Classification of the Mechanical Bonds

Abstract

The analysis of suit[2]-, suit [3]ane and tetrafould [2]-rotaxanes on the bases of calix[4]-arene with the help of the "mechanical disconnection operation" show that these structures possess only one mechanical bond, which is suggested to be called bi-, tri-and tetrafurcated one, respectively, since such structures bear two, three and four divergent mechanical entanglements. In the same time, introduction of the external bulky groups to these structures transforms such unique mechanical bonds into several single ones. There can be several different invariants which have only one mechanical bond, but possess different number of the intrinsic mechanical entanglements like, for example, in [2]-catenane and doubly braided [2]-catenane. The mechanical bond in the last case is proposed to be called the tight one. The constrictive bonds in carceplexes are classified as the spherical mechanical bonds. Thus, the whole classification of the mechanical bonds (together with the previously proposed ones), is presented.