Title : Dipyrromethanes: Structural analogues for probing the chemistry of bilirubin pigments

Abstract:

2,2’-Dipyrromethanes (dipyrranes) are a class of ligand that is partially conjugated and comprising two pyrrole rings fused at the meso carbon atom (Fig1a). These ligand systems serve as precursors for the synthesis of porphyrins and related macrocyclic structures. Formed by the condensation of an aldehyde with excess pyrrole under controlled conditions, dipyrranes are exceedingly popular as sensors, probes and catalysts. This is primarily due to their predictable transition metal coordination chemistry and favourable fluorescent properties. Our interest in dipyrranes (and their transition metal complexes) is their structural similarity to bilirubin, thus serving as a suitable analogue for probing the coordination chemistry of bilirubin pigments. This preliminary work reports on the successful synthesis and spectroscopic characterization of selected meso-substituted dipyrranes: 5-phenyl dipyrromethane; 5-(4-hydroxyphenyl) dipyrromethane and 5-(4-nitrophenyl) dipyrromethane. Ligands were synthesized using methods adapted from Lindsey et al., and characterized by spectroscopy (NMR, UV-Vis, LCMS, IR), melting point analysis and crystallography.

Biography:

Dr Sadhna Mathura is an academic at the University of the Witwatersrand in Johannesburg, South Africa. She obtained her Doctorate in Bioinorganic Chemistry from the same institution for her significant contribution to the understanding of vitamin B12 and cobalt chemistry. Her work was recognised through several doctoral scholarships and doctoral publications. She provided quality Chemistry training to 3 postgraduate students, and well over a 100 undergraduate students, many of whom have gone on to further their Chemistry career. She is a member of the chemistry professional bodies: IUPAC, ACS, RSC, FASC and SACI