N-bridged and H-bridged aminoalanes: Single-crystal X-ray structure determinations for the planar dimer {[(Me3Si)2N]2Al(μ-H)}2 and the puckered four-membered ring compound (Me3Si)2N(Me2N)Al(μ-NMe2)2Al(H)N(SiMe3)2

Polyhedron ◽  
1998 ◽  
Vol 17 (23-24) ◽  
pp. 4101-4108 ◽  
Author(s):  
Jerzy F. Janik ◽  
Richard L. Wells ◽  
Arnold L. Rheingold ◽  
Ilia A. Guzei
1992 ◽  
Vol 45 (7) ◽  
pp. 1155 ◽  
Author(s):  
GA Bowmaker ◽  
D Camp ◽  
RD Hart ◽  
PC Healy ◽  
BW Skelton ◽  
...  

The 1 : 1 complexes of the substituted triphenylphosphine ligands mesityldiphenylphosphine and dimesitylphenylphosphine with copper(1) chloride, bromide and iodide have been the subject of single-crystal X-ray structure determinations at 295 K. All six complexes crystallize as air-stable dimeric molecules, [(PPh2Mes)CuX]2 and [ (PPhMes2)CUX]2 with each copper atom in a distorted trigonal PCuX2. coordination environment. Crystals of [(PPh2Mes)CuCl]2 (1) are monoclinic, P21/n, a 9.961(3), b 18.687(6), c 11.009(7) Ǻ, β 114.63(4)°; R was 0.049 for 2450 'observed' reflections. [(PPh2Mes)CuBrI2 (2) is monoclinic, P21/n, a 9.939(2), b 18.832(6), c 11.238(6) Ǻ, β 115.36(3)°; R was 0.046 for 1803 'observed' reflections. [(PPh2Mes)CuI]2.4/3 C6H6 (3) is rhornbohedral, R3, a 36.877(8), c 9.047(5) A; R was 0.039 for 2537 'observed' reflections. Crystals of [(PPhMes2)CuCl]2.2MeCN (4) are triclinic, Pi, a 15.783(7), b 9.570(4), c 8.914(4) Ǻ, α 72.43(3), β 76.37(3), γ 74.03(3)°; R was 0.045 for 3341 'observed' reflections. [(PPhMes2)CuBr]2.3C6H6 (5) is monoclinic, C2/c, a 9.694(6), b 30.15(2), c 20.66(2) Ǻ, β 98.00(7)°; R was 0.047 for 2117 'observed' reflections. [(PPhMes2)CuI]2.2MeCN (6) is orthorhombic, PP1nb, a 11.694(8), b 14.77(1), c 29.76(3) Ǻ; R was 0.049 for 3447 'observed' reflections. Cu-P bond lengths are: 2.196(2) A (1); 2.198(3) Ǻ (2); 2.222(5) and 2.226(5) Ǻ (3); 2.202(1) Ǻ (4); 2.197(3) A (5); 2.201(4) and 2.264(5) Ǻ (6). The geometries of the LCuX2 and CuX2Cu units are compared with data reported for other monomeric and dimeric compounds for both phosphorus- and nitrogen-based ligands L.


1990 ◽  
Vol 43 (10) ◽  
pp. 1657 ◽  
Author(s):  
LM Engelhardt ◽  
BW Skelton ◽  
RV Stick ◽  
DMG Tilbrook ◽  
AH White

A variety of approaches towards the synthesis of lincosamine, a derived portion of the antibiotic lincomycin , are reported. Initial approaches involved the intramolecular delivery of a nitrogen atom ( trichloroacetimidate , trichloroacetylcarbamate , carbamate, 2-amino-2- phenylacetate ) attached to O4 onto C6 of a 6,7-anhydrooctoside. Later approaches, albeit more direct but again largely unsuccessful, involved the Sharpless titanium(IV)-mediated nucleophilic opening of a suitable 6,7-anhydrooctose, and the Sharpless oxyamination and the aziridination of suitable octenoses . As an aid to the structure elucidation of several compounds encountered in this work, single-crystal X-ray structure determinations are reported for methyl 6,7-anhydro-2,3-di-O-benzyl-8-deoxy-α-D-threo-D-galacto-octopyranoside , methyl 6,7-anhydro-2,3-di-O-benzyl-8-deoxy-α-D-threo-D-gluco-octopyranoside and 7-azido-7-deoxy-1,2:3,4-di-O-isopropylidene-β-L-erythro-Dgalacto-octose.


1995 ◽  
Vol 50 (12) ◽  
pp. 1811-1817 ◽  
Author(s):  
Max Herberhold ◽  
Christian Köhler ◽  
Wolfgang Milius ◽  
Bernd Wrackmeyer

N,N′-Dialkyl sulfur diimides (1), R(NSN)R [R = Me (a), Et (b), nPr (c), nBu (d)] react with cyclic bis(amino)stannylenes such as 1,3-di-tert-butyl-4,4-dimethyl-1,3,4,2λ2-diazasilastannetedine (2) or 1,3-di-tert-butyl-4,4,5,5-tetramethyl-1,3,4,5,2λ2-diazadisilastannolidine (3) in a 2:1 ratio to give the new spiro-tin(IV) compounds 5a-d, 6b and 6c, built from the respective cyclic bis(amino)stannylene and a seven-membered ring in which the two sulfur diimide groups are coupled via a N-N bond and across the tin atom. A 1:1 adduct 4 is proposed as an intermediate which is the final product 4e in the case of R = tBu (1e). The products were characterized by multinuclear magnetic resonance (1H, 13C, 15N, 29Si, 119Sn NMR), and in the case of 5c the molecular structure was determined by single crystal X-ray structure analysis [monoclinic, space group C2/c ; a = 1504.1(3), b = 1393.3(3), c = 1688.6(3) pm; β = 115.71(3)°].


1975 ◽  
Vol 30 (5-6) ◽  
pp. 462-464 ◽  
Author(s):  
R. Haegele ◽  
W. Verscharen ◽  
D. Babel

The parameters of complete X-ray structure determinations are given for the fluoridesRb2NaFeF6 and Rb2KFeF6 (cubic), Cs2NaCrF6 and Cs2NaFeF6 (hexagonal-rhom-bohedral) and Cs2LiGaF6 (hexagonal). Space group and lattice constants of the monoclinic cyanides Cs2BFe(CN)6 (B = Na, K, Rb) are reported as well.


1979 ◽  
Vol 32 (9) ◽  
pp. 1931 ◽  
Author(s):  
H Becker ◽  
K Gustafsson ◽  
CL Raston ◽  
AH White

Single-crystal X-ray diffraction structure determinations are reported for three reaction products and photoisomers formed from reactions between an o-diphenoquinone valence isomer and primary and secondary amines, namely: 3,5-di-t-butyl-7-(3,5-di-t-butyl-2-hydroxyphenyl)-1-methyl-2,3-dihydro-1H-azepin-2-one (8; R1 = R2 = But, R3 = Me), its photochemical isomerization product 4,6-di-t-butyl-1-(3,5-di-t-butyl-2-hydroxyphenyl)-2-methyl-2-azabicyclo[3,2,0]hept-6-en-3-one (9; R1 = R2 = But, R3 = Me) and 4',5,7-tri-t-butyl-3'-(2,2-dimethylpropionyl)-1'-methylspiro[benzofuran-3(2H)-2'- pyrrolidinel-2,5'-dione (12; R1 = R2 = But, R3 = Me).


2005 ◽  
Vol 58 (3) ◽  
pp. 199 ◽  
Author(s):  
Ethan D. Goddard-Borger ◽  
Brian W. Skelton ◽  
Robert V. Stick ◽  
Allan H. White

The use of 1H NMR spectroscopy, in tandem with X-ray crystallography, has cast light on the conformation of the 1,6-disulfide-bridged derivatives of d-gluco-, d-manno-, d-allo-, d-galacto-, and d-talo-pyranose. A similar investigation was performed on the thiosulfinate derived from the d-gluco disulfide. Single-crystal X-ray structure determinations are reported for (1S,5S,6S,7S,8R)-6,7,8-tribenzoyloxy-9-oxa-2,3-dithiabicyclo[3.3.1]nonane, (1S,5S,6S,7R,8R)-6,7,8-tribenzoyloxy-9-oxa-2,3-dithiabicyclo[3.3.1]nonane, and (1S,2S,5S,6S,7S,8R)-6,7,8-triacetoxy-9-oxa-2,3-dithiabicyclo[3.3.1]nonane 2-oxide.


1980 ◽  
Vol 33 (2) ◽  
pp. 313 ◽  
Author(s):  
PR Jefferies ◽  
BW Skelton ◽  
B Walter ◽  
AH White

Following the suggestion made earlier, on the basis of solution spectroscopy, that a number of eriostyl/nitrobenzoate compounds form charge-transfer self-complexes, a number of these have been investigated structurally by single-crystal X-ray diffraction methods in order to ascertain the presence or otherwise of such interactions in the solid state. The substances thus studied were eriostyl 3,5-dinitrobenzoate (1), eriostyl p-nitrobenzoate (2), tetrahydroeriostyl 3,5-dinitrobenzoate (3), and eriostemyl 3,5-dinitrobenzoate (4);* structure determinations in all cases, although displaying the presence of strong charge-transfer interactions from the two moieties of each molecule, show that the interactions in the solid state are intermolecular in nature.


1988 ◽  
Vol 43 (11) ◽  
pp. 1416-1426 ◽  
Author(s):  
Hans H. Karsch ◽  
Armin Appelt ◽  
Brigitte Deubelly ◽  
Karin Zellner ◽  
Jürgen Riede ◽  
...  

The lithium phosphinomethanides LiCH(X)(PMe2) (X = H, PMe2 SiMe3) react with Me3SiCl to give silylsubstituted phosphinomethanes CH(X)(PMe2)(SiMe3). The latter are metalated by LiR (R = tBu, nBu). This metalation is facilated by the presence of Me2NCH2CH2NMe2 (TMEDA). X-ray structure determinations of {(TMEDA)Li[CH(PMe2)(SiMe3)]}2 (3b) and (TMEDA){Li[C(PMe2)(SiMe3)2]}2 (5b) show the marked influence of increasing silyl substitution on the structures of lithium phosphinomethanides: the Li-C contacts are weakened, whereas phosphorus forms additional (bridging) Li···P contacts to the second Li atom in the dimeric arrangements. In 3b, a six-membered ring in twist conformation is formed by head-to-tail dimerization. Likewise, 5b forms a six-membered ring, in this case by head-to-head dimerization. however, which may be regarded as a complex of a chelating phosphinomethyl lithiate ligand to [(TMEDA)Li]+ .


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