A large increase in the melting temperature of complementary oligonucleotides was obtained through the conjugation of terpyridine ligands at their nearby 5′ or 3′ ends and the addition of stoichiometric amounts of various transition metals. We describe here a short efficient synthetic route for the conjugation of terpyridine moieties and report new data on the stabilizing contribution of metal-assisted hybridization of oligonucleotides through UV-monitored melting temperature experiments.Résumé : Une augmentation importante de la température de fusion d'oligonucléotides complémentaires peut être obtenue par la conjugaison des ligands terpyridine à leurs extrémités adjacentes (5′ ou 3′) et l'addition de quantités stoechiométriques de divers métaux de transition. On décrit ici une courte voie de synthèse efficace pour la conjugaison des groupes terpyridine. On présente également de nouvelles données expérimentales sur l'effet stabilisant des métaux dans l'hybridation des oligonucléotides par des mesures de température de fusion soumises en spectroscopie UV.

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A new strategy to cyclize short synthetic oligonucleotides on DNA or RNA target strands is described. The approach is based on metal‐templated cyclization of short synthetic oligonucleotides conjugated with two chelating 2,2′ : 6′,2′′‐terpyridine (Tpy) moieties at their 3′‐ and 5′‐ends. Cyclization after metal addition (Zn2+, Fe2+) was demonstrated by means of thermal‐denaturation experiments, MALDI‐Q‐TOF‐MS, and gel electrophoresis (PAGE). 1D‐ and 2D‐NMR Experiments were performed to analyze the association of complementary strands after metal‐mediated cyclization. Our protocol allows the efficient circularization of synthetic oligonucleotides. Thereby, the hybridization on a complementary strand was more efficient with an RNA target strand and a 2′‐O‐methylated circularized oligomer.