The Aggregations and Strong Emissions of d8 and d10 Metal−8-Hydroxyquinaldine Complexes

Five new d 8 and d 10 metal complexes, Pd(8-hq) 2 ( 1 ), [Ag(8-Hhq) 2 ]NO 3 ( 2 ), Ag(8-hq)(8-Hhq) ( 3 ), [(8-H 2 hq) 2 PdCl 4 ]·2H 2 O ( 4 ), and Pt(8-hq)(tht)Cl ( 5 ) (tht = tetrahydrothiophene), all with a fluorogenic chelating agent, 8-hydroxyquinaldine (8-Hhq), have been synthesized and characterized. The aggregations of their photoactive metal centers through π−π stacking and hydrogen bonding interactions construct the interesting frameworks. The strong emissions of 1 − 3 and 5 in solid states with orange, cyan, and green luminescences originating from metal··· metal and π−π interactions are assigned as metal to ligand charge transfer/metal–metal to ligand charge transfer/intraligand emissions. The solvent effects on their photophysical properties are examined, which exhibit a wide range of strong luminescences in the different organic solvents. In addition, time-dependent density functional theory calculations using the B3LYP functional on 1 are in good agreement with the experiments. Thermogravimetric analyses and UV/vis spectra with composition of certain simulated results are also reported.