Multiple bonds between main-group elements and transition metals. 104. (.sigma.-Aryl)trioxorhenium(VII) complexes: syntheses, structural characterization, and properties
Multiple bonds between main-group elements and transition metals. 104. (.sigma.-Aryl)trioxorhenium(VII) complexes: syntheses, structural characterization, and properties
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主族元素和过渡金属之间存在多重键。
DOI：
10.1021/om00039a012
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发表时间：
1992
期刊：
影响因子：
2.8
通讯作者：
C. Whitaker
中科院分区：
文献类型：
--
作者：
C. Bellefon;W. Herrmann;P. Kiprof;C. Whitaker
N（CH2CH2）3CH）。新的有机锌试剂（Me_3SiO-Xy）ZnCl（THF）（7）（Me_3SiO-Xy =2，6-二甲基-4-（三甲基硅氧基）苯基）与Re_（207）反应，高产率地生成深黄色配合物（Me_3SiO-Xy）Re_（03）（8）。8与HCl反应得到第一个浅黄色羟基苯基配合物（HO-Xy）ReO 3（9）（HO-Xy=2，6-二甲基-4-羟基苯基）。RRe 0 3配合物中Re中心的刘易斯酸性取决于芳基R的电子和空间因素。因此，1不与THE和奎宁环形成加合物，而6仅作为奎宁环加合物可分离。化合物3形成不稳定的THE加合物4和强奎宁环加合物Ph（quin）ReO 3（10）。所有化合物均经IR、~ 1H、~（13）C和~（10）NMR表征。系列1-3和5的1 - 3C NMR数据表明ReO 3基团是强吸电子取代基。配合物1、4和8的结构经X射线单晶衍射表征。配合物1以两种不同的空间群结晶：单斜晶系P2 l/m（1A型）和正交晶系Pnma（IB型），分别来自乙醚和正戊烷。结构1A在晶胞中具有两个不同的分子1A 1和1A 2，其不同之处在于苯基平面与ReO 3片段的相对取向（1A：a= 8.210（1）A，B= 22.924（3）A，c= 8.141（1）A，A = 102.21（1），Z= 6. IB：o= 7.343（2）A，B= 10.166（2）A，c= 13.600（3）A，Z= 4）。配合物4：单斜晶系P2 jc，a= 8.580（1）A，B= 11.562（1）A，c= 12.407（2）A，A = 109.34（7），Z= 4.配合物8：单斜晶系PZi/m，a = 8.245（1）A，B= 7.492（1）A，c= 11.991（2）A，λ = 100.83（< 1），Z-2.分子IB和8为假四面体。相比之下，在4中的双中心有一个扭曲的三角双锥配位几何，与三个氧代配体定义的赤道平面。分子1A 1中的Re-C键长（2.006（9）A）明显短于1A 2（2.063（7）A）、IB（2.075（8）A）和8（2.04（1）A）。4中的不同几何形状对Re-C键长（2.071（3）A）没有影响。3在60-80 ℃的热降解仅产生联苯，表明分子间分解途径。相比之下，1和2在高达200 ℃下是稳定的。这种热稳定性的显著差异可归因于空间位阻的增加，从而避免了分子间偶联分解。
N (CH2CH2) 3CH). The new organozinc reagent (Me3SiO-Xy) ZnCl (THF)(7)(Me3SiO-Xy=2, 6-dimethyl-4-(trimethylsiloxy) phenyl) reacts with Re207 to yield the deep yellow complex (Me3Si0-Xy) Re03 (8) in highyields. Reaction of 8 with HC1 gives the first, pale yellowhydroxyphenyl complex (H0-Xy) Re03 (9)(HO-Xy=2, 6-dimethyl-4-hydroxyphenyl). The Lewis acidityof the Re center in theRRe03 complexes depends on both electronic and steric factors of the aryl group R. Thus, 1 does not form adducts with THE and quinuclidine, whereas 6 is isolable only as a quinuclidine adduct. Compound 3 forms the labile THE adduct 4 and the strong quinuclidine adduct Ph (quin) Re03 (10). All compounds have been characterizedby IR and lH, 13C, and “O NMR spectroscopy. The 13C NMR data for the series 1-3 and 5 indicate that the Re03 group is a strong electron-withdrawing substituent. Complexes 1, 4, and 8 have been characterized by single-crystal X-ray diffraction. Complex 1 crystallizes in two different space groups: monoclinic P2l/m (type 1A) and orthorhombic Pnma (type IB), from diethyl ether and n-pentane, respectively. Structure 1Ahas two different molecules, 1A1 and 1A2, in the unit cell, differing by the relative orientation of the phenyl plane to the Re03 fragment (1A: a= 8.210 (1) Á, b= 22.924 (3) A, c= 8.141 (1) A, ß- 102.21 (1), Z= 6. IB: o= 7.343 (2) A, b= 10.166 (2) A, c= 13.600 (3) A, Z= 4). Complex 4: monoclinic P2jc, a= 8.580 (1) A, b= 11.562 (1) A, c= 12.407 (2) Á, ß= 109.34 (7), Z= 4. Complex 8: monoclinic PZi/m, a- 8.245 (1) A, b= 7.492 (1) A, c= 11.991 (2) A, ß= 100.83 (< 1), Z-2. Molecules, IB, and 8 are pseudotetrahedral. In comparison, the rhenium center in 4 has a distorted trigonal-bipyramidal coordination geometry, with the three oxo ligands defining the equatorial plane. The Re-C bond length is noticeably shorter in molecule 1A1 (2.006 (9) A) than in 1A2 (2.063 (7) A), IB (2.075 (8) A), and 8 (2.04 (1) A). The different geometry in 4 has no influence on the Re-C bond length (2.071 (3) A). Thermal degradation of 3 at 60-80 C gives only biphenyl, indicating an intermolecular decomposition pathway. In comparison, 1 and 2 are stable up to 200 C. This remarkable difference in thermal stability can be attributed to increased steric hindrance, thus avoiding intermolecular coupling decomposition.