Physikalische Chemie - Direktor: Prof. Dr. Martin Wolf
Department Seminar
Host: T. Kumagai

Monday, February 13, 2017, 10:30 am
All are invited to meet around 10:10 am for a chat with coffee & cookies.
Willstätter House, Faradayweg 10
Dr. Ryota Sakamoto
Department of Chemistry, Graduate School of Science, University of Tokyo, Bunkyō-ku
New Aspects in Dipyrrin-Metal Complexes: From Molecular Science to Low-Dimensional Molecular Assemblies
The present paper is devoted to my achievements in dipyrrin-metal complex chemistry for this five years.[1] One of such examples includes heteroleptic (dissymmetric) bis(dipyrrinato)zinc(II) complexes that feature more intense luminescence than corresponding 4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes.[1a-f] We then expanded the concept of dissymmetry, creating dinuclear bis(dipyrrinato)zinc(II) complexes that transmit excitons quantitatively from one end to the other.[1g] Also, the concept of dissymmetry allowed us to fabricate [bis(oxazoline)](dipyrrinato)zinc(II) complexes that feature bright and circularly polarized luminescence from an originally achiral dipyrrinato ligand.[1h] Taking advantage of the spontaneous coordination reaction between dipyrrin and metal ions, we created two types of photofunctional molecular superstructures. A liquid/liquid interfacial reaction between a bridging dipyrrin ligand and metal(II) ions gives rise to single crystals of a one-dimensional coordination polymer suitable for X-ray diffraction analysis. Isolated single fibers of the zinc coordination polymer may be exfoliated from the single crystal or bulk solid upon ultrasonication. Atomic force microscopy detects the isolated fibers with lengths of more than several μm. The exfoliated wire features good processability, realizing a thin film on a transparent SnO2 electrode. The modified SnO2 electrode serves as a photoanode for a photoelectric conversion system.[1i,j] Although molecule-based bottom-up nanosheets manufactured directly from molecular components can exhibit greater structural diversity than top-down nanosheets, the bottom-up nanosheets reported thus far lack useful functionalities. Here we show the design and synthesis of a bottom-up nanosheet featuring a photoactive bis(dipyrrinato)zinc(II) complex motif. The bis(dipyrrinato)zinc(II) metal complex nanosheet is easy to deposit on various substrates using the Langmuir-Schafer process. The nanosheet deposited on a transparent SnO2electrode functions as a photoanode in a photoelectric conversion system and is thus the first photofunctional bottom-up nanosheet.[1k–m].
[1] (a) J. Am. Chem. Soc. 2016138, 5666. (b) Dalton Trans. 201544, 15103. (c) Inorg. Chem. 201453, 3275. (d) Molecules201318, 4090. (e) Dalton Trans. 201241, 14035. (f ) Chem. Asian J. 20127, 907. (g) Chem. Commun. 201450, 5881. (h) Angew. Chem. Int. Ed. 2016, 55, 1377. (i) Chem. Sci. 20156, 2853. (j) J. Mater. Chem. A 20153, 15357. (k) Nat. Commun. 20156, 6713. (l) Coord. Chem. Rev. 2016, doi:10.1016/j.ccr.2015.12.001. (m) Langmuir 201632, 2527. (n) Inorg. Chem. 2016, 10.1021/acs.inorgchem.6b00431. (o) Chem. Asian J. 20138, 723. (p) Electrochemistry201381, 337.