Article

Theoretical study of one- and two-photon absorption properties of octupolar D2d and D3 bipyridyl metal complexes.

State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, JiLin University, Changchun 130023, People's Republic of China.
The Journal of Physical Chemistry A (Impact Factor: 2.78). 03/2007; 111(7):1328-38. DOI: 10.1021/jp0669097
Source: PubMed

ABSTRACT The molecular equilibrium structures, electronic structures, and one- and two-photon absorption (TPA) properties of C2v (Zn(II), Fe(II) and Cu(I)) dipolar and D2d (Zn(II) and Cu(I)) and D3 (Zn(II)) octupolar metal complexes featuring different functionalized bipyridyl ligands have been studied by the ZINDO-SOS method. The calculated results show that one- and two-photon absorption properties of metal complexes are strongly influenced by the nature of the ligands (donor end groups and pi linkers) and metal ions as well as by the symmetry of the complexes. The length of the pi-conjugated backbone, the Lewis acidity of the metal ions, and the increase of ligand-to-metal ratio result in a substantial enhancement of the TPA cross sections of metal complexes. Substitution of C=N and N=N for C=C plays an important role in altering the maximum TPA wavelengths and the maximum TPA cross sections of metal complexes. Of them, the C=N substituted metal complexes have relatively large TPA cross sections. Replacing styryl with thienylvinyl makes the one-photon absorption wavelength red shift and at the same time leads to a great decrease of the maximum TPA cross sections of metal complexes. The possible reason is discussed. In the range 500-1250 nm, octupolar metal complexes exhibit intense TPAs and therefore are promising candidates for TPA materials.

0 Bookmarks
 · 
184 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Two new 4,4′-bis(donor)-6,6′-diphenyl- 2,2′-bipyridine ligands and their corresponding D2d (CuI, AgI, ZnII) octupolar metal complexes were synthesized, and their linear and nonlinear optical properties were investigated. A single crystal X-ray structure was also determined for the bis[4,4′-bis(diethylaminostyryl)-6,6′-diphenyl-bipyridine]copper(I) complex, which revealed a distorded pseudo-tetrahedral geometry. Molecular second-order nonlinear optical properties were determined for the complexes using the Harmonic Light Scatterring technique at 1.91 μm. These metallo-chromophores display large first hyperpolarizabilities β1.91 in the range of 211–340 × 10−30 esu, which increase with the Lewis acidity of the metal ion. The two-photon absorption properties of the bipyridyl ligands and related complexes were determined using either the two-photon emission method for fluorescent compounds or the open aperture Z-scan technique for non emissive ones. The complexes display red-shifted two-photon absorption bands compared to their metal-ion free chromophores, as well as a large increase of the maximum two-photon absorption cross-sections.
    Dyes and Pigments 01/2012; 92(1):681–688. · 3.47 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: New complexes with six ferrocenyl (Fc) groups connected to Zn(II) or Cd(II) tris(2,2'-bipyridyl) cores are described. A thorough characterisation of their BPh4 (-) salts includes two single-crystal X-ray structures, highly unusual for such species with multiple, extended substituents. Intense, visible d(Fe(II) )→π* metal-to-ligand charge-transfer (MLCT) bands accompany the π→π* intraligand charge-transfer absorptions in the near UV region. Each complex shows a single, fully reversible Fe(III/II) wave when probed electrochemically. Molecular quadratic nonlinear optical (NLO) responses are determined by using hyper-Rayleigh scattering and Stark spectroscopy. The latter gives static first hyperpolarisabilities β0 reaching as high as approximately 10(-27) esu and generally increasing with π-conjugation extension. Z-scan cubic NLO measurements reveal high two-photon absorption cross-sections σ2 of up to 5400 GM in one case. DFT calculations reproduce the π-conjugation dependence of β0 , and TD-DFT predicts three transitions close in energy contributing to the MLCT bands. The lowest energy transition has octupolar character, whereas the other two are degenerate and dipolar in nature.
    Chemistry - A European Journal 03/2013; · 5.93 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have theoretically investigated two series of cyclometalated Pt(II) complexes, a series [Pt (C, N, N) Cl] and b series [Pt (C, N, Npyrazolyl) Cl]. The geometrical and electronic structures are calculated at the ECP60MWB//6-31G*(H, C, Cl, N, S) basis set level using DFT method; one-photon absorption (OPA) properties are calculated by using both TDDFT and ZINDO methods and two-photon absorption (TPA) properties are obtained with the ZINDO/SOS method. The resonance integrals parameters (β sp and β d) for Pt are adjusted to −1 and −28.5 eV, respectively, to make max OPA wavelength calculated by ZINDO closest to the experimental data and TDDFT results. The calculated results indicate the molecule 2b ([Pt (Cnaphthyl, N, Npyrazolyl) Cl]) has the biggest potential as outstanding TPA materials because (i) the TPA properties of b series are more outstanding in IR wavelength range, the molecules in b series have good transparencies and possess 1-pyrazolyl-NH that is also available for another metal coordination (e.g., dimerization) and chemical interactions; (ii) when C is Cnaphthyl in the C, N, N ligand of cyclometalated Pt(II) complexes, the molecules have the best conjugation effect and the best TPA properties.
    Science China-Chemistry 55(7). · 1.52 Impact Factor