Knots topology

A comparison between the two isomers 86 and 87 produced strong evidence for the knotted topology of 86. Both compounds have identical mass spectra (FAB) molecular peaks appear at the same value. In addition, the general pattern... 

The knotted topology of the first synthetic trefoil was first demonstrated by mass and NMR spectroscopy, but was later fully confirmed by an X-ray structure determination showing this situation [48] (Fig. 13). 

A theorem proved by O. Gonzalez and J. Maddocks (Global curvature, thickness, and the ideal shapes of knots. Proceedings ofthe National Academy of Sciences, USA, 96 [1999], 4769) in the context of knot topologies shows the remarkable connection between the three-point recipe and the tube thickness. 

Meyer, M. Albrecht-Gary, A.-M. Dietrich-Buchecker. C.O. Sauvage. J.-P. Dicopper(I) trefoil knots Topological and structural effects on the demetalation rates and mechanism. J. Am. Cheni. Soc. 1997, 119 (20). 4599-4607. and references cited therein. 

Fig. 5 Seeman .s synthesis of DNA knots. (From Du. S.M. Stollar, B.D. Seeman, N.C. A synthetic DNA molecule in three knotted topologies. J. Am. Chem. Soc. 1995. 117. 1194-1200.)...

First molecule with trefoil knot topology. Glass. 

An algebraic classification of some even-dimensional knots Topology 15, 363 - 373 (1976)... 

This bis-copper complex 252+.(BF4 )2 is a dark red crystalline solid (needles). The high resolution mass spectrum (FAB) of 252+.(BF4 )2 shows a molecular peak at 1816,74 (calculated molecular weight for 25 + = 1817.10). The NMR spectrum of 25 + is in complete agreement with its structure. Since 25 + contains a double helix on two copper(I) atoms, it is chiral. This was demonstrated in the presence of Pirkle s reagent.[33] In order to prove the knotted topology of 25 +, we had to consider the various possible compounds obtained in the cyclisation reaction. From a tetrafunctional double helicoidal precursor, several 2+2 connections are possible, with the most probable ones being indicated in Figure 11. 

The fixation of the knot topology means freezing of all spins 6, i.e. quenching of some disorder pattern of these spins on the lattice. 

---