Three-Component Self-Assembly Changes its Course: A Leap from Simple Polymers to 3D Networks of Spherical Host-Guest Assemblies

Abstract

One-pot self-assembly reactions of the polyphosphorus complex [Cp*Fe(η⁵ -P₅ )] (A), a coinage metal salt AgSbF₆ , and flexible aliphatic dinitriles NC(CH₂ )_x CN (x=1-10) yield 1D, 2D, and 3D coordination polymers. The seven-membered backbone of the dinitrile was experimentally found as the borderline for the self-assembly system furnishing products of different kinds. At x<7, various rather simple polymers are exclusively formed possessing either 0D or 1D Ag/A structural motifs connected by dinitrile spacers, while at x≥7, the self-assembly switches to unprecedented extraordinary 3D networks of nano-sized host-guest assemblies (SbF₆ )@[(A)₉ Ag₁₁ ]¹¹⁺ (x=7) or (A)@[(A)₁₂ Ag₁₂ ]¹²⁺ (x=8-10) linked by dinitriles. The polycationic nodes represent the first superspheres based on A and silver and are host-guest able. All products are characterized by NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. The assemblies [(A)₁₂ Ag₁₂ ]¹²⁺ were visualized by transmission electron microscopy.

Keywords: coordination networks; flexible linkers; metallosupramolecular chemistry; pentaphosphaferrocene; supramolecules.