title: Two photon absorption properties of four coordinated transition metal complexes of tetraarylazadipyrromethene compounds.
abstract: New tetraarylazadipyrromethene metal complexes with four coordinate metals (cobalt(ii), nickel(ii), copper(ii) and zinc(ii)) and with three moieties (4-methylphenyl,4-methoxyphenyl and 1-naphthyl) were designed and synthesized targeting applications utilizing two photon absorption. The effects of metals with filled or unfilled d orbitals and substituents with various electron donor properties on the charge transfer mechanism and two photon absorption properties of tetraarylazadipyrromethene compounds were investigated by ultrafast pump-probe spectroscopy and open aperture Z-scan experiments as well as density functional theory (DFT) calculations. Ultrafast transient absorption spectra provide evidence of an efficient photoinduced intramolecular charge transfer between the ligand and metals which is independent of filled or unfilled d orbitals of metals. Although zinc has filled d orbitals, its complexes possess an absorption maximum including a shoulder which is attributed to partial ligand to metal L(π) → M(d*) charge transfer character (LMCT). Due to the charge transfer mechanism, metal complexes of tetraarylazadipyrromethene compounds exhibited two photon absorption properties in the femtosecond regime at 800 nm wavelength. The greatest two photon absorption cross section value was measured as 2690 GM for Zn(L(2))2 and 2374 GM for Co(L(3))2 complexes.
authors.affiliation: Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Beşevler, Ankara, Turkey. yoglu@eng.ankara.edu.tr.
authors.forename: E
authors.initials: E
authors.lastname: Akhüseyin
authors.affiliation: Department of Chemistry, Faculty of Science, Ankara University, 06100 Beşevler, Ankara, Turkey. Mustafa.Hayvali@science.ankara.edu.tr hayvali@science.ankara.edu.tr.
authors.forename: O
authors.initials: O
authors.lastname: Türkmen
authors.affiliation: Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Beşevler, Ankara, Turkey. yoglu@eng.ankara.edu.tr.
authors.forename: B
authors.initials: B
authors.lastname: Küçüköz
authors.affiliation: Department of Chemistry, Faculty of Science, Ankara University, 06100 Beşevler, Ankara, Turkey. Mustafa.Hayvali@science.ankara.edu.tr hayvali@science.ankara.edu.tr.
authors.forename: H
authors.initials: H
authors.lastname: Yılmaz
authors.affiliation: Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Beşevler, Ankara, Turkey. yoglu@eng.ankara.edu.tr.
authors.forename: A
authors.initials: A
authors.lastname: Karatay
authors.affiliation: Department of Chemistry, Faculty of Science, Ankara University, 06100 Beşevler, Ankara, Turkey. Mustafa.Hayvali@science.ankara.edu.tr hayvali@science.ankara.edu.tr.
authors.forename: G
authors.initials: G
authors.lastname: Sevinç
authors.affiliation: State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling Gong Road, Dalian 116024, China.
authors.forename: K
authors.initials: K
authors.lastname: Xu
authors.affiliation: Department of Chemistry, Faculty of Science, Ankara University, 06100 Beşevler, Ankara, Turkey. Mustafa.Hayvali@science.ankara.edu.tr hayvali@science.ankara.edu.tr.
authors.forename: M
authors.initials: M
authors.lastname: Hayvali
authors.affiliation: Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Beşevler, Ankara, Turkey. yoglu@eng.ankara.edu.tr.
authors.forename: H G
authors.initials: HG
authors.lastname: Yaglioglu