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1.
The bis(N,N′-diisopropylbenzimidazolin-2-ylidene)Pd(II) complexes trans-[PdBr2(iPr2-bimy)2] (trans-1) and trans-[PdI2(iPr2-bimy)2] (trans-2) have been prepared in good yields by in situ deprotonation of the corresponding N,N′-diisopropylbenzimidazolium salt (iPr2-bimyH+X−) (A: X = Br, B: X = I) with Pd(OAc)2 in DMSO at elevated temperature. Salt metathesis of trans-1 or trans-2 with AgO2CCF3 in refluxing CH3CN afforded the novel mixed carbene-carboxylato complex cis-[Pd(O2CCF3)2(iPr2-bimy)2] (cis-3). This halo/trifluorocarboxylato ligand substitution can be regarded as a selective method for the synthesis of cis-configured bis(carbene) complexes. All compounds have been fully characterized by multinuclei NMR spectroscopies and ESI mass spectrometry. X-ray diffraction studies on single crystals of trans-1, trans-2 and cis-3 revealed a square planar geometry and a fixed orientation of the N-isopropyl substituents with the C-H protons pointing to the metal center to maximize rare C-H?Pd preagostic interactions. These interactions are also retained in solution as indicated by the large downfield shift of the isopropyl C-H protons in the 1H NMR spectrum compared to those in precursor salts A or B. A preliminary catalytic study revealed that all complexes are highly active in the Mizoroki-Heck coupling of aryl bromides and chlorides. However, these complexes gave slower conversions as compared to catalysts with less bulky benzimidazolin-2-ylidenes. This is most likely due to the steric bulk of the ligands, which hamper a fast reductive formation of catalytically active Pd(0) species. 相似文献
2.
Petr Štěpni?ka Martin Krupa Martin Lama? Ivana Císa?ová 《Journal of organometallic chemistry》2009,694(18):2987-738
Amide coupling between [2-(diphenylphosphino)phenyl]methylamine and 1′-(diphenylphosphino)ferrocene-1-carboxylic acid (Hdpf) afforded a novel diphosphine-amide, 1-{N-[(2-(diphenylphosphino)phenyl)methyl]carbamoyl}-1′-(diphenylphosphino)ferrocene (1), which was subsequently studied as a ligand for palladium(II) complexes. Depending on the metal precursor, the following complexes were isolated: [PdCl2(1-κ2P,P′)] (2), [PdCl(Me)(1-κ2P,P′)] (3), [(μ-1){PdCl2(PBu3)}2] (4) and [(μ-1){PdCl(LNC)}2] (LNC = 2-[(dimethylamino-κN)methyl]phenyl-κC1), featuring this ligand either as a trans-chelating or as a P,P′-bridging donor. The crystal structure of 2·1.25CH2Cl2 was established by X-ray crystallography, corroborating that 1 coordinates as a trans-spanning diphosphine without any significant distortion to the coordination sphere. Complex 2 together with a catalyst prepared in situ from 1 and palladium(II) acetate were tested in Suzuki-Miyaura reaction of aryl bromides with phenylboronic acid in dioxane. 相似文献
3.
A series of palladium(II) complexes (1-6) bearing cis-chelating homo-dicarbene ligands with varying alkyl bridges (C1-C3) and N-heterocyclic backbones (imidazole and benzimidazole) have been synthesized by reaction of Pd(OAc)2 with the respective diazolium bromides (A·2HBr - F·2HBr) in DMSO. A comparative catalytic study employing aryl chlorides in the Mizoroki-Heck reaction revealed the superiority of methylene- and propylene-bridged dibenzimidazolin-2-ylidenes over their imidazole-derived analogues. Based on these results, two new propylene-bridged hetero-dicarbene complexes (7 and 8) were designed containing a mixed benzimidazole/imidazole-derived NHC-donor set. Notably, both complexes outperformed their homo-dicarbene analogues, which may be due to the electronic asymmetry induced by hetero-dicarbene ligands. The molecular structures of complex 6 and 8 are also presented. 相似文献
4.
?lkay Çayl?Güne? Süheyla Kürkçüo?lu Okan Zafer Ye?ilelOnur ?ahin Orhan Büyükgüngör 《Polyhedron》2012,31(1):386-394
Three new heterometallic complexes, [Cu(N-Meim)4Pd(μ-CN)2(CN)2]n (1), [Zn(N-Meim)3Pd(μ-CN)2(CN)2]n (2) and [Cd(N-Meim)2Pd(μ-CN)4]n (3), have been isolated from the reactions of M[Pd(CN)4] (M = Cu(II), Zn(II) or Cd(II)) and N-Meim (N-methylimidazole) with in different molar ratios. All complexes have been characterized by X-ray analyses, vibrational (FT-IR and Raman) spectra, thermal and elemental analyses. The crystallographic analysis reveals that the crystal structures of 1 and 2 are 1D coordination polymer, while 3 presents a 2D network. In the Cu(II) and Zn(II) complexes, two cyanide groups of [Pd(CN)4]2− coordinated to the adjacent M(II) ions and distorted octahedral and square pyramidal geometries of complexes are completed by four and three nitrogen atoms of N-Meim ligands, respectively. The Cd(II) ion is six-coordinate, completed with the two nitrogen atoms of N-Meim ligands in the axial positions and the four nitrogen atoms from bridging cyano groups in the equatorial plane. The most striking features of complexes 1-3 are the presence of obvious C-H?Pd hydrogen-bonding interactions between the Pd(II) and hydrogen atoms of N-Meim ligand. This weak hydrogen bonding plays a crucial role in the architecture of the network polymers. The adjacent chains are held together by C-H?Pd, C-H?π or π?π interactions, forming three-dimensional network. 相似文献
5.
Osman Akba Feyyaz Durap Ak?n Baysal Saim Özkar 《Journal of organometallic chemistry》2009,694(5):731-18
Oxidation of N,N,N′,N′-tetrakis(diphenylphosphino)ethylendiamine (1) with elemental sulfur and selenium gives the corresponding sulfide and selenide, respectively, [(Ph2P(E))2NCH2CH2N(P(E)Ph2)2] (E: S 1a, Se 1b). Complexes of 1 [(M2Cl4){(Ph2P)2NCH2CH2N(PPh2)2}] (M: Ni(II) 1c, Pd(II) 1d, Pt(II) 1e) were prepared by the reaction of 1 with NiCl2 or [MCl2(COD)] (M = Pd, Pt). The new compounds were characterized by NMR, IR spectroscopy and elemental analysis. The catalytic activity of Pd(II) complex 1d was tested in the Suzuki coupling reaction and Heck reaction. The palladium complex 1d catalyses the Heck reaction between styrene and aryl bromides as well as Suzuki coupling reaction between phenylboronic acid and arylbromides affording stilbenes and biphenyls in high yield, respectively. 相似文献
6.
Yuan Han 《Journal of organometallic chemistry》2008,693(19):3159-3165
Reaction of the sterically bulky 1,3-dibenzhydrylbenzimidazolium bromide (Bh2-bimyH+Br−) (A) with Pd(OAc)2 in DMSO yielded a mono(carbene) Pd(II) complex 1 with a N-bound benzimidazole derivative, which resulted from an unusual NHC rearrangement reaction. Reaction of A with Ag2O, on the other hand, cleanly gave the Ag(I) carbene complex [AgBr(Bh2-bimy)] (2), which has been used as a carbene-transfer agent to prepare the acetonitrile complex trans-[PdBr2(CH3CN)(Bh2-bimy)] (3). Dissociation of acetonitrile from complex 3 and subsequent dimerization afforded the dinuclear Pd(II) complex [PdBr2(Bh2-bimy)]2 (4) in quantitative yield. All complexes were fully characterized by multinuclear NMR spectroscopies, ESI mass spectrometry and X-ray diffraction analysis. Furthermore, the catalytic activity of complex 4 in aqueous Suzuki-Miyaura cross-coupling reactions was studied and compared with that of its previously reported less bulky analogue [PdBr2(iPr2-bimy)]2. 相似文献
7.
Freddy Tjosaas 《Journal of organometallic chemistry》2007,692(24):5429-5439
Palladium complexes of N-phenyl-2-pyridylamine (4) and dipyridylamine substrates (7, 11) have been studied. Due to the coordination ability of the pyridine-nitrogen atoms, the pyridyl substrates, 4, 7, 11 were subjected to Pd(OAc)2 complexations and a number of N-aryl-2-pyridylamine Pd complexes (13-17) were isolated and characterised, in particular by NMR and ESI-MS. A new method for the preparation of the acetato-bridged six-membered ring palladacycle complex (13) of 4 is reported. The dipyridyl amines 7, 11 formed cis/trans bis-dentate acetato-bridged dimeric Pd2Lig2(OAc)2 (14a,b/16a,b) and Pd3Lig2(OAc)4 complexes (15a,b/17a,b). The N-aryl-2-pyridylamine substrates (4, 7, 11) were prepared by oxidative nucleophilic substitution, by 1,3-cycloaddition reaction or by Buchwald amination. 相似文献
8.
Hiroyuki Kawaguchi 《Tetrahedron》2006,62(47):10907-10913
5-(N-Bromo)iminothianthrene (2) and 5-(N-bromo)iminothianthrene 10-oxide (5) and 10,10-dioxide (8) were prepared and their alkaline hydrolyses were studied. The compound 2 and cis-5-(N-bromo)iminothianthrene 10-oxide (cis-5) afforded the corresponding sulfoximine exclusively. While, unexpectedly, both trans-5-(N-bromo)iminothianthrene 10-oxide (trans-5) and 8 afforded mainly de-brominated products, trans-5-iminothianthrene 10-oxide (trans-4) and 5-iminothianthrene 10,10-dioxide (7), respectively. In these cases, 5-iminothianthrene 5,10-dioxide (6) (Z- and E-mixture) and 5-iminothianthrene 5,10,10-trioxide (9) and further de-iminated products were also formed respectively as minor products. The stereochemical considerations on the SN reactions are described in view of the steric effect and ‘flip-flap’ motion of the thianthrene framework. 相似文献
9.
Schiff base N,N′-bis(salicylidene)-p-phenylenediamine (LH2) complexed with Pt(en)Cl2 and Pd(en)Cl2 provided [Pt(en)L]2 · 4PF6 (1) and Pd(Salen) (2) (Salen = N,N′-bis(salicylidene)-ethylenediamine), respectively, which were characterized by their elemental analysis, spectroscopic data and X-ray data. A solid complex obtained by the reaction of hexafluorobenzene (hfb) with the representative complex 1 has been isolated and characterized as 3 (1 · hfb) using UV–Vis, NMR (1H, 13C and 19F) data. A solid complex of hfb with a reported Zn-cyclophane 4 has also been prepared and characterized 5 (4 · hfb) for comparison with complex 3. The association of hfb with 1 and 4 has also been monitored using UV–Vis and luminescence data. 相似文献
10.
Sunirban Das 《Journal of organometallic chemistry》2004,689(2):352-360
Cyclopalladated complexes with the Schiff base N-(benzoyl)-N′-(2,4-dimethoxybenzylidene)hydrazine (H2L, 1) have been described. The reaction of 1 with Li2[PdCl4] in methanol yields the complex [Pd(HL)Cl] (2). [Pd(HL)(CH3CN)Cl] (3) has been prepared by dissolving 2 in acetonitrile. In methanol-acetonitrile mixture, treatment of 2 with two mole equivalents of PPh3 produces [PdL(PPh3)] (4) and that with one mole equivalent of PPh3 produces [Pd(HL)(PPh3)Cl] (5). Crystallization of 2 from dmso-d6 results into isolation of [Pd(HL)((CD3)2SO)Cl] (6). In 2, the monoanionic ligand (HL−) is C,N,O-donor and the Cl-atom is trans to the azomethine N-atom. In 3, 5 and 6, HL− is C,N-donor and the Cl-atom is trans to the metallated C-atom. The remaining fourth coordination site is occupied by the N-atom of CH3CN, the P-atom of PPh3 and the S-atom of (CD3)2SO in 3, 5 and 6, respectively. Thus on dissolution in acetonitrile and dmso and in reaction with stoichiometric PPh3 the incoming ligand imposes a rearrangement of the coordinating atoms on the palladium centre. On the other hand, in presence of excess PPh3 deprotonation of the amide functionality in 2 occurs and the Cl-atom is replaced by the P-atom of PPh3 to form 4. Here the dianionic ligand (L2−) remains C,N,O-donor as in 2. The compounds have been characterized with the help of elemental analysis (C, H, N), infrared, 1H NMR and electronic absorption spectroscopy. Molecular structures of 3, 4, and 6 have been determined by X-ray crystallography. 相似文献
11.
Bhupendra P. Joshi 《Tetrahedron》2005,61(12):3075-3080
An ultrasound-assisted convenient method was developed for the conversion of toxic methoxylated cis-isomer of arylalkenes into its hypolipidemic active trans-isomer. Treatment of cis-isomer or mixture of all three isomers (1a-1j) with ammonium formate and 10% Pd/C gave arylalkanes (2a-2j), which upon oxidation with DDQ in anhydrous dioxane containing a little amount of silica gel, provided (E)-arylalkenes (3a-3g) in 42-72% yield depending upon the substituents attached at the aryl ring. The same method, upon addition of a few drops of water, provided hypolipidemic active arylalkanones (3h-3j) in 59-65% yield. 相似文献
12.
G. Brancatelli 《Journal of organometallic chemistry》2007,692(25):5598-5604
The [Pd(N-N∗)Cl2] complexes have been obtained, as yellow solids, in almost quantitative yields; N-N∗ indicate bidentate chiral ligands (Sa)-1, (Sa)-2, (S,S)-3, (R,R)-4, containing the rigid 2-pyridinyl or 8-quinolinyl building block skeleton and the C2-symmetric chiral framework trans-2,5-dimethylpyrrolidinyl or (S)-(+)-2,2′-(2-azapropane-1,3-diyl)-1,1′-binaphthalene. The ligands pairs have the same C2-symmetric chiral framework but different building block skeleton, beyond that for the basicity in the N-donor atoms, for rigidity and flexibility features. The N-N∗ ligands act as chelating ligands leading a square planar geometry. The compounds [Pd(S,S-3)Cl2] and [Pd(R,R-4)Cl2] have been also characterised by X-ray diffraction. The rigidity and flexibility features of (S,S)-3 and (R,R)-4 ligands induce a different orientation of the trans-2,5-dimethylpyrrolidinyl moiety with respect to the pyridinyl and quinolinyl plane. This work shows that intrinsic rigidity and flexibility are not enough to define the ligand properties and to preview the effects that they induce on the reactivity of the metal complex. 相似文献
13.
Susie Douglas Mary F. Mahon Michael K. Whittlesey 《Journal of organometallic chemistry》2005,690(23):5027-5035
Addition of excesses of N-heterocyclic carbenes (NHCs) IEt2Me2, IiPr2Me2 or ICy (IEt2Me2 = 1,3-diethyl-4,5-dimethylimidazol-2-ylidene; IiPr2Me2 = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene; ICy = 1,3-dicyclohexylimidazol-2-ylidene) to [HRh(PPh3)4] (1) affords an isomeric mixture of [HRh(NHC)(PPh3)2] (NHC = IEt2Me2 (cis-/trans-2), IiPr2Me2 (cis-/trans-3), ICy (cis-/trans-4) and [HRh(NHC)2(PPh3)] (IEt2Me2(cis-/trans-5), IiPr2Me2 (cis-/trans-6), ICy (cis-/trans-7)). Thermolysis of 1 with the aryl substituted NHC, 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene (IMesH2), affords the bridging hydrido phosphido dimer, [{(PPh3)2Rh}2(μ-H)(μ-PPh2)] (8), which is also the reaction product formed in the absence of carbene. When the rhodium precursor was changed from 1 to [HRh(CO)(PPh3)3] (9) and treated with either IMes (=1,3-dimesitylimidazol-2-ylidene) or ICy, the bis-NHC complexes trans-[HRh(CO)(IMes)2] (10) and trans-[HRh(CO)(ICy)2] (11) were formed. In contrast, the reaction of 9 with IiPr2Me2 gave [HRh(CO)(IiPr2Me2)2] (cis-/trans-12) and the unusual unsymmetrical dimer, [(PPh3)2Rh(μ-CO)2Rh(IiPr2Me2)2] (13). The complexes trans-3, 8, 10 and 13 have been structurally characterised. 相似文献
14.
The C,N-(trimethylsilyliminodiphenylphosphoranyl)silylmethylmetal complexes [Fe(L)2] (3), [Co(L)2] (4), [ZrCl3(L)]·0.83CH2Cl2 (5), [Fe(L)3] (6), [Fe(L′)2] (7) and [Co(L′)2] (8) have been prepared from the lithium compound Li[CH(SiMe2R)P(Ph)2NSiMe3] [1a, (R = Me) {≡ Li(L)}; 1b, (R = NEt2) {≡ Li(L′)}] and the appropriate metal chloride (or for 7, FeCl3). From Li[N(SiMe3)C(Ph)C(H)P(Ph)2NSiMe3] [≡ Li(L″)] (2), prepared in situ from Li(L) (1a) and PhCN, and CoCl2 there was obtained bis(3-trimethylsilylimino- diphenylphosphoranyl-2-phenyl-N-trimethylsilyl-1-azaallyl-N,N′)cobalt(II) (9). These crystalline complexes 3-9 were characterised by their mass spectra, microanalyses, high spin magnetic moments (not 5) and for 5 multinuclear NMR solution spectra. The X-ray structure of 3 showed it to be a pseudotetrahedral bis(chelate), the iron atom at the spiro junction. 相似文献
15.
A series of new para-substituted (E)-(N)-styrylcarbazoles, i.e., eight (E)-9-[2-(aryl)ethenyl]-9H-carbazoles (5-12) and 1,4-bis[(E)-2-(9H-carbazol-9-yl)vinyl]benzene (13), have been synthesized in high yield and stereoselectively by a sequential silylative coupling-Hiyama coupling reaction, i.e., coupling of commercially available 9-vinylcarbazole with vinyltriethoxysilane or divinyltetramethyldisiloxane in the presence of [RuHCl(CO)(PCy3)2] (I), followed by Pd (II) catalyzed cross-coupling with para-substituted iodobenzenes.The tandem procedure has facilitated the synthesis of 13. X-ray structures of the intermediate silylvinylcarbazole (4), as well as products 12 and 13 have been obtained. 相似文献
16.
Shin-ichi NayaMakoto Nitta 《Tetrahedron》2003,59(21):3709-3718
Novel condensation reaction of tropone with N-substituted and N,N′-disubstitued barbituric acids in Ac2O afforded 5-(cyclohepta-2′,4′,6′-trienylidene)pyrimidine-2(1H),4(3H),6(5H)-trione derivatives (8a-f) in moderate to good yields. The 13C NMR spectral study of 8a-f revealed that the contribution of zwitterionic resonance structures is less important as compared with that of 8,8-dicyanoheptafulvene. The rotational barriers (ΔG‡) around the exocyclic double bond of mono-substituted derivatives 8a-c were obtained to be 14.51-15.03 kcal mol−1 by the variable temperature 1H NMR measurements. The electrochemical properties of 8a-f were also studied by CV measurement. Upon treatment with DDQ, 8a-c underwent oxidative cyclization to give two products, 7 and 9-substituted cyclohepta[b]pyrimido[5,4-d]furan-8(7H),10(9H)-dionylium tetrafluoroborates (11a-c·BF4− and 12a-c·BF4−) in various ratios, while that of disubstituted derivatives 8d-f afforded 7,9-disubstituted cyclohepta[b]pyrimido[5,4-d]furan-8(7H),10(9H)-dionylium tetrafluoroborate (11d-f·BF4−) in good yields. Similarly, preparation of known 5-(1′-oxocycloheptatrien-2′-yl)-pyrimidine-2(1H),4(3H),6(5H)-trione derivatives (14a-d) and novel derivatives 14e,f was carried out. Treatment of 14a-c with aq. HBF4/Ac2O afforded two kinds of novel products 11a-c·BF4− and 12a,c·BF4− in various ratios, respectively, while that of 14d-f afforded 11d-f. The product ratios of 11a-c·BF4− and 12a-c·BF4− observed in two kinds of cyclization reactions were rationalized on the basis of MO calculations of model compounds 20a and 21a. The spectroscopic and electrochemical properties of 11a-f·BF4− and 12a-c·BF4− were studied, and structural characterization of 11c·BF4− based on the X-ray crystal analysis and MO calculation was also performed. 相似文献
17.
Azadeh Tadjarodi Forough Adhami Younes Hanifehpour Maryam Yazdi Zohreh Moghaddamfard Guido Kickelbick 《Polyhedron》2007
Three new compounds of aryl thiourea derivatives, namely N-2-(4-picolyl)-N′-(4-methoxyphenyl)thiourea (L1), N-2-(6-picolyl)-N′-(4-methoxyphenyl)thiourea (L2) and N-2-(4-picolyl)-N′-(4-nitrophenyl)thiourea (L3), and the new copper(II) complex [Cu(4PicTz4OMePh)(OAC)(EtOH)] (C1), as a result of oxidative cyclization of the ligand (L1), were synthesized. In addition, pure precursor (P1), as the product of the oxidative cyclization of N-(2-pyridyl)-N′-(4-methoxyphenyl)thiourea (L4), was isolated and characterized. Ligands (L1) and (L2) were characterized by 1H and 13C NMR and single crystal X-ray analysis. 1H NMR spectroscopy showed strong hydrogen bonding interactions between N′H-functionalities and the pyridine nitrogen atoms as well as weak intermolecular hydrogen bonding between the thione sulfur and the NH hydrogen. Structural studies of complex (C1) showed that the copper ion is five-coordinated with a square-pyramidal environment. The oxidative cyclization of ligand (L1) results in an anionic bidentate ligand in complex (C1). Both ligand (L1) and precursor (P1) crystallize as centrosymmetric dimers. 相似文献
18.
19.
Noemí Andrade-López Tracy A. Hanna José G. Alvarado-Rodríguez Adriana Luqueño-Reyes Bernat A. Martínez-Ortega Daniel Mendoza-Espinosa 《Polyhedron》2010
Cis-diaquobis{di-(2-pyridyl)-N-ethylimine}nickel(II) chloride (2) was obtained from the reaction of di-(2-pyridyl)-N-ethylimine (1) and [NiCl2dppe] [dppe = cis-1,2-bis(diphenylphosphino)ethylene] in a 2:1 ratio in hot acetonitrile. Cis-dichloro{di-(2-pyridyl)-N-ethylimine}palladium(II) (3) and cis-dichloro{di-(2-pyridyl)-N-ethylimine}platinum(II) (4) complexes were obtained from the reaction of MCl2 (M = Pd, Pt) and (1) in equimolar ratio in hot acetonitrile. Compounds 1–4 were characterized by IR spectroscopy, elemental analysis, and mass spectrometry; the complexes 3 and 4 were characterized in solution by NMR. In addition, solid state structures of compounds 1–4 were determined using single crystal X-ray diffraction analyses. X-ray diffraction data of the complexes 3 and 4 showed a distorted square planar local geometry at palladium and platinum atoms with the chlorine atoms in a cis-coordination; in 2 a local octahedral geometry at nickel atom was observed. Complexes 3 and 4 are arranged as dimers with a M?M distance of 3.4567(4) Å (M = Pd) and 3.4221(4) Å (M = Pt), respectively; 2 consists of units linked by intermolecular hydrogen bonding. 相似文献
20.
Joel Vargas 《European Polymer Journal》2004,40(7):1325-1335
Ring-opening metathesis polymerization (ROMP) of exo-N-(1-adamantyl)-7-oxanorbornene-5,6-dicarboximide (AdONDI) (3a), exo-N-cyclohexyl-7-oxanorbornene-5,6-dicarboximide (ChONDI) (3b) and exo-N-phenyl-7-oxanorbornene-5,6-dicarboximide (PhONDI) (3c) using well-defined alkylidene ruthenium catalysts (PCy3)2(CI)2RuCHPh (I) and (1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) (PCy3)CI2RuCHPh (II) was studied. The catalysts I and II gave polymers with around 70% and 50% trans vinylene content, respectively. The homopolymer of 3a had a Tg of 198 °C, while poly-3b showed a Tg of 122 °C. Copolymers of 3a, 3b and 3c with norbornene (NB) showed significant Tg increases over poly-NB. 相似文献