MOLECULAR-STRUCTURES OF THE HEAVIER ALKALI-METAL SALTS OF SUPERMESITYLPHOSPHANE - A SYSTEMATIC INVESTIGATION

The molecular structures of the rubidium and cesium derivatives of sup ermesitylphosphane [i.e., (2,4,6-(t)-Bu3C6H2)PH2 = (t)Bu(3)MesPH(2)] a s well as several base adducts of these are reported. Sodium hydride, potassium hydride, rubidium metal, and cesium metal react with (t)Bu(3 )MesPH(2) in tetrahydrofuran solution at room temperature to produce M PRH salts 1-4 [M = Na (1), K (2), Rb (3), Cs (4); R = (t)Bu(3)Mes] in good yields. X-ray-quality crystals of 2 and 3 were obtained by slow e vaporation of solutions of the corresponding MP(H)(t)Bu(3)Mes species dissolved in toluene/thf. Complex 4 was crystallized from hot toluene. On the other hand, slow evaporation of a toluene/tetrahydrofuran solu tion of CsP(H)(t)Bu(3)Mes (4) produces crystals of the composition {[C sP(H)(t)Bu(3)Mes](2)(mu-THF)(0.9).toluene}(x) (5). Crystallization of 4 in the presence of pyridine yields crystals of {[CsP(H)(t)Bu(3)Mes]( 2)(mu-pyridine)}(x) (6). Also, crystallization of complexes 3 and 4 fr om toluene/N-methylimidazole (N-MeIm) gives the isomorphous complexes {[RbP(H)(t)Bu(3)Mes](2)(mu-N-MeIm)}(x) (7) and {[CsP(H)(t)Bu(3)Mes](2) (mu-N-MeIm)}(x) (8), respectively. However, crystallization of 4 from toluene in the presence of bidentate or polydentate bases such as dime thoxyethane or pentamethyldiethylenetriamine does not result in incorp oration of these bases into the lattice. Instead, the toluene solvate {[CsP(H)(t)Bu(3)Mes](2)(eta(3)-toluene)(0.5)}(x) (9) is obtained. On t he other hand, crystallization of 4 from toluene/ethylenediamine gives the base adduct {[CsP(H)(t)Bu(3)Mes](2)(mu-ethylenediamine)}(x) (10). Complex 3 crystallizes in the triclinic space group P (1) over bar. C rystal data for 3 at 218 K: a = 6.71320(10) Angstrom, b = 10.5022(2) A ngstrom, c = 14.9733(3) Angstrom, alpha = 91.3524(13)degrees, beta = 1 02.5584(13)degrees, gamma = 107.7966(14)degrees; Z = 1; R-1 = 6.55%. C omplex 4 crystallizes in the triclinic space group P (1) over bar. Cry stal data for 4 at 223 K: a = 7.0730(14) Angstrom; b = 10.395(2) Angst rom; c = 14.933(2) Angstrom; alpha = 81.97(1)degrees; beta = 76.35(2)d egrees; gamma = 71.824(14)degrees; Z = 1; R-1 = 4.56%. Complex 5 cryst allizes in the monoclinic space group P2(1)/c. Crystal data for 5 at 2 43 K: a = 15.039(2) Angstrom; b = 16.152(3) Angstrom; c = 20.967(5) An gstrom; beta = 91.53(2)degrees; Z = 4; R-1 = 4.83%. Complex 6 crystall izes in the orthorhombic space group Pbcn. Crystal data for 6 at 298 K : a = 14.686(2) Angstrom; b = 21.295(5) Angstrom; c = 28.767(5) Angstr om; Z = 8; R-1 = 5.61%. Complex 7 crystallizes in the orthorhombic spa ce group Pbcn. Crystal data for 7 at 218 K: a = 14.5533(2) Angstrom; b = 21.4258(5) Angstrom; c 28.5990(5) Angstrom; Z = 8; R-1 = 4.61%. Com plex 8 crystallizes in the orthorhombic space group Pbcn. Crystal data for 8 at 219 K: a = 14.6162(2) Angstrom; b = 21.3992(3) Angstrom; c = 28.7037(2) Angstrom; Z = 8; R-1 = 3.57%. Complex 9 crystallizes in th e triclinic space group P (1) over bar. Crystal data for 9 at 293 K: a = 11.147(4) Angstrom; b = 14.615(4) Angstrom; c = 14.806(5) Angstrom; alpha = 70.57(3)degrees; beta = 71.85(3)degrees; gamma = 172.93(2)deg rees; Z = 2; R-1 = 5.13%. Complex 10 crystallizes in the triclinic spa ce group P (1) over bar. Crystal data for 10 at 173 K: a = 10.5690(4) Angstrom; b = 15.0376(5) Angstrom; c = 15.3643(5) Angstrom; alpha = 11 1.8630(10)degrees; beta = 100.4120(10)degrees; gamma = 97.4820(2)degre es; Z = 2; R-1 = 4.87%. A common feature of the molecular structures o f complexes 2-10 is an infinitely extended polymeric ladder framework in the solid state. Both solution and solid-state NMR data are present ed.