Showing papers on "Denticity published in 1983"
TL;DR: In this article, a chelates tris RuBL 2 x+ (x=1 ou 2) avec B=coordinat bidente and L=pap ou tap.
Abstract: Formation de chelates tris RuBL 2 x+ (x=1 ou 2) avec B=coordinat bidente et L=pap ou tap. Etude electrochimique dans l'acetonitrile
178 citations
TL;DR: In this article, an unusual trimeric CuII species of formula [Cu3(OH)(pz)3(Hpz),2(NO3)2]·H2O (HpZ = pyrazole) has been prepared from air oxidation of [Cu(Pz)2( NO3)] in the presence of moisture.
Abstract: An unusual trimeric CuII species of formula [Cu3(OH)(pz)3(Hpz)2(NO3)2]·H2O (Hpz = pyrazole) has been prepared from air oxidation of [Cu(Hpz)2(NO3)] in the presence of moisture. The X-ray structure of the oxidation product has been determined by single-crystal diffractometer techniques, and has been compared with a few related structures, all containing the pyramidal trimeric unit Cu3(OH). The compound crystallizes in the space group P21 with a= 7.756(2), b= 17.639(3), c= 8.883(1)A, β= 91.18(1)°, and Z= 2. The intensities of 3 640 independent reflections were used to determine the structure. The structure was solved and refined using standard heavy-atom and least-squares techniques to a residual R value of 0.0241 for 3 128 reflections with I > 2σ(I). The structure consists of trimeric units Cu3(OH)(pz)3 containing an almost flat Cu3N6 ring and a pyramidal Cu3O group with Cu–O distances of 1.994 A and an (averaged) Cu–O–Cu angle of 114°. Each copper is co-ordinated by four ligands in an almost square planar manner with two nitrogens from the bridging pyrazolato-groups and one oxygen from the bridging OH group. The fourth equatorial ligand is either the N-atom of a neutral pyrazole (for two Cu atoms) or the oxygen of a unidentate co-ordinating nitrato-ligand (for the third Cu atom). The fifth axial ligand for each copper ion is another nitrato-group. This nitrato-group links trimers together in chains, with two oxygens bound to coppers of one trimer, and the third oxygen binding to the third copper of the neighbouring trimer, resulting in chains of –O2NO–CuCu2O2NO–CuCu2–O2–. The dominant magnetic exchange in the structure occurs within each trimer, resulting in a compound having only one unpaired spin per three copper ions. An additional magnetic exchange interaction occurs between the trimers, using the nitrate-bridged chain. This interaction is only evident at very low temperatures. Due to the occurrence of rapid spin-lattice relaxation no e.s.r. spectra can be obtained at ambient temperatures, but instead n.m.r. spectra have been recorded.
92 citations
TL;DR: In this article, a discussion is given of the formation of complexes of the reaction of 1,4-di-t-butyl-1, 4-diaza-1-3-butadiene t-Bu-NCC-N-T-Bu (t-bu-DAB) or of t-NCH-2-C 5 H 4 N (tBu-Pyca) with Et 2 Zn or Et 3 Al.
83 citations
TL;DR: In this article, a macromonocyclic ligand 1,10-diaza-4,7,13,16-tetraoxacyclooctadecane-N,N'-diacetic acid (dacda) has been prepared and characterized.
Abstract: The principles of designing lanthanide (Ln) ion selective macrocyclic reagents are discussed. Factors such as the size of the metal ion, the cavity size of the ligand, the stereochemical constraint imposed on the ligand, and the overall coordination number of the multidentate ligand are considered. On the basis of these principles, the macromonocyclic ligand 1,10-diaza-4,7,13,16-tetraoxacyclooctadecane-N,N'-diacetic acid (dacda) has been prepared and characterized. stability constants of dacda complexes of various metal ions are reported. Except for a few metal ions such as copper (II), lead (II), and cadmium (II), dacda shows unique selectivity toward lanthanide ions as a group. Also, for the first time in aqueous solution for a multidentate ligand, the stability constants for Ln-ligand complexes decrease with increasing atomic number for heavy lanthanides and remain roughly unchanged for the lighter lanthanides. These data are discussed, and the structures of the complexes are proposed. 3 figures, 1 table.
81 citations
TL;DR: The preparation and properties of ruthenium (Ru) (II) complexes containing the bidentate ligand (L) 1-(2-pyridyl)-3,5-dimethylpyrazole, are described in this paper.
Abstract: The preparations and properties of ruthenium (Ru) (II) complexes containing the bidentate ligand (L) 1-(2-pyridyl)-3,5-dimethylpyrazole, are described. The tris complex RuL/sub 3//sup 2 +/ is shown to readily undergo photosubstitution in acetonitrile (CH/sub 3/CN) solution to produce RuL/sub 2/(CH/sub 3/CN)/sub 2//sup 2 +/, which in the presence of other bidentate ligands undergoes thermal substitution of the coordinated acetonitrite. /sup 1/H, /sup 13/C, and /sup 99/Ru NMR spectra are reported for all the complexes. Proton and carbon-13 NMR reveal the CH/sub 3/CN presence of geometrical isomerism, where it exists; proton and ruthenium-99 NMR allow the evaluation of the percentage of these isomers. Ruthenium-99 NMR proves to be an excellent probe of electron density at the metal and is possibly useful to evaluate the amount of ..pi..-back-bonding depending on the ligands. Electronic spectral data and oxidation potential measurements are given for comparison with those of the well-known RU(bipyridine)/sub 3//sup 2 +/ complex but do not lead to consistent results. 4 figures, 3 tables.
77 citations
TL;DR: In this paper, the authors describe the crystal structures of di-η5-cyclopentadienyl-1,2-dimethoxyethaneytterbium(II) with mono-clinic, space group Cc, with a 925(2), b 2349(5), c 823(2) A, β 12359(4)° and Z 4
58 citations
TL;DR: In this article, the preparation of monomeric areneruthenium(II) acetates and trifluoroacetates from the corresponding dihalides [Ru(η-arene)X(O2CR)2] is described.
Abstract: The preparation of monomeric areneruthenium(II) acetates and trifluoroacetates [Ru(η-arene)X(O2CR)] and [Ru(η-arene)(O2CR)2](X = Cl or Br; R = Me or CF3; arene = C6H6, p-MeC6H4CHMe2, C6H3Me3-1,3,5, C6H2Me4-1,2,4,5, or C6Me6)(not all possible combinations) from the corresponding dihalides [{Ru(η-arene)X2}2] is described. Infrared spectra suggest that the complexes [Ru(η-arene)X(O2CR)] contain a bidentate carboxylate group and that [Ru(η-arene)(O2CR)2] contain one bi- and one uni-dentate carboxylate group, which are apparently equivalent on the n.m.r. time-scale at room temperature. Reaction of trifluoroacetic acid with [{Ru(η-C6Me6)Cl2}2] gives a complex of empirical formula Ru(η-C6Me6)Cl(O2CCF3)·CF3CO2H which may be a salt [(η-C6Me6)Ru(η-Cl)2(µ-O2CCF3)Ru(η-C6Me6)][H(O2CCF3)2]·CF3CO2H. Triphenylphosphine converts [Ru(η-C6Me6)(O2CR)2](R = Me or CF3) into [Ru(η-C6Me6)(O2CR)2(PPh3)] in which both carboxylate groups are unidentate. The trifluoroacetate group is completely displaced from [Ru(η-C6H6)Cl(O2CCF3)] by pyridine (py) or ethyldiphenylphosphine to give [Ru(η-C6H6)ClL2]+(L = py or PEtPh2), isolated as PF6– or BPh4– salts. The potentially binucleating ligands pyrazine (pyz), 4,4′-bipyridyl, and 1,3-dithiane react either with [Ru(η-C6H6)Cl(O2CCF3)] or with [{M(η-p-MeC6H4CHMe2)Cl2}2](M = Ru or Os) in the presence of NH4PF6 or NaBPh4 in methanol to give [M(η-arene)ClL2]+ salts in which only one donor atom of the ligand is co-ordinated, but pyz and [{Ru(η-p-MeC6H4CHMe2)Cl2}2] react in dry tetrahydrofurane to give the pyrazine-bridged species {Ru(η-p-MeC6H4CHMe2)Cl2}2(µ-pyz). The structure of the complex [Ru(η-p-MeC6H4CHMe2)Cl(pyz)2]PF6 has been verified by X-ray analysis. The crystals are triclinic, space group P, with a= 9.265(2), b= 9.684(4), c= 12.969(2)A, α= 86.51(2), β= 72.89(2), and γ= 85.59(2)°.
54 citations
TL;DR: In this article, the formation of several complexes of cis -Pt(NH 3 ) 2 Pt(II) with the 1-methyluracil anion 1-MeU, C 5 H 5 N 2 O 2, is reported.
46 citations
TL;DR: In this article, a mixture of ligand and metal salt (4:1 molar ratio) in ethanol2triethyl orthoformate was used to synthesize hexacoordinated guanine complexes with 3 d metal perchlorates, which are monomeric with terminal unidentate LH, coordinating through the N(9) imidazole ring nitrogen.
44 citations
TL;DR: In this paper, the crystal structures of two bone growth regulators (diphosphonates and pyrophosphates) were determined from single crystal X-ray diffractometer data.
44 citations
TL;DR: In this paper, the magnetic and spectral properties of the Co(II) and Ni (II) complexes support octahedral stereochemistry, whilst tetragonally distorted octagonal geometry is suggested for the Cu(II)-complex.
TL;DR: The trivalent ruthenium, rhodium and iridium complexes of dipicolinic acid and its mixed ligand complexes with several nitrogen, oxygen donor molecules, of types: Na[M(dipic) 2 ]·2H 2 O and [M(Dipic)(N-O)]· n H 2 O as discussed by the authors, have been synthesized and characterised on the basis of elemental analyses, electrical conductance, magnetic susceptibility measurements and spectral (electronic and infrared) data.
TL;DR: The first transition metal complexes containing ortho-nitroaryl ligands were proposed in this paper. But they did not contain ortho -nitro-cyclic ligands.
TL;DR: In this article, the X-ray crystal structures of Mn2R4(PMe3)2, Mn2(CH2SiMe3), CH2CMe3, and CH2Ph have been determined.
Abstract: The reactions of manganese(II) dialkyls with tertiary phosphines or of MnCl2 with magnesium dialkyls in the presence of phosphines leads to dimeric complexes of stoicheiometry Mn2R4(PMe3)2(R = CH2SiMe3, CH2CMe3, and CH2Ph) and Mn2(CH2SiMe3)4(PR3)2[R3= Et3, Me2Ph, McPh2, and (cyclo-C6H11)3]. The X-ray crystal structures of Mn2(CH2CMe3)4(PMe3)2, Mn2(CH2Ph)4(PMe3)2, and Mn2(CH2SiMe3)4(PMePh2)2 have been determined. In the dimers there are two asymmetrically bridging alkyl groups with one additional terminal alkyl and one phosphine per manganese. The structures show a variation in bond lengths probably due to steric effects, with Mn–Mn distances of 2.667(1)–2.828(1)A, and long Mn–P distances [2.562(1)–2.684(1)A]. There is a close contact between one hydrogen atom on each of the bridging methylene groups and the manganese atom (Mn ⋯ H–C 2.15–2.29 A). Infrared and e.s.r. spectra of the compounds are discussed.
TL;DR: In this paper, the oxidation and reduction behavior in acetonitrile solution of copper(II) complexes with a complete series of quadri-and quinque-dentate amine macrocycles has been studied by electrochemical techniques.
Abstract: The oxidation and reduction behaviour in acetonitrile solution of copper(II) complexes with a complete series of quadri- and quinque-dentate amine macrocycles has been studied by electrochemical techniques. Both anodic and cathodic electrode processes are found to involve complicated mechanisms. However, the redox changes CuIII→CuII and CuII→CuI have been demonstrated through cyclic voltammetry at high potential scan rate. The E½ values for the above processes are discussed in terms of the properties and structural features of the macrocyclic ligands.
TL;DR: In this article, the X-ray crystal structure of [PtII(L)2]Br2·2H2O was determined, and the geometry of the complex cation is essentially square planar with one uncoordinated nitrogen atom per bound amine ligand.
Abstract: 1,4,7-Triazacyclononane (L) reacts with [PtCl4]2– in aqueous solution to form a variety of complexes containing the potentially tridentate amine as a uni- or bi-dentate ligand. The complex [PtII(L)2]Br2·2H2O containing two bidentate ligands was oxidised by molecular oxygen in aqueous solution to form the octahedral cation [PtIV(L)2]4+. 1H N.m.r. spectra indicated that the two cyclic amines were co-ordinated via six N-donor atoms. The X-ray crystal structure of [PtII(L)2]Br2·2H2O was determined. The complex crystallises in space group P2/n, with a= 8.990(2), b= 7.987(2), c= 14.424(4)A, β= 93.34(2)°, and Z= 2. 1 419 Independent reflections with I > 2.5σ(I) gave R= 0.0335. The geometry of the complex cation is essentially square planar with one unco-ordinated nitrogen atom per bound amine ligand.
TL;DR: In this paper, the preparation of t-BuDiNC complexes with bis(t-butyl-4 isocyano-2 phenoxy) ethane is described.
Abstract: Preparation des complexes [M(t-BuDiNC) 3 ](PF 6 ) z (M=Cr, z=0,1,2; M=Mn, z=1,2; M=Fe, z=2, M=Co, z=3) avec t-BuDiNC: bis(t-butyl-4 isocyano-2 phenoxy) ethane. Spectres IR, UV-visible et RMN de 13 C
TL;DR: In this article, the first reports of nitrophenylgold(I) complexes were reported. But the results were based on a mixture of neutral monodentate ligands and neutral mononuclear complexes.
TL;DR: In this article, the crystal and molecular structure of Cl3SnCH2CH2 CH2CH 2CH2CO2Et is reported, where the tin atom is 5 coordinate with two chlorines and carbon equatorial and the remaining chlorine and the carbonyl oxygen axial, in a distorted trigonal bipyramidal arrangement.
TL;DR: In this paper, the crystal structural analysis of 1a showed it to have a distorted tetrahedral configuration, in which a PF6 ligand behaved as a bidentate ligand.
TL;DR: In this article, the crystal structures of the L2Cu(3-py(CO2)) and L2cu(2, 3-py (CO2)(COOH)) (L = triphenylphosphine) complexes have been determined and characterized by infrared spectra.
Patent•
02 Feb 1983
TL;DR: In this paper, the nickel (II) complex is a square planar species with a trivalent Group V donor ligand, preferably a phosphine or phosphite ligand and a bidentate dithio ligand.
Abstract: Catalyst systems for the oligomerization and/or isomerization of olefins which comprise a nickel (II) complex and a co-catalyst. The nickel (II) complex is a square planar species with a trivalent Group V donor ligand, preferably a phosphine or phosphite ligand, a halogen or pseudo-halogen ligand and a bidentate dithio ligand, especially a substituted dithio- beta -diketone ligand.
TL;DR: In this article, the Schiff bases from 2-pyridine-carbaldehyde, 2-acetyl pyridine with (−)-1-phenylethylamine and (−)-3-aminomethylpinane were synthesized and a conformational analysis established which of the diastereomers is the thermodynamically more stable one.
TL;DR: In this article, the spectral properties of the complexes with these two ligands can be rationalized by assuming that the amino group of the pendant arm is axially coordinated to the metal ion giving a pentacoordinate structure, whereas the dimethylamino group of 2 cannot bind because of sterical hindrance.
Abstract: The two macrocycles 1-(2-aminoethyl)- and 1-[2-(dimethylamino)ethyl]-4, 8, 11-trimethyl-1, 4, 8, 11-tetraazacyclotetradecane, 1 and 2, respectively, and their metal complexes with Co2+, Ni2+ and Cu2+ were prepared. The different spectral properties of the complexes with these two ligands can be rationalized by assuming that, in the case of 1, the amino group of the pendant arm is axially coordinated to the metal ion giving a pentacoordinate structure, whereas the dimethylamino group of 2 cannot bind because of sterical hindrance. This is also corroborated by the observation that the complexes of 2 react with unidentate ligands such as N and SCN− to give ternary species MLX+, whereas those of 1 do not. This indicates that the complexes of 1 have no free coordination site, their coordination sphere being completely saturated by the five N-atoms of the macrocycle, whereas the complexes of 2 having a vacant site still can add an unidentate ligand.
TL;DR: In this paper, a tris-bidentate multidentate ligand, N,N′,N″-tris[2-(N-hydroxycarbamoyl)ethyl]-1,3,5-benzenetricarboxamide (BAMTPH), is described.
Abstract: Synthesis of a new tris-bidentate multidentate ligand, N,N′,N″-tris[2-(N-hydroxycarbamoyl)ethyl]-1,3,5-benzenetricarboxamide (BAMTPH), designed for the binding of trivalent metal ions such as Fe(III), Ga(III), and Al(III), is described. Its cation binding affinities for hydrogen ion and for Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Ga(III), and Al(III) ions are described, and the equilibrium data are compared with those of analogous ligands. The binding constants of trivalent metal ions with the ligand do not show a chelate effect relative to the binding to individual bidentate hydroxamic acids.
TL;DR: In this article, the crystal structures of the UO 2 (S 2 PMe 2 ) 2 · Me 3 PO was determined for two alcohol adducts, two chlorocomplexes and the phosphine oxide adduct.
TL;DR: In this article, it was shown that the dione acts as a bidentate ligand about trigonal bipyramidal tin which carries apical and equatorial chloro ligands which are magnetically non-equivalent at low temperature, but undergo positional exchange as the temperature is raised.
Patent•
30 Aug 1983
TL;DR: In this paper, a 3,3,4,4'-biphenyltetracarboxylic acid tetraester (s-BPTT) was produced by the stepwise oxidation coupling reaction of an o-phthalic acid ester at a high temperature in a molecular oxygen atmosphere, by adding a specific palladium catalyst successively to the reaction system.
Abstract: PURPOSE: To produce 3,3',4,4'-biphenyltetracarboxylic acid tetraester (s-BPTT), selectively, in hight yield, by the stepwise oxidation coupling reaction of an o- phthalic acid ester at a high temperature in a molecular oxygen atmosphere, by adding a specific palladium catalyst successively to the reaction system. CONSTITUTION: The objective s-BPTT is produced by the oxidative coupling reaction of o-phthalic acid ester at 140W260°C in the presence of a catalyst composed of a Pd salt (preferably Pd acetate and nitrate), a basic bidentate compound (preferably 1,10-phenanthroline) and a copper salt while supplying the reaction system with a gas containing molecular oxygen. The amounts of the bidentate compound and the copper salt are 0.5W4mol and 0.01W5mol per 1mol of the Pd salt, respectively, and the amount of the catalyst is 0.00005W0.005mol, preferably 0.0001W0.004mol in terms of Pd salt based on 1mol of the o-phthalic acid ester. The catalyst is added to the system 1W10 times within the range to give the total amount of the Pd salt of 0.0001W0.01mol per 1mol of the ester, and the ester is made to react stepwise under the above condition to obtain s-BPTT. COPYRIGHT: (C)1985,JPO&Japio
TL;DR: EPR spectra showed that the ternary adduct is a mixture of two species, both characterized by the presence in the EPR spectrum of a superhyperfine structure from two protein nitrogens and by a low g parallel value, indicative of coordination to sulfur ligands, suggested that the two species contain the metal as penta- and hexacoordinated, respectively.
TL;DR: In this paper, the synthesis, characterization, and phosphorus-3 1 NMR spectra of 17 new diphenylphosphido-bridged dirhodium complexes of bidentate and monodentate phosphines are presented.
Abstract: The syntheses, characterization, and phosphorus-3 1 NMR spectra of 17 new diphenylphosphido-bridged dirhodium complexes of bidentate and monodentate phosphines are presented. Treatment of [RhCI(COD)], and [IrCl(COD)], with lithium diphenylphosphide in THF at room temperature produces the corresponding diphenylphosphido-bridged complexes [ M(p-PPh2)(COD)], in excellent yields. The 1,5-cyclooctadiene (COD) ligands of [Rh(p(-PPh,)(COD)], are replaced stepwise by chelating diphosphines, LL (e.g., Ph2P(CH2),,PPhz, n = 1-4) to produce complexes of the types [(LL)Rh(p-PPh2)2Rh(COD)] and [Rh(p-PPh,)(LL)],. In contrast, reactions with the monodentate phosphines PPh,, PMePh,, PEt,, and PCy, yield only "mixed" phosphine-COD complexes of the types (R3P)2Rh(pPPh2)2Rh(COD) and (Cy,P)Rh(p-PPh,),Rh(COD). These unusual complexes possess a rhodium-rhodium bond, two dissymmetrically bridging diphenylphosphido groups, and two different stereochemistries around the rhodium atoms. One rhodium is tetrahedral and surrounded by four phosphorus atoms, and the other rhodium (bonded to COD) is nearly planar. In the (R3P)2Rh(p-PPh2)2Rh(COD) complexes, the phosphorus resonance of the p-PPh, group is shifted downfield approximately 300 ppm compared to the position for analogous complexes of the chelating diphosphines; the large shift is attributed to the formation of the rhodium-rhodium bond.