What Is Required to Stabilize Al³⁺? A Gas-Phase Perspective

Abstract

With a combination of experiment and theory (ab initio and DFT), we demonstrate that the Al(3+) cation can be stabilized in the gas phase using ligands, which have the ability to act as powerful sigma electron donors and electron acceptors. The latter property, which implies that electron density from the aluminum cation moves into ligand antibonding orbitals, has not previously been considered significant when accounting for the behavior of Al(3+). Of the three ligands identified as falling into the above category, acetonitrile appears to form the most stable complexes in the gas phase, which is in accord with the long established fact that solid-state complexes with Al(3+) are readily isolated. From the results, it is suggested that chain or ring compounds containing the -C triple bond N group might act as successful sequestering agents for Al(3+) from aqueous solutions.

Formation of hydrated triply charged metal ions from aqueous solutions using nanodrop mass spectrometry

“…Clusters containing singly charged metal ions have been formed using several different methods and the structures of these clusters have been investigated in significant detail [1][2][3][4][5][6][7]. Formation of hydrated multiply charged ions is more challenging due to competing effects of dissociation aided by Coulomb repulsion of two charged product ions [8][9][10][11][12][13][14][15][16][17][18][19][20]. For example, a single water molecule can be readily attached to Ca 2+ .…”

“…An alternative approach to forming these triply charged clusters has been employed by Stace and coworkers in which ligated, neutral clusters are formed and subsequently ionized by electron impact [20,30]. With this technique, [HoL n ] 3+ clusters have been formed where L = acetone or acetonitrile [30], and [AlL n ] 3+ clusters were formed where L = DMSO, pyridine, or acetonitrile [20].…”

“…With this technique, [HoL n ] 3+ clusters have been formed where L = acetone or acetonitrile [30], and [AlL n ] 3+ clusters were formed where L = DMSO, pyridine, or acetonitrile [20]. No [M(H 2 O) n ] 3+ clusters were observed for either of these metal ions; in both cases, reduced charge species were formed instead.…”

Trapping and recording the collision- and photo-induced fragmentation patterns of multiply charged metal complexes in the gas phase

“…Examples of the types of di-and trication complexes that can be generated, range from the very simple, such as [Cu(Ar) N ] 2+ [26], through to [Al(CH 3 CN) 4 ] 3+ [28], which has an established solid-state chemistry. In addition, the pick-up technique is capable of generating complexes in charge states that are difficult to assess by other means, for example, those involving silver(II) [29] and gold(II) [30].…”

A study of the coordination shell of aluminum(III) and magnesium(II) in model protein environments: Thermodynamics of the complex formation and metal exchange reactions

“…Although theory has made quite a progress in the field [7], relevant to this issue are recent advances in gas-phase methods (electrospray ionization, charge striping spectroscopy, double-charge spectroscopy, blackbody infrared radiative dissociation, etc.) for they provide the opportunity to study not only monocharged but multiple charged cations [8][9][10][11][12][13].…”