Abstract
Fac-[MnBr(L
1,2
-κ
2
N
1
,
N
2
)(CO)
3
] and
fac
-[MnBr(L
3
)(CO)
3
] (
1–3
) (2,6-bis(benzimidazole-2′-yl)pyridine (L
1
), 2,6-bis(1-ethyl-benzimidazol-2′-yl)pyridine (L
2
) and 2-(2-pyridyl)benzimidazole (L
3
)), capable of CO release upon illumination at 468 nm, were synthesized and fully characterized, including the single crystal X-ray analysis of
1
and
2
. The photoCORMs are stable in the dark in DMSO and aqueous buffer under the reducing properties of the myoglobin assay. The κ
2
N
1
,
N
2
bidentate mode of L
1,2
ligands changes into meridional, tridentate mode upon illumination as illustrated
via
solution NMR studies. The influence of the alkylation of benzimidazole ligand on the electronic structure was studied using time dependent density functional theory calculations.