Bis(pyrazolyl) palladium(II), platinum(II) and gold(III) complexes: Syntheses, molecular structures and substitution reactions with l-cysteine

A series of pyrazolyl palladium(II), platinum(II) and gold(III) complexes, [PdCl₂(3,5-R₂bpza)] {R = H (1), R = Me (2), bpza = bis-pyrazolyl acetic acid}, [PtCl₂(3,5-R₂bpza)] {R = H (3a), R = Me (4)}, [AuCl₂(3,5-R₂bpza)]Cl {R = H (5a), R = Me (6a)} and [PdCl₂(3,5-R₂bpzate)] {R = Me (7)} have been synthesised and structurally characterised. Single crystal X-ray crystallography showed that the pyrazolyl ligands exhibit N^N-coordination with the metals. Anticancer activities of six complexes 1-6a were investigated against CHO cells and were found to have low activities. Substitution reactions of selected complexes 1, 2, 3a and 5a with l-cysteine show that the low anticancer activities compounds and that the rate of substitution with sulfur-containing compounds is not the cause of the low anticancer activities.     

Synthesis, characterization and cytotoxic properties of platinum(II) complexes containing the nucleosides adenosine and cytidine

Cytidine (cyt) and adenosine (ado) react with cis-[L₂Pt(μ-OH)]₂(NO₃)₂ (L = PMe₃, PPh₃) in various solvents to give the nucleoside complexes cis-[L₂Pt{cyt(− H),N³N⁴}]₃(NO₃)₃ (L = PMe₃, 1),cis-[L₂Pt{cyt(− H),N⁴}(cyt,N³)]NO₃ (L = PPh₃, 2), cis-[L₂Pt{ado(− H),N¹N⁶}]₂(NO₃)₂ (L = PMe₃, 3) and cis-[L₂Pt{ado(− H),N⁶N⁷}]NO₃ (L = PPh₃, 4). When the condensation reaction is carried out in solution of nitriles (RCN, R = Me, Ph) the amidine derivatives cis-[(PPh₃)₂PtNH=C(R){cyt(− 2H)}]NO₃ (R = Me, 5a; R = Ph, 5b) and cis-[(PPh₃)₂PtNH=C(R){ado(− 2H)}]NO₃ (R = Me, 6a: R = Ph, 6b) are quantitatively formed. The coordination mode of these nucleosides, characterized in solution by multinuclear NMR spectroscopy and mass spectrometry, is similar to that previously observed for the nucleobases 1-methylcytosine (1-MeCy) and 9-methyladenine (9-MeAd). The cytotoxic properties of the new complexes, and those of the nucleobase analogs, cis-[(PPh₃)₂PtNH=C(R){1-MeCy(− 2H)}]NO₃ (R = Me, 7a: R = Ph, 7b), cis-[(PPh₃)₂PtNH=C(R){9-MeAd(− 2H)}]NO₃ (R = Me, 8a: R = Ph, 8b) have been investigated in a wide panel of human cancer cells. Interestingly, whereas the Pt(II) nucleoside complexes (1-4) did not show appreciable cytotoxicity, the corresponding amidine derivatives (7a, 7b, 8a, 8b, 5b, and 6b) exhibited a significant in vitro antitumor activity.     

Group 3 complexes incorporating (furyl)-substituted disilazide ligands

A series of mono- and bis-amide scandium and yttrium compounds incorporating the furyl-substituted disilazide ligand, [N{SiMe₂R}₂]⁻ {i} (where R = 2-methylfuryl) have been synthesized. The compounds Sc{i}Cl₂ (1), Sc{i}(CH₂SiMe₃)₂ (2) and Sc{i}(OAr)₂ (3) were made from suitable scandium starting materials employing either a salt metathesis protocol with Li{i} or via protonolysis of Sc-C bonds by the neutral amine H{i}. The thermally unstable bis-alkyl yttrium compound, ‘Y{i}(CH₂SiMe₃)₂^’ was isolated as the bis-THF adduct (4) and the bis-aryloxide Y{i}(OAr)₂ (5) was synthesized by elimination of LiOAr from Y(OAr)₃. The bis-amide complex Y{i}₂Cl (6) and conversion to a rare example of an yttrium benzyl compound Y{i}₂(CH₂Ph) (7) are described. The yttrium cation, [Y{i}₂]⁺, was synthesized by benzyl abstraction from 7 using B(C₆F₅)₃. Structural characterization of representative examples show variation in the coordination modes for amide ligand {i}, differing primarily in the number of furyl groups that coordinate to the metal, with examples in which zero, one or two M-O_furyl bonds are present. Preliminary investigation in two areas of catalysis are presented.     

Syntheses and characterization of new (pyrazolato)(pyrazole) rutheniums with κ-polypyrazolylborates: Halogeno-anion binding through the tris(pyrazole) moiety

(Polypyrazolylborato)(benzonitrile) ruthenium(II) complexes [RuCl{BR(pz)₃}(PhCN)₂] (R = pz, H; pz = pyrazol-1-yl), prepared from trans-[RuCl₂(PhCN)₄] and K[BR(pz)₃], were allowed to react with potassium 3,5-dimethyl-substituted polypyrazolylborate salt K[BH(3,5-Me₂pz)₃], and gave (pyrazolato)(pyrazole) species of [Ru{BR(pz)₃}(3,5-Me₂pz)(3,5-Me₂pzH)₂] {R = pz (1), H (2)}, respectively. Upon protonation with HBF₄ (Et₂O), the species 1 was converted to a fairly stable tris(pyrazole) derivative [Ru{B(pz)₄}(3,5-Me₂pzH)₃]BF₄ (3), which worked as a novel halogeno-anion receptor. Moreover, the complex [RuCl₂(PhCN)₄] was treated with K[BH(3,5-Me₂-4-Brpz)₃] in the presence of 3,5-dimethyl-4-bromopyrazole, 3,5-Me₂-4-BrpzH, to afford [Ru{BH(3,5-Me₂-4-Brpz)₃}(3,5-Me₂-4-Brpz)(3,5-Me₂-4-BrpzH)₂] and [Ru{BH(3,5-Me₂-4-Brpz)₃}(3,5-Me₂-4-Brpz)(3,5-Me₂-4-BrpzH)(PhCN)]. Single-crystal X-ray structural analyses were carried out for 1, 3 · CHCl₃, [Ru{B(pz)₄}(3,5-Me₂pzH)₂(OH₂)]O₃SC₆H₄CH₃ · CH₃OH, and [RuCl{B(pz)₄}(3,5-Me₂pzH)₂] · CHCl₃.     

Diiron and diruthenium aminocarbyne complexes containing pseudohalides: stereochemistry and reactivity

Acetonitrile is easily displaced from [Fe₂{μ-CN(Me)(R)}(μ-CO)(CO)(MeCN)(Cp)₂][SO₃CF₃] (R = 2,6-Me₂C₆H₃ (Xyl) (1a); Me (1b)) upon stirring in THF at room temperature in the presence of [NBu₄][SCN]. The resulting complexes trans-[Fe₂{μ-CN(Me)(R)}(μ-CO)(CO)(NCS)(Cp)₂] (R = Xyl (trans-2a); Me (trans-2b)) are completely isomerised to cis-[Fe₂{μ-CN(Me)(R)}(μ-CO)(CO)(NCS)(Cp)₂] (R = Xyl (cis-2a); Me (cis-2b)) when heated at reflux temperature. Similarly, the complexes cis-[M₂{μ-CN(Me)(R)}(μ-CO)(CO)(NCO)(Cp)₂] (M = Fe, R = Me (4a); M = Ru, R = Xyl (4b); M = Ru, R = Me (4c)) and cis-[M₂{μ-CN(Me)(R)}(μ-CO)(CO)(N₃)(Cp)₂] (M = Fe, R = Xyl (5a); M = Fe, R = Me (5b); M = Ru, R = Xyl (5c)) can be obtained by heating at reflux temperature a THF solution of [M₂{μ-CN(Me)(R)}(μ-CO)(CO)(MeCN)(Cp)₂][SO₃CF₃] (M = Fe, R = Xyl (1a); M = Fe, Me (1b); M = Ru, R = Xyl (1c); M = Ru, R = Me (1d)) in the presence of NaNCO and NaN₃, respectively. The reactions of 5 with MeO₂CCCCO₂Me, HCCCO₂Me and (NC)(H)CC(H)(CN) afford the triazolato complexes [M₂{μ-CN(Me)(R)}(μ-CO)(CO){N₃C₂(CO₂Me)₂}(Cp)₂] (M = Fe, R = Xyl (6a); M = Fe, R = Me (6b); M = Ru, R = Xyl (6c)), [M₂{μ-CN(Me)(R)}(μ- CO)(CO){N₃C₂(H)(CO₂Me)}(Cp)₂] (M = Fe, R = Me (7a); M = Ru, R = Xyl (7b)) and [Fe₂{μ-CN(Me)(Xyl)}(μ-CO)(CO){N₃C₂(H)(CN)}(Cp)₂] (8), respectively. The asymmetrically substituted triazolato complexes 7-8 are obtained as mixtures of N(1) and N(2) bonded isomers, whereas 6 exists only in the N(2) form. Methylation of 6-8 results in the formation of the triazole complexes [Fe₂{μ-CN(Me)(Xyl)}(μ-CO)(CO){N₃(Me)C₂(CO₂Me)₂}(Cp)₂][CF₃SO₃] (9), [M₂{μ-CN(Me)(R)}(μ-CO)(CO){N₃(Me)C₂(H)(CO₂Me)}(Cp)₂][CF₃SO₃] (M = Fe, R = Me (10a); M = Ru, R = Xyl (10b)) and [Fe₂{μ-CN(Me)(Xyl)}(μ-CO)(CO){N₃(Me)C₂(H)(CN)}(Cp)₂][CF₃SO₃], 11. The crystal structures of trans-2b, 4b · CH₂Cl₂, 5a, 6b · 0.5CH₂Cl₂ and 8 · CH₂Cl₂ have been determined.     

Syntheses and characterization of titanium malonato and amino acid complexes: [Ti(cp)2(OOCCH2NMe2)] - The first structurally characterized α-amino acid titanium(III) complex

The reaction of [Ti(cp^∗)₂(BTMSA)] (1) (cp^∗ = η⁵-C₅Me₅, BTMSA = bis(trimethylsilyl)acetylene) with malonic acids ((HOOC)₂CR₂, R = H, Me) and N,N-dimethylglycine resulted in the formation of titanium(IV) dicarboxylato complexes [Ti(cp^∗)₂{(OOC)₂CR₂}] (R = H, 2; R = Me, 3) and an α-amino acid titanium(III) complex [Ti(cp^∗)₂(OOCCH₂NMe₂)] (4). The identities of complexes 2-4 were confirmed by microanalysis, ¹H and ¹³C NMR spectroscopy (2, 3), ESI-MS and CID experiments (2, 3) as well as by ESR and magnetic measurements (μ_eff = 1.81, 298 K) for 4. Single X-ray diffraction analyses of 2 and 4 exhibited monomolecular complexes in which the titanium atom is distorted tetrahedrally coordinated by two η⁵-C₅Me₅ rings and by the chelating bound malonato-κ²O,O′ (2) and N,N-dimethylglycinato-κ²O,O′ ligand (4).     

Synthesis and reactivity with amines of new diiron alkynyl methoxy carbene complexes

The new diiron alkynyl methoxy carbene complexes [Fe₂{μ-CN(Me)(R)}(μ-CO)(CO){C(OMe)CCR′}(Cp)₂]⁺ (R = 2,6-Me₂C₆H₃ (Xyl), R′ = Tol, 3a; R = Xyl, R′ = Ph, 3b; R = Xyl, R′=Buⁿ, 3c; R = Xyl, R′=SiMe₃, 3d; R = Me, R′ = Tol, 3e; R = Me, R′ = Ph, 3f) are obtained in two steps by addition of R′CCLi (R′ = Tol, Ph, Buⁿ, SiMe₃) to the carbonyl aminocarbyne complexes [Fe₂{μ-CN(Me)(R)}(μ-CO)(CO)₂(Cp)₂]⁺ (R = Xyl, 1a; Me, 1b), followed by methylation of the resulting alkynyl acyl compounds [Fe₂{μ-CN(Me)(R)}(μ-CO)(CO){C(O)CCR′}(Cp)₂] (R = Xyl, R′ = Tol, 2a; R = Xyl, R′ = Ph, 2b; R = Xyl, R′ = Buⁿ, 2c; R = Xyl, R′ = SiMe₃, 2d; R = Me, R′ = Tol, 2e; R = Me, R′ = Ph, 2f). Complexes 3 react with secondary amines (i.e., Me₂NH, C₅H₁₀NH) to give the 4-amino-1-metalla-1,3-dienes [Fe₂{μ-CN(Me)(R)}(μ-CO)(CO){C(OMe)CHC(R′)(NMe₂)}(Cp)₂]⁺ (R = Xyl, R′ = Tol, 4a; R = Xyl, R′ = Ph, 4b; R = Me, R′ = Ph, 4c) and [Fe₂{μ-CN(Me)(Xyl)}(μ-CO)(CO){C(OMe)CHC(Tol)(NC₅H₁₀)}(Cp)₂]⁺, 5. The addition occurs stereo-selectively affording only the E-configured products. Analogously, addition of primary amines R′NH₂ (R′ = Ph, Et, Prⁱ) affords the 4-(NH-amino)-1-metalla-1,3-diene complexes [Fe₂{μ-CN(Me)(Xyl)}(μ-CO)(CO){C(OMe)CHC(R)(NHR′)}(Cp)₂]⁺ (R = Ph, 6a; Et, 6b; Prⁱ, 6c). In the case of 6a, only the E isomer is formed, whereas a mixture of the E and Z isomers is present in the case of 6b,c, with prevalence of the latter. Moreover, the two isomeric forms exist under dynamic equilibrium conditions, as shown by VT NMR studies. Complexes 6 are deprotonated by strong bases (e.g., NaH) resulting in the formation of the neutral vinyl imine complexes [Fe₂{μ-CN(Me)(Xyl)}(μ-CO)(CO){C(OMe)CHC(NR)(Tol)}(Cp)₂] (R = Ph, 7a; Et, 7b; Prⁱ, 7c); the reaction can be reverted by addition of strong acids. X-ray crystal structures have been determined for 3a[CF₃SO₃] · Et₂O, 4c[CF₃SO₃], 6a[BF₄] · CH₂Cl₂, 6c[CF₃SO₃] · 0.5Et₂O and 7a · CH₂Cl₂.     

Preparation and characterization of macrocyclic dinickel complexes coligated by monoalkyl- and dialkylcarbamates

The dinuclear nickel(II) complex [Ni₂L(Cl)]⁺ (1), where (L)²⁻ represents a 24-membered binucleating hexamine-dithiophenolate ligand, reacts readily with primary and secondary amines RR′NH in the presence of CO₂ (1 bar) to give dinuclear monoalkyl- and dialkylcarbamate complexes [Ni₂L(O₂CNRR′)]⁺ (R = H, R′ = CH₂Ph (2), R = H, R′ = n-Bu (3), R = H, R′ = n-Oct (4), R = H, R′ = CH₂CH₂OH (5), R = R′ = Et (6), and R = R′ = CH₂CH₂OH (7)). Complexes 2-7 can also be prepared by the reaction of 1 with CO₂(air)/amine. The carbamate complexes are hydrolyzed in methanolic solution to give the known alkylcarbonate complex [Ni₂L(O₂COMe)]⁺ (8). These conversions are less rapid than the transesterification reactions of 8, due to a less electron-demanding carboxyl C(carbamate) atom. All new complexes were either isolated as perchlorate or tetraphenylborate salts and fully characterized by elemental analysis, UV/Vis, and IR spectroscopy. The structures of 2[BPh₄] and 7[BPh₄] have also been determined by X-ray crystallography. They confirm the presence of μ_1,3-bridging alkylcarbamate units in the products.     

Calix[4]arene supported group 5 imido complexes

The reaction of imidoyl chlorides [V(NR)Cl₃] (R = Ph 1, Tol 2, tBu 3) and calix[4]arene methyl ether H₃Mecalix unexpectedly leads to the formation of the structurally characterized vanadium (IV) complex [VCl(Mecalix)] (4). Calix[4]arene methyl ether stabilized imido complexes of the type [V(NR)(Mecalix)] (R = Ph 7, Tol 8, tBu 9) were afforded from the reaction of [V(NR)Cl₃] (R = Ph 1, Tol 2, tBu 3) and the tris(lithium) or tris(sodium) salt of the calix[4]arene ether. The lithium salt [{Li₃(Mecalix)}₂] (5) is a dimer in the solid state, in which two monomeric trianions are bridged by lithium cations. Imido complexes [M(NR)(Mecalix)] (M = Nb: R = tBu, 12, R = Tol 13, R = Mes 14, R = Dipp 15; M = Ta: R = tBu 16, R = Tol 17) (Tol = 4-C₆H₄Me, Mes = 2,6-C₆H₃Me₂; Dipp = 2,6-C₆H₃iPr₂) have been prepared from structurally characterized [NbCl₂(Mecalix)] (10) and previously known [TaCl₂(Mecalix)] (11) via reaction with two equivalents of the appropriately metallated (Li, K) primary amine. The molecular structures of 13 and 15 confirm the mononuclear nature of these complexes.     

Synthesis and characterization of CpMCl(PR3)(S or W-η-butadienesulfonyl) compounds of rhodium and iridium

A metathesis reaction of [Cp^∗MCl₂(PR₃)] [M = Rh, R = Ph (1), Me (3); M = Ir, R = Ph (2), Me (4)] takes place in the presence of potassium butadienesulfinate (SO₂CHCHCHCH₂)K (9) to afford the mononuclear compounds [Cp^∗M(Cl)(PR₃)(η¹-SO₂CHCHCHCH₂)] [M = Rh, R = Ph (11S), (11W); M = Rh, R = Me (13S), (13W)] and [M = Ir, R = Ph (12S); M = Ir, R = Me (14S), (14W)] under different reaction conditions. The addition of PR₃ (R = Ph, Me) to Cp^∗Ir(Cl)[(1,2,5-η)-SO₂CHCHCHCH₂] (7) affords the corresponding iridium isomers 12S, 12W and 14S, in a non-selective reaction, along with the corresponding dichloride compounds 2 or 4. The ¹H and ¹³C{¹H} NMR data are consistent with the butadienesulfonyl ligands coordinated exclusively through the sulfur atom, and they show the presence of two isomers, described as the S and W conformers, which can be isolated separately. There is clear evidence that these isomers correspond to the kinetic and thermodynamic derivatives, respectively.     

Synthesis and characterization of ether-derivatized aminophosphines and their application in C-C coupling reactions

Four new bis(phosphino)amine ligands (Ph₂P)₂N-C₆H₃-R, where R = 3,5-OMe (1), 2,5-OMe (2), 2,4-OMe (3) or 3,4-OMe (4), were prepared via aminolysis of the corresponding dimethoxyanilines with 2 equiv. of diphenylphosphine chloride in the presence of triethyl amine. Oxidation of these ligands with aqueous H₂O₂, elemental S₈ or Se powder afforded the corresponding chalcogen oxides 1a-4a, sulfides 1b-4b and selenides 1c-4c in good yields. Reaction of 1-4 with [MCl₂(cod)] (M = Pt, Pd; cod = cycloocta-1,5-diene) in equimolar ratios afforded cis-[MCl₂{(Ph₂P)₂N-C₆H₃-R}] (M = Pt; R = 3,5-OMe 1d, R = 2,5-OMe 2d, R = 2,4-OMe 3d, and R = 3,4-OMe 4d. M = Pd; R = 3,5-OMe 1e, R = 2,5-OMe 2e, R = 2,4-OMe 3e, and R = 3,4-OMe 4e). Similarly, reaction of [Cu(CH₃CN)₄]PF₆ with the 1-4 in 1:2 ratio gave [Cu{(Ph₂P)₂N-C₆H₃-R}₂]PF₆ (R = 3,5-OMe 1f, 2,5-OMe 2f, 2,4-OMe 3f and 3,4-OMe 4f). All new compounds were fully characterized by spectroscopy and elemental analysis and the molecular structures of seven representative compounds were determined by single-crystal X-ray crystallography. In addition, the palladium complexes were investigated as pre-catalysts in C-C coupling reactions.     

Phosphane- and phosphite-silver(I) phenolates: Synthesis, characterization and their use as CVD precursors

The silver(I) salts [AgOR] (3a, R = C₉H₆N; 3b, R = C₆H₄-2-CHO, 3c, R = C₆H₄-2-Cl; 3d, R = C₆H₄-2-CN; 3e, R = C₆H₄-2-NO₂) are accessible by the stoichiometric reaction of [AgNO₃] (1) with HOR (2a, R = C₉H₆N; 2b, R = C₆H₄-2-CHO; 2c, R = C₆H₄-2-Cl; 2d, R = C₆H₄-2-CN; 2e, R = C₆H₄-2-NO₂) in presence of NEt₃. Treatment of 3a-3e with PⁿBu₃ (4), P(OMe)₃ (5a) or P(OCH₂CF₃)₃ (5b) in the ratios of 1:1 and 1:2, respectively, produced complexes [L_mAgOR] (L = PⁿBu₃, m = 1: 6a, R = C₉H₆N; 6b, R = C₆H₄-2-CHO; 6c, R = C₆H₄-2-Cl; 6d, R = C₆H₄-2-CN; 6e, R = C₆H₄-2-NO₂. m = 2: 7a, R = C₉H₄; 7b, R = C₆H₄-2-CHO; 7c, R = C₆H₄-2-Cl; 7d, R = C₆H₄-2-CN; 7e, R = C₆H₄-2-NO₂. L = P(OMe)₃, m = 1: 8a, R = C₆H₄-2-CHO; 8b, R = C₆H₄-2-NO₂. m = 2: 9, R = C₆H₄-2-NO₂. L = P(OCH₂CF₃)₃, m = 1: 10, R = C₆H₄-2-NO₂). Based on TGA, temperature-programmed and in situ molecular beam mass spectrometry metal-organic 7e was applied as CVD precursor in the deposition of silver onto glass substrates. The resulting silver films were characterized by XRD. The SEM image of a film grown from 7e at 350 °C showed a homogeneous surface with grain sizes of 40 nm. The molecular structures of 8b and 10 in the solid state were determined. They are isostructural and are cubane-like structured. Low-temperature ³¹P{¹H} NMR studies showed that the title complexes are dynamic in solution and exchange at room temperature their ligands.     

New palladacyclic complexes with pyridylphosphine ligands: crystal structures of [Pd(Azb)(Ph2POCH2Py-P,N)][PF6] and [Pd(Phpy)(Ph2PNHPy-P,N)][PF6]

The synthesis of palladacyclic derivatives with the hybrid pyridylphosphine ligands Py(CH₂)OPPh₂ (a) and PyNHPPh₂ (b) in a neutral P,N-chelating coordination mode has been achieved. Treatment of selected chloride-bridged cyclometallated precursors [Pd(C^∧N)(μ-Cl)]₂ [C^∧N = 2-pyridinin-phenyl Phpy, I-compounds; 7,8-benzoquinolyl Bzq, II-compounds; phenylazophenyl Azb, III-compounds or 2-(2-oxazolinyl)phenyl Phox, IV-compounds] with a or b in the presence of stoichiometric KPF₆ gave the mononuclear derivatives Ia-IVa and Ib-IVb. The crystal structures of compounds [Pd(Azb)(Ph₂POCH₂Py-P,N)][PF₆] (IIIa) and [Pd(Phpy)(Ph₂PNHPy-P,N)][PF₆] (Ib) have been determined. The new palladacyclopentadiene precursor [Pd{C₄COOMe₄}(CH₃CN)₂] (V) has been prepared starting from the polymeric complex [Pd{C₄COOMe₄}]_n. Its usefulness in the preparation of new derivatives has been tested by means of the straightforward reaction with ligands (a) or (b) to give mononuclear compounds [Pd{C₄(COOMe)₄}(Ph₂POCH₂Py-P,N)] (Va) and [Pd{C₄(COOMe)₄}(Ph₂PNHPy-P,N)] (Vb). The reactions of hydroxo-bridged precursors [Pd(C^∧N)(μ-OH)]₂ or [Pd₂{C₄(COOMe)₄}₂ (μ-OH)₂][NBu₄]₂ with PyNHPPh₂ afforded mononuclear complexes Ic-Vc in which a less common anionic P,N-binding mode is forced as a result of ligand deprotonation. The new complexes were characterised by partial elemental analyses and spectroscopic methods (IR, FAB, ¹H and ³¹P{¹H} NMR).     

An unsaturated half-sandwich ruthenium(II) complex containing a dithioimidodiphosphinate ligand

Treatment of [Cp*RuCl₂]_x (Cp* = η⁵-C₅Me₅) with K[N(Ph₂PS)₂] afforded [Cp*Ru{N(Ph₂PS)₂}Cl] (1). Reduction of 1 with Li[BEt₃H] gave the 16-electron half-sandwich Ru(II) complex [Cp*Ru{N(Ph₂PS)₂}] (2). Complexes 1 and 2 have been characterized by X-ray crystallography. The Ru-Cp*(centroid) and average Ru-S distances in 1 are 1.827 and 2.3833(5) Å, respectively. The corresponding bond distances in 2 are 1.739 and 2.379(1) Å. Treatment of 2 with 2-electron ligands L afforded the adducts [Cp*Ru{N(Ph₂PS)₂}L] (L = CO (3), 2,6-Me₂C₆H₄NC (4), MeCO₂CCCO₂Me (5)). Oxidation of 2 with tetramethylthiuram disulfide gave the Ru(IV) complex [Cp*Ru{S₂CNMe₂}₂][N(Ph₂PS)₂] (6). The Ru-Cp*(centroid) and average Ru-S distances in 6 are 1.897 and 2.387(1) Å, respectively.     

Lewis-base copper(I) formates: Synthesis, reaction chemistry, structural characterization and their use as spin-coating precursors for copper deposition

Consecutive synthesis methodologies for the preparation of a series of copper(I) formates [L_mCuO₂CH] (L = ⁿBu₃P: 4a, m = 1; 4b, m = 2; 5, L = [Ti](CCSiMe₃)₂, m = 1, [Ti] = (η⁵-C₅H₄SiMe₃)₂Ti) and [L_mCuO₂CH·HO₂CR] (L = ⁿBu₃P: 7a, m = 1, R = H; 7b, m = 2, R = H; 7c, m = 2, R = Me; 7d, m = 2, R = CF₃; 7e, m = 2, R = Ph. L = (^cC₆H₁₁)₃P, R = H: 8a, m = 2; 8b, m = 3. L = (CF₃CH₂O)₃P, R = H: 9a, m = 2; 9b, m = 3. L = (CH₃CH₂O)₃P, R = H: 10a, m = 2; 10b, m = 3. L = [Ti](CCSiMe₃)₂; m = 1: 11a, R = H; 11b, R = Ph) is reported using [CuO₂CH] (1) and L (2a, L = ⁿBu₃P; 2b, L (^cC₆H₁₁)₃P; 2c, L = (CF₃CH₂O)₃P; 2d, L = (CH₃CH₂O)₃P; 3, L = [Ti](CCSiMe₃)₂) as key starting materials. Addition of formic acid (6a) or carboxylic acid HO₂CR (6b, R = Me; 6c, R = CF₃; 6d, R = Ph) to the afore itemized copper(I) formates 4 and 5 gave metal-organic or organometallic 7-11. The molecular structures of 8a and 11a in the solid state are reported showing a threefold coordinated copper(I) ion, setup by either two coordinatively-bonded phosphorus atoms and one formate oxygen atom (8a) or two π-bonded alkyne ligands and one oxygen atom (11a). A formic acid molecule is additionally hydrogen-bonded to the CuO₂CH moiety. The use of 7b as suitable precursor for the deposition of copper onto TiN-coated oxidized silicon wafers by the spin-coating process below 300 °C is described. Complex 7b offers an appropriate transformation behavior into metal phase by an elimination-decarboxylation mechanism. The morphology of the copper films strongly depends on the annealing conditions. A closed grain network densified by a post-treatment is obtained (8 °C min⁻¹, N₂/H₂ carrier gas). Hydrogen post-anneal to 420 °C after film deposition gave a copper film showing resistivities from 2.5 to 3.7 μΩ cm. This precursor was also used for gap-filling processes.     

Synthesis, spectroscopic properties, X-ray single crystal analysis and antimicrobial activities of organotin(IV) 4-(4-methoxyphenyl)piperazine-1-carbodithioates

A series of mononuclear organotin(IV) complexes of the types, R₃SnL {R = C₄H₉ (1), C₆H₁₁ (2), CH₃ (3) and C₆H₅ (4)}, R₂SnClL {R = C₄H₉ (5), C₂H₅ (7) and CH₃ (9)} and R₂SnL₂ {R = C₄H₉ (6), C₂H₅ (8) and CH₃ (10)}, have been synthesized, where L = 4-(4-methoxyphenyl)piperazine-1-carbodithioate. The ligand-salt and the complexes have been characterized by Raman, FT-IR and multinuclear NMR (¹H, ¹³C and ¹¹⁹Sn) spectroscopy and elemental microanalysis (CHNS). The spectroscopic data substantiate coordination of the ligands to the organotin moieties. The structures of complexes 4 and 6 have been determined by single-crystal X-ray diffraction and illustrate the asymmetric bidentate bonding of the ligand. The packing diagrams indicate O···H and π···H intermolecular interactions in complex 4 and intermolecular S₂C···H interactions in complex 6, resulting in layer structures for both complexes. A subsequent antimicrobial study indicates that the compounds are active biologically and may well be the basis for a new class of fungicides.     

Synthesis, reactivities and catalytic carbonylation of rhodium(I) carbonyl complexes containing isomeric acetylpyridine ligands

[Rh(CO)₂Cl]₂ reacts with two mole equivalent of 2-acetylpyridine (a), 3-acetylpyridine (b) and 4-acetylpyridine (c) to afford chelate [Rh(CO)Cl(η²-N∩O)] (1a) and non-chelate [Rh(CO)₂Cl(η¹-N∼O)] (1b, 1c) complexes, where, N∩O = a, N∼O = b, c. Oxidative addition (OA) of 1a-1c with CH₃I and C₂H₅I yields penta coordinate rhodium(III) complexes, [Rh(COR)ClI(η²-N∩O)] {R = -CH₃ (2a); -C₂H₅ (3a)} and [Rh(COR)(CO)ClI(η¹-N∼O)] {R = -CH₃ (2b, 2c); -C₂H₅ (3b, 3c)}. Kinetic study for the reaction of 1a-1c with CH₃I indicates a pseudo-first order reaction. The catalytic activity of 1a-1c for the carbonylation of methanol to acetic acid and its ester was evaluated at different initial CO pressures 5, 10 and 20 bar at ∼25 °C and higher turn over numbers (TON = 1581-1654) were obtained compared to commercial Monsanto’s species [Rh(CO)₂I₂]⁻ (TON = 1000) under the reaction conditions: temperature = 130 ± 1 °C, pressure = 15-32 bar, rpm = 450, time = 1 h and catalyst: substrate = 1: 1900.     

Stereosensitive formation and interconversion of sulfur-bridged cobalt(III)-mercury(II) polynuclear complexes with d- and/or l-penicillaminates

The reaction of trans(N)-[Co(d-pen)₂]⁻ (pen = penicillaminate) with HgCl₂ or HgBr₂ in the molar ratios of 1:1 gave the sulfur-bridged heterodinuclear complex, [HgX(OH₂){Co(d-pen)₂}] (X = Cl (1a) or Br (1b)). A similar reaction in the ratio of 2:1 produced the trinuclear complex, [Hg{Co(d-pen)₂}₂] (1c). The enantiomers of 1a and 1c, [HgCl(OH₂){Co(l-pen)₂}] (1a′) and [Hg{Co(l-pen)₂}₂] (1c′), were also obtained by using trans(N)-[Co(l-pen)₂]⁻ instead of trans(N)-[Co(d-pen)₂]⁻. Further, the reaction of cis · cis · cis-[Co(d-pen)(l-pen)]⁻ with HgCl₂ in the molar ratio of 1:1 resulted in the formation of [HgCl(OH₂){Co(d-pen)(l-pen)}] (2a). During the formations of the above six complexes, 1a, 1b, 1c, 1a′, 1c′, and 2a, the octahedral Co(III) units retain their configurations. On the other hand, the reaction of cis · cis · cis-[Co(d-pen)(l-pen)]⁻ with HgCl₂ in the molar ratio of 2:1 gave not [Hg{Co(d-pen)(l-pen}₂] but [Hg{Co(d-pen)₂}{Co(l-pen)₂}] (2c), accompanied by the ligand-exchange on the terminal Co(III) units. The X-ray crystal structural analyses show that the central Hg(II) atom in 1c takes a considerably distorted tetrahedral geometry, whereas that in 2c is of an ideal tetrahedron. The interconversion between the complexes is also examined. The electronic absorption, CD, and NMR spectral behavior of the complexes is discussed in relation to the crystal structures of 1c and 2c.     

Synthesis and characterization of di- and tri-organotin(IV) complexes with Schiff base ligand pyruvic acid 3-hydroxy-2-naphthoyl hydrazone

A series of organotin(IV) complexes with Schiff base ligand pyruvic acid 3-hydroxy-2-naphthoyl hydrazone [R₂SnLY]₂, L = 3-HO-C₁₀H₆-2-CONHNC(CH₃)COOH, R = n-C₄H₉, Y = CH₃OH (1), R = n-C₄H₉, Y = N (2), R = PhCH₂ (3), R = Ph, Y = CH₃OH (4), R = Me, (5) and [R₃SnLY], L = 3-HO-C₁₀H₆-2-CONHNC(CH₃)COOH, R = n-C₄H₉, Y = H₂O, (6), R = Ph (7), R = Me (8) have been synthesized. These complexes have been characterized by elemental analysis, IR, ¹H and ¹¹⁹Sn NMR spectra. The crystal and molecular structure of complexes 1, 2 and 6 have been determined by X-ray single crystal diffraction. Results showed that complex 1 has a dimeric structure and the central tin atom is rendered seven-coordinate in a distorted pentagonal-bipyramid configuration. The complex 2 has a monoclinic structure and the central tin atom is rendered six-coordinate in octahedrally configuration with a planar of SnO₃N unit and two apical aryl C atoms. And the whole structure consists of molecular units connected by weak intermolecular Sn?N and O-H?N interactions. In the complex 6, the central tin atom is five-coordinate in distorted trigonal-bipyramidal geometry.     

Stereospecific interactions between dinuclear complex cations involving square-planar [Pt(II)(μ-S)2(bpy)] (bpy = 2,2′-bipyridine) frameworks derived from optically active octahedral Co(III) units with d- or l-penicillaminates

The reaction of the octahedral mononuclear complex, trans(N)-[Co(l-pen-N,O,S)₂]⁻ (pen = penicillaminate), with [PtCl₂(bpy)] (bpy = 2,2′-bipyridine) stereoselectively gave an optically active S-bridged dinuclear complex, [Pt(bpy){Co(l-pen)₂}]Cl · 3H₂O (2Cl · 3H₂O), whose structure is enantiomeric to the previously reported [Pt(bpy){Co(d-pen)₂}]Cl · 3H₂O (1Cl · 3H₂O). The mixture of equimolar amounts of 1Cl · 3H₂O and 2Cl · 3H₂O in H₂O crystallizes as [Pt(bpy){Co(d-pen)₂}]_0.5[Pt(bpy){Co(l-pen)₂}]_0.5Cl · 7H₂O (3Cl · 7H₂O), in which the enantiomeric complex cations 1 and 2 are included in the ratio of 1:1. The crystal structures of 2Cl · 3H₂O and 3Cl · 7H₂O were determined by X-ray crystallography, and compared with that of 1Cl · 3H₂O. The structural feature for 2 is essentially consistent with that for 1, except for the absolute configurations around the octahedral Co(III) center. The optically active complex cation 2 exists as a monomer, accompanied by no intermolecular interactions in the π-electronic systems of bpy moieties. In the crystals of 3Cl · 7H₂O, on the other hand, the enantiomeric complex cations, [Pt(bpy){Co(d-pen)₂}]⁺ and [Pt(bpy){Co(l-pen)₂}]⁺, are arranged alternately while overlapping the bpy planes along a axis, and the π electronic system of the bpy framework in [Pt(bpy){Co(d-pen)₂}]⁺ interacts with those in [Pt(bpy){Co(l-pen)₂}]⁺. Differences between the crystal structures of 2Cl · 3H₂O and3Cl · 7H₂O significantly reflect their diffuse reflectance spectra. In aqueous solution, each cation in both 2Cl · 3H₂O and 3Cl · 7H₂O is comparatively put on a free environment without such intermolecular interactions.