Calculations of Lithium+ Carborane Complexes

Newtonpsilas equations of motion and a Universal Force Field with a charge equilibration scheme implemented in our molecular dynamics program TINK and standard ab initio codes have been used on high performance computers (HPC) at the Arctic Region Supercomputing Center (ARSC) to theoretically study: (i) the structure and dynamics of Li⁺CH₂=CH-(CH₂)_n-2-C(BMe)₁₁ ^- self catalyst and the alkene polymerization LiCB₁₁Me₁₂ catalyst, and (ii) the unusual pK_a values of substituted Li⁺CH₂=CH-(CH₂)_n-2-C(BMe)₁₁- carborane salts that were observed experimentally in our laboratory. The parent compound (CB₁₁H₁₂ ^-) exhibits a pK_a of 21.8 while the fluorine substituted compound (12-F-CB₁₁H₁₁ ^-) has a pK_a of 34. This is an amazing observation. Molecular dynamics calculations have now offered a possible explanation.