title: An Isolated Complex of Ethyne and Gold Iodide Characterized by Broadband Rotational Spectroscopy and Ab initio Calculations.
abstract: A molecular complex of C2H2 and AuI has been generated and isolated in the gas phase through laser ablation of a gold surface in the presence of an expanding sample containing small percentages of C2H2 and CF3I in a buffer gas of argon. Rotational, B0, centrifugal distortion, ΔJ and ΔJK, and nuclear quadrupole coupling constants, χaa(Au), χbb(Au) - χcc(Au), χaa(I), and χbb(I) - χcc(I), are measured for three isotopologues of C2H2···AuI through broadband rotational spectroscopy. The complex is C2v and T-shaped with C2H2 coordinating to the gold atom via donation of electrons from the π-orbitals of ethyne. On formation of the complex, the C≡C bond of ethyne extends by 0.032(4) Å relative to r(C≡C) in isolated ethyne when the respective r0 geometries are compared. The geometry of ethyne distorts such that ∠(*-C-H) (where * indicates the midpoint of the C≡C bond) is 194.7(12)° in the r0 geometry of C2H2···AuI. Ab initio calculations at the CCSD(T)(F12*)/AVTZ level are consistent with the experimentally determined geometry and further allow calculation of the dissociation energy (De) as 136 kJ mol(-1). The χaa(Au) and χaa(I) nuclear quadrupole coupling constants of AuI and also the Au-I bond length change significantly on formation of the complex consistent with the strong interaction calculated to occur between C2H2 and AuI.
authors: School of Chemistry, Bedson Building, Newcastle University , Newcastle upon Tyne, Tyne and Wear, NE1 7RU, U.K.
authors: John C
authors: JC
authors: Mullaney
authors: School of Chemistry, Bedson Building, Newcastle University , Newcastle upon Tyne, Tyne and Wear, NE1 7RU, U.K.
authors: Susanna L
authors: SL
authors: Stephens
authors: School of Chemistry, Bedson Building, Newcastle University , Newcastle upon Tyne, Tyne and Wear, NE1 7RU, U.K.
authors: Daniel P
authors: DP
authors: Zaleski
authors: School of Chemistry, Bedson Building, Newcastle University , Newcastle upon Tyne, Tyne and Wear, NE1 7RU, U.K.
authors: Matthew J
authors: MJ
authors: Sprawling
authors: School of Chemistry, University of Bristol , Bristol BS8 1TS, U.K.
authors: David P
authors: DP
authors: Tew
authors: School of Chemistry, Bedson Building, Newcastle University , Newcastle upon Tyne, Tyne and Wear, NE1 7RU, U.K.
authors: Nicholas R
authors: NR
authors: Walker
authors: School of Chemistry, University of Bristol , Bristol BS8 1TS, U.K.
authors: Anthony C
authors: AC
authors: Legon