1,727,053 research outputs found
Synthesis and luminescence behavior of rhenium(I) triynyl complexes. X-ray crystal structures of [Re(CO)3(tBu2bpy)(C=C-C=C-C=CPh)]and [Re(CO)3(Me2bpy)(C=C-C=C-C=CSiMe3)]
No full textLuminescent rhenium(I) triynyl complexes [Re(CO)3(tBu2bpy)(C-C-C=C-C=CPh)] 1, [Re(CO)3(tBu2bpy)(C=C-C=C-C=CSiMe3)] 2, and [Re(CO)3(Me2bpy)(C=C-C=C-C= CSiMe3)] 3, were synthesized and their photophysical and electrochemical properties studied. The X-ray crystal structures of 1 and 3 have also been determined. A comparison study of their emission properties to that of their mono- and diynyl analogues was made and their emission origin suggested and supported by EHMO studies. © 2000 American Chemical Society.link_to_subscribed_fulltex
Heptahexaenylidene Complexes: Synthesis and Characterization of the First Complexes with an MCCCCCCCR<sub>2</sub> Moiety (M = Cr, W)
No full textSilica-induced elimination of dimethylamide from [(CO)5M(C⋮C)3C(NMe2)3]- [M = Cr (4a), W (4b)]
affords the first isolated and characterized heptahexaenylidene complexes [(CO)5MCCCCCCC(NMe2)2] (5a,b). Complexes 4a,b were generated by sequential reaction of Me3Si(C⋮C)3SiMe3
with LiMe·LiBr, [(Me2N)3C]+Cl-, LiBu, and [(CO)5M(thf)]. Complex 5b is inert in methanol, but adds
dimethylamine across the C5C6 bond to give [(CO)5WCCCCC{CHC(NMe2)2}NMe2]. The
reaction of 5a,b with LiMe·LiBr and SiO2 generates the heptahexaenylidene complexes [(CO)5MCCCCCCC(Me)NMe2] (8a,b). Trapping of 8b with HNMe2 yields pentatetraenylidene complex
[(CO)5WCCCCC{CHC(Me)NMe2}NMe2]
Microwave Spectra of Four New Perfluoromethyl Polyyne Chains: Trifluoropentadiyne, CF<sub>3</sub>C⋮CC⋮CH, Trifluoroheptatriyne, CF<sub>3</sub>C⋮CC⋮CC⋮CH, Tetrafluoropentadiyne, CF<sub>3</sub>C⋮CC⋮CF, and Trifluoromethylcyanoacetylene, CF<sub>3</sub>C⋮CC⋮N
No full textFour fluoromethyl polyynes, 5,5,5-trifluoro-1,3-pentadiyne, CF3C⋮CC⋮CH, 7,7,7-trifluoro-1,3,5-heptatriyne, CF3C⋮CC⋮CC⋮CH, 1,5,5,5-tetrafluoro-1,3-pentadiyne, CF3C⋮CC⋮CF, and 4,4,4-trifluoro-1-nitrile-2-butyne, CF3C⋮CC⋮N, were studied by pulsed-jet Fabry Perot Fourier transform
microwave spectroscopy. The molecules were produced by pulsed high voltage discharges of dilute mixtures
of precursor gases such as trifluoropropyne in an argon carrier pulsed jet. The carbon-13 and deuterium
substituted isotopomers of trifluoropentadiyne were studied, and the molecular structure was determined
Cationic and Neutral [4]-Cumulenes CCCCC with Five Cumulated Carbons and Three to Four Ferrocenyl Termini
No full textStarting from 1,1-diferrocenyl-1-methoxypropyne, the first
air-stable C5-cumulenium salt
(Fc)2CCCCC(Fc)+BF4-
(Fc = ferrocenyl) can be synthesized by a metalation,
iodination,
cross-coupling, and dehydration sequence. Attempted nucleophilic
attack of ferrocenyl
carbanion affords only radical decomposition products and none of the
desired tetraferrocenyl-C5-cumulene
(Fc)2CCCCC(Fc)2. In
contrast, reaction with phenyllithium yields the
nucleophilic addition product (Fc)2CCC(R)C⋮CFc
(R = C6H5) with 100%
regioselectivity.
Starting from diferrocenyl ketone, the first air-stable protonated
C5-cumulenium salt
(Fc)2CCHCCC(Fc)2+BF4-
is prepared by stepwise substitution of propyne with
diferrocenyl(methoxy)methyl groups and subsequent 2-fold
dehydration. Addition of methoxide
affords
(Fc)2CCC(R)CΗC(Fc)2 (R =
OCH3); attempted conversion to tetraferrocenyl-C5-cumulene
(Fc)2CCCCC(Fc)2 by thermal
elimination of methanol in vacuo fails but
yields an unusual cyclobutene dimer with eight ferrocenyl substituents.
Finally, deprotonation of
(Fc)2CCHCCC(Fc)2+BF4-
with “super base” n-BuLi/t-BuOK gives access
to
tetraferrocenyl-C5-cumulene
(Fc)2CCCCC(Fc)2, one of the
very few C5-cumulenes
known. IR, Raman, UV−vis, MS, NMR, Mössbauer spectroscopy,
cyclic voltammetry, and
X-ray crystallography are used for a detailed characterization of these
metallocenylcumulene
compounds
Cationic and Neutral [4]-Cumulenes CCCCC with Five Cumulated Carbons and Three to Four Ferrocenyl Termini
No full textStarting from 1,1-diferrocenyl-1-methoxypropyne, the first
air-stable C5-cumulenium salt
(Fc)2CCCCC(Fc)+BF4-
(Fc = ferrocenyl) can be synthesized by a metalation,
iodination,
cross-coupling, and dehydration sequence. Attempted nucleophilic
attack of ferrocenyl
carbanion affords only radical decomposition products and none of the
desired tetraferrocenyl-C5-cumulene
(Fc)2CCCCC(Fc)2. In
contrast, reaction with phenyllithium yields the
nucleophilic addition product (Fc)2CCC(R)C⋮CFc
(R = C6H5) with 100%
regioselectivity.
Starting from diferrocenyl ketone, the first air-stable protonated
C5-cumulenium salt
(Fc)2CCHCCC(Fc)2+BF4-
is prepared by stepwise substitution of propyne with
diferrocenyl(methoxy)methyl groups and subsequent 2-fold
dehydration. Addition of methoxide
affords
(Fc)2CCC(R)CΗC(Fc)2 (R =
OCH3); attempted conversion to tetraferrocenyl-C5-cumulene
(Fc)2CCCCC(Fc)2 by thermal
elimination of methanol in vacuo fails but
yields an unusual cyclobutene dimer with eight ferrocenyl substituents.
Finally, deprotonation of
(Fc)2CCHCCC(Fc)2+BF4-
with “super base” n-BuLi/t-BuOK gives access
to
tetraferrocenyl-C5-cumulene
(Fc)2CCCCC(Fc)2, one of the
very few C5-cumulenes
known. IR, Raman, UV−vis, MS, NMR, Mössbauer spectroscopy,
cyclic voltammetry, and
X-ray crystallography are used for a detailed characterization of these
metallocenylcumulene
compounds
On the Way to Heptahexaenylidene Complexes: Trapping of an Intermediate with the Novel MCCCCCCCR<sub>2</sub> Moiety
No full textSequential treatment of the in situ generated
heptatriyne
Me3SiC⋮CC⋮CC⋮CC(NMe2)3
with n-BuLi,
(CO)5W[THF], and
BF3·OEt2 affords the first
alkenyl-substituted pentatetraenylidene complex,
(CO)5WC
CCCC(NMe2)C(H)C(NMe2)2
(4), via addition of
dimethylamine to the CεCζ bond of the
intermediate
heptahexaenylidene complex
(CO)5WCαCβCγCδ
CεCζCη(NMe2)2.
In addition, the alkynyl(butatrienyl)carbene complex
(CO)5WC(C⋮CSiMe3)C(Bu)C
CC(NMe2)2 (5) is formed
Preparation of Phosphorescent Iridium(III) Complexes with a Dianionic C,C,C,C-Tetradentate Ligand
Get PDFThe
preparation and photophysical properties of heteroleptic iridium(III)
complexes containing a dianionic C,C,C,C-tetradentate ligand and a
cyclometalated phenylpyridine group are described. Complex [Ir(μ-OMe)(COD)]2 (1, COD = 1,5-cyclooctadiene) reacts with 1,1-diphenyl-3,3-butylenediimidazolium
iodide ([PhIm(CH2)4ImPh]I2), in the presence NaOtBu, to give [Ir(μ-I){κ4-C,C,C,C-[C6H4Im(CH2)4ImC6H4]}]2 (2), which leads to {[Ir{κ4-C,C,C,C-[C6H4Im(CH2)4ImC6H4]}]2(μ-OH)(μ-OMe)} (3) by treatment first with silver trifluoromethanesulfonate (AgOTf)
in acetone–dichloromethane and subsequently with KOH in methanol.
The reaction of 2 with AgOTf and acetonitrile affords
the bis(solvento) complex [Ir{κ4-C,C,C,C-[C6H4Im(CH2)4ImC6H4]}(CH3CN)2]OTf (4). The latter promotes the pyridyl-supported heterolytic ortho-CH bond activation of the phenyl group of 2-phenylpyridine,
2-(2,4-difluorophenyl)pyridine, 2-(p-tolyl)pyridine,
and 5-methyl-2-phenylpyridine to yield Ir{κ4-C,C,C,C-[C6H4Im(CH2)4ImC6H4]}{κ2-C,N-[Ar-py]} (Ar-py = C6H4-py
(5), C6H2F2-py (6), C6H3Me-py (7), C6H4-Mepy (8)) using (piperidinomethyl)polystyrene
as an external base. Complexes 5–8 are blue-green emitters, which display short lifetimes (0.6–4.8
μs) and quantum yields close to unity in both doped poly(methyl
methacrylate) films at 5 wt % and in 2-methyltetrahydrofuran at room
temperature
Synthesis and Luminescence Behavior of Rhenium(I) Triynyl Complexes. X-ray Crystal Structures of [Re(CO)<sub>3</sub>(<sup>t</sup>Bu<sub>2</sub>bpy)(C⋮C−C⋮C−C⋮CPh)] and [Re(CO)<sub>3</sub>(Me<sub>2</sub>bpy)(C⋮C−C⋮C−C⋮CSiMe<sub>3</sub>)]
No full textLuminescent rhenium(I) triynyl complexes [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CPh)] 1,
[Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CSiMe3)] 2, and [Re(CO)3(Me2bpy)(C⋮C−C⋮CC⋮CSiMe3)] 3, were synthesized and their photophysical and electrochemical properties studied.
The X-ray crystal structures of 1 and 3 have also been determined. A comparison study of
their emission properties to that of their mono- and diynyl analogues was made and their
emission origin suggested and supported by EHMO studies
Synthesis and Luminescence Behavior of Rhenium(I) Triynyl Complexes. X-ray Crystal Structures of [Re(CO)<sub>3</sub>(<sup>t</sup>Bu<sub>2</sub>bpy)(C⋮C−C⋮C−C⋮CPh)] and [Re(CO)<sub>3</sub>(Me<sub>2</sub>bpy)(C⋮C−C⋮C−C⋮CSiMe<sub>3</sub>)]
No full textLuminescent rhenium(I) triynyl complexes [Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CPh)] 1,
[Re(CO)3(tBu2bpy)(C⋮C−C⋮C−C⋮CSiMe3)] 2, and [Re(CO)3(Me2bpy)(C⋮C−C⋮CC⋮CSiMe3)] 3, were synthesized and their photophysical and electrochemical properties studied.
The X-ray crystal structures of 1 and 3 have also been determined. A comparison study of
their emission properties to that of their mono- and diynyl analogues was made and their
emission origin suggested and supported by EHMO studies
The rotational spectre of cyanoacetylene dimer, H-C-C-C-N ••• H-C-C-C-N
Get PDF\begin{wrapfigure}{r}{0pt}
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The rotational spectra of H-C-C-C-N ••• H-C-C-C-N, cyanoacetylene dimer,were recorded using Balle-Flygare type Fourier transform microwave (FTMW) spectrometers at Wesleyan and Arizona. The low-J transitions were measured down to 1.3 GHz at very high resolution, FWHM ~1 kHz using a large-cavity spectrometer. The spectral hyperfine structure due to the N nuclear quadrupole coupling interactions is well-resolved below 4 GHz using a low frequency spectrometer at the University of Arizona. The experimental spectroscopic constants were fitted as: B = 339.292331(8) MHz, D = 32.15(8) Hz, H = -0.0015(2) Hz, eqQ(N) = -3.990(1) MHz, and eqQ(N) = -4.171(1) MHz. The vibrationally averaged dimer configuration is \\ H-C-C-C-N ••• H-C-C-C-N. Using a simple linear model, the vibrational ground state and the equilibrium hydrogen bond lengths are determined to be: r(N ••• H) = 2.2489(3) \AA and r(N ••• H) = 2.2315 \AA. The equilibrium center-of-mass distance between the two HCCCN subunits is = 7.0366 \AA. Using the rigid precession model, the vibrational ground state center-of-mass distance and the pivot angles which HCCCN subunits make with the a-axis of H-C-C-C-N ••• H-C-C-C-N are = 7.0603 \AA, = , and = , respectively. The calculated hydrogen bond energy of H-C-C-C-N ••• H-C-C-C-N is 1466 cm using the MP2/aug-cc-PVTZ method in present work.Made available in DSpace on 2017-01-26T21:39:30Z (GMT). No. of bitstreams: 3
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Previous issue date: 2016-06-2
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