Studies on stabilities of nickel(II) and zinc(II) complexes of substituted diphenylcarbazones and thiocarbazones

Abstract

The Influence of electron-withdrawing substituents on the formation constants of the complexes of nlckel(II) and zlnc(II) with substituted diphenylcarbazones and dlphenylthlocarbazones has been studied. Change of the environment had a profound Influence on the spectra of the ligands containing nitro groups.

An irreversible planar optical sensor for multi-dimensional measurements of sedimentary H2S

“…As shown in Fig. 1, DPCO has very weak absorption in the range of 400-650 nm in both ethanol solution and D4 hydrogel membranes, the addition of Zn 2 + , however, immediately yields a dark pink DPCO-Zn 2 + complex with maximum absorption at 530 nm and formation constant logK 6.32 (Math et al, 1985). Upon addition of sulfide, a competing reaction between DPCO in the DPCO-Zn 2 + complex and S 2 − occurs due to the high formation constant of ZnS (K sp = 2 × 10 − 25 at 25°C).…”

“…In this work, DPCO was selected as a ligand to form a complex with Zn 2 + due to its rapid reaction with Zn 2 + and moderate formation constant of DPCO-Zn 2 + (Math et al, 1985), parameters critical for developing the H 2 S sensor. As shown in Fig.…”