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Synthesis and nonlinear optical properties of eta(5)-monocyclopentadienyliron(II) acetylide derivatives. X-ray crystal structures of [Fe(eta(5)- C5H5)(DPPE)(p-C equivalent to CC6H4NO2)] and [Fe(eta(5)-C5H5)(DPPE)((E)-p-C equivalent to CC6H4C(H)=C(H)C6H4NO2)]
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| Abstract |
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| A series of new acetylide complexes of the type [Fe(eta(5)-C5H5)(Pboolean ANDP)(p-Cequivalent toCC(6)H(4)R)] (Pboolean ANDP = DPPE (=1,2-bis(diphenylphosphino)ethane), (R)-PROPHOS (=(R)-(+)-1,2-bis(diphenylphosphino)propane), R = NO2, C6H4NO2, (Z)-C(H) C(H)C6H4NO2, (E)-C(H)=C(H)C6H4NO2) have been synthesized by halide abstraction from the precursors [Fe(eta(5)-C5H5)(Pboolean ANDP)(1)] and fully characterized. Quadratic hyperpolarizabilities (beta) for the complexes have been determined by hyper-Rayleigh scattering at 1064 nm. The influence on the nonlinear response of acetylide chain length in proceeding from 4-nitrophenylethynyl to 4-nitrobiphenylethynyl and 4-nitro(E)-stibenylethynyl has been studied, revealing values of the first hyperpolarizabilities among the highest reported for organometallic molecular materials. Comparisons on the nonlinear efficiencies are drawn with the related well-known families of compounds [Ru(eta(5)-C5H5)(PR3)(2)(P-Cequivalent toC-(aryl)-NO2)] and [Fe(eta(5)-C6H5)(Pboolean ANDP)(P-Nequivalent toC-(aryl)-NO2)](+), Cubic hyperpolarizabilities (gamma) determined by Z-scan at 800 nm are consistent with an increase in) upon replacing Ru by the more easily oxidizable Fe and upon chain-lengthening the delocalizable pi-bridging unit (proceeding from 4-C6H4 to (E)-4,4'-C6H4CH=CHC6H4). X-ray C5H5)(DPPE)(P-Cequivalent toCC(6)H(4)NO(2))] and [Fe(eta(5)-crystallographic structures of complexes [Fe(eta(5)-C5H5)DPPE)((E)-p-Cequivalent toCC(6)H(4)C(H)=C(H)C6H4NO2)] were studied in order to investigate the existence of T-back-donation suggested by spectroscopic and electrochemical data. Crystal packing was analyzed with the aim of assessing the alignment of the molecules in the lattice and hence suggesting the magnitude of NLO properties at the macroscopic level. | | |
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English
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Organometallics / American Chemical Society. - Columbus, Ohio | |
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Columbus, Ohio : 2002
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0276-7333
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21:10(2002), p. 2107-2118
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000175632900016
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