1. Crystal structure of N3P3Cl4[HN(CH2)3NH] at 133 K: a spiro cyclic cyclotriphosphazene
2. Crystal data: N3P3[NMe(CH2)3NMe]Cl4 (3), M, = 376.92, F(000) = 760 orthorhombic, space group P212121, a, = 7.925(1), b, = 13.585(1), c, = 14.204(1) Å, U, = 1529.13 Å3, Z, = 4, Dc, = 1.637 g/cm3, Λ(Mo-Kα) = 0.71069 Å, μ = 9.86 cm−1, R, = 0.039 for 1563 unique reflections with I>1.5[sgrave](I); N4P4(NHEt)6(NEt) (6), M, = 487.46, F(000) = 1048, triclinic, space group PI, a, = 18.947(6), b, = 12.349(2), c, = 12.352(3) Å, α = 114.82(2), β = 88.34(2), γ = 94.17(2)°, U, = 2616.14 Å3, Z, = 4, Dc, = 1.237 g/cm3, Λ(Cu-Kα) = 1.54178 Å, μ = 27.31 cm−1, R = 0.094 for 4988 unique reflections with I1.5[sgrave](I); N4P4(NMe2)5(NHEt)(NEt) (5), M = 487.46, F(000) = 2096, monoclinic, space group C2/c, a = 10.583(2), b = 17.535(4), c = 28.195(4) Å, β = 94.26(1)°, U = 5217.77 Å3, Z = 8, Dc = 1.241 g/cm3, Λ(Cu-Kα) = 1.54178 Å, μ = 27.39 cm−1, R = 0.042 for 3442 unique reflections with I1.5[sgrave](I). The intensities were measured on an Enraf-Nonius CAD-4 diffractometer in the manner described elsewhere3 using graphite monochromatized Mo-Kα [for (3)] and Ni-monochromatized Cu-Kα [for (5) and (6)] radiations in an ω/2θ scan mode in the range θ1.5–25 and θ3–65° respectively. The structures were solved by direct methods applying SHELX/844 and refined by least-squares. All the non-hydrogen atoms were refined anisotropically, all the hydrogen atoms, for (3) and (5) and some of the hydrogen atoms for (6), located from difference maps, isotropically. Empirical absorption corrections were applied for (5)5 and (6)5,6 The atomic co-ordinates for this work are available on request from the Director of the Cambridge Crystallographic Data Centre, University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW. Any request should be accompanied by the full literature citation for this communication.18
3. Synthesis and x-ray crystal structures of hexakis(trimethylphosphine)tris-.mu.-methylene-diruthenium(III) and its mono- and dicationic derivatives
4. Sheldrick , G. M. personal communication
5. An empirical method for correcting diffractometer data for absorption effects