Microwave spectrum and structure of the (CO₂)₂N₂O complex

Abstract

The structure of the weakly bound complex (CO₂)₂N₂O has been determined. The spectra of seven isotopic species have been measured by pulsed nozzle Fourier transform microwave spectroscopy. The rotational constants for the normal species are A = 1597.458(3) MHz, B = 1232.969(2)MHz and C = 831.095(1)MHz. The structure resembles a cylinder with the three monomers roughly parallel to each other and is similar to the observed structures of (CO₂)₂OCS and (OCS)₂CO₂. The CC distance is 3.521(9) Å, and the CN distances are 3.427(9) Å and 3.638(8) Å. The dipole moment components for the normal species are μ_a = 0.16(4) D, μ_b = 0.14(5) D and μ_c = 0.130(2) D. The total dipole moment is 0.25(4) D. The structure of the complex is predicted quite well with a semi-empirical model that uses distributed multipole moments to represent the electrostatic charge distribution and atom—atom terms to describe dispersion and repulsion.