Thallium salts of monoanionic metallacarboranes were generated in situ and utilized as synthons yielding novel dinuclear metallacarboranes with metal-metal bonding interaction.
$[3,3,3-(CO)_3-closo-3,1,2-MnC_2B_9H_{11}]Tl$ (1) was prepared from the equimolar reaction system of $Mn(CO)_5Br/Tl_2C_2B_9H_{11}$ at reflux condition and identified by in situ$^{11}$B NMR. 1 was employed to explore its reactivity with various metal halides.
$[3-(PPh_3)-closo-3,1,2-AgC_2B_9H_{11}]Tl$ (3), which was prepared by reacting $AgBr(PPh_3)_2$ with $Tl_2C_2B_9H_{11}$, was used as cage transfer reagent as well as direct complexation reagent. The reaction of 3 with trans-$Rh(CO)(PPh_3)_2Cl$ afforded cage-transferred bimetallic complex $[exo-8-{(μ-H)Ag(PPh_3)]-3-(CO)-3-(PPh_3)-closo-3,1,2,-RhC_2B-9H_{10}]$ (4). The molecular structure of 4ㆍTHF was established by spectroscopic analysis and single crystal X-ray diffraction study $(Rh_3-Ag2.651$ (2) Å, $Ag-HB8 1.971(159 Å), $Rh3-Ag-P2 156.8(2) Å).
