A series of new ruthenium(II) complexes of the general formula [Ru(eta(5)-C5H5)(PP)(L)][PF6] (PP = DPPE or 2PPh(3), L = 4-butoxybenzonitrile or N-(3-cyanophenyl)formamide) and the binuclear iron(II) complex [Fe(eta(5)-C5H5)(PP)(mu-L)(PP)(eta(5)-C5H5)Fe][PF6](2) (L = (E)-2-(3-(4-nitrophenyl)allylidene)malononitrile, that has been also newly synthesized) have been prepared and studied to evaluate their potential in the second harmonic generation property. All the new compounds were fully characterized by NMR, IR and UV-Vis spectroscopies and their electrochemistry behaviour was studied by cyclic voltammetry. Quadratic hyperpolarizabilities (beta) of three of the complexes have been determined by hyper-Rayleigh scattering (HRS) measurements at fundamental wavelength of 1500 nm and the calculated static beta(0) values are found to fall in the range 65-212 x 10(-30) esu. Compound presenting beta(0) = 212 x 10(-30) esu has revealed to be 1.2 times more efficient than urea standard in the second harmonic generation (SHG) property, measured in the solid state by Kurtz powder technique, using a Nd:YAG laser (1064 nm). (C) 2013 Elsevier B.V. All rights reserved.

Various numerical methods exist for obtaining the radiances inside a canopy of leaves above a partly reflecting ground. In view of testing the accuracy of these diverse methods, it is desirable to have at one's disposal non-trivial models possessing analytical solutions, against which to compare numerical reuslts. Such models are obtained in the present paper, for the case of a horizontally homogeneous foliage of Lambertian leaves, modeled as a turbid medium. Our treatment is more general than usual in that we allow the top and under sides of leaves to have different optical coefficients. Besides being more realistic, this enables artificial situations, such as extreme light trapping, testing the limits of various numerical methods.

In many problems, it is necessary to integrate a transport equation. Here we consider specifically light incident on a horizontally homogeneous foliage ('the canopy'), modeled as a turbid medium. This is often treated by integrating numerically the light transport equation, assuming initial values for the reflected radiances, and iterating until the radiances stabilize. We here present a method combining transfer matrices, transmission-reflection matrices, and Green's matrices (TTRG). This method is both fast and accurate, especially if one must do many computations on the same canopy, for different incident fluxes and internal emissions. There exist (artificial) extreme light trapping situations for which iterative integration is hardly practical, while TTRG remains as efficient.

A method for numerically integrating transport equations, combining transfer matrices, transmission-reflection matrices, and Green's matrices (TTRG), was recently proposed. The present paper deals specifically with azymuthally integrated radiances inside a horizontally homogeneous canopy of Lambertian leaves. Its main purpose is to test the accuracy of TTRG by applying it to non-trivial models possessing analytical solutions, that were given in another paper. Comparison is made with the widely used iterative integration (or 'relaxation' method). Cases of extreme light trapping are given for which iterative integration is hardly practical, while TTRG remains as accurate and rapid.

In order to investigate the non-linear optical properties, in particular second-order effects of binuclear organometallic complexes, a series of new cationic binuclear [MCp-(DPPE)Nequivalent toC-(spacer)-Cequivalent toC-C6H5Cr(CO)(3)](+)[PF6](-) compounds and mononuclear precursors [Nequivalent toC-(spacer)-Cequivalent toC-C6H5Cr(CO)(3)] have been synthesised [where M = Fe-II or Ru-II; Cp = eta(5)-C5H5 and spacer = phenyl ring (C6H4), thiophene, (C4H2S), or bithiophene (C4H2S)(2)]. The Fe or Ru organometallic pi-donor fragments were linked by an extended pi system to the acceptor Cr(CO)(3) fragment. The effect of pi back-donation involving the second Fe or Ru metal centre and the pi(*) orbitals of the Nequivalent toC-coordinated group, was probed by the nu((Nequivalent toC)) stretching bands on the IR spectra and also by NMR spectroscopic data. The planarity, largely due to the pi-electron resonance, found on the solid state structure of the mononuclear complex [Nequivalent toC-C6H5-Cequivalent toC-(eta(6-)C(6)H(5))Cr(CO)(3)] (1Cr) determined by X-ray diffraction [monoclinic system, P2(1)/c space group, with a = 10.326(2) Angstrom, b = 13.209(5) Angstrom, c = 11.799(2) Angstrom and Z = 4] emphasises the electronic effect of this building block. The significant values of first hyperpolarisability beta determined by hyper-Rayleigh scattering (HRS) indicate that the Fe containing compounds were more efficient on second-order non-linear optical properties than the ruthenium analogues and the parent mononuclear chromium compounds. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).