TY - JOUR
T1 - Mixed-metal cluster chemistry. 16. Syntheses of oligourethanes containing clusters in the backbone
AU - Lucas, Nigel T.
AU - Humphrey, Mark G.
AU - Rae, A. David
PY - 2001/8/28
Y1 - 2001/8/28
N2 - Bis(hydroxyalkylcyclopentadienyl)-containing mixed molybdenum-iridium clusters Mo2Ir2-(CO)10{η-C5 H4(CH2)xOH}2 [x = 2 (1), 10] react with alkyl or aryl 1, ω-diisocyanates OCNRNCO [R = (CH2)y (y = 4, 6, 12), trans-1,4-cyclohexyl, or 4-C6H4CH2-4-C6H4] to form oligourethanes with transition metal clusters in the oligomer backbone. Characterization of the cluster-containing oligourethanes is aided by spectral comparison with model cluster diurethanes Mo2Ir2(CO)10[η-C5 H4(CH2)2OC(O)NHRH}2 [R = (CH2)y [y = 4 (6), 6, 12], trans-1,4-cyclohexyl] prepared from reaction between the cluster diol 1 and alkyl isocyanates HRNCO. The precursor diol cluster 1 and cluster diurethane 6 have been characterized by single-crystal X-ray diffraction studies. The extent of polymerization has been assessed by gel permeation chromatography, with little dependence on diisocyanate precursor linker R but strong dependence on alkylcyclopentadienyl linker length (CH2)x, suggesting that the steric influence of the bulky dimolybdenum-diiridium cluster core and co-ligands is the most important factor governing extent of polymerization. Supporting this assessment, the considerably more sterically hindered precursor 2-butyn-1,4-diol-substituted cluster Mo2Ir2{μ4-η2 -C2(CH 2OH)2}(CO)8(η -C5H5)2 fails to react to any significant extent with 1,6-diisocyanatohexane.
AB - Bis(hydroxyalkylcyclopentadienyl)-containing mixed molybdenum-iridium clusters Mo2Ir2-(CO)10{η-C5 H4(CH2)xOH}2 [x = 2 (1), 10] react with alkyl or aryl 1, ω-diisocyanates OCNRNCO [R = (CH2)y (y = 4, 6, 12), trans-1,4-cyclohexyl, or 4-C6H4CH2-4-C6H4] to form oligourethanes with transition metal clusters in the oligomer backbone. Characterization of the cluster-containing oligourethanes is aided by spectral comparison with model cluster diurethanes Mo2Ir2(CO)10[η-C5 H4(CH2)2OC(O)NHRH}2 [R = (CH2)y [y = 4 (6), 6, 12], trans-1,4-cyclohexyl] prepared from reaction between the cluster diol 1 and alkyl isocyanates HRNCO. The precursor diol cluster 1 and cluster diurethane 6 have been characterized by single-crystal X-ray diffraction studies. The extent of polymerization has been assessed by gel permeation chromatography, with little dependence on diisocyanate precursor linker R but strong dependence on alkylcyclopentadienyl linker length (CH2)x, suggesting that the steric influence of the bulky dimolybdenum-diiridium cluster core and co-ligands is the most important factor governing extent of polymerization. Supporting this assessment, the considerably more sterically hindered precursor 2-butyn-1,4-diol-substituted cluster Mo2Ir2{μ4-η2 -C2(CH 2OH)2}(CO)8(η -C5H5)2 fails to react to any significant extent with 1,6-diisocyanatohexane.
UR - http://www.scopus.com/inward/record.url?scp=0035964530&partnerID=8YFLogxK
U2 - 10.1021/ma0104480
DO - 10.1021/ma0104480
M3 - Article
SN - 0024-9297
VL - 34
SP - 6188
EP - 6195
JO - Macromolecules
JF - Macromolecules
IS - 18
ER -