α-Pyrrolyl dipyrrins as suitable ligands for coordination chemistry

• DOI: 10.1016/j.ccr.2017.08.002
• Publication Date: 2017-09-02T04:57:58Z
• Authors: Ritambhara Sharma; M. Rajeswara Rao; Mangalampalli Rav...
• Keywords: Pyrrole; BODIPY

Abstract α-Pyrrole substituted dipyrrins (α-pyrrolyl dipyrrins) which belong to the family of natural products known as prodigiosins possess potent immunosuppressive, antimicrobial, antimalarial and cytotoxic properties. These tripyrrolic prodigiosin types of systems have attracted attention as versatile ligands for boron and for metals to form complexes which possess interesting properties and biological activity. The pyrrolyl dipyrrin is dianionic and can act as either bidentate or tridentate ligand to form complexes. In this review, we described rational routes to prepare α-pyrrolyl dipyrrin ligands and their use in the formation of metal and BF 2 -complexes. The α-pyrrolyl dipyrrins bound to metals either via two dipyrromethene pyrrole nitrogens or using all three pyrrolic nitrogens depending on the type of metal ion. However, the pyrrolyl dipyrrins act as bidentate ligands to form highly fluorescent BF 2 -complexes of pyrrolyl dipyrrins (3-pyrrolyl BODIPYs). The appended pyrrole ring in 3-pyrrolyl BODIPYs was functionalized with a wide range of functional groups and the functionalized 3-pyrrolyl BODIPYs were subsequently used to construct several novel 3-pyrrolyl BODIPY based fluorescent systems and conjugates. The structural, spectral and electrochemical properties of a variety of 3-pyrrolyl BODIPY based fluorescent systems and their conjugates are discussed in this review.