Synthesis, characterization, and heparin-binding study of a self-assembled -cymene-Ru() metallocycle based on a 4-amino-1,8-naphthalimide Tröger's base supramolecular scaffold

• Published in: Dalton transactions : an international journal of inorganic chemistry 2023-02, Vol.52 (9), p.2566-257
• Main Authors: Mohan, Binduja, Shanmugaraju, Sankarasekaran
• Format: Article
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d2dt03079a

We report the very first example of a self-assembled p -cymene-Ru( ii ) metallocycle based on a green emitting 4-amino-1,8-naphthalimide Tröger's base ( TBNap ) supramolecular scaffold. A new cleft-shaped TBNap-derived di-4-picolyl donor was synthesized and reacted in a 2 : 2 stoichiometry ratio with a dinuclear Ru( ii ) acceptor ( Ru-A ) to generate a [2 + 2] self-assembled metallocycle ( TBNap-Ru-MC ) in good yield. Both TBNap and TBNap-Ru-MC showed positive solvatochromism in different solvents with varying polarities. In addition, the binding propensity of cationic TBNap-Ru-MC toward the heparin polyanion was determined using fluorescence titration studies. The initial fluorescence emission of TBNap-Ru-MC was quenched upon the gradual addition of the heparin polyanion, and the Stern-Volmer quenching constant ( K SV ) was calculated to be 3.97 × 10 5 M −1 . The synthesis, photophysics, and heparin-binding ability of a [2 + 2] self-assembled Ru( ii ) metallocycle ( TBNap-Ru-MC ) based on a green-emitting 4-amino-1,8-naphthalimide Tröger's base ( TBNap ) are described.