Organometallic Rotaxanes with a Triazole Group in the Axle Component and Their Behavior as Ligands of Pt^II Complexes

Abstract

Two ferrocenylmethyl ammonium salts were used as axle components of pseudorotaxanes with dibenzo[24]crown-8. The pseudorotaxane with an alkyne terminal group in the axle component underwent a Cu-catalyzed Huisgen coupling reaction (click reaction) with an alkyl azide to afford cationic [2]rotaxanes with a triazole group in the axle molecule. The rotaxane reacted with Ac(2) O to produce neutral rotaxanes with an amide group in the axle component. Both cationic and neutral rotaxanes were treated with K[PtCl(3)(CH(2)=CH(2))] to form the Pt(II)-containing rotaxanes.

Cationic and Neutral Rotaxanes Having Different Functional Groups in the Axle Molecule and Their Coordination to PtII

“…Scheme summarizes the structure of the cationic and neutral axle molecule, [ 1 ] + PF 6 − and 2 , respectively, and their [2]rotaxanes with dibenzo[24]crown‐8 (DB24C8), used in this study. A Cu I ‐aided click reaction of the alkynyl compound having a terminal ferrocenylmethyl group with the azide having a 3,5‐dimethylphenyl group produces [ 1 ] + PF 6 − , and the reaction in the presence of DB24C8 affords the corresponding [2]rotaxane [ 1 (DB24C8)] + PF 6 − . The lower yield of [ 1 ] + PF 6 − (49 %) than that of [ 1 (DB24C8)] + PF 6 − (92 %) can be attributed to partial deactivation of the Cu catalyst by the strong interaction with the ammonium group.…”

“…Rotaxanes composed of crown ether and an axle molecule containing an ammonium group were reported to undergo acetylation to release the macrocycle component from the hydrogen bonding . The reaction of acetyl chloride with [ 1 (DB24C8)] + PF 6 − proceeds smoothly to yield the neutral rotaxane 2 (DB24C8) . The neutral axle compound 2 is obtained by initial acetylation of the alkynyl precursor followed by the click reaction with an azide having a bulky 3,5‐dimethylphenyl end group.…”

“…Usually, the coordination of a metal to a macrocycle or a thread component prevents the macrocycle from shuttling along the axle and locks the rotaxane structure, similar to the cis – trans isomerism of an olefin group of the axle component . We previously reported the synthesis of cationic and neutral rotaxanes having a triazole group in the axle component and their complex formation with a Pt‐ethylene fragment . Further studies of the rotaxanes by NMR spectroscopy revealed details of their co‐conformation.…”

Rotaxanes and pseudorotaxanes with threads containing viologen units

“…Having in view a multitude of works dealing with rotaxanes [101][102][103] and pseudorotaxanes, 104,105 as well as works concerning these both structures, 106,107 in the present paper only selected examples are described. Among a great number of applications of rotaxanes, such as construction of molecular devices or sensors, one should point out the possibility to use these species in the design of molecular machines.…”

Silica Nanospheres Functionalized by Ferrocene-containing [2]Rotaxane

“…4 (C 2 HN 3 )(CH 2 ) 3 Si(OEt) 3 )]PF 6 (3), similarly to our previous report (eq 1). The product was characterized based on comparison of spectroscopic data with those having similar structures, 15 as shown below. The HR-ESI mass spectrum of 3 shows a peak at m/z 1097.4961, assigned to the cationic (4).…”