From Simple Monopyridine Clusters [Mo6Br13(Py-R)][n-Bu4N] and Hexapyridine Clusters [Mo6X8(Py-R)6][OSO2CF3]4 (X = Br or I) to Cluster-Cored Organometallic Stars, Dendrons, and Dendrimers
摘要:
Hexasubstitution of apical triflate ligands in the octahedral clusters [M](2)[Mo6X8(CF3SO3)(6)] (M = n-BU4N or Cs, X = Br or 1) and monosubstitution in [n-Bu4N](2)[Mo6Br13(CF3SO3)] was carried out in tetrahydrofuran at 60 degrees C with simple pyridines and then extended to organometallic pyridines, yielding cluster-cored stars, and to dendronic polyallyl and polyferrocenylpyridines, yielding cluster-cored polyallyl and polyferrocenyl dendrimers and dendrons. The orange pyridine-substituted clusters, whose pyridine protons are deshielded in H-1 NMR (a practical tool for characterization), are air-stable and thermally stable with simple pyridines, light- and air-sensitive with organometallic pyridines, and air-fragile and thermally fragile with large dendronized pyridines.