Carbonyl‐Terpyridyl‐Manganese Complexes: Syntheses, Crystal Structures, and Photo‐Activated Carbon Monoxide Release Properties

Abstract

International audienc

Selective synthesis and crystal structures of manganese(I) complexes with a bi- or tridentate terpyridine ligand

“…In I and II, the manganese(I) atoms exhibit distorted octahedral coordination environments, similar to those reported for other structurally related complexes (Compain et al, 2014(Compain et al, , 2015. In I, the fac configuration of the three CO ligands around the central manganese(I) atom is in agreement with the IR data of the complex and similar to those previously reported for complexes of this type (Compain et al, 2014(Compain et al, , 2015. As can be evinced from Fig.…”

“…The corresponding non-coordinating N atom, N3, is positioned on the side opposite to the Br atom. As a result, the torsion angle between the coordinating and non-coordinating pyridyl rings in I (N2-C13-C14-N3) is much smaller [47.9 (3) ] than those reported for related Mn I complexes with bidentate terpyridine derivatives (Compain et al, 2014(Compain et al, , 2015. The noncoordinating N atom is positioned in proximity of the equatorial carbonyl ligand (C2 O2), with a short value for the interatomic distance between C2 and N3 [2.900 (4) Å ].…”

“…Carbonylmanganese(I) complexes with polypyridyl ligands are of particular interest as novel active molecules that are able to release CO in response to photoirradiation (Carrington et al, 2013;Chakraborty et al, 2014;Jimenez et al, 2015) or as electrocatalysts of CO 2 reduction (Grills et al, 2018;Stanbury et al, 2017). Among these compounds, studies have concentrated mainly on tricarbonyl complexes comprising bidentate polypyridyl supporting ligands; by contrast, only few reports exist on dicarbonyl complexes bearing tridentate ligands (Compain et al, 2015;Machan & Kubiak, 2016). In fact, even though the typically tridentate ligands 2,2 0 :6 0 ,2 00 -terpyridine and derivatives thereof coordinate to an Mn I ion, the majority of them bind the metal ion in a bidentate manner (Compain et al, 2014;Moya et al, 2001).…”

“…As indicated by the results of studies focusing on the comparison between carbonylmanganese complexes containing bidentate and tridentate terpyridines (Compain et al, 2015;Machan & Kubiak, 2016), investigating the relationship between reactivity and molecular structure is a key research objective. However, comparing these two systems experimentally is difficult, particularly considering that available structural data on complexes comprising tridentate terpyridine ligands are quite scarce.…”

Near-Infrared and Visible Photoactivation to Uncage Carbon Monoxide from an Aqueous-Soluble PhotoCORM

“…The Mn-N bond lengths are ~0.2 Å longer than those found in h 3 -terpyridine Mn(I) complexes but close to those found for 3 and Mn(II) h 3 -tris(1-pyrazolyl)methane complexes. 36,37 Thus, the first stage photoreaction for solutions of complex 2 in DMSO, ethanol or water involves the labilization of one CO to give primarily a dicarbonyl complex, apparently the tricoordinate TPYOH complex Mn(CO)2(h 3 -TPYOH)X. The photochemical second stage, which is accelerated in aerobic media also results in CO release and, eventually, the formation of Mn(II)-TPYOH complexes (Scheme 3).…”