Crystal Structure and Photoluminescence Properties of Gadolinium Picrate Triethylene Glycol Complex

Abstract

The [Gd(Pic)2(H2O)(EO3)](Pic)·CH3OH complex, where EO3 = triethylene glycol, and Pic = picrate anion, has been prepared and characterized. The complex is crystallized in triclinic with space group P-1. The Gd(III) ion is coordinated to nine donor oxygen atoms from one EO3 ligand, two Pic anions and one water molecule. The geometric arrangement of the heavier lanthanide–picrate complex is different with the lighter lanthanide–picrate complexes as observed. The charge balancing and steric hindrance of the bulky of picrate anion have influenced the geometric arrangement in the inner-sphere. Two intramolecular hydrogen bonds O1–H1O1···O26 and C6–H6A···O13 help in stabilizing of complex. Extensive intermolecular hydrogen bonds O–H···O and C–H···O linked the molecules into two-dimensional layer and parallel to the (011) plane as observed. No metal centered emission can be observed for the Gd complex. The phosphorescence spectrum of Gd complex in the solid state showed the central peak at 537.8 nm which related to the emission of the picrate anion. The [Gd(Pic)2(H2O)(EO3)](Pic)·CH3OH complex was synthesized. The Gd(III) ion is coordinated to nine donor oxygen atoms. The steric hindrance of the bulky of picrate anion have influenced the inner-sphere. Extensive intermolecular hydrogen bonds linked the molecules into two-dimensional layer. No metal centered emission can be observed for the Gd complex.