Chiral self-assembly of triorganotin complexes: Syntheses, characterization, crystal structures and antitumor activity of organotin(IV) complexes containing (R)-(+)-methylsuccinic acid, (S)-(+)-methylglutaric acid and l-(−)-malic acid ligands

Six new chiral triorganotin(IV) complexes, {(R₃Sn)₂[C₃H₆(COO)₂]}_n (R = Me: 1; Bu: 2), {(R₃Sn)₂[C₄H₈(COO)₂]}_n (R = Me: 3; Bu: 4), and {(R₃Sn)₂[C₂H₄O(COO)₂]}_n (R = Me: 5; Bu: 6) have been prepared by treatment of (R)-(+)-methylsuccinic acid, (S)-(+)-methylglutaric acid and l-(−)-malic acid, with the corresponding R₃SnCl (R = Me, Bu) and sodium ethoxide in methanol. All the complexes were characterized by elemental analysis, FT-IR, NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy and TGA. Except for 3, all of the complexes were also characterized by X-ray crystallography. The structural analyses reveal that complexes 1 and 5 have 2D network structures in which (R)-(+)-methylsuccinic acid and l-(−)-malic acid act as tetradentate ligands coordinated to trimethyltin(IV) ions. Complexes 2 and 4 have 3D metal-organic framework structures in which the deprotoned acids serve as tetradentate ligands. Complex 6 adopts a 1D zigzag chain structure and forms a 2D supramolecular framework through intermolecular C-H?O interactions. In addition, the antitumor activities of complexes 1-6 have been studied. We also have measured the specific rotation of the chiral dicarboxylic acids and the organotin derivatives.     

Insertion of ethyl diazoacetate into the platinum–carbon bond of Pt(diphosphine)(halide)(aryl) complexes. X-ray structure of the Pt{(2<Emphasis Type="BoldItalic">S</Emphasis>,4<Emphasis Type="BoldItalic">S</Emphasis>)-bdpp)}I(Ph) complex

Pt(diphosphine)X(aryl) complexes [diphosphine = 1,3-bis(diphenylphosphino)propane (dppp), 2,4-bis(diphenylphos phino)pentane (bdpp); aryl = phenyl, 2-thiophenyl; X = Cl, I] have been reacted with ethyl diazoacetate in chloroform. It has been revealed by in␣situ n.m.r. studies that the starting compounds insert the carbene, formed from ethyl diazoacetate, into the Pt–aryl group resulting in Pt(diphosphine)X{CH(aryl)COOC₂H₅}. Depending on the reaction conditions (reaction time, ratio of the reactants) and the ligands various side-reactions have been observed: (i) the formation of Pt(diphosphine)X₂ in chloroform, (ii) the insertion of the :CHCOOC₂H₅ fragment into the Pt–halide bond of the dihalogeno complexes Pt(diphosphine)X₂ resulting in the exclusive formation of Pt(diphosphine)X(CHXCOOC₂H₅). Diastereoselective insertion reactions have been observed in the presence of (S,S)-bdpp as diphosphine. The Pt{(S,S)-bdpp)}I(Ph) complex has been characterized by X-ray crystallography.     

(E, E)S, S′-bis(2-benzimidazolylmethyl) dithioglyoxime, synthesis and characterization of heterotrinuclear complexes of and determination of their metal contents by EDXRF analysis

A vicinal dioxime ligand with two 2-benzimidazolylmethyl groups, namely S, S′-bis(2-benzimidazolylmethyl) dithioglyoxine (H₂L) and its axially pyridine and 2,6-dimethyl pyridine bonded Co(III) complexes were prepared according to prior literature [Y. Gök, S.Z. Y?ld?z, Synth. React. Inorg. Met-Org. Chem. 22 (9) (1992) 1327]. BF₂⁺ bridged Co(III) complexes have been synthesized via the hydrogen-bridged Co(III) complexes by using borontrifloride ethyl ether complex. Heterotrinuclear complexes have been prepared by the reaction of these more soluble BF₂-capped Co(III) complexes with stoichiometric amount of CdCl₂ · H₂O and NiCl₂ · 6H₂O salts. Using ¹H, ¹³C NMR, IR and MS spectral data and elemental analysis, the structures of the complexes were identified. Qualitative and quantitative determination of Co, Ni and Cd contents of the heterotrinuclear complexes have been investigated by energy dispersive X-ray fluorescence (EDXRF) method. An annular 50 mCi ²⁴¹Am radioactive source emitting 59.543 keV photons was used for excitation and Si(Li) detector having 157 eV FWHM at 5.9 keV was used for intensity measurements.     

Synthesis,spectroscopic and electrochemical characterization of copper(I) complexes with functionalized pyrazino[2,3-f]-1,10-phenanthroline

The present work reports the synthesis and spectroscopic and electrochemical characterization of homoleptic copper(I) complexes with substituted pirazino [2,3-f]-1,10-phenanthroline, RpplR′, (R = H, Me, COOH or COOMe, and R′ = H, Me) as ligand. The ligand ppl works as an acceptor of electronic density, which is delocalized mainly in the quinoxaline part of its structure. The UV–Vis spectra show that all the complexes display bands in the range 400–650 nm, which are MLCT in character. The λ_max and extinction coefficients of the MLCT band at 450 nm and the LC band do not change significatively when varying the R substituent. Nevertheless, the intensity of the shoulder around 500 nm does change; this absorption has been related to either a static or dynamic flattening distortion of the complex D_2d → D₂ symmetry. The cyclic voltammetry of the complexes shows irreversible redox processes with E_p values that do not follow the tendency expected from the donor/acceptor character of the substituents on the ligand. All the complexes studied showed no emission both in acetonitrile and dichloromethane as solvent at room temperature and under argon atmosphere.     

Formation and structures of Pd(II) N,S-heterocyclic carbene-pyridyl mixed-ligand complexes

Mononuclear mixed-ligand complexes of Pd(II) containing a N,S-heterocyclic carbene (NSHC) with a secondary alkyl N-substituent and pyridyl ligand, with the general formula [PdI₂(C₁₀H₁₁NS)L] (C₁₀H₁₁NS = 3-isopropylbenzothiazolin-2-ylidene; L = pyridine, 2-aminopyridine, 3-iodopyridine and 4-tert-butyl-pyridine) have been synthesized and characterized by X-ray single-crystal crystallography. Both solution and solid-state structures, as evident from their ¹H NMR spectra and X-ray structures, show anagostic γ-hydrogen interactions of metal with methine of the substituent on the carbene or pyridyl ligand giving 5-membered-chelate-like structures.     

Synthesis and coordination chemistry of new tetradentate N2S2 donor Schiff-base ligand ca2-dapte: Mononuclear and dinuclear copper(I) complexes [Cu(ca2dapte)]ClO4 and [{Cu(PPh3)(X)}2(ca2dapte)] (X = I and Br)

A mononuclear copper(I) complex, [Cu(ca₂dapte)]ClO₄ (1), and two dinuclear copper(I) complexes, [{Cu(PPh₃)(X)}₂(ca₂dapte)] (X = I (2) and Br (3)), of a new tetradentate N₂S₂ donor Schiff-base ligand ca₂dapte have been prepared (ca₂dapte = N,N′-bis(trans-cinnamaldehyde)-1,2-di(o-iminophenylthio)ethane). These compounds have been characterized by elemental analyses (CHN), FT-IR, UV–Vis and ¹H NMR spectroscopy. The crystal structures of these copper(I) complexes have been determined by single-crystal X-ray diffraction. The coordination geometry around Cu(I) centers in these complexes is a distorted tetrahedron. The ca₂dapte is coordinated to Cu(I) as a tetradentate ligand in 1, while it acts as a bis-bidentate bridging ligand in 2 and 3.     

Mononuclear ruthenium(II) complexes bearing the (S,S)-Pr-pybox ligand

The complexes trans-[RuCl₂(L){(S,S)-ⁱPr-pybox}] ((S,S)-ⁱPr-pybox = 2,6-bis[4′-(S)-isopropyloxazolin-2′-yl]pyridine, L = PMe₃ (1), P(OMe)₃ (2), PPh₂(CH₂CHCH₂) (3), CNBn (5), CNCy (6) and MeCN (7)) have been synthesized by substitution of ethylene on the precursor trans-[RuCl₂(η²-C₂H₄){(S,S)-ⁱPr-pybox}]. This complex also reacts with cyclooctadiene (cod) or norbornadiene (nbd) and NaPF₆, in refluxing methanol, giving the coordination compounds [RuCl(η⁴-cod){(S,S)-ⁱPr-pybox}][PF₆] (8) and [RuCl(η⁴-nbd){(S,S)-ⁱPr-pybox}][PF₆] (9). The structures of complexes [RuCl(CO)(PPh₃)(H-pybox)][BF₄] (H-pybox = 2,6-bis(dihydrooxazolin-2′-yl)pyridine) (4), 6 and 8, have been resolved by X-ray diffraction methods. The catalytic activity of the new complexes in transfer hydrogenation of acetophenone has also been examined.     

Syntheses and structures of N-polyfluorophenyl- and N,N′-bis(polyfluorophenyl)ethane-1,2-diaminato(1- or 2-)platinum(II) complexes

The reaction of [PtX₂(L)] (X = Cl, Br, I; L = NH₂CH₂CH₂NY₂; Y = Et, Me) with thallium(I) carbonate and a polyfluorobenzene (RF) in pyridine (py) yields the platinum(II) complexes, [Pt{N(R)CH₂CH₂NY₂}X(py)] (R = C₆F₅, 4-HC₆F₄, 4-BrC₆F₄, or 4-IC₆F₄, Y = Et (1), Me (2), X = Cl, Br or I) in an improved synthesis. From the reaction of [PtCl₂(H₂NCH₂)₂)] with Tl₂CO₃ and 1,2,3,4-tetrafluorobenzene or 2-bromo-1,3,4,5-tetrafluorobenzene in py, the new complexes [Pt(NRCH₂)₂(py)₂] (3) (R = C₆H₂F₃-2,3,6 and C₆HBrF₃-2,3,5,6) have been isolated but the latter preparation also gave product(s) with a 4-bromo-2,3,5-trifluorophenyl group. From an analogous preparation in 4-ethylpyridine (etpy), [Pt(N(4-HC₆F₄)CH₂)₂(etpy)₂] (4) was obtained. The X-ray crystal structures of (3) (R = C₆HBrF₃-2,3,5,6) and (4) were determined as well as that of the previously prepared (3) (R = 4-BrC₆F₄) and a more precise structure of (3) (R = 4-HC₆F₄) has been obtained.     

Insertion of tin(II) bromide into Pt–X (X = Cl,Br) bond of dimethylplatinum(IV) complexes: A novel polymorphic form of [PtBr2(bpy)]

The platinum(II) complex [PtMe₂(bpy)] (bpy = 2,2′-bipyridine) reacted with a large excess of dihaloalkanes X(CH₂)_nX (n = 1, X = Cl; n = 4, X = Br) to form the platinum(IV) complexes [PtMe₂X{(CH₂)_nX}(bpy)] (n = 1, X = Cl, 1a; n = 4, X = Br, 1b). The reaction of complexes 1a and 1b with SnBr₂ resulted in insertion of SnBr₂ into Pt–X (X = Cl, Br) bond to afford the trihalostannyl complexes [PtMe₂(SnBr₂X){(CH₂)_nX}(bpy)] (n = 1, X = Cl, 2a; n = 4, X = Br, 2b). The synthesis of such trihalostannylplatinum(IV) complexes is reported for the first time. The complex 2a was decomposed in CH₂Cl₂ solution and single crystals of [PtBr₂(bpy)] (3a) were obtained. The X-ray structure determination of 3a revealed a new polymorphic form of [PtBr₂(bpy)]. The molecules undergo a remarkable stacking along the b-axis to form a zigzag Pt?Pt?Pt chain containing both short (3.799 Å) and long (5.175 Å) Pt?Pt separations through the crystal. The crystal structure is compared to that of the yellow modification of [PtBr₂(bpy)].     

The reaction of the group-13 alkyls ER3 (E = Al, Ga, In; R = CH2t-Bu, CH2 SiMe3) with the platinum-complex [(dcpe)Pt(H)(CH2t-Bu)]

The reactions of the sterically demanding group-13 alkyls ER₃ (E = Al, Ga, In; R = CH₂t-Bu, CH₂SiMe₃) with the platinum-complex [(dcpe)Pt(H)(CH₂t-Bu)] were re-investigated. The bimetallic compounds [(dcpe)Pt(ER₂)(R)] (3: E = Ga, R = CH₂SiMe₃; 5: E = In, R = CH₂t-Bu; dcpe = bis(dicyclohexylphosphino)ethane) with direct σ(Pt-E) bonds were obtained by oxidative addition of an E-C bond to the coordinatively unsaturated fragment [(dcpe)Pt] produced in situ by thermolysis of the starting complex [(dcpe)Pt(CH₂t-Bu)(H)]. The single crystal structure determination reveals a Pt-Ga bond length of 2.376(2) Å and a Pt-In bond length of 2.608(1) Å. All new compounds were characterised by elemental analysis, ³¹P and ¹⁹⁵Pt NMR spectroscopy. Interestingly, the Pt-Ga compound 3 slowly transforms into the platinum alkyl/hydride isomer {(dcpe)Pt(μ₂-H)[CH₂Si(CH₃)₂ CH₂Ga(CH₂SiMe₃)₂]} (4) during crystallization from solution at room temperature. The X-ray single crystal structure analysis revealed both complexes 3 and 4 coexisting in the unit cell in a 1:1 relation. The inaccessibility of analytically pure samples of the Pt-Al complex {(dcpe)Pt[Al(CH₂t-Bu)₂](CH₂t-Bu)} (6), postulated as intermediate of the reaction of [(dcpe)Pt(H)(CH₂t-Bu)] with Al(CH₂t-Bu) on the basis of ³¹P and ¹⁹⁵Pt NMR data, is attributed to an enhanced tendency to isomerisation into the alkyl/hydride Pt/Al congener of 4. A brief DFT analysis of the bonding situation of the model complex [(dhpe)Pt(GaMe₂)(Me)] (1M) revealed, that the contribution of π(Pt-Ga) back-bonding is negligible.     

Coordination modes of 1,2,3,4-tetrahydro-1,4-diphenyl-1,4-benzodiphosphinine (bedip) to Pt and Pd metal ions: Synthesis and structural characterization of mono- and bi-nuclear complexes

Within this study, coordination properties of the cyclic diphosphine 1,2,3,4-tetrahydro-1,4-diphenyl-1,4-benzodiphosphinine (bedip) are investigated, through the preparation of neutral and cationic Pt(II), Pt(IV) and Pd(II) complexes. The diphosphine acts as bridging ligand in the neutral Pt(II) and Pd(II) complexes, affording [MX(CH₃)(μ-bedip)]₂ (X = Cl, Br, I, CH₃) species. Chelation is observed in all the remaining complexes. The molecular structures of [PtX(CH₃)(μ-bedip)]₂ (X = Br, I) and [PtI(CH₃)₃(bedip)] are also determined.     

Pd(0) and Pd(II) derivatives with heteroannularly bridged chiral ferrocenyl diphosphine ligands - A stereochemical analysis

The ligands (S_c, S_p)-1-diphenylphosphino-2,1′-(1-dicyclohexylphosphinopropanediyl)ferrocene, (S_c, S_p)-PP^CyPF, and (S_c, S_p)-1-diphenylphosphino-2,1′-(1-diphenylphosphinopropanediyl)ferrocene, (S_c, S_p)-PP^PhPF, have been used in the synthesis of the new Pd(0) and Pd(II) derivatives [Pd(PP^CyPF)(DMFU)] (1) (DMFU = dimethylfumarate), [Pd(PP^CyPF)(MA)] (2) (MA = maleic anhydride), [Pd(η³-2-Me-C₃H₄)(PP)]OTf (PP = PP^CyPF, 3; PP^PhPF, 4) (OTf = triflate), [PdRR′(PP)] (R = Me, R′ = Cl, PP = PP^CyPF, 5, PP^PhPF, 6; R = R′ = Me, PP = PP^CyPF, 7, PP^PhPF, 8; R = R′ = C₆F₅, PP = PP^CyPF, 9, PP^PhPF, 10). The molecular structure of 7 has been determined by X-ray diffraction. In the cases of complexes 1-4 two isomers are formed depending on the orientation of the ancillary ligand with respect to the ferrocenyl core. The stereochemistry of these complexes has been determined. In complex 6 the two possible isomers are obtained whereas in complex 5 the derivative with the Me group trans to PPh₂ is selectively formed. Restricted rotation of the pentafluorophenyl groups with respect to the Pd-C bond has been found in 9 and 10. In all derivatives the conformation of the ferrocenyl ligand is the same as that seen by X-ray diffraction and deduced from NMR data.     

Experimental and theoretical studies on inversion dynamics of dichloro(l-difluoromethionine-N,S)platinum(II) and dichloro(l-trifluoromethionine-N,S)platinum(II) complexes

Fluorinated analogues of methionine such as l-S-(difluoromethyl)homocysteine (l-difluoromethionine; DFM) and l-S-(trifluoromethyl)homocysteine (l-trifluoromethionine; TFM) have been demonstrated to be interesting analogues for incorporation into peptides and proteins. The presence of the fluorine nucleus adjacent to the sulfur atom in the side chain not only serves to alter the nucleophilicity and electron density of the sulfur atom but it can function as an important NMR spectroscopic (¹⁹F) probe. Additional information on the properties of these fluorinated amino acid analogues was obtained by studying their interactions with dipotassium tetrachloroplatinate (K₂PtCl₄). The resulting complexes, dichloro(l-difluoromethionine-N,S)platinum(II) and dichloro(l-trifluoromethionine-N,S)platinum(II) were investigated with respect to their sulfur inversion rates utilizing dynamic NMR methods. Inversion barriers for the DFM- and TFM-platinum complexes were experimentally determined to be 16.4 ± 0.2 and 18 ± 1 kcal/mol, respectively. Density functional calculations at the B3LYP/SDD level were also performed to model the structures and energies of the ground and transition states for these complexes.     

Structure and magnetism of mono-, di-, and trinuclear benzoato cobalt(II) complexes

Three cobalt(II) - benzoato (bz) complexes have been prepared and structurally characterized. In the mononuclear complex trans-[Co(bz)₂(H₂O)₂(nca)₂] the benzoato ligand is unidentate (nca = nicotinamide). The dinuclear complex [(μ₂-bz)₄{Co(qu)}₂] is a structural analog of the copper acetate (qu = quinoline) where four bidentate benzoato ligands link two cobalt(II) pentacoordinate centers. The trinuclear complex of the composition [Co₃(bz)₆(inca)₆] contains a central hexacoordinate {(bz)₂Co(inca)₂(bz)₂} unit in which the bidentate benzoato ligands held the central and peripheral cobalt(II) centers (inca = iso-nicotinamide); the peripheral hexacoordinate {(bz)Co(inca)₂<} units contain the terminal benzoato ligand in its bidentate function. The magnetic susceptibility data down to T = 2 K and the magnetization data up to B = 7 T reveal a considerable magnetic anisotropy due to the single-ion zero-field splitting.     

Preparation,spectroscopic characterization and X-ray crystal and molecular structures of nickel(II), copper(II) and zinc(II) complexes of the Schiff base formed from isatin and S-methyldithiocarbazate (Hisa-sme)

Complexes of general formula, [M(isa-sme)₂] · n(solvate) [M = Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺; isa-sme = monoanionic form of the Schiff base formed by condensation of isatin with S-methyldithiocarbazate; n = 1 or 1.5; solvate = MeCN, DMSO, MeOH or H₂O] have been synthesized and characterized by a variety of physicochemical techniques. An X-ray crystallographic structure determination of the [Ni(isa-sme)₂] · MeCN complex reveals a six-coordinate, distorted octahedral geometry. The two uninegatively charged, tridentate, Schiff base ligands are coordinated to the nickel(II) ion meridionally via the amide O-atoms, the azomethine N-atoms and the thiolate S-atoms. By contrast, the crystal structure of [Zn(isa-sme)₂] · MeOH shows a four-coordinate distorted tetrahedral geometry. The two dithiocarbazate ligands are coordinated as N, S bidentate chelates with the amide O-atom not coordinated. The structure of the copper(II) complex [Cu(isa-sme)₂] · DMSO is complicated and comprises two different complexes in the asymmetric unit, one four- and the other five-coordinate. The four-coordinate copper(II) has a distorted (flattened) tetrahedral geometry as seen in the Zn(II) analogue whereas the five-coordinate copper(II) has a distorted square-pyramidal geometry with one ligand coordinated to the copper(II) ion as a tridentate (N, S, O) ligand and the other coordinated as a bidentate N, S chelate. EPR spectroscopy indicates that in solution only one form is present, that being a distorted tetrahedral complex.     

Formation and crystal structures of [(alkoxy)bis(pyridin-2-yl)methanolato-N,O,N]tin(IV) complexes

Reactions of bis(pyridin-2-yl)ketone with tin tetrahalides, SnX₄ (X = Cl or Br), or organotin trichlorides, R^′SnCl₃ (R^′ = Ph, Bu or CH₂CH₂CO₂Me), in ROH (R = Me or Et) readily produces RObis(pyridin-2-yl)methanolato)tin complexes, [5: RO(py)₂C(OSnX₃)] (5: R,X = Me,Cl; Et,Cl; Et,Br) or [6: MeO(py)₂C(OSnCl₂R^′)] (R^′ = Ph, Bu, CH₂CH₂CO₂Me). In addition, halide exchange reaction between SnI₄ and (5: R,X = Me,Cl) occurred to give (5: R,X = Me,I). The crystal structures of six tin(IV) derivatives indicated, in all cases, a monoanionic tridentate ligand, [RO(py)₂C(O⁻)-N,O,N], arranged in a fac manner about a distorted octahedral tin atom. The Sn–O and Sn–N bonds lengths do not show much variation amongst the six complexes despite the differences in the other ligands at tin.     

Synthesis, structure, photochromism and DFT calculations of copper(I)-triphenylphosphine halide complexes of thioalkylazoimidazoles

[Cu(SRaaiNR′)(PPh₃)X] complexes are synthesized by the reaction of CuX (X = Cl, Br, I), triphenylphosphine and 1-alkyl-2-[(o-thioalkyl)phenylazo]imidazole (SRaaiNR′). The single crystal X-ray structure of [Cu(SEtaaiNH)(PPh₃)I] (SEtaaiNH = 2-[(o-thioethyl)phenylazo]imidazole) shows a distorted tetrahedral geometry of the copper center with bidentate, N(azo), N(imidazole) chelation of SEtaaiNH and coordination from PPh₃ and iodine. These complexes show a trans-to-cis isomerization upon irradiation with UV light. The reverse transformation, cis-to-trans isomerization, is very slow with visible light irradiation and is thermally accessible. The quantum yields (?_t→c) of the trans-to-cis isomerization of [Cu(SRaaiNR′)(PPh₃)X] are lower than the free ligand values. This is due to the increased mass and rotor volume of the complexes compared to the free ligand data. The rate of isomerization follows the order: [Cu(SRaaiNR′)(PPh₃)Cl] < [Cu(SRaaiNR′)(PPh₃)Br] < [Cu(SRaaiNR′)(PPh₃)I]. The activation energy (E_a) of the cis-to-trans isomerization is calculated by a controlled temperature reaction. DFT computation of representative complexes has been used to determine the composition and energy of the molecular levels.     

Diphenylphosphino(phenyl pyridin-2-yl methylene)amine palladium(II) complexes: Chemoselective alkene hydrocarboxylation initiators

The heteroditopic, P-N-chelating ligand diphenylphosphino(phenyl pyridin-2-yl methylene)amine (1) has been synthesised via a simple ‘one-pot’ procedure and its donor characteristics assessed. The neutral [MX(Y)(1-κ²-P-N)] (3, M = Rh, X = Cl, Y = CO; 4, M = Pd, X = Y = Cl; 5, M = Pd, X = Cl, Y = Me; 6, M = Pt, X = Y = Cl; 7, M = Pt, X = Cl, Y = Me; 8, M = Pt, X = Y = Me) and cationic [Pd(Me)(MeCN)(1-κ²-P-N)][Z] (9, Z = B{3,5-(CF₃)₂-C₆H₃}4; 10, Z = PF₆) complexes of 1 have been prepared and characterised. The solid-state structures of complexes 3, 4, 6 and 7 have been established by X-ray crystallography. Reactions of [PdCl(Me)(1-κ²-P-N)] towards CO and ^tBuNC have been investigated, affording the corresponding η¹-acyl (12) and -iminoacyl (14) complexes, respectively. Similar insertion chemistry is observed for the cationic derivative 9. Treatment of the acyl complex 12 with ethene at elevated pressure establishes an equilibrium between the starting material and the product resulting from insertion, 13. Under catalytic conditions, combination of palladium(II) with 1 in MeOH affords a selective initiator for the formation of 4-oxo-hexanoic acid methyl ester (15) from CO/ethene (38 bar, 90 °C).     

New mercury(II) and cadmium(II) complexes with (p-methylbenzoyl)methylene triphenylphosphorane: Synthesis,spectroscopic and structural characterization

Reaction of Ph₃PCHCOC₆H₄Me (L), with HgX₂ and CdCl₂·H₂O in methanol with equimolar ratios give binuclear complexes of the type [MX(μ-X){CH(PPh₃)C(O)C₆H₄Me}]₂ (M = Hg; X = Cl (1), Br (2), I (3), M = Cd; Cl(4)). The bridge-splitting reaction of binuclear complexes [MX(μ-X){CH(PPh₃)C(O)C₆H₄Me}]₂ by dimethyl sulfoxide (DMSO) yields the mononuclear complexes [MX₂{CH(PPh₃)C(O)C₆H₄Me}(OSMe₂)] (M = Hg; X = Cl (5), Br (6), I (7), M = Cd; Cl (8)). The characterization of these complexes was carried out by elemental analysis and FT-IR, ¹H, ³¹P, and ¹³C NMR spectroscopies. C-coordination of ylide and O-coordination of DMSO are demonstrated by single-crystal X-ray analysis of mononuclear complex of [HgBr₂{CH(PPh₃)C(O)C₆H₄Me}(OSMe₂)] (6). Complex 6 is monomeric with tetrahedral geometry around the metal ion.