title: Magnetic Control of the Charge-Separated State Lifetime Realized by Covalent Attachment of a Platinum Complex.
abstract: Dynamics of the photogenerated charge-separated (CS) state is studied for a newly synthesized molecular triad, in which the donor (D) dimethoxytriphenylamine, 1,3-bis(2-pyridylimino)isoindolate platinum (BPIPt), and the acceptor (A) naphthaldiimide are linked with a triethynylbenzene unit (BPIPt-DA). Photoexcitation of BPIPt gives rise to generation of a long-lived (∼4 μs) CS state BPIPt-D+A-, of which the lifetime is considerably increased by an applied magnetic field of 270 mT. The positive magnetic field effect (MFE) is in contrast to the negative MFE for the reference DA molecule, which indicates successful switching of the initial spin state of the CS state from singlet to triplet. Simulations of the MFE and time-resolved electron paramagnetic resonance show that spin-selective charge recombination and spin relaxation are unaffected by attachment of BPIPt. The minimum impact of heavy atom substitution on the electronic and magnetic properties has been realized by the small electronic coupling mediated by the rigid meta-triethynylbenzene.
authors.affiliation: Department of Chemistry, Faculty of Science, Niigata University , 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan.
authors.forename: Tomoaki
authors.identifier: http://orcid.org/0000-0002-7281-3049
authors.initials: T
authors.lastname: Miura
authors.affiliation: Department of Chemistry, Faculty of Science, Niigata University , 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan.
authors.forename: Dai
authors.initials: D
authors.lastname: Fujiwara
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University , Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Kimio
authors.initials: K
authors.lastname: Akiyama
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sugimoto Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Horikoshi
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sugimoto Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sugimoto Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Masatoshi
authors.identifier: http://orcid.org/0000-0002-9737-5639
authors.initials: M
authors.lastname: Kozaki
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka City University , Sugimoto Sumiyoshi-ku, Osaka 558-8585, Japan.
authors.forename: Keiji
authors.identifier: http://orcid.org/0000-0002-2817-9335
authors.initials: K
authors.lastname: Okada
authors.affiliation: Department of Chemistry, Faculty of Science, Niigata University , 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan.|Center for Instrumental Analysis, Niigata University , 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan.
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Ikoma