(1RS,3RS,4RS,10SR)-2,2,3,10-Tetrabromo-1,2,3,4-tetrahydro-1,4-ethanonaphthalene, C12H10Br4, (I), is the first structure to be reported with four Br atoms bound to a 1,4-ethanonaphthalene framework and also the first which possesses three Br atoms inexopositions. Interactions between the Br atoms [three short intramolecular Br...Br distances of 3.1094 (4), 3.2669 (4) and 3.4415 (5) Å] have little effect on the C—C bond lengths but lead to significant twisting of the cage structure compared with the parent hydrocarbon, which is expected to be fully eclipsed at the two saturated C2H4bridge positions. Chemically related (1SR,4RS)-2,3-dibromo-1,4-ethenonaphthalene, C12H8Br2, (II), obtained by double dehydrobromination of (I), represents the first structure of any halogen-substituted benzobarrelene. Thiscis-dibromide shows little evidence of steric congestion at the double bond [Br...Br = 3.5276 (8) Å] as a consequence of the large C—C—Br angles [average C=C—Br angle = 126.15 (10)°].
(1RS,3RS,4RS,10SR)-2,2,3,10-四
溴-1,2,3,4-四氢-1,4-四氢
萘,
C12H10Br4,(I),是第一个报道的在 1,4-ethanonaphthalene 框架中结合有四个 Br 原子的结构,也是第一个具有三个不在位 Br 原子的结构。Br 原子间的相互作用(分子内 Br...Br 间距分别为 3.1094 (4)、3.2669 (4) 和 3.4415 (5)埃)对 C-C 键长度的影响很小,但与母体碳氢化合物相比,却导致笼状结构发生明显扭曲,预计这将使两个饱和
C2H4 桥位置完全黯然失色。与(1SR,4RS)-2,3-二
溴-1,4-乙henonaphthalene(
C12H8Br2,(II))有
化学关系,由(I)的双脱氢
溴化得到,代表了卤素取代的苯并
芘的第一个结构。由于 C-C-Br 角较大[平均 C=C-Br 角 = 126.15 (10)°],这种顺式二
溴化物几乎没有显示出双键处的立体拥塞[Br...Br = 3.5276 (8) Å]。