Structural Development of Free or Coordinated 4′‐(4‐Pyridyl)‐2,2′:6′,2′′‐terpyridine Ligands through N‐Alkylation: New Strategies for Metallamacrocycle Formation

A series of N‐alkylated derivatives of [Ru(pytpy) 2 ] 2+ (pytpy=4′‐(4‐pyridyl)‐2,2′:6′,2′′‐terpyridine) has been synthesised and characterised. These include both model and functionalised complexes that complement previously reported iron( II ) analogues. Reaction of [Ru(pytpy) 2 ] 2+ with bis[4‐(bromomethyl)phenyl]methane leads to the formation of a [2+2] ruthenamacrocycle. Related ferramacrocycles could not be accessed by this route, and instead were prepared in two steps by first reacting bis[4‐(bromomethyl)phenyl]methane or 4,4′‐bis(bromomethyl)biphenyl with two equivalents of pytpy, and then treating the resulting bis(N‐alkylated) product with iron( II ) salts.