Synthesis and Reactivity of a Tetragallium Macrocycle

The reaction of GaCl 3 with 1,8-bis(trimethylstannyl)biphenylene produces the tetragallium macrocycle (C 12 H 6 ) 4 Ga 4 Cl 4 ( 1 ) in high yield. Compound 1 contains a cyclic array of four Ga(biphenylene) units that form a 20-membered ring. The Ga atoms are bridged by μ 2 -Cl atoms so that the Ga atoms are four-coordinate. The structure adopts a saddle-shaped conformation with approximate D 2 d symmetry. 1 reacts with Lewis bases (CH 3 CN and THF) and halide ions (Cl − and Br − ) to form (C 12 H 6 ) 2 Ga 2 Cl 2 L and (C 12 H 6 ) 2 Ga 2 Cl 2 X − species.