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1.
Junes Ipaktschi Katja Reimann Michael Serafin Ansgar Dülmer 《Journal of organometallic chemistry》2003,670(1-2):66
Treatment of the η1-acetylide complex [(η5-C5H5)(CO)(NO)W---CC---C(CH3)3]Li (4) with 1,2-diiodoethane in THF at −78 °C, followed by the addition of Li---CC---R [R=C(CH3)3, C6H5, Si(CH3)3, 6a–6c] or n-C4H9Li and protonation with H2O, afforded the corresponding oxametallacyclopentadienyl complexes (η5-C5H5)W(I)(NO)[η2-O=C(CC---R)CH=CC(CH3)3] (7a–7c), 8c and (η5-C5H5)W(I)(NO)[η2-O=C(n-C4H9)CH=CC(CH3)3] (9). The formation of these metallafuran derivatives is rationalized by the electrophilic attack of 1,2-diiodoethane onto the metal center of 4 to form first the neutral complex [(η5-C5H5)(I)(CO)(NO)W---CC---C(CH3)3] (5). Subsequent nucleophilic addition of Li---CC---R 6a–6c or n-C4H9Li and a reductive elimination step followed by protonation leads to the products 7a–7c and 9. One reaction intermediate could be trapped with CF3SO3CH3 and characterized by a crystal structure analysis. The identity of another intermediate was established by infrared spectroscopic data. The oxametallacyclopentadienyl complex 10 forms in the presence of excess 1,2-diiodoethane through an alternative pathway and crystallizes as a clathrate containing iodine. 相似文献
2.
Reinhold Tacke Thomas Kornek Tilman Heinrich Christian Burschka Martin Penka Melanie Pülm Christine Keim Ernst Mutschler Günter Lambrecht 《Journal of organometallic chemistry》2001,640(1-2):140-165
The C/Si/Ge-analogous compounds rac-Ph(c-C5H9)El(CH2OH)CH2CH2NR2 (NR2=piperidino; El=C, rac-3a; El=Si, rac-3b; El=Ge, rac-3c) and (c-C5H9)2El(CH2OH)CH2CH2NR2 (NR2=piperidino; El=C, 5a; El=Si, 5b; El=Ge, 5c) were prepared in multi-step syntheses. The (R)- and (S)-enantiomers of 3a–c were obtained by resolution of the respective racemates using the antipodes of O,O′-dibenzoyltartaric acid (resolution of rac-3a), O,O′-di-p-toluoyltartaric acid (resolution of rac-3b), or 1,1′-binaphthyl-2,2′-diyl hydrogen phosphate (resolution of rac-3c). The enantiomeric purities of (R)-3a–c and (S)-3a–c were ≥98% ee (determined by 1H-NMR spectroscopy using a chiral solvating agent). Reaction of rac-3a–c, (R)-3a–c, (S)-3a–c, and 5a–c with methyl iodide gave the corresponding methylammonium iodides rac-4a–c, (R)-4a–c, (S)-4a–c, and 6a–c (3a–c→4a–c; 5a–c→6a–c). The absolute configuration of (S)-3a was determined by a single-crystal X-ray diffraction analysis of its (R,R)-O,O′-dibenzoyltartrate. The absolute configurations of the silicon analog (R)-4b and germanium analog (R)-4c were also determined by single-crystal X-ray diffraction. The chiroptical properties of the (R)- and (S)-enantiomers of 3a–c, 3a–c·HCl, and 4a–c were studied by ORD measurements. In addition, the C/Si/Ge analogs (R)-3a–c, (S)-3a–c, (R)-4a–c, (S)-4a–c, 5a–c, and 6a–c were studied for their affinities at recombinant human muscarinic M1, M2, M3, M4, and M5 receptors stably expressed in CHO-K1 cells (radioligand binding experiments with [3H]N-methylscopolamine as the radioligand). For reasons of comparison, the known C/Si/Ge analogs Ph2El(CH2OH)CH2CH2NR2 (NR2=piperidino; El=C, 7a; El=Si, 7b; El=Ge, 7c) and the corresponding methylammonium iodides 8a–c were included in these studies. According to these experiments, all the C/Si/Ge analogs behaved as simple competitive antagonists at M1–M5 receptors. The receptor subtype affinities of the individual carbon, silicon, and germanium analogs 3a–8a, 3b–8b, and 3c–8c were similar, indicating a strongly pronounced C/Si/Ge bioisosterism. The (R)-enantiomers (eutomers) of 3a–c and 4a–c exhibited higher affinities (up to 22.4 fold) for M1–M5 receptors than their corresponding (S)-antipodes (distomers), the stereoselectivity ratios being higher at M1, M3, M4, and M5 than at M2 receptors, and higher for the methylammonium compounds (4a–c) than for the amines (3a–c). With a few exceptions, compounds 5a–c, 6a–c, 7a–c, and 8a–c displayed lower affinities for M1–M5 receptors than the related (R)-enantiomers of 3a–c and 4a–c. The stereoselective interaction of the enantiomers of 3a–c and 4a–c with M1–M5 receptors is best explained in terms of opposite binding of the phenyl and cyclopentyl ring of the (R)- and (S)-enantiomers. The highest receptor subtype selectivity was observed for the germanium compound (R)-4c at M1/M2 receptors (12.9-fold). 相似文献
3.
Zia-ur-Rehman Niaz Muhammad Shaukat Shuja Saqib Ali Ian S. Butler Auke Meetsma Momin Khan 《Polyhedron》2009,28(16):3439-3448
Some new tri-, chlorodi- and diorganotin(IV) dithiocarboxylates (1–10) of 4-benzylpiperidine-1-carbodithioate ligand (L), with general formulae R3SnL {R = n-C4H9 (1), C6H11 (2), CH3 (3) and C6H5 (4)}, R2SnClL {R = n-C4H9 (5), C2H5 (7), CH3 (9)} and R2SnL2 {R = n-C4H9 (6), C2H5 (8), CH3 (10)}, have been synthesized by the reaction of organotin(IV) chlorides with the ligand-salt in the appropriate molar ratio. Elemental analysis, Raman, IR, multinuclear NMR (1H, 13C and 119Sn) and X-ray crystallographic studies have been undertaken to elucidate the structures of the complexes, both in solution and in solid state. Single-crystal X-ray diffraction study indicate trimeric, dimeric, supramolecular cyclic and supramolecular zig–zag chain structures for complexes 2, 4, 6 and 9, respectively. Square-pyramidal geometry is attributed to complex 9 on the basis of the τ value (0.4). A subsequent antimicrobial study indicates that the compounds are biologically active. 相似文献
4.
Stefan Kcher Bernhard Walfort Gerd Rheinwald Tobias Rüffer Heinrich Lang 《Journal of organometallic chemistry》2008,693(20):3213-3222
Alkyloxy- and aryloxy-functionalized titanocenes of type [Ti](Cl)(OR) (R = Me (2), CH2PPh2 (3), CH2Fc (4), C6H5 (5), C6H4-4-CN (6), C6H4-4-NO2 (7), C6H4-4-Me (8), C6H4-4-OMe (9), C6H4-4-C(O)Me (10), C6H4-4-CO2Me (11), C6H4-3-NO2 (12); [Ti] = (η5-C5H4SiMe3)2Ti; Fc = (η5-C5H4)(η5-C5H5)Fe) were synthesized by the reaction of [Ti]Cl2 (1) with ROH in a 1:1 molar ratio and in presence of Et2NH. Diaryloxy-titanocenes (e.g., [Ti](OC6H4-4-NO2)2 (13)) are accessible, when the ratio of 1 and ROH is changed to 1:2. This synthesis methodology also allowed the preparation of dinuclear complexes of composition ([Ti](Cl))2(μ-OC6H4O) (14) and ([Ti](Cl)(μ-OC6H4-4))2 (15) by the reaction of 1 with hydroquinone or 1,1′-dihydroxybiphenyl in a 2:1 stoichiometry.Cyclic voltammetric studies show the characteristic [Ti(IV)/Ti(III)] reductions. It was found that the potentials of the alkyloxy titanocenes 2–4 do not differ, while for the aryloxy-titanocenes 5–15 the reduction potentials correlate linearly with the σp/m Hammett substituent constants showing a strong influence of the substituents on the electron density at titanium.The structures of titanocenes 4, 5, 9, and 11–13 in the solid state are reported. Typical for these organometallic sandwich compounds is a distorted tetrahedral coordination geometry around titanium with D1–Ti–D2 angles (D1, D2 = centroids of the cyclopentadienyl ligands) of ca. 130 °. In comparison to FcCH2O-functionalized 4, for the aryloxy-titanocenes 5, 9, and 11–13 a significant larger Ti–O–C angle was found confirming electronic interactions between the titanium atom and the appropriate aryl group. 相似文献
5.
[C4H9)4N]2[Mo2O7] reacts with a variety of organic species containing α-diketone groups to give tetranuclear complexes of general composition [RMo4O15X]3−. The complexes [(C4H9)4N]3[(C9H4O)Mo4O15(OCH3)] (I), [(C4H9)4N]3[(C14H10)Mo4O15(C6H5CO2)] (11) and [(C4H9)4N]3[(C14H8)Mo4O15(OH)] (III) were synthesized from the reactions of dimolybdate with ninhydrin, benzil and phenanthraquinone, respectively. Complex II may also be prepared from dimolybdate and benzoin in acetonitrile-methanol solution, from which it co-crystallizes with the binuclear species [(C4H9)4N]2[Mo2O5(C6H5C(O)C(O)C6H5)2] · CH3CN · CH3OH (IV). Complexes I–III exhibit the tetranuclear core, previously described for the α-glyoxal derivatives [(C4H9)4N]3[(HCCH)Mo4O15X], where X = F− or HCO2−. The ligands may be formally described as diketals, formed by insertion of ligand carbonyl subunits into molybdenum-oxygen bonds. The structures I–III differ most dramatically in the identity and coordination mode of the anionic ligand X− which occupies a position opposite the diketal moiety relative to the [Mo4O11]2+ central cage. Thus, I exhibits a doubly bridging methoxy group in this position, while II possesses a benzoate ligand with an unusual μ3-O,O′coordination mode. Complex III presents a hydroxy-group unsymmetrically bonded to three of the molybdenum centres. The stereochemical consequences of the various coordination modes are discussed. Crystal data: Compound I, monoclinic space group Pc, a = 24.888(2), b = 12.897(3), c = 24.900(3) Å, β = 101.94(2)°, Dcalc = 1.28 g cm−1 for Z = 4. Structure solution and refinement based on 8695 reflections with Fo 6σ(Fo) (Mo-Kα, λ = 0.71073 Å) converged at a conventional discrepancy factor of 0.060. Compound II, orthorhombic space group Pbca, a = 20.426(6), b = 26.916(6), c = 32.147(7) Å, V = 17673.2(20) Å3, Dcalc = 1.33 g cm−3 for Z = 8; 5224 reflections, R = 0.076. Compound III, tetragonal space group I41/a, a = b = 48.129(6), c = 13.057(2) Å, V = 30246.2(12) Å3, Dcalc = 1.35 g cm−3 for Z = 16; 5554 reflections, R = 0.053. Compound IV, orthorhombic space group Pnca, a = 16.097(4), b = 16.755(4), c = 25.986(7) Å, V = 7008.1(13) Å3, Z = 4, Dcalc = 1.18 g cm−3 ; 2944 reflections, R = 0.061. 相似文献
6.
Kota Thirumala Prasad Gajendra Gupta Anna Venkateswara Rao Babulal Das Kollipara Mohan Rao 《Polyhedron》2009,28(13):2649-2654
The mononuclear complexes [(η6-arene)Ru(ata)Cl]PF6 {ata = 2-acetylthiazole azine; arene = C6H6 [(1)PF6]; p-iPrC6H4Me [(2)PF6]; C6Me6 [(3)PF6]}, [(η5-C5Me5)M(ata)]PF6 {M = Rh [(4)PF6]; Ir [(5)PF6]} and [(η5-Cp)Ru(PPh3)2Cl] {η5-Cp = η5-C5H5 [(6)PF6]; η5-C5Me5 (Cp*) [(7)PF6]; η5-C9H7 (indenyl); [(8)PF6]} have been synthesised from the reaction of 2-acetylthiazole azine (ata) and the corresponding dimers [(η6-arene)Ru(μ-Cl)Cl]2, [(η5-C5Me5)M(μ-Cl)Cl]2, and [(η5-Cp)Ru(PPh3)2Cl], respectively. In addition to these complexes a hydrolysed product (9)PF6, was isolated from complex (4)PF6 in the process of crystallization. All these complexes are isolated as hexafluorophosphate salts and characterized by IR, NMR, mass spectrometry and UV–Vis spectroscopy. The molecular structures of [2]PF6 and [9]PF6 have been established by single-crystal X-ray structure analyses. 相似文献
7.
Vinay K. Verma Ashish K. Asatkar Tripti A. Jain Santosh K. Tripathi Rajendra Singh Peter B. Hitchcock Siddhi Nigam Sushil K. Gupta 《Polyhedron》2009,28(13):2591-2598
Two new phenol based macroacyclic Schiff base ligands, 2,6-bis({N-[2-(phenylselenato)ethyl]}benzimidoyl)-4-methylphenol (bpebmpH, 1) and 2,6-bis({N-[3-(phenylselenato)propyl]}benzimidoyl)-4-methylphenol (bppbmpH, 2) of the Se2N2O type have been prepared by the condensation of 4-methyl-2,6-dibenzoylphenol (mdbpH) with the appropriate (for specific reactions) phenylselenato(alkyl)amine. These ligands with Cu(II) acetate monohydrate in a 2:1 molar ratio in methanol form complexes of the composition [(C6H2(O)(CH3){(C6H5)CN(CH2)nSe(C6H5)}{(C6H5)CO}2Cu] (3 (n = 2), 4 (n = 3)) with the loss of phenylselenato(alkyl)amine and acetic acid. In both these complexes, one arm of the ligand molecule undergoes hydrolysis, and links with Cu(II) in a bidentate (NO) fashion, as confirmed by single crystal X-ray crystallography of complex 3. The selenium atoms do not form part of the copper(II) distorted square planar coordination sphere which has a trans-CuN2O2 core. The average Cu–N and Cu–O distances are, respectively, 1.973(3) and 1.898(2) Å. The N–Cu–N and O–Cu–O angles are, respectively, 167.4(11)° and 164.5(12)°. The compounds 1–4 have been characterized by elemental analysis, conductivity measurements, mass spectrometry, IR, electronic, 1H and 77Se{1H} NMR spectroscopy and cyclic voltammetry. The interaction of complex 3 with calf thymus DNA has been investigated by a spectrophotometric method and cyclic voltammetry. 相似文献
8.
Maheswaran Hariharasarma Charles H. Lake Charles L. Watkins Gary M. Gray 《Journal of organometallic chemistry》1999,580(2):1541
Chlorodiphenylphosphine and 2,2′-biphenylylenephosphorochloridite react with 2-hydroxy-2′-(1,4-bisoxo-6-hexanol)-1,1′-biphenyl to yield the new α,ω-bis(phosphorus-donor)-polyether ligands, 2-Ph2PO(CH2CH2O)2–C12H8-2′-OPPh2 (1) and 2-(2,2′-O2C12H8)P(CH2CH2O)2–C12H8-2′-P(2,2′-O2C12H8) (2). These ligands react with Mo(CO)4(nbd) to form the monomeric metallacrown ethers, cis-Mo(CO)4{2-Ph2PO(CH2CH2O)2–C12H8-2′-OPPh2} (cis-3) and cis-Mo(CO)4{2-(2,2′-O2C12H8)P(CH2CH2O)2–C12H8-2′-P(2,2′-O2C12H8)} (cis-4), in good yields. The X-ray crystal structures of cis-3 and cis-4 are significantly different, especially in the conformation of the metal center and the adjacent ethylene group. The very different 13C-NMR coordination chemical shifts of this ethylene group in cis-3 and cis-4 suggest that the solution conformations of these metallacrown ethers are also quite different. Both metallacrown ethers undergo cis–trans isomerization in the presence of HgCl2. Although the cis–trans equilibrium constants for the isomerization reactions are nearly identical, the isomerization of cis-3 is more rapid. Phenyl lithium reacts with cis-3 to form the corresponding benzoyl complexes but does not react with either trans-3 or cis-4. Both the slower rate of cis–trans isomerization of cis-4 and its lack of reaction with PhLi are consistent with weaker interactions between the hard metal cations and the carbonyl oxygens in both trans-3 and cis-4. 相似文献
9.
Nguyen Thuy Ba Linh Nguyen Thi Dieu Huyen Seok Kyun Noh Won Seok Lyoo Dong-Ho Lee Yongman Kim 《Journal of organometallic chemistry》2009,694(21):3438-3443
Half-titanocene is well-known as an excellent catalyst for the preparation of SPS (syndiotactic polystyrene) when activated with methylaluminoxane (MAO). Dinuclear half-sandwich complexes of titanium bearing a xylene bridge, (TiCl2L)2{(μ-η5, η5-C5H4-ortho-(CH2–C6H4–CH2)C5H4}, (4 (L = Cl), 7 (L = O-2,6-iPr2C6H3)) and (TiCl2L)2{(μ-η5, η5-C5H4-meta-(CH2–C6H4–CH2)C5H4} (5 (L = Cl), 8(L = O-2,6-iPr2C6H3)), have been successfully synthesized and introduced for styrene polymerization. The catalysts were characterized by 1H- and 13C NMR, and elemental analysis. These catalysts were found to be effective in forming SPS in combination with MAO. The activities of the catalysts with rigid ortho- and meta-xylene bridges were higher than those of catalysts with flexible pentamethylene bridges. The catalytic activity of four dinuclear half-titanocenes increased in the order of 4 < 5 < 7 < 8. This result displays that the meta-xylene bridged catalyst is more active than the ortho-xylene bridged and that the aryloxo group at the titanium center is more effective at promoting catalyst activity compared to the chloride group at the titanium center. Temperature and ratio of [Al]:[Ti] had significant effects on catalytic activity. Polymerizations were conducted at three different temperatures (25, 40, and 70 °C) with variation in the [Al]:[Ti] ratio from 2000 to 4000. It was observed that activity of the catalysts increased with increasing temperature, as well as higher [Al]:[Ti]. Different xylene linkage patterns (ortho and meta) were recognized to be a principal factor leading to the characteristics of the dinuclear catalyst due to its different spatial arrangement, causing dissimilar intramolecular interactions between the two active sites. 相似文献
10.
Irene Ara Jesús R. Berenguer Eduardo Eguizbal Juan Fornis Julio Gmez Elena Lalinde 《Journal of organometallic chemistry》2003,670(1-2):221-234
The novel hexanuclear platinum–copper complex [Pt2Cu4(C6F5)4(CCtBu)4(acetone)2] (1) and the polynuclear derivative [PtCu2(C6F5)2(CCPh)2]x (2), which crystallises in acetone as [Pt2Cu4(C6F5)4(CCPh)4(acetone)4] (2)·(acetone)4, have been prepared using [cis-Pt(C6F5)2(THF)2] and the corresponding copper–acetylide [Cu(CCR)]x (molar ratio 1:2) as starting materials. Treatment of 1 and 2 with 2,2′-bipyridine (molar ratio Cu–bipy 1:1), afforded the new trinuclear derivatives [{cis-Pt(C6F5)2(μ-CCR)2}{Cu(bipy)}2] (R=tBu 3, Ph 4), in which the dianionic 3-platina-1,4-diyne acts as a didentate bridging ligand to two different cationic Cu(bipy) units through η2-side-on coordination of the alkynyl fragments. While similar treatment of 1 with dppe (Cu–dppe 1:1) yielded [{cis-Pt(C6F5)2(μ-CCtBu)2}{Cu(dppe)}2] (5), the analogous reaction of 2 with dppe afforded a mixture of complexes containing [Pt(C6F5)(CCPh)(dppe)] as the main platinum compound. The crystal structures of 1, 2·(acetone)4, 3 and 4 and the luminescent behaviour of all complexes have been determined. A comparison of the photoluminescent spectra of 1 and 2 with those of the related platinum–silver species [PtAg2(C6F5)2(CCR)2]x and the monomeric [cis-Pt(C6F5)2(CCR)2]2− suggests the presence of emitting states bearing a large cluster [PtM2]x-to-ligand (alkynide) charge transfer (CLCT). 相似文献
11.
REDOR technique was applied to natural abundance 13C nuclei coupled to a singly labeled 15N nucleus to determine the 13C, 15N interatomic distances simultaneously in crystalline ammonium [15N]
-glutamate monohydrate (1). Consequently, the interatomic C–N distances between 15N and 13C=O, 13Cα, 13Cβ, 13Cγ, and 13Cδ carbon nuclei for 1 were determined with a precision of ±0.15 Å, after the experimental conditions such as the location of samples in the rotor, length of π pulse etc. were carefully optimized. 13C-REDOR factors for three spin system, (ΔS/S0)CN1N2, and the sum of two isolated 2-spin system, (ΔS/S0)*=(ΔS/S0)CN1+(ΔS/S0)CN2, were further evaluated by the REDOR measurements on isotopically diluted 1 in a controlled manner. Subsequently, the intra- and intermolecular C–N distances were separated by searching the minima in the contour map of root mean square deviation (RMSD) between the theoretically and experimentally obtained (ΔS/S0)* values against two interatomic distances, rC–N1 and rC–N2. When the intramolecular C–N distance (rC–N1) of the particular carbon nucleus is substantially shorter than the intermolecular one (rC–N2), C–N distances within a single molecule were obtained with an accuracy of ±0.06 Å as in the cases of C=O, Cα and Cβ carbon nuclei. C–N distances between the molecule in question and the nearest neighboring molecules can be also obtained, although accuracy was lower. On the contrary, it was difficult to determine the interatomic distances in the same molecule when the intermolecular dipolar contribution is larger than the intramolecular one as in the case of Cδ carbon nucleus. 相似文献
12.
John E Davies Brian F.G Johnson Caroline M Martin Ruth H.H Pearson Paul J Dyson 《Journal of organometallic chemistry》1998,550(1-2)
Ligands containing unsaturated C2 and C4 units have been reacted with triruthenium dodecacarbonyl to produce new organometallic clusters with simple closo-RuxCy polyhedral frameworks which may be regarded as quasi-carboranes. The thermolysis of [Ru3(CO)12] with 1,4-diphenybutadiene yields the new clusters [Ru3(CO)8(μ3-CPh(CH)2CPh)] 2 and [Ru4(CO)9(μ4-CPhCCH2CH2Ph)] 3, while treatmentof a solution of [Ru3(CO)12] and diphenylacetylene with trimethylamine N–oxide (Me3NO) yields [Ru2(CO)6(μ-{C2Ph2}2CO)] 4 as the major product and the new cluster [Ru4(CO)11(μ4-C2Ph2)2] 5. The solid-state structures of 2, 3 and 5 have been established by single crystal X-ray diffraction analyses and are shown to possess closo-Ru3C4 pentagonal bipyramidal, closo-Ru4C2 octahedral and closo-Ru4C4 dodecahedral skeletons, respectively. The structure and bonding in all three clusters may be rationalised using the Wade–Mingos polyhedral skeletal electron pair approach. 相似文献
13.
Partha Mukherjee Shrabanti Bhattacharya Sandip K. Nayak Subrata Chattopadhyay Sumanta Bhattacharya 《Chemical physics》2009,360(1-3):116-122
A detailed UV–Vis spectrometric and thermodynamic studies were done to look insight into the nature of molecular interactions of the electron donor–acceptor complexes of C60 and C70 with 5,10,15,20-tetrakis(octadecyloxyphenyl)-21H,23H-porphyrin (1) in chloroform and toluene. Charge transfer (CT) absorption bands were located in the visible region and vertical ionization potential of 1 was determined utilizing CT transition energy. Low values of oscillator and transition dipole strengths suggested that the complexes were almost of neutral character in ground states. The high binding constant value for the C70–1 complex indicated high selectivity of 1 molecule towards C70. Experimental as well as theoretically determined of enthalpies of formation value substantiated the trend in K values for fullerene–1 complexes. 相似文献
14.
Kentaro Yamane Satoko Hayashi Waro Nakanishi Takahiro Sasamori Norihiro Tokitoh 《Polyhedron》2008,27(18):3557-3566
8-G-1-(p-YC6H4CCSe)C10H6 [2 (G = Cl) and 3 (G = Br): Y = H (a), OMe (b), Me (c), F (d), Cl (e), CN (f) and NO2 (g)] have been prepared and the NMR spectra measured, in addition to 1 (G = H). Structures have been determined by X-ray crystallographic analysis for 2b, 2e and 2g, which are all type B (B), where the Se–Csp bond is placed in the naphthyl plane in B. The type is classified as A if the Se–Csp bond is perpendicular to the naphthyl plane. Structures around the p-YC6H4 (Ar) group are pd (perpendicular) for Y = OMe (2b) and Cl (2e) and pl (planar) for Y = NO2 (2g), where the Se–CNap bond is placed in the aryl plane in pl and perpendicular to the plane in pd. The 1b (A: pd) structure changes dramatically on going to 2b (B: pd) with G = Cl at the 8-position. The effect is called the G-dependence in 2. The G-dependence arises from the energy lowering effect of the np(Cl)σ*(Se–Csp) 3c–4e interaction. Structures are both (B: pd) for 1e and 2e and both (B: pl) for 1g and 2g. One may realize that the structures are unchanged by G = Cl in place of G = H for Y = Cl and NO2 at a first glance. However, the B structures in 2e and 2g must be much more stabilized by the G-dependence of the np(Cl)σ*(Se–Csp) 3c–4e interaction or the GSe–Csp–Csp–Csp2 5c–6e type interaction. The structures of 2 and 3 are examined in solution based on the NMR parameters. The results show that 2 and 3 behave very similarly to each other and the structures are predominantly B, with some equilibrium between pd and pl around the aryl groups in solution. Quantum chemical calculations support the observations. 相似文献
15.
Copper(II) coordination compounds with ferulic acid 总被引:1,自引:0,他引:1
The first two molecular structures of the ferulic acid (3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid, C10H10O4) coordination compounds are presented, namely, [Cu2(C10H9O4)4(CH3CN)2] 1 and [Cu2(C10H9O4)4(C6H6N2O)2]·4CH3CN (C6H6N2O = nicotinamide) 2. Both compounds were synthesised from the starting mixture of Cu2O and CuCl upon copper oxidation in the acetonitrile solution. The single-crystal X-ray diffraction analysis of 1 and 2 reveals the binuclear structure of the ‘paddle–wheel’ type for both complexes. 1 and 2 are unstable outside mother liquid due to loosely bound acetonitrile molecules. The final products of decomposition are [Cu2(C10H9O4)4] 1a and [Cu2(C10H9O4)4(C6H6N2O)2] 2a, which were characterized by several physico-chemical methods. The triplet X-band EPR spectra of 1a and 2a, showing signals BZ1 15 mT, B2 460 mT and BZ2 580 mT, are in agreement with the expected data for the binuclear tetracarboxylate units, found in the structures of the parent complexes 1 and 2. Together with the room temperature magnetic susceptibility data, μeff/B.M. 1.40 (1a), 1.48 (2a), the EPR spectra analysis confirm the antiferromagnetic interaction in 1a and 2a. This is suggesting preservation and stability of the paddle–wheel structures in 1a and 2a. 相似文献
16.
Geoffrey R. County Ron S. Dickson Susan M. Jenkins Julian Johnson Olga Paravagna 《Journal of organometallic chemistry》1997,530(1-2)
Treatment of (η5-C5H5)2Rh2(CO)η1-Ph2P(CH2)n PPh2(μ-η1:η1-CF3C2CF3) (I) with (η5-CH3C5H4)Mn(CO)2(thf) or Cr(CO)5(thf) gives the hetero-trinuclear products (η-C5H5)2Rh2(CO)(μ-CF3C2CF3)μ:η1:η1-Ph2P(CH2)nPPh2(η-CH3C5H3C4)Mn(CO2) (II, n = 1–4) and (η5-C5H5)2Rh2(CO)(μ-CF3C2CF3)μ:η1:η1-Ph2P(CH2)nPPh2Cr(CO)5 (IV, n = 1–4) in good yields. In these products, the configuration of the CO and bisphosphine units on the Rh-Rh bond is trans. Related reactions between (η5:η5-C5H4CH2C5H4)Rh2(CO)η1-Ph2P(CH2)nPPh2(μ-η1:η1- (V) and the same solvated manganese and chromium complexes give (η5:η5-C5H4CH2C5H4)Rh2(CO)(μ-CF3C2CF3)μ:η1:η1-Ph2P(CH2) (VI, n = 1, 2 or 4) and (η5:η5-C5H4CH2C5H4)Rh2(CO)(μ-CF3C2CF3)μ:η1:η1-Ph2P(CH2) (VIII). The complexes (VI) and (VIII) have a mutually cis arrangement of CO and the bisphosphine on the Rh-Rh bond. Attempts to induce the complexes (IV), (V), (VI), and (VIII) to form clusters by loss of CO and Rh-M bond formation were not successful. Treatment with trimethylamine oxide or sunlight irradiation generally resulted in loss of the hetero-metal and formation of the dirhodium phosphine oxide complexes (III, n = 2 or 4) and (VII, n = 2, 3). 相似文献
17.
Tsun-Hung Hsiao Tzu-Liang Wu Sandipan Chatterjee Chin-Yi Chiu Hon Man Lee Lorenzo Bettucci Claudio Bianchini Werner Oberhauser 《Journal of organometallic chemistry》2009,694(25):4014-4024
The imidazolium salts 1,1′-dibenzyl-3,3′-propylenediimidazolium dichloride and 1,1′-bis(1-naphthalenemethyl)-3,3′-propylenediimidazolium dichloride have been synthesized and transformed into the corresponding bis(NHC) ligands 1,1′-dibenzyl-3,3′-propylenediimidazol-2-ylidene (L1) and 1,1′-bis(1-naphthalenemethyl)-3,3′-propylenediimidazol-2-ylidene (L2) that have been employed to stabilize the PdII complexes PdCl2(κ2-C,C-L1) (2a) and PdCl2(κ2-C,C-L2) (2b). Both latter complexes together with their known homologous counterparts PdCl2(κ2-C,C-L3) (1a) (L3 = 1,1′-dibenzyl-3,3′-ethylenediimidazol-2-ylidene) and PdCl2(κ2-C,C-L4) (1b) (L4 = 1,1′-bis(1-naphthalenemethyl)-3,3′-ethylenediimidazol-2-ylidene) have been straightforwardly converted into the corresponding palladium acetate compounds Pd(κ1-O-OAc)2(κ2-C,C-L3) (3a) (OAc = acetate), Pd(κ1-O-OAc)2(κ2-C,C-L4) (3b), Pd(κ1-O-OAc)2(κ2-C,C-L1) (4a), and Pd(κ1-O-OAc)2(κ2-C,C-L2) (4b). In addition, the phosphanyl-NHC-modified palladium acetate complex Pd(κ1-O-OAc)2 (κ2-P,C-L5) (6) (L5 = 1-((2-diphenylphosphanyl)methylphenyl)-3-methyl-imidazol-2-ylidene) has been synthesized from corresponding palladium iodide complex PdI2(κ2-P,C-L5) (5). The reaction of the former complex with p-toluenesulfonic acid (p-TsOH) gave the corresponding bis-tosylate complex Pd(OTs)2(κ2-P,C-L5) (7). All new complexes have been characterized by multinuclear NMR spectroscopy and elemental analyses. In addition the solid-state structures of 1b·DMF, 2b·2DMF, 3a, 3b·DMF, 4a, 4b, and 6·CHCl3·2H2O have been determined by single crystal X-ray structure analyses. The palladium acetate complexes 3a/b, 4a/b, and 6 have been employed to catalyze the oxidative homocoupling reaction of terminal alkynes in acetonitrile chemoselectively yielding the corresponding 1,4-di-substituted 1,3-diyne in the presence of p-benzoquinone (BQ). The highest catalytic activity in the presence of BQ has been obtained with 6, while within the series of palladium-bis(NHC) complexes, 4b, featured with a n-propylene-bridge and the bulky N-1-naphthalenemethyl substituents, revealed as the most active compound. Hence, this latter precursor has been employed for analogous coupling reaction carried out in the presence of air pressure instead of BQ, yielding lower substrate conversion when compared to reaction performed in the presence of BQ. The important role of the ancillary ligand acetate in the course of the catalytic coupling reaction has been proved by variable-temperature NMR studies carried out with 6 and 7′ under catalytic reaction conditions. 相似文献
18.
Dipak Kumar Dutta J. Derek Woollins Alexandra M.Z. Slawin Amy L. Fuller Biswajit Deb Podma Pollov Sarmah Madan Gopal Pathak Dilip Konwar 《Journal of molecular catalysis. A, Chemical》2009,313(1-2):100-106
The reaction of dimeric rhodium precursor [Rh(CO)2Cl]2 with two molar equivalent of 1,1,1-tris(diphenylphosphinomethyl)ethane trichalcogenide ligands, [CH3C(CH2P(X)Ph2)3](L), where X = O(a), S(b) and Se(c) affords the complexes of the type [Rh(CO)2Cl(L)] (1a–1c). The complexes 1a–1c have been characterized by elemental analyses, mass spectrometry, IR and NMR (1H, 31P and 13C) spectroscopy and the ligands a–c are structurally determined by single crystal X-ray diffraction. 1a–1c undergo oxidative addition (OA) reactions with different electrophiles such as CH3I, C2H5I and C6H5CH2Cl to give Rh(III) complexes of the types [Rh(CO)(COR)ClXL] {R = –CH3 (2a–2c), –C2H5 (3a–3c); X = I and R = –CH2C6H5 (4a–4c); X = Cl}. Kinetic data for the reaction of a–c with CH3I indicate a first-order reaction. The catalytic activity of 1a–1c for the carbonylation of methanol to acetic acid and its ester is evaluated and a higher turn over number (TON = 1564–1723) is obtained compared to that of the well-known commercial species [Rh(CO)2I2]− (TON = 1000) under the reaction conditions: temperature 130 ± 2 °C, pressure 30 ± 2 bar and time 1 h. 相似文献
19.
Xin Zhou Qing-Jiang Pan Tao Liu Ming-Xia Li Hong-Xing Zhang 《Journal of Molecular Structure》2008,863(1-3):91-98
A comprehensive calculations were carried out to get a deep insight into the ground- and excited-state electronic structures and the spectroscopic properties for a series of [Pt(4-X–trpy)CCC6H4R]+ complexes (trpy = 2,2′,6′,2″-terpyridine; X = H, R = NO2 (1), Cl (2), C6H5 (3) and CH3 (4); R = Cl, X = CH3 (5) and C6H5 (6)). MP2 (second-order Møller–Plesset perturbation) and CIS (single-excitation configuration interaction) methods were employed to optimize the structures of 1–6 in the ground and excited states, respectively. The investigation showed that substituted phenylacetylide and trpy ligands only give rise to a small variation in geometrical structures but lead to a sizable difference in the electronic structures for 1–6 in the ground and excited states. The introduction of electron-rich groups into the phenylacetylide and/or terpyridyl ligands produces two different low-lying absorptions for 1 and 2–6, i.e., Pt(5d) → π*(trpy) metal-to-ligand charge transfer (MLCT) mixed with π → π*(CCPh) intraligand charge transfer (ILCT) for 1 and Pt(5d)/π(CCPh) → π*(trpy) charge transfer (MLCT and LLCT) for 2–6. Remarkable electronic resonance on the whole Pt–CCPh–NO2 moiety for 1 may be responsible for the difference. Solvatochromism calculation revealed that only LLCT/MLCT transitions showed the solvent dependence, consistent with the experimental observations. 相似文献
20.
A set of oxygen-containing molybdenum oxide clusters Mo
x
O
y
(x = 1–3; y = 1–9) was obtained with the use of a combination of a Knudsen cell and an ion trap cell. The reactions of positively charged clusters with C1–C4 alcohols were studied using ion cyclotron resonance. The formation of a number of organometallic ions, the products of initial insertion of molybdenum oxide ions into the C–O and C–H bonds of alcohols, and polycondensation products of methanol and ethanol were found. The reactions of neutral molybdenum oxide clusters Mo
x
O
y
(x = 1–3; y = 1–9) with protonated C1–C4 alcohols and an ammonium ion were studied. The following limits of proton affinity (PA) were found for neutral oxygen-containing molybdenum clusters: (MoO) < 180, (Mo2O4, Mo2O5, and Mo3O8) = 188 ± 8, PA(MoO2) = 202 ± 5, PA(MoO3, Mo2O6, and Mo3O9) > 207 kcal/mol. 相似文献