Browsing by Author "Smith, JD"

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    Metal complexes of guanidine-substituted alkyl ligands
    Coles, MP; Sözerli, SE; Smith, JD; Hitchcock, PB
    Single-crystal X-ray diffraction of MC(SiMe3)(2)(SiMe(2)hpp) (M = Li, K; hppH = 1,3,4,6,7,8,-hexahydro-2H-pyrimido[1,2-a]pyrimidine) showed nonsolvated organometallic compounds in which the iminonitrogen of the guanidine forms strong intramolecular bonds to generate six-membered metallacycles.
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    An Ether-Free, Internally Coordinated Dialkylcalcium(II) Complex
    Coles, MP; Sözeril, SE; Smith, JD; Hitchcock, PB; Day, IJ
    The alkylpotassium compound KC{SiMe(3)}(2){SiMe(2)hpp} (hppH = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) reacts with a slurry of CaI(2) in toluene to give the internally coordinated dialkylcalcium(II) complex Ca(C{SiMe(3)}(2){SiMe(2)hpp})(2). The molecular structure in the solid state shows short Ca-N and long Ca-C bonds and a wide C-Ca-C angle. The (1)H and (13)C NMR spectra suggest that the metallacycle is transiently opened in toluene at room temperature.
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    Attachment to manganese or cobalt of a bulky tri(organosilyl)methyl ligand containing an NMe2 or an OMe donor group
    Al-Juaid, SS; Eaborn, C; El-Hamruni, SM; Hitchcock, PB; Smith, JD; Can, SES
    The organolithium compound Li(THF)(2){C(SiMe3)(2)(SiMe2NMe2)} reacted with one equivalent of MnCl2 to give [Mn(mu-Cl){C(SiMe3)(2)(SiMe2NMe2)}](2) (4) and with 0.5 equivalent of MnCl2 to give Mn{C(SiMe3)(2)(SiMe2NMe2)}(2) together with a small amount of the Mn-III compound [Mn(mu-O){C(SiMe3)(2)(SiMe2NMe2)}](2) (6) formed by adventitious admission of air. With CoBr2, the compound [Co(mu-Br){C(SiMe3)(2)(SiMe2NMe2)}](2) (7) was obtained. The reaction between the lithium compound Li(THF)(2){C(SiMe3)(2)(SiMe2OMe)} and MnCl2 in THF gave [Mn(THF)(mu-Cl){C(SiMe3)(2)(SiMe2OMe)}](2) (5). The crystal structures of compounds 4, 5, 6 and 7 were determined. Compounds 4 and 5 are the first manganese analogues of Grignard reagents containing Mn-C sigma-bonds to be characterised in the solid state. (C) 2002 Elsevier Science B.V. All rights reserved.
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    Tin and Mercury Compounds Supported by a Bulky Organometallic Ligand Incorporating a Pendant Guanidine Functionality
    El-Hamruni, SM; Sözerli, SE; Smith, JD; Coles, MP; Hitchcock, PB
    The structure of a triclinic form of the organolithium derivative LiR, R = C(SiMe3)(2)(SiMe2{hpp}) (1) (hppH = 1,3,4,6,7,8,-hexahydro-2H-pyrimido[1,2-alpha] pyrimidine) comprises dimers [1](2) held together by Li center dot center dot center dot H3C interactions like those in the polymeric structure [1](infinity) of the previously described orthorhombic form. Compound 1 reacts with the chlorides MCl2 (M = Hg or Sn) to give compounds HgRCl (2) or SnRCl (3), which have been characterised by NMR spectroscopy and X-ray crystallography. The structural parameters and conformations of the metallacycles MRLn are compared with those in related compounds containing bulky organosilicon ligands with pendant nitrogen donors. Compound 3 reacts with Li[P{H}Ar*] (Ar* = 2,4,6-tBu(3)C(6)H(2)) to give the crowded phosphanide SnR(P{H} Ar*) (4).