Synthesis and Properties of Donor-Acceptor-Substituted Metal-Capped Fourfold-Bridged Cyclobutadienophanes

Gleiter, Rolf; Roers, Rolf; Classen, Jörg; Jacobi, Albrecht; Huttner, and Gottfried; Oeser, Thomas

doi:10.1021/om9907270

Cited by 12 publications

(9 citation statements)

References 10 publications

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“…This was anticipated since the donor character of one Cp ring increases in both series. [22] This finding suggests that the first electron is removed from the RCpCo fragment where R is either CH 3 , Si(CH 3 ) 3 or (CH 3 ) 5 . The assumption that the electrochemical oxidation removes the first electron from the donor-substituted unit allows us to probe the intramolecular interaction in the radical cation.…”

Section: Cyclovoltammetric Investigationsmentioning

confidence: 97%

Synthesis and Properties of Donor/Acceptor-Substituted Metal-Capped Twofold-Sila-Bridged Cyclobutadieno Superphanes

Schaller

Haberhauer

Gleiter

et al. 2002

Eur. J. Inorg. Chem.

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Keywords: Donor-acceptor systems / Phanes / Cyclic voltammetry / Electron transfer / CobaltThe synthesis of the tetrasilasuperphanes 10−18 can be achieved from 1,1,3,3-tetramethyl-1,3-disilacyclonona-4,8-diyne (7), 1,1,2,2-tetramethyl-1,2-disilacyclonona-3,8-diyne (8) or 1,1,4,4-tetramethyl-1,4-disilacyclodeca-5,9-diyne (9) by heating with [RCpCoL 2 ] [R = H, Si(CH 3 ) 3 , (CH 3 ) 5 , CO 2 CH 3 ; L 2 = COD, (CO) 2 , (C 2 H 4 ) 2 ]. The reaction of 7 with [RCpCo(CO) 2 ] [R = H, CH 3 , Si(CH 3 ) 3 , (CH 3 ) 5 ] produces the tricyclic cobalt-stabilized cyclobutadienediynes 20−23, whereas reaction with [RЈCpCo(L 2 )] [RЈ = H, (CH 3 ) 5 , CO 2 CH 3 ; L 2 = COD, (CO) 2 ] leads to the donor/acceptor superphanes 24−31. X-ray investigations on the superphanes

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Section: Cyclovoltammetric Investigationsmentioning

confidence: 97%

Synthesis and Properties of Donor/Acceptor-Substituted Metal-Capped Twofold-Sila-Bridged Cyclobutadieno Superphanes

Schaller

Haberhauer

Gleiter

et al. 2002

Eur. J. Inorg. Chem.

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“…(cofacial cyclobutadienyl-cobalt complexes), [71][72][73] Boekelheide, Jordan et al and Speiser et al [74,75] to significantly influence cobalt redox potentials. [76] The redox potentials of Grubbs II complexes with saturated and unsaturated NHC (but identical 4-R groups) are very similar (with the exception of 4-R = NEt 2 ); indicative of similar donor properties in the two classes of ligands.…”

Section: Electrochemical Studiesmentioning

confidence: 99%

π‐Face Donor Properties of N‐Heterocyclic Carbenes in Grubbs II Complexes

Leuthäußer

Schmidts

Thiele

et al. 2008

Chemistry A European J

138

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The electron-donating properties of eighteen N-heterocyclic carbenes (N,N'-bis(2,6-dimethylphenyl)imidazol)-2-ylidene and the respective dihydro ligands) with 4,4'-R substituted aryl rings (4,4'-R = NEt2, OMe, Me, H, SMe, F, Cl, Br, I) in the respective Grubbs II complexes were studied using electrochemical techniques. The nature of the 4-R substituent has a strong influence on the RuII/III redox potentials ranging between DeltaE1/2= +0.196 and +0.532 V. Three unsymmetrical Grubbs II complexes with 4-R not equal to 4-R' were also synthesized. Dynamic NMR spectroscopy revealed the restricted rotation around the (NHC)C-Ru bond (DeltaG = 89 kJ mol(-1) at 333 K) resulting in two atropisomers, respectively, with an isomer ratio close to unity. Each of the isomers, that is the two orientations of the 4-R/4-R' substituted mesityl ring with respect to the R=CHPh unit, gives rise to different redox potentials (4-R = NEt2, 4-R' = Br: DeltaE1/2= +0.232 and +0.451 V). In the oxidized Grubbs II complex (4-R = NEt2, H) and in the cathodic isomer the electron rich aryl ring is located above the Ru=CHPh unit. This orientational effect provides clear evidence for strong pi-pi through-space interactions in the RuIII complexes, assuming that the alternative through-bond transfer of electron density is equally efficient in both isomers.

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“…As for 33 (n = 1), the second electron transfer is chemically irreversible for various substituted derivatives [108]. However, the first step remains reversible.…”

Section: Cyclophanes As P-complex Ligandsmentioning

confidence: 93%

Molecular Electrochemistry of Cyclophanes

Speiser

2004

Modern Cyclophane Chemistry

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Synthesis and Properties of Donor-Acceptor-Substituted Metal-Capped Fourfold-Bridged Cyclobutadienophanes

Cited by 12 publications

References 10 publications

Synthesis and Properties of Donor/Acceptor-Substituted Metal-Capped Twofold-Sila-Bridged Cyclobutadieno Superphanes

Synthesis and Properties of Donor/Acceptor-Substituted Metal-Capped Twofold-Sila-Bridged Cyclobutadieno Superphanes

π‐Face Donor Properties of N‐Heterocyclic Carbenes in Grubbs II Complexes

Molecular Electrochemistry of Cyclophanes

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