Synthesis, solid-state and in-solution structures of a new seven coordinated manganese(II) complex via X-ray diffraction and electrospray ionization mass spectrometry

The structure of the [Mn(HPClNOL)(η1-NO3)(η2-NO3)] 1 complex [HPClNOL = 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol] in the solid-state and in H2O/MeOH solution was investigated by monocrystal X-ray diffraction and ESI(+)–MS/MS. X-ray reveals that 1 is a seven-coordinated complex with a discrete mononuclear structure in which the manganese(II) ion is coordinated by the tripodal HPClNOL ligand and two nitrate ions, one monodentate and the other bidentate. ESI(+)–MS/MS shows that mononuclear, dinuclear and trinuclear manganese cationic species are present in solution, probably in equilibrium with neutral 1. This contrasting scenario illustrates for 1 the importance of both solid-state and in-solution characterizations of coordination compounds with potential bioinorganic interest.

Graphical abstractThe new compound [Mn(HPClNOL)(η1-NO3)(η2-NO3)] 1 posses a seven-coordinated manganese(II) ion in solid-state, showing a N3O4 coordination environment. ESI(+)–MS/MS studies of this water soluble compound reveals that in water:methanol (1:1) solutions, the solid-state structure is not preserved, since at least four other structures were detected.Figure optionsDownload full-size imageDownload as PowerPoint slide