The 4-pyridonyl group as a multifunctional electron donor in 1,8-naphthalimide-based photoluminescent and mechanically interlocked coordination compounds

Hawes, Chris S.

Abstract

A new ligand system incorporating the 4-pyridonyl group as a substituent in 1,8-naphthalimide compounds is presented, with the pyridone group acting as both an electron donor for the internal charge transfer (ICT) fluoresence process and as a metal binding moiety. After establishing the solution-state photophysical properties of the new pyridyl and carboxyphenyl derivatives L1 and HL2, respectively, we have prepared and characterised four crystalline d¬-block metal complexes containing the 4-(4-pyridonyl)-1,8-naphthalimide residue. Complex 1, a discrete mononuclear Ag(I) complex, and complexes 2 and 3, both one-dimensional Zn(II) coordination polymers, all exhibit striking photoluminescence in the crystalline phase, the nature of which can be related to the solid-state behaviour of the pyridone substituent. Complex 4, a permanently porous Cu(II) material, shows no photoluminesence, but instead reveals a rare and intriguing inclined 2D?3D polyrotaxane architecture, an unusual class of mechanically interlocked network in which the particular coordination chemistry of the pyridone group facilitates alternating looped and linear structural features.

• Acceptance Date: May 17, 2018
• Publication Date: May 17, 2018
• Journal: Materials Chemistry Frontiers
• Print ISSN: 2052-1537
• Publisher: Royal Society of Chemistry
• DOI: https://doi.org/10.1039/C8QM00182K
• Publisher URL: http://doi.org/10.1039/C8QM00182K