Heat Stability Studies on Chelates from Schiff Bases of

Heat Stability Studies on Chelates from Schiff Bases of Salicylaldehyde Derivatives. I1. BY c. s. hfARVEL AND N. TARKOY'. RECEIVED OCTOBER 5, 1957...
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C.S.MARVEL A N D N. TARKOY

832

[CONTRIBUTION FROM THE

VCJ1. 80

NOYESCHEMICAL LABORATORY, UNIVERSITY

OF I L L I N O I S ]

Heat Stability Studies on Chelates from Schiff Bases of Salicylaldehyde Derivatives.

I1 BY

c. s. h f A R V E L AND N. TARKOY' RECEIVED OCTOBER5, 1957

The influence of the sulfone group in the 5,5'-position of a his-salicylaldehyde Schiff base upon the heat stabilities of the corresponding metal chelates was studied, Best stabilities were found in the nickel and cadmium chelates, showing, respectively, 0.09 and 0.27% weight loss per hour at 250' in air, the corresponding values for 300" being 1.1 and 1.3%. The greatly enhanced heat stability of these chelates as compared with the 5,5'-methylene-bis-salicylaldehgde series was interpreted in terms of increased acidity of the phenolic groups, The heat degradation of the cobalt, nickel, iron and cadmium chelates seems t o be a thermal process.

I n continuation of former work2 on metal chelated aromatic polymeric Schiff bases of type I as an approach to the synthesis of heat-stable polymeric materials, the present study deals with the influence of electron-withdrawing groups, such as X in foriiiul:~I , on the stability of these chelates.

monomer of type I where X = -SO,-. This group is sufficiently electron withdrawing, is known for high thermal stability6 and seems also sterically suitable.' Attempts to introduce aldehyde groups into the 3- :md :