Facile Synthesis of 2,9‐Diamino‐1,10‐Phenanthrolines, 2,9‐Difluoro‐1,10‐Phenanthrolines and Soluble Bis‐Phenanthroline‐Macrocycles

Reactions of 2,9‐dichloro‐1,10‐phenanthroline and its 4,5‐substituted derivatives with the ammonia surrogate p ‐methoxybenzylamine produce the corresponding mono‐ or diamino phenanthrolines in excellent yields following deprotection. Metathesis of various 2,9‐dichloro‐1,10‐phenanthrolines with anhydrous NMe ₄ F yields the respective 2,9‐difluoro‐1,10‐phenanthrolines in up to 94% yield. Condensation of 2,9‐diamino‐1,10‐phenanthroline with various 2,9‐difluoro‐1,10‐phenanthrolines affords nitrogen‐bridged bis‐phenanthroline macrocycles in 59%–80% yield. Macrocycles bearing 4,5‐(OBu) ₂ substituents and their respective metal complexes exhibit high solubility in common organic solvents, enabling detailed solution‐state spectroscopic and electrochemical studies.