A Schiff base and its copper(II) complex as a highly selective chemodosimeter for mercury(II) involving preferential hydrolysis of aldimine over an ester group.
The syntheses of a new Schiff base, diethyl-5-(2-hydroxybenzylidene)aminoisophthalate (HL), and a copper complex, [Cu(L2)] (1), imparting L(-), have been described. Both the ligand HL and complex 1 have been thoroughly characterized by elemental analyses, electrospray ionization mass spectrometry, FT-IR, NMR ((1)H and (13)C), electronic absorption, and emission spectral studies and their structures determined by X-ray single-crystal analyses. Distinctive chemodosimetric behavior of HL and 1 toward Hg(2+) has been established by UV/vis, emission, and mass spectral studies. Comparative studies further revealed that the chemodosimetric response solely originates from selective hydrolysis of the aldimine moiety over the ester group and 1 exhibited greater selectivity toward Hg(2+) relative to HL while the sensitivity order is reversed. Further, these followed different hydrolytic pathways but ended up with the same product analyzed for diethyl-5-aminoisophthalate (DEA). Hg(2+)-induced displacement of Cu(2+) and subsequent hydrolysis of the -HC═N- moiety in 1 affirmed the identity of the actual species undergoing hydrolysis as HL. The occurrence of Cu(2+) displacement and Hg(2+) detection via hydrolytic transformation has been supported by various physicochemical studies.
Department of Chemistry, Faculty of Science, Banaras Hindu University , Varanasi 221 005, U.P., India.
Ashish
A
Kumar
Mrigendra
M
Dubey
Rampal
R
Pandey
Rakesh Kumar
RK
Gupta
Amit
A
Kumar
Alok Ch
ACh
Kalita
Daya Shankar
DS
Pandey
D003300:Copper / Q000737:chemistry*; D004952:Esters / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D006868:Hydrolysis; D007097:Imines / Q000737:chemistry*; D008024:Ligands; D008628:Mercury / Q000032:analysis*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D012545:Schiff Bases / Q000138:chemical synthesis / Q000737:chemistry
D004952:Esters; D005456:Fluorescent Dyes; D007097:Imines; D008024:Ligands; D009942:Organometallic Compounds; D012545:Schiff Bases; D003300:Copper; D008628:Mercury