157982-82-6Relevant articles and documents
Synthesis, X-ray crystallography, thermal studies, spectroscopic and electrochemistry investigations of uranyl Schiff base complexes
Asadi, Zahra,Shorkaei, Mohammad Ranjkesh
, p. 344 - 351 (2013)
Some tetradentate salen type Schiff bases and their uranyl complexes were synthesized and characterized by UV-Vis, NMR, IR, TG, C.H.N. and X-ray crystallographic studies. From these investigations it is confirmed that a solvent molecule occupied the fifth position of the equatorial plane of the distorted pentagonal bipyramidal structure. Also, the kinetics of complex decomposition by using thermo gravimetric methods (TG) was studied. The thermal decomposition reactions are first order for the studied complexes. To examine the properties of uranyl complexes according to the substitutional groups, we have carried out the electrochemical studies. The electrochemical reactions of uranyl Schiff base complexes in acetonitrile were reversible.
Influences of polarizability effect of alkyl group and homoring competition effect of substituents on the NMR spectra of salen-type Schiff base
Wei, Bai-ying,Cao, Chen-zhong,Cao, Chao-tun
, p. 701 - 712 (2021/02/12)
Salen-type Schiff bases are a kind of important compounds and are widely used. In order to explore the effect of alkyl groups and substituents attached to aromatic ring on the chemical shifts, 63 title compounds were synthesized. Their 1H NMR and 13C NMR spectra were obtained; and the effects of the alkyl chain length and substituents on the chemical shifts (δH(CH=N), δC(CH=N), δH(OH), and δC(C-OH)) were studied. The results show that (1) the alkyl polarizability effect index (PEI) has an important influence on the chemical shifts of the above four atoms, with the increase of PEI, the values of δH(CH=N) and δc(CH=N) decrease, and the values of δH(OH) and δC(C-OH) increase. (2) The influence of substituent X attached to aromatic ring on the chemical shift is related to its position by taking OH or CH=N as reference. As for the effect of substituent on the chemical shifts, the effect of Hammett constant σ(X)-OH and excited-state substituent parameter (Formula presented.) with OH as reference are different from that ofσ(X)-CH=N and (Formula presented.) with CH=N as reference, and there is a “homoring competition effect” of the substituent. (3) The effect of the cross-interaction between X and OH on the chemical shift is also significantly different due to the different position of X. Quantitative correlation equations against chemical shifts were built for the four atoms, and the stability and prediction ability of the obtained equations were confirmed by leave-one-out cross validation.
Substitutional group dependent colori/fluorimetric sensing of Mn2+, Fe3+ and Zn2+ ions by simple Schiff base chemosensor
Hariharan,Anthony, Savarimuthu Philip
, p. 1658 - 1665 (2015/03/30)
Schiff base is one of the easiest synthesizable chemosensor and exhibit strong coordination with metal ions; the property that has been vastly exploited for metal ions sensing. Simple Schiff base chemosensors (1a-d and 2a-d) were synthesized and demonstrated substitutional group dependent colorimetric sensing of metal ions. Chemosensor without (1a, 2a) and OCH3 substitution (1b, 2b) did not show any significant colour change for metal ions. However, a highly selective colorimetric change (colourless to pink) for Mn2+ ions (10-6 M) was observed with diethylamine substituted 1c, 2c. Hydroxyl substitution (1d, 2d) leads to selective colorimetric sensing (colourless to orange) of Fe3+ ions (10-6 M). PVA thin films of 2c/2d were fabricated and demonstrated selective colorimetric sensing of Mn2+ and Fe3+ ions. The practical applicability of the synthesized chemosensors were also demonstrated by performing selective colorimetric sensing of Mn2+ and Fe3+ ions in real samples such as tap, ground, pond and river water. Effect of substitution on the fluorescence selectivity of Zn2+ has also been investigated.
