Anthracene-TCNB

See in this connection the examples given in Chaps. 1 and 2, anthracene-TCNB (Fig. 1.6) and in Chap. 6, anthracene-PMDA (Fig. 6.14). 

Weak donor-acceptor complexes, nonpolar in the ground state Anthracene-Tetracyanobenzene (TCNB) 1.6... 

Fig. 1.6 The crystal structure ofthe weak donor-acceptor crystal anthracene-tetracyanobenzene (TCNB). One can clearly see how the two components alternate in parallel planes. The CN groups are indicated by a darker shade. The crystal structure is monoclinic, with a = 9.528 A, b= 12.779 A, c= 7.441 A, i8 = 92.39°.

In this chapter, we will not discuss the weak CT complexes further. In these complexes, at least in the ground state, the charge transfer S is not large. They in general crystallise in mixed, alternating stacks. We have already mentioned the example systems anthracene-tetracyanobenzene or A-TCNB (cf Fig. 1.6) and anthracene-pyromellitic acid-dianydride or A-PMDA (cf Fig. 6.14). 

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