Back to overview

3d element complexes of pentadentate Bipyridine-Piyridine-based ligand scaffolds: Structures and photocatalytic activities

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Publication date 2013
Author Bachmann Cyril, Guttentag Miguel, Spingler Bernhard, Alberto Roger,
Project Homogeneous photocatalytic water splitting
Show all

Original article (peer-reviewed)

Journal Inorganic Chemistry
Volume (Issue) 52(10)
Page(s) 6055 - 61
Title of proceedings Inorganic Chemistry
DOI 10.1021/ic4004017


The synthesis of the two penta-pyridyl type ligands pyridine-2,6-diylbis(dipyridin-2-ylmethanol) (PPy, 1) and bis-2,2''-bipyridine-6-yl(pyridine-2-yl)methanol (aPPy, 2) is described. Both ligands coordinate rapidly to the 3d element cations Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II), thereby yielding complexes of the general composition [MBr(1)](+) and [MBr(2)](+), respectively. Further, the X-ray structures of selected complexes with ligands 1 and 2 are described. They show metal center dependent structural features and complexes with 2 exhibiting distinctly distorted octahedral geometries. Moreover, photocatalytic water reduction with [Co(II)Br(PPy)]Br (1c) and [Co(II)Br(aPPy)]Br (2c) as water reducing catalysts (WRC) was investigated. Both complexes showed catalytic activity in water when in presence of ascorbic acid as sacrificial electron donor and [Re(py)(bpy)(CO)3](+) (3) as photosensitizer (PS). Turnover numbers, TONs (H2/Co), up to 11,000 were achieved. Complex 2c was more active than 1c, whereas none of the other complexes showed any activity.