Aerogels of 1D Coordination Polymers: From a Non-Porous Metal-Organic Crystal Structure to a Highly Porous Material

Abstract

The processing of an originally non- porous 1D coordination polymer as monolithic gel, xerogel and aerogel is reported as an alternative method to obtain novel metal- organic porous materials, conceptually different to conventional crystalline porous coordination polymer ( PCPs) or metal- organic frameworks ( MOFs). Although the work herein reported is focused upon a particular kind of coordination polymer ([ M( mu - ox)( 4- apy) 2] n, M: Co( II), Ni( II)), the results are of interest in the field of porous materials and of MOFs, as the employed synthetic approach implies that any coordination polymer could be processable as a mesoporous material. The polymerization conditions were fixed to obtain stiff gels at the synthesis stage. Gels were dried at ambient pressure and at supercritical conditions to render well shaped monolithic xerogels and aerogels, respectively. The monolithic shape of the synthesis product is another remarkable result, as it does not require a post- processing or the use of additives or binders. The aerogels of the 1D coordination polymers are featured by exhibiting high pore volumes and diameters ranging in the mesoporous/ macroporous regions which endow to these materials the ability to deal with large- sized molecules. The aerogel monoliths present markedly low densities ( 0.082- 0.311 g center dot cm - 3), an aspect of interest for applications that persecute light materials.