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1.
The dinuclear palladium(I) complexes [L(Ar2HGe)Pd(μ‐GeAr2)2Pd(GeHAr2)L] (Ar=Ph, p‐Tol; L=PMe3, tBuNC) contain terminal germyl and bridging germylene ligands with the experimentally observed Ge???Ge bond lengths of 2.8263(4) Å (L=PMe3) and 2.928(1) Å (L=tBuNC), which are close to the longest Ge? Ge bond reported to date [2.714(1) Å]. Significant Ge???Ge interactions between the germylene and germyl ligands (PMe3 complexes > tBuNC complexes) are supported by DFT calculations, Wiberg bond indices (WBI), and natural bond orbital (NBO) analyses. Exchanging tBuNC for PMe3 ligands increases the Ge???Ge interaction, and simultaneously activates two Pd? Ge bonds. Adding the chelating diphosphine 1,2‐bis(diethylphosphino)ethane (depe) to the PMe3 complexes results in the intramolecular coupling of germyl and germylene ligands followed by extrusion of a digermane.  相似文献   

2.
Palladium(II) and platinum(II) complexes containing mixed ligands N-(2-pyridyl)acetamide (AH) or N-(2-pyrimidyl)acetamide (BH) and the diphosphines Ph2P(CH2) n PPh2, (n = 1, 2 or 3) have been prepared. The prepared complexes [Pd(A)2(diphos)] or [Pd(B)2(diphos)] have been used effectively to prepare bimetallic complexes of the type [(diphos)Pd(μ-L)2M′Cl2] where M′ = Co, Cu, Mn, Ni, Pd, Pt or SnCl2; L = A or B. The prepared complexes were characterized by elemental analysis magnetic susceptibility, i.r. and UV–Vis spectral data. 31P–{1H}-n.m.r. data have been applied to characterize the produced linkage isomers.  相似文献   

3.
Reaction of PPh2H with Pd(PPh3)4 in a 4:1 molar ratio produced the Pd complex with two diphenylphosphine ligands, Pd(PPh2H)2(PPh3)2 (1). Complex (1) was characterized by n.m.r. (1H and 31P{1H}) spectra as well as by elemental analysis. Reaction of (1) with RhCl(PPh3)3 yielded a Pd–Rh heterobimetallic complex with bridging phosphide ligands, formulated as [(Ph3P)2Pd(μ-PPh2)2Rh(PPh3)2]Cl (2).  相似文献   

4.
Two carboxamide ligands, H2bqbenzo {3,4-bis(2-quinolinecarboxamido)benzophenone} and H2bqb {N,N′-bis[(2-quinolinecarboxamide)-1,2-benzene]}, have been prepared using tetrabutylammonium bromide as an environmentally benign reaction medium. Two new Pd(II) complexes, [PdII(bqbenzo)] (1) and [PdII(bqb)] (2), have been synthesized, characterized, and their structures determined by single crystal X-ray diffraction. The di-anionic ligands, bqbenzo2? and bqb2?, are coordinated via two Namide atoms and the nitrogens of the two quinoline rings, with Pd?Namide < Pd–Nquinoline bond lengths. The geometry around palladium(II) in both complexes is distorted square planar. The electrochemical behaviors of the ligands and their Pd(II) complexes have been investigated by cyclic voltammetry in DMF. An irreversible PdII/I reduction is observed at ?1.06 V for 1 and at ?1.177 V for 2, indicating the influence of the R substituent on the central phenyl ring of carboxamide ligands on the PdII/I reduction potential. The ligands and palladium complexes were also screened for in vitro antibacterial activity. The Pd(II) complexes show strong biological activity against S.typhi and E.coli as Gram ?ve and B.cereus and S.aureus as Gram +ve bacteria comparable to the antibiotic penicillin. The antibacterial results also reveal that coordination of Pd(II) significantly improves the activity.  相似文献   

5.
Summary As an approach to systems containing methionine residues, 3-acetyl-4-hydroxy-6-methyl-2H-pyran-2-one (HDh, dehydroacetic acid) was treated with L-methionine (MetH) or L-methionine methylester (MetM). By condensation at the acyl group and transfer of the phenolic hydrogen on the nitrogen atom, the related ligands DhMetH and DhMetM, were isolated, and form complexes of formula [MX2(L)2](M = Pd or Pt, L = DhMetM, X = Cl, Br or I; L = DhMetH, X = Cl or Br) and [MI2(DhMetH)] with palladium and platinum dihalides. The reaction of the DhMetK carboxylate with MCl2 in various media is discussed. Ligands and complexes were characterized by i.r. and n.m.r. (1H and13C) spectroscopy and, in some cases, by thermogravimetric measurements. The ligands behave as monodentate sulphur donors, the 12 complexes showing atrans geometry except for [PtCl2(DhMetH)2], which is probably a mixture ofcis andtrans isomers.  相似文献   

6.
Bridged N,N′-substituted bisbenzimidazolium bromide salts (L1, L2, and L3) were synthesized and fully characterized. Reactions of palladium acetate with L1, L2, and L3 afforded corresponding new bridged bis(N-heterocyclic carbene)palladium(II) complexes (C1, C2, and C3) in high yields. The X-ray structure of complex C1 showed that the Pd(II) ion is bonded to the two carbon atoms of the bis(N-heterocyclic carbene) and two bromido ligands are in the cis position, resulting in a distorted square planar geometry. The three Pd(NHC)2Br2 complexes C1, C2, and C3 were evaluated in carbonylative Suzuki–Miyaura coupling reactions of aryl boronic acids with aryl halides and displayed high catalytic activity with low catalyst loading. The coupling reactions of aryl bromides were selective towards the carbonylation product at higher carbon monoxide pressure.  相似文献   

7.
A series of Zn (II), Pd (II) and Cd (II) complexes, [(L) n MX 2 ] m (L = L‐a–L‐c; M = Zn, Pd; X = Cl; M = Cd; X = Br; n, m = 1 or 2), containing 4‐methoxy‐N‐(pyridin‐2‐ylmethylene) aniline ( L‐a ), 4‐methoxy‐N‐(pyridin‐2‐ylmethyl) aniline ( L‐b ) and 4‐methoxy‐N‐methyl‐N‐(pyridin‐2‐ylmethyl) aniline ( L‐c ) have been synthesized and characterized. The X‐ray crystal structures of Pd (II) complexes [L 1 PdCl 2 ] (L = L‐b and L‐c) revealed distorted square planar geometries obtained via coordinative interaction of the nitrogen atoms of pyridine and amine moieties and two chloro ligands. The geometry around Zn (II) center in [(L‐a)ZnCl 2 ] and [(L‐c)ZnCl 2 ] can be best described as distorted tetrahedral, whereas [(L‐b) 2 ZnCl 2 ] and [(L‐b) 2 CdBr 2 ] achieved 6‐coordinated octahedral geometries around Zn and Cd centers through 2‐equivalent ligands, respectively. In addition, a dimeric [(L‐c)Cd(μ ‐ Br)Br] 2 complex exhibited typical 5‐coordinated trigonal bipyramidal geometry around Cd center. The polymerization of methyl methacrylate in the presence of modified methylaluminoxane was evaluated by all the synthesized complexes at 60°C. Among these complexes, [(L‐b)PdCl 2 ] showed the highest catalytic activity [3.80 × 104 g poly (methyl methacrylate) (PMMA)/mol Pd hr?1], yielding high molecular weight (9.12 × 105 g mol?1) PMMA. Syndio‐enriched PMMA (characterized using 1H‐NMR spectroscopy) of about 0.68 was obtained with Tg in the range 120–128°C. Unlike imine and amine moieties, the introduction of N‐methyl moiety has an adverse effect on the catalytic activity, but the syndiotacticity remained unaffected.  相似文献   

8.
Summary Reaction of 1 equivalent ofo-alkylaniline with Pd(OAc)2 gave the acetate bridged complexes [Pd(OAc)2L]2. The*H n.m.r. spectra showed downfield shifts for theo-benzylic protons indicating an above-plane geometry involving a significant interaction with the metal orbitals. Similar interactions were found for Pd(OAc)2L2 and Pd(OAc)2L(L) (L= differento-alkylaniline; t-butylpyridineetc.) prepared from the dimer and for Rh(CO)2Cl(L) complexes. Theo-benzylic carbons of the palladium complexes did not show downfield shifts in the13C n.m.r. spectra.  相似文献   

9.
The syntheses of 2‐(di‐tert‐butylphosphino)‐N,N‐dimethylaniline ( L1 , 71 %) and 2‐(di‐1‐adamantylphosphino)‐N,N‐dimethylaniline ( L2 , 74 %), and their application in Buchwald–Hartwig amination, are reported. In combination with [Pd(allyl)Cl]2 or [Pd(cinnamyl)Cl]2, these structurally simple and air‐stable P,N ligands enable the cross‐coupling of aryl and heteroaryl chlorides, including those bearing as substituents enolizable ketones, ethers, esters, carboxylic acids, phenols, alcohols, olefins, amides, and halogens, to a diverse range of amine and related substrates that includes primary alkyl‐ and arylamines, cyclic and acyclic secondary amines, N? H imines, hydrazones, lithium amide, and ammonia. In many cases, the reactions can be performed at low catalyst loadings (0.5–0.02 mol % Pd) with excellent functional group tolerance and chemoselectivity. Examples of cross‐coupling reactions involving 1,4‐bromochlorobenzene and iodobenzene are also reported. Under similar conditions, inferior catalytic performance was achieved when using Pd(OAc)2, PdCl2, [PdCl2(cod)] (cod=1,5‐cyclooctadiene), [PdCl2(MeCN)2], or [Pd2(dba)3] (dba=dibenzylideneacetone) in combination with L1 or L2 , or by use of [Pd(allyl)Cl]2 or [Pd(cinnamyl)Cl]2 with variants of L1 and L2 bearing less basic or less sterically demanding substituents on phosphorus or lacking an ortho‐dimethylamino fragment. Given current limitations associated with established ligand classes with regard to maintaining high activity across the diverse possible range of C? N coupling applications, L1 and L2 represent unusually versatile ligand systems for the cross‐coupling of aryl chlorides and amines.  相似文献   

10.
The Pd atom in each of the two title compounds, [Pd(NO3)2(C2H6OS)2], (I), and [Pd(NO3)2(C4H8OS)2], (II), coordinates two O atoms from two nitrate ligands and two S atoms from di­methyl sulfoxide (dmso) and thio­xane (systematic name: 1,4-oxathiane) ligands in a pseudo-square-planar cis-geometry. In the dmso complex, the distances to palladium are Pd—O 2.067 (2) and 2.072 (2) Å, and Pd—S 2.2307 (11) and 2.2530 (8) Å. The corresponding distances in the thio­xane complex are Pd—O 2.053 (3) and 2.076 (2) Å, and Pd—S 2.2595 (9) and 2.2627 (11) Å. Both compounds may be regarded as dimers with an inversion centre, where one of the coordinating nitrate O atoms in one mol­ecule also interacts with the Pd atom in the adjacent mol­ecule, with Pd—O distances of 2.849 (9) and 3.31 (3) Å in (I) and (II), respectively.  相似文献   

11.
The [Pd(cod)(cotl)]ClO4 complex (cod = cycloocta-1,5-diene; cotl = cyclooctenyl, C18H13 ) undergoes substitutions with new Schiff base ligands containing benzimidazole L [L = 2-(2-N-n-propylidenephenyl)benzimidazole (L1); 2-(2-N-i-propylidenephenyl)benzimidazole (L2); 2-(2-N-n-butylidenephenyl)benzimidazole (L3); 2-(2-N-i-butylidenephenyl)benzimidazole (L4)]. Facile displacement of cod by L occurs to produce complexes of the type [Pd(cotl)L]ClO4· nMe2CO (n= 0; L = L1, L2 or L3; n= 2, L = L4). Dihalobridge complexes of the type [Pd(cotl)X]2(X = Cl or Br) undergo halogen-bridge cleavage with L1–L4 to give mononuclear complexes of the type Pd(cotl)LX · nH2O (n= 2, X = Cl, L = L1; n= 0, X = Br, L = L1; n= 0, X = Cl, L = L2; n= 0, X = Cl or Br, L = L3; n= 0, X = Cl, L = L4; n= 2, X = Br, L = L4) and a binuclear complex [Pd(cotl)Br]2L2. The complexes were characterised by physical properties, i.r., 1H- and 13C-n.m.r. spectral techniques and by mass spectra. Probable structures have been proposed.  相似文献   

12.
Two diphosphane ligands – 2,5‐bis(2‐(diphenylphosphino)‐5‐R)phenyl)‐1,3,4‐oxadiazole ( L1 , R = H, L2 , R = OMe) and their binuclear complexes, L1Cu and L2Cu , were prepared and characterized. The molecular structures of L1Cu and L2Cu , as perchlorate salts, were established by X‐ray crystallography, which showed them to be binuclear complexes with each Cu atom tetrahedrally coordinated by two P atoms and two N atoms. The ligands and their Cu(I) complexes catalyzed Sonogashira coupling reactions of iodobenzene with phenylacetylene in the presence of K2CO3 under Pd‐free conditions. Coupling reactions catalyzed by L1 or L2 with Cu(MeCN)4ClO4 in situ exhibited better yields than those by the corresponding Cu(I) complexes L1Cu or L2Cu . Detailed studies showed L1 or L2 with Cu(MeCN)4ClO4 to be suitable catalysts for the coupling reaction of terminal alkynes and aryl halides. The coupling reactions of aryl iodides with electron‐withdrawing groups showed better results. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

13.
N-Carboethoxy-4-chlorobenzene thioamide (Hcct or HL) and N-carboethoxy-4-bromobenzene thioamide (Hcbt or HL) react with bivalent (Ni, Co, Cu, Ru, Pd and Pt), trivalent (Ru and Rh) and tetravalent (Pt) transition metal ions to give [MII(L)2], [RuIII(L)3], [RhIII(L)(HL)Cl2] and [Pt(L)2Cl2] complexes, respectively. In the presence of pyridine, CoII and NiII salts react with the ligands (HL) to give [MII(L)2Py] (M = Co and Ni) complexes. Soft metal ions abstract sulphur from the ligands to yield the corresponding sulphide, together with oxygenated forms of the ligands. All the metal complexes have been characterised by chemical analyses, conductivity, spectroscopic and magnetic measurements.  相似文献   

14.
Six new coordination polymers constructed from two structurally related ligands, 2,2′-bis(2-methylbenzimidazole) ether (L1) and 2,2′-bis(2-ethylbenzimidazole)ether (L2), have been synthesized. They are [Cu(L1)(bz)2] (1), [Cu(L2)(bz)2] (2), [Zn2(L1)(m-bdc)2] (3), [Cd2(L2)(m-bdc)2(H2O)]2·H2O (4), [Zn(L1)(OH-bdc)-(H2O)] (5) and [Zn2(L2)(btca)] (6), where Hbz = benzoic acid, m-H2bdc = 1,3-benzenedicarboxylic acid, OH-H2bdc = 5-hydroxyisophthalic acid, and H4btca = 1,2,4,5-benzenetetracarboxylic acid. In 1 and 2, the bidentate N-donor ligands (L1 and L2) bridge neighboring metal centers to form 1D single chains. The bz anions are attached on both sides of the chains. In 3 and 4, the N-donor ligands (L1 and L2) in cis conformations bridge two metal centers to generate a [M2(L1)]4+ unit (M = Zn(II) and Cd(II)). The adjacent [M2(L1)]4+ units are further linked via the dicarboxylate anions to form 1D double chain structures. In 5, the Zn(II) cations are bridged by OH-m-bdc anions to form an infinite polymeric chain. The L1 ligands are attached on one side of the chain in a monodentate mode. In 6, two Zn(II) cations are bridged by two L2 ligands to form a [ZnL2]2 4+ ring, which is further linked by btca anions to generate a 2D layer. The luminescent properties of the ligands and 3–6 in the solid state at room temperature were also studied.  相似文献   

15.
Transition metal complexes containing two types of ligands: 5-phenyl-1,3,4-oxadiazole-2-thione ion (L) and tertiary phosphines, have been prepared. The complexes, [ML2A2] [M = Pd or Pt; A = PPh3 or Ph2PCH2CH2P(O)Ph2] and [ML2B] (M = Co, Ni, Pd or Pt; B = Ph2PCH2PPh2 or Ph2PCH2CH2PPh2), were characterized by elemental analysis, molar conductance, i.r., u.v.–vis., 31P-n.m.r., magnetic susceptibility measurements and mass spectra.  相似文献   

16.
The systems MII-ONC(CN)2 -L-MeOH-H2O [M = Ni, Cu, Co or Pd; L = pyrazole (pz)] were studied to determine conditions for the nucleophilic addition of MeOH to nitrosodicyanomethanide (ndcm) in the metal coordination sphere. Compounds containing two or three bidentate anionic chelate ligands derived from methyl-2-cyano-2-(hydroxyimino)ethanimidic acid, H(mcoe), formed by nucleophilic addition of MeOH to ONC(CN)2 , were isolated: [Cu(mcoe)2(H2O)2] (elongated pseudo-octahedron with two water molecules at long axial distances), [Co(mcoe)3] (approximate octahedron) and [Pd(mcoe)2] (square-planar). In the CoII system, oxidation to CoIII took place. In addition, simple nitrosodicyanomethanide compounds [Ni(ndcm)2(pz)4] (nearly octahedral) and [Pd(ndcm)2(pz)2] (square-planar) were obtained. The crystal structure of trans-[Ni(ndcm)2(pz)4] has been elucidated by X-ray crystallography. The NiII atom is nearly octahedrally coordinated by four nitrogens of pz and two oxygens of (ndcm). This compound is the first example of a transition metal oxygen-coordinated nitrosodicyanomethanide complex with a short metal-oxygen bond. The remaining compounds were characterized by i.r. and electronic spectra. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

17.
Summary The compounds EtO2CCH2(Me)NCS2R (R = Me, ESDTM; R = Et, ESDTE) were prepared from sarcosine ethyl ester hydrochloride, CS2 and alkyl iodide in EtOH-H2O. These ligands react with palladium halides in benzene to yield the benzene solvates [Pd(ESDTR)X2nC6H6 (R = Me or Et; X = Cl or Br; n < 1), in which the dithioester molecule coordinates through both sulphur atoms. Ligands and complexes have been characterized by i.r. and 1H n.m.r. spectroscopy and by thermal analysis (t.g., d.t.g. and d.t.a.). The low stability of the adducts in both solution and solid phase is discussed on the basis of proton n.m.r. spectra. Thermal degradation of the 1∶1 complexes has been examined up to 1000° C. The first decomposition step involves release of alkyl halide to form the [Pd(ESDT)X] n (X = Cl or Br) intermediates, which successively decompose, finally giving palladium.  相似文献   

18.
Reaction of Na2[PdCl4] with the sodium salt of 5,5-diethylbarbituric acid (barbH) led to the formation of two complexes, [PdNa2(μ-barb)4(DMSO)2]·2H2O·DMSO (1), and {[PdNa2(μ-barb)4(H2O)]·3H2O}n (2). The complexes were characterized by elemental analysis, FT-IR, NMR, and X-ray crystallography. Complex 1 was crystallized from H2O/DMSO (1?:?1, v?:?v) and 2 was crystallized in H2O. Both complexes contain square planar [Pd(barb)4]2? moieties, in which Pd(II) is coordinated by four barb ligands via the negatively charged nitrogens. In addition to the coordination of a DMSO ligand, two Na(I) ions in 1 are bridged by carbonyl O of four barb ligands in the [Pd(barb)4]2? unit, while the Pd(II) and Na(I) ions in 2 are bridged by the barb ligands in a tetradentate bridging fashion leading to a 2-D polymeric network. The bridging of metal centers in both complexes result in a significantly short Na?Pd distance of ca. 2.95 Å. Contrary to 2, the coordination of DMSO to Na(I) in 1 avoids the extension of the polymeric structure.  相似文献   

19.
The crystal structure of the title compound, trans‐[Pd(NCS)2(C6H13N3P)2](NCS)2, is one of the few pal­ladium(II) complexes containing two protonated water‐soluble 1,3,5‐tri­aza‐7‐phos­pha­adamantane (PTA) ligands re­ported to date. The compound displays a distorted square‐planar geometry, with the Pd atom on an inversion centre and with the S atoms of the thio­cyanate counter‐ions occupying the axial positions above and below the equatorial plane described by the phosphine and thio­cyanate ligands. Geometric parameters for the formal coordination polyhedron include a Pd—P distance of 2.2940 (8) Å, a Pd—S distance of 2.3509 (8) Å and a P—Pd—S angle of 89.45 (3)°. The effective cone angle for the PTA ligands was calculated as 114.5°.  相似文献   

20.
The reaction of dichlorido(cod)palladium(II) (cod = 1,5‐cyclooctadiene) with 2‐(benzylsulfanyl)aniline followed by heating in N,N‐dimethylformamide (DMF) produces the linear trinuclear Pd3 complex bis(μ2‐1,3‐benzothiazole‐2‐thiolato)bis[μ2‐2‐(benzylsulfanyl)anilinido]dichloridotripalladium(II) N,N‐dimethylformamide disolvate, [Pd3(C7H4NS2)2(C13H12NS)2Cl2]·2C3H7NO. The molecule has symmetry and a Pd...Pd separation of 3.2012 (4) Å. The outer PdII atoms have a square‐planar geometry formed by an N,S‐chelating 2‐(benzylsulfanyl)anilinide ligand, a chloride ligand and the thiolate S atom of a bridging 1,3‐benzothiazole‐2‐thiolate ligand, while the central PdII core shows an all N‐coordinated square‐planar geometry. The geometry is perfectly planar within the PdN4 core and the N—Pd—N bond angles differ significantly [84.72 (15)° for the N atoms of ligands coordinated to the same outer Pd atom and 95.28 (15)° for the N atoms of ligands coordinated to different outer Pd atoms]. This trinuclear Pd3 complex is the first example of one in which 1,3‐benzothiazole‐2‐thiolate ligands are only N‐coordinated to one Pd centre. The 1,3‐benzothiazole‐2‐thiolate ligands were formed in situ from 2‐(benzylsulfanyl)aniline.  相似文献   

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