Compound Mer Research Articles

Tuning of cytotoxic activity by bio-mimetic ligands in ruthenium nitrosyl complexes

Three novel ruthenium nitrosyl complexes [Ru(NO)Cl3(InicMe)2] (1b), [RuNOCl3(NicEt)2] (1c) and [RuNOCl3(NicMe)2] (1d) (InicMe = methyl isonicotinate, NicEt = ethyl nicotinate, NicMe = = methyl nicotinate)were prepared and crystal structure of the complexes were determined by single crystal XRD analysis. In all complexes, the organic ligands are coordinated by a pyridine nitrogen atom and located in trans-position each to other and in cis-position to NO group. In the crystal package of all compounds stacking interactions of two types were determined: πarene-πarene and πCOO-πarene stacking. Finally, cytotoxicity of the compounds was tested on Hep2 and HepG2 cell lines. In the set of similar compounds mer-[RuNO(L)2Cl3] (L = Py, γ-Pic, β-Pic, Inic-Alk, Nic-Alk), complexes with iso-nicotinic acid esters are the most toxic, while nicotinic acid derivatives are less toxic and compared with pyridine complex.

Analyzing Ru(III)–dmso and Ru(III)–dms motifs in compounds used in the synthesis of the antimetastatic agents

The chemistry of Ru(III) complexes containing dmso as a ligand has become an interesting area in the cancer treatment field. Because of this, structural knowledge and chemistry of the moiety Ru(III)–dmso have become important to cancer research. The crystal structures of the compounds mer-[RuCl 3(dms) 3] ( 1) and mer-[RuCl 3(dms) 2(dmso)]: mer-[RuCl 3(dms) 3] ( 2) were determined by X-ray crystallography and a speciation of the presence of intramolecular hydrogen bond in these structures has been studied. Compound ( 1) crystallizes in the orthorhombic space group, Pna2 1; a = 16.591(8) Å, b = 8.724(2) Å, c = 10.547(3) Å; Z = 12 and ( 2) crystallizes in the space group, P2 1/C; a = 11.9930(2) Å, b = 7.9390(2) Å, c = 15.8700(3) Å, β = 93.266(1)°, Z = 2. From the X-ray structures solved in this work, were possible to suggest an interpretation for the broad lines observed in the EPR spectra of the Ru(III) compounds explored here. Also, the exchange interactions detected by EPR spectroscopy in solid state and in solution, confirm the presence of van der Waals interactions such as C–H…Cl in the compounds ( 1), ( 2) and ( 3). The use of techniques such as IR, UV–vis, 1H NMR and EPR Spectroscopy and Cyclic Voltammetry were applied in this work to analyze the behavior of these metallocompounds.

Reactivity of rhodium(III) complexes containing chelating pentachlorophenyl ligands. Molecular structures of fac-[Rh(C 6Cl 5) 3(py)] and mer-[Rh(C 6Cl 5) 3( tBuNC) 3

The reactions of the octahedral rhodium(III) complexes [Rh(C 6Cl 5) 3] and [Rh(C 6Cl 5) 3Cl] − with neutral monodentate ligands have been studied. With pyridine, triethylphosphine or pyrazole, one of the rhodium o-chloro bonds of the starting materials is broken and complexes of formula [Rh(C 6Cl 5) 3L] and [Rh(C 6Cl 5) 3ClL] − are obtained. Carbonylation of [Rh(C 6Cl 5) 3] produces the insertion of CO molecules in two of the RhC aryl bonds giving the diacyl complex [Rh{C(O)C 6Cl 5} 2(C 6Cl 5)(CO)], while the reaction of [Rh(C 6Cl 5) 3] or [Rh(C 6Cl 5) 3Cl] − with the strong σ-donor ligand t BuNC breaks all the rhodium o-chloro interactions producing the compound mer-[Rh(C 6Cl 5) 3( t BuNC) 3]. All the complexes are stable to the air and moisture in the solid state and moderately stable in deoxygenated solutions. The compounds have been studied and characterised by IR, NMR and MS. The crystal structures of fac-[Rh(C 6Cl 5) 3(py)] and mer-[Rh(C 6Cl 5) 3( t BuNC) 3] have been determined by X-ray diffraction methods. They display distorted octahedral metal environments but, while the pyridine complex shows two C 6Cl 5 groups acting as chelate ligands bonded through the ipso-C atom and one of the o-Cl atoms, the isocyanide complex exhibits all the coordinated ligands acting as monodentate groups.

Unusual pathways for the reaction between [MCl2(Me2SO)4] (M = Os, Ru) and hydrazine dihydrochloride: deoxygenation of sulfoxides vs. coordination of hydrazinium

Reaction of trans-[OsCl2(Me2SO)4] 1 with excess N2H4·2HCl leads to the osmium(III) compound mer-[OsCl3(NH3)2(Me2S)] 2 in the course of concerted reactions, i.e. oxidation of the metal, deoxygenation of the sulfoxide, disproportionation of hydrazine and substitution by NH3. In contrast, interaction of cis-[RuCl2(Me2SO)4] cis-3 with hydrazine dihydrochloride brings about easy substitution (without redox conversion) leading to mer-[RuCl3(N2H5)(Me2SO)2] 4 which is a rare example of a hydrazinium complex. X-Ray single-crystal diffraction analyses were performed on 1, 2 and 4. In 4, one Ru–S bond is unusually short due to the enhanced π bonding contribution as a result of an intramolecular H-bond between the Me2SO and the cis N2H5+ group. The complexes show anodic oxidations and 4, that in aqueous medium undergoes spontaneous dehydrochlorination, exhibits by controlled potential electrolysis a multi-electron oxidation process with anodically-induced H+ loss, oxidation of the hydrazine ligand to N2 and N-oxides, and of Me2SO to SO2. The anodic waves of Me2SO or H2O solutions of cis-3 were assigned to trans-[RuCl2(Me2SO-S)4] trans-3 and [RuCl(H2O)2(Me2SO-S)3]+, respectively. The oxidation potential values were interpreted on the basis of redox potential–structure relationships and the Lever electrochemical parameter EL was tentatively estimated for both S- and O-coordinated Me2SO and for the hydrazinium ligand, showing that Me2SO-S in our complexes behaves as a significant π-electron acceptor and N2H5+ as a rather weak net electron donor, and applied to predict the oxidation potential of some Ru and Os complexes.

The phenomenon of conglomerate crystallization: Part 52. Stereochemical control of the crystallization pathway by small alterations of ligands

The X-ray structure analysis of mer- trans-[Co(aepn)Cl 2(OH 2)](ClO 4)·H 2O ( 1) (aepn= N-(2-aminoethyl)-1,3-propanediamine) reveals that the compound crystallizes in an enantiomorphic space group P2 12 12 1 implying a spontaneous resolution of its racemic solution, known as conglomerate crystallization. Substitutions of the two chloride ligands with bromides result in the isostructural compound mer- trans-[Co(aepn)Br 2(OH 2)](ClO 4)·H 2O ( 2), which also crystallizes as a conglomerate in the space group P2 12 12 1. Meanwhile, a substitution of the coordinated OH 2 of 1 with NH 3 gives mer- trans-[Co(aepn)Cl 2(NH 3)](ClO 4) ( 3), which crystallizes as a simple racemate in P2 1/ n space group. When N-(3-aminopropyl)-1,3-propanediamine (dpt) is used instead of aepn in the preparation of 1, it gives racemic crystals of mer- trans-[Co(dpt)Cl 2(OH 2)](ClO 4) ( 4) whose molecular packing pattern is identical to that of 3. In the conglomerate structures, the protons of coordinated water ligand are strongly hydrogen-bonded to the oxygen of a water of crystallization to form a spiral packing structures. In the packing structures of 3 and 4, two molecules of opposite chirality are brought together around a crystallographic center of inversion by hydrogen bonds of the protons of the corresponding tridentate amine ligand with oxygens of perchlorate anion.

Mer-[Ru(terpy)Cl 3] (terpy = 2,2′:6′,2″-terpyridine) shows biological activity, forms interstrand cross-links in DNA and binds two guanine derivatives in a trans configuration

The compound mer-[Ru(terpy)Cl 3] was found to be active as a cytostatic in L1210 leukemia cells, with an activity in between cisplatin and carboplatin. It was shown that the Ru complex covalently binds to DNA and this binding results in the formation of ∼2% interstrand cross-links. In addition, no Ru-promoted nicks are formed. The parent compound has also been reacted with the DNA model bases 9-methylhypoxanthine (9mhyp) and 9-ethylguanine (9egua). The solid complexes trans-[Ru(terpy)(B- κN 7) 2(H 2O)](PF 6) 2, where B = 9mhyp or 9egua, were isolated and characterized in acetone solution by proton NMR. The bases are symmetrically arranged around the metal center, and involved in hydrogen bonding with the water ligand, most likely via their O6 atoms. The water ligand has been substituted by acetonitrile. The complexes trans-[Ru(terpy)(B- κN 7) 2(CH 3CN)](PF 6) 2, where B = 9mhyp or 9egua, have been prepared in situ. Compared to the aqua complexes, the hydrogen bond donor molecule is lost and a rearrangement of the guanine bases is observed.

Synthese und Reaktionen von oktaedrischen Boranatoruthenium(II)-Komplexen / Synthesis and Reactions of Octahedral Boranatoruthenium(II) Complexes

The boranato(hydrido) ruthenium(II) complex mer-[RuH(η2-H2BH2)(PMe3)3] (4) is prepared from trans-[RuCl2(PMe3)4], NaBH4 and methanol. Compound 4 reacts with CO/NEt3, PMe3, HON=CHCH3 and CH3OH/H2 by elimination of BH3 to give the octahedral complexes cis/mer-[RuH2(CO)(PMe3)3] (5), cis-[RuH2(PMe3)4] (2), mer-[RuH(η2-ON=CHCH3)(PMe3)3] (6) and cis/mer-[RuH2(η2-H2)(PMe3)3] (7), respectively. The reaction of 4 with alkynes HC≡CR (R = H, Me, Ph, tBu) and RC≡CCO2Me (R = Me, CO2Me) leads to the formation of the insertion products mer-[Ru(E–CH=CHR)(η2-H2BH2)(PMe3)3] (9, 10a, 11,12), mer-[Ru(CMe=CH2)(η/2-H2BH2)(PMe3)3] (10b), mer-[Ru(C(CO2Me)=CHC(OMe)=O)(η1-HBH3)(PMe3)3] (14) and mer-[Ru(CMe=CHCO2Me)(η2-H2BH2)(PMe3)3] (15). From 4 and HC≡CCO2Me, the alkynyl ruthenium(II) compound mer-[Ru(C≡CCO2Me)(η2-H2BH2)(PMe3)3] (13) is obtained. The alkenyl complex 11 (R = Ph) reacts with phenylacetylene in the molar ratio 1:1 to give mer-[Ru(C≡CPh)(η2-H2BH2)(PMe3)3] (16) whereas with excess PhC≡CH the bis(alkynyl) compound trans-[Ru(C≡CPh)2(PMe3)4] (17) is formed. Treatment of 11 with 2 equivalents of PMe3 affords cis-[RuH(E–CH=CHPh)(PMe3)4] (20) which reacts with CHCl3 to yield an isomeric mixture of cis/trans-[RuCl(E–CH = CHPh)(PMe3)4] (22a, b). Attempts to prepare the vinylidene ruthenium(O) complex [Ru(=C=CHPh)(PMe3)4] by HCl elimination from 22a failed.

Chemistry of (Carbonyl)(nitrosyl)[bis(phosphorus donor)]rhenium Complexes

AbstractThe chemistry of [Re(CO)(NO)L2] fragments (L  phosphorus donor) was explored. Starting from [Re(CO)5Cl] the synthesis of [Re2Cl2(μ‐Cl)2(CO)4(NO)2] (1) was accomplished via the preparation of [Et4N]2[Re2Cl2(μ‐Cl)2(CO)6] and nitrosylation of this compound with [NO][BF4]. Complex 1 was converted to [RecL2(CO)(NO)L2] complexes 2 (a L = (MeO)3P; b L = (EtO)3P; c L = (i‐PrO)3P; d L  Me3P; e L  Et3P; f L  Cy3P) by heating with L in MeCN. In the case of the reaction of L = (MeO)3P, a trisubstitued compound mer‐{ReCl2(NO)[P(OMe)3]3} 3 was also obtained. Replacement of the Cl ligands in 2a–e with Me groups was achieved by reacting them with MeLi in Et2O yielding cis, trans‐[Re(CO)(NO)Me2L2]complexes 4a–e. Reaction of 2a–e with Li[BHEt3] led to substitution of one Cl by an H ligand with formation of [ReCl(CO)H(NO)L2] compounds 5a–;e, displaying trans‐H,NO geometries. The hydride‐transfer agent Na[AlH2(OCH2CH2OCH3)2] transformed 2 into the cis‐dihydride systems [Re(CO)H2(NO)L2] 6a–f. Reductive carbonylation of 2a–d in the presence of Na/Hg and CO gave pentacoordinate [Re(CO)2(NO)L2] complexes 7b–d, and under comparable conditions the Cl substituents of 2b–f were replaced by tolane using Mg or t‐BuLi giving trigonal bipyramidal [Re(CO)(NO)L2(PhCCPh)] compounds 8b–f. Complexes 5c, 6a, and 8d were characterized by X‐ray crystal‐structure analysis.

Synthesis of monomeric, oligomeric and polymeric σ-acetylide complexes of platinum, palladium, nickel and rhodium

Reaction of equimolar quantities of Me 3SnCCRCCSnMe 3 [R = p-C 6H 4; p-C 6H 2(CH 3)2; p-C 6H 4- p-C 6H 4] with the group 10 metal dihalide complexes, [M(X nBU 3) 2Cl 2] (M = Pt, Pd, Ni; X = P, As; Bu = butyl) affords the polymeric species trans-[−M(X nBU 3) 2(-CCRCC-)] n in excellent yields. By varying the stoichiometry of these reactions, complexes of the type trans-[M(X nBU 3) 2(−CCRCCSnMe 3) 2] and trans-[ClM(X nBU 3) 2CCRCCM(X n BU 3) 2Cl], which are precursors to higher oligomers, can be prepared. Treatment of the former with an excess of trans-[M(X nBU 3) 2Cl 2] affords the trimetallic compound trans-[ClM(X nBU 3) 2(−CCRCC−)M(X nBU 3) 2(−CCRCC−)M(X nBU 3) 2Cl], while reaction of the latter with two equivalents of Me 3SnCCRCCSnMe3 followed by two equivalents of trans-[M(X nBu 3) 2Cl 2] gives the complex trans-[ClM(X nBU 3) 2(−CCRCC−)M(X nBu 3) 2(−CCRCC−)M(X nBu 3) 2(−CCRCC−)M(X nBu 3) 2Cl]. Treatment of the complex [Rh(PPhl) 3Cl] (Ph = Phenyl) with one equivalent of Me 3SnCCRCCSnMe 3 [R = p-C 6H 4- p-C 6H 4] gives the polymeric species [−Rh(PPh 3) 2(SnMe 3)(−CCRCC−)] n . Model compounds for other rhodium-containing σ-acetylide complexes have been obtained from the reaction between the complex [Rh(PMe 3) 4Cl] (Me = CH 3) and Me 3SnCCC 6H 5 which yields the compound mer,trans-[Rh(PMe 3) 3-(SnMe 3)(−CCC 6H 5) 2] via the intermediate [Rh(PMe 3) 4(−CH 5]. Reaction of [Rh(PMe 3) 4Cl] with one equivalent of Me 3SnCCRCCSnMe3 [R = p-C 6H 4- p-C 6H 4] yields the polymer mer,trans[−Rh(PMe 3) 3(SnMe 3)(−CCRCC−)] n .

Vinyliden‐übergangsmetallkomplexe, XVII. Synthese von trans‐[IrCl(=C=CH2)(PR3)2] (PR3 = PMetBu2, PPh3), [IrHCl(CCPh)(PMe2tBu)3] und einigen Dihydridoiridium(III)‐Komplexen

Vinylidene Transition‐Metal Complexes, XVII. — Synthesis of trans‐[IrCl(=C=CH2)(PR3)2] (PR3 = PMetBu2, PPh3), [IrHCl(CCPh)(PMe2tBu)3], and of some Dihydridoiridium(III) Complexes[IrCl(C8H14)2]2 (1) reacts with PMetBu2 in the presence of H2 to give [IrH2Cl(PMetBu2)2] (2). Treatment of 2 with acetylene yields the vinylidene complex trans‐[IrCl(=C=CH2)‐(PMetBu2)2] (3). The reaction of 1 with PMePh2 or PMe2tBu in the presence of H2 leads to the formation of fac‐[IrH2Cl(PR3)3] (4a, 5a), which on warming to 60°C rearrange to give the more stable mer isomers 4b, 5b. Treatment of 1 with PMePh2 or PMe2tBu and phenylacetylene affords the hydrido(phenyl‐ethynyl)iridium(III) compounds mer‐[IrHCl(CCPh)(PR3)3] (8, 9), which could not be converted by phosphine elimination to the corresponding (phenylvinylidene)iridium complexes. The synthesis of trans‐[IrCl(=C=CH2)(PPh3)2] (11) has been achieved by CO abstraction from [IrHCl(CCH)(CO)(PPh3)2] (13) by using trimethylamine oxide.

Synthesis and structural characterisation of the complex mer-[{Rh(CNC8H9)3(SnCl3)(µ-SnCl2)}2

Compound mer-[{Rh(CNC8H9)3(SnCl3)(µ-SnCl2)}2]1 has been isolated from the reaction of [Rh(CNC8H9)3Cl](CNC8H9= 2,6-xylyl isocyanide) with 2 mol of tin(II) chloride and its molecular structure has been determined by single-crystal X-ray techniques. Compound 1 crystallises in the monoclinic space group P21/n with a= 14.005(3), b= 12.796(4), c= 19.389(3)A, β= 104.96(2)° and Z= 2. The structure of 1 consists of two edge-sharing octahedral rhodium centres linked by two bridging SnCl2 groups. One terminal SnCl3 group and three isocyanide ligands, arranged in mer fashion, complete the co-ordination geometry about each rhodium atom. Tin-119 Mossbauer spectroscopy has been used to investigate the nature of the rhodium–tin bonding interaction in 1.

Synthesis and characterization of technetium(III) complexes with nitrogen heterocycles by oxygen atom transfer from oxotechnetium(V) cores. Crystal structures of mer-[Cl3(pic)3Tc] and mer-[Cl3(pic)(PMe2Ph)2Tc] (pic = 4-picoline). Electrochemical parameters for the reduction of TcII, TcIII, and TcIV

The combination of pyridine ligands, (OCl{sub 4}Tc){sup {minus}}, and O atom acceptors of different cone angles, such as PMe{sub 2}Ph or PPh{sub 3}, results in Tc{sup III} complexes that vary in the coordination of the phosphine ligand. The compounds mer(Cl{sub 3}(4-picoline){sub 3}Tc) and mer-(Cl{sub 3}(4-picoline)(PMe{sub 2}Ph){sub 2}Tc) have been obtained in good yield and have been characterized spectroscopically and by single-crystal x-ray diffraction. The crystal structure data are reported. Linear correlations of technetium reduction potentials in DMF with electrochemical ligand additivity parameters (E{sub L}'s) have been obtained for the Tc{sup II,I}, Tc{sup III,II}, and Tc{sup IV,III} couples. The slope and intercept (S{sub M}, I{sub M}) pairs for each technetium oxidation-reduction couple, respectively, are (1.39, {minus}2.07), (1.29, {minus}0.91), and (1.00, 0.65). 32 refs., 3 figs., 6 tabs.

Co-ordination chemistry of higher oxidation states. Part 8. Nickel(III) complexes of bi- and multi-dentate phosphorus and arsenic ligands; crystal and molecular structure of [Ni(Ph2PCH2CH2PPh2)Br3]·C6H5Me

The five-co-ordinate nickel(III) complexes [Ni(L–L)Cl3][L–L = Ph2PCH2CH2PPh2, Ph2P(CH2)3PPh2, Ph2PCHCHPPh2, o-C6H4(PPh2)2, or Me2PCH2CH2PMe2] have been obtained by Cl2 or NOCl oxidation of [Ni(L–L)Cl2] in CCl4 or CH2Cl2. The bromides [Ni(L–L)Br3][L–L = as above, o-C6H4(AsPh2)2, or o-C6H4(PPh2)(SMe)] are obtained similarly using Br2–CCl4. On gentle heating, [Ni(L–L)X3](X = Cl or Br) lose X2 to reform [Ni(L–L)X2]. Unstable [Ni{o-C6H4(AsMe2)2}X3] have been prepared by halogenation of the dicarbonyl [Ni(CO)2{o-C6H4(AsMe2)2}]. The complexes have been characterised by i.r., electronic, and e.s.r. spectroscopy, and by magnetic measurements, and the structure of [Ni(Ph2PCH2CH2PPh2)Br3]·C6H5Me established by a single-crystal X-ray study. It is monoclinic, space group P21/n, and has a= 15.567(3), b= 14.627(2), c= 15.151(3)A, β= 113.38(2)°, and Z= 4. The structure was refined to R= 0.0562 from 1 583 reflections. The five-co-ordinate nickel is in an approximately square-pyramidal arrangement [Ni–Br 2.346(3), 2.417(3), and 2.363(3); Ni–P 2.223(5) and 2.236(5)A], and lies above the P2Br2 plane toward the apical bromine. The synthesis and properties of pseudo-octahedral [Ni(L′–L′)2X2]Y [L′–L′=o-C6H4(PMe2)2, o-C6H4(AsMe2)(PMe2), o-C6H4(PMe2)(SbMe2), or Me2P(CH2)2PMe2; X = Cl or Br; Y = BF4 or ClO4] are described. The compounds mer-[Ni{PhP(CH2CH2PPh2)2}X3] have also been obtained, but attempts to prepare nickel(III) complexes with quadridentate phosphines were unsuccessful.

Hydride complexes of osmium halides with carbon monoxide, dinitrogen, and tertiary phosphines as co-ligands

The complexes [OsH2Cl2(PR3)3](PR3= PMePh2, PEt2Ph, PEtPh2, or PPhPrn2) have been prepared by the amalgamated-zinc reduction, under dihydrogen, of mer-[OsCl3(PR3)3]. The compounds mer-[OsXY(L)(PR3)3](X = H or D; Y = Cl or Br; L = CO or N2; PR3= PMe2Ph or PEt2Ph) result from mer-[OsY2(L)(PR3)3] by sodium borohydride or lithium aluminium deuteride reduction. The 1H n.m.r. and i.r. spectra of these compounds are recorded and used to assign the configuration of the monohydrido-complexes. The dihydro-complexes react with carbon monoxide, tertiary phosphines and carbon tetrachloride–dichlorine with loss of dihydrogen. With one mole of anhydrous HCl the dihydrido-complexes give the unstable compounds [OsHCl3(PR3)3](PR3= PMePh2 or PEt2Ph) which readily give fac-[OsCl3(PR3)3] and ½H2 when heated. Dinitrogen does not react with [OsH2Cl2(PMePh2)3]. The compound mer-[OsHCl(N2)(PEt2Ph)3] reacts with anhydrous HCl in toluene to give [OsCl2(N2)(PEt2Ph)3] and dihydrogen.