Interaction of water and dichlorine in the gas phase: An investigation of H2O⋯Cl2 by rotational spectroscopy and ab initio calculations

Abstract

Ground-state rotational spectra of the seven isotopomers H2O⋯35Cl2, H2O⋯37Cl35Cl, H2O⋯35Cl37Cl, D2O⋯35Cl2, D2O⋯37Cl35Cl, HDO⋯35Cl2, and HDO⋯37Cl35Cl of the complex formed between water and dichlorine were observed by pulsed-jet, Fourier-transform microwave spectroscopy. Rotational constants B0 and C0, centrifugal distortion constants ΔJ and ΔJK, and Cl nuclear quadrupole coupling constants χaa(Clx) and {χbb(Clx)−χcc(Clx)}, where x=i (inner) or o (outer), were obtained via spectral analyses. The spectroscopic constants were interpreted, on the basis of models for the complex, to give the geometry, the binding strength, and the extent of inter- and intramolecular electron transfer on complex formation. The zero-point geometry is defined in terms of the effective values r(O⋯Cli)=2.8479(3) Å and φ=43.4(3)°, where φ is the angle made by the bisector of the HÔH angle with the O⋯Cl internuclear line. The intermolecular stretching force constant kσ=8.0(1) N m−1. Fractions δi=0.005(5) and δp=0.034(3) of an electron were estimated to be transferred from O to Cl and from Cli to Clo, respectively. The geometrical conclusions are supported by ab initio calculations at the aug-cc-pVDZ/MP2 level of theory, with good agreement for φ and r(O⋯Cli). A comparison of the properties of H2O⋯Cl2 with those of H2O⋯HCl provides evidence in support of a recent proposal of a halogen bond B⋯XY that is the analog of the hydrogen bond B⋯HX, where X and Y are halogen atoms.

The Interaction of Water and Dibromine in the Gas Phase: An Investigation of the Complex H2O⋅⋅⋅Br2 by Rotational Spectroscopy and Ab Initio Calculations

“…A similar approach to that described in the preceding paragraph has now been applied to six complexes of the type H 2 O ¥¥¥ XY, namely those in which XY is F 2 , [6,7] Cl 2 , [9] Br 2 , BrCl, [10] ClF [7,8] and ICl. [11] It is timely to compare the properties of the complexes determined in this way.…”

“…So far, comparisons of the properties of the two series for a range of Lewis bases B have revealed a parallelism that suggests it is appropriate to describe this interaction B ¥¥¥ XY as a halogen bond. In the specific series H 2 O ¥¥¥ XY, the examples where XY is F 2 , [6,7] ClF, [7,8] Cl 2 , [9] BrCl [10] and ICl [11] have already been examined by our combined experimental/computational approach. The present results for H 2 How does this vary with atom X and how does it vary when X is held constant and Y is changed?…”

“…c aa (Br x ) c e zz (Br x ) hP 2 (cosb)i (11) In Equation (11), b is the instantaneous angle between the a inertia axis and the Br 2 internuclear axis z, P 2 is the second Legendre coefficient and the average is over the zero-point motion of the complex. The use of an exact equality in Equation (11) implies the assumption that the d(Br x ) defined in Equations (8) and (9) are independent of the angle f (see Figure 1). …”

Magnitude and Origin of the Attraction and Directionality of the Halogen Bonds of the Complexes of C6F5X and C6H5X (X=I, Br, Cl and F) with Pyridine

“…[49][50][51] The structures of complexes formed by halogen bonds in the gas phase have been studied by microwave spectroscopy. [30][31][32] Halogen bonds in crystals have been studied by X-ray diffraction and by statistical analysis of the crystal structure database. [33][34][35][36][37][38][39][40][41] The NMR and other spectroscopic measurements of halogen bonds have also been reported.…”

Halogen Bonding with Dihalogens and Interhalogens

“…In a recent paper, they investigate the H 2 O· · ·Cl 2 complex, noting that it probably plays a role in both the ozone depletion cycle (through the reaction HOCl + HCl → Cl 2 + H 2 O) and in water treatment through the reverse reaction to form hypochlorous acid [160]. They examined seven isotopomers resulting from various combinations of deuterium and 35 Cl/ 37 Cl labeled complexes by pulsed-jet microwave spectroscopy.…”