Rare and Diverse Binding Modes Introduced through Mechanical Bonding

Abstract

Any which way, but not loose: A range of diverse noncovalent binding interactions are observed with a [2]rotaxane (see structure) and a [2]catenane that are not found with similar but not mechanically interlocked fragments. (C (macrocycle) turquoise, other C atoms yellow, O red, N blue, H gray, F green, S orange.)

The btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] binding motif: a new versatile terdentate ligand for supramolecular and coordination chemistry

“…[1][2][3][4][5][6][7] Chauvin et al have proposed the use of Cs 3 [Ln(dpa) 3 ] complexes as secondary standards for luminescent quantum yield determination. 8,9 Dpa ligands have also been studied for their interactions with transition metal ions, 10 and in particular amide derivatives of dpa have been studied extensively, including for use in the formation of transition metal-containing interlocked systems, [11][12][13] as a ligand in Cu(II)-promoted hydroxylation of THF 14 as well as coordination chemistry with Ln(III) ions. 15 Our own research group has recently employed such amide derivatives of dpa in the formation of highly symmetrical and chiral luminescent bundles, 16 helicates 17 and half-helicates 18 templated via Ln(III)-directed self-assembly.…”

Ring closing metathesis employing organometallic substrates and the templated synthesis of macrocycles

“…Leigh et al have recently published the Pd tem- [37,38]. plated synthesis of catenanes [39] and rotaxanes using RCM [40,41].…”

Properties and emerging applications of mechanically interlocked ligands

“…5). 19 Coordination of pyridine 11 to Pd complex [Pd(10)(MeCN)] produced threaded complex [Pd (10) (11)] which was subsequently trapped by reaction with an isocyanate to give rotaxane Pd complex [Pd (12)]. Heating [Pd (12)] in the presence of Mg(OH) 2 resulted in the cyclisation of the urethane units to produce [Pd (13)].…”

“…However, similarly to Sauvage's report in the case of catenane 3, Leigh and co-workers have demonstrated that the enforced association of convergent binding sites within a rotaxane can give rise to complexes that are not accessible in the case of the corresponding non-interlocked ligands. 11 More recently, we have demonstrated that the active template Cu-mediated alkyne-azide cycloaddition (AT-CuAAC) 12 approach to rotaxanes can be used to generate very hindered interlocked molecules 13 to the point where this unusual environment can stabilise a reactive Cu I -organometallic species; when N i Pr 2 Et is employed to accelerate the AT-CuAAC reaction, the isolated product is not the expected rotaxane, but interlocked Cu I -triazolide [Cu (8)] intermediate of the CuAAC reaction ( Fig. 3).…”