Template effect three-dimensional

The Three-Dimensional Template Effect, Supramolecular Chemistry and Molecular Topology... 

What should we do to observe a three-dimensional template effect First, we should choose a reaction type that we know to be effective for the formation of macrocyclic ligands and extend the methodology to a kinetically inert cP or d6 metal centre. Let us reconsider the reaction, that we first encountered in Fig. 6-11. In this reaction, a dioximato complex reacted with BF3 to give the nickel(n) complex of a dianionic macrocycle (Fig. 7-1). 

The synthesis of the first doubly interlocked [2]-catenane, based on the three-dimensional template effect of Cu+I, has been completed in principle, helices containing an odd number of metal centers lead to even numbered crossing [2]-catenanes [94JA375]. 

Transition metals have been used as assembling and templating species in a variety of processes [1]. The three-dimensional template effect of one or two copper(I) centres has extensively been used to construct topologically non-trivial molecules like catenanes and knots [2]. 

Sauvage et al. introduced the first template directed catenane synthesis using transition metals. Transition metal ions have the specific capability to coordinate molecules with suitable functional groups. This orthogonalisation is responsible for the three-dimensional template effect [28]. 

ABSTRACT. Knots and interlaced designs have been part of human artistry and culture since the earliest times. In chemistry, knots have been the focus of theoretical investigations for several decades. In pandlel, a few experimental approaches have been attempted by synthetic chemists. Until recent years, the only preparative routes pursued used the tools of classical organic chemistry. Despite their intellectual elegance, they have not succeeded. By taking advantage of the three-dimensional template effect of a transition metal (copper I), it has recently been possible to interlace two molecular threads prior to cyclisation and formation of a dimetallic trefoil knot. The demetallated knotted molecule and its di-copper(I) precursor have been fully characterized and studied. The X-ray structure of the dimetallic trefoil knot has been solved. It confirms the topology of the system. 

---