(C_5H_9C_5H_4)_3NdBrLi(THF)_3和(C_5H_9C_5H_4)_3SmTHF的合成与结构

无水三氯化钕与环戊烷基环戊二烯钠、溴化锂(1:2:1摩尔比)反应,除去不溶物和溶剂后,产物在己烷/四氢呋喃溶剂中冷冻得到兰紫色晶体(C5H9C5H4)3NdBrLi(THF)3(配合物1)。其中心金属Nd3+的配位数为10,以η5与3个环戊二烯基相连,并通过单溴原子桥连锂原子,形成双核结构。该晶体属三斜晶系,P`1空间群。晶体学参数为a=12.048(2)、b=13.498(3)、c=13.831(3);α=104.16(3)、β=104.07(3)、γ=95.96(3); V=2083.3(7)3、Z=2、Dc=1.35Mg/m3、Mr=847.01gmol-1、F(000)=874。无水三氯化钐与环戊烷基环戊二烯钠(1:3)反应,产物在-30oC下的己烷溶剂中结晶得桔红色晶体(C5H9C5H4)3SmTHF(配合物2)。该晶体属正交晶系,Fdd2空间群。晶胞参数a=28.175(5) 、b=46.24(2)、c=9.167(4);V=11943(8)3、Z=16、Dc=1.38Mg/m3、 Mr=622.11 g·mol-1、F(000)=5136。10配位的金属Sm3+与3个环戊二烯基以η5相连,并结合一个四氢呋喃溶剂分子。     

Biferrocenium tetrabromoferrate, [(C5H5)Fe(C5H4)- (C5H4)Fe(C5H5)]FeBr4. The X-ray structural characterization of a mixed-valence compound

Biferrocenium tetrabromoferrate, [(C₅H₅)Fe(C₅H₄)-(C₅H₄)Fe(C₅H₅)]FeBr₄ (1) obtained as a by-product in the synthesis of biferrocenium trihalide salts, crystallizes in the noncentrosymmetric orthorhombic space group, P2₁2₁2₁: (at 296 K) a 7.492(2), b 9.903 (2), c 31.604(9) Å, V 2345(1) ų, and Z = 4. The cation, similar to other structurally characterized biferrocenium salts, adopts a trans-configuration, but, in contrast, possesses no crystallographically imposed symmetry relating the two ferrocenyl environments. Different average Fe-ring distances at the two environments: Fe(1), 2.02(2) and Fe(2), 2.08(2) Å are typical of iron(II) and iron(III) states, respectively, indicating the presence of trapped oxidation states. Interionic contacts are both shorter and more numerous for the iron(III) ferrocenyl fragment than for the iron(II) fragment. Both ferrocenyl units have non-eclipsed ring configurations, with a staggering angle of 6.5(3)° at Fe(1) and 23.5(3)° at Fe(2). The FeBr₄⁻ counterion is tetrahedral and ordered.     

Hydrolysis and chemical speciation of (C2H5)2Sn2+, (C2H5)3Sn+ and (C3H7)3Sn+ in aqueous media simulating the major composition of natural waters

The hydrolysis of (C₂H₅)₂Sn²⁺, (C₂H₅)₃Sn⁺ and (n‐C₃H₇)₃Sn⁺ has been studied, by potentiometric measurements ([H⁺]‐glass electrode), in NaNO₃, NaCl, NaCl/Na₂SO₄ mixtures and in a synthetic seawater (SSWE), as an ionic medium simulating the major composition of natural seawater, at different ionic strengths (0 ≤ I ≤ 5 mol dm^?3) and salinities (15 ≤ S ≤ 45), and at t = 25 °C. Five hydrolytic species for (C₂H₅)₂Sn²⁺, three for (C₂H₅)₃Sn⁺ and two for (C₃H₇)₃Sn⁺ are found. Interactions with the anion components of SSWE, considered as single‐salt seawater, are determined by means of a complex formation model. A predictive equation for the calculation of unknown hydrolysis constants of trialkyltin(IV) cations, such as tributyltin(IV), in NaNO₃, NaCl, and SSWE media at different ionic strengths is proposed. Equilibrium constants obtained are also used to determine the interaction parameters of Pitzer equations. Copyright © 2001 John Wiley & Sons, Ltd.     

Photochemical reactions of (CO)2 (PPh3)MnC5H4Fe(CO)2C5H5 and (CO)2(PPh3)MnC5H4COFe(CO)2C5H5 with PPh3

Conclusions The photochemical reactions of (CO)₂(PPh₃)MnC₅H₄Fe(CO)₂C₅H₅ and (CO)₂(PPh₃)MnC₅H₄COFe(CO)₂C₅H₅ with PPh₃ gave the products of replacing the CO on the Fe atom by PPh₃: respectively (CO)₂(PPh₃)MnC₅H₄Fe (CO)(PPh₃)C₅H₅ and (CO)₂(PPh₃)MnC₅H₄COFe(CO)(PPh₃)C₅H₅.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2813–2815, December, 1977.     

Microwave spectra and the metal-hydrogen bond lengths for the C5H5Mo(CO)3H and C5H5W(CO)3H complexes

The measurements of rotational spectra and metal-hydrogen bond lengths for molybdenum and tungsten hydride complexes were recently completed in our laboratory. The W-H and Mo-H bond lengths were obtained from high resolution rotational spectra of C5H5Mo(CO)3H, C5H5W(CO)3H, C5H5Mo(CO)3D, and C5H5W(CO)3D. Data for five molybdenum and four tungsten isotopomers were obtained for both the normal and deuterium-substituted species. The asymmetric-top rotational parameters A, B, C, DeltaJ, and deltaJ were determined from the least-squares fits and these results indicate that the structures of these complexes are nearly rigid. The hydrogen bond lengths were determined for both complexes using Kraitchman analyses. The molybdenum-hydrogen bond length for the C5H5Mo(CO)3H complex is rMo-H=1.80(1) A. The tungsten-hydrogen bond length for the C5H5W(CO)3H complex is rW-H=1.79(4) A. Density functional theory (DFT) calculations of the structures were performed to obtain the optimized theoretical structures for C5H5Mo(CO)3H and C5H5W(CO)3H. Results obtained from the DFT calculations are in good agreement with the experimental parameters, and the Mo-H value is in good agreement with previously reported Mo-H bond lengths for similar complexes.     

Zur Polyreaktion von Äthylen mit dem löslichen Ziegler-Natta-Katalysator (C5H5)2Ti(C2H5)Cl/Al(C2H5)Cl2

Ohne Zusammenfassung     

Zur disproportionierung der phenylfluorphosphane (C6H5)2PF und (C6H5)PF2

Ph₂P-PF₂Ph₂ has been identified by means ¹⁹F- and ³¹P- NMR spectroscopy as an intermediate product of the disproportionation of Ph₂PF. The disproportionation is catalyzed by acids. The reaction mechanism is discussed. PhPF₂ disproportionates faster in solution in acetonitrile than neat, forming (PhP)₆, instead of (PhP)₅.     

Protonated free-base corroles: acidity, electrochemistry, and spectroelectrochemistry of [(Cor)H4]+, [(Cor)H5]2+, and [(Cor)H6]3+

Protonated meso-substituted free-base macrocycles of the form [(Cor)H4]+, [(Cor)H5]2+, and [(Cor)H6]3+ where Cor is the trianion of a given corrole, were chemically generated from neutral (Cor)H3 in benzonitrile by addition of trifluoroacetic acid (TFA) and characterized as to their relative acidity, electrochemistry, and spectroelectrochemistry. Three types of protonated free-base corroles with different electron-donating or electron-withdrawing substituents at the meso positions of the macrocycle were investigated. One is protonated exclusively at the central nitrogens of the corrole forming [(Cor)H4]+ from (Cor)H3, while the second and third types of corroles undergo protonation at one or two meso pyridyl substituents prior to protonation of the central nitrogens and give as the final products [(Cor)H5]2+ and [(Cor)H6]3+, respectively. Altogether the relative deprotonation constants (pKa) for 10 different corroles were determined in benzonitrile and analyzed with respect to the molecular structure and/or type of substituents on the three meso positions of the macrocycle. Mechanisms for oxidation and reduction of the protonated corroles are proposed in light of the electrochemical and spectroelectrochemical data.     

Quantum-chemical study of silacyclohexanes C5H10SiHCN, C5H10SiH(t-Bu), C5H10Si(t-Bu)CN, and C5H10SiHF

By quantum-chemical calculations at the M06-2X/aug-cc-pVTZ level of theory geometrical parameters, dipole moments, polarizabilities, first hyperpolarizabilities and relative energies of the axial and equatorial conformers in gaseous phase were determined for 1-cyano-1-silacyclohexane, 1-tert-butyl-1-silacyclohexane, 1-tert-butyl-1-cyano-1-silacyclohexane, and 1-fluoro-1-silacyclohexane. For the cyano group and fluorine atom the axial position is more preferable whereas for tert-butyl group, equatorial one. Polarizabilities of conformers are similar but optical anisotropy of equatorial conformers of C₅H₁₀SiHCN and C₅H₁₀SiH(t-Bu) molecules is much larger than that of axial conformers. Upon substitution in nitriles of C¹ atom by Si atom the hyperpolarizability is many times increased.