Gas-Phase Structure of a π-Allyl−Palladium Complex: Efficient Infrared Spectroscopy in a 7 T Fourier Transform Mass Spectrometer

Citations Over TimeTop 10% of 2007 papers

Abstract

The performance of infrared (IR) spectroscopy of gas-phase ions in a commercially available 7 T Fourier transform ion cyclotron resonance mass spectrometer has been characterized. A pi-allyl-palladium reactive intermediate, [(pi-allyl)Pd(P(C6H5)3)2]+, involved in the catalytic allylation of amine is studied. A solution of this transition metal complex is electrosprayed, and the IR multiple photon dissociation (IRMPD) spectrum of the mass-selected ions is recorded in two spectral ranges. The fingerprint spectrum (650-1550 cm(-1)) is recorded using the Orsay free-electron laser, and the dependence of the IRMPD efficiency on laser power and irradiation time is characterized. The DFT-calculated IR absorption spectrum of the [(pi-allyl)Pd(P(C6H5)3)2]+ complex shows good agreement with the experimental spectrum. The pi-interaction between the palladium and the allyl moiety is reflected by the assignment of the IRMPD bands, and the observed allylic CH2 wagging modes appear to form a sensitive probe for the pi-interaction strength in metal-pi-allyl complexes. This spectral assignment is further supported by the analysis of the different IRMPD photofragmentation patterns observed at different photon energies, which are found to result from wavelength-specific photofragmentations. Nine peaks are well-resolved in the experimental spectrum, for which the bandwidth (fwhm) is on the order of 15 cm(-1). Resonances with a calculated IR intensity of 5 km/mol or larger are shown to be amenable for IRMPD, indicating an excellent sensitivity of our new experimental setup. Finally, the IR spectrum has also been recorded in the CH stretching region (2950-3150 cm(-1)) using a tabletop IR optical parametric oscillator/amplifier (OPO/OPA) laser source.

Related Papers

• → 2D FT-ICR MS of Calmodulin: A Top-Down and Bottom-Up Approach(2016)39 cited
• → Combined infrared multiphoton dissociation and electron‐capture dissociation using co‐linear and overlapping beams in Fourier transform ion cyclotron resonance mass spectrometry(2006)27 cited
• → Radical‐directed dissociation of peptides and proteins by infrared multiphoton dissociation and sustained off‐resonance irradiation collision‐induced dissociation with Fourier transform ion cyclotron resonance mass spectrometry(2014)10 cited
• → Infrared Multiphoton Dissociation Spectroscopic Analysis of Peptides and Oligosaccharides by Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry with a Midinfrared Free-Electron Laser(2006)22 cited
• Ion Structure and Energetics in the Gas Phase Characterized Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry(2014)