(Cyclophan‐Metall)‐Komplexe: Synthese und Kristallstruktur von ([3.3]Paracyclophan)gallium(I)‐tetrabromgallat(III)

Cyclophane‐Metal Complexes: Synthesis and Crystal Structure of ([3.3]Paracyclophane)gallium(I) Tetrabromogallate(III) [3.3]Paracyclophane forms 1:1 complexes 2a and 2b with both Ga[GaCl₄] and Ga[GaBr₄]. The crystalline products obtained from toluene solution at room temperature are much less sensitive to air and moisture than most other arene complexes of Ga(I). Solubilities in standard organic solvents are very low, suggesting coordination polymers. The X‐ray diffraction analysis of 2b confirms the presence of a two‐dimensional network. Both aromatic rings of each cyclophane molecule are η⁶‐coordinated from the outer side to Ga(I)‐atoms. The position of these metal cations is 2.75 Å above the ring centres. The arene rings are parallel within each cyclophane, but tilted by 48.5° with respect to those of the neighbouring cyclophane. The coordination sphere of the Ga(I) centres is completed by two Br‐atoms of two GaBr 4− anions, which link the Ga(I) cations to give … Ga[GaBr₄] Ga[GaBr₄]Ga … strands. The double interconnection of the Ga(I)‐atoms gives rise to a two‐dimensional sheet structure, which is thus different from the structure of the previously described Ga[GaBr₄] complex of [2.2]paracyclophane, where a three‐dimensional network was observed.