Synthesis, Structure and Electrochemistry of Macrocyclic Tetrametallic Group 6 (Fischer) Carbene Complexes

López‐Alberca, María P.; Mancheño, María J.; Fernández, Israel; Gallego, Manuel Requena; Sierra, Miguel Á.; Hemmert, Catherine; Gornitzka, Heinz

doi:10.1002/ejic.201001007

Cited by 17 publications

(8 citation statements)

References 77 publications

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“…This is in part due to the formation of an intramolecular hydrogen bond between the NH of the aniline moiety and the ethoxy-substituent attached to the carbene carbon atom which greatly stabilizes the Z -configuration. This intramolecular N–H···OR hydrogen bond has also been found to be responsible for the high stability of the Z -configuration in related enaminocarbenes, , including those found in macrocycles tetrametallic complexes . In addition, this intramolecular interaction also stabilizes the anti conformation exhibited by the ethoxy-substituent (i.e., the CH 2 group directly attached to the oxygen atom is oriented toward the CO wall of the metal fragment), which is the preferred conformation for most of the alkoxy Fischer carbene complexes both in gas phase and in solid state .…”

Section: Results and Discussionmentioning

confidence: 92%

Remote Control by π-Conjugation of the Emissive Properties of Fischer Carbene-BODIPY Dyads

et al. 2016

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The synthesis, structure, and complete characterization of mono- and bimetallic dyads joining Fischer carbene complexes and BODIPY chromophores are reported. In these organometallic species, the Fischer carbene complex is attached to the BODIPY moiety through a p-aminophenyl group linked at the C8 carbon atom of the BODIPY core. The photophysical properties, namely the corresponding UV/vis absorption and emission spectra of these new metal-carbene complexes, are analyzed and discussed. It is found that whereas the absorption of the considered dyads strongly resembles that of the parent 4-anilinyl-substituted BODIPY, the fluorescence emission is significantly reduced in these species, very likely as a result of a Förster-type energy transfer mechanism. At variance, the replacement of the pentacarbonyl-metal(0) fragment by a carbonyl group leads to high fluorescence emission intensity. In addition, the emissive properties of the BODIPY core in these organometallic dyads can be tuned by remote groups by means of π-conjugation, as supported by density functional theory calculations.

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Section: Results and Discussionmentioning

confidence: 92%

Remote Control by π-Conjugation of the Emissive Properties of Fischer Carbene-BODIPY Dyads

et al. 2016

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“…Commercially available reagents were used without further purification. Azides 2 , 4 , and 6 , and alkynyl carbene complexes 1a , 1b , 1c , 1d , and 1e were prepared following literature procedures.…”

Section: Methodsmentioning

confidence: 99%

Effect of a κ¹-Bonded-M-1,2,3-triazole (M = Co, Ru) on the Structure and Reactivity of Group 6 Alkoxy (Fischer) Carbenes

et al. 2017

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The [3 + 2] cycloaddition of two different metal-bound azides, [(Mecyclam)Co(N)]ClO and (η-CH)(dppe)Ru(N), (dppe = PhPCHCHPPh) with Cr(0) and W(0) (ethoxy)(alkynyl) Fischer carbenes has been efficiently used for the preparation of polymetallic metal-carbene complexes. The presence of the κ-bonded metal triazole causes a significant influence on the electronic properties, structure, and reactivity of this new class of Fischer alkoxycarbenes. For the Ru(II) derivatives, their chemical behavior is considerably influenced by the interaction of the (η-CH)(dppe)Ru-triazole moiety with the empty p-carbene orbital that provokes a noticeable decrease in the electrophilicity of the M═C carbon (manifested by the shielding of the C NMR chemical shifts). In turn, in the Co(II) derivatives, the incorporation of the (Mecyclam)Co moiety diminishes the aromaticity of the triazole ring and has a marked effect on the energy and distribution of the LUSO orbital, mostly resident on the Co(II) fragment. The almost negligible participation of the carbene moiety in the LUSO makes this position unable to react with nucleophiles. The reactions reported in this work constitute the first examples of [3 + 2] cycloaddition of azides and alkynyl Fischer carbene complexes in solution.

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“…Commercially available reagents were used without further purification. Compounds 1a (M = Cr, R = Ph), 1b (M = Cr, R 1 = Fc), 1c (M = W, R = Ph), 1f (M = Cr, R = 4-methyl), 1g (M = Cr, R = 4-methoxy), 1h (M = Cr, R = 4-dimethylamino), 1j (M = W, R = 4-methyl), 2a , 2b , 2c , 3a , 4a , 4b , 8a , 8b , 8c , and 11 were prepared according to reported procedures. For experimental details of the synthesis and characterization of Fischer alkynyl carbene complexes 1d (M = Cr, R = 2-thienyl), 1e (M = Cr, R = 4-Br) and 1i (M = Cr, R = 4-CF 3 ) see the Supporting Information.…”

Section: Experimental Generalmentioning

confidence: 99%

Mono- and Bimetallic Zwitterionic Chromium(0) and Tungsten(0) Allenyls

et al. 2015

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A series of stable chiral (racemic), formally neutral, zwitterionic mono- and bimetallic M(CO)5[C(OEt)═C═CR(NHC)] (M = Cr, W) σ-allenyls are ready available by the addition of N-heterocyclic carbenes (NHCs) to Cr(0) and W(0) alkynyl Fischer carbene complexes. Different classes of NHCs, (e.g., 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene, 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene, and their six- and seven-membered analogues and 1,3-bis(dimethyl)imidazol-2-ylidene) were employed as nucleophiles in these C-C bond-forming reactions yielding the novel complexes in essentially quantitative yields. A systematic experimental and computational study of the electronic properties of the Cr- and W-allenyls shows that their UV-vis spectra are directly influenced by the structure of the heterocyclic moiety derived from the NHC (ring size, substituents on the N atoms) and by the nature of the metal fragment (Cr/W). The electron-releasing nature of these complexes allows them to participate in electron-transfer reactions in the ground state, leading to a type of charged α,β-unsaturated Fischer carbenes that incorporate an NHC fragment in their structure.

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Synthesis, Structure and Electrochemistry of Macrocyclic Tetrametallic Group 6 (Fischer) Carbene Complexes

Cited by 17 publications

References 77 publications

Remote Control by π-Conjugation of the Emissive Properties of Fischer Carbene-BODIPY Dyads

Remote Control by π-Conjugation of the Emissive Properties of Fischer Carbene-BODIPY Dyads

Effect of a κ¹-Bonded-M-1,2,3-triazole (M = Co, Ru) on the Structure and Reactivity of Group 6 Alkoxy (Fischer) Carbenes

Mono- and Bimetallic Zwitterionic Chromium(0) and Tungsten(0) Allenyls

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Synthesis, Structure and Electrochemistry of Macrocyclic Tetrametallic Group 6 (Fischer) Carbene Complexes

Cited by 17 publications

References 77 publications

Remote Control by π-Conjugation of the Emissive Properties of Fischer Carbene-BODIPY Dyads

Remote Control by π-Conjugation of the Emissive Properties of Fischer Carbene-BODIPY Dyads

Effect of a κ1-Bonded-M-1,2,3-triazole (M = Co, Ru) on the Structure and Reactivity of Group 6 Alkoxy (Fischer) Carbenes

Mono- and Bimetallic Zwitterionic Chromium(0) and Tungsten(0) Allenyls

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Effect of a κ¹-Bonded-M-1,2,3-triazole (M = Co, Ru) on the Structure and Reactivity of Group 6 Alkoxy (Fischer) Carbenes