Metal-side chain interaction in tricarbonylchromium complexes of phenylacetylenes studied by 13C NMR and IR spectroscopy

Szewczyk, Jerzy; Gryff‐Keller, Adam

doi:10.1016/0022-328x(92)85005-h

Cited by 8 publications

(2 citation statements)

References 20 publications

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“…The reactions with TCNE and Pd catalysts were carried out under an inert atmosphere by applying a positive pressure of Ar. Compounds 2, [7] 10, [7] 11, [7] 22, [30] 23, [31] 26, [32] 31, [33] 32, [32] 35, [34] 36, [35] 37, [36] 38, [37] and 4-ethynyl-N,N-dihexylaniline [38] were prepared according to literature procedures. Column chromatography (CC) and plug filtrations were carried out with Fluka SiO 2 60 (particle size 40-63 mm, 230-400 mesh) or Fluka Al 2 O 3 (particle size 50-150 mm) and distilled technical solvents.…”

Section: Methodsmentioning

confidence: 99%

Donor‐Substituted 1,1,4,4‐Tetracyanobutadienes (TCBDs): New Chromophores with Efficient Intramolecular Charge‐Transfer Interactions by Atom‐Economic Synthesis

Michinobu

Boudon²,

Gisselbrecht³

et al. 2006

Chemistry A European J

268

231

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A wide variety of monomeric and oligomeric, donor-substituted 1,1,4,4-tetracyanobutadienes (TCBDs) have been synthesized by [2+2] cycloaddition between tetracyanoethylene (TNCE) and donor-substituted alkynes, followed by electrocyclic ring opening of the initially formed cyclobutenes. Reaction yields are often nearly quantitative but can be affected by the electron-donating power and steric demands of the alkyne substituents. The intramolecular charge-transfer (CT) interactions between the donor and TCBD acceptor moieties were comprehensively investigated by X-ray crystallography, electrochemistry, UV-visible spectroscopy, and theoretical calculations. Despite the nonplanarity of the new chromophores, which have a substantial twist between the two dicyanovinyl planes, efficient intramolecular CT interactions are observed, and the crystal structures demonstrate a high quinoid character in strong donor substituents, such as N,N-dimethylanilino (DMA) rings. The maxima of the CT bands shift bathochromically upon reduction of the amount of conjugative coupling between strong donor and acceptor moieties. Each TCBD moiety undergoes two reversible, one-electron reduction steps. Thus, a tri-TCBD derivative with a 1,3,5-trisubstituted benzene core shows six reversible reduction steps within an exceptionally narrow potential range of 1.0 V. The first reduction potential E(red,1) is strongly influenced by the donor substitution: introduction of more donor moieties causes an increasingly twisted TCBD structure, a fact that results in the elevation of the LUMO level and, consequently, a more difficult first reduction. The potentials are also strongly influenced by the nature of the donor residues and the extent of donor-acceptor coupling. A careful comparison of electrochemical data and the correlation with UV-visible spectra made it possible to estimate unknown physical parameters such as the E(red,1) of unsubstituted TCBD (-0.31 V vs Fc+/Fc) as well as the maxima of highly broadened CT bands. Donor-substituted TCBDs are stable molecules and can be sublimed without decomposition. With their high third-order optical nonlinearities, as revealed in preliminary measurements, they should become interesting chromophores for ultra-thin film formation by vapor deposition techniques and have applications in opto-electronic devices.

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Section: Methodsmentioning

confidence: 99%

Donor‐Substituted 1,1,4,4‐Tetracyanobutadienes (TCBDs): New Chromophores with Efficient Intramolecular Charge‐Transfer Interactions by Atom‐Economic Synthesis

Michinobu

Boudon²,

Gisselbrecht³

et al. 2006

Chemistry A European J

268

231

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“…The above mild reaction conditions also imply that the reactivity of the complexed vinyl chlorides 1 toward Pd(0) insertion is similar to that of an ordinary aryl iodide or bromide 13c as the Sonogashira coupling of (η 6 -chlorobenzene)Cr(CO) 3 with phenylacetylene was conducted under similar experimental conditions but at refluxing temperature of THF 14c…”

Section: Resultsmentioning

confidence: 92%

Activation of the Vinylic C−Cl Bond by Complexation of Fe(CO)₃: Palladium-Catalyzed Coupling Reactions of (η⁴-Chlorodiene)tricarbonyliron Complexes

Qian

2006

Organometallics

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The reactions of 1-chloro-or 2-chloro-substituted (η 4 -1,3-cyclohexadiene)Fe(CO) 3 complexes with terminal alkynes under the catalysis of PdCl 2 (PPh 3 ) 2 /CuI at 45-60 °C led to the formation of the corresponding Sonogashira coupling products in 64-97% yields. The complexes also underwent smoothly the intermolecular Heck reactions with activated alkenes under the catalysis of Pd(OAc) 2 /PPh 3 at 60 °C to afford the expected coupling products in 39-83% yields. On the other hand, the corresponding uncomplexed molecule 2-chloro-1,3-cyclohexadiene remained inert under the same reaction conditions. These results clearly demonstrated the strong activation effect of Fe(CO) 3 on the oxidative cleavage of the vinylic C-Cl bond.

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Palladium‐Copper‐Catalyzed Coupling of Tricarbonylchromium‐Complexed Phenylacetylene with Iodoarenes – A Facile Access to Alkynyl‐Bridged Cr(CO)₃‐Complexed Benzenes

Müller

Lindner

1996

Chem. Ber.

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The palladium-copper-catalyzed coupling of the tricarbonylchromium-complexed chlorobenzene 1 with (trimethylsily1)-acetylene gives tricarbonyl($-[(trimethylsilyl)ethynyl]-benzene}chromium(O) (2) in high yield. After desilylation of 2 tricarbonyl[q6-(ethynylbenzene)]chromium(O) (3) is obtained quantitatively. Using the palladium-copper-catalyzed methodology, we can readily introduce Cr(C0)3-complexed phenylethynyl units by a multifold coupling of 3 with iodobenzene, 1,2-, 1,3-, 1,4-di-and 1,3,5-tiiodobenzene (4a-e) or 1 to give polynuclear Cr(CO)3-complexed (phenylethyny1)benzenes 5a-e and doubly Cr(CO),-complexed tolane 6 in good to moderate yield. Acetylenes have experienced a true renaissance as rigid bridging elements in x-conjugated polymers['], dendrimerst2], and synthetic carbon allotropes[3] on the way to the architecture of nanostructures. In particular, alkynes have been of interest not only as bridges but also as transmitters of z-electron resonance in novel electro-and chromophoresL4]. n-Conjugated systems fundamentally change their electronical behavior and reactivity on complexation with organometallic fragmentst51. Thus, the prospect of fine-tuning optical and electronical properties by attaching organometallic units to a conjugated chain or macrocycle[61 has had an important impact on the rapidly evolving search for syntheses and structures of novel organometallic conjugated target molecules. So far some oligo-and polymeric cyclobutadienylalkynyl complexes of cobalt and iron ['] have successfully been synthesized.However, there is not much known about the synthesis and the chemistry of tricarbonylchromium-complexed alkynylarene~[~,~], interesting building blocks in the synthesis of Cr(CO)3-complexed poly(phenylenealkyny1enes) and oligo(arylenea1kynyl)macrocycles. This has several reasons. The pyrolysis of hexacarbonylchromium in the presence of alkynylarenes is an unselective and ineficient force brute synthe~is~~~'] that does not tolerate alkynes Cr(C0)3-transferring complexes like (CH3CN)3Cr(C0)3[81 or (NH3)3Cr(C0)3[1"l can be used under milder conditions but the regioselectivity of complexation cannot be controlled. Therefore, coupling reactions offer chemo-and regioselective alternatives. The Stille coupling of alkynylstannanes and Cr(C0)3-complexed chlorobenzenes proved to be a very efficient option and was successfully applied to the synthesis of Cr(CO)3-complexed polylphenylenealkynylenes)" l]. However, the inherent toxicity of tin compounds and the rather uneconomical application of alkynylstannanes require a catalytic mode of metalation and transmetalation of terminal alkynes. Here we report on an efficient synthesis of Cr(C0)3-complexed phenylacetylene and a regioselective route to novel (arene)tricarbonylchromium(O) complexes. Results and DiscussionThe palladium-copper-catalyzed coupling of terminal acetylenes [12] with iodo-or bromoarenes is a well established methodology for the synthesis of alkynylarenes. Cr(CO)3-complexed chlorobenzene was used in a coupling reaction with terminal ...

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Metal-side chain interaction in tricarbonylchromium complexes of phenylacetylenes studied by 13C NMR and IR spectroscopy

Cited by 8 publications

References 20 publications

Donor‐Substituted 1,1,4,4‐Tetracyanobutadienes (TCBDs): New Chromophores with Efficient Intramolecular Charge‐Transfer Interactions by Atom‐Economic Synthesis

Donor‐Substituted 1,1,4,4‐Tetracyanobutadienes (TCBDs): New Chromophores with Efficient Intramolecular Charge‐Transfer Interactions by Atom‐Economic Synthesis

Activation of the Vinylic C−Cl Bond by Complexation of Fe(CO)₃: Palladium-Catalyzed Coupling Reactions of (η⁴-Chlorodiene)tricarbonyliron Complexes

Palladium‐Copper‐Catalyzed Coupling of Tricarbonylchromium‐Complexed Phenylacetylene with Iodoarenes – A Facile Access to Alkynyl‐Bridged Cr(CO)₃‐Complexed Benzenes

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Metal-side chain interaction in tricarbonylchromium complexes of phenylacetylenes studied by 13C NMR and IR spectroscopy

Cited by 8 publications

References 20 publications

Donor‐Substituted 1,1,4,4‐Tetracyanobutadienes (TCBDs): New Chromophores with Efficient Intramolecular Charge‐Transfer Interactions by Atom‐Economic Synthesis

Donor‐Substituted 1,1,4,4‐Tetracyanobutadienes (TCBDs): New Chromophores with Efficient Intramolecular Charge‐Transfer Interactions by Atom‐Economic Synthesis

Activation of the Vinylic C−Cl Bond by Complexation of Fe(CO)3: Palladium-Catalyzed Coupling Reactions of (η4-Chlorodiene)tricarbonyliron Complexes

Palladium‐Copper‐Catalyzed Coupling of Tricarbonylchromium‐Complexed Phenylacetylene with Iodoarenes – A Facile Access to Alkynyl‐Bridged Cr(CO)3‐Complexed Benzenes

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Activation of the Vinylic C−Cl Bond by Complexation of Fe(CO)₃: Palladium-Catalyzed Coupling Reactions of (η⁴-Chlorodiene)tricarbonyliron Complexes

Palladium‐Copper‐Catalyzed Coupling of Tricarbonylchromium‐Complexed Phenylacetylene with Iodoarenes – A Facile Access to Alkynyl‐Bridged Cr(CO)₃‐Complexed Benzenes