Koordinationseigenschaften der isolobalen Phosphaniminatound Cyclopentadienyl‐Liganden in TiCl3(NPH3), TiCl3Cp,ReO3(NPH3) und ReO3Cp

Coordination Behaviour of the Isolobal Phosphoraneiminato and Cyclopentadienyl Ligands in TiCl₃(NPH₃), TiCl₃Cp, ReO₃(NPH₃), and ReO₃Cp The phosphoraneiminato and cyclopentadienyl complexes TiCl₃(NPH₃) ( 1 ), ReO₃(NPH₃) ( 2 ), TiCl₃Cp ( 3 ), and ReO₃Cp ( 4 ) have been investigated quantum chemically at the BP86/TZ(2)P level of nonlocal density functional theory (DFT). The metal–ligand bonds turn out to dissociate homolytically with the computed values for the corresponding bond dissociation energies amounting to 79.6 ( 1 ), 103.4 ( 2 ), 58.1 ( 3 ) and 45.0 ( 4 ) kcal/mol. Whereas the M–N–P unit in the titanium complex 1 is linear, we find a bent structure for the corresponding rhenium complex 2 (∠ Re–N–P = 136.4°). It turns out that the potential energy surface of the phosphoraneiminato complexes is extremely shallow with respect to the M–N–P angle; a variation over 50° is associated with an energy change of less than 2 kcal/mol. Furthermore, we have carried out a detailed analysis of the bonding in our model complexes to elucidate the difference in metal–ligand bond strengths between the isolobal phosphoraneiminato and cyclopentadienyl ligands.     

Preparation,characterization and reactivity of Cp2M(PMe3)2 complexes (M = Ti,Zr): the molecular structure of Cp2Zr(PMe3)2

The reduction of Cp₂MCl₂ (M = Ti, Zr) with magnesium in THF in the presence of PMe₃ affords the complexes Cp₂M(PMe₃)₂ in high yields. These compounds lose one or both PMe₃ ligands under very mild conditions. Cp₂Ti(PMe₃)₂ reacts readily with CH₃I, CH₃C(O)Cl, PhSSPh, Me₂PCH₂CH₂PMe₂, CO, RCN (R = Me, t-Bu) or (RN)₂S (R = t-Bu, Me₃Si) to give the corresponding titanocene products. The structure of Cp₂Zr(PMe₃)₂ has been determined by X-ray diffraction; the structural parameters are similar to those of the titanium analog Cp₂Ti(PMe₃)₂ except that the Zr-P and Zr-C distances are longer.     

ESR Study of the Reaction Between Cp2Ti(CO)2 and Cp2TiBr2

Introduction Floriani and Fachinetti have proposed that (Cp_2TiCl)_2 can be prepared by the reaction between Cp_2TiCl_2 and Cp_2Ti(CO)_2. We extended the method to the preparation of (Cp_2TiBr)_2 and characterized an active intermediate by ESR method.     

Phosphaniminato-Komplexe des Titans. Synthese und Kristallstrukturen von CpTiCl2(NPMe3), [TiCl3(NPMe3)]2, [Ti2Cl5(NPMe2Ph)3] und [Ti3Cl6(NPMe3)5][BPh4]

Phosphoraneiminato Complexes of Titanium. Synthesis and Crystal Structures of CpTiCl₂(NPMe₃), [TiCl₃(NPMe₃)]₂, [Ti₂Cl₅(NPMe₂Ph)₃], and [Ti₃Cl₆(NPMe₃)₅][BPh₄] The title compounds are formed from Cp₂TiCl₂ and titanium tetrachloride, respectively, and the corresponding phosphane imino compounds Me₃SiNPMe₃ and Me₃SiNPMe₂Ph. The tetraphenyl borate salt yielded from the reaction of [Ti₃Cl₆(NPMe₃)₅]Cl with NaBPh₄. All compounds form yellow crystals which are sensitive to moisture. They were characterized by IR-spectroscopy and crystal structure analyses. CpTiCl₂(NPMe₃) ( 1 ): Space group Pbca, Z = 8, solution of the structure with 1632 observed independent reflections, R = 0.037. Lattice dimensions at 19°C: a = 1202.6, b = 1224.2, c = 1766.7 pm. The molecules of the compound are monomeric with the (NPMe₃)^? ligand in almost linear array (bond angle Ti? N? P 170.7°). [TiCl₃(NPMe₃)]₂ ( 2 ): Space group Pbca, Z = 8, structure solution with 698 observed independent reflections, R = 0.030. Lattice dimensions at ?60°C: a = 1140.5, b = 1112.2, c = 1589.4 pm. In 2 the titanium atoms, which occur in trigonal bipyramidal coordination, are linked by the N atoms of the (NPMe₃)^? groups to form a centrosymmetric dimer with Ti? N bond lengths of 184.3 and 208.2 pm. [Ti₂Cl₅(NPMe₂Ph)₃] · CH₂Cl₂ ( 3 ): Space group Pca2₁, Z = 4, structure solution with 8477 observed independent reflections, R = 0.051. The lattice dimensions at 20°C are: a = 1221.0; b = 1407.5, c = 2139.3 pm. 3 can be understood as a reaction product of TiCl₂(NPMe₂Ph)₂ and TiCl₃(NPMe₂Ph). In the resulting, heavily distorted Ti₂N₂-four-membered ring the Ti? N bond lenghts are 1804., 194.4, 199.2, and 234.6 pm. The longest Ti? N bond is in trans-position to the N atom of the terminal (NPMe₂Ph)- ligand, in which the Ti? N distance is 175.6 pm. .[Ti₃CL₆(NPMe₃)₅][BPh₄] (4): Space group P2₁/n, structure solution with 2846 observed independent reflections, R = 0.062. The lattice dimensions at 20°C are: a = 1495.2, b = 2335.4, c = 155,8 pm, β = 93.28°. In the cation of 4 the three titanium atoms along with three (NPMe₃)- groups with μ2- N functions and two (NPMe₃)- groups with μ3- N functions form a nation number 6 with two terminal chlorine atoms.     

Inclusion complexes of the antitumour metallocenes Cp(2)MCl(2) (M = Mo, Ti) with cucurbit[n]urils

The encapsulation of the aquated forms of molybdocene dichloride and titanocene dichloride by cucurbit[n]uril (Q[n], where n = 7 and 8) at different pD values has been studied by (1)H NMR spectroscopy and molecular modelling. (1)H NMR titration experiments indicate that both metallocenes form 1 : 1 host-guest complexes with both Q[7] and Q[8]. In these complexes, both the cyclopentadienyl ligands and metal centre are positioned deep within the cucurbituril cavity. In vitro cell proliferation studies using the cancer cell lines MCF-7 and 2008 showed that the encapsulated molybdocene complex was more active than the corresponding free metallocene, with GI(50) values of 210 and 400 muM respectively. However, unexpectedly the encapsulation of Cp(2)MoCl(2(aq))at pD 7 catalysed significant degradation of the cucurbituril framework in the presence of oxygen. Encapsulation of Cp(2)TiCl(2(aq)) by Q[7] greatly slowed the protonolysis of the cyclopentadienyl ligands in aqueous phosphate buffer (pD 7), while encapsulation in Q[8] only slightly retarded the hydrolytic degradation of the metallocene.     

Nickel-manganese sulfido carbonyl cluster complexes. synthesis, structure, and properties of the unusual paramagnetic complexes Cp2Ni2Mn(CO)3(mu 3-E)2, E = S, Se

The reaction of Mn(2)(CO)(7)(mu-S(2)) with [CpNi(CO)](2) yielded the paramagnetic new compound Cp(2)Ni(2)Mn(CO)(3)(mu(3)-S)(2) (1) and a new hexanuclear metal product Cp(2)Ni(2)Mn(4)(CO)(14)(mu(6)-S(2))(mu(3)-S)(2) (2). Structurally, compound 1 contains two triply bridging sulfido ligands on opposite sides of an open Ni(2)Mn triangular cluster. EPR and temperature-dependent magnetic susceptibility measurements of 1 show that it contains one unpaired electron. The electronic structure of 1 was determined by Fenske-Hall molecular orbital calculations which show that the unpaired electron occupies a low lying antibonding orbital delocalized unequally across the three metal atoms. The selenium homologue Cp(2)Ni(2)Mn(CO)(3)(mu(3)-Se)(2) (3) was obtained from the reaction of a mixture of Mn(2)(CO)(10) and [CpNi(CO)](2) with elemental selenium and Me(3)NO.2H(2)O. It also has one unpaired electron. Compound 1 reacted with elemental sulfur to yield the dinickeldimanganese compound, Cp(2)Ni(2)Mn(2)(CO)(6)(mu(4)-S(2))(mu(4)-S(5)), 4, which can also be made from the reaction of Mn(2)(CO)(7)(mu-S(2)) with [CpNi(CO)](2) and sulfur. Compound 4 was converted back to 1 by sulfur abstraction using PPh(3). The reaction of Mn(2)(CO)(10) with [CpNi(CO)](2) in the presence of thiirane yielded the ethanedithiolato compound CpNiMn(CO)(3)(mu-SCH(2)CH(2)S) (5), which was also obtained from the reaction of Mn(4)(CO)(15)(mu(3)-S(2))(mu(4)-S(2)) with [CpNi(CO)](2) in the presence of thiirane. Compound 5 reacted with additional quantities of thiirane to yield the new compound CpNiMn(CO)(3)[mu-S(CH(2)CH(2)S)(2)], 6, which contains a 3-thiapentanedithiolato ligand that bridges the two metal atoms. Compound 6 was also obtained from the reaction of Mn(2)(CO)(10) with [CpNi(CO)](2) and thiirane. The molecular structures of the new compounds 1-6 were established by single-crystal X-ray diffraction analyses.     

Silanolato-Komplexe von Titan und Zirconium. Die Kristallstrukturen von Cp2TiCl(OSiPh3) und Cp2ZrCl(OSiPh3)

Silanolato Complexes of Titanium and Zirconium. The Crystal Structures of Cp₂TiCl(OSiPh₃) and Cp₂ZrCl(OSiPh₃) The title compounds have been prepared by the reaction of Cp₂MCl₂ (M = Ti, Zr) with triphenylsilanole in diethylether in the presence of piperidine. They form only sparingly moisture sensitive orange (Ti) or colourless (Zr) crystal needles, which were characterized by X-ray crystallography. Cp₂TiCl(OSiPh₃): Space group P2₁/n, Z = 4, structure solution with 3961 observed unique reflections, R = 0.057. Lattice dimensions at 20°C: a = 1029.6, b = 1719.3, c = 1388.9 pm, β = 100.69°. The compound forms monomeric molecules with bond lengths TiO of 184.2 pm, SiO of 161.5 pm, and a TiOSi bonding angle of 164.5°. Cp₂ZrCl(OSiPh₃): Space group P3 , Z = 18, structure solution with 2799 observed unique reflections, R = 0.047. Lattice dimensions at ?20°C: a = b = 3518, c = 1058.3 pm. The structure consists of three symmetry-independent monomeric molecules, which differ only slightly. The bond lengths are (in average): ZrO 196.4 pm, SiO 162.1 pm, the ZrOSi bond angle is 173.7°.     

Hydrolysis of CpTiCl2(TEMPO) and its application on one-pot syntheses of CpTiCl(OR)2 complexes

The eta1-hydroxylamido half-titanocene complex, CpTiCl2(TEMPO) 1, hydrolyzes extremely efficiently to generate (CpTiClO)4 and the protonated hydroxylamine. The efficient hydrolysis chemistry provides selective syntheses of CpTi dialkoxide and diaryloxide complexes.     

Synthesis and X-ray crystal structure of complexes Cp(CO)2MnP(SR)3 (R = Pri,Ph)

Cp(CO)₂Mn · THF reacts in THF with thiosters of phosphorus acid, P(SR)₃, to give new complexes Cp(CO)₂MnP(SR)₃ in which the manganese atom is coordinated to the phosphorus atom. The X-ray crystal structure of compounds with R = Prⁱ and Ph was established. The metal atom has a coordination enviroment of the three-legged piano stool type. The bond angles OC-Mn-CO and OC-Mn-P are 90.6–95.9(4)°. Bond distances are: Mn-P 2.188(2) and 2.171(2) E, P-S 2.097(3)-2.137(3) E.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1116–1119, June, 1994.This work was carried out with financial support from the Russian Foundation for Basic Research (Project No.93-03-5830).     

On the inductive effects of the organometallic groups M(CO) m Cp n and HgM(CO) m Cp n (M = Co,Mo, Mn,Fe, Re)

Based on the dependences v(CO) =a + b^* for IR spectra of carbonyi complexes of transition metals, the inductive constants of the organometallic fragments M(CO) _m Cp _n and HgM(CO) _m Cp _n (M = Co, Mo, Mn, Fe, Re) have been determined. The acceptor properties of the organometallic fragments have been shown to change according to the order of the nucleophilicity of the anions: Fe(CO)₂Cp > Re(CO)₅ > Mn(CO)₅ > Mo(CO)₃Cp > Co(CO)₄.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1482–1484, August, 1994.     

Complexes of decamethylsilicocene: Cp2*Si(CO) and Cp2*Si(N2)

The synthesis and IR spectroscopic detection of the monocarbonyl and mononitrogen complex of decamethylsilicocen in liquid xenon (LXe) and liquid nitrogen (LN₂) is reported. The reactions were found to be highly incomplete under a few bar of CO or N₂ and reversibel when the pressure is released. Cp₂*Si(CO) is characterized by three isotopomeres and Cp₂*Si(N₂) was synthesized on two independent routes.     

Synthesis and characterization of some bis(cyclopentadienyl)titanium(IV) complexes with internally functionalized oximes(LH): sol–gel transformations of Cp2TiCl2, Cp2TiClL and Cp2TiL2 to nano‐sized anatase titania

Some bis(cyclopentadienyl)titanium(IV) complexes of the type [Cp₂TiCl_2?n{L}_n] {where, n = 1 or 2; L = ONC(R)Ar; R = H or CH₃ and Ar = C₅H₄N‐2, C₄H₃O‐2 or C₄H₃S‐2} have been synthesized by the metathetical reactions of Cp₂TiCl₂ with the sodium salt of internally functionalized oximes in 1:1 and 1:2 stoichiometry in anhydrous THF. All these red to brown colored solid derivatives have been characterized by elemental analyses, FT‐IR and NMR (¹H and ¹³C{¹H}) spectral studies. The FAB mass spectra of some representative derivatives indicate their monomeric nature. Oximato ligands in all the complexes appear to bind the titanium via N and O in a dihapto ( ‐N, O) manner in the solid state. Thermogravimetric curves of [Cp₂TiCl{ONC(CH₃)C₅H₄N‐2}] and [Cp₂Ti{ONC(CH₃)C₅H₄N‐2}₂] suggest the formation of hybrid materials CpTiO(Cl) and Cp₂TiO, respectively, as the final products at 900 °C under nitrogen atmosphere. Sol–gel transformations of Cp₂TiCl₂, [Cp₂TiCl{ONC(CH₃)C₅H₄N‐2}] and [Cp₂Ti{ONC(CH₃)C₅H₄N‐2}₂] yielded titania a–c, respectively, at low sintering temperature (600 °C). The powder XRD patterns, IR as well as Raman spectra of all these oxides indicate the formation of nano‐sized anatase phase. The SEM images of titania a–c indicate agglomers like surface morphologies. The absorption spectra of a–c exhibit an energy band gap in the range of 3.47–3.71 eV. Copyright © 2011 John Wiley & Sons, Ltd.     

Ab initio investigation of vibrational spectra of water-(CO2)n complexes (n = 1, 2)

In this paper, we have calculated using the ab initio method the IR vibrational spectra of complexes of CO2 formed with water (sp3 O-donating atom). Binding energies and structures of the CO2-H2O and water-(CO2)2 complexes have been determined at the second-order level of the Moller-Plesset perturbation theory (MP2) using Dunning's basis sets. The results are presented and critically discussed in terms of the nature of the water-CO2 interactions, electron donor acceptor (EDA) and weak O...H-O interactions. For water-(CO2)2 trimer, it is also shown that the contribution to the interaction energy of the irreducible three-bodies remains relatively negligible. We have analyzed the frequency shifts and the IR and Raman intensity variations under the complex formation. We have particularly emphasized the splitting of the 2 bending mode of CO2 and stretching modes of water, which have been revealed as the most pertinent probes to assess the nature of the forces involved in the different complexes. Finally, because water can play the role of Lewis base and acid as well, we found that weak O...H-O interactions can cooperate with EDA interactions in trimer, leading to very specific spectral signatures that are further discussed.     

Reactions of [(Cp)2Ti(NCS)2] as a potential metalloligand; synthesis and physico-chemical investigations of novel heterobimetallic complexes

Summary Bis(cyclopentadienyl)titanium(IV) diisothiocyanate [(Cp)₂-Ti(NCS)₂] reacts with MCl₂ (M = Cu, Pd or Pt), [CuCl(PPh₃)₃], [RuCl₂(PPh₃)₃] and [RuCl₂(DMSO)₄] (DMSO = dimethylsulphoxide) giving solid compounds of stochiometry [(Cp)₂Ti(-NCS)₂MCl₂] (M = Cu, Pd or Pt), [(Cp)₂Ti(-NCS)₂CuCl(PPh₃)], [(Cp)₂Ti(-NCS)₂-RuCl(PPh₃)₂]Cl and [(Cp)₂Ti(-NCS)₂RuCl₂(DMSO)2]. These products have been characterized by physicochemical and spectroscopic methods.     

钛配合物Cp2TiL,Cp2Ti2Cl2(μ-O)和Cp4Ti4Cl4(μ-O)4的合成与晶体结构研究(Cp=η5-C5H5,L=2,6-吡啶二羧酸盐)

利用溶剂热的方法将Cp2TiCl2(Cp=η5-C5H5)与2,6-吡啶二羧酸钠(L)反应,不同的反应时间得到了2个具有不同晶体空间群的化合物Cp2TiL(1a和1b),而在常温或低温下,Cp2TiCl2或CpTiCl3同羧酸盐或亚胺反应却得到了双核或四核氧桥联的钛化合物。