Phosphaniminato-Komplexe von Bor. Synthese und Kristallstrukturen von [BBr2(NPMe3)]2, [B2Br3(NPiPr3)2]Br, [B2(NPEt3)4]Br2, [B2Br2(NPPh3)3]BBr4 und [{B2(NMe2)2}2(NPEt3)2]Cl2 |
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| Authors: | M. M hlen,B. Neumü ller,N. Faza,C. Mü ller,W. Massa,K. Dehnicke |
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| Affiliation: | M. Möhlen,B. Neumüller,N. Faza,C. Müller,W. Massa,K. Dehnicke |
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| Abstract: | Phosphoraneiminato Complexes of Boron. Syntheses and Crystal Structures of [BBr2(NPMe3)]2, [B2Br3(NPiPr3)2]Br, [B2(NPEt3)4]Br2, [B2Br2(NPPh3)3]BBr4 and [{B2(NMe2)2}2(NPEt3)2]Cl The bromoderivatives of the title compounds are prepared from the corresponding silylated phosphoraneimines Me3SiNPR3 and boron tribromide. The boron subcompound [{B2(NMe2)2}2(NPEt3)2]Cl2 derives from Me3SiNPEt3 and B2Cl2(NMe2)2. All complexes are characterized by NMR and IR spectroscopy as well as by crystal structure determinations. [BBr2(NPMe3)]2 (1): Space group P21/n, Z = 2, R = 0.031. Lattice dimensions at ?50°C: a = 723.8, b = 894.2, c = 1305.4 pm, β = 92.35°. 1 forms centrosymmetric molecules in which the boron atoms are linked via μ2-N bridges of the NPMe3? groups of from B2N2 four-membered rings with B? N distances of 149.9 and 150.9 pm. B2Br3(NPiPr3)2]Br (2): Space group P21, Z = 2, R = 0.059. Lattice dimensions at ?80°C: a = 817.6, b = 2198.7, c = 851.5 pm, β = 115.09°. In the cations of 2 the boron atoms are lined via the μ2-N atoms of the NPiPr3? groups to form planar, asymmetric B2N2 four-membered rings with B? N distances of 143 and 156 pm. [B2(NPEt3)4[Br2·4CH2Cl2 (3): Space group C2/c, Z = 4, R = 0.042. Lattice dimensions at ?50°C: a = 1946.1, b = 1180.3, c = 2311.3 pm, β = 101.02°. The structure contains centrosymmetric dications in which both the boron atoms are lined by the N atoms of two of the NPEt3? groups to form a B2N2 four-membered ring with B? N distances of 149.6 pm. The remaining two NPEt3? groups are terminally bonded with very short B? N distances of 133.5 pm. B2Br2(NPPh3)3]BBr4 (4): Space group P1 , Z = 2, R = 0.065. Lattice dimension at ?50°C: a = 1025.7, b = 1496.1, c = 1807.0 pm, α = 85.09°, β = 82.90°, γ = 82.72°. In the cation the boron atoms are lined via the μ2-N atoms of two of the NPPh3? groups to form a nearly planer B2N2 four-membered ring with B? N distances of 149.3-153.1 pm. The third NPPh33 group is terminally connected with teh sp2 hybridized boron atom and with a B? N distance of 134.1 pm along with an almost linear BNP bond angle of 173.6°. [{B2(NMe2)2}2(NPEt2)2]Cl2 · 3CH2Cl2 (5): Space group C2/c, Z = 4, R = 0.098. Lattice dimensions at ?70°C: a = 1557.9, b = 1294.7, c = 2122.9 pm, β = 96.08°. The structure of 4 contains centrosymmetric dications in which two by two B-B dumb-bells are linked via the μ2-N atoms of the two NEPt3? groups to form B4N2 six-membered rings with B? N distances of 150 and 156 pm and B-B distances of 173 pm. The B? N distances of the terminally bonded NMe2? groups correspond to 138 pm double bonds. |
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| Keywords: | Phosphoraneiminato Complexes Boron Compounds Crystal Structures |
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