From supramolecular porphyrin tweezers to dynamic A(n)B(m)C(l)D(k) multiporphyrin arrangements through orthogonal coordination.
A dynamic, supramolecular, three-component A(n)B(m)C(l) bis(zinc porphyrin) tweezer has been prepared quantitatively using the heteroleptic bisphenanthroline (HETPHEN) concept. Upon addition of nitrogenous spacers of different length, namely, the extended bipyridine 3 a, 4,4'-bipyridine (3 b), and 1,4-diazabicyclo[2.2.2]octane (DABCO; 3 c), to set up an additional orthogonal binding motif (Zn(Por)-N(spacer)), three structurally different, still dynamic, four-component A(n)B(m)C(l)D(k) assemblies were cleanly formed, as indicated by UV/Vis and NMR titrations as well as by DOSY investigations. The structures were identified as a bridged monotweezer A(2)BC(2)D, a doubly bridged double tweezer A(4)B(2)C(4)D(2), and a triply bridged double tweezer A(4)B(2)C(4)D(3), the latter resembling a porphyrin stack. Notably, the same structures were equally formed directly from a mixture of the constituents A, B, C, and D put together in any sequence if the correct stoichiometry was applied.
Kishore
Ravuri S K
RS
Center of Micro- and Nanochemistry and Engineering, Organische Chemie, Universität Siegen, Adolf-Reichwein-Strasse, 57068 Siegen, Germany.
Paululat
Thomas
T
Schmittel
Michael
M
D010879:Piperazines / Q000138:chemical synthesis*; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry*; D011725:Pyridines / Q000138:chemical synthesis*
D010879:Piperazines; D011166:Porphyrins; D011725:Pyridines; C007306:triethylenediamine