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ABSTRACT: Planar platinum(II) complex Pt(Me(3)SiC≡CbpyC≡CSiMe(3))(C≡CC(6)H(4)CF(3)-4)(2) (6) with 5,5'-bis(trimethylsilylethynyl)-2,2'-bipyridine and 4-trifluoromethylphenylacetylide exhibits remarkable luminescence vapochromic and mechanochromic properties and a thermo-triggered luminescence change. Solid-state 6 is selectively sensitive to vapors of oxygen-containing volatile compounds such as tetrahydrofuran (THF), dioxane, and tetrahydropyrane (THP) with phosphorescence vapochromic response red shifts from 561 and 608 nm to 698 nm (THF), 689 nm (dioxane), and 715 nm (THP), respectively. Upon being mechanically ground, desolvated 6, 6·CH(2)Cl(2), and 6·(1)/(2)CH(2)ClCH(2)Cl exhibit significant mechanoluminescence red shifts from 561 and 608 nm to 730 nm, while vapochromic crystalline species 6·THF, 6·dioxane, or 6·THP affords a mechanoluminescence blue shift from 698 nm (THF), 689 nm (dioxane), or 715 nm (THP) to 645 nm, respectively. When the compounds are heated, a thermo-triggered luminescence change occurs, in which bright yellow luminescence at 561 and 608 nm turns to red luminescence at 667 nm with a drastic red shift. The multi-stimulus-responsive luminescence switches have been monitored by the changes in emission spectra and X-ray diffraction patterns. Both X-ray crystallographic and density functional theory studies suggest that the variation in the intermolecular Pt-Pt interaction is the key factor in inducing an intriguing luminescence switch.
Inorganic Chemistry 05/2012; 51(10):5569-79. · 4.60 Impact Factor
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ABSTRACT: Planar platinum(II) complexes Pt(bpyC≡CSiMe(3))(C≡CC(6)H(4)R-4)(2) (R = H (1), Bu(t) (2)) with 5-trimethylsilylethynyl-22'-bipyridine show an unusual, reversible, and reproducible mechanical stimuli-responsive color and luminescence switch. When crystalline 1 or 2 is ground, bright yellow-green emitting is immediately converted to red luminescence with an emission red shift of 121-155 nm for 1 or 53-89 nm for 2. Meanwhile, the crystalline state is transformed to an amorphous phase that can be reverted to the original crystalline state by organic vapor adsorbing or heating, along with red luminescence turning back to yellow-green emitting. The reversibility and reproducibility of luminescence mechanochromic properties have been dynamically monitored by the variations in emission spectra and X-ray diffraction patterns. The drastic grinding-triggered emission red shift is likely involved in the formation of a dimer or an aggregate through Pt-Pt interaction, resulting in a conversion of the (3)MLCT/(3)LLCT emissive state in the crystalline state into the (3)MMLCT triplet state in the amorphous phase. Compared with the drastic grinding-triggered emission red shift in 1 (121-155 nm), the corresponding response shift in 2 (53-89 nm) is much smaller since a bulky tert-butyl in C≡CC(6)H(4)bu(t)-4 induces the planar platinum(II) molecules to stack through a longer Pt-Pt distance and less intermetallic contact compared with that in 1, as suggested from EXAFS studies.
Inorganic Chemistry 08/2011; 50(18):9090-6. · 4.60 Impact Factor
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ABSTRACT: Square-planar bis(σ-fluorophenylacetylide) platinum(II) complexes [Pt(Me(3)SiC≡CbpyC≡C-SiMe(3))(C≡CC(6)H(4)F)(2)] (C≡CC(6)H(4)F-2 for 2, C≡CC(6)H(4)F-3 for 3, and C≡CC(6)H(4)F-4 for 4; Me(3)SiC≡CbpyC≡CSiMe(3)=5,5'-bis(trimethylsilylethynyl)-2,2'-bipyridine) were prepared and were characterized by spectroscopic and luminescence studies, and X-ray crystallography. The color and luminescence of crystalline complex 3 is specifically sensitive to CHCl(3) vapor to afford 140-180 nm of luminescence vapochromic redshift, which is useful for specific detection of CHCl(3) vapor. Complex 4 displays selective luminescence vapochromic properties to CH(2)Cl(2) and CHCl(3) vapors with a luminescence vapochromic shift response of ca. 150-200 nm. Interestingly, complexes 2-4 exhibit reversible, and naked-eye perceivable, mechanical stimuli-responsive color and luminescence changes. When solid species 2-4 are crushed gently or ground, the crystalline state is converted to an amorphous phase. Meanwhile, bright yellow-orange luminescence in the crystalline species is converted to dark red under UV light irradiation with 100-160 nm of mechanochromic shift response. A vapochromic or mechanochromic cycle was monitored by dynamic variations in emission spectra and X-ray diffraction (XRD) patterns. The halohydrocarbon vapor- or mechanical-grinding-triggered color and luminescence switches are most likely correlated to a shorted intermolecular Pt-Pt distance as that revealed in vapochromic species 4·0.5 CH(2)Cl(2) by X-ray crystallography, thus leading to an increased contribution from intermolecular Pt-Pt interaction as demonstrated by DTF computational studies.
Chemistry 01/2011; 17(4):1171-83. · 5.93 Impact Factor
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ABSTRACT: Platinum(II) complex [Pt(Me(3)SiC[triple bond]CbpyC[triple bond]CSiMe(3))(C[triple bond]CPh)(2)] (1) with 5,5-bis(trimethylsilylethynyl)-2,2'-bipyridine (Me(3)SiC[triple bond]CbpyC[triple bond]CSiMe(3)) and phenylacetylene (PhC[triple bond]CH) exhibits unusual luminescence vapochromism to volatile organic compounds (VOCs) including CH(2)Cl(2), CHCl(3), and CH(3)I, which is useful for detection of volatile halohydrocarbon with one carbon atom and molecular weight less of than 150. Crystal structural determination of 1, 1 x CHCl(3), 1 x 1/2(CH(2)ClCH(2)Cl), and 1 x 1/2(toluene) revealed a staggered packing for 1 x CHCl(3) whereas there was an antiparallel packing for other three structures in stacking of planar platinum(II) moieties. The Pt...Pt distance is 3.302(1) A in 1 x CHCl(3), whereas it is >4.0 A in the other three structures. Complex 1 displays bright orange luminescence in dichloromethane solution, arising from pi(phenylacetylide)-->pi*(Me(3)SiC[triple bond]CbpyC[triple bond]CSiMe(3)) (3)LLCT and d(Pt)-->pi*(Me(3)SiC[triple bond]CbpyC[triple bond]CSiMe(3)) (3)MLCT triplet states which are supported by DFT calculation. The solid-state emission occurs at approximately 762 nm for 1 x VOC (VOC = CH(2)Cl(2), CHCl(3), and CH(3)I), whereas it was at approximately 562 (603sh) or 603 (562sh) nm for 1 and other 1 x VOC, corresponding to a vapochromic response shift of approximately 160-200 nm. The dramatic vapochromism and vapoluminescence of 1 to the vapor of CH(2)Cl(2), CHCl(3), or CH(3)I are induced by a reversible conversion of the emissive state from (3)MLCT/(3)LLCT character to (3)MMLCT/(3)LLCT state.
Inorganic Chemistry 09/2009; 48(21):10202-10. · 4.60 Impact Factor
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ABSTRACT: A platinum(II) complex of 5,5'-bis(trimethylsilylethynyl)-2,2'-bipyridine displays unusually reversible colour and luminescence changes when exposed to specific organic vapours, correlated well with Pt...Pt distances as well as pi-pi and C-H...(C[triple bond]C) interactions in the stacking of square-planar platinum(II) moieties.
Chemical Communications 08/2009; · 6.17 Impact Factor
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Inorganic Chemistry 12/2008; · 4.60 Impact Factor
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ABSTRACT: Polypyridyl-functionalized alkynes are a class of bifunctional ligands and very useful for the design of heteropolynuclear or multicomponent arrays as optoelectronic materials at the molecular level. This article focuses on reviewing the recent progress in design of luminescent heteropolynuclear or multicomponent complexes composed of photoactive discrete subunits using 2,2'-bipyridyl, 1,10-phenanthroline or 2,2':6',2''-terpyridyl functionalized alkynyl ligands with both acetylide and polypyridyl groups. The preparation, molecular fabrication, structural features, and spectroscopic and luminescent properties are summarized to elucidate the correlation of structure and photophysical properties as well as triplet energy transfer between two or more photoactive organometallic subunits.
Dalton Transactions 03/2008; · 3.84 Impact Factor
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ABSTRACT: Reaction of cis-or trans-Pt(PPh 3) 2 Cl 2 (PPh 3) triphenylphosphine) with 5-[2-(trimethylsilyl)-1-ethynyl]-2,2′-bipyridine (bpyCtCSiMe 3) gave cis-Pt(PPh 3) 2 (CtCbpy) 2 (1) or trans-Pt(PPh 3) 2 (Ctbpy) 2 (5). Incorporating 1 or 5 with Ln(hfac) 3 (H 2 O) 2 (hfac) hexafluoroacetylacetonate) induced formation of the corresponding cis-or trans-PtLn 2 heterotrinuclear complexes cis-Pt(PPh 3) 2 {(CtCbpy)Ln(hfac) 3 } 2 (Ln) Nd 2, Eu 3, Yb 4) or geometrical isomers trans-Pt(PPh 3) 2 {(CtCbpy)Ln(hfac) 3 } 2 (Ln) Nd 6, Eu 7, Yb 8). As verified through 31 P NMR characterization as well as determination of the structures of 1, 4, and 8 by X-ray crystallography, the cis-or trans-arranged forms around Pt II centers remain unchanged in both solutions and solid states without thermal or light-induced isomerization during the reactions. With excitation at 360 < λ ex < 450 nm, which is the absorption region of metal-perturbed πfπ* (CtC) transitions and dπ(Pt)fπ*(CtCbpy) MLCT transition, sensitized lanthanide luminescence occurs with a microsecond range of lifetimes in both cis-and trans-arranged PtLn 2 complexes, revealing that efficient PtfLn energy transfer is indeed operating from the platinum(II) acetylide chromophore to lanthanide centers.
Organometallics 01/2008; 27:5665-5671. · 3.96 Impact Factor
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Journal of Organometallic Chemistry 694(3):339-345. · 2.38 Impact Factor
