Accommodating Unwelcome Guests in Inorganic Layered Hosts: Inclusion of Chloranil in a Layered Double Hydroxide

Abstract

The host–guest chemistry of most inorganic layered solids is limited to ion-exchange reactions. The guest species are either cations or anions to compensate for the charge deficit, either positive or negative, of the inorganic layers. Here, we outline a strategy to include neutral molecules like <i>ortho</i>- and <i>para</i>-chloranil, that are known to be good acceptors in donor–acceptor or charge-transfer complexes, within the galleries of a layered solid. We have succeeded in including neutral <i>ortho-</i> and <i>para</i>-chloranil molecules within the galleries of an Mg-Al layered double hydroxide (LDH) by using charge-transfer interactions with preintercalated <i>p</i>-aminobenzoate ions as the driving force. The <i>p</i>-aminobenzoate ions are introduced in the Mg-Al LDH via ion exchange. The intercalated LDH can adsorb <i>ortho-</i> and <i>para</i>-chloranil from chloroform solutions by forming charge-transfer complexes with the <i>p</i>-aminobenzoate anions present in the galleries. We use X-ray diffraction, spectroscopy, and molecular dynamics simulations to establish the nature of interactions and arrangement of the charge-transfer complex within the galleries of the layered double hydroxide