Jesse W. Taylor

The synthesis and characterization of two new 19-vertex metallaborane clusters: [B18H20Ni(η5- C5H5)]-1 and [B18H19(2-THF)Ni(η5- C5H5)]

Abstract Two new 19-vertex metallaboranes, [B18H20Ni(η5-C5H5)][N(CH3)4] and [B18H19(2-THF)Ni(η5-C5H5)], were isolated from the reaction of anti-B18H22 with nickelocene, [Ni(η5-C5H5)2], in high yields. The complexes were characterized by multinuclear NMR (1H, 13C, 11B), IR and UV–vis spectroscopy. Single-crystal X-ray diffraction analyses of these new complexes confirmed their structures as 19-vertex conjuncto-metallaborane clusters.

Synthesis and characterization of cyano-substituted carborane-based compounds. Molecular structure of [1-(4-C7H7)-12-(C5H3-3-(CN)-3,4-(CH3)2)-C2B10H10]

The reaction of cyanogen chloride with [1-(4-C(7)H(7))-12-(C(5)H(3)-3,4-(CH(3))(2))-C(2)B(10)H(10)] (7) was found to yield two new C(5)-substituted carborane cluster-based compounds, [1-(4-C(7)H(7))-12-(C(5)H(2)-3-(CN)-3,4-(CH(3))(2))-C(2)B(10)H(10)] (8) and [1-(4-C(7)H(7))-12-(C(5)H-2,4-(CN)(2)-3,4-(CH(3))(2))-C(2)B(10)H(10)] (9). This cyano-substitution pattern is in contrast to the known substitution for the analogous organic quinarene[5.6.7] system. The observed unique cluster-based products may be understood by a combination of steric and electronic effects. Compounds 8 and 9 were characterized by complete multinuclear NMR, (1)H-(1)H COSY NMR, (1)H-(13)C HMQC NMR, FTIR, UV-Vis, IR, MS data and a single crystal analysis for 8 [X-ray data for 8: C(17)H(25)B(10)N, monoclinic, space group P2(1)/n with cell constants a = 8.6794(17) Å, b = 11.021(2) Å, c = 43.175(9) Å, β = 91.00(3)°, V = 4129.2(14) Å(3), Z = 8, R(1) = 0.0729, wR(2) = 0.1464].

Formation of new nickel-containing nineteen-vertex metallaborane clusters prepared from the anti-B18H22 borane cluster: molecular structures of [Ni(THF)4(H2O)2][B18H20Ni(η5-C5H5)]2 and [B18H19(2-THF)Ni(η5-C5H5)]

The reaction of the anti-B18H22 borane cluster with nickelocene produced several new metallaborane species, [Ni(THF)4(H2O)2][B18H20Ni(η5-C5H5)]2 (1a), [B18H20Ni(η5-C5H5)] (1b) and [N(CH3)4][B18H19(2-THF)Ni(η5-C5H5)] (2), in relatively high yields. These new complexes were fully characterized by multinuclear NMR (1H, 13C, 11B), IR and UV-Vis spectroscopy. Single-crystal X-ray diffraction analyses of complexes 1a and 2 confirmed their structures as 19-vertex conjuncto-metallaborane clusters. The structures consist of ten-vertex nido-borane subunits edge-shared with eleven-vertex nido-cluster subunits. In compound 2, formed through the THF reflux of compound 1, a THF molecule was found to coordinate at the 2-position of the borane framework.