Fabian Menges

Fabian Menges
Yale University | YU · Department of Chemistry

Dr.

About

42
Publications
2,091
Reads
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856
Citations
Introduction
GC and LC-MS for qualitative and quantitative characterization of compounds. Method and instrumentation development in various mass spectrometry related fields, especially cryogenic vibrational spectroscopy on mass selected ions. Guest Editor for the upcoming special issue "Spectroscopic Probes of Ion-Molecule Interactions in the Gas Phase" - please see https://www.mdpi.com/journal/ijms/special_issues/Spectroscopic_Probes for more information.
Additional affiliations
November 2019 - present
Yale University
Position
  • Researcher
September 2018 - October 2019
Yale University
Position
  • Researcher
November 2016 - August 2018
Yale University
Position
  • Research Associate
Education
November 2001 - September 2007
Technische Universität Kaiserslautern
Field of study
  • Physical Chemistry
October 1999 - November 2001

Publications

Publications (42)
Article
We describe a systematic method for the preparation and spectroscopic characterization of a CO2 molecule coordinated to an activated bisphenoidal nickel(I) compound containing a tetraazamacrocyclic ligand in the gas phase. The resulting complex was then structurally characterized by using mass-selected vibrational predissociation spectroscopy. The...
Article
Recent advances in gas phase ion chemistry, coupled with cryogenic ion vibrational predissociation spectroscopy, provide a powerful way to characterize the structures of small molecules bound to open coordination sites of organometallic compounds. Here we extend our previous measurements on the relatively weakly interacting CO2 molecule with a Ni(I...
Article
The heterogeneous reaction of N2O5 with sea spray aerosols yields the ClNO2 molecule, which is postulated to occur through water-mediated charge separation into NO3ˉ and NO2⁺ followed by association with Clˉ. Here we address an alternative mechanism where the attack by a halide ion can yield XNO2 by direct insertion in the presence of water. This w...
Article
Full-text available
We describe an instrumental configuration for the structural characterization of fragment ions generated by collisional dissociation of peptide ions in the typical MS2 scheme widely used for peptide sequencing. Structures are determined by comparing the vibrational band patterns displayed by cryogenically cooled ions with calculated spectra for can...
Article
The solution kinetics of a proton-coupled electron transfer reaction involving two-electron oxidation of a Ru compound with concomitant transfer of two protons to a quinone derivative have been interpreted to indicate the formation of a long-lived intermediate between the reactants. We characterize the ionic reactants, products, and an entrance cha...
Article
Photoredox catalysis using proton-coupled electron transfer (PCET) has emerged as a powerful method for bond transformations. We previously employed traditional chemical oxidants to achieve multiple-site concerted proton-electron transfer (MS-CPET) activation of a C–H bond in a proof-of-concept fluorenyl-benzoate substrate. As described here, photo...
Article
Hydroxy functionalization of cations in ionic liquids (ILs) can lead to formation of contacts between their OH groups [so-called (c–c) interactions]. One class of these linkages involves cooperatively enhanced hydrogen bonds to anionic partners that are sufficiently strong to overcome the repulsion between two positively charged centers. Herein, we...
Article
We address the cooperative hydrogen bonding interactions in play between the ionic constituents of ionic liquids (ILs) with particular attention to those involving the attractive interactions between two cations in the system 1-(2-hydroxyethyl)pyridinium tetrafluoroborate [HEPy][BF4]. This is accomplished by comparing the temperature-dependent line...
Article
We address the formation of hydrogen bonded domains among the cationic constituents of the ionic liquid (IL) 1‐(3‐hydroxypropyl)pyridinium tetrafluoroborate [HPPy][BF4] by means of cryogenic ion vibrational predissociation spectroscopy of cold (ca. 35 K) gas‐phase cluster ions and quantum chemistry. Specifically, analysis of the OH stretching bands...
Article
We address the formation of hydrogen bonded domains among the cationic constituents of the ionic liquid (IL) 1‐(3‐hydroxypropyl)pyridinium tetrafluoroborate [HPPy][BF4] by means of cryogenic ion vibrational predissociation spectroscopy of cold (ca. 35 K) gas‐phase cluster ions and quantum chemistry. Specifically, analysis of the OH stretching bands...
Article
We address the competition between intermolecular forces underlying the recent observation that ionic liquids (ILs) with a hydroxyl-functionalized cation can form domains with attractive interactions between the nominally repulsive positively charged constituents. Here we show that this behavior is present even in the isolated ternary (HEMIm+)2NTf2...
Article
Roll-over cyclometalation is a special case of cyclometalation. While in classical cyclometalation, C,H-activation (deprotonation or oxidative addition) has to occur at the ligand to result in a metallacycle, in roll-over cyclometalation the ligand in principle has the chance to undergo chelating coordination without cleavage of a C-H bond (e.g. κ²...
Article
Recent advances in the coupling of vibrational spectroscopy with mass spectrometry create new opportunities for the structural characterization of metabolites with great sensitivity. Previous studies have demonstrated this scheme on 300 K ions using very high power free electron lasers in the fingerprint region of the infrared. Here we extend the s...
Article
We report the vibrational spectra of the hydronium and methylammonium ions captured in the C3v binding pocket of the 18-crown-6 ether ionophore. Although the NH stretching bands of the CH3NH3 + ion are consistent with harmonic expectations, the OH stretching bands of H3O⁺ are surprisingly broad, appearing as a diffuse background absorption with lit...
Article
We report the vibrational spectra of the hydronium and methyl-ammonium ions captured in the C3v binding pocket of the 18-crown-6 ether ionophore. Although the NH stretching bands of the CH3NH3(+) ion are consistent with harmonic expectations, the OH stretching bands of H3O(+) are surprisingly broad, appearing as a diffuse background absorption with...
Article
This study elucidates structures, activation barriers and the gas phase reactivity of cationic ruthenium transfer hydrogenation catalysts of the structural type [(η6-cym)RuX(pympyr)]+. In these complexes, the central ruthenium(+II) ion is coordinated to a η6-bound p-cymene (η6-cym), a bidentate 2-R-4-(2-pyridinyl)pyrimidine ligand (pympyr) with R =...
Article
The synthesis of 2-substituted pyridinepyrimidine ligands and their complexation with arene ruthenium(II) chloride moieties is reported. Depending on the electronic and steric influence of the ligand, the catalysts undergo a CH activation by a roll-over cyclometallation. This process opens up the route to the catalytic transfer hydrogenation of ket...
Article
Formation of N-H and N-C bonds from functionalization of N2 is a potential route to utilization of this abundant resource. One of the key challenges is to make the products of N2 activation reactive enough to undergo further reactions under mild conditions. This paper explores the strategy of "alkali control," where the presence of an alkali metal...
Article
There is great interest in developing Mn water-splitting catalysts due to low cost, abundance, and relevance to the oxygen-evolving complex (OEC). Three ligands with highly donating pyridine alkoxide moieties, including "pyalkH" (2-(pyridin-2-yl)propan-2-ol), "py-dialkH2" (2,2'-(pyridine-2,6-diyl)bis(propan-2-ol)), and "bipy-alkH" (2-([2,2'-bipyrid...
Article
The FeMoco of nitrogenase is an iron-sulfur cluster with exceptional bond-reducing abilities. ENDOR studies have suggested that E4, the state that binds and reduces N2, contains bridging hydrides as part of the active-site iron-sulfide cluster. However, there are no examples of any isolable iron-sulfide cluster with a hydride, which would test the...
Article
A bimetallic catalyst system is presented that enables the decarboxylative cross-coupling of triflates with carboxylate salts at only 100 °C, which is 70 °C lower than with previous Cu/Pd-based systems. The new protocol allows the coupling of a broad range of aryl triflates with various substituted 2-nitrobenzoates in good to excellent yields. The...
Article
The strong temperature dependence of the I⁻∙(H2O)2 vibrational predissociation spectrum is traced to the intracluster dissociation of the ion-bound water dimer into independent water monomers that remain tethered to the ion. The thermodynamics of this process are determined using van't Hoff analysis of key features that quantify the relative popula...
Article
Full-text available
Two-color infrared multiple photon dissociation (2c-IR-MPD) spectroscopy with delayed pulses indicates a torsional isomerization in a "ligand-metal-chelate" complex [AgL1L2](+). Ab initio calculations reveal the torsional barrier as well as the change in vibrational frequencies and IR intensities along the isomerization pathway. The current approac...
Article
Ruthenium(II) complexes [(η6-cymene)RuCl(apypm)]BPh4 with bidentate 2-amino-4-(2-pyridinyl)pyrimidine (apypm) ligands catalyze the transfer hydrogenation of acetophenone. Their activities are strongly dependent on the substituent pattern of the pyrimidine ring. Complexes bearing a primary amino group in the 2-position of the pyrimidine ring do not...
Article
A series of bimetallic silyl halido cuprates consisting of the new tripodal silicon-based metalloligand [κ(3) N-Si(3,5-Me2 pz)3 Mo(CO)3 ](-) is presented (pz=pyrazolyl). This metalloligand is straightforwardly accessible by reacting the ambidentate ligand tris(3,5-dimethylpyrazolyl)silanide ({Si(3,5-Me2 pz)3 }(-) ) with [Mo(CO)3 (η(6) -toluene)]. T...
Article
Full-text available
Two Ag(I) ions, deprotonated 1-methyl-thymine (1MT-H)(-) and 1,3-dideaza-adenine (DDA), self-assemble in methanolic solution to a cationic [(Ag)2(1MT-H)(DDA)](+) complex as identified by electrospray ionization mass spectrometry. Assignment of vibrational bands and identification of the silver coordination pattern arise from comparison of one- and...
Article
Pyridinylazolato (N-N') ruthenium(II) complexes of the type [(N-N')RuCl(PMe3 )3 ] have been obtained in high yields by treating the corresponding functionalised azolylpyridines with [RuCl2 (PMe3 )4 ] in the presence of a base. (15) N NMR spectroscopy was used to elucidate the electronic influence of the substituents attached to the azolyl ring. The...
Article
Full-text available
The Schiff base compound 2,2'-{[(2-aminoethyl)imino]bis[2,1-ethanediyl-nitriloethylidyne]}bis-2-hydroxy-benzoic acid (H(4)L) as a proligand was prepared in situ from 3-formylsalicylic acid with tris(2-aminoethyl)amine (tren). The trinuclear 3d-4f metal complexes of this ligand {[Ln{Ni(H(2)L)(tren)}(2)](NO(3))(3)} (Ln = Gd, Dy, Er, Lu) could be obta...
Article
The Schiff base compound 2,2'-{[(2-aminoethyl)imino]bis[2,1-ethanediyl-nitriloethylidyne]}bis-2-hydroxy-benzoic acid (H(4)L) as a proligand was prepared in situ. This proligand has three potential coordination pockets which make it possible to accommodate from one to three metal ions allowing for the possible formation of mono-, di-, and trinuclear...
Article
The ruthenium-catalyzed hydroamidation of terminal alkynes has evolved to become a broadly applicable tool for the synthesis of enamides and enimides. Depending on the catalyst system employed, the reaction leads chemo-, regio-, and stereoselectively to a single diastereoisomer. Herein, we present a comprehensive mechanistic study of the ruthenium-...
Article
The complexation of alkali metal ions and the proton X+ (X = H, Li, Na, K. Rb, Cs) by beta-alanyl-L-histidine (carnosine, Car) was investigated by electrospray ionization mass spectrometry (ESI-MS) and MS/MS fragmentation studies. Collision-induced dissociation (CID) breakdown curves were recorded and the resulting apparent activation energies were...
Article
A Fourier-Transform-Ion-Cyclotron-Resonance mass spectrometer has been installed at the BESSY II storage ring. This unique setup enables to record soft X-ray absorption and magnetic circular dichroism spectra (XMCD) of mass-selected clusters in the photon energy range 200–1200 eV. The photoabsorption signal is obtained by recording the fragmentatio...
Article
A rational catalyst development based on mechanistic and spectroscopic investigations led to the discovery of a new protocol for catalytic hydroamidation reactions that draws on easily available ruthenium trichloride trihydrate (RuCl3⋅3 H2O) as the catalyst precursor instead of the previously employed, expensive bis(2-methylallyl)(1,5-cyclooctadien...

Questions

Question (1)
Question
I tried to attach Ag+ ions to the molecules and had a little success for small molecules like hexaphenylbenzene. Is there a way to extend this method to larger graphene precursors?

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Projects (3)
Project
Roll-over cyclometallation provides an anionic ligand from a neutral ligand without changing the coordination geometry at a catalytically active metal centre. We found activation of catalyts for transfer hydrogenation, reductive amination and C-C- coupling reactions resulting from this process.