Positioning of transition metal centres at the upper rim of cone-shaped calix[4]arenes. Filling the basket with an organometallic ruthenium unit
作者:Manuel Lejeune、Catherine Jeunesse、Dominique Matt、Nathalie Kyritsakas、Richard Welter、Jean-Pierre Kintzinger
DOI:10.1039/b110884k
日期:2002.4.9
A series of calix[4]arenes bearing diphenylphosphino groups tethered at the upper rim have been prepared by treatment of 5,11,17,23-tetrabromo-25,26,27,28-tetrapropoxycalix[4]arene with ButLi (or BunLi) followed by reaction with PPh2Cl. The tetraphosphinated derivative 3 was found suitable for the formation of tetranuclear species, notably [3·(AuCl)4], [3·RuCl2(p-cymene)}4], and [3·PdCl(o-C6H4CH2NMe2)}4], all possessing an apparent C4v-symmetry in solution. Reaction of [RuCl2(p-cymene)]2 with the diphosphines 5,17-di-X-11,23-bis(diphenylphosphino)-25,26,27,28-tetrapropoxycalix[4]arene
(X = H, 1; X = Br, 4) afforded the C2v-symmetrical dinuclear complexes [1·RuCl2(p-cymene)}2] and [4·RuCl2(p-cymene)}2], respectively. Reaction of the non-brominated diphosphine 1 with [PdCl(o-C6H4CH2NMe2)]2 gave the complex [1·PdCl(o-C6H4CH2NMe2)}2]. Reaction at high dilution of [PtCl2(1,5-cyclooctadiene)] with 4 or 1 resulted in quantitative formation of the corresponding cis-chelate
complexes [4·PtCl2] (12) and [1·PtCl2] (13), respectively. The trans version of 13 could also be obtained, provided that [PtCl2(PhCN)2] was used as starting complex. In the solid state, the PtCl2 unit of 12 is directed towards one bromine atom, resulting in a highly unsymmetrical calixarene structure where the metal plane is nearly parallel to the calix reference plane. The NMR spectra of 12 and 13 show an apparent C2v-symmetrical structure, suggesting a fast fan-like motion in solution of the metal plane about the P⋯P axis. Similar dynamics are likely
to occur in the related cationic complexes [1·Rh(norbornadiene)]BF4 (15) and [1·Pd(Me-allyl)]BF4 (16). As shown by variable temperature studies carried out on 12 and 16, these dynamics couple with a concomitant, restricted rotation of the two PPh2 units about their coordination axis. The latter motion is probably a result of steric interactions within the phosphorus environment, two PPh rings being in competition for occupation of the cavity entrance. Reaction of the expanded cavity 5,11,17-tribromo-23-diphenylphosphino-25,26,27,28-tetrapropoxycalix[4]arene 5 with [RuCl2(p-cymene)]2 afforded the monophosphine complex [5·RuCl2(p-cymene)]. In solution as well in the solid state, the p-cymene ligand fills the calixarene basket.
通过用 ButLi(或 BunLi)处理 5,11,17,23-四溴-25,26,27,28-四丙氧基杯[4]芳烃,制备了一系列在上缘带有二苯基膦基团的杯[4]芳烃。 ),然后与 PPh2Cl 反应。发现四膦化衍生物 3 适合形成四核物质,特别是 [3·(AuCl)4]、[3·RuCl2(p-cymene)}4] 和 [3·PdCl(o-C6H4CH2NMe2)} 4],在溶液中均具有明显的 C4v 对称性。 [RuCl2(p-伞花烯)]2 与二膦 5,17-二-X-11,23-双(二苯基膦)-25,26,27,28-四丙氧基杯[4]芳烃的反应
(X = H, 1; X = Br, 4) 分别得到C2v对称双核配合物[1·RuCl2(对伞花烃)}2]和[4·RuCl2(对伞花烃)}2]。非溴化二膦1与[PdCl(o-C6H4CH2NMe2)]2反应得到络合物[1·PdCl(o-C6H4CH2NMe2)}2]。高稀释度的 [PtCl2(1,5-环辛二烯)] 与 4 或 1 发生反应,定量形成相应的顺式螯合物
分别为配合物[4·PtCl2] (12) 和[1·PtCl2] (13)。如果使用[PtCl2(PhCN)2]作为起始复合物,也可以获得13的反式版本。在固态下,12 的 PtCl2 单元指向一个溴原子,形成高度不对称的杯芳烃结构,其中金属平面几乎平行于杯参考平面。 12 和 13 的 NMR 谱显示出明显的 C2v 对称结构,表明金属平面溶液中围绕 P⋯P 轴的快速扇形运动。类似的动态也可能发生
发生在相关的阳离子配合物 [1·Rh(降冰片二烯)]BF4 (15) 和 [1·Pd(Me-烯丙基)]BF4 (16) 中。正如对 12 和 16 进行的变温研究所示,这些动力学与两个 PPh2 单元绕其协调轴的伴随的、受限的旋转耦合。后一种运动可能是磷环境内空间相互作用的结果,两个 PPh 环竞争占据空腔入口。膨胀空腔 5,11,17-三溴-23-二苯基膦-25,26,27,28-四丙氧基杯[4]芳烃 5 与 [RuCl2(对伞花烃)]2 反应得到单膦配合物 [5·RuCl2(对伞花烃)]。在溶液中以及在固态中,对伞花烯配体填充杯芳烃篮。