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Chelate Complexes (chelate + complex)
Selected AbstractsMesomerization of S4 -Symmetric Tetrahedral Chelate Complex [In4(L3)4]: First-Time Monitored by Temperature-Dependent 1H NMR Spectroscopy,,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2010Rolf W. Saalfrank Abstract VT 1H NMR spectroscopy proved that a non-dissociative and reversible mesomerization process links the tetranuclear indium(III) complexes meso -(,,,,,,,)(P,P,M,M)- 3 and meso -(,,,,,,,)(M,M,P,P)- 3,. During this process four tandem Bailar twists, resulting in the (,)/(,) isomerization at the indium centers, and the (P)/(M) inversion of the four coordinating face-centered, helical ligands (L3)3, are involved. In addition, gas-phase DFT calculations (B3LYP/LANL2DZp) revealed a C1 -symmetric transition state (+21.9 kcal,mol,1) for the mesomerization mechanism which connects 3 and 3,. [source] Minocycline-Based Europium(III) Chelate Complexes: Synthesis, Luminescent Properties, and Labeling to StreptavidinHELVETICA CHIMICA ACTA, Issue 11 2009Takuya Nishioka Abstract Two chelate ligands for europium(III) having minocycline (=(4S,4aS,5aR,12aS)-4,7-bis(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxonaphthacene-2-carboxamide; 5) as a VIS-light-absorbing group were synthesized as possible VIS-light-excitable stable Eu3+ complexes for protein labeling. The 9-amino derivative 7 of minocycline was treated with H6TTHA (=triethylenetetraminehexaacetic acid=3,6,9,12-tetrakis(carboxymethyl)-3,6,9,12-tetraazatetradecanedioic acid) or H5DTPA (=diethylenetriaminepentaacetic acid=N,N -bis{2-[bis(carboxymethyl)amino]ethyl}glycine) to link the polycarboxylic acids to minocycline. One of the Eu3+ chelates, [Eu3+(minocycline-TTHA)] (13), is moderately luminescent in H2O by excitation at 395,nm, whereas [Eu3+(minocycline-DTPA)] (9) was not luminescent by excitation at the same wavelength. The luminescence and the excitation spectra of [Eu3+(minocycline-TTHA)] (13) showed that, different from other luminescent EuIII chelate complexes, the emission at 615,nm is caused via direct excitation of the Eu3+ ion, and the chelate ligand is not involved in the excitation of Eu3+. However, the ligand seems to act for the prevention of quenching of the Eu3+ emission by H2O. The fact that the excitation spectrum of [Eu3+(minocycline-TTHA)] is almost identical with the absorption spectrum of Eu3+ aqua ion supports such an excitation mechanism. The high stability of the complexes of [Eu3+(minocycline-DTPA)] (9) and [Eu3+(minocycline-TTHA)] (13) was confirmed by UV-absorption semi-quantitative titrations of H4(minocycline-DTPA) (8) and H5(minocycline-TTHA) (12) with Eu3+. The titrations suggested also that an 1,:,1 ligand Eu3+ complex is formed from 12, whereas an 1,:,2 complex was formed from 8 minocycline-DTPA. The H5(minocycline-TTHA) (12) was successfully conjugated to streptavidin (SA) (Scheme,5), and thus the applicability of the corresponding Eu3+ complex to label a protein was established. [source] Formation of Europium Chelate Complexes by Vacuum Co-Deposition and Their Application in Organic Light-Emitting Diodes,ADVANCED MATERIALS, Issue 13 2004T. Oyamada A unique method of material synthesis based on vacuum co-deposition is reported. A Eu complex was formed by co-deposition of bis(dipivaloymethanato)europium (Eu(DPM)3) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), which both showed excellent volatility during vacuum deposition. Photoexcitation of the BCP led to intense emission from the Eu3+ ions, verifying efficient exciton energy transfer and therefore complex formation. [source] ChemInform Abstract: Copper(I) Chelate Complexes with Novel ,-Conjugated 1,2-Bis(2-pyridylethynyl)benzene Ligands: Synthesis, Structure, and Reactivity.CHEMINFORM, Issue 19 2002Tomikazu Kawano Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Synthesis, Coordination and Catalytic Utility of Novel Phosphanyl,ferrocenecarboxylic Ligands Combining Planar and Central ChiralityEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2007Martin Lama Abstract The chiral ferrocene derivative (R,Rp)-2-[1-(diphenylphosphanyl)ethyl]ferrocenecarboxylic acid (1) is prepared together with selected derivatives resulting from modification at the phosphane moiety [P -oxide (5) and P -sulfide (4)] and the carboxyl group {amides bearing benzyl (6) and (R)- or (S)-1-phenylethyl substituents [(R)- 7 and (S)- 7] at the amide nitrogen atom}. Acid 1 and amide 6 are studied as ligands in rhodium and palladium complexes. Bridge cleavage of the dimer [{Rh(,-Cl)Cl(,5 -C5Me5)}2] with 1 gives [RhCl2(,5 -C5Me5)(1 -,P)] (9) containing P-monodentate 1, which undergoes smooth conversion to the (phosphanylalkyl)ferrocenecarboxylato complex [RhCl(,5 -C5Me5){Fe(,5 -C5H5)(,5 -C5H3 -1-CH(Me)PPh2 -2-COO-,2O,P}] (10) upon treatment with silica gel or alumina. Yet another O,P -chelate complex,[Rh{Fe(,5 -C5H5)(,5 -C5H3 -1-CH(Me)PPh2 -2-COO-,2O,P}(CO)(PCy3)] (11; Cy = cyclohexyl) is obtained directly by an acid-base reaction between the acetylacetonato complex [Rh(acac)(CO)(PCy3)] and 1. Amide 6 reacts with [{Pd(,-Cl)(,3 -C3H5)}2] to give the expected phosphane complex [PdCl(,3 -C3H5)(6 -,P)] (12), while the replacement of the cyclooctadiene (cod) ligand in [PdCl(Me)(cod)] affords the chelate complex [PdCl(Me)(6 -,2O,P)] (13). All compounds are characterised by spectroscopic methods and the solid-state structures of 5, 9, 11, 13, (R,Sp)-2-[1-(diphenylphosphoryl)ethyl]-1-[N -(R)-(1-phenylethyl)carbamoyl]ferrocene [(R)- 8; phosphane oxide from (R)- 7], and the synthetic precursors (R,Sp)-1-bromo-2-[1-(diphenylphosphanyl)ethyl]ferrocene (2) and (R,Sp)-1-bromo-2-[1-(diphenylthiophosphoryl)ethyl]ferrocene (3) determined by single-crystal X-ray diffraction. The catalytic properties of 1 and the amides are probed in enanatioselective rhodium-catalysed hydrogenation and palladium-catalysed asymmetric allylic alkylation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] 1,3,6-Azadiphosphacycloheptanes: A novel type of heterocyclic diphosphinesHETEROATOM CHEMISTRY, Issue 2 2008Andrey A. Karasik The novel type of seven-membered cyclic diphosphines, namely 1,3,6-azadiphosphacycloheptanes, has been synthesized by condensation of 1,2-bis(phenylphosphino)ethane, formaldehyde, and primary amines (aniline, p -toluidine, benzylamine, and 5-aminoisophthalic acid) as a mixture of rac- and meso-stereoisomers. The structures of rac-stereoisomers of N -tolyl and N -(3,,5,-dicarboxyphenyl)-substituted diphosphines were investigated by X-ray crystal structure analyses. The stereoisomers of N -(3,,5,-dicarboxyphenyl)-substituted compound were separated at a preparative scale, and their platinum(II) dichloride complexes were obtained. The corresponding meso-isomer readily forms P,P -chelate complex with [PtCl2(cod)], whereas the rac-stereoisomer forms oligomeric complex. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:125,132, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20397 [source] Oxidative addition of different electrophiles with rhodium(I) carbonyl complexes of unsymmetrical phosphine,phosphine monoselenide ligandsAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2006Pratap Chutia Abstract Dimeric chlorobridge complex [Rh(CO)2Cl]2 reacts with two equivalents of a series of unsymmetrical phosphine,phosphine monoselenide ligands, Ph2P(CH2)nP(Se)Ph2 {n = 1(a), 2(b), 3(c), 4(d)}to form chelate complex [Rh(CO)Cl(P,Se)] (1a) {P,Se = ,2 -(P,Se) coordinated} and non-chelate complexes [Rh(CO)2Cl(P,Se)] (1b,d) {P,Se = ,1 -(P) coordinated}. The complexes 1 undergo oxidative addition reactions with different electrophiles such as CH3I, C2H5I, C6H5CH2Cl and I2 to produce Rh(III) complexes of the type [Rh(COR)ClX(P,Se)] {where R = C2H5 (2a), X = I; R = CH2C6H5 (3a), X = Cl}, [Rh(CO)ClI2(P,Se)] (4a), [Rh(CO)(COCH3)ClI(P,Se)] (5b,d), [Rh(CO)(COH5)ClI-(P,Se)] (6b,d), [Rh(CO)(COCH2C6H5)Cl2(P,Se)] (7b,d) and [Rh(CO)ClI2(P,Se)] (8b,d). The kinetic study of the oxidative addition (OA) reactions of the complexes 1 with CH3I and C2H5I reveals a single stage kinetics. The rate of OA of the complexes varies with the length of the ligand backbone and follows the order 1a > 1b > 1c > 1d. The CH3I reacts with the different complexes at a rate 10,100 times faster than the C2H5I. The catalytic activity of complexes 1b,d for carbonylation of methanol is evaluated and a higher turnover number (TON) is obtained compared with that of the well-known commercial species [Rh(CO)2I2],. Copyright © 2006 John Wiley & Sons, Ltd. [source] Dynamic Stereochemical Behaviour of Congested Ruthenium(II) Complexes Containing Asymmetric Thioether Ligands Based on Pyridine and PyrimidineEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 30 2008Giuseppe Tresoldi Abstract The asymmetric thioethers L [L = 2-pyridylmethyl 2,-pyrimidyl sulfide (pps) and 2-(4-methylpyrimidyl) 2,-pyridylmethyl sulfide (mps)] reacted with cis -[RuCl2(N,N -L,)2] [L, = di-2-pyridyl sulfide (dps); 2,2,-bis(4-methylpyridyl) sulfide (4mdps); 2,2,-bis(5-methylpyridyl) sulfide (5mdps)] to give the five-membered-ring chelate complexes [Ru(N,N -L,)2(Npyridine,S -L)]++ as the major products (92,95,%). Because the sulfur and ruthenium atoms are stereogenic centres, with (R) and (S) and , and , configurations, respectively, four isomers, including the enantiomers were obtained. At low temperature and in the methylene region of the 1H NMR spectra, two AB systems due to the enantiomer couples ,S ,R (a) and ,R ,S (b) were observed with abundances of 77,89 and 6,18,%, respectively. Furthermore, NMR spectroscopic investigations showed that the hybrid polydentate ligands L change their coordination mode. Thus, although a and b largely predominate, a mixture of species containing L and the Ru(N,N -L,)2 unit in the ratio 1:1 are present. The four-membered-ring chelate complexes [Ru(N,N -L,)2(Npyrimidine,S -L)]++ (c), as minor species (abundance 1,8,%), are always observed, whereas the dinuclear species [{Ru(N,N -L,)2}2(,-L)2]+4 (d, e) are observed when L, = dps or 5mdps. In these cases, four AB systems are assigned to dinuclear species d and e containing two bridging L that act as Npyridine,S- or Npyridine,Npyrimidine -donor ligands. The 1H NMR spectra are temperature dependent in that at low temperature the complexes undergo inversion of the chiral centre of the coordinated sulfur atom (a [rlhar2] b) and the dimer (d, e) and monomer (c) are in equilibrium; at higher temperatures the complexes undergo a structural dynamic rearrangement, which involves exchange between the coordinated and uncoordinated N atoms (b [rlhar2] c). One-dimensional band-shape analysis of the exchanging methylene and methyl proton signals showed that the energy barriers for inversion of the sulfur centre are in the 50,53 kJ,mol,1 range, whereas those for the higher-temperatures process are in the 62,68 kJ,mol,1 range. The possible mechanisms of the processes are discussed. NMR spectroscopic findings suggest that inversion at the sulfur centre occurs without any bond rupture, whereas the exchange, at higher temperatures (b [rlhar2] c), is a dissociative process involving the breaking of a Ru,Npyridine bond.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Diastereomeric Halfsandwich Rhenium Complexes Containing Hemilabile Phosphane LigandsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 24 2004Stefan Dilsky Abstract The syntheses and some typical reactions of diastereomeric rhenium complexes [CpRe(NO)(CO){P(Ph)(R)(R,)}]BF4 (R = Me, Ph; R, = 2-C6H4OMe, CH2C4H3S, CH2C4H7O) (3a,e) are described. Reduction of the carbonyl ligand with NaBH4 in THF gave the corresponding methyl complexes [CpRe(NO){P(Ph)(R)(R,)}(CH3)] (4a,e). Acid treatment of the methyl complexes leads to liberation of methane and coordination of the additional donor site of the potentially bidentate phosphane ligand. Of the chelate complexes 5a,e, those with R, = 2-C6H4OMe (5a, d) decomposed in solution at room temperature. In donor solvents, the chelate ring opens giving the stable solvated complexes [CpRe(NO){P(Ph)(R)(R,)}](solvent)]BF4 (solvent = CH3CN, THF) (6b,e, 7d). The new compounds are thus suitable starting materials for the syntheses of diastereomeric rhenium complexes [CpRe(NO){P(Ph)(R)(R,)}(L)]BF4. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Structure Comparison of Early and Late Lanthanide(III) Homodinuclear Macrocyclic Complexes with the Polyamine Polycarboxylic Ligand H8OHECEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2004Ulrike A. Böttger Abstract The solid-state structures of two new homodinuclear chelate complexes with the late lanthanide(III) ions Yb and Lu, [Na2(Yb2OHEC)].14.5H2O (1), and [Na2(Lu2OHEC)].14.5H2O (2) (H8OHEC = 1,4,7,10,14,17,20,23-octaazacyclohexacosane- 1,4,7,10,14,17,20,23-octaacetic acid), have been determined by X-ray crystal structure analysis. Each lanthanide(III) ion is coordinated by eight donor atoms of the ligand and the geometry of the coordination polyhedron approaches a bicapped trigonal prism. These structures are compared with those of the homodinuclear chelate complexes with the same ligand and the mid to early lanthanide(III) ions Gd, Eu, La and also Y. A distinctive structural change occurs across the lanthanide series. The centrosymmetric mid to early lanthanide(III) complexes are all ninefold-coordinated in a capped square antiprismatic arrangement with a water molecule coordinated in a prismatic position. This structure is maintained in aqueous solution, together with an asymmetric minor isomer. The late lanthanide(III) OHEC complexes not only lack the inner-sphere water, but the change of coordination sphere also results in a loss of symmetry of the whole complex molecule. The observed change of coordination mode and number of the lanthanide ion may offer a geometric model for the isomerization process in eight- and ninefold-coordinated complex species that are isomers in a possible coordination equilibrium observed by NMR in aqueous solution. This model may also explain the intramolecular rearrangements necessary during water exchange in the inner coordination sphere of the complex [(Gd2OHEC)(H2O)2]2, through a slow dissociative mechanism. Protonation constants of the H8OHEC ligand and complex formation constants of this ligand with GdIII, CaII, CuII and ZnII have been determined by solution thermodynamic studies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Minocycline-Based Europium(III) Chelate Complexes: Synthesis, Luminescent Properties, and Labeling to StreptavidinHELVETICA CHIMICA ACTA, Issue 11 2009Takuya Nishioka Abstract Two chelate ligands for europium(III) having minocycline (=(4S,4aS,5aR,12aS)-4,7-bis(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxonaphthacene-2-carboxamide; 5) as a VIS-light-absorbing group were synthesized as possible VIS-light-excitable stable Eu3+ complexes for protein labeling. The 9-amino derivative 7 of minocycline was treated with H6TTHA (=triethylenetetraminehexaacetic acid=3,6,9,12-tetrakis(carboxymethyl)-3,6,9,12-tetraazatetradecanedioic acid) or H5DTPA (=diethylenetriaminepentaacetic acid=N,N -bis{2-[bis(carboxymethyl)amino]ethyl}glycine) to link the polycarboxylic acids to minocycline. One of the Eu3+ chelates, [Eu3+(minocycline-TTHA)] (13), is moderately luminescent in H2O by excitation at 395,nm, whereas [Eu3+(minocycline-DTPA)] (9) was not luminescent by excitation at the same wavelength. The luminescence and the excitation spectra of [Eu3+(minocycline-TTHA)] (13) showed that, different from other luminescent EuIII chelate complexes, the emission at 615,nm is caused via direct excitation of the Eu3+ ion, and the chelate ligand is not involved in the excitation of Eu3+. However, the ligand seems to act for the prevention of quenching of the Eu3+ emission by H2O. The fact that the excitation spectrum of [Eu3+(minocycline-TTHA)] is almost identical with the absorption spectrum of Eu3+ aqua ion supports such an excitation mechanism. The high stability of the complexes of [Eu3+(minocycline-DTPA)] (9) and [Eu3+(minocycline-TTHA)] (13) was confirmed by UV-absorption semi-quantitative titrations of H4(minocycline-DTPA) (8) and H5(minocycline-TTHA) (12) with Eu3+. The titrations suggested also that an 1,:,1 ligand Eu3+ complex is formed from 12, whereas an 1,:,2 complex was formed from 8 minocycline-DTPA. The H5(minocycline-TTHA) (12) was successfully conjugated to streptavidin (SA) (Scheme,5), and thus the applicability of the corresponding Eu3+ complex to label a protein was established. [source] FTIR Microanalysis and Phase Behaviour of Ethylene/1-Hexene Random CopolymersMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 14 2007Mariano Pracella Abstract Ethylene/1-hexene random copolymers with 1-hexene content in the range of 1,5 mol-%, synthesised in the presence of new heterogeneous catalyst systems based on bis-carboxylato and -bis-chloro-carboxylato titanium chelate complexes, have been characterised by FTIR microspectroscopy (FTIR-M), DSC calorimetry and X-ray scattering. The co-monomer content and sequence distribution in the various samples were determined by means of both FTIR-M and 13C NMR spectroscopy. The deformation bands of methyl groups in the region of 1,400,1,330 cm,1 were used for the structural analysis of these copolymers. The effect of composition on the crystallinity and phase transitions of copolymers was analysed both in 1,500,1,300 and 760,690 cm,1 frequency ranges as a function of the annealing temperature. A neat variation of the absorbance ratio of methyl band at 1,378 cm,1 was recorded between 110 and 130,°C corresponding to the melting range of the copolymer crystals. The crystallisation behaviour of the copolymers was examined by DSC in dynamic and isothermal conditions; the isothermal kinetics were analysed according to the Avrami model. A marked decrease in the bulk crystallisation rate, accompanied by changes in the nucleation and growth of crystals, was found with an increase in the co-monomer content. The melting behaviour of isothermally crystallised samples was also investigated and the melting temperatures of the copolymers at equilibrium conditions were related to the composition; the experimental data were consistent with the Flory exclusion model of side branches from the crystalline phase. The lowering of crystal growth rate in the copolymers has been accounted for by an increase in the free energy of formation of critical size nuclei due to the effect of the side branches. [source] Synthesis and characterizations of N,N,-bis(diphenylphosphino)-2-(aminomethyl)aniline derivatives: application of a palladium(II) complex as pre-catalyst in Heck and Suzuki cross-coupling reactionsAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 3 2009Murat Aydemir Abstract The reaction of 2-(aminomethyl)aniline with 2 equivalents of PPh2Cl in the presence of Et3N, proceeds in CH2Cl2 to give N,N,-bis(diphenylphosphino)-2-(aminomethyl)aniline 1 in good yield. Oxidation of 1 with aqueous H2O2, elemental sulfur or gray selenium gave the corresponding oxide, sulfide and selenide dichalcogenides [Ph2P(E)NHC6H4CH2NHP(E)Ph2] (E: O, 2a; S, 2b; Se, 2c), respectively. The reaction of [Ph2PNHC6H4CH2NHPPh2] with PdCl2(cod), PtCl2(cod) and [Cu(MeCN)4]PF6 gave the corresponding chelate complexes, PdCl21, PtCl21 and [Cu(1)2]PF6. The new compounds were fully characterized by NMR, IR spectroscopy and elemental analysis. The catalytic activity of the Pd(II) complex was tested in the Suzuki coupling and Heck reactions. The Pd(II) complex catalyzes the Suzuki coupling and Heck reaction, affording biphenyls and stilbenes respectively, in good yields. Copyright © 2009 John Wiley & Sons, Ltd. [source] Microsolvated and Chelated Butylzinc Cations: Formation, Relative Stability, and Unimolecular Gas-Phase ChemistryCHEMISTRY - A EUROPEAN JOURNAL, Issue 46 2009Julia Abstract Solutions of butylzinc iodide in tetrahydrofuran, acetonitrile, and N,N -dimethylformamide were analyzed by electrospray ionization mass spectrometry. In all cases, microsolvated butylzinc cations [ZnBu(solvent)n]+, n=1,3, were detected. The parallel observation of the butylzincate anion [ZnBuI2], suggests that these ions result from disproportionation of neutral butylzinc iodide in solution. In the presence of simple bidentate ligands (1,2-dimethoxyethane, N,N -dimethyl-2-methoxyethylamine, and N,N,N,,N, -tetramethylethylenediamine), chelate complexes of the type [ZnBu(ligand)]+ form quite readily. The relative stabilities of these complexes were probed by competition experiments and analysis of their unimolecular gas-phase reactivity. Fragmentation of mass-selected [ZnBu(ligand)]+ leads to the elimination of butene and formation of [ZnH(ligand)]+. In marked contrast, the microsolvated cations [ZnBu(solvent)n]+ lose the attached solvent molecules upon gas-phase fragmentation to produce bare [ZnBu]+, which subsequently dissociates into [C4H9]+ and Zn. This difference in reactivity resembles the situation in organozinc solution chemistry, in which chelating ligands are needed to activate dialkylzinc compounds for the nucleophilic addition to aldehydes. [source] Three-Component Entanglements Consisting of Three Crescent-Shaped Bidentate Ligands Coordinated to an Octahedral Metal CentreCHEMISTRY - A EUROPEAN JOURNAL, Issue 31 2007Fabien Durola Abstract 3,3,-Biisoquinoline ligands (biiq) L, bearing aromatic substituents on their 8 and 8, positions, have been used to generate interwoven systems consisting of three crescent-shaped ligands disposed around an octahedral metal centre. Mono-ligand complexes of the type [ReL(CO)3py]+ (py: pyridine) have also been prepared, leading to sterically non-hindering complexes in spite of the endotopic nature of the chelate used. The three-component entanglements have been prepared by using either FeII or RuII as gathering metal centre. The synthetic procedure is simple and efficient, affording fully characterised complexes as their PF6 or SbCl6 salts. X-ray crystallography clearly shows that the crescent-shaped ligands do not repel each other in the tris-chelate complexes. In an analogous way, the ReI complexes show open structures with no steric repulsion between the L ligand and the ancillary CO or py groups. The FeL3 or RuL3 compounds are very unusual in the sense that, contrary to all the other tris-bidentate chelate complexes made till now, the three organic components are tangled up, in a situation which will be very favourable to the formation of new non trivial topologies of the catenane type. [source] | |||||||||||||||||||||||||