Pyridine and phosphine reactions with [CPh3][B(C6F5)4]

Trityl borate salts [4-RPyCPh₃][B(C₆F₅)₄] (R = H 1, ^tBu 2, Et 3, NMe₂4) and [R₃PCPh₃][B(C₆F₅)₄] (R = Me 5, ⁿBu 6, Ph[1] 7, p-MeC₆H₄8) are readily prepared via equimolar reaction of the appropriate pyridine or phosphine and trityl borate [CPh₃][B(C₆F₅)₄]. The analogous reactions of PⁱPr₃ affords the product [(p-ⁱPr₃P-C₆H₄)Ph₂CH][B(C₆F₅)₄] (9) while the corresponding reactions of Cy₃P and ^tBu₃P gave the cyclohexadienyl derivatives [(p-R₃PC₆H₅)CPh₂][B(C₆F₅)₄] (R = Cy 10, ^tBu 11). X-ray structures of 5 and 9 are reported.     

Organotin(IV) 4-methoxyphenylethanoates: Synthesis, spectroscopic characterization, X-ray structures and in vitro anticancer activity against human prostate cell lines (PC-3)

A series of organotin(IV) carboxylates, [Bu₂SnL₂] (1), [Et₂SnL₂] (2), [Me₂SnL₂] (3), [Bu₃SnL]_n(4), [Me₆Sn₂L₂]_n(5), [Ph₃SnL]_n(6) and [Oct₂SnL₂] (7), where L = O₂CCH₂C₆H₄OCH₃-4, have been synthesized. These complexes have been characterized by elemental analysis, FT-IR and multinuclear NMR (¹H, ¹³C and ¹¹⁹Sn). Based on spectroscopic results, the ligand appeared to coordinate to the Sn atom through COO moiety. Single crystal analysis has shown a bridging behavior of ligand in tributyl- and trimethyltin(IV) derivatives, and a chelating bidentate mode in diethyltin(IV) complex. Bioassay results have shown that these compounds have good antibacterial, antifungal and antitumor activity. The activity against prostate cancer cell lines (PC-3) decreased in the order 1 > 5 > 2 > 3 > 7.     

Acid-base behavior of a simple metal bis(dithiolate) system: Synthesis, crystal structure and spectroscopy of [Bu4N]2[M(ppdt)2] (M = Ni, Pt; ppdt = pyrido[2,3-b]pyrazine-2,3-dithiolate)

The syntheses, crystal structures and properties of compounds [Bu₄N]₂[Ni(ppdt)₂] (1) and [Bu₄N]₂[Pt(ppdt)₂] (2) (ppdt = pyrido[2,3-b]pyrazine-2,3-dithiolate) have been described. Compound 1 crystallizes in P2₁/c space group (monoclinic system), whereas compound 2 crystallizes in C2/c space group (monoclinic system). The crystal structures of both compounds 1 and 2 have been characterized by C-H?S and C-H?N hydrogen bonding interactions between cation and anions resulting in three-dimensional supramolecular networks in the crystals of 1 and 2, respectively. The acid-base behavior of the ground states of both [Bu₄N]₂[Ni(ppdt)₂] (1) and [Bu₄N]₂[Pt(ppdt)₂] (2) and also the excited state of compound [Bu₄N]₂[Pt(ppdt)₂] (2) in solutions has been studied. The pH dependent changes in the charge transfer absorption and emission spectra are attributed to the protonation on an imine nitrogen of the ppdt ligand. The ground-state basicity constants of the two complexes 1 and 2 have been determined from spectrophotometric analysis by titrating with an weak acid, yielding pK_b1 = 8.0 for complex [Bu₄N]₂[Ni(ppdt)₂] (1) and pK_b1 = 7.8 for complex [Bu₄N]₂[Pt(ppdt)₂] (2). The excited-state basicity constant pK_b1^* for complex [Bu₄N]₂[Pt(ppdt)₂] (2) has been determined by a thermodynamic equation using a Förster analysis yielding the value of 1.8. The complex 2 is electrochemically irreversible with an oxidation potential of E_1/2 = +0.41 V versus Ag/AgCl in methanol.     

Five- and six-coordinate hydridorhodium(III) complexes containing metalated Schiff-bases as ligands

The reactions of either [RhCl(C₈H₁₄)₂]₂ (2) or [RhCl(C₂H₄)₂]₂ (3) with Schiff-bases 1a-d derived from 2-aminopyridine afford, in the presence of four equivalents of PiPr₃, the octahedral chloro(hydrido)rhodium(III) complexes [{(C₅H₄N)NC(C₆H₄R)}RhHCl(PiPr₃)₂] (4a-d) in which the metalated Schiff-base behaves as a chelating ligand. Treatment of 4a (RH) with NaI and CF₃SO₃Tl produce the corresponding derivatives [{(C₅H₄N)NC(C₆H₅)}RhHX(PiPr₃)₂] (5, 6) by salt metathesis. The triflato compound 6 reacts with nBu₄NF · xH₂O to give [{(C₅H₄N)NC(C₆H₅)}RhHF(PiPr₃)₂] (7). While attempts to eliminate HCl from 4a failed, the reaction of 4a with AgPF₆ generates the five-coordinate cationic complex [{(C₅H₄N)NC(C₆H₅)}RhH(PiPr₃)₂]PF₆ (8) which adds one equivalent of acetonitrile to give [{(C₅H₄N)NC(C₆H₅)}RhH(NCCH₃)(PiPr₃)₂]PF₆ (9). Treatment of 4a with either nBu₂Mg or LiAlH₄ affords the dihydridorhodium(III) compound [{(C₅H₄N)NC(C₆H₅)}RhH₂(PiPr₃)₂] (10) being also accessible from 8 and nBu₂Mg.     

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.     

Synthesis and reactivity of osmium (VI) nitrido complexes containing pyridine-carboxylato ligands

A series of osmium(VI) nitrido complexes containing pyridine-carboxylato ligands Os^VI(N)(L)₂X (L = pyridine-2carboxylate (1), 2-quinaldinate (2) and X = Cl (a), Br (1b and 2c) or CH₃O (2b)) and [Os^VI(N)(L)X₃]⁻ (L = pyridine-2,6-dicarboxylate (3) and X = Cl (a) or Br (b)) have been synthesised. Complexes 1 and 2 are electrophilic and react readily with various nucleophiles such as phosphine, sulfide and azide. Reaction of Os^VI(N)(L)₂X (1 and 2) with triphenylphosphine produces the osmium(IV) phosphiniminato complexes Os^VI(NPPh₃)(L)₂X (4 and 5). The kinetics of nitrogen atom transfer from the complexes Os^VI(N)(L)₂Br (2c) (L = 2-quinaldinate) with triphenylphosphine have been studied in CH₃CN at 25.0 °C by stopped-flow spectrophotometric method. The following rate law is obtained: −d[Os(VI)]/dt = k₂[Os(VI)][PPh₃]. Os^VI(N)(L)₂Cl (L = 2-quinaldinate) (2a) reacts also with [PPN](N₃) to give an osmium(III) dichloro complex, trans-[PPN][Os^III(L)₂Cl₂] (6). Reaction of Os^VI(N)(L)₂Cl (L = 2-quinaldinate) (2a) with lithium sulfide produces an osmium(II) thionitrosyl complex Os^II(NS)(L)₂Cl (7). These complexes have been structurally characterised by X-ray crystallography.     

Half-sandwich ruthenium thiocarbonate complexes: Structures of CpRu(PPh3)2SCO2Bu, CpRu(dppe)SCO2Bu and CpRu(PPh3)(CO)SCO2Bu

Thiocarbonate ruthenium complexes of the form CpRu(L)(L′)SCO₂R (L = L′ = PPh₃ (1), 1/2 dppe (2), L = PPh₃, L′ = CO (3); R = Et (a), Buⁿ (b), C₆H₅ (c), 4-C₆H₄NO₂ (d)) have been synthesized by the reaction of the corresponding sulfhydryl complexes, CpRu(L)(L′)SH, with chloroformates, ROCOCl, at low temperature. The bis(triphenylphosphine) complexes 1 can be converted to 3 under CO atmosphere. The crystal structures of CpRu(PPh₃)₂SCO₂Buⁿ (1b), CpRu(dppe)SCO₂Buⁿ (2b), and CpRu(PPh₃)(CO)SCO₂Buⁿ (3b) are reported.     

Synthesis, isolation and spectroscopic characterization of Dawson polyoxotungstate-supported, organometallic complex, [{(C6H6)Ru}P2W15V3O62]: The two positional isomers

The Dawson polyoxotungstate (POM)-based, organometallic ruthenium(II) complex, [{(C₆H₆)Ru}P₂W₁₅V₃O₆₂]⁷⁻, was synthesized as two materials, i.e. 1 · 2Bu₄NCl and 1 · 1Bu₄NCl (1 = (Bu₄N)₇[{(C₆H₆)Ru}P₂W₁₅V₃O₆₂]), which contained two positional isomers a and b as major or minor species. In isomer a with the overall C_s symmetry, the (C₆H₆)Ru²⁺ group was supported on one vanadium(V) octahedral site (two V-O-V bridging oxygens and one OV terminal oxygen) of the three edge-shared vanadium(V) octahedra (V₃ site, B-site) in the Dawson POM-support [1,2,3-P₂W₁₅V₃O₆₂]⁹⁻, whereas in the other isomer b with the overall C_3v symmetry, the (C₆H₆)Ru²⁺ group was supported on the center of the V₃ site in the Dawson POM-support. Material 1 · 2Bu₄NCl was prepared by a stoichiometric reaction in CH₂Cl₂ at ambient temperature of the Dawson POM-support (Bu₄N)₉[1,2,3-P₂W₁₅V₃O₆₂] with the precursor [(C₆H₆)RuCl₂]₂, whereas material 1 · 1Bu₄NCl was prepared by a stoichiometric reaction in CH₃CN under refluxing conditions. The temperature-varied ³¹P NMR spectra revealed that b was thermodynamically more stable thana.     

Aryldiazenido derivatives: A new entry to the functionalization of Keggin polyoxometalates

A series of aryldiazenido polyoxomolybdates of the type (nBu₄N)₂[Mo₅O₁₃(OMe)₄(NNAr){Na(MeOH)}] (Ar = C₆F₅, 1; Ar = O₂N-o-C₆H₄, 2; Ar = O₂N-m-C₆H₄, 3; Ar = O₂N-p-C₆H₄, 4a; Ar = (O₂N)₂-o,p-C₆H₃, 5) have been obtained by controlled degradation of the parent compounds (nBu₄N)₃[Mo₆O₁₈(NNAr)] with NaOH in methanol. They have been characterized by elemental analysis and UV-Vis and IR spectroscopy. In addition, 4a has been characterized by ⁹⁵Mo NMR spectroscopy and the crystal structure of (nBu₄N)₂[Mo₅O₁₃(OMe)₄(NNC₆H₄-p-NO₂){Na(H₂O))]·H₂O (4b) has been determined by X-ray diffraction. The molecular structure of the anion of 4b features a lacunary Lindqvist-type anion [Mo₅O₁₃(OMe)₄(NNC₆H₄-p-NO₂)]³⁻ interacting with a sodium cation through the four terminal axial oxygen atoms. The 1:1 sodium complexes react with BaCl₂ and BiCl₃ to yield 2:1 complexes which have been isolated as (nBu₄N)₄[Ba{Mo₅O₁₃(OMe)₄(NNAr)}₂] (Ar = C₆F₅, 6; Ar = O₂N-p-C₆H₄, 7) and (nBu₄N)₃[Bi{Mo₅O₁₃(OMe)₄(NNAr)}₂] (Ar = C₆F₅, 8; Ar = O₂N-p-C₆H₄, 9). X-ray crystallography analysis of 9·Me₂CO has shown that the tetradentate [Mo₅O₁₃(OMe)₄(N₂C₆H₄-p-NO₂)]³⁻ anions provide a square-antiprismatic environment for Bi. In contrast, IR spectroscopy provides evidence for a square-prismatic environment of Ba in 6 and 7. In acetonitrile-methanol mixed solvent, [Mo₅O₁₃(OMe)₄(NNAr)]³⁻ and [PW₁₁O₃₉]⁷⁻, generated in situ by alkaline degradation of their respective parents, [Mo₆O₁₈(NNAr)]³⁻ and [PW₁₂O₄₀]³⁻, react together to give the Keggin-type diazenido compounds (nBu₄N)₄[PW₁₁O₃₉(MoNNAr)] (Ar = O₂N-o-C₆H₄, 10; Ar = O₂N-m-C₆H₄, 11; Ar = O₂N-p-C₆H₄, 12), which have been characterized by ³¹P and ¹⁸³W NMR spectroscopy.     

Two new 3D (3,8)-connected metal-organic frameworks based on zinc-triazole secondary building units and benzenetricarboxylate linkers

Two new zinc-triazole-carboxylate frameworks constructed from secondary building units (SBUs), [Zn₅(trz)₄(btc)₂(DMF)₂(H₂O)₂]·2H₂O·DMF (1) and [Zn₄(trz)₃(btc)₂(CH₃CN)(H₂O)]·5H₂O·(Bu₄N) (2), [Htrz = 1,2,4-triazole, H₃btc = 1,2,4-benzenetricarboxylate, Bu₄N = tetrabutylammonium], have been synthesized by solvothermal reactions and characterized by single-crystal X-ray diffraction analyses, X-ray power diffraction, elemental analyses, infrared spectra and thermogravimetric analyses. Both compounds 1 and 2 exhibit 3D (3,8)-connected tfz-d nets with {4³}₂{4⁶.6¹⁸.8⁴} topology symbol built from rod-shaped {[Zn₅(trz)₄]⁶⁺}_n SBUs (1) and {[Zn₄(trz)₃]⁵⁺}_n SBUs (2). In two compounds, rodlike units are connected by btc ligands via different modes. Additionally, solid state fluorescent emission spectra of two compounds show fluorescent properties at room temperature.     

3D network structure and spin gap behavior in two new molecular magnets based on bis(maleonitriledithiolato)nickelate monoanion

Two new molecular magnets, based on [Ni(mnt)₂]⁻ monoanion, [DiBrBzPy][Ni(mnt)₂] (1) and [DiBrBzIQl][Ni(mnt)₂] (2) ([DiBrBzPy]⁺ = 1-(3′,5′-dibromobenzyl)pyridinium, [DiBrBzIQl]⁺ = 1-(3′,5′-dibromobenzyl)isoquinolinium and mnt²⁻ = maleonitriledithiolate), were prepared and characterized by elemental analyses, IR, ESI-MS spectra, single crystal X-ray diffraction and magnetic measurements. The [Ni(mnt)₂] anions and the cations of 1 and 2 are alternately stacked and form 1D column via π?π stacking interactions between the [Ni(mnt)₂] anions and the neighboring cations. Some weak Ni?N, C?N interactions and CH?Br, CH?N hydrogen bonds between the adjacent columns further generate a 3D network structure. Magnetic susceptibility measurements show that both 1 and 2 exhibit the typical magnetic behavior of a spin gap system with an energy gap of 1151.9 K for 1 and 73.9 K for 2.     

Syntheses and structures of heterobimetallic complexes derived from [Ga(edt)2] as a metalloligand (edt = SC2H4S): Potential precursors for ternary materials MGaS2 (M = Cu or Ag)

Metathesis reaction between equimolar amount of [Et₄N][GaCl₄] and Na₂edt in methanol resulted in the formation of the dichloro complex [Et₄N][Ga(edt)Cl₂] (1), whereas reaction of [Et₄N][GaCl₄] with two equivalents of Na₂edt in methanol gave the complex [Et₄N][Ga(edt)₂] (2) which can act as a metalloligand. Treatment of 2 with M(PPh₃)₂NO₃ in DMF/CH₂Cl₂ afforded the heterobimetallic complexes [Ga(edt)₂M-(PPh₃)₂] (M = Cu 3, Ag 4) in moderate yields. The structures of 1-4 were determined by single-crystal X-ray diffraction analyses. Both [Ga(edt)Cl₂]⁻ and [Ga(edt)₂]⁻ anions have a distorted tetrahedral geometry. The former consists of one five-membered ring formed by chelating dithiolate and two terminal chloride atoms while the latter consists of two five-membered rings formed by two the chelating dithiolates. Complexes 3 and 4 consist of metalloligand [Ga(edt)₂]⁻ anion chelated to [M(PPh₃)₂]⁺via the sulfur atoms. Both tetrahedrally coordinated Ga and Cu(Ag) atoms are bridged by two sulfur atoms, forming a planar “GaS₂M” (M = Cu, Ag) core. Thermogravimetry analysis revealed that heterobimetallic complexes 3 and 4 decomposed to give the corresponding ternary metal sulfide materials.     

Imidazolium formation from the reaction of N-heterocyclic carbene stabilised group 13 trihydride complexes with organic acids

The reactions of the N-heterocyclic carbene (NHC) stabilised group 13 trihydride complexes [AlH₃(IMeMe)] (1) (IMeMe = 1,3,4,5-tetramethylimidazol-2-ylidene), [AlH₃(IⁱPrMe)] (2) (IⁱPrMe = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) with three molar equivalents of phenol, and [InH₃(IMes)] (3) (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazole-2-ylidene) with one molar equivalent of 1,1,1,5,5,5-hexafluoropentan-2,4-dione (F₆acacH) are presented. These render the imidazolium tetraphenoxyaluminate species; [IMeMe · H][Al(OPh)₄] (4) and [IⁱPrMe · H][Al(OPh)₄] (5), and 1,3-bis(2,4,6-trimethylphenyl)imidazolium 1,1,1,5,5,5-hexafluoropentan-2,4-dionate; [IMes · H][CH{C(O)CF₃}₂] (6), the latter leading to metallohydride decomposition. The molecular structures of 4 and 6 are described.     

Self-assembled diorganotin(IV) moieties with 2,3,4,5-tetrafluorobenzoic acid: Syntheses, characterizations and crystal structures

A series of new organotin(IV) derivatives with 2,3,4,5-tetrafluorobenzoic acid: {[(2,3,4,5-F₄C₆HCO₂)R₂Sn]₂O}₂ (R = Et 1, n-Bu 2, Ph 3), [R₂Sn(O₂CC₆F₄H)₂]_n (R = n-Bu 4, Et 5, Ph 6), and Sn₂R₄(O₂CC₆F₄H)₃(OH) (R = Et 7, n-Bu 8, Ph 9), were synthesized by the reaction of diorganotin oxide and 2,3,4,5-tetrafluorobenzoic acid. All the complexes 1-9 have been characterized by elemental analysis, IR, ¹H, ¹³C, ¹¹⁹Sn NMR spectra. Among them complexes 2, 4, 8 were also characterized by X-ray crystallography diffraction analyses. The crystal structure of complex 2 exhibited a tetra-nuclear geometry with the Sn₂O₂ symmetry core. Complex 4 formed a 1D helical double-chain structure through intermolecular O→Sn coordinating and completed a DNA-like assembly. Complex 8 revealed that the both Sn atoms were held together by hydroxide and acetate bridges, forming a chair-like six-membered ring. Moreover, the supramolecular structures of dimer, 1D chain or 2D network have been found in complexes 4 and 8 by intermolecular C-H?F weak hydrogen bond and non-bonded F?F or F?Sn interaction, which were highly effective in the assembly of supramolecular structures and could lead to the formation of complexes with fascinating topologies properties.     

Synthesis of [SnPh2(SR)2] SR = SC6F4-4-H, SC6F5: Reactivity towards group 10 transition metal complexes

The organometallic tin(IV) complexes [SnPh₂(SR^F)₂] SR^F = ⁻SC₆F₄-4-H (1), ⁻SC₆F₅ (2), were synthesized and their reactivity with [MCl₂(PPh₃)₂] M = Ni, Pd and Pt explored. Thus, transmetallation products were obtained affording polymeric [Ni(SR^F)(μ-SR^F)]_n, monomeric cis-[Pt(PPh₃)₂(SC₆F₄-4-H)₂] (3) and cis-[Pt(PPh₃)₂(SC₆F₅)₂] (4) and dimeric species [Pd(PPh₃)(SC₆F₄-4-H)(μ-SC₆F₄-4-H)]₂ (5) and [Pd(PPh₃)(SC₆F₅)(μ-SC₆F₅)]₂ (6) for Ni, Pt and Pd, respectively. The crystal structures of complexes 1, 2, 3, 4 and 6 were determined.     

Reactivity study of arene(azido)ruthenium N∩O-base complexes with activated alkynes

Substitution reaction of chloro η⁶-arene ruthenium N∩O-base complexes [(η⁶-arene)Ru(N∩O)Cl] [N∩O = pyrazine-2-carboxylic acid (pca-H), 8-hydroxyquinoline (hq-H); arene = p-ⁱPrC₆H₄Me, N∩O = hq (1); arene = C₆Me₆, N∩O = hq (2)] with NaN₃ yield the neutral arene ruthenium azido complexes of the general formula [(η⁶-arene)Ru(N∩O)N₃] [N∩O = pca, arene = p-ⁱPrC₆H₄Me (3), arene = C₆Me₆ (4); N∩O = hq, arene = p-ⁱPrC₆H₄Me (5), arene = C₆Me₆ (6)]. These complexes undergo [3 + 2] dipolar cycloaddition reaction with activated alkynes dimethyl and diethyl acetylenedicarboxylates to yield the arene triazole complexes [(η⁶-arene)Ru(N∩O){N₃C₂(CO₂R)₂}] [N∩O = pca, R = Me, arene = p-ⁱPrC₆H₄Me (7), C₆Me₆ (8); R = Et, arene = p-ⁱPrC₆H₄Me (9), C₆Me₆ (10); N∩O = hq, R = Me, arene = p-ⁱPrC₆H₄Me (11) C₆Me₆ (12); R = Et, arene = p-ⁱPrC₆H₄Me (13), C₆Me₆ (14)]. On the bases of proton NMR study, in the above triazole complexes N(2) isomers are assigned with dimethylacetylenedicarboxylate whereas N(1) isomers with diethylacetylenedicarboxylate. All complexes have been characterized by IR and NMR spectroscopy as well as by elemental analysis. The molecular structures of the azido complexes [(η⁶-p-ⁱPrC₆H₄Me)Ru(pca)N₃] (3), [(η⁶-p-ⁱPrC₆H₄Me)Ru(hq)N₃] (5) and [(η⁶-C₆Me₆)Ru(hq)N₃] (6) have been established by single crystal X-ray diffraction studies.     

Scandium and yttrium complexes of a heteroscorpionate [N,N,O]-donor-set ligand: Synthesis, characterization and catalytic activity in ethylene polymerization

New scandium and yttrium complexes ScL₂(bpzmp)(THF) {L = Cl (1); L = CH₂Si(CH₃)₃ (3)}, YL₂(bpzmp) {L = Cl (2); L = OTf (5)} and Y(CH₂SiMe₃)₂(bpzmp)(THF) (4) bearing the heteroscorpionate bpzmp ligand {bpzmp = (3,5-^tBu₂-2-phenoxo)bis(3,5-Me₂-pyrazol-1-yl)methane} have been synthesized and characterized by means of NMR and Mass spectroscopy. The tridentate monoanionic ligand resulted κ³-coordinated to the metal via the oxygen and both the sp² nitrogen atoms of the heterocycles, producing complexes in C_S symmetry.The behavior of 1-4 in ethylene polymerization was investigated after proper activation with different activating agents. Complex 4, in combination with the Brönsted or Lewis acids [PhNMe₂H][B(C₆F₅)₄] or [Ph₃C][B(C₆F₅)₄], produced linear high molecular weight polyethylene in good yield.     

Rhodium and iridium olefin complexes with bulky cyclopentadienyl and hydrotris(pyrazolyl)borate ligands

The synthesis of a series of rhodium and iridium complexes bearing bulky cyclopentadienyl or hydro(trispyrazolyl)borate ligands is described. The rhodium cyclopentadienyl and hydrotris(pyrazolyl)borate diene compounds, [(η⁵-C₅Me₄Bu^t)Rh(η⁴-2,3-MeRC₄H₄] (R = H, 1; Me, 2) and Tp^MsRh(η⁴-2,3-MeRC₄H₄) (R = H, 3; Me, 4; Tp^Ms is hydrotris(3-mesitylpyrazol-1-yl)borate), respectively, have been prepared from the corresponding Rh(I) diene precursors and Zn(C₅Me₄Bu^t)₂ (for 1 and 2), or TlTp^Ms (for 3 and 4), as effective C₅Me₄Bu^t or Tp^Ms transfer reagents. In contrast with these results, attempts to obtain a bis(ethylene) derivative of the Tp^tolIr(I) unit (Tp^tol stands for hydrotris(3-p-tolylpyrazol-1-yl)borate) have provided instead the Ir(III) complex [(κ⁴-N,N′,N″,C-Tp^tol)-Ir(C₂H₅)(C₂H₄)] (5), whose formation requires C-H bond activation of a molecule of ethylene and of one of the Tp^tolp-tolyl substituents. In refluxing toluene 5 experiences metalation of a second p-tolyl substituent to give [(κ⁵-N,N′,N″,C,C′-Tp^tol)-Ir(C₂H₄)] (6), which features unusual κ⁵-Tp^tol coordination. The latter compound reacts with carbon monoxide to yield the corresponding carbonyl, 7.     

Palladium(II), platinum(II), ruthenium(II) and mercury(II) complexes of potentially tridentate Schiff base ligands of (E, N, O) type (E = S, Se, Te): Synthesis, crystal structures and applications in Heck and Suzuki coupling reactions

Schiff bases of 2-hydroxybenzophenone (HBP) (C₆H₅)(2-HOC₆H₄)CN(CH₂)_nEAr (L1/L2: E = S, Ar = Ph, n = 2/3; L3/L4: E = Se, Ar = Ph, n = 2/3; L5/L6: E = Te, Ar = 4-MeOC₆H₄, n = 2/3) and their complexes [PdCl(L-H)] (L = L1−L6; 1, 2, 3, 5, 7, 11), [PtCl(L3-H/L5-H)] (4/8), [PtCl₂(L4/L6)₂] (6/12), [(p-cymene)RuCl(L5/L6)]Cl (9/13) and [HgBr₂(L5/L6)₂] (10/14) have been synthesized and characterized by proton, carbon-13, selenium-77 and tellurium-125 NMR, IR and mass spectra. Single crystal structures of L1, 1, 3, 4, 5 and 7 were solved. The Pd-E bond distances (Å): 2.2563(6) (E = S), 2.3575(6)−2.392(2) (E = Se); 2.5117(5)−2.5198(5) (E = Te) are near the lower end of the bond length range known for them. The Pt-Se bond length, 2.3470(8) Å, is also closer to the short values reported so far. The Heck and Suzuki reaction were carried out using complexes 1, 3, 5 and 7 as catalysts under aerobic condition. The percentage yields for trans product in Heck reaction were found upto 85%.     

New phospholyl complexes of groups 4 and 6: Syntheses, characterisation and polymerisation studies

[M(P₃C₂^tBu₂)(CO)₃I] (M = Mo, 1, W, 2) have been synthesised and reacted with PCl₅ for oxidation study purposes. Compounds Ti(P₃C₂^tBu₂)(Ind)Cl₂], 3, and [Zr(P₃C₂^tBu₂)(Cp)Cl₂], 4, were detected spectroscopically, but showed to be too unstable to be isolated. A Ti(IV) complex, [Ti(P₃C₂^tBu₂)Cl₃], 5, has been formed from the reaction of [TiCl₄] with the base-free ligand K(P₃C₂^tBu₂), while the Ti(III) species, [Ti(P₃C₂^tBu₂) Cl₂(THF)], 6, was prepared from [TiCl₃(THF)₃]. Compounds 5 and 6 were studied as ethylene catalyst precursors after activation with MAO. In the studied conditions, complex 5 is the most active one with an activity of 2.2 × 10⁵ g(molTi [E] h)⁻¹, one order of magnitude higher than compound 6. The produced polymer is linear polyethylene.