1-Cyano-1 '-ethynyl-ferrocene: Synthesis and reaction chemistry

Frank Strehler, Marcus Korb, Elisabeth A. Poppitz, Heinrich Lang

Research output: Contribution to journalArticle

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Abstract

Several consecutive synthetic methodologies for the preparation of Fe(eta(5)-C5H4C N)(eta(5)-C5H4C CH) (3) are described. Ferrocene Fe(eta(5)-C5H4C N)(eta(5)-C5H4C(O)Me) (1) reacts under typical Vilsmeier conditions to give as the main product Fe(eta(5)-C5H4C N)(eta(5)-C5H4CCl=CH2) (2) and in minor yield Fe(eta(C5H4C)-C-5 N)(eta(5)-C5H4CCl=CHC(O)H) (4). Compound 2 could be directly converted to 3 by addition of (KOBu)-Bu-t. The title compound is also accessible by the gradual reaction of 4 with NaOH to give Fe(eta(C5H4C)-C-5(O)NH2)(eta(5)-C5H4C CH) (5), which upon treatment with 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) and P(O)Cl(OEt)(2) produced 3. Organometallic 3 could be homo-coupled to [Fe(eta(5)-C5H4C N)(eta(C5H4C)-C-5 C)](2) (7) in an Eglinton coupling upon addition of [Cu(OAc)(2)]. With [CuI] and NEt2H in dichloromethane, compound Fe(eta(5)-C5H4C N)(eta(5)-C5H4C CCH2NEt2) (6) was produced by copper-catalyzed three-component coupling. The structures of 3-5 in the solid state were determined by single crystal X-ray structure analysis. While the X-ray structures of 3 and 4 show no peculiarities, the structure of 5 possesses a network structure due to hydrogen bridge bond formation. The electrochemical behavior of 3, 6 and 7 was studied by cyclic voltammetry. It could be shown that 3 possesses a reversible redox event at 550 mV (Delta E = 65 mV), while in homo-coupled 7 two consecutive redox processes at 524 and 680 mV were found indicating that the ferrocenyl units in 7 can be oxidized in a stepwise manner to 7(+) and 7(2+), respectively. The redox separation Delta E with 156 mV implies a possible electron transfer in the mixed-valent species 7(+), which was confirmed by spectroelectrochemical studies. From these studies, 7 could be classified as a weakly coupled class II system according to Robin and Day. (C) 2015 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)1-9
Number of pages9
JournalJournal of Organometallic Chemistry
Volume786
DOIs
Publication statusPublished - 15 Jun 2015
Externally publishedYes

Cite this

Strehler, Frank ; Korb, Marcus ; Poppitz, Elisabeth A. ; Lang, Heinrich. / 1-Cyano-1 '-ethynyl-ferrocene : Synthesis and reaction chemistry. In: Journal of Organometallic Chemistry. 2015 ; Vol. 786. pp. 1-9.
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abstract = "Several consecutive synthetic methodologies for the preparation of Fe(eta(5)-C5H4C N)(eta(5)-C5H4C CH) (3) are described. Ferrocene Fe(eta(5)-C5H4C N)(eta(5)-C5H4C(O)Me) (1) reacts under typical Vilsmeier conditions to give as the main product Fe(eta(5)-C5H4C N)(eta(5)-C5H4CCl=CH2) (2) and in minor yield Fe(eta(C5H4C)-C-5 N)(eta(5)-C5H4CCl=CHC(O)H) (4). Compound 2 could be directly converted to 3 by addition of (KOBu)-Bu-t. The title compound is also accessible by the gradual reaction of 4 with NaOH to give Fe(eta(C5H4C)-C-5(O)NH2)(eta(5)-C5H4C CH) (5), which upon treatment with 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) and P(O)Cl(OEt)(2) produced 3. Organometallic 3 could be homo-coupled to [Fe(eta(5)-C5H4C N)(eta(C5H4C)-C-5 C)](2) (7) in an Eglinton coupling upon addition of [Cu(OAc)(2)]. With [CuI] and NEt2H in dichloromethane, compound Fe(eta(5)-C5H4C N)(eta(5)-C5H4C CCH2NEt2) (6) was produced by copper-catalyzed three-component coupling. The structures of 3-5 in the solid state were determined by single crystal X-ray structure analysis. While the X-ray structures of 3 and 4 show no peculiarities, the structure of 5 possesses a network structure due to hydrogen bridge bond formation. The electrochemical behavior of 3, 6 and 7 was studied by cyclic voltammetry. It could be shown that 3 possesses a reversible redox event at 550 mV (Delta E = 65 mV), while in homo-coupled 7 two consecutive redox processes at 524 and 680 mV were found indicating that the ferrocenyl units in 7 can be oxidized in a stepwise manner to 7(+) and 7(2+), respectively. The redox separation Delta E with 156 mV implies a possible electron transfer in the mixed-valent species 7(+), which was confirmed by spectroelectrochemical studies. From these studies, 7 could be classified as a weakly coupled class II system according to Robin and Day. (C) 2015 Elsevier B.V. All rights reserved.",
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1-Cyano-1 '-ethynyl-ferrocene : Synthesis and reaction chemistry. / Strehler, Frank; Korb, Marcus; Poppitz, Elisabeth A.; Lang, Heinrich.

In: Journal of Organometallic Chemistry, Vol. 786, 15.06.2015, p. 1-9.

Research output: Contribution to journalArticle

TY - JOUR

T1 - 1-Cyano-1 '-ethynyl-ferrocene

T2 - Synthesis and reaction chemistry

AU - Strehler, Frank

AU - Korb, Marcus

AU - Poppitz, Elisabeth A.

AU - Lang, Heinrich

PY - 2015/6/15

Y1 - 2015/6/15

N2 - Several consecutive synthetic methodologies for the preparation of Fe(eta(5)-C5H4C N)(eta(5)-C5H4C CH) (3) are described. Ferrocene Fe(eta(5)-C5H4C N)(eta(5)-C5H4C(O)Me) (1) reacts under typical Vilsmeier conditions to give as the main product Fe(eta(5)-C5H4C N)(eta(5)-C5H4CCl=CH2) (2) and in minor yield Fe(eta(C5H4C)-C-5 N)(eta(5)-C5H4CCl=CHC(O)H) (4). Compound 2 could be directly converted to 3 by addition of (KOBu)-Bu-t. The title compound is also accessible by the gradual reaction of 4 with NaOH to give Fe(eta(C5H4C)-C-5(O)NH2)(eta(5)-C5H4C CH) (5), which upon treatment with 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) and P(O)Cl(OEt)(2) produced 3. Organometallic 3 could be homo-coupled to [Fe(eta(5)-C5H4C N)(eta(C5H4C)-C-5 C)](2) (7) in an Eglinton coupling upon addition of [Cu(OAc)(2)]. With [CuI] and NEt2H in dichloromethane, compound Fe(eta(5)-C5H4C N)(eta(5)-C5H4C CCH2NEt2) (6) was produced by copper-catalyzed three-component coupling. The structures of 3-5 in the solid state were determined by single crystal X-ray structure analysis. While the X-ray structures of 3 and 4 show no peculiarities, the structure of 5 possesses a network structure due to hydrogen bridge bond formation. The electrochemical behavior of 3, 6 and 7 was studied by cyclic voltammetry. It could be shown that 3 possesses a reversible redox event at 550 mV (Delta E = 65 mV), while in homo-coupled 7 two consecutive redox processes at 524 and 680 mV were found indicating that the ferrocenyl units in 7 can be oxidized in a stepwise manner to 7(+) and 7(2+), respectively. The redox separation Delta E with 156 mV implies a possible electron transfer in the mixed-valent species 7(+), which was confirmed by spectroelectrochemical studies. From these studies, 7 could be classified as a weakly coupled class II system according to Robin and Day. (C) 2015 Elsevier B.V. All rights reserved.

AB - Several consecutive synthetic methodologies for the preparation of Fe(eta(5)-C5H4C N)(eta(5)-C5H4C CH) (3) are described. Ferrocene Fe(eta(5)-C5H4C N)(eta(5)-C5H4C(O)Me) (1) reacts under typical Vilsmeier conditions to give as the main product Fe(eta(5)-C5H4C N)(eta(5)-C5H4CCl=CH2) (2) and in minor yield Fe(eta(C5H4C)-C-5 N)(eta(5)-C5H4CCl=CHC(O)H) (4). Compound 2 could be directly converted to 3 by addition of (KOBu)-Bu-t. The title compound is also accessible by the gradual reaction of 4 with NaOH to give Fe(eta(C5H4C)-C-5(O)NH2)(eta(5)-C5H4C CH) (5), which upon treatment with 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) and P(O)Cl(OEt)(2) produced 3. Organometallic 3 could be homo-coupled to [Fe(eta(5)-C5H4C N)(eta(C5H4C)-C-5 C)](2) (7) in an Eglinton coupling upon addition of [Cu(OAc)(2)]. With [CuI] and NEt2H in dichloromethane, compound Fe(eta(5)-C5H4C N)(eta(5)-C5H4C CCH2NEt2) (6) was produced by copper-catalyzed three-component coupling. The structures of 3-5 in the solid state were determined by single crystal X-ray structure analysis. While the X-ray structures of 3 and 4 show no peculiarities, the structure of 5 possesses a network structure due to hydrogen bridge bond formation. The electrochemical behavior of 3, 6 and 7 was studied by cyclic voltammetry. It could be shown that 3 possesses a reversible redox event at 550 mV (Delta E = 65 mV), while in homo-coupled 7 two consecutive redox processes at 524 and 680 mV were found indicating that the ferrocenyl units in 7 can be oxidized in a stepwise manner to 7(+) and 7(2+), respectively. The redox separation Delta E with 156 mV implies a possible electron transfer in the mixed-valent species 7(+), which was confirmed by spectroelectrochemical studies. From these studies, 7 could be classified as a weakly coupled class II system according to Robin and Day. (C) 2015 Elsevier B.V. All rights reserved.

KW - Ferrocene

KW - Alkyne

KW - Nitrile

KW - Electrochemistry

KW - Solid state structure

KW - INTRAMOLECULAR ELECTRONIC COMMUNICATION

KW - ORGANOMETALLIC CHELATING LIGANDS

KW - UNSATURATED HYDROCARBON BRIDGES

KW - NONLINEAR-OPTICAL PROPERTIES

KW - TRANSITION-METAL-COMPLEXES

KW - MIXED-VALENCE IONS

KW - ELECTROCHEMICAL OXIDATION

KW - COORDINATED NITRILES

KW - 5-MEMBERED HETEROCYCLES

KW - ACETYLIDE COMPLEXES

U2 - 10.1016/j.jorganchem.2015.02.049

DO - 10.1016/j.jorganchem.2015.02.049

M3 - Article

VL - 786

SP - 1

EP - 9

JO - Journal of Organometallic Chemistry

JF - Journal of Organometallic Chemistry

SN - 0022-328X

ER -