Layered Organic-Based Metal Iodide−Polyiodide with Unique Mixed-Valent Gold(I/III) Iodide Chains

We report the synthesis, optical spectrum, and crystal and electronic structures of a new organic−inorganic hybrid compound, [(p-NH3C6H4)2CH2]4 [(AuI2)(AuI4)(I2)2(I5)2Cl4], with unique mixed-valent gold(I/III) chains. The chains feature face-shared octahedral [AuIAuIIII6]2- units and are embedded within polyiodide layers. The new mixed-valent gold iodide crystallizes in the orthorhombic space group Pnnm, with a = 27.0703(2), b = 8.9363(5), c = 18.4280(1) Å, Z = 2, and exhibits an optical band gap of 0.53 eV.