Figure 3.

Molecular model of M1 ⊃ S3 (squaraine and macrocycle alkyl groups removed for clarity), calculated by the semiempirical method at PM7 level, showing the encapsulated squaraine in a trans conformation and ends of the squaraine’s thienothiophene units outside the shielding zone of M1. (left) front view, (right) side view. Hydrogen bonds between macrocycle NH residues and squaraine oxygen atoms are indicated by green lines. Color code for atoms: grey = carbon, blue = hydrogen, blue = nitrogen, red = oxygen, yellow = sulfur.