Structural characterization of metalloporphyrin-oligomer multianions by mass spectrometry and ion mobility spectrometry—Observation of metastable species

Schwarz, Ulrike; Vonderach, Matthias; Kappes, Manfred M.; Kelting, Rebecca; Brendle, Katrina; Weis, Patrick

doi:10.1016/j.ijms.2013.02.007

Cited by 10 publications

(23 citation statements)

References 35 publications

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“…As for the dimers we find completely different structural motifs for divalent versus trivalent metal centers: for the M III TPPS trimers (M = Mn, Fe) at both charge state 5– and 6– we again find structures that are connected by bonds between sulfonic acid groups and central metal atoms rather than through the counterions (see refs and ; for a figure of the structures, see below).…”

Section: Resultsmentioning

confidence: 81%

“…The observed daisy-chain-like structures are primarily determined by (partially ionic) bonds between the M III center of one porphyrin subunit and one of the sulfonic acid groups of another porphyrin. 11,12 Multianionic aggregates of M III TPPS, therefore, do not form (or do not retain) small H-or Jaggregate-like motifs under isolated solvent-free conditions.…”

Section: ■ Introductionmentioning

confidence: 99%

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Structures of Metalloporphyrin–Oligomer Multianions: Cofacial versus Coplanar Motifs as Resolved by Ion Mobility Spectrometry

et al. 2016

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ABSTRACT:We have combined ion mobility mass spectrometry with quantum chemical calculations to investigate the gasphase structures of multiply negatively charged oligomers of mesotetra(4-sulfonatophenyl)metalloporphyrins comprising the divalent metal centers Zn II , Cu II , and Pd II . Sets of candidate structures were obtained by geometry optimizations based on calculations at both the semiempirical PM7 and density functional theory (DFT) levels. The corresponding theoretical cross sections were calculated with the projection approximation and also with the trajectory method. By comparing these collision cross sections with the respective experimental values we were able to assign oligomer structures up to the tetramer. In most cases the cross sections of the lowest energy isomers predicted by theory were found to agree with the measurements to within the experimental uncertainty (2%). Specifically, we find that for a given oligomer size the structures are independent of the metal center but depend strongly on the charge state. Oligomers in low charge states with a correspondingly larger number of sodium counterions tend to form stacked, cofacial structures reminiscent of H-aggregate motifs observed in solution. By contrast, in higher charge states, the stack opens to form coplanar structures. ■ INTRODUCTIONMetalloporphyrins constitute the reactive centers in a large number of biochemical systems such as hemoglobin, myoglobin, and chlorophyll. As a consequence, they are wellstudied in condensed phase. 1 It is also well-known that porphyrins and metalloporphyrins can self-assemble into larger oligomers in solution. This aggregation has attracted considerable interest, especially for porphyrins functionalized with highly polar groups such as sulfonic acids. 2−9 Much of this effort has been focused on water-soluble meso-tetra(4-sulfonatophenyl)porphyrin (TPPS). Ribóet al. 6 investigated aqueous solutions thereof spectroscopically. In studies performed at various concentrations and pH values, they found evidence for the formation of small J (edge-to-edge) and H (face-to-face) aggregates. The light scattering measurements of Micali et al. 10 have in fact suggested that even larger mesoscopicself-similar clusters of TPPS J-aggregates may form in solution. More recently, Hollingsworth et al. 9 have investigated the aggregation of TPPS in aqueous solution using UV−vis and fluorescence spectroscopy, small-angle X-ray scattering, analytical ultracentrifugation, and transmission electron microscopy. They inferred stacks of ring structures containing typically 25 monomeric units.TPPS oligomers as well as aggregates of the corresponding metalloporphyrins, MTPPS, can also be prepared and studied in gas phase, i.e., in the absence of solvent molecules. For example, multiply negatively charged aggregates of MTPPS (also containing sodium counterions) can be generated by electrospray ionization (ESI) and detected with mass spectrometry. To what extent such isolated aggregates can also provide an indirect measure of aggregatio...

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Section: Resultsmentioning

confidence: 81%

Section: ■ Introductionmentioning

confidence: 99%

Structures of Metalloporphyrin–Oligomer Multianions: Cofacial versus Coplanar Motifs as Resolved by Ion Mobility Spectrometry

et al. 2016

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“…Porphyrins have been studied in the gas phase using mass 6 and ion mobility 7,8 spectrometry, as well as infrared, 9 photodissociation 10 and photoelectron spectroscopy. [11][12][13][14] Protoporphyrin IX is a D 2h porphyrin with two propionic acid groups as substituents on the macrocycle, which can form a carboxylate monoanion or dicarboxylate dianion following the removal of one or two protons.…”

Section: Introductionmentioning

confidence: 99%

Photoelectron spectroscopy of the protoporphyrin IX dianion

Gibbard

Clarke

Verlet

2021

Phys. Chem. Chem. Phys.

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“…Another example of careful comparison between modelled and experimental cross sections is demonstrated by the structural determination of metalloporphyrin oligomeric assemblies ( Schwarz et al, 2013 ; Schwarz et al, 2014 ). Interestingly, as hydrogen counterions were exchanged for sodium counterions, topological changes of the dimer were observed using TWIMS ( Schneider et al, 2018 ).…”

Section: Applications Of Ion Mobility Mass Spectrometry To Study Coordination Driven Self-assemblymentioning

confidence: 99%

Reaction Monitoring and Structural Characterisation of Coordination Driven Self-Assembled Systems by Ion Mobility-Mass Spectrometry

Williams

Rijs

2021

Front. Chem.

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Nature creates exquisite molecular assemblies, required for the molecular-level functions of life, via self-assembly. Understanding and harnessing these complex processes presents an immense opportunity for the design and fabrication of advanced functional materials. However, the significant industrial potential of self-assembly to fabricate highly functional materials is hampered by a lack of knowledge of critical reaction intermediates, mechanisms, and kinetics. As we move beyond the covalent synthetic regime, into the domain of non-covalent interactions occupied by self-assembly, harnessing and embracing complexity is a must, and non-targeted analyses of dynamic systems are becoming increasingly important. Coordination driven self-assembly is an important subtype of self-assembly that presents several wicked analytical challenges. These challenges are “wicked” due the very complexity desired confounding the analysis of products, intermediates, and pathways, therefore limiting reaction optimisation, tuning, and ultimately, utility. Ion Mobility-Mass Spectrometry solves many of the most challenging analytical problems in separating and analysing the structure of both simple and complex species formed via coordination driven self-assembly. Thus, due to the emerging importance of ion mobility mass spectrometry as an analytical technique tackling complex systems, this review highlights exciting recent applications. These include equilibrium monitoring, structural and dynamic analysis of previously analytically inaccessible complex interlinked structures and the process of self-sorting. The vast and largely untapped potential of ion mobility mass spectrometry to coordination driven self-assembly is yet to be fully realised. Therefore, we also propose where current analytical approaches can be built upon to allow for greater insight into the complexity and structural dynamics involved in self-assembly.

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Structural characterization of metalloporphyrin-oligomer multianions by mass spectrometry and ion mobility spectrometry—Observation of metastable species

Cited by 10 publications

References 35 publications

Structures of Metalloporphyrin–Oligomer Multianions: Cofacial versus Coplanar Motifs as Resolved by Ion Mobility Spectrometry

Structures of Metalloporphyrin–Oligomer Multianions: Cofacial versus Coplanar Motifs as Resolved by Ion Mobility Spectrometry

Photoelectron spectroscopy of the protoporphyrin IX dianion

Reaction Monitoring and Structural Characterisation of Coordination Driven Self-Assembled Systems by Ion Mobility-Mass Spectrometry

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