Determination of the relative ligand-binding strengths in heteroleptic IrIII complexes by ESI-Q-TOF tandem mass spectrometry

作者：Altuntas Esra; Winter Andreas; Baumgaertel Anja; Paulus Renzo M; Ulbricht Christoph; Crecelius Anna C; Risch Nikolaus; Schubert Ulrich S^*

来源：Journal of Mass Spectrometry, 2012, 47(1): 34-40.

DOI：10.1002/jms.2023

• ESI MS
• tandem mass spectrometry
• relative binding strength
• iridium(III) complexes

An electrospray ionization quadrupole time-of-flight mass spectrometer has been utilized to investigate the relative ligand-binding strengths in a series of heteroleptic-charged iridium(III) complexes of the general formula [(C boolean AND N)2IrIII(S-tpy)](PF6) by using variable collision energies. Collision-induced dissociation experiments were performed in order to study the stability of the IrIII complexes that are, for instance, suitable phosphors in light-emitting electrochemical cells. The ratio of signal intensities belonging to the fragment and the undissociated complex depends on the collision energy applied for the tandem mass spectra (MS/MS) analysis. By defining the threshold collision energy and the point of complete complex dissociation, it is possible to estimate the relative complex stabilities depending on the nature of the coordinated ligands [i.e. type of cyclometalating ligand (C boolean AND N), substituents on the S-shaped terpyridine (S-tpy)]. The collision energy values differed as a function of the coordination sphere of the IrIII centers.

• 出版日期2012-1