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Introduction
Trianglimines with different cavity sizes (i.e., 10-12) can be prepared by simple choice of the
target dialdehyde component. 9,10 Changing the distance between the two carbonyl moieties varies
the size of the central hole of trianglimines. An efficient strategy for the synthesis of dialdehydes
with different sizes is the Suzuki coupling of formylboronic acids with different bromophenyls.
Macrocycle 10 is an example of a small size trianglimine obtained in reaction of 2,5-diformylfuran
with (1R,2R)-1,2-diaminocyclohexane 1. Unlike the case with trianglimine 4, macrocycle
10 assumes a s-syn conformation due to repulsion between the sp 2 -lone pairs at oxygen and
nitrogen atoms. Macrocycles 11 and 12, which constitute medium and large size trianglimines,
can be obtained by reacting 4,4'-biphenyldicarboxaldehyde and bis-(4-formylbenzene)-4,4'-
biphenyl with 1 (Figure 2.4).
Figure 2.4 Trianglimines 10-12 with different cavity sizes.
2.2. Applications of trianglimines
The [3+3]-cyclocondensation reaction (i.e., for trianglimine macrocycles) has attracted
considerable attention in supramolecular chemistry. 11,12 Trianglimines have been synthesized a
decade ago, however only few examples describing their applications are reported in literature.
The recognition ability of trianglimines has been initially described by Gawroński and coworkers.
1 The authors reported the X-ray structure for a 1:1 inclusion complex of trianglimine/
ethylacetate. The ability of trianglimines or trianglamines to host small size neutral organic
guests and metal ions was reported in many occasions. 13-16 Varying the cavity dimensions of
trianglimine has led to the synthesis of more sophisticated structures of trianglimine, which
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