MARIO PAGLIARO
Istituto per lo Studio dei Materiali Nanostrutturati, CNR, Palermo, Italy

The last barrier amid conventional chemistry disciplines broke in 2002 when Avnir and co-workers in Israel reported the discovery of a new hybrid material: a noble metal (silver) molecularly doped with organic molecules (1). Not only water-soluble Congo red, Safranin-O, and thionine were successfully entrapped in metallic silver, but also Sudan III insoluble in water could be entrapped by dissolving it with sodium dodecyl sulfate.

It is enough to reduce Ag⁺ dissolved in water with a reducing agent like sodium hypophosphite in the presence of the organic molecules dissolved or emulsified, to obtain a completely unexpected class of materials for which we in 2009 coined the term MORALS (metal-organic alloys) (2).

A new type of alloy, accessed at room temperature via a wet and mild chemistry process, upon which organic molecules are not adsorbed at the surface of the metal but rather 3-dimensionally caged within the narrow pores of agglomerated metal nanocrystals.

Reviewing the new field in 2014, Avnir emphasized how the newly achieved ability to functionalize metals with any “the many millions ...