Tropocoronand ligand

[7] Asymmetrical tropocoronands where the number of carbons of the simple straight-chain linkages is different (m ≠ n, but variability in the m,n lengths tends to be only by 1 methylene group)[8][9] as well as chiral tropocoronands[10] can be synthesized using the method outlined in Scheme 1 with the modification of the last step where the straight-chain diamine can be substituted to the diamine with a different length of chain (m ≠ n) or to the chiral one.

An alternative synthesis involves placing the chiral group in the sequence first to form a diaminoketone, followed by cyclization with a straight chain diamine in the last step.

have been studied in order to determine how the differences in macrocycle ring size, metal ionic radius, and electronic structure can affect the dihedral angle of the tropocoronand ligand.

However, the dihedral angles of the cadmium tropocoronand complexes are smaller despite the larger metal ion radius.

Studies of divalent Co2+ and Ni2+ complexes showed that the electronic structure of the transition metal ion affects the dihedral angle: the TC-4,5 ligand adopts a larger dihedral angle for the Co2+ ion, likely resulting due to its greater preference for tetrahedral over square-planar geometry as well as differences in ligand field stabilization energies (LFSE).