Five-coordinate titanium(IV) complexes. Infrared spectral studies on X3Ti(diketonato) and XY2Ti(diketonato) complexes and the crystal and molecular structure of di-.mu.-chloro-tetrachlorobis(2,4-pentanedionato)dititanium(IV)
Five-coordinate titanium(IV) complexes. Infrared spectral studies on X3Ti(diketonato) and XY2Ti(diketonato) complexes and the crystal and molecular structure of di-.mu.-chloro-tetrachlorobis(2,4-pentanedionato)dititanium(IV)
复制标题
五配位钛(IV)配合物。
DOI：
10.1021/ic50175a045
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发表时间：
1977
影响因子：
4.6
通讯作者：
D. G. Bickley
中科院分区：
文献类型：
--
作者：
N. Serpone;P. Bird;A. Somogyvari;D. G. Bickley
X3Ti (dik) 和 XY2Ti (dik) 类型的一系列表观五配位钛 (IV) 配合物[其中 X= Y 和 X/Y； X= Y= F、Cl 或 Br； dik = 2, 4-戊二酸根阴离子 (acac)、苯甲酰丙酮酸根阴离子 (bzac)、二异丁酰基甲烷酸根阴离子 (dibm) 和二新戊酰基甲烷酸根阴离子 (dpm)] 通过 TiX4 与 Hdik 或与 Ti (dik) 2X2 以等摩尔量反应制备。那些含有溴的物质似乎分解稳定性较差并且对湿气更敏感。报告了 Cl3Ti (acac) 和 FCl2Ti (acac) 的固态 (Nujol) 红外光谱，并与母体六配位 Ti (acac) 2X2 (X= F, Cl) 配合物的光谱进行了比较。 FCl2Ti (acac) 光谱中末端 Ti-F 伸缩频率的缺失表明该物质至少具有二聚结构。上述物质在各种有机溶剂中的低溶解度排除了溶液红外光谱。二-q-氯-四氯双(2, 4-戊二酮)二钛(IV),[Cl3Ti (acac)] 2 的结构已通过使用Mo K< x 辐射(0.71069 Á) 的x 射线单晶衍射方法确定。晶胞数据为空间群 P2\/n（编号 14）、Z= 2、a= 8.381 (5) A、b= 10.734 (5) A、c= 10.517 (6) k、a= 90.00、ß= 93.92 (3)、y= 90.00 和 V= 994.573 A3。使用耦合 6-26 扫描技术收集衍射仪数据，在所有非氢原子的各向异性全矩阵细化和所有氢原子的各向同性全矩阵细化（对甲基氢具有刚体约束）之后，最终未加权和加权 R 值分别为 0.031 和 0.029。根据对称性的要求，该结构是中心对称的，并且由具有通过两个氯桥连接的两个钛（IV）原子的环状二聚体组成。钛的几何形状是扭曲的八面体，相邻供体原子之间的键角在81.77 (4)—97.43 (5)范围内，三个钛供体原子反式键之间的键角在166.50 (9)—173.17 (5)范围内。钛-氯桥距分别为2.418(1)和2.569(1)A；两个钛端氯键长度分别为 2.214 (1) 和 2.250 (1) A。 [Cl3Ti (acac)] 2 中 2.582 (4) A 的 0-0“咬合”距离比其他乙酰丙酮配合物（例如 Zr (acac) 4、2.67 A）中报道的距离短得多。这是合理的，因为负电性氯在钛上产生了更大的有效核电荷，并且支持了 Ti (acac) 平面杂螯合环中显着类型键合的概念。
A series of apparent five-coordinate titanium (IV) complexes of the type X3Ti (dik) and XY2Ti (dik)[where X= Y and X/Y; X= Y= F, Cl, or Br; dik= 2, 4-pentanedionate anion (acac), benzoylacetonate anion (bzac), diisobutyrylmethanate anion (dibm), and dipivaloylmethanate anion (dpm)] have been prepared by reacting TiX4with Hdik or with Ti (dik) 2X2 in equimolar amounts. Those species containing bromine appear to be less stable to decomposition and to be more moisture sensitive. Solid state (Nujol) infrared spectra for Cl3Ti (acac) and FCl2Ti (acac) are reported and compared with those of the parent six-coordinate Ti (acac) 2X2 (X= F, Cl) complexes. Absence of the terminal Ti-F stretching frequency in the spectrum of FCl2Ti (acac) indicates at least a dimeric structure for this species. The low solubilityof the above species in various organic solvents precluded solution infrared spectra. The structure of di-q-chloro-tetrachlorobis (2, 4-pentanedionato) dititanium (IV),[Cl3Ti (acac)] 2, has been determined by x-ray single-crystal diffraction methods using Mo K< x radiation (0.71069 Á). The unit cell data are space group P2\/n (No. 14), Z= 2, a= 8.381 (5) A, b= 10.734 (5) A, c= 10.517 (6) k, a= 90.00, ß= 93.92 (3), y= 90.00, and V= 994.573 A3. Diffractometer data were collected using a coupled 6-26 scan technique and final unweighted and weighted R values after anisotropic full-matrix refinement of all nonhydrogen atoms and isotropic full-matrix refinement of all hydrogen atoms (with rigid body constraints on methyl hydrogens) were 0.031 and 0.029, respectively. The structure is centrosymmetric as required by symmetry and consists of a cyclic dimer with thetwo titanium (IV) atoms linked by two chlorine bridges. The geometry at titanium is a distorted octahedron with bond angles between adjacent donor atoms in the range 81.77 (4)—97.43 (5), and bond angles between the three titanium-donor atom trans bonds in the range 166.50 (9)—173.17 (5). The titanium-chlorine bridgedistances are 2.418 (1) and 2.569 (1) A; the two titanium-terminal chlorine bond lengths are 2.214 (1) and 2.250 (1) A. The 0-0 “bite” distance of 2.582 (4) A in [Cl3Ti (acac)] 2 is considerably shorter than those reported in other acetylacetonate complexes (eg, Zr (acac) 4, 2.67 A). This is rationalized interms of a greater effective nuclear charge at titanium induced by the electronegative chlorines, and supports the notion of significant-type bonding in the Ti (acac) planar heterochelated ring.