From Simple Monopyridine Clusters [Mo_6Br_(13)(Py-R)][n-Bu_4N] and Hexapyridine Clusters [Mo_6X_8(Py-R)_6][OSO_2CF_3]_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[Mo_6X_8(CF_3SO_3)_6] (M = n-Bu_4N or Cs,X = Br or I) and monosubstitution in [n-Bu_4N]_2[Mo_6Br_(13)(CF_3SO_3)] was carried out in tetrahydrofuran at 60 deg 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 ~1H 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.