Synthesis, Structure and Properties of Metal–Organic Framework Materials Organized by the 1,8–Naphthalimide π–stacking Synthon
Date of Award
Campus Access Dissertation
Chemistry and Biochemistry
DANIEL L REGER
A family of new bifunctional carboxylate ligands 2–(1,8–naphthalimido)ethanoate (LC1-), 3–(1,8–naphthalimido)propanoate (LC2-), 4–(1,8–naphthalimido)butanoate (LC3-), 4–(1,8–naphthalimido)benzoate (LC4-), and 2–(1,8–naphthalimido)benzoate (Lophen-) containing the carboxylate donor group linked to the robust π···π stacking 1,8–naphthalimide supramolecular synthon has been designed in order to construct MOF like architectures (termed supramolecular metal–organic frameworks, SMOFs) organized partially or completely by supramolecular interactions of the 1,8–naphthalimide rings. These ligands were used to investigate how systematic modifications (by changing the length and type of the link between the carboxylate donor group and the 1,8–naphthalimide ring) impact molecular and supramolecular structure, and also the properties of the obtained metal complexes.
Copper, zinc, and rhodium complexes were prepared with these carboxylate ligands, and the structural analysis and properties of these complexes are discussed. All of the structures are highly organized, dominated by the π···π stacking of the naphthalimide groups. In addition hydrogen bonding interactions can support the three–dimensional architecture of the networks when ligands capable of such interaction are incorporated into the structure.
Building these carboxylate ligands into the dicopper paddlewheel unit leads to solids with strong antiferromagnetic coupling between the copper(II) centers as demonstrated by magnetic and EPR measurements. Assembling the dimeric zinc paddlewheel cores by supramolecular interactions leads to materials with novel properties as well as unique structural characteristics. The flexible but strong π···π stacking interaction of the naphthalimide rings allows local distortions of the robust frameworks to permit temperature induced phase changes and the exchange of new guest molecules without the loss of crystallinity.
To expand the chemistry of SMOF solids to the synthesis of chiral framework materials a new trifunctional ligand (S)–2–(1,8–naphthalimido)propanoate, (Lala-) (containing a carboxylate donor group, a homochiral center derived from naturally–occurring amino acid, and a strong π···π stacking, 1,8–naphthalimide synthon), was also designed. The structural analysis of the supramolecularly–organized zinc(II) and cadmium(II) complexes of this ligand is presented. The photoluminescent properties of the compounds are also covered.
DEBRECZENI, A.(2012). Synthesis, Structure and Properties of Metal–Organic Framework Materials Organized by the 1,8–Naphthalimide π–stacking Synthon. (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/672