149704-55-2Relevant academic research and scientific papers
Quantitative conformational study of redox-active [2]rotaxanes, part 1: Methodology and application to a model [2]rotaxane
Altobello, Silvano,Nikitin, Kirill,Stolarczyk, Jacek K.,Lestini, Elena,Fitzmaurice, Donald
, p. 1107 - 1116 (2008)
This paper reports a novel methodology for the conformational analysis of [2]rotaxanes. It combines NMR spectroscopic (COSY, NOESY and the recently reported paramagnetic line-broadening and suppression technique) and electrochemical techniques to enable a quantitative analysis of the co-conformations of interlocked molecules and the conformations of their components. This methodology was used to study a model [2]rotaxane in solution. This [2]rotaxane consists of an axle that incorporates an electronpoor, doubly positively charged viologen that threads an electron-rich crown ether. It has been shown that the axle of the [2]rotaxane in its dicationic state adopts a folded conformation in solution and the crown ether is localised at the viologen moiety. Following a oneelectron reduction of viologen, the paramagnetic radical cation of the [2]rotaxane retains its folded conformation in solution. The data also demonstrate that in the radical cation the crown ether remains localised at the viologen, despite its reduced affinity for the singly reduced viologen. The combined quantitative NMR spectroscopic and electrochemical characterisation of the electromechanical function of the model [2]rotaxane in solution provides an important reference point for the study of switching in structurally related bistable [2]rotaxanes, which is the subject of the second part of this work.
Chloride anion triggered motion in a bis-imidazolium rotaxane
Serpell, Christopher J.,Chall, Ricky,Thompson, Amber L.,Beer, Paul D.
supporting information; experimental part, p. 12052 - 12055 (2012/01/14)
We report the first bis-imidazolium-containing rotaxane, synthesised via anion templated self-assembly. Its co-conformation is controlled by a chloride anion recognition mechanism, thus demonstrating the viability of this protocol as a stimulus for shuttl
The rearrangement of N-triarylmethyl anilines to their p-triarylmethyl derivatives
Siskos, Michael G.,Tzerpos, Nikolaos I.,Zarkadis, Antonios K.
, p. 759 - 768 (2007/10/03)
The N-triarylmethyl anilines Ph3C-NHAr (Ar = Ph, o-Me-C6H4, m-Me-C6H4, p-Me-C6H4, p-O2N-C6H4, p-Ph3C-C6H4) and Ar'3C-NHPh tBu-C6H4)3C> prepared by the reaction of Ph3C-Cl with anilines ArNH2 and of the corresponding chlorides Ar'3C-Cl with aniline (at 50-100 deg C), undergo a Hoffmann-Martius rearrangement to p-triarylmethyl derivatives (i.e., p-Ar'3C-C6H4-NH2 for Ar = Ph) when they are heated (ca. 185 deg C) with equimolar amounts of PhNH3(1+)Cl(1-).The latter catalyses the rearrangement probably through the formation of the instable anilinium salt Ar'3C-NH2Ar(1+)Cl(1-) that serves as a Ar'3C(1+) ion source.Ar'3C(1+) in a second step (electrophilic aromatic substitution) leads with excess of ArNH2 to p-substituted derivatives (e.g. p-Ar'3C-C6H4-NH2).A free radical mechanism, resonable in view of the high temperatures used (ca. 185 deg C), could be excluded; Ar'3C-NHAr undergoes homolysis of the C-N bond to Ar'3C. radicals at temperatures higher than 200 deg C, a fact which was established using ESR spectroscopy and product analysis.
New Triarylmethyl Derivatives: "Blocking Groups" for Rotaxanes and Polyrotaxanes
Gibson, Harry W.,Lee, Sang-Hun,Engen, Paul T.,Lecavalier, Pierre,Sze, Jean,et al.
, p. 3748 - 3756 (2007/10/02)
Five triarylcarbinols (8, three new compounds) were synthesized.Using carbanion chemistry the triarylmethanes (13, five new compounds) made by formic acid reduction of 8 were converted to the ω,ω,ω-triarylalkanols (15, three new compounds) and thence to the chloro (17) and iodo (18) derivatives (five new compounds).Via carbocation chemistry p-(triarylmethyl)phenols (20, two new compounds) and aniline (21, new compound) were produced.Alkylation of 20 yielded alcohol (22), benzylic bromide (23), and carboxy (25) functionalized derivatives.The alcohol, halide, phenol, aniline, and carboxylic acid functionalized triarylmethane compounds are suitable end blocking groups for rotaxanes and polyrotaxanes.
