Heavy Group 15 Element Pacman Complexes

Calix[4]pyrrole macrocycles (Pacman ligands) were used to incorporate heavy pnictogens (As, Sb, and Bi), yielding halogeno-pnictogen complexes ( Pac(EX) 2, E = As, Sb, Bi; X = Cl, I). Arsenic(III) chloro complex Pac(AsCl) 2 was synthesized in solution and isolated, while arsenic(III), antimony(III), and bismuth(III) complexes ( Pac(AsI) 2, Pac(SbCl) 2, Pac(BiCl) 2, Pac(BiI) 2 ) were formed in solution but could not be isolated. The arsenic(III) chloro complex showed temperature- and chloride-dependent dynamics similar to Pac(PCl) 2 . Hydrolysis of transient iodoarsane and chlorostibane produced oxygen-bridged complexes of the type Pac(E-O-E) . In the case of the synthesis of Pac(SbCl) 2, an intermediate, PacH 2 (SbCl 2 ) 2, was isolated and fully characterized. Through further HCl elimination, the last two HCl molecules were finally split off, resulting in the formation of Pac(SbCl) 2 . Bismuth(III) analogues were detected only transiently via 1 H NMR spectroscopy. All isolated compounds were characterized spectroscopically, crystallographically, and theoretically. Reducing Pac(EX) 2 complexes led to decomposition and not to the desired formation of biradical Pac(E · ) 2 .