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1.
Transformation products of the cationic rhodium complex [(1,5-COD)Rh(—)R,R-DIOP]+CF3SO3
– (1) (COD is cycloocta-1,5-diene and DIOP is (±)-2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane), which were obtained in its reactions with molecular hydrogen, base (NEt3), and solvents in the absence of a substrate, were investigated by 1H and 31P NMR spectroscopy. The solvate complexes [(Solv)2Rh(—)R,R-DIOP]+CF3SO3
–, which were generated from complex 1 in its reaction with molecular hydrogen, underwent destruction of the diphosphine ligand with elimination of benzene and were subjected to oxidation by traces of moisture and oxygen to form the DIOP dioxide complex with RhI. In the absence of hydrogen, complex 1 in solutions produced the diphosphine dioxide rhodium(i) complex and mono- and binuclear rhodium(i) solvate complexes. The scheme of deactivation of the complex in the absence of the substrate was proposed. The catalytic activity of the solvate complexes [(ArH)Rh(—)R,R-DIOP]+CF3SO3
–, which contain benzene, p-xylene, and mesitylene in the coordination sphere, was studied in hydrogenation of Z--acetamidocinnamic acid. 相似文献
2.
The reaction between acrylonitrile and the RuH bond in HRu(CO)Cl(PPh3)3 results in the formation of a binuclear ruthenium(II) complex having chlorine bridges which are easily broken by sodio-derivatives of bidentate chelating ligands giving mononuclear hexacoordinated ruthenium(II) compounds. The RuC bond in these new complexes has been found to be stable towards nucleophilic reagents. The stereochemistry for these complexes has been suggested on the basis of IR, 1H and 31P NMR spectra. 相似文献
3.
Gannon P. Connor Daniel Delony Jeremy E. Weber Brandon Q. Mercado Julia B. Curley Sven Schneider James M. Mayer Patrick L. Holland 《Chemical science》2022,13(14):4010
Rhenium complexes with aliphatic PNP pincer ligands have been shown to be capable of reductive N2 splitting to nitride complexes. However, the conversion of the resulting nitride to ammonia has not been observed. Here, the thermodynamics and mechanism of the hypothetical N–H bond forming steps are evaluated through the reverse reaction, conversion of ammonia to the nitride complex. Depending on the conditions, treatment of a rhenium(iii) precursor with ammonia gives either a bis(amine) complex [(PNP)Re(NH2)2Cl]+, or results in dehydrohalogenation to the rhenium(iii) amido complex, (PNP)Re(NH2)Cl. The N–H hydrogen atoms in this amido complex can be abstracted by PCET reagents which implies that they are quite weak. Calorimetric measurements show that the average bond dissociation enthalpy of the two amido N–H bonds is 57 kcal mol−1, while DFT computations indicate a substantially weaker N–H bond of the putative rhenium(iv)-imide intermediate (BDE = 38 kcal mol−1). Our analysis demonstrates that addition of the first H atom to the nitride complex is a thermochemical bottleneck for NH3 generation.Rhenium–PNP complexes split N2 to nitrides, but the nitrides do not give ammonia. Here, the thermodynamics of the hypothetical N–H bond forming steps are evaluated through the reverse reaction, showing that the first H addition is the bottleneck. 相似文献
4.
Ahmad Saeed Isab Anvarhusein A. Perzanowski Herman P. Hussain M. Sakhawat Akhtar M. Naseem 《Transition Metal Chemistry》2002,27(2):177-183
Phosphine sulfides and their gold(I) complexes with general formula R3P=S—Au—X (X = Cl–, Br– or CN–) were prepared and characterized by elemental analyses, i.r. and 31P-n.m.r. spectroscopy. A decrease in the i.r. frequency of the P=S bond in the ligands upon complexation, is indicative of S coordination to gold (I). The 31P-n.m.r. spectra revealed that electronegativity of the substituents and angles between them were the two most important factors influencing the 31P-n.m.r. chemical shifts. The phosphorus resonance was observed to be more downfield in alkyl substituted phosphine sulfides as compared to the aryl substituted phosphine sulfides. Ligand scrambling in the Cy3P=S—Au—CN complex in solution, to form [(Cy3P=S)2Au]+ and [Au(CN)2]–, was investigated by 13C and 15N-n.m.r. spectroscopy. Equilibrium constants (K
eq) for scrambling of the Cy3P=S—Au—CN complex and for its analogue, Cy3P=Se—Au—CN were measured by integrating the 13C-n.m.r. at 297 K and were found to be 0.147 and 1.81 respectively. 相似文献
5.
Strain‐Induced Double Carbon–Carbon Bond Activations of Cycloparaphenylenes by a Platinum Complex: Application to the Synthesis of Cyclic Diketones
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Dr. Eiichi Kayahara Toshiki Hayashi Dr. Katsuhiko Takeuchi Prof. Dr. Fumiyuki Ozawa Keita Ashida Prof. Dr. Sensuke Ogoshi Prof. Dr. Shigeru Yamago 《Angewandte Chemie (International ed. in English)》2018,57(35):11418-11421
The carbon–carbon (C?C) bond activation of [n]cycloparaphenylenes ([n]CPPs) by a transition‐metal complex is herein reported. The Pt0 complex Pt(PPh3)4 regioselectively cleaves two C?C σ bonds of [5] CPP and [6]CPP to give cyclic dinuclear platinum complexes in high yields. Theoretical calculations reveal that the relief of ring strain drives the reaction. The cyclic complex was further transformed into a cyclic diketone by using a CO insertion reaction. 相似文献
6.
Schultz György Hargittai István Rot Nicolette Bickelhaupt Friedrich 《Structural chemistry》1998,9(3):209-214
The molecular structure of 1,3,5-tris (trimethylstannyl) benzene has been determined by gas-phase electron diffraction. The C — C bond length is in good agreement with that in benzene. In agreement with the somewhat electron-releasing character of the substituents, the endocyclic bond angles at the substituents are somewhat smaller than 120°. The mean value of Sn — C bond lengths is greater than that in tetraphenyltin and tetramethyltin. The SnMe3 groups appear freely rotating around the Caryl — Sn bonds. The following bond lengths (r
g) and bond angles were determined: (Sn — C)mean 2.150 ± 0.007 Å, C — C 1.399 ± 0.005 Å, (C — H)mean 1.105 ± 0.006 Å, < C — C(Sn) — C 117.7 ± 1.7º, < Caryl — Sn — Cmethyl 106.7 ± 0.7º < Sn — C — H 111.5 ± 0.9º. 相似文献
7.
Tikhonova I. A. Shubina E. S. Dolgushin F. M. Tugashov K. I. Teplitskaya L. N. Filin A. M. Sivaev I. B. Petrovskii P. V. Furin G. G. Bregadze V. I. Epstein L. M. Shur V. B. 《Russian Chemical Bulletin》2003,52(3):594-600
The reaction of cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4Hg)3 (1) with the polyhedral [B12H11SCN]2– anion in THF at 20 °C affords the {[(o-C6F4Hg)3](B12H11SCN)}2– (4) and {[(o-C6F4Hg)3]2(B12H11SCN)}2– (5) complexes. Complex 5 was isolated as the tetrabutylammonium salt. X-ray diffraction analysis showed that this complex has a bent-sandwich structure in which the [B12H11SCN]2– anion is located between the planes of two molecules 1 and is coordinated to both these molecules through B—H—Hg bridges and S—Hg bonds. The stability constants of complexes 4 and 5 in THF (20 °C), which were determined from the IR spectroscopic data, are 16 L mol–1 and 992 L2 mol–2, respectively. 相似文献
8.
Mnica Martínez-Estvez Soledad García-Fontn Saray Argibay-Otero Inmaculada Prieto Ezequiel M. Vzquez-Lpez 《Molecules (Basel, Switzerland)》2022,27(22)
The reaction of [Ru2Cl2(μ-Cl)2(η6-p-cymene)2] with two thiosemicarbazones obtained by the condensation of N-(4-methoxybenzyl) thiosemicarbazide and 1,4-hydroxy-3-methoxyphenyl)ethan-1-one (HL1) or 2-fluoro-4-hydroxybenzaldehyde (HL2) was studied. The cationic complexes of formula [RuCl(η6-p-cymene)(HL)]+ were isolated as solid chloride and trifluoromethylsulfate (TfO) salts. A study of the solid state and NMR spectra suggests the presence in the material of two isomers that differ in the configuration in the iminic bond, C2=N3, of the coordinated thiosemicarbazone in the triflate salts and only the E isomer in the chloride. An X-ray study of single crystals of the complexes supports this hypothesis. The thiosemicarbazone ligand coordinates with the ruthenium center through the iminic and sulfur atoms to form a five-membered chelate ring. Furthermore, the isolation of single crystals containing the thiosemicarbazonate complex [Ru2(μ-L2)2(η6-p-cymene)2]2+ suggests the easy labilization of the coordinated chloride in the complex. The redox behavior of the ligands and complexes was evaluated by cyclic voltammetry. It seems to be more difficult to oxidize the complex derived from HL1 than HL2. The ability of the complexes to inhibit cell growth against the NCI-H460, A549 and MDA-MB-231 lines was evaluated. The complexes did not show greater potency than cisplatin, although they did have greater efficacy, especially for the complex derived from HL1. 相似文献
9.
Reactions of VO(acac)2 with alkylene dithiophosphoric acids, POGOS2H, and of VOCl3 with the ammonium salts NH4(POGOS2) in 1:2 molar ratio gave the oxovanadium(IV) alkylene dithiophosphates, [VO(POGOS2)2], and monochloroxovanadium(V) alkylene dithiophosphates, [VOCl(POGOS2)2], respectively, where G = —CH2CMe2-CH2—, —CH2CEt2CH2—, —CHMeCH2CMe2— or —CMe2CMe2—. These complexes are green solids, soluble in common organic solvents and sensitive to moisture. They were characterized by elemental analysis, molecular weight and spectral studies including i.r. and n.m.r. (1H, 13C and 31P), which suggested bidentate bonding of the POGOS2 ligands to give a square pyramidal for the VIV complexes and an octahedral geometry for the VV complexes. 相似文献
10.
Siwei Bi Yuxia Liu Guang Chen Lisheng Zhang Min Sun Ping Li 《Journal of organometallic chemistry》2009,694(21):3456-3461
Selective formation of (η3-siloxyallyl)tungsten complexes by reaction of hydrido(hydrosilylene)tungsten complexes with α,β-unsaturated carbonyl compounds was reported experimentally. The mechanisms have been investigated by employing the model reaction of [Cp(CO)2(H)WSi(H)–{C(SiH3)3}] (R), derived from the original experimental complex Cp′(CO)2(H)WSi(H)–[C(SiMe3)3] (1a, Cp′ = Cp*; 1b, Cp′ = η5-C5Me4Et), with methyl vinyl ketone, under the aid of the density functional calculations at the b3lyp level of theory. It is theoretically predicted that the route involving migration of the hydride to silicon to afford a 16e intermediate [Cp(CO)2W–SiH2–{C(SiH3)3}] is inaccessible (route 2), supporting the proposition by experiments. Another route, via [2 + 4] cycloaddition followed by directly Si–H reductive elimination, is theoretically predicted to be accessible (route 1). In route 1, two possible paths with different attacking directions of the oxygen of methyl vinyl ketone at Si (WSi) are put forward. The attack at the Si atom from the hydride (H1) side of the plane W–Si–H1 in R is found to be preferred kinetically. The regioselectivity for formation of (η3-siloxyallyl)tungsten complexes, where only the exo-anti isomer was obtained, is discussed based on the consideration of thermodynamics and kinetics. 相似文献
11.
Kimel" B. G. Tumanov V. V. Faustov V. I. Promyslov V. M. Egorov M. P. Nefedov O. M. 《Russian Chemical Bulletin》2002,51(8):1568-1574
Reactions of a number of germylenes and dimethylsilylene with a phosphaalkene, 2,2-bis(trimethylsilyl)-1-phenyl-1-phosphaethene (1), were studied. The reaction of short-lived dimethylgermylene with 1 produced a phosphagermirane 3 (the first representative of a new class of heterocyclic compounds). Compound 3 was characterized in solution by 1H, 13C, 31P, and 29Si NMR spectroscopy. Subsequent reaction of 3 with dimethylgermylene results in 2,2,3,3-tetramethyl-4,4-bis(trimethylsilyl)-1-phenyl-2,3-digerma-1-phosphacyclobutane 4, which has not been reported so far. In order to rationalize different reactivities of germylenes towards alkenes and phosphaalkenes, the addition products of GeH2 to ethylene and phosphaethene (HP=CH2) were studied using the G2 computational scheme and DFT PBE technique. The adducts of GeMe2 (GeCl2) with HP=CH2 and of GeMe2 with PhP=C(SiH3)2 were also calculated by the DFT PBE method. According to calculations, the exothermicity, DE, of cycloaddition of GeH2 and GeMe2 to the phosphaalkenes HP=CH2 and PhP=C(SiH3)2 (43.5—39.7 kcal mol–1) is nearly twice as high as the exothermicity of cycloaddition of these germylenes to ethylene. In addition to the minimum corresponding to the three-membered cycle, a number of minima corresponding to quite stable donor-acceptor complexes in which the Ge atom is coordinated by the lone electron pair of the P atom in the phosphaalkene molecule were located on the potential energy surface of the germylene—phosphaalkene system. The complexation energy of the complex of GeH2 (GeMe2) with phosphaethene is 25.0 (16.9) kcal mol–1. For GeCl2, the exothermicity of cycloaddition to HP=CH2 decreases to 7.6 kcal mol–1 and the complexation energy decreases to 8.2 kcal mol–1. 相似文献
12.
Borisova I. V. Nechaev M. S. Khrustalev V. N. Zemlyanskii N. N. Ustynyuk Yu. A. 《Russian Chemical Bulletin》2002,51(5):721-753
The review surveys the data on the reactions of phosphorus and arsenic ylides with compounds containing E=X bonds (E = C, Si, Ge, or Sn; X = C or S), cyclic oligomers (R2ES)n (n = 2 or 3), and heavier analogs of carbenes. These reactions give rise to two new classes of heteroorganic betaines containing the (+)E15—C—E14—X(–) (I) and (+)E15—C—E14(–) (II) (E15 = P or As; E14 = Si, Ge, or Sn; X = C or S) structural fragments. Procedures for the synthesis of these compounds, their reactivities, the X-ray diffraction structures, and the electronic structures established by high-level quantum-chemical calculations are considered in detail. The carbon analogs of betaines of type I, viz., compounds bearing the (+)P—C—C—X(–) fragment (III), are also discussed. The latter were long considered as possible intermediates in the reactions of compounds containing the polar C=X bond (X = C, O, S, NR, etc.) with phosphorus ylides (classical Wittig and Corey—Chaykovsky reactions and related processes). 相似文献
13.
Asymmetric 7-formyanil-substituted-imino-4-(4-methyl-2-butanone)-8-hydroxyquinoline-5-sulphonic acid (Schiff bases), react with CoII, NiII and CuII ions to give 1:2, 1:1 and 2:1 complexes as established by conductometric titrations in 1:1 DMF:H2O. The complexes were investigated by elemental analyses, molecular weight determinations, molar conductance, magnetic moments, thermal analysis, i.r., u.v.–vis. and e.s.r. spectra. The complexes have an octahedral crystal structure and general formula [ML·(OH2)2], where MII = Co, Ni and Cu, and L = Na[7—X—HL], (—X— = (CH2)2, (CH2)3, p-C6H4, o-C6H4). Antimicrobial activity of these new ligands and their transition metal complexes has been screened in vitro on common fungi and bacteria. 相似文献
14.
The first example of palladium-catalyzed stereoselective addition of diphenyl disulfide and diphenyl diselenide to the triple bond of terminal alkynes under microwave irradiation conditions is described. It was found that both the element—element (E-E) and carbon—element bonds can be activated in the catalytic system studied. The products of both reactions were isolated in quantitative yields. According to quantum-chemical calculations, the reaction mechanism involves the oxidative addition of the E-E bond to Pd0. Depending on the microwave power and reaction conditions, the next stage is either the reaction with alkyne or the carbon—element bond activation. The product of the oxidative addition of Ph2Se2 to Pd0, namely, dinuclear complex [Pd2(SePh)4(PPh3
2], was detected by 31P{1H}NMR spectroscopy directly in the Ph2Se2/PPh3 melt formed under microwave irradiation conditions.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 569–580, March, 2005. 相似文献
15.
D. M. Roitershtein M. E. Minyaev K. A. Lyssenko P. A. Belyakov M. Yu. Antipin 《Russian Chemical Bulletin》2004,53(10):2152-2161
The reactions of dipotassium and disodium salts of the tetraphenylethylene dianion with LuCl3(THF)3 or CpLuCl2(THF)3 yielded the homoleptic ate-complexes [Na(THF)5][Lu(Ph2CCPh2)2] (1) and [K(THF)5][Lu(Ph2CCPh2)2] (2) or the heteroleptic complex CpLu(Ph2CCPh2)(THF)2 (4), respectively. Recrystallization of complex 1 from a diglyme—THF mixture afforded [Na(diglyme)2][Lu(Ph2CCPh2)2](THF)0,5 (3). Recrystallization of complex 4 from 1,2-dimethoxyethane gave [CpLu(Ph2CCPh2)(DME)](DME) (5). The structures of complexes 3 and 5 were established by X-ray diffraction analysis. In both complexes, the unusual η6-coordination of the (Ph2CCPh2)2− dianion to lutetium is observed. The Lu-C distances vary from 2.441(2) to 2.643(2) Å (3) and from 2.470(3) to 2.763(3) Å (5). In complexes 3 and 5, a redistribution of the C-C bond lengths was observed in the Ph groups coordinated to lutetium. Studies by 1H, 13C, and 2D NMR spectroscopy demonstrated that the η6-coordination of the tetraphenylethylene dianion in homoleptic ate-complexes 1 and 2 is retained in a THF solution, whereas the coordination of this dianion in heteroleptic complex 4 changes from η6 to η4.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2060–2068, October, 2004. 相似文献
16.
The positronium spin exchange (SE) reactions promoted by the 3d complexes Mn
aq
2+
, Co
aq
2+
, [Cr(NH3)6]3+, [Cr(NH3)5H2O]3+, and [Cr(H2O)5Cl2+] were investigated at different temperatures in order to ascertain whether they were diffusion controlled like those promoted by Cr
aq
3+
, Fe
aq
2+
, Ni
aq
2+
and [Ni(NH3)6]
aq
2+
ions studied previously.It was found that the reactions are diffusion controlled and that the effective reaction radii deduced from the Smoluchowski equation are smaller than the compound radii calculated from bond lengths and angles. It was also found that the rate constants, and therefore the reaction radii, are correlated with the spin—orbit coupling of 3d unpaired electrons and ligand capabilities to cause expansion of the d-electron cloud (nephelauxetic effect). In particular the effective reaction radii of SE reactions promoted by 3d complexes increase as the electron delocalization from 3d atoms increases.Work supported by Ministero Università e Ricerca Scientifica e Tecnologica (M.U.R.S.T.) and by Consiglio Nazionale Ricerche (C.N.R.). 相似文献
17.
Leites L. A. Bukalov S. S. Zabula A. V. Lyubetskii D. V. Krylova I. V. Egorov M. P. 《Russian Chemical Bulletin》2004,53(1):33-44
Temperature study of Raman spectra of alkylgermanes (Alk = Bun, n-C6H13) in liquid, polycrystalline, and glassy states was carried out. The spectra of liquid samples are complicated, because compounds exist as equilibrium mixtures of rotational isomers due to hindered rotation about C—C and Ge—C bonds. In crystals, only the most stable conformer persists, which results in simplification of the spectrum. Unlike n-hexylgermanes, n-butylgermanes crystallize on cooling with difficulties. Quantum-chemical calculations of the geometry and normal coordinate analysis of the possible conformers of the BunGeH3, BunGeCl3, and Bun
2GeCl2 molecules were performed. The unusually large (65 cm–1) difference between the experimental (Ge—C) stretching frequencies of the trans and gauche conformers about the C—C bond nearest to the Ge atom is attributed to the difference in the electronic structure of these conformers, which is manifested in the differences in the Ge—C bond lengths, molecular geometry, and their force fields and, consequently, affects the mode frequencies and eigenvectors. 相似文献
18.
Bo Fang Lei Zhang Guohua Hou Guofu Zi De-Cai Fang Marc D. Walter 《Chemical science》2015,6(8):4897-4906
Inter- and intramolecular C–H bond activations by thorium metallacyclopropene complexes were comprehensively studied. The reduction of [η5-1,2,4-(Me3C)3C5H2]2ThCl2 (1) with potassium graphite (KC8) in the presence of internal alkynes (PhCCR) yields the corresponding thorium metallacyclopropenes [η5-1,2,4-(Me3C)3C5H2]2Th(η2-C2Ph(R)) (R = Ph (2), Me (3), iPr (4), C6H11 (5)). Complexes 3–5 derived from phenyl(alkyl)acetylenes are very reactive resulting in an intramolecular C–H bond activation of the 1,2,4-(Me3C)3C5H2 ligand. In contrast, no intramolecular C–H bond activation is observed for the diphenylacetylene derived complex 2, but it does activate α-C–H bonds in pyridine or carbonyl derivatives upon coordination. Density functional theory (DFT) studies complement the experimental studies and provide additional insights into the observed reactivity. 相似文献
19.
Two new CuII complexes, [Cu(Hambi)2(ClO4)2] and [Cu(Hambi)2(dca)2] (Hambi = 2-aminomethylbenzimidazole) have been prepared and characterized by X-ray diffraction, electronic paramagnetic resonance (e.p.r.) and i.r. analyses. Both complexes exhibit an elongated octahedral coordination environment with two Hambi ligands situated at the equatorial positions in a trans fashion [Cu—N bond distances range from 1.940(9) to 2.031(9) Å]. In the second complex, a new coordination mode, in which dicyanamide coordinates to copper(II) as a monodentate ligand with the amide nitrogen atom, was observed. 相似文献
20.
Square planar palladium(II) aryl-amido complexes of diphosphinoazines in monoanionic unsymmetrical PNP’ pincer-type coordination were prepared by reactions of phenyl-, o-tolyl-, or 2,6-dimethylphenyllithium with previously described chloro-amido complexes of diphosphinoazines having isopropyl, cyclohexyl and tert-butyl substituents on phosphorus atoms. The compounds were characterized by NMR showing free rotation around metal-aryl bond in the complexes; the presence of Cipso-Pd bond was detected by two-dimensional experiments. In addition to that, crystal and molecular structure of one phenyl-amido complex, [Pd(C6H5){P(C6H11)2CHC(But)NNC(But)CH2P(C6H11)2}], was determined by X-ray diffraction together with the structure of a chloro-amido complex [PdCl{PBut2CHC(But)NNC(But)CH2PBut2}]. In both structures the ligand trans to the amide nitrogen is well surrounded by substituents on phosphorus atoms, the former complex showing significant interactions between two cyclohexyl hydrogen atoms and the π-system of the phenyl ring. The values od Pd-C and Pd-N bond distances in this complex are the same as those in a monodentate analog [Pd(PMe3)2(C6H5)(NHC6H5)] which contrasts with the different values in a similar PNP symmetrical pincer complex reported in the literature. 相似文献