Search for: All records

Abstract Chiral organic molecules possessing high quantum yields, circular dichroism, and circularly polarized luminescence values have great potential as optically active materials for future applications. Recently, the identification of a promising class of inherently chiral compounds was reported, namely macrocyclic 1,3‐butadiyne‐linked pseudo‐meta[2.2]paracyclophanes, displaying high circular dichroism and related g_absvalues albeit modest quantum yields. Increasing the quantum yields in an attempt to get bright circularly polarized light emitters, the high‐yielding heterocyclization of those 1,3‐butadiyne bridges resulting in macrocyclic 2,5‐thienyls‐linked pseudo‐meta[2.2]paracyclophanes is herein described. The chiroptical properties of both, the previously reported 1,3‐butadiyne, and the novel 2,5‐thienyl bridged macrocycles of various sizes, are experimentally recorded, and theoretically described using density‐functional theory. 

Abstract The coordination sphere of the Fe(II) terpyridine complex1is rigidified by fourfold interlinking of both terpyridine ligands. Profiting from an octa‐aldehyde precursor complex, the ideal dimensions of the interlinking structures are determined by reversible Schiff‐base formation, before irreversible Wittig olefination provided the rigidified complex. Reversed‐phase HPLC enables the isolation of the all‐transisomer of the Fe(II) terpyridine complex1, which is fully characterized. While temperature independent low‐spin states were recorded with superconducting quantum interference device (SQUID) measurements for both, the open precursor8and the interlinked complex1, evidence of the increased rigidity of the ligand sphere in1was provided by proton T₂relaxation NMR experiments. The ligand sphere fixation in the macrocyclized complex1even reaches a level resisting substantial deformation upon deposition on an Au(111) surface, as demonstrated by its pristine form in a low temperature ultra‐high vacuum scanning tunneling microscope experiment.