Gallium arene complexes

From solutions of GaCl2 in hot 1,3,5-trimethylbenzene the colorless crystalline bis(arene) complex [C6H3(CH3)3]2Ga+ GaCl4 (XLVI) has been isolated (158). The structural study reveals a bent sandwich structure for the cationic moiety, as indicated schematically in Fig. 9. The tetrachlorogallate tetrahedra are once more only weakly coordinated, this time via one chlorine atom each to the Ga(I) centers of two bis(arene)gallium units, forming a chainlike coordination polymer. The steric requirement of the mesityl ligands is... 

The chemistry of arene complexes of univalent gallium, indium,... 

Borovik, A. S. Bott, S. G. Barron, A. R. Arene-Mercury Complexes Stabilized Aluminum and Gallium Chloride Synthesis and Structural Characterization. J. Am. Chem. Soc. 

Lower rim derivatization is far easier to effect and examples include alkyl-, ester-, amide-[4], pyridyl- [5] and pyrene-appended [6] systems, not to mention the more exotic species that bind gallium [7] or give a colorimetric response when complexing chiral guests [8] as shown in Figure 3.19. Further examples include oxacalix[3]arenes that form capsules [9,10], palladium cross-linked dimers [11-13] and 2 1 inclusion complexes with C6o [14,15]. Oxacalixarenes with lower rim substituents have even been incorporated into electrochemical sensors for... 

The parent oxacalix[3] arenas show little ability to bind alkali metals,however, a range of quaternary ammonium cations are attracted to the symmetric cavity. Deprotonation of the phenol moieties allows them to bind to transition metals (scandium, titanium, vanadium, rhodium, molybdenum, gold, etc.), lanthanides (lutetium. yttrium, and lanthanum), and actinides (uranium as uranyl). Oxacalix[3]arenes derivatized on the lower rim can complex gallium, mercury, and alkali metals, including sodium, in a manner reminiscent of natural transmembrane cation filters. One major use was to purify crude samples of fullerenes. The pseudo-Cs symmetry of the macrocyclic cavity is complementary to threefold symmetry elements of Cgo. which binds preferentially in... 

---