Orthogonal actuation of a supramolecular double-porphyrin tweezer.
A supramolecular three-component double-porphyrin tweezer (PT) is prepared quantitatively using heteroleptic complex formation along the HETTAP methodology. Insertion of guest molecules, such as DABCO or pyrazine, into the coupled porphyrin cavities of PT leads to an actuation of the double-porphyrin tweezer function. Evidence from (1)H NMR, VT NMR, and UV-vis titration suggests a rapid association/dissociation of the DABCO molecules at the central porphyrin. Upon addition of an equimolar mixture of DABCO and pyrazine to PT, a dynamic five-component self-assembled structure was furnished exclusively. (1)H NMR and K(assoc) values validate the greater stability of the heteroloaded PT-(DABCO)(py) system in comparison to the two homoloaded systems, PT-(DABCO)(2) and PT-(py)(2). The higher stability of PT-(DABCO)(py) seems to be the result of charge transfer from DABCO to the vacant pi* orbital of pyrazine across the porphyrin plane.
Schmittel
Michael
M
Center for Micro- and Nanochemistry and Engineering, Organische Chemie I, Adolf-Reichwein Str., Universität Siegen, D-57068 Siegen, Germany. schmittel@chemie.uni-siegen.de
Samanta
Soumen K
SK
D018360:Crystallography, X-Ray; D046911:Macromolecular Substances / Q000138:chemical synthesis / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D010879:Piperazines / Q000737:chemistry; D011166:Porphyrins / Q000138:chemical synthesis* / Q000737:chemistry*; D011719:Pyrazines / Q000737:chemistry; D015032:Zinc / Q000737:chemistry
D046911:Macromolecular Substances; D009942:Organometallic Compounds; D010879:Piperazines; D011166:Porphyrins; D011719:Pyrazines; D015032:Zinc; C007306:triethylenediamine