posted on 2023-11-07, 16:46authored byMarkus Freiberger, Stefan Frühwald, Martin B. Minameyer, Andreas Görling, Thomas Drewello
The supramolecular
chemistry of cycloparaphenylenes (CPPs) is characterized
by the ability of the ring system to undergo both concave and convex
π–π interactions. As a consequence, ring-in-ring
complexes can be formed in which the CPP serves as the host as well
as the guest molecule ([n + x]CPP⊃[n]CPP). In this work, host–guest ring-in-ring complexes
of [n]CPPs (n = 5–12) are
investigated by means of electrospray ionization-tandem mass spectrometry
(ESI-MS2) and laser desorption ionization mass spectrometry
(LDI-MS). Extending the experimentally known complexes with ring size
differences of five and six phenyl units (x = 5 and
6), we observe complexes with ring size differences of three up to
seven phenyl units (x = 3–7). Energy-resolved
collision experiments reveal that the charge is mainly located at
the inner ring and complexes with phenyl unit differences of five
and six are the most stable. In complexes featuring the same size
difference, the complex stabilities slightly increase with an increasing
size of the involved [n]CPPs. Utilizing the π-extended
[12]carbon nanobelt ([12]CNB) as the guest also revealed an increase
in complex stability. This study paves the way for a deeper understanding
of the host–guest chemistry of CPPs.