Synthesis and X-ray Crystal Structure Determination of the First Potassium Salt of a Primary Phosphane:  [KP(H)Mes*]_x

Abstract

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, ...

Amido-Komplexe von Mangan(II). Synthese und Kristallstrukturen von [Mn(NPh2)2(THF)]2 und Na2[Mn(NPh2)4] · 2 C7H8

“…1 wiedergegebene zentrosymmetrische dimere Moleku È lstruktur, in der die beiden Mangan-Atome u È ber nahezu gleich lange Mn±N-Bindungen von 217,6 und 218,9(2) pm verknu È pft sind. Deutlich ku È rzer sind naturgema È û die Mn±N-Bindun- (25), in Schema 1 mit ---symbolisiert) und andererseits mit zwei Phenylringen von zwei benachbarten Anionen (C(1)±C (15), in Schema 1 mit´´´symbolisiert) verknu È pft. Dabei sind alle 12 Na ---C-Kontakte der chelatisierenden Phenylringe mit Absta È nden von 277,9 bis 329,4(4) pm deutlich ku È rzer als die Summe der van der Waals-Radien von 347 pm (Tabelle 3), wa È hrend dies bei nur je zwei Na´´´C-Kontakten zu den Nachbar-Anionen mit Absta È nden von 308,5 und 315,2(4) pm der Fall ist.…”

Phosphanides of the Heavier Alkali Metals

“…Polymeric ladder structures, based on alkali metal ± phosphorus bonds, predominate. [6] The general principles underlying this pattern of structures were defined in a seminal paper [7] many years ago, and they apply to most groups of oligomeric compounds containing an element from Groups 1 ± 3 (M) and one from Groups 15 ± 17 (E). Firstly, for the formation of higher from lower oligomers, the enthalpy change associated with the formation of additional M ± E bonds must be sufficient to overcome the unfavorable entropic contribution to the free energy.…”

Synthese und Kristallstruktur von [KNPPh3]6 · 4 C7H8

“…Sie variieren zum Beispiel bei K(1)´´´C(49-54) zwischen 304,8 und 392,0(7) pm, bei K(2)´´´C(109-114) zwischen 338 und 378(1) pm. Dies entspricht recht gut Erfahrungswerten anderer K +´´´A romat-Wechselwirkungen [11,12]. …”