Menshutkin's {(Arene)·nSbX₃} Molecular CompoundsExploring the Correlation between Crystal Structures and Nuclear Quadrupole Resonance Spectra

Abstract

By use of data from the literature to assign 35Cl, 81Br, 121Sb, and 123Sb nuclear quadrupole resonance (NQR) frequencies to particular atoms, an attempt is made to correlate crystal structures of a number of {(arene)·nSbX3} (X = Cl, Br) Menshutkin molecular compounds with their NQR spectra. Comparing NQR spectra of crystalline neat SbX3 (X = Cl, Br) with those of the molecular compounds shows well-established effects due to the perturbations introduced by changes in the detailed structures of the networks of SbX3 moieties and in the interactions of Sb atoms with the arene moieties. NQR spectra are much more sensitive in this regard than the changes in interatomic distances that are among the main quantitative outcomes of crystal structure analysis. Although a qualitative pattern can be discerned that associates the frequency of the 35Cl NQR spectra with the different structural roles of the crystallographically independent chlorines, it has not been possible to identify particular interactions with the differences found in the NQR frequencies. Generalizations based on NQR spectra do not appear currently achievable, and it seems likely that the spectra of the various molecular compounds will require explanation on an individual basis.

NQR parameters of complexes and polarizability effect

“…Narrow series I–XXXVI of various complexes taken from the literature are given in Tables . The interpreting of NQR spectra on occasion involves difficulties.…”

Pseudo‐One‐Coordinate Tetrylenium Salts Bearing a Bulky Carbazolyl Substituent

“…The geometry of the carbazolyl substituent enables Menshutkin‐type interactions (interactions between main‐group elements and arenes, observed first by Smith et al. but systematically studied by Menshutkin in the beginning of the 20th century) . In 6 Ge only one arene is interacting with the Ge atom, while the other arene is bent away, revealing the influence of the Ge lone pair.…”

“…After filtration, concentration and layering with pentane, large crystals of the desired salts The geometry of the carbazolyl substituent enables Menshutkin-type interactions (interactionsb etween main-group elements and arenes, observed first by Smith et al but systematically studied by Menshutkin in the beginningo ft he 20th century). [30,31] In 6Ge only one arene is interacting with the Ge atom, while the other arene is bent away,r evealing the influence of the Ge lone pair.C ontrastingt his, in all cations[ 7E] + , both arenes are essentially coplanara nd donating equally towards the tetrel centre. This is also indicated by QTAIM as there is ab ondingp ath between the ipso-C atoms of the arene substituents and the heavy tetrels.A tt he bond critical point, the electron density and the Laplacian of the electron density assumev alues (averaged, [RGe] 1:0 .0257, r 2 :0 .0483; [RSn] 1:0 .0217, r 2 :0 .0485;[ RPb] 1:0 .0211, r 2 :0 .0560) considerably highert han in weak interactions (benzene stacking 1: 0.0073, r 2 :0 .0049,a cetylene dimer 1:0 .0067, r 2 0.0047), but in the same order of magnitude as hydrogen bonds (H 2 O dimer: 1:0 .0219, r 2 :0 .0396, HOAc dimer 1:0 .0425, r 2 : 0.0335).…”