Inter- and intramolecular electronic transfer on formation of H3P···ICl as determined by rotational spectroscopy

Rotational spectra and properties of complexes B⋯ICF3 (B = Kr or CO) and a comparison of the efficacy of ICl and ICF3 as iodine donors in halogen bond formation

“…On the other hand, the majority of gas-phase investigations so far have involved the rotational spectroscopy of homo-and hetero-nuclear dihalogen molecules XY = F 2 , ClF, Cl 2 , BrCl, Br 2 , or ICl as the halogen-atom donor (or electron acceptor) interacting with a wide variety of simple Lewis bases as the halogen-bond acceptor (or electron donor). [2][3][4][6][7][8][9][10][11][12][13][14][15] The systematic variation of B and XY revealed patterns among the various properties so determined and these patterns have led to several generalisations, among which are included some rules for accounting for angular geometry (the relative orientation of the two subunits), an assignment of electrophilicities of dihalogens XY and a simple relationship between the distance r(Z· · ·X) and the sum σ (Z) + σ (X) of the van der Waals radii of the acceptor atom Z of B and the halogen atom X. [2][3][4]19 It was found that the behaviour of the halogen bond in the B· · ·XY series is redolent of that of the hydrogen bond in the corresponding series B· · ·HX, suggesting a strong parallelism between halogen and hydrogen bonds; such a parallelism was also noted in the solid state.…”

“…The gas-phase investigations of the iodine bond have so far been restricted to complexes B· · ·ICl, in which ICl acts as the iodine donor. [6][7][8][9][10][11][12][13][14][15] The molecule I−CF 3 provides a bridge between solid-state investigations involving I−C 6 F 4 −I or I−(CF 2 ) n −I and the gas-phase studies of B· · ·ICl. Presumably, the electron-withdrawing power of the CF 3 group is less than that of a Cl atom and will lead to complexes B· · ·ICF 3 that are less strongly bound than B· · ·ICl, for a given B.…”

Halogen Bonding with Phosphine: Evidence for Mulliken Inner Complexes and the Importance of Relaxation Energy

“…This is particularly striking in the H 3 P· · · ClF case, where the component due to induction contributes almost as much as that from electrostatic effects. It is noted that all three of these complexes exhibit the above effects to a greater degree than H 3 P· · · ICl, where experimentally an electron transfer of 0.144 e has been obtained, 35 indicating relatively significant charge transfer.…”

The van der Waals potential energy surfaces and structures of He–ICl and Ne–ICl clusters

“…On the one hand, the linear form is adopted for Rg-ClF ͑RgϭHe, Ar, Kr͒, [6][7][8] Ar-ICl, 9 Ar-I 2 , 10 and Ne-I 2 ͑Refs. 11 and 12͒ complexes.…”