@article {124, title = {An Experimental Solution to the "Missing Hydrogens" Question Surrounding the Macropolyhedral 19-Vertex Boron Hydride Monoanion [B19H22](-), a Simplification of Its Synthesis, and Its Use As an Intermediate in the First Example of syn-B18H22 to anti-B18H22}, journal = {Inorganic Chemistry}, volume = {49}, year = {2010}, month = {03/2010}, pages = {4092{\textendash}4098}, type = {Full article}, chapter = {4092}, abstract = {

The macropolyhedral [B19H22]- monoanion 1 and the dianion [B19H21]2-2 are synthesized in consistent 86-92\% yields by the reaction of [PSH]+[syn-B18H21]- with BH3(SMe2) in 1,2-Cl2C2H4 at 72 {\textdegree}C. [{\textquoteleft}PS{\textquoteright} is an abbreviation for {\textquoteleft}Proton Sponge{\textquoteright}, 1,8-bis-(dimethylamino)naphthalene. {\textquoteleft}PSH{\textquoteright} is its protonated derivative.] The molecular structures of 1 and 2 were elucidated as their [PS{BH2}]+ and [PS{BH2}]2+ salts 1a and 2a by single-crystal X-ray diffraction studies, in which all atoms were located, and supported by mass spectrometric analyses together with calculations of the cluster molecular geometries (ab ignitio and/or DFT) and of 11B chemical shifts based on GIAO-DFT shielding tensors. Acidification of dianion 2 with CF3COOH in acetonitrile, H2SO4 in dichloromethane, or aqueous HCl results in the clean formation of the monoanion [B19H22]-1. Conversely, shaking a concentrated acetonitrile solution of 1 in 0.5 M aqueous NaOH cleanly yields the [B19H21]2- dianion 2. Reaction of a dichloromethane solution of 1 with a 36\% aqueous solution of HCHO in the presence of H2SO4 quantitatively converts 1 at room temperature to a 1:1 mixture of the syn- and anti-isomers of B18H22. This cluster dismantling process is the first example of a syn- to anti-B18H22 isomer conversion.

}, keywords = {anti-B18H22, conversion, macropolyhedral borane clusters, syn-B18H22}, doi = {https://doi.org/10.1021/ic901976y}, url = {http://pubs.acs.org/doi/abs/10.1021/ic901976y}, author = {Michael G S Londesborough and Jonathan Bould and Tomas Base and Drahomir Hnyk and Mario Bakardjiev and Josef Holub and Ivana Cisarova and John D Kennedy} }