Self-assembled Transition Metal Coordination Frameworks of ...

Introduction
According to some studies [26,27] regarding the physical basis of self­
assembly macrocyclization for the l:l model system, the formation of macrocyclic
species can only be accomplished in a certain concentration range between the lower
self-assembly concentration (lsac) and the effective molarity (EM) of the self­
assembled macrocycle; since monomer and linear oligomers prefer to exist in the
lower and higher concentration ranges, respectively. In a qualitative manner, this
distribution of various self-assembled species as a filnction of concentration is
illustrated [13] in Fig. 1.2. The parameter EM is a measure for the concentration at
which open polymeric structures start to compete with the respective macrocycles
(here the squares), while lsac refers to the concentration at which the macrocycle is
half-assembled from the initial building blocks.
M . M o q-‘Q,-4§_ 8 J-F’ 1 \ -—, _ i -_, -Q­
MonOm&\F\\ / 'lu5€1:r*f>’C‘>"cl8 I met
iisac ' EM
Concentration
Fig. 1.2. The distribution of self-assembly species as a function of concentration.
According to this thermodynamic analysis of self-assembly macrocyclization,
desired macrocyclic products exist as major species only within a limited range of
concentration under given temperature and solvent conditions [13]. In order to
accomplish self-assembly already at low concentration, the coordinative bonds should
ll