparation of aluminium containing heterocyclic compounds, main group-main group and transition metal-main group compounds having donor-acceptor bonds by carrying out reactions with unsaturated compounds and Lewis acids. The Royal Society of Chemistry 2005.
