The chameleon-like coordinating ability of 2,3-di(pyridyl)pyrazine-type ligands

• Published in: Coordination chemistry reviews 2017-09, Vol.347, p.115-140
• Main Authors: Floris, Barbara, Donzello, Maria Pia, Ercolani, Claudio, Viola, Elisa
• Format: Article
• Language: English
• Subjects: 2,3-Di(2-pyridyl)pyrazine; Mono-, di-, and multimetallic complexes; Polyazine tetra N donors; “py-py” and “py-pyz” coordination
• ISSN: 0010-8545; 1873-3840
• DOI: 10.1016/j.ccr.2017.06.005

This survey is dedicated to the multifaceted modes of binding of metal ions by polyazine N donors like 2,3-di(2-pyridyl)pyrazine (dpp), 5,6-di(2-pyridyl)quinoxaline (dpq) and 9,10-di(2-pyridyl)benzoquinoxaline (dpbq) and related substituted analogs, covered until the end of 2016. These compounds display the potential coordination of the dipyridinopyrazine block consisting of two pyridine and two pyrazine N donor atoms. This report illustrates the structural features of the mono-, di- and multinuclear complexes, whenever crystallographic information was available. In the absence of X-ray work, as is the case for tri-, tetra-, and multinuclear systems, the overall organization of the complex systems is that proposed by the authors. Synthetic procedures, physicochemical properties, especially UV–visible spectroscopic and electrochemical behaviour, are given some attention.