Optical properties of zinc(II) 5,7-diiodo-8-quinolinolate in solution. Phosphorescence under ambient conditions

The emission spectrum of Zn(DIQ)2 with DIQ=5,7-diiodo-8-quinolinolate consists of an intraligand (IL) fluorescence at λmax=550 nm and a rather weak IL phosphorescence at λmax=804 nm. While the appearance of the phosphorescence under ambient conditions is certainly caused by the heavy atom effect of the iodine substituents their influence is smaller than might be expected.