The molecular structure of thiazole, determined by the combined analysis of gas-phase electron diffraction (GED) data and rotational constants and by abinitio calculations

Abstract

The molecular structure of thiazole has been determined by the joint analysis of data obtained from gas-phase electron diffraction (GED), microwave (MW) spectroscopy and abinitio molecular orbital calculations. The combined approach, making use of the SARACEN method, has led to a very precise structure in which all independent geometric parameters are well defined, and the quoted uncertainties reflect the true accuracy of the measurements. The ground-state average (≡r_α^° or r_z) structural parameters obtained in the combined study of thiazole were; r[S(1)–C(2)]=172.37(11) pm, r[S(1)–C(5)]=171.38(13) pm, r[C(2)–N(3)]=131.0(2) pm, r[C(4)–C(5)] pm=136.90(19) pm, r[N(3)–C(4)]=137.2(2) pm, r[C(2)–H(6)]=109.8(4) pm, r[C(4)–H(7)]=109.9(4) pm, r[C(5)–H(8)]=109.7(4) pm, C(2)–S(1)–C(5)=89.41(4)°, S(1)–C(2)–N(3)=115.16(6)°, S(1)–C(5)–C(4)=109.52(8)°, C(2)–N(3)–C(4)=109.97(9)°, N(3)–C(4)–C(5)=115.95(11)°, S(1)–C(2)–H(6)=120.7(2)°, C(5)–C(4)–H(7)=125.0(4)°, S(1)–C(5)–H(8)=121.7(2)°.