文摘
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, 螖J and 螖JK, and nuclear quadrupole coupling constants, 蠂aa(Au), 蠂bb(Au) 鈥?蠂cc(Au), 蠂aa(I), and 蠂bb(I) 鈥?蠂cc(I), are measured for three isotopologues of C2H2路路路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 蟺-orbitals of ethyne. On formation of the complex, the C鈮 bond of ethyne extends by 0.032(4) 脜 relative to r(C鈮) in isolated ethyne when the respective r0 geometries are compared. The geometry of ethyne distorts such that 鈭?*鈥擟鈥擧) (where * indicates the midpoint of the C鈮 bond) is 194.7(12)掳 in the r0 geometry of C2H2路路路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鈥?. The 蠂aa(Au) and 蠂aa(I) nuclear quadrupole coupling constants of AuI and also the Au鈥擨 bond length change significantly on formation of the complex consistent with the strong interaction calculated to occur between C2H2 and AuI.