Spin clusters, organic

The practical implementation of organic spin clusters was through the synthesis of polyradicals, in which relatively weak and relatively strong fCUs were based upon 3,4 -biphenylene and 1,3-phenylene connectivities. Based upon the spin densities in conformationally unconstrained systems, factor of 6 was predicted for the relative strength of exchange coupling in 3,4 -biphenylene and 1,3-phenylene.3,107,108... 

Fig. 27 Design of high-spin organic spin cluster.

Macrocyclic-macrocyclic polyradicals consist of macrocyclic branches connected to macrocyclic cores via bis(3,4 -biphenylene)methyl linkers (Figs 32 and 33). The connection of calix[4]arene-based macrocycles via bis(3,4 -biphenylene)methyl linkers provided special type of organic spin clusters, in which large component spins of the macrocycles were exchange coupled via much smaller spins 1/2 of the linkers, as illustrated in Figs 32 and 33 for polyradicals 51-53.8 112... 

Fig. 32 Macrocyclic-macrocyclic organic spin clusters of unequal spins 51 and 52.112...

Fig. 33 Macrocyclic-macrocyclic organic spin cluster of unequal spin 53.112...

Rajca, S., Rajca, A., Wongsriratanakul, J., Butler, P. and Choi, S. (2004). Organic spin clusters. Dendritic-macrocyclic poly ary lmethyl polyradical with very high-spin of 5=10 and its derivatives synthesis, magnetic studies, and small angle neutron scattering. J. Am. Chem. Soc. 126, 6972-6986... 

Rajca, A. (1997). High-spin organic polyradicals as simple spin clusters. Mol. Cryst. Liq. Cryst. 305, 567-577... 

Rajca, S. and Rajca, A. (2001). Polyarylmethyl polyradicals as organic spin clusters. J. Solid State Chem. 159, 460-465... 

Rajca, A. (2002). Organic spin clusters, fractals, and networks with very high-spin. In Hyper-structured Molecules III, Sasabe, H. (ed.), Chapter 3, pp. 46-60, Taylor Francis, London... 

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