A nano-sized supramolecule beyond the fullerene topology

Abstract

The reaction of [Cp(Bn) Fe(η(5) -P5 )] (1) (Cp(Bn) =η(5) -C5 (CH2 Ph)5 ) with CuI selectively yields a novel spherical supramolecule (CH2 Cl2 )3.4 @[(Cp(Bn) FeP5 )12 {CuI}54 (MeCN)1.46 ] (2) showing a linkage of the scaffold atoms which is beyond the Fullerene topology. Its extended CuI framework reveals an outer diameter of 3.7 nm-a size that has not been reached before using five-fold symmetric building blocks. Furthermore, 2 shows a remarkable solubility in CH2 Cl2 , and NMR spectroscopy reveals that the scaffold of the supramolecule remains intact in solution. In addition, a novel 2D polymer [{Cp(Bn) Fe(η(5) -P5 )}2 {Cu6 (μ-I)2 (μ3 -I)4 }]n (3) with an uncommon structural motif was isolated. Its formation can be avoided by using a large excess of CuI in the reaction with 1.

Keywords: Cp ligands; copper; phosphorus; self-assembly; supramolecular chemistry.

Figure 1

Examples of spherical supramolecules with fullerene-like topology self-assembled by 1 a and CuX (X=Cl, Br; incorporated templates are not shown). Left: 80-vertex ball, right: 90-vertex ball.

Figure 2

a) A combination of six (Cp^BnFeP₅)₂(CuX)(Cu₂I)₄ (X=I, MeCN) building blocks and eight CuI₄ tetrahedra gives the idealized scaffold (Cp^BnFeP₅)₁₂Cu₆₂I₅₈(MeCN)₄. b) One of the supramolecules in 2. Hydrogen atoms are omitted for clarity. c) The idealized scaffold of 2. d) The irreducible scaffold of 2.

Figure 3

Section of the polymeric network of 3. Cp^Bn ligands are omitted for clarity. Selected bond lengths [Å]: Cu-I 2.5764(14)–2.7920(17), Cu-P 2.262(3)–2.301(3), P-P 2.099(3)–2.117(3) and Fe-P 2.363(3)–2.426(3).