Cyclopentadienyl ruthenium alkynyldithiocarboxylate complexes

Treatment of the ruthenium chloride, CpRu(PPh₃)₂Cl, with the alkynyldithiocarboxylate anions, , in refluxing THF affords the chelate complexes CpRu(PPh₃)(κ²S,S-S₂CCCR) (1) (R = Bu^t (a), Buⁿ (b), Ph (c), SiMe₃ (d)) in high yield. The room temperature reaction of the solvated species, [CpRu(PPh₃)₂(NCPh)]⁺, with the alkynyldithiocarboxylate anions, , produces the chelate complexes 1 and the mono-coordinated complexes CpRu(PPh₃)₂(κS-S₂CCCR) (2). Complexes 2 are converted to 1 in solution so that they were characterized spectroscopically.     

Iridium(I) complex of chelating pyridine-2-thiolate ligand: Synthesis, reactivity, and application to the catalytic E-selective terminal alkyne dimerization via C-H activation

A novel iridium(I) complex bearing a chelate-coordinated pyridine-2-thiolate ligand [Ir(η²-SNC₅H₄)(PPh₃)₂] (2) was prepared by the reaction of iridium ethylene complex [IrCl(C₂H₄)(PPh₃)₂] (1) with lithium salt of pyridine-2-thiol (Li[SNC₅H₄]). On the treatment of iridium(I) complex 2 with chloroform, iridium(III) dichloro-complex [IrCl₂(η²-SNC₅H₄)(PPh₃)₂] (3) was formed. Reactions of complex 2 with methyldiphenylsilane, acetic acid, and p-tolylacetylene afforded iridium(III) hydride complexes [IrH(SiMePh₂)(η²-SNC₅H₄)(PPh₃)₂] (4), [IrH(O₂CCH₃)(η²-SNC₅H₄)(PPh₃)₂] (5), and [IrH(CC(p-tolyl))(η²-SNC₅H₄)(PPh₃)₂] (6), respectively. Complex 2 catalyzed dimerization of terminal alkynes leading to enynes (7) with high E-selectivity via C-H bond activation.     

Tethered silyl complexes from nucleophilic substitution reactions at the Si-Cl bond of the chloro(diphenyl)silyl ligand in Ru(SiClPh2)(κ-S2CNMe2)(CO)(PPh3)2

Crystal structure determination of RuH(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (1) confirms that the triphenylphosphine ligands are arranged mutually trans. 1 reacts readily with HSiClPh₂ to eliminate H₂ and produce the six-coordinate silyl complex, Ru(SiClPh₂)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (2). Crystal structure determination of 2 reveals the same geometrical arrangement of ligands as in 1 with the silyl ligand replacing the hydride ligand. The chloride bound to silicon in 2 is replaced through reactions with 2-hydroxypyridine, 2-aminopyridine, and thallium acetate, producing, respectively, the mono-PPh₃ complexes, Ru(κ²(Si,N)-SiPh₂OC₅H₄N)(κ²-S₂CNMe₂)(CO)(PPh₃) (3), Ru(κ²(Si,N)-SiPh₂NHC₅H₄N)(κ²-S₂CNMe₂)(CO)(PPh₃) (4), and Ru(κ²(Si,O)-SiPh₂OCMeO)(κ²-S₂CNMe₂)(CO)(PPh₃) (5). Crystal structure determinations of 3, 4, and 5 confirm that in each case there is formation of a five-membered chelate ring tethering the silyl ligand to ruthenium. In the formation of 3, 4, and 5 the Si-ligand and the two S atoms of the dimethyldithiocarbamate ligand remain meridional but the remaining triphenylphosphine ligand and the carbonyl ligand are interchanged in position leaving the donor atom of the tether trans to the CO ligand. An alternative way of considering the tethered silyl ligands in 3, 4, and 5 is as tethered, base-stabilised, silylene ligands and the structural data give some support for a contribution from this bonding model.     

Metallacyclic complexes with ortho-silylated triphenylphosphine ligands, LnOs(κ(Si,P)-SiMe2C6H4PPh2), derived from thermal reactions of the coordinatively unsaturated trimethylsilyl, methyl complex, Os(SiMe3)(Me)(CO)(PPh3)2

Reaction between Os(SiCl₃)Cl(CO)(PPh₃)₂ and five equivalents of MeLi produces a colourless intermediate, tentatively formulated as the lithium salt of the six-coordinate, dimethyl, trimethylsilyl-containing complex anion, Li[Os(SiMe₃)(Me)₂(CO)(PPh₃)₂]. Reaction of this material with ethanol releases methane and gives the red, coordinatively unsaturated methyl, trimethylsilyl-containing complex, Os(SiMe₃)(Me)(CO)(PPh₃)₂ (1). An alternative synthesis of 1 is to add one equivalent of MeLi to Os(SiMe₃)Cl(CO)(PPh₃)₂, which in turn is obtained by adding three equivalents of MeLi to Os(SiCl₃)Cl(CO)(PPh₃)₂. Treatment of 1 with p-tolyl lithium, again gives a colourless intermediate which may be Li[Os(SiMe₃)(Me)(p-tolyl)(CO)(PPh₃)₂], and reaction with ethanol gives the red complex, Os(SiMe₃)(p-tolyl)(CO)(PPh₃)₂ (3). Complexes 1 and 3 are readily carbonylated to Os(SiMe₃)(Me)(CO)₂(PPh₃)₂ (2) and Os(SiMe₃)(p-tolyl)(CO)₂(PPh₃)₂ (4), respectively. Heating Os(SiMe₃)Cl(CO)(PPh₃)₂ in molten triphenylphosphine results only in loss of the trimethylsilyl ligand and formation of the previously known complex containing an ortho-metallated triphenylphosphine ligand, Os(κ²(C,P)-C₆H₄PPh₂)Cl(CO)(PPh₃)₂. In contrast, heating the five-coordinate osmium-methyl complex, Os(SiMe₃)(Me)(CO)(PPh₃)₂ (1), in the presence of triphenylphosphine results mainly, not in tetramethylsilane elimination, but in ortho-silylation as well as ortho-metallation of different triphenylphosphine ligands giving, Os(κ²(Si,P)-SiMe₂C₆H₄PPh₂)(κ²(C,P)-C₆H₄PPh₂)(CO)(PPh₃) (5). A byproduct of this reaction is the non-silicon containing di-ortho-metallated complex, Os(κ²(C,P)-C₆H₄PPh₂)₂(CO)(PPh₃) (6). A similar reaction occurs when Os(SiMe₃)(Me)(CO)(PPh₃)₂ (1) is heated in the presence of tri(N-pyrrolyl)phosphine producing Os(κ²(Si,P)-SiMe₂C₆H₄PPh₂)(κ²(C,P)-C₆H₄PPh₂)(CO)[P(NC₄H₄)₃] (7) but a better synthesis of 7 is to treat 5 directly with tri(N-pyrrolyl)phosphine. Heating the six-coordinate complex, Os(SiMe₃)(Me)(CO)₂(PPh₃)₂ (2), gives two complexes both containing ortho-metallated triphenylphosphine, one with loss of the trimethylsilyl ligand, giving the known complex, Os(κ²(C,P)-C₆H₄PPh₂)H(CO)₂(PPh₃), and the other with retention of the trimethylsilyl ligand, giving Os(SiMe₃)(κ²(C,P)-C₆H₄PPh₂)(CO)₂(PPh₃) (8). Crystal structure determinations for 5, 6, 7 and 8 have been obtained.     

Synthesis and characterization of some novel ruthenium(II) complexes containing thiolate ligands

Reactions of the ruthenium complexes [RuH(CO)Cl(PPh₃)₃] and [RuCl₂(PPh₃)₃] with hetero-difunctional S,N-donor ligands 2-mercapto-5-methyl-1,3,5-thiadiazole (HL¹), 2-mercapto-4-methyl-5-thiazoleacetic acid (HL²), and 2-mercaptobenzothiazole (HL³) have been investigated. Neutral complexes [RuCl(CO)(PPh₃)₂(HL¹)] (1), [RuCl(CO)(PPh₃)₂(HL²)] (2), [RuCl(CO)(PPh₃)₂(HL³)] (3), [Ru(PPh₃)₂(HL¹)₂] (4), [RuCl(PPh₃)₃(HL²)] (5), and [RuCl(PPh₃)₃(HL³)] (6) imparting κ²-S,N-bonded ligands have been isolated from these reactions. Complexes 1 and 4 reacted with diphenyl-2-pyridylphosphine (PPh₂Py) to give neutral κ¹-P bonded complexes [RuCl(CO)(κ¹-P-PPh₂Py)₂(HL¹)] (7), and [Ru(κ¹-P-PPh₂Py)₂(HL¹)₂] (8). Complexes 1-8 have been characterized by analytical, spectral (IR, NMR, and electronic absorption) and electrochemical studies. Molecular structures of 1, 2, 4, and 7 have been determined crystallographically. Crystal structure determination revealed coordination of the mercapto-thiadiazole ligands (HL¹-HL³) to ruthenium as κ²-N,S-thiolates and presence of rare intermolecular S-S weak bonding interaction in complex 1.     

Syntheses and characterization of cyano-bridged homo and hetero bimetallic complexes containing η and η-cyclic hydrocarbons

The reactions of [(ind)Ru(PPh₃)₂CN] (ind = η⁵-C₉H₇) (1) and [CpRu(PPh₃)₂CN] (Cp = η⁵-C₅H₅) (2) with [(η⁶-p-cymene)Ru(bipy)Cl]Cl (bipy = 2,2′-bipyridine) (3) in the presence of AgNO₃/NH₄BF₄ in methanol, respectively, yielded dicationic cyano-bridged complexes of the type [(ind)(PPh₃)₂Ru(μ-CN)Ru(bipy)(η⁶-p-cymene)](BF₄)₂ (4) and [Cp(PPh₃)₂Ru(μ-CN)Ru(bipy)(η⁶-p-cymene)](BF₄)₂ (5). The reaction of [CpRu(PPh₃)₂CN] (2), [CpOs(PPh₃)₂CN] (6) and [CpRu(dppe)CN] (7) with the corresponding halide complexes and [(η⁶-p-cymene)RuCl₂]₂ formed the monocationic cyano-bridge complexes [Cp(PPh₃)₂Ru(μ-CN)Os(PPh₃)₂Cp](BF₄) (8), [Cp(PPh₃)₂Os(μ- CN)Ru(PPh₃)₂Cp](BF₄) (9) and [Cp(dppe)Ru(μ-CN)Os(PPh₃)₂Cp](BF₄) (10) along with the neutral complexes [Cp(PPh₃)₂Ru(μ-CN)Ru (η⁶-p-cymene)Cl₂] (11), [Cp(PPh₃)₂Os(μ-CN)Ru(η⁶-p-cymene)Cl₂] (12), and [Cp(dppe) Ru(μ-CN)Ru(η⁶-p-cymene)Cl₂] (13). These complexes were characterized by FT IR, ¹H NMR, ³¹P{¹H} NMR spectroscopy and the molecular structures of complexes 4, 8 and 11 were solved by X-ray diffraction studies.     

Monomeric and dimeric ruthenium thiooxalate complexes: Structures of CpRu(PPh3)2SCOCO2Me and CpRu(dppe)SCOCO2Et

The hydrosulfido complexes CpRu(L)(L′)SH react with one equivalent of O-alkyl oxalyl chlorides (ROCOCOCl) to form the corresponding O-alkylthiooxalate complexes CpRu(L)(L′)SCOCO₂R (L = L′ = PPh₃ (1), (2); L = PPh₃, L′ = CO (3); R = Me (a), Et (b)). The reactions of the hydrosulfido complexes with half equivalent of oxalyl chloride produce the bimetallic complexes [CpRu(L)(L′)SCO]₂ (L = L′ = PPh₃ (4), (5); L = PPh₃, L′ = CO (6)). The crystal structures of CpRu(PPh₃)₂SCOCO₂Me (1a) and CpRu(dppe)SCOCO₂Et (2b) are reported.     

Metallacyclic complexes with ortho-stannylated triphenylphosphine ligands, LnOs(κ(Sn,P)-SnMe2C6H4PPh2), derived from thermal reactions of the five-coordinate complex, Os(SnMe3)Cl(CO)(PPh3)2

Heating the five-coordinate trimethylstannyl complex, Os(SnMe₃)Cl(CO)(PPh₃)₂, in solution with triphenylphosphine induces an ortho-stannylation of one phenyl group of a triphenylphosphine ligand and an ortho-metallation of another triphenylphosphine ligand, to produce the metallacyclic complexes, Os(κ²(Sn,P)-SnMeClC₆H₄PPh₂)(κ²(C,P)-C₆H₄PPh₂)(CO)(PPh₃) (1) and Os(κ²(Sn,P)-SnMe₂C₆H₄PPh₂)(κ²(C,P)-C₆H₄PPh₂)(CO)(PPh₃) (2), suggesting the possible intermediacy of a complex with a coordinated stannylene ligand. Spectroscopic data indicate that only one diastereomer of 1 is formed and crystal structure determination of 1 reveals that this is the diastereomer with chloride directed towards the CO ligand. Complex 2 is converted to 1 through a redistribution reaction with SnMe₂Cl₂. Heating the six-coordinate trimethylstannyl complex, Os(SnMe₃)Cl(CO)₂(PPh₃)₂, in solution produces the osmium(II) methyl complex, Os(Me)(SnMe₂Cl)(CO)₂(PPh₃)₂ (3), through an exchange of methyl and chloride groups on the tin and osmium. In this rearrangement, the relative locations of the two CO ligands and the two PPh₃ ligands remains unchanged. However, when the six-coordinate trimethylstannyl complex, Os(SnMe₃)Cl(CO)₂(PPh₃)₂ is heated under CO, the same exchange reaction is observed but the mono-triphenylphosphine, tricarbonyl complex, Os(Me)(SnMe₂Cl)(CO)₃(PPh₃) (4), is produced and here the SnMe₂Cl ligand is located trans to the PPh₃ ligand. Crystal structure determinations for 1, 2, 3, and 4 have been obtained.     

Syntheses, reactions, and structures of osmium(II) distannyl complexes, LnOs-SnMe2SnR3 (R = Me, Ph), from reaction between LnOs-SnClMe2 and either LiSnMe3 or KSnPh3

Reaction between Os(SnClMe₂)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ and either LiSnMe₃ or KSnPh₃ produces the distannyl complexes, Os(SnMe₂SnMe₃)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (1) or Os(SnMe₂SnPh₃)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (3), respectively. Similarly, reaction between Os(SnClMe₂)Cl(CO)₂(PPh₃)₂ (6) and KSnPh₃ produces the distannyl complex, Os(SnMe₂SnPh₃)Cl(CO)₂(PPh₃)₂ (7). In the ¹¹⁹Sn NMR spectra of these stable osmium(II) distannyl complexes both the α-Sn and β-Sn atoms show well-resolved ¹¹⁹Sn-¹¹⁹Sn and ¹¹⁹Sn-¹¹⁷Sn coupling. Each of these three distannyl complexes can be selectively functionalised at the α-Sn atom by reaction with SnCl₂Me₂ giving Os(SnClMeSnMe₃)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (2), Os(SnClMeSnPh₃)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (4), and Os(SnClMeSnPh₃)Cl(CO)₂(PPh₃)₂ (8), respectively. Treatment of compounds 3 or 7 with iodine also cleaves one α-methyl group, selectively, to give Os(SnIMeSnPh₃)(κ²-S₂CNMe₂)(CO)(PPh₃)₂ (5), or Os(SnIMeSnPh₃)Cl(CO)₂(PPh₃)₂ (9). Crystal structures for complexes 3 and 7 have been determined.     

Nucleophilic substitution reactions at the Si-Cl bonds of the dichloro(methyl)silyl ligand in five- and six-coordinate complexes of ruthenium(II) and osmium(II)

Treatment of either RuHCl(CO)(PPh₃)₃ or MPhCl(CO)(PPh₃)₂ with HSiMeCl₂ produces the five-coordinate dichloro(methyl)silyl complexes, M(SiMeCl₂)Cl(CO)(PPh₃)₂ (1a, M = Ru; 1b, M = Os). 1a and 1b react readily with hydroxide ions and with ethanol to give M(SiMe[OH]₂)Cl(CO)(PPh₃)₂ (2a, M = Ru; 2b, M = Os) and M(SiMe[OEt]₂)Cl(CO)(PPh₃)₂ (3a, M = Ru; 3b, M = Os), respectively. 3b adds CO to form the six-coordinate complex, Os(SiMe[OEt]₂)Cl(CO)₂(PPh₃)₂ (4b) and crystal structure determinations of 3b and 4b reveal very different Os-Si distances in the five-coordinate complex (2.3196(11) Å) and in the six-coordinate complex (2.4901(8) Å). Reaction between 1a and 1b and 8-aminoquinoline results in displacement of a triphenylphosphine ligand and formation of the six-coordinate chelate complexes M(SiMeCl₂)Cl(CO)(PPh₃)(κ²(N,N)-NC₉H₆NH₂-8) (5a, M = Ru; 5b, M = Os), respectively. Crystal structure determination of 5a reveals that the amino function of the chelating 8-aminoquinoline ligand is located adjacent to the reactive Si-Cl bonds of the dichloro(methyl)silyl ligand but no reaction between these functions is observed. However, 5a and 5b react readily with ethanol to give ultimately M(SiMe[OEt]₂)Cl(CO)(PPh₃)(κ²(N,N-NC₉H₆NH₂-8) (6a, M = Ru; 6b, M = Os). In the case of ruthenium only, the intermediate ethanolysis product Ru(SiMeCl[OEt])Cl(CO)(PPh₃)(κ²(N,N-NC₉H₆NH₂-8) (6c) was also isolated. The crystal structure of 6c was determined. Reaction between 1b and excess 2-aminopyridine results in condensation between the Si-Cl bonds and the N-H bonds with formation of a novel tridentate “NSiN” ligand in the complex Os(κ³(Si,N,N)-SiMe[NH(2-C₅H₄N)]₂)Cl(CO)(PPh₃) (7b). Crystal structure determination of 7b shows that the “NSiN” ligand coordinates to osmium with a “facial” arrangement and with chloride trans to the silyl ligand.     

Trifluoroacetylacetonate rhodium(III) methyl complexes, cis-[Rh(TFA)(PPh3)2(CH3)(L)][BPh4] and cis-[Rh(TFA)(PPh3)2(CH3)(I)] (L = CH3CN, NH3, pyridine), in comparison with their acetylacetonate analogs

The oxidative addition of CH₃I to planar rhodium(I) complex [Rh(TFA)(PPh₃)₂] in acetonitrile (TFA is trifluoroacetylacetonate) leads to the formation of cationic, cis-[Rh(TFA)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄] (1), or neutral, cis-[Rh(TFA)(PPh₃)₂(CH₃)(I)] (4), rhodium(III) methyl complexes depending on the reaction conditions. 1 reacts readily with NH₃ and pyridine to form cationic complexes, cis-[Rh(TFA)(PPh₃)₂(CH₃)(NH₃)][BPh₄] (2) and cis-[Rh(TFA)(PPh₃)₂(CH₃)(Py)][BPh₄] (3), respectively. Acetylacetonate methyl complex of rhodium(III), cis-[Rh(Acac)(PPh₃)₂(CH₃)(I)] (5), was obtained by the action of NaI on cis-[Rh(Acac)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄] in acetone at −15 °C. Complexes 1-5 were characterized by elemental analysis, ³¹P{¹H}, ¹H and ¹⁹F NMR. For complexes 2, 3, 4 conductivity data in acetone solutions are reported. The crystal structures of 2 and 3 were determined. NMR parameters of 1-5 and related complexes are discussed from the viewpoint of their isomerism.     

The structurally characterised silyl complexes, Os(κ-S2CNMe2)(SiMeCl2)(CO)(PPh3)2 and Os(κ-S2CNMe2)(SiCl3)(CO)(PPh3)2, which have remarkably unreactive Si-Cl bonds

Treatment of Os(κ²-S₂CNMe₂)H(CO)(PPh₃)₂ with HSiMeCl₂ or HSiCl₃ gives in high yield Os(κ²-S₂CNMe₂)(SiMeCl₂)(CO)(PPh₃)₂ (1) or Os(κ²-S₂CNMe₂)(SiCl₃)(CO)(PPh₃)₂ (2), respectively. The crystal structures of both compounds have been determined and the Os-Si distances are 2.3672(10) Å for 1 and 2.3449(12) Å for 2. In solution, and under forcing conditions, both compounds are extraordinarily unreactive towards hydroxide ions.     

Synthesis, and characterization of ruthenium(II) polypyridyl complexes containing α-amino acids and its DNA binding behavior

Reactivity of the ruthenium complexes [Ru(κ³-tptz)(PPh₃)Cl₂] (1) and [Ru(κ³-tpy)(PPh₃)Cl₂] (2) [tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine; tpy = 2,2′:6′,2″-terpyridine] with several α-amino acids [glycine (gly); leucine (leu); isoleucine (isoleu); valine (val); tyrosine (tyr); proline (pro) and phenylalanine (phe)] have been investigated. Cationic complexes with the general formulations [Ru(κ³-L)(κ²-L″)(PPh₃)]⁺ (L = tptz or tpy; L″ = gly, leu, isoleu, val, tyr, pro, and phe] have been isolated as tetrafluoroborate salts. The resulting complexes have been thoroughly characterized by analytical, spectral and electrochemical studies. Molecular structures of the representative complexes [Ru(κ³-tptz)(val)(PPh₃)]BF₄ (6)_, [Ru(κ³-tpy)(leu)(PPh₃)]BF₄ (10) and [Ru(κ³-tpy)(tyr)(PPh₃)]BF₄ (13) have been determined crystallographically. The complexes [Ru(κ³-tptz)(leu)(PPh₃)]BF₄ (4), [Ru(κ³-tptz)(val)(PPh₃)]BF₄ (6), [Ru(κ³-tpy)(leu)(PPh₃)]BF₄ (10) [Ru(κ³-tpy)(tyr)(PPh₃)] BF₄·3H₂O (13) exhibited DNA binding behavior and acted as mild Topo II inhibitors (10-40%). The complexes also inhibited heme polymerase activity of the malarial parasite Plasmodium yoelii lysate.     

Bio-catalysts and catalysts based on ruthenium(II) polypyridyl complexes imparting diphenyl-(2-pyridyl)-phosphine as a co-ligand

Reactions of the ruthenium complexes [Ru(κ³-tpy)(PPh₃)Cl₂], [Ru(κ³-tptz)(PPh₃)Cl₂] and [Ru(κ³-tpy)Cl₃] [tpy = 2,2′:6′,2′′-terpyridine; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine] with diphenyl-(2-pyridyl)-phosphine (PPh₂Py) have been investigated. The complexes [Ru(κ³-tpy)(PPh₃)Cl₂] and [Ru(κ³-tptz)(PPh₃)Cl₂] reacted with PPh₂Py to afford [Ru(κ³-tpy)(κ¹-P-PPh₂Py)₂Cl]⁺ (1) and [Ru(κ³-tptz)(κ¹-P-PPh₂Py)₂Cl]⁺ (2), which were isolated as their tetrafluoroborate salts. Under analogous conditions, [Ru(κ³-tpy)Cl₃] gave a neutral complex [Ru(κ³-tpy)(κ¹-PPh₂Py)Cl₂] (3). Upon treatment with an excess of NH₄PF₆ in methanol, 1 and 2 gave [Ru(κ³-tpy)(κ¹-P-PPh₂Py)(κ²-P,N-PPh₂Py)](PF₆)₂ (4) and [Ru(κ³-tptz)(κ¹-P-PPh₂Py)(κ²-P,N-PPh₂Py)](PF₆)₂ (5) containing both monodentate and chelated PPh₂Py. Further, 4 and 5 reacted with an excess of NaCN and CH₃CN to afford [Ru(κ³-tpy)(κ¹-P-PPh₂Py)₂(CN)](PF₆) (6), [Ru(κ³-tpy)(κ¹-P-PPh₂Py)₂(NCCH₃)](PF₆)₂ (7), [Ru(κ³-tptz)(κ¹-P-PPh₂Py)₂(CN)]PF₆ (8) and [Ru(κ³-tptz)(κ¹-P-PPh₂Py)₂(NCCH₃)](PF₆)₂ (9) supporting hemi labile nature of the coordinated PPh₂Py. The complexes have been characterized by elemental analyses, spectral (IR, NMR, electronic absorption, FAB-MS), electrochemical studies and structures of 1, 2 and 3 determined by X-ray single crystal analyses. At higher concentration level (40 μM) the complexes under investigation exhibit inhibitory activity against DNA-Topo II of the filarial parasite S. cervi and 3 catalyses rearrangement of aldoximes to amide under aerobic conditions.     

Hydrolytic disproportionation of coordinated white phosphorus in [CpRu(dppe)(η-P4)]PF6 [dppe = 1,2-bis(diphenylphosphino)ethane]

The reaction of [CpRu(dppe)Cl] (1), dppe = 1,2-bis(diphenylphosphino)ethane, with one equivalent of P₄ in the presence of TlPF₆ affords the stable complex [CpRu(dppe)(η¹-P₄)]PF₆ (2) which contains the tetrahedral P₄ molecule η¹-bound to the metal. The tetraphosphorus ligand readily reacts with water upon mixing acetone or THF solutions of the complex with excess water. The complexes [CpRu(dppe)(PH₃)]PF₆ (5) and [CpRu(dppe){P(OH)₃}]PF₆ (6), identified among the hydrolysis products, contain the PH₃ molecule and, respectively, the unstable P(OH)₃ tautomer of the phosphorous acid bound to the CpRu(dppe) fragment. In CH₂Cl₂ the coordinated P(OH)₃ molecule in 6 easily yields the compound [CpRu(dppe){PF(OH)₂}]PF₂O₂ (8), via hydrolysis of the hexafluorophosphate anion and F/OH substitution in the coordinated P(OH)₃ molecule. All the compounds have been characterized by elemental analyses and NMR measurements. The crystal structures of 2 and 8 have been determined by X-ray diffraction methods.     

Ruthenium(II), copper(I) and silver(I) complexes of large bite bisphosphinite, bis(2-diphenylphosphinoxynaphthalen-1-yl)methane: Application of Ru(II) complexes towards the hydrogenation of styrene and phenylacetylene

Ruthenium(II), copper(I) and silver(I) complexes of large bite bisphosphinite Ph₂P{(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)}PPh₂ (1) are described. Reactions of bisphosphinite 1 with [Ru(η⁶-p-cymene)(μ-Cl)Cl]₂ and RuCl₂(PPh₃)₃ afford mono- and bis-chelate complexes [RuCl(η⁶-p-cymene){η²-Ph₂P{(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)}PPh₂-κP,κP}]Cl (2) and trans-[RuCl₂{η²-Ph₂P{(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)}PPh₂-κP,κP}₂] (3), respectively. Treatment of 1 with CuX (X = Cl, Br and I) furnish 10-membered chelate complexes of the type [Cu(X){η²-Ph₂P(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)PPh₂-κP,κP}] (4, X = Cl; 5, X = Br; 6, X = I), whereas [Cu(MeCN)₄]PF₆ affords a bis-chelated cationic complex [Cu{η²-Ph₂P(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)PPh₂-κP,κP}₂][PF₆] (7). Reaction between 1 and AgOTf produce both mono- and bis-chelated complexes [Ag{η²-Ph₂P(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)PPh₂-κP,κP}(SO₃CF₃)] (8) and [Ag{η²-Ph₂P(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)PPh₂-κP,κP}₂][SO₃CF₃] (9), respectively; whereas the similar reaction of 1 with[Ag(OTf)PPh₃] affords chelate complex of the type [Ag{η²-Ph₂P(-OC₁₀H₆)(μ-CH₂)(C₁₀H₆O-)PPh₂-κP,κP}(PPh₃)(SO₃CF₃)] (10). All the complexes were characterized by ¹H NMR, ³¹P NMR, elemental analysis and mass spectrometry, including low-temperature NMR studies in the case of silver complexes. The molecular structures of 4 and 6 are determined by X-ray diffraction studies. Ruthenium complexes 2 and 3 promote catalytic hydrogenation of styrene and phenylacetylene with good turnover numbers.     

The influence of substituents (R) at the C carbon on bonding properties of thiosemicarbazones {RC(H)N-NH–C(S)–NH2} in palladium(II) complexes

Reactions of the trans-PdCl₂(PPh₃)₂ precursor with furan-2-carbaldehyde thiosemicarbazone (Hftsc) and thiophene-2-carbaldehyde thiosemicarbazone (Httsc), in 1:1 molar ratios in the presence of Et₃N base, removed one Cl and one PPh₃ group from the Pd^II center, and yielded the complexes [Pd(η²-N³,S-ftsc)(PPh₃)Cl] (1) and [Pd(η²-N³,S-ttsc)(PPh₃)Cl] (2), respectively. However, when a 1:2 molar ratio (M:L) was used, both Cl and PPh₃ ligands were removed, yielding the complexes trans-[Pd(η²-N³,S-ftsc)₂] (3) and trans-[Pd(η²-N³,S-ttsc)₂] (4). Complexes 1–4 have been characterized with the help of analytical data, spectroscopic techniques (IR, ¹H and ³¹P NMR) and single crystal X-ray crystallography. The thiosemicarbazone ligands behave as uninegative N³,S-chelating ligands in complexes 1–4. In contrast, pyrrole-2-carbaldehyde thiosemicarbazone (H₂ptsc) and salicylaldehyde thiosemicarbazone (H₂stsc) invariably formed the complexes [Pd(η³-N⁴,N³,S-ptsc)(PPh₃)] (5) and [Pd(η³–O, N³,S-stsc)(PPh₃)] (6), respectively, and the ligands acted as binegative tridentate donors (N⁴, N³, S, 5; O, N³, S, 6).     

Cationic methyl complexes of rhodium(III): synthesis, structure, and some reactions

Cationic methyl complex of rhodium(III), trans-[Rh(Acac)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄] (1) is prepared by interaction of trans-[Rh(Acac)(PPh₃)₂(CH₃)I] with AgBPh₄ in acetonitrile. Cationic methyl complexes of rhodium(III), cis-[Rh(Acac)(PPh₃)₂ (CH₃)(CH₃CN)][BPh₄] (2) and cis-[Rh(BA)(PPh₃)₂(CH₃)(CH₃CN)][BPh₄] (3) (Acac, BA are acetylacetonate and benzoylacetonate, respectively), are obtained by CH₃I oxidative addition to rhodium(I) complexes [Rh(Acac)(PPh₃)₂] and [Rh(BA)(PPh₃)₂] in acetonitrile in the presence of NaBPh₄. Complexes 2 and 3 react readily with NH₃ at room temperature to form cis-[Rh(Acac)(PPh₃)₂(CH₃)(NH₃)][BPh₄] (4) and cis-[Rh(BA)(PPh₃)₂(CH₃)(NH₃)][BPh₄] (5), respectively. Complexes 1-5 were characterized by elemental analysis, ¹H and ³¹P{¹H} NMR spectra. Complexes 1, 2, 3 and 4 were characterized by X-ray diffraction analysis. Complexes 2 and 3 in solutions (CH₂Cl₂, CHCl₃) are presented as mixtures of cis-(PPh₃)₂ isomers involved into a fluxional process. Complex 2 on heating in acetonitrile is converted into trans-isomer 1. In parallel with that isomerization, reductive elimination of methyl group with formation of [CH₃PPh₃][BPh₄] takes place. Replacement of CH₃CN in complexes 1 and 2 by anion I⁻ yields in both cases the neutral complex trans-[Rh(Acac)(PPh₃)₂(CH₃)I]. Strong trans influence of CH₃ ligand manifests itself in the elongation (in solid) and labilization (in solution) of rhodium-acetonitrile nitrogen bond.     

Structures, preparation and catalytic activity of ruthenium cyclopentadienyl complexes based on pyridyl-phosphine ligand

Ruthenium complexes [(η⁵-C₅H₅)Ru(κ¹-P-PPh₂Py)(PPh₃)Cl] (1) and [(η⁵-C₅H₅)Ru(κ²-P-N-PPh₂Py)(PPh₃)]⁺ (1a) containing diphenyl-2-pyridylphosphine (PPh₂Py) are reported. Coordinated PPh₂Py in the complex [(η⁵-C₅H₅)Ru(κ¹-P-PPh₂Py)(PPh₃)Cl] (1) exhibits monodentate behavior. In presence of NH₄PF₆ in methanol at room temperature it afforded chelated complex [(η⁵-C₅H₅)Ru(κ²-P,N-PPh₂Py)(PPh₃)]⁺ (1a). Further, 1 reacted with various species viz., CH₃CN, NaCN, NH₄SCN and NaN₃ to afford cationic and neutral complexes [(η⁵-C₅H₅)Ru(κ¹-P-PPh₂Py)(PPh₃)L]⁺ and [(η⁵-C₅H₅)Ru(κ¹-P-PPh₂Py)(PPh₃)L] [L = CH₃CN (1b); CN⁻ (1c); N₃⁻ (1d) and SCN⁻ (1e)] and it’s reaction with N,N-donor chelating ligands dimethylglyoxime (H₂dmg) and 1,2-phenylenediamine (pda) gave cationic complexes [(η⁵-C₅H₅)Ru(κ¹-P-PPh₂Py)(κ²-N-N)]PF₆ [κ²-N-N = dmg (1f) and pda (1g)]. The complexes 1-1g have been characterized by physicochemical techniques and crystal structures of 1, 1a, 1c, 1e and 1f have been determined by single crystal X-ray analyses. Catalytic potential of the complex 1 has been evaluated in water under aerobic conditions. It was observed that the complex 1 selectively catalyzes reduction of aldehyde into alcohol.     

Alkyne activation by half-sandwich ruthenium(II) complexes bearing the water-soluble phosphane 1,3,5-triaza-7-phosphaadamantane (PTA)

Complex [RuCl{κ³(N,N,N)-Tp}(PPh₃)(PTA)] (κ³(N,N,N)-Tp = hydridotris(pyrazolyl)borate) containing the water-soluble phosphane 1,3,5-triaza-7-phosphatricyclo[3.3.1.1^3,7]decane (PTA) reacts with terminal alkynes producing to the corresponding neutral alkynyl complexes [Ru(CCR){κ³(N,N,N)-Tp}(PPh₃)(PTA)] (R = Ph (1a), ⁿBu (1b), 1-cyclopentenyl (1c), p-methoxyphenyl (1d), 6-methoxynaft-2-yl (1e)). When halide is extracted from complex [RuCl{κ³(N,N,N)-Tp}(PPh₃)(PTA)] followed by treatment with propargyl alcohols, the corresponding allenylidene complexes [Ru{κ³(N,N,N)-Tp}(PPh₃)(PTA)(CCCPh₂)][X] (X = PF₆ (2a), CF₃SO₃ (2b)) and [Ru{κ³(N,N,N)-Tp}(PPh₃)(PTA)(CCCC₁₂H₈)][PF₆] (3) result. Electrophilic attack on the complexes thus obtained leads chemoselectively to the alkynyl complexes [Ru(CCR){κ³(N,N,N)-Tp}(PPh₃)(1-CH₃-PTA)][CF₃SO₃] (R = Ph (4a), ⁿBu (4b), and 1-cyclopentenyl (4c)) and to the dicationic allenylidene complexes [Ru{κ³(N,N,N)-Tp}(PPh₃)(1-H-PTA)(CCCC₁₂H₈)][PF₆]₂ (5) and [Ru{κ³(N,N,N)-Tp}(PPh₃)(1-CH₃-PTA)(CCCPh₂)][CF₃SO₃]₂ (6).