Daoyu Liu

Influence of the molecular configuration on second-order nonlinear optical properties of coordination compounds

Abstract The relationships between structure and nonlinear optical (NLO) properties of coordination compounds in terms of influence of molecular configuration on linear and NLO properties are reviewed. The molecular configurations involved are square pyramidal, tetrahedral, square planar, octahedral, sandwich and linear. Based on the experimental results, empirical rules of these relationships have been proposed, which may help the design of new NLO materials from organometallic and coordination compounds.

A tetrahedral coordination compound for second-order nonlinear optics: synthesis, crystal structure and SHG of Zn(2-NH2py)2Cl2

A coordination compound with a tetrahedral molecular configuration, Zn(NH 2 py) 2 Cl 2 (2-NH 2 py=2-aminopyridine), was prepared. It is transparent in the visible region and shows second harmonic generation (SHG) effect 8.0 times as strong as that of KDP. X-ray single crystal structure analysis reveals that all Zn(NH 2 py) 2 Cl 2 molecules are aligned in a fully parallel direction. The advantages and disadvantages of tetrahedral zinc coordination compounds as nonlinear optical (NLO) materials are discussed. The results may represent a novel strategy for designing a new class of transparent NLO materials.

Synthesis, photoconduction and electro-optical effect of a polysilane with disperse red-1 as side chain*

Abstract The structure of polymethylphenylsilane (PMPS) was modified by chloromethylation and then condensation with sodium salt of Disperse Red-1 (DR-1). The product (PMPS-DR1) shows a broad absorption in the wavelength of 400–700nm, and exhibits glass transition at ca. 155°C. Photoconductivity of a 2μm thick film made of PMPS-DR1 was measured to be in the range of 10 −18 ~10 −11 Scm −1 , and electric field dependent. After electrical poling, the film shows electro-optical effect with r 33 = O. 8pm/V.

Synthesis and X-ray structure of a semiconducting organometallic salt [FeCp(Tol)]2[Ni(mnt)2]☆

Abstract The compound [FeCp(Tol)] 2 [Ni(mnt) 2 ] has been prepared from [FeCp(Tol)]AlCl 4 and Na 2 [Ni(mnt) 2 ]. This new organometallic radical ionic salt has been characterized by elemental analysis, IR, 1 H NMR and mass spectroscopy. The X-ray structure of the compound shows there are segregated cation and anion stacks in the perpendicular directions. The molecular anions form a zig-zag stacking along the b axis, and between every two neighbouring anion planes a methyl group of the cation is inserted. This gives rise to a long spacing of 6.87 A between the anion planes. The cations stack along the c axis, with the closest spacing of 3.457 A between the cyclopentadienyl plane and the neighbouring toluene plane, which is shorter than the sum of Van der Wall′s radii. Conductivity measurements showed the compound as a semiconductor with a room temperature conductivity of 1.6 × 10 −4 Scm −1 .

Synthesis and Ferromagnetism of a New Intercalation Compound: Mn0.86PS3(bipy)0.56

Abstract Reaction of 2,2-bipyridine with layered MnPS 3 gives a new intercalation compound with a formula, Mn 0.86 PS 3 (bipy) 0.56 . X-ray powder diffraction experiment indicates that a complete intercalation and well crystallized product has been achieved. Ferromagnetism of the intercalate has been confirmed by SQUID experiment with T c at 40 K.

Determination of the first molecular hyperpolarizability, β, of some organomercury compounds by solvatochromism

Abstract Twelve arylmercuric nitrophenylacetylides, (where DI, Br, Cl, MeO, EtO, Me, H2N, MeHN, Me2N or O2N; R1H or Me; R2H or Me), have been synthesised, and their β, the first molecular hyperpolarizability, have been examined by solvatochromism to be in the order of 10−29 esu while the λmax in the electronic spectra are around 310nm. These linear organomercury molecules may represent a new approach to solve the conflict between increasing nonlinearity and improving transparency.

Square pyramidal coordination compound for SHG: Zn(acac)2(PhTU)

The title compound has been synthesized by reaction of ZnCl2, acetylacetone (acacH) and phenylthiourea (PhTU), and characterized by a variety of techniques. This compound is completely transparent in the visible region, and shows a powder SHG (second harmonic generation) effect as strong as 10 times that of KDP. X-ray single crystal structure analysis reveals that the molecule possesses a square pyramidal configuration around zinc ion. The molecules are aligned almost parallely in the lattice so that the geometrical superposition of the molecular dipole moment and the first hyperpolarizability ((beta) ) are favorably enhanced, giving rise to a relatively strong macroscopic SHG effect.

The role of two coordination compounds as novel transparent nonlinear optical crystals

Abstract This paper reports the synthesis, structure and properties of two coordination compounds which are transparent in the visible region and show a relatively strong nonlinear optical (NLO) effect. The first crystal, Zn(2-NH 2 py) 2 CI 2 (2-aminopyridine zinc dichloride, DAZC), shows a SHG (second harmonic generation) effect 8 times as strong as that of KDP. X-ray single crystal structure analysis reveals that the molecule possesses a tetrahedron configuration around the zinc atom, and all the molecules are aligned in an almost fully parallel direction.The second compound, Zn(acac) 2 (PhTU) (phenylthiourea zinc diacetylacetate, PZDA), shows a powder SHG effect as strong as 10 times that of KDP. X-ray single crystal structure analysis shows that the molecule possesses a square pyramidal configuration around the zinc ion, and the molecules are aligned almost in a parallel arrangement in the lattice. These two crystals may represent a novel strategy for designing new transparent NLO materials.

Synthesis and SHG effect of some cyclotriphosphazene derivatives

Twenty derivatives of hexachlorocyclotriphosphazene were synthesized by substituted reaction. The structure of the cyclotriphosphazenes were identified by i.r. uv-vis, n.m.r. and elemental analysis, proving that they are fully substituted cyclotriphosphazenes. Kurtz powder determination of SHG showed that two of them displayed SHG effect. X-ray diffraction determination of N3P3(OC6H4F)6 is presented to explain SHG effect.

NONLINEAR OPTICAL PROPERTY OF SOME ORGANO-TITANIUM AND -ZIRCONIUM COMPOUNDS

This paper describes the design, synthesis, characterization and powder second harmonic generation (SHG) effect of some organo-titanium and -zirconium compounds of the type of Cp 2 M(Cl)-EAr (Cp = cyclopentadienyl, M = Ti or Zr, E = O, S).