共查询到20条相似文献,搜索用时 15 毫秒
1.
Ivan A. Portnyagin 《Journal of organometallic chemistry》2009,694(19):3149-8653
A series of germylene and stannylene (Me2NCH2CH2O)2E (E = Ge, 1; E = Sn, 2) complexes of group 6 metals and iron carbonyls L·M(CO)n (M = Cr, Mo, W, n = 5 (3-8), n = 4 (9, 10); M = Fe, n = 4 (11, 12)) were prepared. These complexes were characterized by 1H, 13C NMR, FTIR and elemental analysis. Ligand properties of 1 and 2 were compared to PPh3 and dmiy (N,N′-dimethylimidazolin-2-ylidene) using theoretical calculations (PBE/TZ2P) and FTIR. Ligand dissociation energies increase in the order Ph3P < 2∼1 < dmiy, while donor strength rise in the order PPh3 < dmiy < 2 < 1. 相似文献
2.
It has been suggested recently that the alanes AlnHn + 2 can be treated by the polyhedral skeletal electron pair theory (PSEPT) of Wade and Mingos (W-M) as it was successful for their borane congeners such as BnHn + 2, well known as the deprotonated BnHn2−. To do so, the neutral AlnHn + 2 have been considered as AlnHn2− + 2H+. The additional hydrogens donate their electrons to the AlnHn polyhedral framework and according to the n + 1 electron pairs rule; these clusters should have closo-polyhedral structures. In this work the homologous gallanes, the structures and stabilities of GanHn + 2 are studied at high levels of calculational theory and we investigated the applicability of the W-M rule to the alanes and gallanes AnHn + 2 (n = 4-6; A = Al, Ga). It will be shown that the presence of bridging hydrogen atoms reduces the compactness of the corresponding polyhedron and so these species do not have the closed structures. The computations were performed at B3LYP/6-311+G(d,p), BPW91/6-311G(d,p) and B3LYP/6-311+G(3df,2p) levels of theory. Our interest in these compounds includes their potential use as hydrogen storage species and future clean sources of energy. 相似文献
3.
Vandna Luthra Keith F.E. Pratt Robert G. Palgrave David E. Williams R.P. Tandon Ivan P. Parkin 《Polyhedron》2010
As part of a systematic study of mechanisms of response of semiconducting oxides as trace gas sensors, we have explored the behaviour of iron–titanium oxide solid solutions Fe2−xTixO3 (x = 0.1–1.4). The materials were single-phase for x = 0.1 with increasing proportions of a pseudobrookite second phase at higher degree of substitution. Unmodified, pure iron oxide does not show sensitivity to CO. A significant signal was developed for x = 0.1, that then diminished with increasing x and was lost for x = 1.4. Three effects have been deduced important for the gas response: significant surface segregation of Ti at low Ti content; grain growth inhibition and agglomeration into more massive, non-porous lumps as Ti content increased; and the appearance of a band-gap state associated with Fe(II) at higher Ti content. The effects of microstructure change have been analyzed by fitting the data to a simple 2-resistor model of gas-insensitive ‘grains’ in series with gas-sensitive ‘grain boundaries’. A Mars–van Krevelen type model for the response is presented, based on reactions at surface-segregated defect clusters, to develop and remove electrically-active surface trap states. 相似文献
4.
合成了2个新的配合物Eu2(btb)3(H2O)4(1)和Eu2(btb)3(phen)2(2)[H2btb=4,4′-双(4″,4″,4″, -三氟代 - 1″,3″-二氧代丁基)联苯, phen=1,10-邻菲罗啉]. 采用元素分析、红外光谱、紫外光谱和快原子轰击质谱表征了2个配合物的结构. 在近紫外光激发下, 配合物1和2都发射出强的铕离子特征红光. 对614 nm 红光进行监控, 其激发光谱在395 nm处具有最大的激发强度, 与InGaN芯片发射的近紫外光激发相匹配. 将配合物1和2与395 nm 发射的InGaN芯片进行组合制备了红色发光二极管. 在配合物和硅树脂的质量比为1∶25的情况下, 2个红色发光二极管的色坐标分别为x1=0.5210, y1=0.2285(配合物1); x2=0.5835和y2=0.2857(配合物 2), 位于标准的国际色坐标红色区域; 器件的发光效率分别为0.65和0.76 lm/W. 研究结果表明, 配合物1和2是制作白光二极管可供选用的红色发光材料. 相似文献
5.
Evans O. Changamu 《Journal of organometallic chemistry》2007,692(5):1138-1149
The alkyl-bridged iron(II) complexes [{Cp(CO)2Fe}2{μ-(CnH2n)}] (n = 6-10, Cp = η5-C5H5) undergo both single and double hydride abstraction when reacted with one equivalent of Ph3CPF6 to give both the monocationic complexes, [{Cp(CO)2Fe}2{μ-(CnH2n−1)}]PF6, and the dicationic complexes, [{Cp(CO)2Fe}2{μ-(CnH2n−2)}](PF6)2. The ratios of monocationic to dicationic complexes decrease with the increase in the value of n. The complexes where n = 4 and 5 undergo only single hydride abstraction under similar conditions. When reacted with two equivalents of Ph3CPF6, the complexes where n = 6-10 undergo double hydride abstraction to give dicationic complexes only. In contrast, the complex where n = 5 gives equal amounts of the monocationic and the dicationic complexes, while the complex where n = 4 only gives the monocationic complex. 1H and 13C NMR data show that in the monocationic complexes one metal is σ-bonded to the carbenium ion moiety while the other is bonded in a η2-fashion forming a chiral metallacylopropane type structure. In the dicationic complexes both metals are bonded in the η2-fashion. The monocationic complexes where n = 4-6, react with methanol to give η1-alkenyl complexes[Cp(CO)2Fe(CH2)nCHCH2] (n = 2-4) as the major products and σ-bonded ether products [{Cp(CO)2Fe}2{μ-(CH2)nCH(OCH3)CH2}] as the minor products. The complex where n = 8 reacted with iso-propanol to give the η1-alkenyl complex [Cp(CO)2Fe(CH2)6CHCH2]. The dicationic complexes where n = 5, 8 and 9 were reacted with NaI to give the respective α, ω-dienes and [Cp(CO)2FeI]. 相似文献
6.
Magdalena Ćwikowska Florian P. Pruchnik Oleksiy Pavlyuk Frédéric Lafolet Sylvie Chardon-Noblat Alain Deronzier 《Polyhedron》2010
Binuclear Rh(II) compounds [Rh2(μ-OOCCH3)2(dbbpy)2(H2O)2](CH3COO)2 (1) (dbbpy = 4,4′-di-tert-butyl-2,2′-bipyridine), [Rh2(μ-OOCCH3)2(dbbpy)2(H2O)2](BF4)2·H2O·CH3CN (2), [Rh2(CH3COO)2(C18H24N2)2(CH3CN)2](BF4)2·4CH3CN (3) and {[Rh2(μ-OOCCH3)2(dbbpy)2][BF4]}n (4) have been synthesized and characterized with spectroscopic methods. Structure of complex 3 has been determined using X-ray crystallography. Rhodium atoms in compound 3 have distorted octahedral coordination with O and N atoms in equatorial positions and Rh atom and CH3CN molecule in axial coordination sites. Reduction of rhodium(II) compounds with aqueous 2-propanol leads to the formation of polymetallic compound {[Rh2(μ-OOCCH3)2(dbbpy)2][BF4]}n (4) containing [Rh2]3+ core. Compound 4 shows strong antiferromagnetic properties, μ = 0.18–1.73 M.B. in the range 1.8–300 K, J = −597 cm−1. Electrochemistry of compounds 3 and 4 in CH3CN has been investigated. Compound 4 exhibits a poorly reversible oxidation system at E1/2 = −0.92 V (ΔEp = 0.19 V) and in solution in DMF is slowly oxidized to 3 even in total absence of oxygen. Complex 3 is irreversibly oxidized to Rh(III) compound at Epa = 1.48 V and irreversibly reduced at Epc = −1.02 V to lead to the unstable polynuclear complex 4 in CH3CN. 相似文献
7.
Marilia I. Frazão Barbosa Eliana M.A. Valle Salete L. Queiroz Javier Ellena Eduardo E. Castellano Valéria R.S. Malta Jackson R. de Sousa Oscar Piro Márcio P. de Araujo Alzir A. Batista 《Polyhedron》2010
The “Ru(P–P)” unit (P–P = diphosphine) is recognized to be an important core in catalytic species for hydrogenation of unsaturated organic substrates. Thus, in this study we synthesized six new complexes containing this core, including the binuclear complex [(dppb)(CO)Cl2Ru-pz-RuCl2(CO)(dppb)] (pz = pyrazine) which can be used as a precursor for the synthesis of cationic carbonyl species of general formula [RuCl(CO)(dppb)(N–N)]PF6 (N–N = diimine). Complexes with the formula [RuCl(py)(dppb)(N–N)]PF6 were synthesized by exhaustive electrolysis of these carbonyl compounds or from the precursors [RuCl2(dppb)(N–N)]. The new complexes were characterized by microanalysis, conductivity measurements, IR and 31P{1H} NMR spectroscopy, cyclic voltammetry and X-ray crystallography. 相似文献
8.
9.
Mien Wei Lum 《Journal of organometallic chemistry》2003,687(1):203-208
Reaction of the cluster Os3(μ-H)(μ-OH)(CO)10 (1) with 1-naphthol afforded the isomeric clusters 2a and 3a with the formulae Os3(μ-H)2(μ3-1-OC10H6)(CO)9. A similar reaction with 2-naphthol, however, gave Os3(μ-H)(μ-2-OC10H7)(CO)10, 4b, and the analogue of 2a. These clusters have been structurally characterised to confirm the mode of anchoring of the naphthols. 相似文献
10.
11.
The impact of the HF cluster size on the proton-transfer switch between N−?H-F and N-H?F− in the anilide-(HF)n = 1-4 complexes was investigated by means of the quantum chemical methods. The change in the H-bond strength due to variation of the HF cluster size was well monitored by change in the binding energy (BE), structural parameter, electron density topology, natural charge and charge transfer. For n = 1, our results at the MP2/6-311++G(2d,2p) level show that the minimum-energy structure corresponds to the H-bonded complex PhNH−?HF with excess negative charge localized on the N atom of the anilide anion. For n > 1, minimum energy structures correspond to PhNH2?F−(HF)1-3 ones, namely a solvated F− ion. This is a case in which the relative change in the acidity of the HF is observed in the ground state as the size of cluster increases. The nature of the weak interactions in the complexes was characterized by means of atoms in molecules (AIM) and the natural bond orbital (NBO) analyses. 相似文献
12.
Gloria Sánchez-Cabrera Francisco J. Zuno-Cruz María J. Rosales-Hoz 《Journal of organometallic chemistry》2007,692(11):2138-2147
The compound [Os3(CO)10(μ-Cl)(μ-AuPPh3)] (2) was prepared from the reaction between [Os3(CO)10(NCMe)2] (1) and [AuClPPh3] under mild conditions. The reaction of 2 with 4-mercaptopyridine (4-pyS) ligand yielded compounds [Os3(CO)10(μ-H)(μ-SC5H4N)] (4), formed by isolobal replacement of the fragment [AuPPh3]+ by H+ and [Os3(CO)10(μ-AuPPh3)(μ-SC5H4N)] (5). [Os3(CO)10(μ-H)(μ-SC5H4N)] (4) was also obtained by substitution of two acetonitrile ligands in the activated cluster 1 by 4-pyS, at room temperature in dichloromethane. Compounds 2-5 were characterized spectroscopically and the molecular structures of 4 and 5 in the solid state were obtained by single crystal X-ray diffraction studies. 相似文献
13.
Jamie L. Manson Tom Lancaster Stephen J. Blundell Yiming Qiu John Singleton Pinaki Sengupta Francis L. Pratt Jinhee Kang Changhoon Lee Myung-Hwan Whangbo 《Polyhedron》2010
The magnetic properties of α-Cu(dca)2(pyz) were examined by magnetic susceptibility, magnetization, inelastic neutron scattering (INS), muon-spin relaxation (μSR) measurements and by first-principles density functional theoretical (DFT) calculations and quantum Monte Carlo (QMC) simulations. The χ versus T curve shows a broad maximum at 3.5 K, and the data between 2 and 300 K is well described by an S = 1/2 Heisenberg uniform chain model with g = 2.152(1) and J/kB = −5.4(1) K. μSR measurements, conducted down to 0.02 K and as a function of longitudinal magnetic field, show no oscillations in the muon asymmetry function A(t). This evidence, together with the lack of spin wave formation as gleaned from INS data, suggests that no long-range magnetic order takes place in α-Cu(dca)2(pyz) down to the lowest measured temperatures. Electronic structure calculations further show that the spin exchange is significant only along the Cu–pyz–Cu chains, such that α-Cu(dca)2(pyz) can be described by a Heisenberg antiferromagnetic chain model. Further support for this comes from the M versus B curve, which is strongly concave owing to the reduced spin dimensionality. α-Cu(dca)2(pyz) is a molecular analogue of KCuF3 owing to dx2-y2 orbital ordering where nearest-neighbor magnetic orbital planes of the Cu2+ sites are orthogonal in the planes perpendicular to the Cu–pyz–Cu chains. 相似文献
14.
Fu-Chen Liu Tu-Chieh Tsai Chen-Shiang Lee Ju-Chun Wang 《Journal of organometallic chemistry》2010,695(3):423-4290
Mononuclear compounds M(CO)2(η3-C3H5)(en)(X) (X = Br, M = Mo(1), W(2); X = N3, M = Mo(3), W(4); X = CN, M = Mo(5), W(6)) and cyanide-bridged bimetallic compounds [(en)(η3-C3H5)(CO)2M(μ-CN)M(CO)2(η3-C3H5)(en)]Br (M = Mo (7), W(8)) were prepared and characterized. These compounds are fluxional and display broad unresolved proton NMR signals at room temperature. Compounds 1-6 were characterized by NMR spectroscopy at −60 °C, which revealed isomers in solution. The major isomers of 1-4 adopt an asymmetric endo-conformation, while those of 5 and 6 were both found to possess a symmetric endo-conformation. The single crystal X-ray structures of 1-6 are consistent with the structures of the major isomer in solution at low temperature. In contrast to mononuclear terminal cyanide compounds 5 and 6, cyanide-bridged compounds 7 and 8 were found to adopt the asymmetric endo-conformation in the solid state. 相似文献
15.
16.
The reaction of Cd(SePh)2 with CdX2 (X = Cl (1), Br (2)) in MeOH in the presence of PPh3 at 130 °C under solvothermal conditions affords the products [Cd4(SePh)7(PPh3)X]n, a one-dimensional assembly of adamantanoid [Cd4(SePh)6(PPh3)X] clusters joined into a polymeric chain by μ-SePh bridges. Compounds 1 and 2 represent examples of extended one-dimensional chains of closed ME (M = metal, E = S, Se, Te) systems, whose importance is based not only on their properties, but by their possible use as precursor materials for design and development of new methodologies via a “bottom up” strategy to obtain different clusters from single components. 相似文献
17.
Compounds M(CO)2(η3-C3H5)(L-L)(NCBH3) (L-L = dppe, M = Mo(1), W(2); L-L = bipy, M = Mo(3), W(4); L-L = en, M = Mo(5), W(6)) were prepared and characterized. The single crystal X-ray analyses of 2-6 revealed that the cyanotrihydroborate anion bonds to the metal through a nitrogen atom, the open face of the allyl group being pointed toward the two carbonyls (endo-isomer). In compounds 2, 5, and 6, the two donor atoms of the bidentate ligand occupy equatorial and axial positions, respectively. In the solid state structures of compounds 3 and 4 both nitrogen atoms of the bipy ligand occupy equatorial positions. The NMR spectroscopy reveals a fluxional behavior of compounds 1, 2, 5, and 6 in solution. Although the fluxional behavior of compounds 5 and 6 ceased at about −40 °C, that of compound 1 could not be stopped even at −90 °C. Their low temperature conformations are consistent with their solid state structures. Both the endo- and exo-isomers coexist in solution for compounds 3 and 4. 相似文献
18.
C. Sivasankar 《Journal of organometallic chemistry》2004,689(16):2726-2732
The reaction of [Cu3(dppm)3(μ3-OH)](ClO4)2 (1) with heterocumulenes (XCS; X = NPh, NMe and S) has been studied. The μ3-OH ligand inserts into PhNCS and MeNCS only in the presence of methanol. Insertion products are formed in accord with earlier observations made with copper(I)-aryloxides. On heating, the insertion products convert to a S bridged cluster [Cu4(dppm)4(μ4-S)](ClO4)2 (8), having a tetrameric core. However, in the reaction with CS2, 1 is converted to 8 even at room temperature in the presence of methanol. On the other hand, the dimeric complex [Cu2(dppm)2(CH3CN)4](ClO4)2, reacts with CS2 to give (diphenylphosphinomethyl)-diphenylphosphine sulfide, Ph2P-CH2-P(S)Ph2 (dppmS), which forms the complex [Cu(dppmS)2]ClO4 (9). A single crystal X-ray crystallographic study of 9, the first copper(I) complex of dppmS has been taken up to confirm the mono-oxidation of the dppm ligand and the nuclearity of the complex. Reactions of complex 1 with heterocumulenes and with elemental sulfur, are compared. 相似文献
19.
Fu-Chen Liu Shou-Chon Chen Shie-Ming Peng 《Journal of organometallic chemistry》2007,692(12):2375-2384
The effect that a solvent has on reactions of Cp2Zr{(μ-H)2BHR}2 and Cp2ZrH{(μ-H)2BHR} (R = CH3, Ph) with B(C6F5)3 has been studied. From the reaction in benzene the metathesis product Cp2Zr{(μ-H)2B(C6F5)2}2, 2, was isolated. In the case of diethyl ether, different hydride abstraction products, including [Cp2Zr(OEt2){(μ-H)2BHPh}][HB(C6F5)3], 3, [Cp2Zr(OEt2){(μ-H)2BHCH3}][HB(C6F5)3], 4, [Cp2Zr(OEt2){(μ-H)2BH2}][HB(C6F5)3], 5, and [Cp2Zr(OEt)(OEt2)][HB(C6F5)3], 6, were isolated depending on the starting zirconocene complex. The diethyl ether molecules of 3-6 are weakly coordinated to Zr and displaced in THF solution. Isolation of 3 and 4 is attributed to their fast precipitation from the reaction mixture, which prevented further reactions from occurring. In addition to the hydride abstraction, a hydride metathesis was also involved in the formation of 5. Time-elapsed 11B NMR studies indicate that 3 and 4 are the intermediates on the pathway to 5 and 6. The molecular structures of 2-6 were determined by single-crystal X-ray diffraction. 相似文献
20.
Shishir Ghosh Kaniz Fatema Md. Rafique Al-Mamun Graeme Hogarth 《Journal of organometallic chemistry》2011,696(18):2935-2942
Reaction of [Mn2(CO)9(NCMe)] with tetrahydropyrimidine-2-thione (thpymSH) at 25 °C furnishes the mono- and dinuclear complexes [Mn(CO)4(κ1:η1-SCNHC3H6NCO)] (2) and [Mn2(CO)6(μ-thpymS)2] (1), respectively. Carbon-nitrogen coupling is observed in compound 2 resulting in the formation of κ1:η1-SCNHC3H6NCO ligand while compound 1 adopts a centrosymmetric structure. Reaction of 1 with [Os3(CO)10(NCMe)2] at 80 °C affords the mixed Mn-Os cluster [MnOs3(CO)13(μ3-thpymS)] (3) which possesses a butterfly skeleton of four metal atoms whereas with Ru3(CO)12 at 110 °C gives the mixed Mn-Ru complex [MnRu3(CO)14(μ4-S)(κ1:η1-thpym)] (4). In contrast, treatment of 1 with Fe3(CO)12 at 80 °C furnishes two triiron complexes [Fe3(CO)9(μ3-S)(μ3-κ1:η1-C4H6N2)] (5) and [Fe3(CO)8(μ3-S)2(η1-C4H8N2)] (6). The former also results from the direct reaction of thpymSH with Fe3(CO)12 and reacts with H2S to afford 6. The molecular structures of all these new complexes have been determined by X-ray diffraction studies. 相似文献