Charging OBO‐Fused Double [5]Helicene with Electrons

Abstract

Chemical reduction of OBO-fused double-[5]helicene with Group 1m etals (Na and K) has been investigated for the first time.T wo doubly-reduced products have been isolated and structurally characterized by singlecrystal X-ray diffraction, revealing as olvent-separated ion triplet (SSIT) with Na + ions and acontact-ion pair (CIP) with K + ion. As the key structural outcome,t he X-ray crystallographic analysis discloses the consequences of adding two electrons to the double helicene core in the SSIT without metal binding and reveals the preferential binding site in the CIP with K + counterions.Inboth products,anincrease in the twisting of the double helicene core upon charging was observed. The negative charge localization at the central core has been identified by theoretical calculations,w hicha re in full agreement with X-ray crystallographic and NMR spectroscopic results.N otably,i tw as confirmed that the two-electron reduction of OBO-fused double[5]helicene is reversible. Scheme 1. Chemical reduction of OBO-fusedd ouble [5]helicene 1 with Na and Km etals to afford the reduced products 2 and 3.

Stretching [8]cycloparaphenylene with encapsulated potassium cations: structural and theoretical insights into core perturbation upon four-fold reduction and complexation

“…Similarly, each K + ion has two coordinated THF molecules (K/O THF , 2.687(8) and 2.699(9)Å), with all K/C and K/O distances being comparable to those previously reported. 8,62,63,66,67 In the solid-state structure of 2, additional K/C contacts (3.102(11)-3.309(11)Å) are found between the external K + ions and the exterior p-surface of the adjacent 1 4anions (Fig. 2).…”

Structural deformation and host–guest properties of doubly-reduced cycloparaphenylenes, [n]CPPs2− (n = 6, 8, 10, and 12)

“…Each K + ion is fully wrapped by two benzo-15-crown-5 ether molecules with the K/O crown distances (2.752(2)-2.945(2) A) being comparable to those previously reported. [51][52][53][55][56][57][58] Seven interstitial THF molecules are found to ll the structural voids with no close contacts.…”

Chemical Reduction of a Nanosized [6]Cyclo‐2,7‐naphthylene Macrocycle

“…Moreover, charging non-planar PAHs with electrons along with investigation of their electronic and structural responses [10] showed that redox processes are topology-and charge-dependent. Extensive Xray diffraction studies of electron transfer for carbon bowls, [11] belts, [12] wires, [13] and helicenes [14] revealed unusual reactivity, unique metal binding and remarkable supramolecular assem-bly patterns of the negatively charged p-systems, thus prompting a broad exploration of novel curved nanocarbon frameworks.…”