Examining transition metal hydrosulfides: The pure rotational spectrum of ZnSH (X̃2A′)

Abstract

The pure rotational spectrum of the ZnSH ((X) over tilde (2)A') radical has been measured using millimeter-wave direct absorption and Fourier transform microwave (FTMW) methods across the frequency range 18-468 GHz. This work is the first gas-phase detection of ZnSH by any spectroscopic technique. Spectra of the (ZnSH)-Zn-66, (ZnSH)-Zn-68, and (ZnSD)-Zn-64 isotopologues were also recorded. In the mm-wave study, ZnSH was synthesized in a DC discharge by the reaction of zinc vapor, generated by a Broidatype oven, with H2S; for FTMW measurements, the radical was made in a supersonic jet expansion by the same reactants but utilizing a discharge-assisted laser ablation source. Between 7 and 9 rotational transitions were recorded for each isotopologue. Asymmetry components with K-a = 0 through 6 were typically measured in the mm-wave region, each split into spin-rotation doublets. In the FTMW spectra, hyperfine interactions were also resolved, arising from the hydrogen or deuterium nuclear spins of I = 1/2 or I = 1, respectively. The data were analyzed using an asymmetric top Hamiltonian, and rotational, spin-rotation, and magnetic hyperfine parameters were determined for ZnSH, as well as the quadrupole coupling constant for ZnSD. The observed spectra clearly indicate that ZnSH has a bent geometry. The r(m)((1)) structure was determined to be r(Zn-S) = 2.213(5) angstrom, r(S-H) = 1.351(3) angstrom, and theta(Zn-S-H) = 90.6(1)degrees, suggesting that the bonding occurs primarily through sulfur p orbitals, analogous to H2S. The hyperfine constants indicate that the unpaired electron in ZnSH primarily resides on the zinc nucleus. Published by AIP Publishing.