TY - JOUR
T1 - Trinuclear Cluster Complexes Containing the Furyne Ligand: Synthesis, Structure, and Properties of the Cycloalkyne Complexes (CpCo)n(Cp*Co)3-n(CO)(μ3-η2-C4H4O) (n = 3, 2)
AU - King, William D.
AU - Barnes, Craig E.
AU - Orvis, Jeffery A.
PY - 1997/3/13
Y1 - 1997/3/13
N2 - Cyclopentadienyl-based tricobalt clusters containing the cyclic furyne ligand, CH2C⋮CCH2O, have been prepared by the pyrolysis of the butynediol complexes (CpCo)3(CO)(RCCR), 1, and (CpCo)2(Cp*Co)(CO)(RCCR), 2 (R = CH2OH). The solid state structures of the furyne complexes, (CpCo)3(CO)(μ3-η2-CH2C⋮CCH2O), 3, and (CpCo)2(Cp*Co)(CO)(μ3-η2-CH2C⋮CCH2O), 4, verify the presence of the five-membered heterocycle, which formally contains an alkyne group interacting with the tricobalt framework. Chemically and electrochemically reversible one-electron oxidative and reductive couples are observed for 3 at +0.235 and −1.466 V (CH2Cl2 solution, Pt electrode, Fc0/+1 = +0.482 V), respectively, which are similar to redox features observed for noncyclic analogues. At 171 K, the methylene signals of the furyne ligand in 4 are observed as doublets, indicating that furyne rotation is slow at this temperature. Reversible coalescence of the methylene signals occurs at 195 K, and at room temperature, a single sharp methylene resonance is observed. Total line shape analysis of the coalescing spin system yields the activation parameters for the motion of the furyne ring:  Δ G ⧧ (300 K) = 39.4(2) kJ/mol, Δ S ⧧ = −18(2) J/mol, and Δ H ⧧ = 34.0(4) kJ/mol.
AB - Cyclopentadienyl-based tricobalt clusters containing the cyclic furyne ligand, CH2C⋮CCH2O, have been prepared by the pyrolysis of the butynediol complexes (CpCo)3(CO)(RCCR), 1, and (CpCo)2(Cp*Co)(CO)(RCCR), 2 (R = CH2OH). The solid state structures of the furyne complexes, (CpCo)3(CO)(μ3-η2-CH2C⋮CCH2O), 3, and (CpCo)2(Cp*Co)(CO)(μ3-η2-CH2C⋮CCH2O), 4, verify the presence of the five-membered heterocycle, which formally contains an alkyne group interacting with the tricobalt framework. Chemically and electrochemically reversible one-electron oxidative and reductive couples are observed for 3 at +0.235 and −1.466 V (CH2Cl2 solution, Pt electrode, Fc0/+1 = +0.482 V), respectively, which are similar to redox features observed for noncyclic analogues. At 171 K, the methylene signals of the furyne ligand in 4 are observed as doublets, indicating that furyne rotation is slow at this temperature. Reversible coalescence of the methylene signals occurs at 195 K, and at room temperature, a single sharp methylene resonance is observed. Total line shape analysis of the coalescing spin system yields the activation parameters for the motion of the furyne ring:  Δ G ⧧ (300 K) = 39.4(2) kJ/mol, Δ S ⧧ = −18(2) J/mol, and Δ H ⧧ = 34.0(4) kJ/mol.
UR - https://digitalcommons.georgiasouthern.edu/chem-facpubs/156
UR - https://doi.org/10.1021/om960867z
U2 - 10.1021/om960867z
DO - 10.1021/om960867z
M3 - Article
SN - 0276-7333
VL - 16
JO - Organometallics
JF - Organometallics
ER -