Guanidine Catalysts for Depollution of Water: Challenge to Environmental Problems from Organic Chemistry

Abstract

Depollution of water contaminating toxic substance has been very serious environmental problems to be solved. Bisguanidinobenzene is designed as a potential scavenger for toxic substances, such as metal salts or arsenic acid, because of its strongly basic multi-nitrogen functionality. Mixing of it with several kinds of metal salts under aqueous conditions suggested wide ranges of possible coordination, from which the host was quantitatively recovered from the complex by extraction. Job's plot and tituration experiment in the NMR study indicated that arsenic and phosphoric acids could be also scavenged with bisguanidinobenzene. The same host-guest interaction was, as expected, observed after structural modification of bisguanidinobenzenes to recyclable polymer-supported derivatives.