The Missing Parent Compound [(C5H5)Fe(η5-P5)]: Synthesis, Characterization, Coordination Behavior and Encapsulation

Abstract

The so far missing parent compound of the large family of pentaphosphaferrocenes [CpFe(η5-P5)] (1 b) was synthesized by the thermolysis of [CpFe(CO)2]2 with P4 using the very high-boiling solvent diisopropylbenzene. It was comprehensively characterized by, inter alia, NMR spectroscopy, single crystal X-ray structure analysis, cyclic voltammetry and DFT computations. Moreover, its coordination behavior towards CuI halides was explored, revealing the unprecedented 2D polymeric networks [{CpFe(η5:1:1:1:1-P5)}Cu2(μ-X)2]n (2 a: X=Cl, 2 b: X=Br) and [{CpFe(η5:1:1-P5)}Cu(μ-I)]n (3) and even the first cyclo-P5-containing 3D coordination polymer [{CpFe(η5:1:1-P5)}Cu(μ-I)]n (4). The sandwich complex 1 b can also be incorporated in nano-sized supramolecules based on [Cp*Fe(η5-P5)] (1 a) and CuX (X=Cl, Br, I): [CpFe(η5-P5)]@[{Cp*Fe(η5-P5)}12(CuX)20-n] (5 a: X=Cl, n=2.4; 5 b: X=Br, n=2.4; 5 c: X=I, n=0.95). Thereby, the formation of the CuI-containing fullerene-like sphere 5 c is found for the first time.