Utility of Anhydrous Neodymium Nitrate as a Precursor to Extended Organoneodymium Nitrate Networks

Hydrated neodymium nitrates can be readily transformed to anhydrous ether solvates which react with cyclopentadienyl reagents to make organometallic nitrate complexes with variable degrees of oligomerization. Heating Nd(NO₃)₃(H₂O)₆ in tetrahydrofuran at reflux, removal of solvent, drying at 100 °C under high vacuum, and addition of hot THF generates Nd(NO₃)₃(THF)₃, 1. Using dimethoxyethane, Nd(NO₃)₃(DME)₂, 2, can be obtained similarly. Addition of NaC₅Me₅ to 1 generates (C₅Me₅)Nd(NO₃)₃(THF)Na(THF)_x complexes which crystallize as {[(C₅Me₅)(NO₃)₂Nd(THF)(μ-NO₃)]₂Na(THF)₄}[Na(THF)₆], 3, or [(C₅Me₅)Nd(THF)(μ-NO₃)₃Na(THF)₂]_n, 4, depending on the conditions. The trimetallic Nd₂Na unit in 3 forms an extended system in 4 via bridging nitrates. Addition of KC₅Me₅ and 18-crown-6 to 1 generates another extended complex [(C₅Me₅)Nd(THF)(NO₃)(μ-NO₃)₂K(18-crown-6)]_n, 5, in which an 18-crown-6 ligated potassium links neodymium centers via two bridging nitrates and an agostic interaction between a C₅Me₅ methyl group and potassium.