Energy‐Resolved Collision‐Induced Dissociation Studies of 2,2′‐Bipyridine Complexes of the Late First‐Row Divalent Transition‐Metal Cations: Determination of the Third‐Sequential Binding Energies

Abstract

The third‐sequential binding energies of the late first‐row divalent transition‐metal cations with 2,2′‐bipyridine (Bpy) are determined using guided‐ion‐beam tandem mass spectrometry (GIBMS) techniques. The metal cations investigated include the late first‐row divalent transition‐metal cations, Fe2+, Co2+, Ni2+, Cu2+, and Zn2+. The kinetic‐energy‐dependent cross sections for collision‐induced dissociation (CID) of the M2+(Bpy)3 complexes are analyzed to extract absolute 0 and 298 K bond dissociation energies (BDEs) for the loss of an intact Bpy ligand. Theoretical electronic structure calculations at the B3LYP, BHandHLYP, and M06 levels of theory are performed to determine stable geometries and sequential BDEs of the M2+(Bpy)x complexes (x=1–3). BDEs computed using the M06 functional are the largest, BHandHLYP values are intermediate, whereas B3LYP produces the smallest values. Very good agreement between the B3LYP theoretically calculated and threshold collision‐induced dissociation experimentally determined BDEs is found, which suggests that the B3LYP functional is capable of accurately describing the binding in these M2+(Bpy)3 complexes. Periodic trends in the binding of the M2+(Bpy)x complexes are examined and compared to the analogous complexes with 1,10‐phenanthroline (Phen), M2+(Phen)x. Comparisons are also made to the analogous Bpy complexes, M+(Bpy)x, with the late first‐row monovalent transition‐metal cations, Co+, Ni+, Cu+, and Zn+ investigated previously.

Disassembly Mechanisms and Energetics of Polymetallic Rings and Rotaxanes with Ion Mobility Mass Spectrometry

“…15 The lability of [RingCu]is a result of Jahn-Teller distortions causing the elongation of one of the F-Cu II -O axes, 16 which is well-known from other Cu II complexes and its impact on periodic trends previously reported. 17,18 Jahn-Teller effects could also make [RingCu]more flexible, as observed before for related structures containing five-coordinate Cu II sites. 19 Notably, our data agree well with the M II trend for water-exchange reaction rate constants of the hexaaqua ions [M II (H2O)6] 2+ (Table S5, Figure S32), although a different stability trend from ESI-MS experiments has recently been reported for supramolecular terpyridine-based complexes (Ni II > Co II > Zn II > Fe II > Cu II > Cd II > Mn II ), indicating that the electronic environment of M II may be altered in the case of some ligands.…”

Alkali metal cation binding affinities of cytosine in the gas phase: revisited

“…The model represented by eqn ( 1) is expected to be appropriate for translationally driven reactions 59 and has been found to reproduce CID cross sections well. [60][61][62][63][64] The model of eqn (1) is convoluted with the kinetic energy distributions of both the reactant M + (cytosine) complex and neutral Xe atom, and a nonlinear least-squares analysis of the zero-pressure-extrapolated CID cross sections are performed to give optimized values for the parameters, s 0 , E 0 , and n. The error associated with the measurement of E 0 is estimated from the range of threshold values determined from the zero-pressure-extrapolated cross sections, variations associated with uncertainties in the vibrational frequencies (AE10% scaling as discussed above), and the error in the absolute energy scale, AE0.05 eV (Lab). For analyses that include the RRKM lifetime analysis, the uncertainties in the reported E 0 (PSL) and E 0 (TTS) values also include the effects of increasing and decreasing the time assumed available for dissociation (B10 À4 s) by a factor of two.…”

Base-Pairing Energies of Proton-Bound Dimers and Proton Affinities of 1-Methyl-5-Halocytosines: Implications for the Effects of Halogenation on the Stability of the DNAi-Motif

“…The threshold regions of the measured CID cross-sections are modeled using procedures developed elsewhere [55][56][57][58][59][60][61][62] that have been found to reproduce CID cross-sections well [63][64][65][66][67]. Details regarding data handling and analysis procedures, which includes explicitly accounting for the internal and translational energy distributions of the reactant proton-bound dimers, the effects of multiple ion-neutral collisions, and the lifetime of the dissociating proton-bound dimers, are summarized in the Supplementary Information.…”