[Ga₅₁(PtBu₂)₁₄Br₆]³⁻: ein elementoider Galliumcluster mit metalloiden und nichtmetalloiden Strukturelementen

Abstract

ZuschriftenDie Bindungsmuster der sieben Galliummodifikationen weisen den Weg der "Weltraummoleküle" GaBr(GaR) über metalloide Galliumcluster -hier einen von GaP-Einheiten eingeschnürten, nanoskaligen [Ga 51 (PtBu 2 ) 14 Br 6 ]-Cluster -zum Metall. Näheres dazu erfahren Sie in der Zuschrift von H. Schnöckel et al. auf den folgenden Seiten.

Metastable Aluminum(I) Compounds: Experimental and Quantum Chemical Investigations on Aluminum(I) Phosphanides—An Alternative Channel to the Disproportionation Reaction?

“…For the phosphanide-substituted GaClA C H T U N G T R E N N U N G (PMe 2 ) 2 model compound, we have calculated the primary insertion step of GaCl (Scheme 3) to be exothermic by À40 kJ mol À1 . [40] Since the structure of the Ga 2 Cl 2 A C H T U N G T R E N N U N G (PMe 2 ) 2 species is analogous to that of the Ga 2 X 4 molecules and since a number of subvalent gallium phosphanide compounds, as well as metalloid clusters, have already been characterized, [12][13][14][15][16] the disproportionation process may be expected to proceed in the same manner as in the case of the binary halides.…”

“…However, in contrast to the above mentioned Al clusters, the PR 2 ligands also exhibit bridging (Ga-PR 2 -Ga) bonding. Examples of this type of cluster are Ga 16 R 10 , [12] (see below), Ga 22 R 12 , [13] Ga 18 R 10 3À , [14] and [Ga 51 Br 6 R 14 ] 3À , [15] with R = PtBu 2 .…”

A Second Metalloid Ga18 Cluster and Its Topological Similarity to the High‐Pressure Ga‐II Modification

“…For example, the central coordination polyhedra in the neutral cluster compound [Ga 22 R 12 ] (1) [2] are Ga 12 icosahedra (d-gallium) and centered Ga 13 cubeoctahedra (face-centered cubic Ga-IV) in the anionic cluster [Ga 51 R 14 Br 6 ] 3À (2). [3] By comparing the volume of the central Ga 12 or Ga 13 polyhedra in the cluster compounds 1 and 2, respectively, with the corresponding gallium modification it has been shown by quantum chemical single-point calculations that the cluster cores of 1 and 2 are "compressed"; this compression can be explained to some extent by the constricting effects of the PtBu 2 ligands (cf. below).…”

“…: In contrast to the previously used ligands, [5] for example, -NA C H T U N G T R E N N U N G (SiMe 3 ) 2 or -CA C H T U N G T R E N N U N G (SiMe 3 ) 3 , the PtBu 2 ligand is characterized by its ability to form bridging coordination modes in addition to occupying terminal positions on the cluster framework. [2,3] The number of phosphanide ligands in terminal and bridging positions is similar in the reported compounds 1 (6:6), 2 (6:8), and 3 (6:4).…”

“…We recently reported the synthesis of metalloid [1] gallium cluster compounds [2,3] in which the sterically demanding phosphanide ligands PR 2 (R = tBu 2 ) lead to structures that are analogous to modifications of elemental gallium. For example, the central coordination polyhedra in the neutral cluster compound [Ga 22 R 12 ] (1) [2] are Ga 12 icosahedra (d-gallium) and centered Ga 13 cubeoctahedra (face-centered cubic Ga-IV) in the anionic cluster [Ga 51 R 14 Br 6 ] 3À (2).…”