Supermesitylphosphane" [i.e. (2,4,6-t Bu 3 C 6 H 2 )PH 2 ) Mes*-PH 2 ] 1 has been widely used during the past years as a sterically demanding, phosphorus-containing ligand both in main-group 2 and in transition-metal chemistry. 3 The main transfer reagent typically employed was either the lithium salt Mes*P(H)Li‚ 3THF 3 or the phosphane itself. 2 It is noteworthy that only monometalation of Mes*PH 2 can be achieved according to earlier reports. 4 Interestingly, no information is available in the literature on the synthesis, isolation, and characterization of other alkali metal salts of this particular ligand. Here we wish to report the potassium derivative of supermesitylphosphane, thus representing a first report on a heavier alkali metal salt of a primary phosphane.In light of the dearth of structural data 5 available on molecular phosphide species of the heavier alkali metals of the general formula M[PR 2 ] or M[PRH], we were interested in investigating the accessibility as well as structural aspects of the potassium derivative of supermesitylphosphane. This lack of information available on solid-state structures of salts of heavier congeners of alkali metals is rather surprising since several structural studies on lithium phosphides have appeared since the early eighties. 6 These studies have shown that LiPR 2 species can exhibit a variety of molecular structures depending on the substituent R on phosphorus and the type of solvent and/or donor ligand D employed. Variation in R and D vastly affects the solid-state structures of these species. The interest in heavier alkali metal salts of phosphides 7 as well as their solid-state structures arises from their synthetic potential as transfer agents as well as fundamental and theoretical aspects. Also, alkali metal salts of [PRH] anions are of interest since they are potential transfer agents toward the formation of complexes that can be used as suitable precursors for generating phosphinidene species of the early transition metals 3 and the actinides. 8 Reaction of potassium hydride with 1 equiv of supermesitylphosphane in tetrahydrofuran solution at room temperature forms the title complex KP(H)Mes* (1) in 80% yield, 9 which was found to be insoluble in hexanes as well as in aromatic solvents.The molecular structure 10 of the pale yellow potassium derivative 1 has an extended, one-dimensional polymeric ladder- † Technische Universität München. ‡ University of Delaware. (1) (a) Cowley, A. H.; Norman, N. C.; Pakulski, M.; Becker, G.; Layh, M.; Kirchner, E.; Schmidt, M. Inorg. Synth. 1990, 27, 235. (b) Yoshifuji, M.; Shima, I.; Inamoto, N.; Hirotsu, K.; Higuchi, T. Cowley, A. H.; Kilduff, J. E.; Newman, T. H.; Pakulski, M. J. Am. Chem. Soc. 1982, 104, 5820. (5) Allen, F. H.; Davies, J. E.; Galloy, J. J.; Johnson, O.; Kennard, O.; Macrae, C. F.; Mitchell, E. M.; Mitchell, G. F.; Smith, J. M.; Watson, D. G. J. Chem. Inf. Comput. Sci. 1991, 31, 187. (6) (a) Bartlett, R. A.; Olmstead, M. M.; Power, P. P.; Sigel, G. A. Inorg. Chem. 1987Chem. , 26, 1941 Bartlett, ...
