立体化学刚性的七配位环戊二烯基三(二苄基二硫代氨基甲酸)钛、锆、铪配合物的合成和性质

二烷基二硫代氨基甲酸基作为良好的双齿配体较易与过渡金属生成高配位的配合物,含有环戊二烯基的高配位钛、锆、铪配合物的研究相继出现^[1-5],这类七配位、18-电子构型的配合物是立体化学刚性,具有独特的光谱性质和结构行为。选择钛、锆和铪二茂二氯化物与三当量的二苄基二硫代氨基甲酸钠反应合成了五种未见报道的七配位配合物,讨论了产物的光谱性质和配位结构。     

手性在锆原子上的二茂锆配合物的合成

由新孟基环戊二烯和三甲基硅基环戊二烯制备了两个前手性的二茂锆配合物。由它们与亲核试剂的反应,合成了一些新的,手性在锆原子上的锆配合物。^1HNMR和^1^3CNMR谱图表明,配体上的手性基团对锆原子上的取代反应有明显的手性诱导效果。     

新型氮杂大环化合物的研究3: 取代不对称多齿氮 杂大环化合物的合成、表征 与配位性能

合成了四种以Nsp^2和Nsp^3为配位原子的取代不对称多齿氮杂大环化合物,制备了它们与不同金属离子的配合物,通过元素分析和光谱表征,研究了配体的结构与其配位性能的关系。以吡啶环为侧链功能基的配体L^1和L^2可根据其环大小选择性地识别Na^+或K^+离子,与过渡金属离子形成1:1型配合物,而与Hg^2^+,Cd^2^+等离子则形成1:2型配合物。大环配体L^3与Co^2^+和Na^+离子形成的双核配合物中两个冠醚环和一个Na^+离子形成夹心配位结构。L^5环中有两个配位中心,因而可同时与两个Ru^2^+离子配位。L^1和L^2均表现出对不同金属离子良好的液膜传输性能和传输选择性。     

新型氮杂大环化合物的研究3: 取代不对称多齿氮 杂大环化合物的合成、表征 与配位性能

合成了四种以Nsp^2和Nsp^3为配位原子的取代不对称多齿氮杂大环化合物,制备了它们与不同金属离子的配合物,通过元素分析和光谱表征,研究了配体的结构与其配位性能的关系。以吡啶环为侧链功能基的配体L^1和L^2可根据其环大小选择性地识别Na^+或K^+离子,与过渡金属离子形成1:1型配合物,而与Hg^2^+,Cd^2^+等离子则形成1:2型配合物。大环配体L^3与Co^2^+和Na^+离子形成的双核配合物中两个冠醚环和一个Na^+离子形成夹心配位结构。L^5环中有两个配位中心,因而可同时与两个Ru^2^+离子配位。L^1和L^2均表现出对不同金属离子良好的液膜传输性能和传输选择性。     

柄型金属有机化合物（Ⅴ）——锗桥连茚基及取代茚基锆合物的合成及催化烯烃聚合

锗桥连茚及取代茚配体相继与丁基锂及ZrCl4作用，生成锗桥连茚基及取代茚基锆化合物Me2Ge(2-R^1-4-R^2-Ind)2ZrCl2[R^1=R^2=H(1);R^1=Me,R^2=H(2);R^1=Me,R^2=Ph(3)]。化合物1－3均为内消旋和外消旋异异构体的混合物，通过多次重结晶得到化合物1和2的纯外消旋异构体及化合物3的内消旋异构体。由元素分析和^1H NMR谱表征了化合物的分子结构。研究了在甲基铝氧烷（MAO）的助催化下，化合物1－3对乙烯和丙烯聚合的催化性能。由锗桥连茚基化合物1－3得到的聚乙烯的分子量分布比一般茂金属催化剂略宽，内消旋和外消旋异构体的混合物（3）由于两个催化活性中心不等同而使得到的聚乙烯的分子量分布相当宽。外消旋异构体1和2催化丙烯聚合得到高等规聚丙烯。     

水相法合成水杨酸类二茂钛衍生物与取代基效应及酸度影响的研 究

用二氯二茂钛-乙酰丙酮的水溶液与取代水杨酸钠在不同pH条件下合成了两种类型的配合物。所有配合物经元素分析、IR和^1HNMR进行了结构表征,并通过Hammett方程,描述了取代基效应与二茂钛水杨酸类配合物的合成和性质之间的联系。结果表明:Hammettσ值对反应有较大影响,取代基的σ值越大,越有利于合成产物由A型向B型配合物过渡;产物的颜色、分解温度、IR及^1HNMR亦与取代基有一定关系。     

茚环3-位手性基团取代的桥联二茚锆络合物合成及表征

将(+)-新孟基和(+)-异莰基引入茚环结构中,合成得到三个茚环3-位手性基团取代的桥联二茚配体化合物1a~3a.利用这些配体化合物的二锂盐与四氯化锆反应,最终分离得到两个C2-对称的亚乙基桥联取代二茚锆络合物2b和3b,相应具类内消旋结构、C1-对称的锆络合物2c和3c未能分离得到纯品.所有配体化合物和络合物均通过1H NMR、13C NMR、元素分析(或HRMS)的鉴定.对络合物2c进一步用X射线单晶衍射测定了晶体结构.2c属正交晶系,其空间群为P2(1)2(1)2(1),晶胞参数a=10.946(4),b=13.377(4),c=24.294(8),α=β=γ=90°,Mr=694.94,V=3557(2)3,Dc=1.298 g/cm3,Z=4,F(000)=1464,μ=0.486 mm-1,R=0.0296,wR=0.0683[I2σ(I)].     

水相法合成双(环戊二烯基)钛氨基酸配合物的研究

以N-(取代苯基)氨基乙酸及盐与双(环戊二烯基)二氯化钛在水相及有机相反应,得到了五个双(环戊二烯基)钛氨基酸配合物,对配合物进行了熔点、元素分析、IR及^1HNMR的表征,确定了它们的结构。这些配合物在空气中稳定。经比较,水相中的合成反应速度快,操作简便,产物较易分离,产率高。     

二甲基硅桥联双茚基二氯化锆烯烃聚合均相催化剂合成方法的改进

二甲基硅桥联双茚基二氯化锆烯烃聚合均相催化剂合成方法的改进苏立明，周松，贺大为（中国科学院化学研究所，北京１０００８０）自从８０年代初出现Ｂｒｉｎｔｚｉｎｇｅｒ型桥联的第四过渡金属族茂基化合物［１］及Ｋａｍｉｎｓｋｙ发现甲基铝氧烷（ＭＡＯ）与金属茂化...     

含分子内配位键的(MeOCH~2CH~2C~5H~4)~2UCl~2的合成及表征

四氯化铀与 二当量甲氧乙基环戊二烯基钠在THF中于60℃反应, 合成得到新的二(甲氧乙基环戊二烯基)二氯化铀配合物. 产物经红外光谱, ^1H NMR和质谱鉴定 .     

Complexes of manganese, iron and cobalt with sterically demanding indenyl ligands

A series of manganese, iron and cobalt complexes bearing sterically demanding 1,3-disubstituted indenyl ligands, 1,3-(Me(3)C)(2)C(9)H(5) (Ind(tBu)) (1) and 1,3-(C(6)H(11))(2)C(9)H(5) (Ind(cHexyl)) (2), has been prepared. These complexes have been fully characterised by various spectroscopic techniques, elemental analysis, and X-ray diffraction experiments. In addition the electronic and steric properties of these ligands have been evaluated. Although the cone angles and electronic properties are similar to 1,2,4-(Me(3)C)(3)C(5)H(2) (Cp'), indenyl iron half-sandwich complexes are only stable at low temperature. This has been demonstrated for 1-FeI using suitable trapping experiments such as CO or NaCp' addition to yield 1-Fe(CO)(2)I and 1-FeCp', respectively. Overall the metal-ligand bonds in these indenyl compounds are weaker than in the corresponding cyclopentadienyl derivatives. In addition, the bis(indenyl)manganese complexes, 1-Mn and 2-Mn, are high-spin, as established by solid state magnetic susceptibility studies in the temperature range 2-300 K.     

Organometallic conformational equilbria : XVI. Steric effects on π-allyl and π-indenyl orientation in molybdenum and tungsten complexes

Steric effects on π-allyl and π-indenyl orientation in molybdenum and tungsten complexes have been studied. Magnetic anistropies associated with indenyl derivatives have provided a definitive technique for determination of stereochemistry in these complexes. The steric factors which determine the stability of the orientations of the allyl moiety have been discussed. Generally π-cycloentadienyl or π-indenyl ligands have been considered to be essentially freely rotating. Analysis of the magnitude of the magnetic anisotropy arising from the benzene ring has suggested that there is relatively free rotation of the indenyl ligands, but there is a preferred conformation with the six-membered ring oriented over the allyl. Appropriate substitution on the allyl offers sufficient steric hindrance to make other conformations more probable.     

Importance of planar chirality in chiral catalysts with three chiral elements: the role of planar chirality in 2'-substituted 1,1'-P,N-ferrocene ligands on the enantioselectivity in Pd-catalyzed allylic substitution.

A series of novel planar chiral 2'-substituted 1,1'-P,N-ferrocene ligands 9-11, 14, and 16 were prepared with diastereopurity >99:1 and found to be effective in asymmetric allylic alkylation and amination reactions. Ligand 14 furnished the highest enantiomeric excess, 98.5% and 96.5% ee in alkylation and amination reactions, respectively. The role of planar chirality in asymmetric reactions has been examined, and decisive effects on enantioselectivity as well as the control of absolute configuration in palladium-catalyzed allylic alkylation and amination reactions were observed. To clarify why and how the planar chirality governed the stereochemical outcome, X-ray crystallographic structures of eta(3)-diphenylallyl Pd complexes, (1)H NMR, (31)P NMR spectra of palladium dichloride complexes, and eta(3)-diphenylallyl Pd complexes of three 1,1'-P,N-ferrocene ligands were analyzed with the aid of COSY and 2D NOESY experiments. All results led to the conclusion that planar chirality influences the stereochemical outcome by changing or even inverting the ratio of two rotamers because of the steric interaction between a planar chiral group and the coordination site.     

Spin-state alteration from sterically enforced ligand rotation in bis(indenyl)chromium(II) complexes

The rotational orientation of cyclopentadienyl rings usually has no effect on d-orbital energy levels and splitting in transition metal complexes. With related but less symmetrical carbocyclic ligands, however, the magnetic properties of the associated complexes can be altered by the alignment of the ligands. Examples of this effect are found in substituted organochromium(II) bis(indenyl) complexes. The monosubstituted compounds (1-RC(9)H(6))(2)Cr (R = t-Bu, SiMe(3)) are prepared from the substituted lithium indenides and CrCl(2) in THF; they are high-spin species with four unpaired electrons. Their spin state likely reflects that in the unknown monomeric (C(9)H(7))(2)Cr, which is calculated to have a high-spin (S = 2) ground state in the staggered configuration (180 degrees rotation angle). However, the analogous bis(indenyl) complexes containing t-Bu or SiMe(3) groups in both the 1 and 3 positions on the indenyl ligands ((1,3-R(2)C(9)H(5))(2)Cr) are low-spin compounds with two unpaired electrons. X-ray diffraction results indicate that [1-(t-Bu)C(9)H(6)](2)Cr exists in a staggered conformation, with Cr-C (av) = 2.32(4) A. In contrast, the average Cr-C distances in [1,3-(t-Bu or SiMe(3))(2)C(9)H(5)](2)Cr are 2.22(2) and 2.20(2) A, respectively, and the rings are in a gauche configuration, with rotation angles of 87 degrees. The indenyl conformations are sterically imposed by the bulk of the t-Bu and SiMe(3) substituents. The change from a staggered to a gauche indenyl orientation lowers the symmetry of a (C(9)H(7))(2)M complex and allows greater mixing of metal and ligand orbitals. Calculations indicate that previously nonbonding pi orbitals of the indenyl anion are able to interact with the chromium d orbitals, producing bonding and antibonding combinations. The latter remain unpopulated, and the resulting increase in the HOMO-LUMO gap forces the complexes to adopt a low-spin configuration. The possibility of using sterically imposed ligand rotation as a means of spin-state manipulation makes indenyl compounds a potentially rich source of magnetically adjustable molecules.     

柄型金属有机化合物(V)——锗桥连茚基及取代茚基锆化合物的合成及催化烯烃聚合

锗桥连茚及取代茚配体相继与丁基锂及ＺｒＣｌ４作用,生成锗桥连茚基及取代茚基锆化合物Ｍｅ２Ｇｅ(２－Ｒ１－４－Ｒ２－Ｉｎｄ)２ＺｒＣｌ２[Ｒ１＝Ｒ２＝Ｈ(１);Ｒ１＝Ｍｅ,Ｒ２＝Ｈ(２);Ｒ１＝Ｍｅ,Ｒ２＝Ｐｈ(３)]．化合物１－３均为内消旋和外消旋异构体的混合物,通过多次重结晶得到化合物１和２的纯外消旋异构体及化合物３的内消旋异构体．由元素分析和１Ｈ ＮＭＲ谱表征了化合物的分子结构．研究了在甲基铝氧烷(ＭＡＯ)的助催化下,化合物１－３对乙烯和丙烯聚合的催化性能．由锗桥连茚基化合物１－３得到的聚乙烯的分子量分布比一般茂金属催化剂略宽．内消旋和外消旋异构体的混合物(３)由于两个催化活性中心不等同而使得到的聚乙烯的分子量分布相当宽．外消旋异构体１和２催化丙烯聚合得到高等规聚丙烯．     

How big is a Cp? Cycloheptatrienyl zirconium complexes with bulky cyclopentadienyl and indenyl ligands

A combination of phase-transfer and traditional alkylation strategies has been employed to synthesise sterically encumbered 1,3-di(cyclohexyl) and 1,3-di(tert-butyl) substituted indenes in multi-gram quantities. These indenyl ligands and sterically demanding alkyl cyclopentadienyl ligands have been used to prepare a series of [(η(7)-C(7)H(7))Zr(η(5)-L)] (L = Cp and Ind) complexes by straightforward salt metathesis between [(η(7)-C(7)H(7))ZrCl(tmeda)] and the corresponding sodium indenide or cyclopentadienide. All of these Zr complexes have been characterized by elemental analysis, NMR spectroscopy and single crystal X-ray diffraction. The structural information derived from these studies was employed to evaluate the steric demand of these ligands in a realistic manner.     

3,3,7,7,9-五甲基-1,5-二氧螺[5.5]十一烷-8-酮的核磁共振研究

以1,3-环己二酮为起始原料,经过3步合成,得到了适用于多种天然产物合成中的关键中间体3,3,7,7,9-五甲基-1,5-二氧螺[5.5]十一烷-8-酮。利用红外光谱、元素分析以及1H与13CNMR确定了目标化合物的准确结构;利用二维核磁共振技术1H-1HCOSY、NOESY、HMBC以及HSQC,对其1H和13CNMR进行了全归属,并得到了目标化合物的空间结构相关信息。     

Structure, stability, and interconversion barriers of the rotamers of cis-[Pt(II)Cl(2)(quinoline)2] and cis-[Pt(II)Cl(2)(3-bromoquinoline)(quinoline)] from X-ray crystallography, NMR spectroscopy and molecular mechanics evidence

Reported are the preparations of cis-[PtCl(2)(quinoline)(2)] and cis-[PtCl(2)(3-bromoquinoline)(quinoline)] and an investigation of the stabilities and interconversion of the rotamer forms of these complexes. Both head-to-head (HTH) and head-to-tail (HTT) rotamer forms are found in the crystal structure of cis-[PtCl(2)(quinoline)(2)]. The NOESY NMR spectrum of cis-[PtCl(2)(quinoline)(2)] in dmf-d(7) at 300 K is consistent with conformational exchange brought about by rotation about the Pt-N(quinoline) bonds. H.H nonbonded distances between H atoms of the two different quinoline ligands were determined from NOESY data, and these distances are in accord with those observed in the crystal structure and derived from molecular mechanics models. cis-[PtCl(2)(3-bromoquinoline)(quinoline)] was prepared to alleviate the symmetry-imposed absence of inter-ring H2/H2 and H8/H8 NOESY cross-peaks for cis-[PtCl(2)(quinoline)(2)]. Molecular mechanics calculations on the complexes show the HTT rotamers to be 1-2 kJ mol(-)(1) more stable than the HTH forms, consistent with the (1)H spectra where the intensities of resonances for the two forms are approximately equal. Variable-temperature (1)H NMR spectra of cis-[PtCl(2)(quinoline)(2)] in dmf-d(7) indicate a rotational energy barrier of 82 +/- 4 kJ mol(-)(1). Variable-temperature (1)H NMR spectra indicate that the Br substituent on the quinoline ring does not affect the energy barrier to interconversion between the HTT and HTH forms (79 +/- 5 kJ mol(-)(1)). The steric contribution to the rotation barrier was calculated using molecular mechanics calculations and was found to be approximately 40 kJ mol(-)(1), pointing to a possible need for an electronic component to be included in future models.     

Structure elucidation of the unprecedented asymmetric bis-chelate complex [Pd(1,3-bis(di(o-methoxy-m-methylphenyl)phosphino)propane)2]2+ in the solid state and in solution

Complexes of the type [Pd(ligand)(2)](anion)(2) were prepared with a series of bidentate di(o-methoxyphenyl)phosphine ligands with increasing steric bulk on the meta position of the phenyl groups: m-H (L1); m-MeO (L2); and m-Me (L3). The solid-state structure of [Pd(L2)(2)](OTs)(2) revealed that the two ligands are symmetrically coordinated to Pd(2+). In the solid state structure of [Pd(L3)(2)](OTs)(2) however, the two ligands are unsymmetrically coordinated to Pd(2+), yielding an unprecedented conformation of this bis-chelate P(4)Pd(2+) complex. (1)H-(1)H-COSY and NOESY analysis and a (31)P-NMR simulation showed that the asymmetric structure of [Pd(L3)(2)](OTs)(2) is retained in solution.     

The nature of the indenyl effect

The eta(5)-to-eta(3) coordination shift of cyclopentadienyl (Cp=C(5)H(5)(-)) and indenyl (Ind=C(9)H(7)(-)) ligands in molybdenocene complexes, [(eta(5)-Cp')(eta(5)-Cp)Mo(CO)(2)](2+) (Cp'=Cp or Ind), driven by a two-electron reduction of those species, was studied and compared by means of molecular orbital calculations (B3LYP HF/DFT hybrid functional, DZP basis sets). The results obtained, in terms of optimized geometries, relative energies, and bond analysis parameters, compare well with the experimental data, and verify the well-known indenyl effect, that is, a significantly more facile eta(5)-to-eta(3) rearrangement for the indenyl ligand when compared to cyclopentadienyl. However, the study of the folding of free Cp and Ind, combined with the (eta(5/3)-Cp')-M bond analysis, shows that the observed difference is not the result of an intrinsic characteristic of the indenyl ligand, such as the traditionally accepted aromaticity gain in the benzene ring formed in eta(3)-Ind complexes. Instead, it is directly related to the Cp'-M bond strength. While the difference in the energy required to fold the two free ligands is negligible (< or =1 kcal mol(-1) for folding angles up to 20 degrees), the (eta(5)-Cp)-M bond is stronger than that of (eta(5)-Ind)-M; however, the opposite situation is found for the eta(3) coordination mode. The net result, for Cp'=Ind, is a destabilization of the eta(5) complexes and a stabilization of the eta(3) intermediates or transition states yielding smaller activation energies and faster reaction rates for processes in which that is the rate-determining step.