Recent advances in cyanoscorpionate chemistry: complexes with CO(II), MN(II), and NI(II)(cyclam)

Abstract

In the past, electronic and magnetic materials have been atom based materials made up of metals or metal-oxides. Functionally,these atom based materials are extremely efficient, however, they are very expensive to synthesize, very heavy, and possess limited flexibility. These properties limit the applications of traditional atom based materials where expense, weight, and flexibility are issues. Molecule based materials contain individual molecules which are inexpensively synthesized and made from predominantly light weight carbon, hydrogen, nitrogen, and oxygen. Coordination polymers containing transition metal centers with organic ligands can provide both electronic and magnetic properties as well as allow for light-weight and flexible molecule based materials. We have been investigating the synthesis of cyanoscorpionate ligands as components of coordination polymers. Over the last several years, our group has been investigating trispyrazolylborate (Tp) ligands containing the CN substituent in the 4-position of the pyrazole ring. The cyano group has a strong electronwithdrawing character, as well as the ability to coordinate to the metal. This allows the scorpionate to form various coordination polymers in which two cyanoscorpionate complexes are bound to the metal ion through the cyano group. In this paper we present recent work in this field, including the synthesis and structural characterization of complexes in which the cyano groups are coordinated to a central metal atom. These complexes represent the first step towards the synthesis of two-component coordination polymers involving this ligand class.