Synthesis and complexation of multiarmed cycloveratrylene-type ligands: observation of the "boat" and "distorted-cup" conformations of a cyclotetraveratrylene derivative.
Synthesis and complexation of multiarmed cycloveratrylene-type ligands: observation of the "boat" and "distorted-cup" conformations of a cyclotetraveratrylene derivative.
复制标题
多臂环四乙烯型配体的合成和络合：环四乙烯衍生物的“船”和“扭曲杯”构象的观察。
作者：
C. Sumby;K. Gordon;T. Walsh;M. Hardie
研究了一个先前报道的配体，六（2-吡啶基甲基）环三儿茶烯（1），和一个新的四聚体桥连配体，八（2-吡啶基甲基）环四儿茶烯（2），后者构建在一个更大的环四藜芦烯（CTTV）支架上，进行了描述。变温NMR研究支持2的“沙发”构象，类似于对母体化合物的研究。2及其较小的三聚体同系物的配位化学也已被研究与银（I），铜（II）和钯（II）的盐。在DMF子集[Pd（3）Cl（6）（1）] x DMF的结构中观察到1的意外螯合模式，其中钯阳离子桥接两个藜芦醇亚基而不是在单个亚基内螯合。在[Ag（4）（2）][Co（C（2）B（9）H（11））（2）]（4）× 2.8 CH（3）CN × H（2）O中，配体2采用“船”构象，而在[Pd（4）Cl（8）（2）] × 4 H（2）O中，（1）H NMR光谱研究和计算表明配体2以以前未观察到的“扭曲杯”构象存在。这种构象的能量比另一种“沙发”构象低约90 kJ mol（-1）。因此，协调诱导的构象控制CTTV衍生物提供了新的途径，利用这些化合物的主客体化学。
Investigations of a previously reported ligand, hexakis(2-pyridylmethyl)cyclotricatechylene (1), and a new tetrameric bridging ligand, octakis(2-pyridylmethyl)cyclotetracatechylene (2), the latter constructed on a larger cyclotetraveratrylene (CTTV) scaffold, are described. Variable-temperature NMR studies support a "sofa" conformation for 2, akin to studies on the parent compound. The coordination chemistry of 2 and its smaller trimeric homologue have also been investigated with silver(I), copper(II) and palladium(II) salts. An unexpected chelating mode was observed for 1 in the structure of DMF subset[Pd(3)Cl(6)(1)] x DMF, whereby the palladium cations bridge two veratrole subunits rather than chelating within a single subunit. In the structure of [Ag(4)(2)][Co(C(2)B(9)H(11))(2)](4) x 2.8 CH(3)CN x H(2)O, ligand 2 adopts a "boat" conformation, whereas in [Pd(4)Cl(8)(2)] x 4 H(2)O, (1)H NMR spectroscopic studies and calculations indicate that the ligand is present in a previously unobserved "distorted-cup" conformation. This conformation was calculated to be approximately 90 kJ mol(-1) lower in energy than the alternative "sofa" conformation. Thus, coordination-induced conformational control over CTTV derivatives offers new routes to exploit the host-guest chemistry of these compounds.
DOI：
10.1107/s0108767394005726
发表时间：
1995-01-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION A
影响因子：
--
作者：
BLESSING, RH
通讯作者：
BLESSING, RH