A bistable [2]pseudorotaxane 1⊂CBPQT•4PF6 and a bistable [2]rotaxane 2•4PF6 have been synthesised to measure the height of an electrostatic barrier produced by double molecular oxidation (0 to +2). Both systems...

This research investigates whether parental role and gender are associated with career advancement for professional female and male auditors employed by international audit firms in Denmark. Management at four levels, from partner to lower level non-management employee, are examined to determine whether a relationship holds between being a parent and gender. We find that more parents achieve advancement to higher levels of employment than non-parents. However, mothers are significantly disadvantaged relative to fathers in achieving senior levels of employment. There is no significant difference in the likelihood of career advancement between female and male auditors that are not parents implied by a lack of significant results for the gender variable in the regression analyses. Years of experience also significantly explains career advancement in the organization while age is significantly correlated with experience of the auditor.

We have investigated and quantified the role that the glycol chain length has on the strength of the noncovalent bonding interactions taking place between cyclobis(paraquat-p-phenylene) (CBPQT) and five different monopyrrolo-tetrathiafulvalene (MPTTF) derivatives that only differ in the length of the N-substituted glycol chain. The MPTTF derivatives were used to form [2]pseudorotaxanes by mixing them with CBPQT. The binding constants (K) associated with the complexation process leading to the formation of the [2]pseudorotaxanes were obtained using the UV-vis-NIR dilution method and the [2]pseudorotaxanes were characterized structurally using H NMR spectroscopy. These experimental investigations clearly indicate that the glycol chains provide additional stability to the [2]pseudorotaxanes findings that were further supported by density functional theory (DFT) studies. The DFT calculated superstructure of the [2]pseudorotaxane 3⊂CBPQT reveal that [C-H···O] hydrogen bonding interactions between the acidic α-H protons in CBPQT and the oxygen atoms present in the glycol chain can take place on the exterior of the [2]pseudorotaxane. However, the length of the glycol chain is of paramount importance and the present studies show that the first and second oxygen atom in the [2]pseudorotaxanes 2-5⊂CBPQT are engaged in [C-H···O] hydrogen bonding interactions with CBPQT, whereas the third and fourth oxygen atoms are not.

The switching speed of a bistable [2]rotaxane upon oxidation is found to be increased in the presence of added salts.