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Nonlinear optical properties of luminescent multinuclear platinum(II) complex of branched alkynyls in benzene solution are investigated at room temperature by using two-photon fluorescence (TPF) technique. It is found that the material shows unusual nonlinear optical characteristics under the excitation of near infrared femtosecond laser pulses. The self-focusing of laser beam energy during propagation of the laser pulses in the sample with large nonlinear coefficient for the refractive index is observed. Based on this phenomenon, a new method for measuring the nonlinear coefficient and two-photon absorption cross section of materials is proposed. [ABSTRACT FROM AUTHOR]

Dinuclear alkynylplatinum(II) terpyridyl complexes with oligomeric bridge consisting of five repeating meta-phenylene ethynylene (mPE) units have been found to exhibit a strong tendency to fold back onto themselves to form short helical strands through the stabilization of Pt···Pt and π-π interactions. The steric bulk of the terpyridine ligands and the length of the oligomeric bridge have been found to affect the extent of the intramolecular Pt···Pt interaction that governs the stabilization of the short helical strand in solution. Their folding properties via Pt···Pt and π-π stacking interactions have been studied by (1)H NMR, 2D ROESY NMR, electronic absorption, and emission spectroscopies., (© 2011 American Chemical Society)

The synthesis of newly designed photochromic dithienylethene-containing ethynylthiophene and ethynylthieno[3,2-b]thiophene has been described, and their incorporation as versatile ligands into the platinum(II) phosphine system was demonstrated. All platinum(II) complexes have been successfully characterized by (1)H and (31)P NMR spectroscopies, positive fast atom bombardment (FAB) mass spectrometry, as well as elemental analysis. One of the complexes has been characterized by X-ray crystallography. Their photophysical, photochromic, and electrochemical properties have been studied. Upon photoexcitation, all the photochromic diarylethene-containing alkynes and platinum(II) complexes exhibited reversible photochromism. The thermal bleaching kinetic of complex 6 was studied in toluene at 298 and 313 K. Complexes 1, 3, and 4, which contained the labile chloro- ligand, represent a new class of versatile building blocks for photoswitchable functional materials.

A series of luminescent platinum(II) alkynyl complexes containing 2,5-diphenyl-1,3,4-oxadiazole (oxa-2,5) and 10,15-dihydro-5H-diindeno[1,2-a;1',2'-c]fluorene (truxene) as the cores and different electron donors at the periphery has been synthesized and characterized. These complexes showed long-lived emissions in both solution and in the solid state at room temperature and have been found to exhibit two-photon absorption (2PA) and two-photon induced luminescence. Their 2PA cross-sections (sigma(2)) have also been determined.