Infrared Spectroscopy of Au(Acetylene)n + Complexes in the Gas Phase
Au(C2H2)n + (n = 1–6) ion–molecule complexes are produced in the gas phase via pulsed laser vaporization in a supersonic expansion of acetylene and argon. Cations are size selected and studied with infrared photodissociation spectroscopy in the C–H stretching region (3000–3500 cm−1). Insight into the structure and bonding of these species is obtained from the number of infrared active bands, their relative intensities and their frequency positions. Density functional theory calculations provide structures for these complexes and predicted spectra are compared to the experiment. The combined data indicate that gold cation has a primary coordination number of two with respect to acetylene binding, and a secondary coordination sphere that is completed with a third ligand. Larger complexes (n = 4–6) are formed by solvation of the Au(C2H2)3 + core ion with acetylene, in a pattern like that seen previously for Cu(C2H2)n + complexes. Small differences in the spectra between corresponding copper and gold cation complexes are explained by theory, but only when relativistic corrections are included for the gold complexes.
KeywordsOrganometallic ions Mass spectrometry Photodissociation Infrared spectroscopy
We acknowledge generous support for this work from the Air Force Office of Scientific Research through grant no. FA9550-15-1-0088. ADB wishes to acknowledge salary support from the National Science Foundation through HBCU-UP Award No. 1505095.
- 1.Heck RF (1974) Organotransition metal chemistry. Academic Press, New YorkGoogle Scholar
- 2.Huheey JE, Keiter EA, Keiter RL (1993) Inorganic chemistry principles of structure and reactivity. Harper Collins, New YorkGoogle Scholar
- 3.Crabtree RH (2009) The Organometallic chemistry of the transition metals. 5th edn, Wiley, HobokenGoogle Scholar
- 6.Boor J (1979) Ziegler-Natta catalysis and polymerization. Academic Press, New YorkGoogle Scholar
- 9.Bertini I, Gray HB, Stiefel EI, Valentine JS (2007) Biological inorganic chemistry: structure and reactivity. University Science Books, SausalitoGoogle Scholar
- 16.Freiser BS (ed) (1996) Organometallic ion chemistry. Kluwer, DordrechtGoogle Scholar
- 44.Nakamoto K (1997) Infrared and Raman spectra of inorganic and coordinated compounds, 5th edn. Wiley, New YorkGoogle Scholar
- 49.Dewar MJS (1951) A review of the π-complex theory. Bull Soc Chim Fr C71–C79,Google Scholar
- 50.Chatt J, Duncanson LA (1953) Olefin co-ordination compounds. III. Infrared spectra and structure: attempted preparation of acetylene compounds. J Chem Soc 2939–2947Google Scholar
- 60.Neese F (2012) The ORCA program system. Wiley Interdis Rev 2(1):73–78Google Scholar
- 66.Shimanouchi T (2003) Molecular Vibrational Frequencies, NIST Chemistry WebBook, NIST Standard Reference Database Number 69. In: Linstrom PJ, Mallard WG (eds) National Institute of Standards and Technology, Gaithersburg, p 20899Google Scholar