Chalcogen-capped ruthenium carbonyl clusters derived from diphosphazane mono- and dichalcogenides of the type X2P(E)N(R)PX2 and X2P(E)N(R)P(E)X2 (E = S or Se)

Reactions of Ru₃(CO)₁₂ with diphosphazane monoselenides Ph₂PN(R)P(Se)Ph₂ [R = (S)-∗CHMePh (L⁴), R = CHMe₂ (L⁵)] yield mainly the selenium bicapped tetraruthenium clusters [Ru₄(μ₄-Se)₂(μ-CO)(CO)₈{μ-P,P-Ph₂PN(R)PPh₂}] (1, 3). The selenium monocapped triruthenium cluster [Ru₃(μ₃-Se)(μ_sb-CO)(CO)₇{κ²-P,P-Ph₂PN((S)-∗CHMePh)PPh₂}] (2) is obtained only in the case of L⁴. An analogous reaction of the diphosphazane monosulfide (PhO)₂PN(Me)P(S)(OPh)₂ (L⁶) that bears a strong π-acceptor phosphorus shows a different reactivity pattern to yield the triruthenium clusters, [Ru₃(μ₃-S)(μ₃-CO)(CO)₇{μ-P,P-(PhO)₂PN(Me)P(OPh)₂}] (9) (single sulfur transfer product) and [Ru₃(μ₃-S)₂(CO)₅{κ²-P,P-(PhO)₂PN(Me)P(OPh)₂}{μ-P,P-(PhO)₂PN(Me)P(OPh)₂}] (10) (double sulfur transfer product). The reactions of diphosphazane dichalcogenides with Ru₃(CO)₁₂ yield the chalcogen bicapped tetraruthenium clusters [Ru₄(μ₄-E)₂(μ-CO)(CO)₈{μ-P,P-Ph₂PN(R)PPh₂}] [R = (S)-∗CHMePh, E = S (6); R = CHMe₂, E = S (7); R = CHMe₂, E = Se (3)]. Such a tetraruthenium cluster [Ru₄(μ₄-S)₂(μ- CO)(CO)₈{μ-P,P-(PhO)₂PN(Me)P(OPh)₂}] (11) is also obtained in small quantities during crystallization of cluster 9. The dynamic behavior of cluster 10 in solution is probed by NMR studies. The structural data for clusters 7, 9, 10 and 11 are compared and discussed.     

Steric and electronic effects in stabilizing allyl-palladium complexes of “P-N-P” ligands, X2PN(Me)PX2 (X = OC6H5 or OC6H3Me2-2,6)

The chemistry of η³-allyl palladium complexes of the diphosphazane ligands, X₂PN(Me)PX₂ [X = OC₆H₅ (1) or OC₆H₃Me₂-2,6 (2)] has been investigated.The reactions of the phenoxy derivative, (PhO)₂PN(Me)P(OPh)₂ with [Pd(η³-1,3-R′,R″-C₃H₃)(μ-Cl)]₂ (R′ = R″ = H or Me; R′ = H, R″ = Me) give exclusively the palladium dimer, [Pd₂{μ-(PhO)₂PN(Me)P(OPh)₂}₂Cl₂] (3); however, the analogous reaction with [Pd(η³-1,3-R′,R″-C₃H₃)(μ-Cl)]₂ (R′ = R″ = Ph) gives the palladium dimer and the allyl palladium complex [Pd(η³-1,3-R′,R″-C₃H₃)(1)](PF₆) (R′ = R″ = Ph) (4). On the other hand, the 2,6-dimethylphenoxy substituted derivative 2 reacts with (allyl) palladium chloro dimers to give stable allyl palladium complexes, [Pd(η³-1,3-R′,R″-C₃H₃)(2)](PF₆) [R′ = R″ = H (5), Me (7) or Ph (8); R′ = H, R″ = Me (6)].Detailed NMR studies reveal that the complexes 6 and 7 exist as a mixture of isomers in solution; the relatively less favourable isomer, anti-[Pd(η³-1-Me-C₃H₄)(2)](PF₆) (6b) and syn/anti-[Pd(η³-1,3-Me₂-C₃H₃)(2)](PF₆) (7b) are present to the extent of 25% and 40%, respectively. This result can be explained on the basis of the steric congestion around the donor phosphorus atoms in 2. The structures of four complexes (4, 5, 7a and 8) have been determined by X-ray crystallography; only one isomer is observed in the solid state in each case.     

Orthopalladation of phosphorus ylides in endo position with bidentate ligands

The ortho-metallated complexes [Pd₂{κ²(C,C)-C₆H₄(PPh₂CHC(O)C₆H₅R}₂(μ-Cl)₂] (R = Ph (1a), NO₂ (1b), Br (1c)) were prepared by refluxing equimolar mixtures of Ph₃PCHC(O)C₆H₅R, (R = Ph, NO₂, Br) and Pd(OAc)₂ in MeOH, followed by an excess of NaCl. The dinuclear complexes (1a-1c) react with silver trifluoromethylsulfonate and bidentate ligands [L = bipy (2,2′-bipyridine), phen (phenanthroline), dppe (bis(diphenylphosphino)ethane), dppp (bis(diphenylphosphino)propane)] giving the mononuclear stabilized orthopalladated complexes in endo position [Pd{κ²(C,C)-C₆H₄(PPh₂CHC(O)R}L](OTf) [R = Ph, L = phen (2a), bipy (3a), dppe (4a), dppp (5a); R = NO₂, L = phen (2b), bipy (3b), dppe (4b), dppp (5b); R = Br, L = phen (2c), bipy (3c), dppe (4c), dppp (5c); OTf = trifluoromethylsulfonate anion]. Orthometalation and ylidic C-coordination are demonstrated by an X-ray diffraction study of 2c and 3c. In the structures, the palladium atom shows a slightly distorted square-planar coordination geometry.     

Reactivity of the triruthenium ortho-metalated cluster [Ru3(CO)9{μ3-η,κ,κ-PhP(C6H4)CH2PPh}] with tri(2-thienyl)phosphine and tri(2-furyl)phosphine: Formation of 1,3-diphenyl-2,3-dihydro-1H-1,3-benzodiphosphine complexes via phosphorus-carbon bond formation

Reaction of [Ru₃(CO)₉{μ₃-η¹,κ¹,κ²-PhP(C₆H₄)CH₂PPh}] (1) with tri(2-thienyl)phosphine (PTh₃) in refluxing THF afforded [Ru₃(CO)₉(PTh₃)(μ-dpbm)] (3) {dpbm = PhP(C₆H₄)(CH₂)PPh} and [Ru₃(CO)₆(μ-CO)₂{μ-κ¹,η¹-PTh₂(C₄H₂S)}{μ₃-κ¹,κ²-Ph₂PCH₂PPh}] (5) in 18% and 12% yields, respectively, while a similar reaction with tri(2-furyl)phosphine (PFu₃) gave [Ru₃(CO)₉(PFu₃)(μ-dpbm)] (4) and [Ru₃(CO)₇(μ-η¹,η²-C₄H₃O)(μ-PFu₂){μ₃-η¹,κ¹,κ²-PhP(C₆H₄)CH₂PPh}] (6) in 24% and 27% yields, respectively. Compounds 2 and 4 are phosphine adducts of 1 in which the diphosphine ligand is transformed into 1,3-diphenyl-2,3-dihydro-1H-1,3-benzodiphosphine (dpbm) via phosphorus-carbon bond formation. Cluster 5 results from metalation of a thienyl ring, the cleaved proton being transferred to the diphosphine. Carbon-phosphorus bond cleavage of a PFu₃ ligand is observed in 6 to afford a phosphido-bridge and a furyl fragment, the latter bridging in a σ,π-vinyl fashion. The molecular structures of 3, 5 and 6 have been determined by X-ray diffraction studies.     

New diruthenium vinyliminium complexes from the insertion of alkynes into bridging aminocarbynes

Primary alkynes R′CCH [R′ = Me₃Si, Tol, CH₂OH, CO₂Me, (CH₂)₄CCH, Me] insert into the metal-carbon bond of diruthenium μ-aminocarbynes [Ru₂{μ-CN(Me)(R)}(μ-CO)(CO)(MeCN)(Cp)₂][SO₃CF₃] [R = 2,6-Me₂C₆H₃ (Xyl), 1a; CH₂Ph (Bz), 1b; Me, 1c] to give the vinyliminium complexes [Ru₂{μ-η¹:η³-C(R′)CHCN(Me)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] [R = Xyl, R′ = Me₃Si, 2a; R = Bz, R′ = Me₃Si, 2b; R = Me, R′ = Me₃Si, 2c; R = Xyl, R′ = Tol, 3a; R = Bz, R′ = Tol, 3b; R = Bz, R′ = CH₂OH, 4; R = Bz, R′ = CO₂Me, 5a; R = Me, R′ = CO₂Me, 5b; R = Xyl, R′ = (CH₂)₄CCH, 6; R = Xyl, R′ = Me, 7a; R = Bz, R′ = Me, 7b; R = Me, R′ = Me, 7c]. The related compound [Ru₂{μ-η¹:η³-C[C(Me)CH₂]CHCN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂][SO₃CF₃], (9) is better prepared by reacting [Ru₂{μ-CN(Me)(Xyl)}(μ-CO)(CO)(Cl)(Cp)₂] (8) with AgSO₃CF₃ in the presence of HCCC(Me)CH₂ in CH₂Cl₂ at low temperature.In a similar way, also secondary alkynes can be inserted to give the new complexes [Ru₂{μ-η¹:η³-C(R′)C(R′)CN(Me)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = Bz, R′ = CO₂Me, 11; R = Xyl, R′ = Et, 12a; R = Bz, R′ = Et, 12b; R = Xyl, R′ = Me, 13). The reactions of 2-7, 9, 11-13 with hydrides (i.e., NaBH₄, NaH) have been also studied, affording μ-vinylalkylidene complexes [Ru₂{μ-η¹:η³-C(R′)C(R″)C(H)N(Me)(R)}(μ-CO)(CO)(Cp)₂] (R = Bz, R′ = Me₃Si, R″ = H, 14a; R = Me, R′ = Me₃Si, R″ = H, 14b; R = Bz, R′ = Tol, R″ = H, 15; R = Bz, R′ = R″ = Et, 16), bis-alkylidene complexes [Ru₂{μ-η¹:η²-C(R′)C(H)(R″)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂] (R′ = Me₃Si, R″ = H, 17; R′ = R″ = Et, 18), acetylide compounds [Ru₂{μ-CN(Me)(R)}(μ-CO)(CO)(CCR′)(Cp)₂] (R = Xyl, R′ = Tol, 19; R = Bz, R′ = Me₃Si, 20; R = Xyl, R′ = Me, 21) or the tetranuclear species [Ru₂{μ-η¹:η²-C(Me)CCN(Me)(Bz)}(μ-CO)(CO)(Cp)₂]₂ (23) depending on the properties of the hydride and the substituents on the complex. Chromatography of 21 on alumina results in its conversion into [Ru₂{μ-η³:η¹-C[N(Me)(Xyl)]C(H)CCH₂}(μ-CO)(CO)(Cp)₂] (22). The crystal structures of 2a[CF₃SO₃] · 0.5CH₂Cl₂, 12a[CF₃SO₃] and 22 have been determined by X-ray diffraction studies.     

Olefin-aminocarbyne coupling in diiron complexes: Synthesis of new bridging aminoallylidene complexes

The bridging aminocarbyne complexes [Fe₂{μ-CN(Me)(R)}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃] (R = Me, 1a; Xyl, 1b; 4-C₆H₄OMe, 1c; Xyl = 2,6-Me₂C₆ H₃) react with acrylonitrile or methyl acrylate, in the presence of Me₃NO and NaH, to give the corresponding μ-allylidene complexes [Fe₂{μ-η¹:η³- C_α(N(Me)(R))C_β(H)C_γ(H)(R′)}(μ-CO)(CO)(Cp)₂] (R = Me, R′ = CN, 3a; R = Xyl, R′ = CN, 3b; R = 4-C₆H₄OMe, R′ = CN, 3c; R = Me, R′ = CO₂Me, 3d; R = 4-C₆H₄OMe, R′ = CO₂Me, 3e). Likewise, 1a reacts with styrene or diethyl maleate, under the same reaction conditions, affording the complexes [Fe₂{μ-η¹:η³-C_α(NMe₂)C_β(R′)C_γ(H)(R″)}(μ-CO)(CO)(Cp)₂] (R′ = H, R″ = C₆H₅, 3f; R′ = R″ = CO₂Et, 3g). The corresponding reactions of [Ru₂{μ-CN(Me)(CH₂Ph)}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃] (1d) with acrylonitrile or methyl acrylate afford the complexes [Ru₂{μ-η¹:η³-C_α(N(Me)(CH₂Ph))C_β(H)C_γ(H)(R′)}(μ-CO)(CO)(Cp)₂] (R′ = CN, 3h; CO₂Me, 3i), respectively.The coupling reaction of olefin with the carbyne carbon is regio- and stereospecific, leading to the formation of only one isomer. C-C bond formation occurs selectively between the less substituted alkene carbon and the aminocarbyne, and the C_β-H, C_γ-H hydrogen atoms are mutually trans.The reactions with acrylonitrile, leading to 3a-c and 3h involve, as intermediate species, the nitrile complexes [M₂{μ-CN(Me)(R)}(μ-CO)(CO)(NC-CHCH₂)(Cp)₂][SO₃CF₃] (M = Fe, R = Me, 4a; M = Fe, R = Xyl, 4b; M = Fe, R = 4-C₆H₄OMe, 4c; M = Ru, R = CH₂C₆H₅, 4d).Compounds 3a, 3d and 3f undergo methylation (by CH₃SO₃CF₃) and protonation (by HSO₃CF₃) at the nitrogen atom, leading to the formation of the cationic complexes [Fe₂{μ-η¹:η³-C_α(N(Me)₃)C_β(H)C_γ(H)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = CN, 5a; R = CO₂Me, 5b; R = C₆H₅, 5c) and [Fe₂{μ-η¹:η³-C_α(N(H)(Me)₂)C_β(H)C_γ(H)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = CN, 6a; R = CO₂Me, 6b; R = C₆H₅, 6c), respectively.Complex 3a, adds the fragment [Fe(CO)₂(THF)(Cp)]⁺, through the nitrile functionality of the bridging ligand, leading to the formation of the complex [Fe₂{μ-η¹:η³-C_α(NMe₂)C_β(H)C_γ(H)(CNFe(CO)₂Cp)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (9).In an analogous reaction, 3a and [Fe₂{μ-CN(Me)(R)}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃], in the presence of Me₃NO, are assembled to give the tetrameric species [Fe₂{μ-η¹:η³-C_α(NMe₂)C_β(H)C_γ(H)(CN[Fe₂{μ- CN(Me)(R)}(μ-CO)(CO)(Cp)₂])}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = Me, 10a; R = Xyl, 10b; R = 4-C₆H₄OMe, 10c).The molecular structures of 3a and 3b have been determined by X-ray diffraction studies.     

Trimethylstannyl (diphenylphosphino)acetate: a source of (diphenylphosphino)acetate ligand in the synthesis of coordination compounds

Trimethylstannyl (diphenylphosphino)acetate (1), which is readily accessible from potassium (diphenylphosphino)acetate and trimethylstannyl chloride, may serve as the source of (diphenylphosphino)acetate anion in the preparation of coordination compounds. Thus, the reactions between [M(cod)Cl₂] (M = Pd and Pt; cod = η²:η²-cycloocta-1,5-diene) and two equivalents of 1 give [M(Ph₂PCH₂CO₂-κ²O,P)₂] (2 and 3), while the reaction of [{Pd(μ-Cl)Cl(PFur₃)}₂] (4; Fur = 2-furyl) with one equivalent of 1 yields [SP-4-3]-[PdCl(Ph₂PCH₂CO₂-κ²O,P)(PFur₃)] (5). The reactions of 1 with the dimers [{Rh(η⁵-C₅Me₅)Cl(μ-Cl)}₂] and [{Ru(η⁶-1,4-MeC₆H₄(CHMe₂))Cl(μ-Cl)}₂] (at 1-to-metal ratio 1:1) produce O,P-chelated complexes as well, albeit as stable adducts with the liberated Me₃SnCl: [RhCl(η⁵-C₅Me₅)(Ph₂PCH₂CO₂-κ²O,P)] · Me₃SnCl (6) and[RuCl(η⁶-1,4-MeC₆H₄(CHMe₂))(Ph₂PCH₂CO₂-κ²O,P)] · Me₃SnCl (8). The related complexes with P-monodentate (diphenylphosphino)acetic acid, [RhCl₂(η⁵-C₅Me₅)(Ph₂PCH₂CO₂H-κ,P)] (7) and [RuCl₂(η⁶-1,4-MeC₆H₄(CHMe₂))(Ph₂PCH₂CO₂H-κP)] (9), were obtained by bridge splitting in the dimers with the phosphinocarboxylic ligand. All new compounds were characterized by spectral methods and combustion analyses, and the structures of 2 · 3CH₂Cl₂, 3, 4, 5, 6 and 8 were determined by X-ray crystallography.     

Reactions of Mo(II)-tetraphosphine complex [MoCl2{meso-o-C6H4(PPhCH2CH2PPh2)2}] with a series of small molecules

Reactions of Mo(II)-tetraphosphine complex [MoCl₂(κ⁴-P4)] (2; P4 = meso-o-C₆H₄(PPhCH₂CH₂PPh₂)₂) with a series of small molecules have been investigated. Thus, treatment of 2 with alkynes RCCR′ (R = Ph, R′ = H; R = p-tolyl, R′ = H; R = Me, R′ = Ph) in benzene or toluene gave neutral mono(alkyne) complexes [MoCl₂(RCCR′)(κ³-P4)] containing tridentate P4 ligand, which were converted to cationic complexes [MoCl(RCCR′)(κ⁴-P4)]Cl having tetradentate P4 ligand upon dissolution into CDCl₃ or CD₂Cl₂. The latter complexes were available directly from the reactions of 2 with the alkynes in CH₂Cl₂. On the other hand, treatment of 2 with 1 equiv. of XyNC (Xy = 2,6-Me₂C₆H₃) afforded a seven-coordinate mono(isocyanide) complex [MoCl₂(XyNC)(κ⁴-P4)] (7), which reacted further with XyNC to give a cationic bis(isocyanide) complex [MoCl(XyNC)₂(κ⁴-P4)]Cl (8). From the reaction of 2 with CO, a mono(carbonyl) complex [MoCl₂(CO)(κ⁴-P4)] (9) was obtained as a sole isolable product. Reaction of 9 with XyNC afforded [MoCl(CO)(XyNC)(κ⁴-P4)]Cl (10a) having a pentagonal-bipyramidal geometry with axial CO and XyNC ligands, whereas that of 7 with CO resulted in the formation of a mixture of 10a and its isomer 10b containing axial CO and Cl ligands. Structures of 7 and 9 as well as [MoCl(XyNC)₂(κ⁴-P4)][PF₆](8′) and [MoCl(CO)(XyNC)(κ⁴-P4)][PF₆] (10a′) derived by the anion metathesis from 8 and 10a, respectively, were determined in detail by the X-ray crystallography.     

Syntheses and characterization of η-cyclopentadienyl and η-indenyl ruthenium(II) complexes of arylazoimidazoles: The molecular structure of the complex [(η-C5H5)Ru(PPh3)(C6H5-NN-C3H3N2)]

The complex [(η⁵-C₅H₅)Ru(PPh₃)₂Cl] (1) reacts with several arylazoimidazole (RaaiR′) ligands, viz., 2-(phenylazo)imidazole (Phai-H), 1-methyl-2-(phenylazo)imidazole (Phai-Me), 1-ethyl-2-(phenylazo)imidazole (Phai-Et), 2-(tolylazo)imidazole (Tai-H), 1-methyl-2-(tolylazo)imidazole (Tai-Me) and 1-ethyl-2-(tolylazo)imidazole (Tai-Et), gave complexes of the type [(η⁵-C₅H₅)Ru(PPh₃)(RaaiR′)]⁺ {where R, R′ = H (2), R = H, R′ = CH₃ (3), R = H, R′ = C₂H₅ (4), R = CH₃, R′ = H (5), R, R′ = CH₃ (6), R = CH₃, R′ = C₂H₅ (7)}. The complex [(η⁵-C₉H₇)Ru(PPh₃)₂(CH₃CN)]⁺ (8) undergoes reactions with a series of N,N-donor azo ligands in methanol yielding complexes of the type [(η⁵-C₉H₇) Ru(PPh₃)(RaaiR′)]⁺ {where R, R′ = H (9), R = H, R′ = CH₃ (10), R = CH₃, R′ = H (11), R = CH₃, R′ = C₂H₅ (12)}, respectively. These complexes were characterized by FT IR and FT NMR spectroscopy as well as by analytical data. The molecular structure of the complex [(η⁵-C₅H₅)Ru(PPh₃)(C₆H₅-NN-C₃H₃N₂)]⁺ (2) was established by single crystal X-ray diffraction study.     

Synthesis, structure and electrochemistry of cationic diruthenium complexes of the type [(N∩N)2Ru2(CO)2(μ-CO)2(μ-OOCFc)] containing a ferrocenecarboxylato bridge and two chelating aromatic diimine ligands

The dinuclear bis(ferrocenecarboxylato) complex Ru₂(CO)₄(μ-OOCFc)₂(py)₂ (Fc = ferrocenyl, py = pyridine) was found to react with aromatic diimines (2,2′-dipyridyl, 4,4′-dimethyl-2,2′-dipyridyl, 1,10-phenanthroline, 5-nitro-1,10-phenanthroline, and 5-amino-1,10-phenanthroline) in methanol to give the cationic diruthenium complexes [(N∩N)₂Ru₂(CO)₂(μ-CO)₂(μ-OOCFc)]⁺ (1: N∩N = 2,2′-dipyridyl, 2: N∩N = 4,4′-dimethyl-2,2′-dipyridyl, 3: N∩N = 1,10-phenanthroline, 4: N∩N = 5-nitro-1,10-phenanthroline, 5: N∩N = 5-amino-1,10-phenanthroline), which have been isolated as the hexafluorophosphate salts. The molecular structure of 3, solved by single-crystal X-ray analysis of the tetraphenylborate salt [3][BPh₄], shows a diruthenium backbone bridged by two carbonyl and by one ferrocenecarboxylato ligand, the two 1,10-phenanthroline ligands being in the axial positions. Cyclic voltammetry in dichloromethane reveals for all compounds two successive oxidations due to ferrocene/ferrocenium redox couple and oxidation of the diruthenium core.     

Synthesis of 2-(N-arylimino-κN-methyl)pyrrolide-κN complexes of nickel

2-(N-aryliminomethyl)pyrrole precursors (2,6-R₂-C₆H₃-NCH-2-C₄H₃NH) (R = Me, IH; R = ⁱPr, IIH) were prepared and transformed into their corresponding sodium salts (Na⁺I⁻ and Na⁺II⁻) by treatment with NaH. Both salts readily react with [NiBr₂(DME)] (DME = 1,2-dimethoxyethane) to give the respective bis{2-(N-arylimino-κN-methyl)pyrrolide-κN}nickel(II) complexes (1, 2) in almost quantitative yields. The oxidative addition of IH to [Ni(COD)₂] (COD = 1,5-cyclooctadiene) results in the formation of 3, which is a mono(iminomethylpyrrolide)-η³-(cyclic-allyl)-type organonickel(II) complex. The crystal structure of compound 1 has been established by X-ray diffraction studies.     

Glycal-ruthenium carbonyl clusters: Syntheses, characterization, and anticancer activity

Four new chiral ruthenium carbonyl cluster complexes Ru₃(μ-H)₂(CO)₉(L-2H) (1), Ru₃(μ-H)₂(CO)₇(L-2H)(dppm) (2), Ru₃(μ-H)₂(CO)₇(L-2H)(PPh₃)₂ (3), Ru₃(μ-H)₂(CO)₇(L-2H)(dppe) (4) containing a dehydrogenated form (L-2H) of 3,4,6-tri-O-benzyl-d-galactal (L) as a chiral ligand have been prepared and characterized. The anticancer activity of five compounds 1-4 and Ru₃(μ-H)₂(CO)₉(L-2H) 5 (L = tribenzyl glucal) against six types of human cancer cell lines was studied and compared to cisplatin. Compound 1 was chosen to produce more detailed growth curves based on overall highest activity profile. The structure of compound 2 was established by a single-crystal X-ray diffraction analysis. The structure based on triangular metal framework contains a bridging dehydrogenated tribenzyl galactal ligand bonded in a parallel μ₃-η²-bonding mode and a bridging dppm ligand. Variable-temperature NMR studies show that the two hydride ligands in compounds 1 and 2 are dynamically active on the NMR time scale at room temperature.     

SPh functionalized bridging-vinyliminium diiron and diruthenium complexes

The SPh functionalized vinyliminium complexes [Fe₂{μ-η¹:η³-C_γ(R′)C_β(SPh)C_αN(Me)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] [R = Xyl, R′ = Me, 2a; R = Me, R′ = Me, 2b; R = 4-C₆H₄OMe, R′ = Me, 2c; R = Xyl, R′ = CH₂OH, 2d; R = Me, R′ = CH₂OH, 2e; Xyl = 2,6-Me₂C₆H₃] are generated in high yields by treatment of the corresponding vinyliminium complexes [Fe₂{μ-η¹:η³-C_γ(R′)C_β(H)C_αN(Me)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (1a-e) with NaH in the presence of PhSSPh. Likewise, the diruthenium complex [Ru₂{μ-η¹:η³-C_γ(Me)C_β(SPh)C_αN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (2f) was obtained from the corresponding vinyliminium complex [Ru₂{μ-η¹:η³-C_γ(Me)C_β(H)C_αN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂] (1f). The synthesis of 2c is accompanied by the formation, in comparable amounts, of the aminocarbyne complex [Fe₂{μ-CN(Me)(4-C₆H₄OMe)}(SPh)(μ-CO)(CO)(Cp)₂] (3).The molecular structures of 2d, 2e and 3 have been determined by X-ray diffraction studies.     

A new coordination mode for (pyrid-2-yl)thiolate (L) ligands: Synthesis and characterization of [Ru6(μ3-H)(μ5-κ-L)(μ-CO)(CO)15]

The hexaruthenium cluster complexes [Ru₆(μ₃-H)(μ₅-κ²-L)(μ- CO)(CO)₁₅], HL = 2-mercaptopyridine (1) and 2-mercapto-6-methylpyridine (2), have been prepared by heating [Ru₃(CO)₁₂] with 0.5 equiv. of HL in THF at reflux temperature. An X-ray diffraction study on a crystal of complex 2 has determined that its metallic skeleton, a basal-edge-bridged square pyramid, is hold up by a (6-methylpyrid-2-yl)thiolate ligand. This ligand is attached to the four basal ruthenium atoms of the pyramid through the sulfur atom and to the edge-bridging ruthenium atom through the nitrogen atom. Such a coordination mode is unprecedented for (pyrid-2-yl)thiolate ligands.     

Di- and tri-nuclear molybdenum-palladium complexes bearing strong π-acceptor “P-N-P” ligands, MeN{P(OR)2}2 (R = CH2CF3 or Ph)

The dipalladium complexes, [PdCl(μ-MeN{P(OR)₂}₂)]₂ (R = CH₂CF₃, 1a; Ph, 1b) react with [Mo₂(η⁵-C₅H₅)₂(CO)₆] in boiling benzene to afford the molybdenum-palladium heterometallic complexes, [(η⁵-C₅H₅)(CO)Mo(μ-MeN{P(OR)₂}₂)₂PdCl] (R = CH₂CF₃, 3a; Ph, 3b), [(η⁵-C₅H₅)Mo(μ₃-CO)₂(μ-MeN{P(OR)₂}₂)₂Pd₂Cl], (R = CH₂CF₃, 5a; Ph, 5b), [(η⁵-C₅H₅)(Cl)Mo(μ₂-CO)(μ₂-Cl)(μ-MeN{P(OR)₂}₂)PdCl], (R = CH₂CF₃, 6a; Ph, 6b) and also the mononuclear complex [Mo(CO)Cl(η⁵-C₅H₅)(κ²-MeN{P(OR)₂}₂)], (R = Ph, 4b). These complexes have been separated by column chromatography and are characterised by elemental analysis, IR, ¹H, ³¹P{¹H} NMR data. The structures of 1a, 3a, 4b, 5b and 6a have been confirmed by single crystal X-ray diffraction. The CO ligands in 5b and 6a adopt a semi-bridging mode of bonding; the Mo-CO distances (1.95-1.97 Å) are shorter than the Pd-CO distances (2.40-2.48 Å). The Pd-Mo distances fall in the range, 2.63-2.86 Å. The reaction of [Mo₂(η⁵-C₅H₅)₂(CO)₆] with MeN{P(OPh)₂}₂ in toluene gives [Mo₂(CO)₄(η⁵-C₅H₅)₂(κ¹-MeN{P(OPh)₂}₂)₂] (2) in which the diphosphazane acts as a monodentate ligand.     

Synthesis, X-ray crystal structure and cytotoxicity of a new tetranuclear ruthenium arene complex

The tetranuclear ruthenium arene compound [(cym)₄Ru₄(2)Cl₆]Cl₂ (3) (cym = η⁶-p-cymene, 2 = 1,2-bis(di-N-methylimidazol-2-ylphosphino)ethane) was prepared and characterised by one- and two-dimensional NMR techniques. Its cytotoxicity against four different cell lines was determined and, with an approximate IC₅₀ of >100 μM 3 can be regarded as non-toxic. Its partition coefficient in n-octanol/water (log D_7.4) was also determined. The structures of complex 3 as well as of the related compound [(cym)₂Ru₂(4)Cl₂]Cl₂ (5) (4 = 1,2-bis(di-N-methylimidazol-2-ylphosphino)ethane dioxide) were determined by single crystal structure analysis. Upon oxidation in protic solvents, ligand 2 shows P-C bond cleavage reactions to yield P,P′-bis(N-methylimidazol-2-yl)ethylene diphosphinic acid (6).     

Methyl-oxygen bond cleavage in hemilabile phosphine-ether ligand of ruthenium(II) complexes

The preparation and characterization are described for four ruthenium(II) complexes containing hemilabile phosphine-ether ligand o-(diphenylphosphino)anisole (Ph₂PC₆H₄OMe-o) and/or bidentate ligand diphenylphosphino-phenolate ([Ph₂PC₆H₄O-o]⁻) Ru(RCN)₂(κ²-Ph₂PC₆H₄O-o)₂ (1a: R = Me; 1b: R = Et) and [Ru(RCN)₂(κ²-Ph₂PC₆H₄O-o)(κ²-Ph₂PC₆H₄OMe-o)](PF₆) (2a: R = Me; 2b: R = Et). The ruthenium(II) phosphine-ether complexes undergo mild methyl-oxygen bond cleavage. Two different kinds reaction mechanism are proposed to describe the methyl-oxygen bond cleavage, one involving attack of anionic nucleophiles and another involving the phosphine. The new reactions define novel routes to phosphine-phenolate complexes. The structures of complexes 1a, 1b and 2a were confirmed by X-ray crystallography.     

Formation of multifunctional ligands by nucleophilic addition of alcohols and thiols to the alkyne groups in compound C5H5FeC5H4CCSCCH: Reactivity studies

The multifunctional ligands [(Z)-FcCCSC(H)C(H)XR] [X = O, R = Me (2a); X = O, R = Et (2b); X = S, R = Ph (3); X = S, R = C₆F₅ (5)] and [(Z,Z)-Fc(SR)CC(H)SC(H)C(H)SR] [R = Ph (4), C₆F₅ (6)] have been prepared through hydroalkoxylation and hydrothiolation processes of the alkyne groups in the compound FcCCSCCH 1. Reactions between compound 3 and the carbonyl metals Co₂(CO)₈, Os₃(CO)₁₀(NCMe)₂ and Fe₂(CO)₉ have allowed the synthesis of the polynuclear compounds [(Z)-{Co₂(CO)₆}(μ-η²-FcCCSC(H)C(H)SPh)] 9, [(Z)-Os₃(CO)₉(μ-CO){μ₃-η²-FcCCSC(H)C(H)(SPh)}] 10 and [(Z)-{Fe₃(CO)₉}[μ₃,η³-(CCS)-FcCCSC(H)C(H)(SPh)] 11. All the compounds have been characterized by elemental analysis, ¹H and ¹³C{¹H} NMR spectroscopy, mass spectrometry and the crystal structure of compounds [(Z)-FcCCSC(H)C(H)OMe] 2a and [{Co₂(CO)₆}₂(μ-η²:η²-FcCCSCCSiMe₃)] 7 have been solved by X ray diffraction analysis.     

Hydride addition at μ-vinyliminium ligand obtained from disubstituted alkynes

New μ-vinylalkylidene complexes cis-[Fe₂{μ-η¹:η³-C_γ(R′)C_β(R″)C_αHN(Me)(R)}(μ-CO)(CO)(Cp)₂] (R = Me, R′ = R″ = Me, 3a; R = Me, R′ = R″ = Et, 3b; R = Me, R′ = R″ = Ph, 3c; R = CH₂Ph, R′ = R″ = Me, 3d; R = CH₂Ph, R′ = R″ = COOMe, 3e; R = CH₂ Ph, R′ = SiMe₃, R″ = Me, 3f) have been obtained b yreacting the corresponding vinyliminium complexes [Fe₂{μ-η¹:η³-C_γ(R′)C_β(R″)C_αN(Me)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (2a-f) with NaBH₄. The formation of 3a-f occurs via selective hydride addition at the iminium carbon (C_α) of the precursors 2a-f. By contrast, the vinyliminium cis-[Fe₂{μ-η¹:η³-C_γ (R′) = C_β(R″)C_α = N(Me)(Xyl)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R′ = R″ = COOMe, 4a; R′ = R″ = Me, 4b; R′ = Prⁿ, R″ = Me, 4c; Prⁿ = CH₂CH₂CH₃, Xyl = 2,6-Me₂C₆H₃) undergo H⁻ addition at the adjacent C_β, affording the bis-alkylidene complexes cis-[Fe₂{μ-η¹:η²-C(R′)C(H)(R″)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂], (5a-c). The cis and trans isomers of [Fe₂{μ-η¹:η³-C_γ(Et)C_β(Et)C_αN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (4d) react differently with NaBH₄: the former reacts at C_α yielding cis-[Fe₂{μ-η¹:η³-C_γ(Et)C_β(Et)C_αHN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂], 6a, whereas the hydride attack occurs at C_β of the latter, leading to the formation of the bis alkylidene trans-[Fe₂{μ-η¹:η²-C(Et)C(H)(Et)CN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂] (5d). The structure of 5d has been determined by an X-ray diffraction study. Other μ-vinylalkylidene complexes cis-[Fe₂{μ-η¹:η³-C_γ(R′)C_β(R″)C_αHN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂], (R′ = R″ = Ph, 6b; R′ = R″ = Me, 6c) have been prepared, and the structure of 6c has been determined by X-ray diffraction. Compound 6b results from treatment of cis-[Fe₂{μ-η¹:η³-C_γ(Ph)C_β(Ph)C_αN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (4e) with NaBH₄, whereas 6c has been obtained by reacting 4b with LiHBEt₃. Both cis-4d and trans-4d react with LiHBEt₃ affording cis-6a.     

C-C bond formation through olefin-thiocarbyne coupling in diiron complexes

The bridging diiron thiocarbyne complex [Fe₂{μ-CS(Me)}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃] (1) reacts with activated olefins (methyl acrylate, acrylonitrile, styrene, diethyl maleate), in the presence of Me₃NO and NaH, to give the corresponding μ-allylidene complexes [Fe₂{μ-η¹:η³-C_α(SMe)C_β(R′)C_γ(H)(R″)} (μ-CO)(CO)(Cp)₂] (R″ = CO₂Me, R′ = H, 3a; R″ = CN, R′ = H, 3b; R″ = C₆H₅, R′ = H, 3c; R″ = R′ = CO₂Et, 3d). The coupling reaction of olefin with thiocarbyne is regio- and stereospecific, leading to the formation of only one isomer. C-C bond formation occurs between the less substituted alkene carbon and the thiocarbyne. Moreover, olefinic hydrogens of the bridging ligands are mutually trans.The reactions of 3a-b with MeSO₃CF₃ result, selectively, in the formation of the cationic μ-sulphonium allylidene complexes [Fe₂{μ-η¹:η³-C_α(SMe₂)C_β (H)C_γ(H)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = CO₂Me, 4a; R = CN, 4b). Compound 4a undergoes displacement of the SMe₂ group by nucleophiles such as NaBH₄, NBu₄CN and NaOMe, affording the complexes [Fe₂{μ-η¹:η³-C_α(R)C_β (H)C_γ(H)(CO₂Me)}(μ-CO)(CO)(Cp)₂] (R = H, 5a; R = CN, 5b; R = OMe, 5c), respectively. The molecular structures of 3a and 5a have been determined by X-ray diffraction studies.