Parent-amido (NH2) palladium(II) complexes: Synthesis,reactions, and catalytic hydroamination

The treatment of [PdL₃(NH₃)](OTf)_n (n = 1; L₃ = (PEt₃)₂(Ph), (2,6-(Cy₂PCH₂)₂C₆H₃), n = 2; L₃ = (dppe)(NH₃)) with NaNH₂ in tetrahydrofuran at ambient temperature or −78 °C afforded the dimeric and monomeric parent-amido palladium(II) complexes anti-[Pd(PEt₃)(Ph)(μ-NH₂)]₂ (1), [Pd(dppe)(μ-NH₂)]₂(OTf)₂ (2), and Pd(2,6-(Cy₂PCH₂)₂C₆H₃)(NH₂) (3), respectively. The molecular structures of the amido-bridged (μ-NH₂) dimeric complexes 1 and 2 were determined by single-crystal X-ray crystallography. The monomeric amido complex 3 reacted with trace amounts of water to give a hydroxo complex, Pd(2,6-(Cy₂PCH₂)₂C₆H₃)(OH) (4). Exposing complex 3 to an excess of water resulted in the complete conversion of the complex into two species [Pd(2,6-(Cy₂PCH₂)₂C₆H₃)(OH₂)]⁺ and [Pd(2,6-(Cy₂PCH₂)₂C₆H₃)(NH₃)]⁺. Complex 3 reacted with diphenyliodonium triflate ([Ph₂I]OTf) to give the aniline complex [Pd(2,6-(Cy₂PCH₂)₂C₆H₃)(NH₂Ph)]OTf. The reaction of 3 with phenylacetylene (HCCPh) yielded a palladium(II) acetylenide Pd(2,6-(Cy₂PCH₂)₂C₆H₃)(CCPh) (5), quantitatively, along with the liberation of ammonia. The reaction of 3 with dialkyl acetylenedicarboxylate yielded diastereospecific palladium(II) vinyl derivatives (Z)-Pd(2,6-(Cy₂PCH₂)₂C₆H₃)(CRCR(NH₂)) (R = CO₂Me (6a), CO₂Et (6b)). The reaction of complexes 6a and 6b with p-nitrophenol produced Pd(2,6-(Cy₂PCH₂)₂C₆H₃)(OC₆H₄-p-NO₂) (7) and cis-CHRCR(NH₂), exclusively. Reactions of 3 with either dialkyl maleate (cis-(CO₂R)CHCH(CO₂R)) (R = CH₃, CH₂CH₃) or cis-stilbene (cis-CHPhCHPh) did not result in any addition product. Instead, isomerization of the cis-isomers to the trans-isomers occurred in the presence of catalytic amounts of 3. Complex 3 reacted with a stoichiometric amount of acrylonitrile (CH₂CHCN) to generate a metastable insertion product, Pd(2,6-(Cy₂PCH₂)₂C₆H₃)(CH(CN)CH₂NH₂). On the other hand, the reaction of 3 with an excess of acrylonitrile slowly produced polymeric species of acrylonitrile. The catalytic hydroamination of olefins with NH₃ was examined in the presence of Pd(2,6-(Cy₂PCH₂)₂C₆H₃)(OTf), producing a range of hydroaminated products of primary, secondary, and tertiary amines with different molar ratios of more than 99% overall yield. A mechanistic feature for the observed catalytic hydroamination is described with regard to the aminated derivatives of palladium(II).     

Synthesis,X-ray structure and reactivity of μ-(CF3COO)2-[Mo(N-2,6-i-Pr2-C6H3)(CHCMe2Ph)(OOCCF3)(Et2O)]2, the first Bis(trifluoroacetate) derivative of a Schrock catalyst

Reaction of Mo(N-2,6-i-Pr₂-C₆H₃)(CHCMe₂C₆H₅)(OSO₂CF₃)(DME) (DME = 1,2-dimethoxyethane) with 2 equiv. of CF₃COOK yields μ-(CF₃COO)₂-[Mo(N-2,6-i-Pr₂-C₆H₃)(CHCMe₂Ph)(OOCCF₃)(Et₂O)]₂ (1). Compound 1 crystallizes in the orthorhombic space group Pna2₁ with a = 17.2485(3), b = 17.0336(3), c = 25.4031(5) Å, α = β = γ = 90°, V = 7463.5(2) Å³, Z = 4. In contrast to alkoxide based Schrock type initiators, 1 is virtually inactive in numerous metathesis reactions including ring-closing metathesis (RCM) and homo metathesis reactions, the cyclopolymerization of 1,6-heptadiynes, and even ring-opening metathesis polymerization (ROMP) of norborn-2-ene. However, addition of quinuclidine results in the in situ formation of 1a (Mo(N-2,6-i-Pr₂-C₆H₃)(CHCMe₂C₆H₅)(OOCCF₃)₂(quinuclidine) which displays moderate activity in ROMP, cyclopolymerization of 1,6-heptadiynes and RCM. Theoretical investigations carried out on the B3LYP/LACVP¹ level provide substantial explanation for these findings.     

Magnetic properties of hybrid organo-inorganic copper(II) oxovanadate(V) phosphate and phosphonate bridged systems

The hybrid organo-inorganic compounds [Cu₄(bipy)₄V₄O₁₁(PO₄)₂]nH₂O (n ∼ 5) (1), [Cu₂(phen)₂(PO₄)(H₂PO₄)₂(VO₂) · 2H₂O] (2) and [Cu₂(phen)₂(O₃PCH₂PO₃)(V₂O₅) (H₂O)]H₂O (3) which present different bridging forms of the phosphate/phosphonate group, show different bulk magnetic properties. We herein analyze the magnetic behaviour of these compounds in terms of their structural parameters. We also report a theoretical study for compound (1) assuming four different magnetic exchange pathways between the copper centres present in the tetranuclear unit. For compound (1) the following J values were obtained J₁ = +3.29; J₂ = −0.63; J₃ = −2.23; J₄ = −46.14 cm⁻¹. Compound (2) presents a Curie–Weiss behaviour in the whole range of temperature (3–300 K), and compound (3) shows a maximum for the magnetic susceptibility at 64 K, typical for antiferromagnetic interactions. These data where fitted using a model previously reported in the literature, assuming two different magnetic exchange pathways between the four copper(II) centres, with J₁ = −30.0 and J₂ = −8.5 cm⁻¹.     

Novel Fe (III) heterochelates: Synthesis,structural features and fluorescence studies

Fluorescence properties of five 4-acyl pyrazolone based hydrazides (H₂SB_n) and their Fe (III) heterochelates of the type [Fe(SB_n)(L)(H₂O)]·mH₂O [H₂SB_n = nicotinic acid [1-(3-methyl-5-oxo-1-phenyl-4,5-di hydro-1H-pyrazol-4yl)-acylidene]-hydrazide; where acyl = –CH₃, m = 4 (H₂SB₁); –C₆H₅, m = 2 (H₂SB₂); –CH₂–CH₃, m = 3 (H₂SB₃); –CH₂–CH₂–CH₃, m = 1.5 (H₂SB₄); –CH₂–C₆H₅, m = 1.5 (H₂SB₅) and HL = 1-cyclopropyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydroquinoline-3-carboxylic acid] were studied at room temperature. The fluorescence spectra of heterochelates show red shift, which may be due to the chelation by the ligands to the metal ion. It enhances ligand ability to accept electrons and decreases the electron transition energy. The kinetic parameters such as order of reaction (n), energy of activation (E_a), entropy (S*), pre-exponential factor (A), enthalpy (H*) and Gibbs free energy (G*) have been reported.     

Synthesis and characterization of a novel three-dimensional open-framework: Metal diphosphonate,Zn[HO3PCH2(C6H4)CH2PO3H]

A novel zinc diphosphonate, Zn[HO₃PCH₂(C₆H₄)CH₂PO₃H] (1) was synthesized from tetraethyl para-xylylenediphosphonate, Et₂O₃PCH₂C₆H₄CH₂PO₃Et₂, and Zn (AcO)₂·2H₂O under solvothermal conditions. The structure of compound 1 was determined by single-crystal X-ray diffraction, which reveals that the structure crystallizes in the monoclinic space group C2/c (No. 15), with a = 22.4844(19) Å, b = 6.4361(5) Å, c = 8.1194(7) Å, β = 102.595(2)°, V = 1146.70(16) Å³, T = 298(2) K, Z = 8. The novel three-dimensional (3D) construction is simply built up from linear inorganic chains of corner-sharing four-rings of tetrahedral [ZnO₄] and [PO₃C] which connected adjacent chains by the organophosphorus ligand para-xylylenediphosphonate. The framework has 10 Å × 4 Å (containing the van der Waals radii of atoms) channels running along the b-axis.     

New α,ω-dicarboxylate coordination polymers with 4,4′-bipyridine: Cu(bpy)(C5H6O4), Zn(bpy)(C5H6O4), Zn(bpy)(C6H8O4) and Mn(bpy)(C8H12O4) · H2O

Four 4,4′-bipyridine α,ω-dicarboxylate coordination polymers Cu(bpy)(C₅H₆O₄) (1), Zn(bpy)(C₅H₆O₄) (2), Zn(bpy)(C₆H₈O₄) (3) and Mn(bpy)(C₈H₁₂O₄) · H₂O (4) have been synthesized and structurally characterized by single crystal X-ray diffraction methods (bpy = 4,4-bipyridine, (C₅H₆O₄)²⁻ = glutarate anion, (C₆H₈O₄)²⁻ = adipate anion, (C₈H₁₂O₄)²⁻ = suberate anion). Their crystal structures are featured by dimeric metal units, which are co-bridged by 4,4′-bipyridine ligands and dicarboxylate anions such as glutarate, adipate and suberate anions to generate 2D layers with a (4,4) topology in 1, 2 and 4 as well as to form 3D frameworks in 3. Two 3D frameworks in 3 interpenetrate with each other to form a topology identical to the well-known Nb₆F₁₅ cluster compound. Over 5–300 K, the paramagnetic behavior of 4 follows the Curie–Weiss law χ_m(T − Θ) = 4.265(5) cm³ mol⁻¹ with the Weiss constant Θ = −6.3(2) K. Furthermore, the thermal behavior of 3 and 4 is also discussed.     

Palladium(II) complexes with the new P,N-type ligand (2-oxazoline-2-ylmethyl)di-isopropylphosphine as intermediates in CO/ethylene or CO/methyl acrylate insertion

The ligand (i-Pr)₂PCH₂(oxazoline) (1a), of the P,N-donor type, was reacted with [PdMeCl(COD)] to yield the square planar methylpalladium(II) complex [PdClMe(P,N)] (P,N = 1a) (2a), from which the complex [PdMe(P,N)OTf] (OTf = OSO₂CF₃) (3a) was obtained by AgOTf-promoted chloride abstraction. The alkyl complexes

(P,N = 1a) (5a, R = H; 7a, R = C(O)OMe) have been isolated from the initial CO/ethylene or CO/methyl acrylate insertion steps into the Pd–Me bond of 3a, respectively, and spectroscopically characterized. Complexes 2a, 3a and 7a have been fully characterized by single crystal X-ray diffraction. Complex 7a is still a rare example of a structurally characterized CO/methyl acrylate stepwise insertion product. These complexes are relevant to the alternating copolymerization of olefins and carbon monoxide catalyzed by palladium complexes. In addition, the centrosymmetric dinuclear complex trans-[Pd(μ-Cl){(i-Pr)₂PCH₂(oxazoline)}]₂(OTf)₂ (6) has been obtained and characterized by X-ray diffraction; it appears to be the first dinuclear complex of the type [Pd(μ-Cl)(P,N)]₂ to be characterized by X-ray crystallography.

Résumé

Le ligand (i-Pr)₂PCH₂(oxazoline) (1a), de type donneur P,N, réagit avec [PdClMe(COD)] pour former le complexe plan carré méthylpalladium(II) [PdClMe(P,N)] (P,N = 1a) (2a), à partir duquel le complexe [PdMe(P,N)OTf] (OTf = OSO₂CF₃) (3a) a été obtenu par abstraction de chlorure à l'aide de AgOTf. Les complexes alkyles

(P,N = 1a) (5a, R = H; 7a, R = C(O)OMe), ont été isolés lors des premières étapes d'insertion de CO/éthylène ou de CO/acrylate de méthyle, respectivement, dans la liaison Pd–Me de 3a, et caractérisés par méthodes spectroscopiques. Les complexes 2a, 3a et 7a ont été complètement caractérisés par diffraction des rayons X sur monocristal. Le complexe 7a est un exemple encore rare de produit d'insertion par étapes de CO/acrylate de méthyle qui ait été caractérisé structuralement. Ces complexes sont pertinents pour la copolymérisation alternée d'oléfines et de monoxyde de carbone catalysée par les complexes du palladium. En outre, le complexe dinucléaire centrosymétrique trans-[Pd(μ-Cl){(i-Pr)₂PCH₂(oxazoline)}]₂(OTf)₂ (6) a été obtenu et caractérisé par diffraction des rayons X; il s'agit du premier complexe dinucléaire de type [Pd(μ-Cl)(P,N)]₂ à être caractérisé par diffraction des rayons X.     

Dialkyl- and diaryl-platinum(II) complexes with secondary phosphines: Preparation,structure and thermal reaction giving the metallopolymer

Alkyl and arylplatinum complexes with 1,5-cyclooctadiene ligand, [PtR₂(cod)] (R = Me, Ph, C₆H₄-p-CF₃, C₆F₅), react with secondary phosphines, PHR′₂ (R′ = i-Bu, t-Bu, Ph), to afford the mononuclear platinum complexes, cis-[PtR₂(PHR′₂)₂] (1a: R = Me, R′ = i-Bu; 1b: R = Me, R′ = t-Bu; 1c: R = Me, R′ = Ph; 2a: R = Ph, R′ = i-Bu; 2b: R = Ph, R′ = t-Bu; 2c: R = R′ = Ph; 3a: R = C₆H₄-p-CF₃, R′ = i-Bu; 3b: R = C₆H₄-p-CF₃, R′ = t-Bu; 3c: R = C₆H₄-p-CF₃, R′ = Ph; 4a: R = C₆F₅, R′ = i-Bu; 4c: R = C₆F₅, R′ = Ph) in 81–98% yields. Molecular structures of the complexes except for 1a, 1c and 2a were determined by X-ray crystallography. Complex 1b has a square-planar structure with Pt–C(methyl) bonds of 2.083(8) and 2.109(8) Å, while the Pt–C(aryl) bonds of 2b–c, 3a–c, 4a and 4c (2.055(1)–2.073(8) Å) are shorter than them. Thermal decomposition of 1b, 2a–c, and 3a–c releases methane, biphenyl or 4,4′-bis(trifluoromethyl)biphenyl as the organic products, which are characterized by NMR spectroscopy. The solid product of the thermal reactions of 2b and 2c were characterized as the metallopolymers formulated as [Pt(PR′₂)₂]_n (5b: R′ = ^tBu; 5c: R′ = Ph), based on the solid-state NMR and elemental analyses.     

Versatile Ru-based metathesis catalysts designed for both homogeneous and heterogeneous processes

The synthesis of new ruthenium-based catalysts applicable for both homogeneous and heterogeneous metathesis is described. Starting from the Hoveyda-Grubbs first generation (1) and the Hoveyda-Grubbs second generation (2) catalysts the homogeneous catalysts [RuCl((RO)₃Si–C₃H₆–N(R′)–CO–C₃F₆–COO)(CH–o-O–iPr–C₆H₄)(SIMes)] (4: R = Et, R′ = H; 5: R = R′ = Me) (SIMes = 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene) were prepared by substitution of one chloride ligand with trialkoxysilyl functionalized silver carboxylates (RO)₃Si–C₃H₆–N(R′)–CO–C₃F₆–COOAg (3a: R = Et, R′ = H; 3b: R = R′ = Me). These homogeneous ruthenium-species are among a few known examples with mixed anionic ligands. Exchange of both chloride ligands afforded the catalysts [Ru((RO)₃Si–C₃H₆–N(R′)–CO–C₃F₆–COO)(CH–o-O–iPr–C₆H₄)(SIMes)] (9: R = Et, R′ = H; 11: R = R′ = Me) and [Ru((RO)₃Si–C₃H₆–N(R′)–CO–C₃F₆–COO)(CH–o-O–iPr–C₆H₄)(PCy₃)] (8: R = Et, R′ = H; 10: R = R′ = Me). The reactivity of the new complexes was tested in homogeneous ring-closing metathesis (RCM) of N,N-diallyl-p-toluenesulfonamide and TONs of up to 5000 were achieved. Heterogeneous catalysts were obtained by reaction of 4, 5 and 8–11 with silica gel (SG-60). The resultant supported catalysts 4a, 5a, 8a–11a showed reduced activity compared to their homogenous analogues, but rival the activity of similar heterogeneous systems.     

Synthesis of palladium–biscarbene complexes derived from 1,1′-methylenebis(1,2,4-triazole) functionalized in the methylene bridge

Palladium–biscarbene complexes derived from N,N′-bis(1,2,4-triazol-1-yl)methane, which bear an alkyl chain functionalized with a hydroxyl group, have been synthesized ([Pd(L1)Br₂] (6) and [Pd(L1)I₂] (7) [L1 = 1,1′-(3-hydroxypropylidene)bis(4-butyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene)]). Each product is obtained as a non-equimolecular mixture of two conformers. The hydroxyl group has been replaced by bromide and methanesulphonate and ( [Pd(L2)Br₂] [L2 = 1,1′-(3-bromopropylidene)bis(4-butyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene)] (9)) and ([Pd(L3)Br₂] [L3 = 1,1′-(3-methanesulphonyloxypropylidene)-bis(4-butyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene)] (10)) were obtained, respectively, as mixtures of conformers. All compounds consist of a six-membered metallacyclic structure in a boat conformation. Major conformers present the functionalized chain in the axial position, while in minor conformers it is located in the equatorial position.     

Synthesis of heteronuclear (MoRu2) clusters from 16-electron half-sandwich complexes (p-Cymene)Ru[E2C2(B10H10)] (E = S,Se)

The heterometallic cluster complexes {(p-Cymene)Ru[S₂C₂(B₁₀H₁₀)]}Mo(CO)₂{(CO)₃Ru[S₂C₂(B₁₀H₁₀)]} (2) and {(p-Cymene)Ru[Se₂C₂(B₁₀H₁₀)]}₂Mo(CO)₂ (3) (p-Cymene = η⁶-4-isopropyl-toluene) have been synthesized from the reactions of 16-electron half-sandwich ruthenium 1,2-dichalcogenolate carborane complexes (p-Cymene)Ru[E₂C₂(B₁₀H₁₀)] (E = S(1a), Se(1b)) with Mo(CO)₃(Py)₃ in the presence of BF₃ · Et₂O. The complexes of 2 and 3 were characterized by elemental analysis and IR, NMR spectra. The molecular structure of 2 has been characterized by single-crystal X-ray diffraction analysis. Complex 2 is unsymmetrical and the two Ru–Mo single bonds (2.7893(14), 2.8189(13) Å) are each supported by a symmetrically bridging o-carborane-1,2-dithiolato ligand.     

Reactivity of intramolecularly coordinated aluminum compounds to R3EOH (E = Sn,Si). Remarkable migration of N,C,N and O,C,O pincer ligands

The reaction of organoaluminum compounds containing O,C,O or N,C,N chelating (so called pincer) ligands [2,6-(YCH₂)₂C₆H₃]AlⁱBu₂ (Y = MeO 1, ^tBuO 2, Me₂N 3) with R₃SnOH (R = Ph or Me) gives tetraorganotin complexes [2,6-(YCH₂)₂C₆H₃]SnR₃ (Y = MeO, R = Ph 4, Y = MeO, R = Me 5; Y = ^tBuO, R = Ph 6, Y = ^tBuO, R = Me 7; Y = Me₂N, R = Ph 8, Y = Me₂N, R = Me 9) as the result of migration of O,C,O or N,C,N pincer ligands from aluminum to tin atom. Reaction of 1 and 2 with (ⁿBu₃Sn)₂O proceeded in similar fashion resulting in 10 and 11 ([2,6-(YCH₂)₂C₆H₃]SnⁿBu₃, Y = MeO 10; Y = ^tBuO 11) in mixture with ⁿBu₃SnⁱBu. The reaction 1 and 3 with 2 equiv. of Ph₃SiOH followed another reaction path and ([2,6-(YCH₂)₂C₆H₃]Al(OSiPh₃)₂, Y = MeO 12, Me₂N 13) were observed as the products of alkane elimination. The organotin derivatives 4–11 were characterized by the help of elemental analysis, ESI-MS technique, ¹H, ¹³C, ¹¹⁹Sn NMR spectroscopy and in the case 6 and 8 by single crystal X-ray diffraction (XRD). Compounds 12 and 13 were identified using elemental analysis,¹H, ¹³C, ²⁹Si NMR and IR spectroscopy.     

Structure and magnetic properties of a novel copper diphosphonate with pillared layered structure:: Cu2(H2O)2{O3PCH2N(C2H4)2NCH2PO3}

Compound Cu₂(H₂O)₂{O₃PCH₂N(C₂H₄)₂NCH₂PO₃} (1) has a pillared layered structure in which the organic groups of N,N′-piperazinebis(methylenephosphonate) are sandwiched between the inorganic layers. Compared with other copper phosphonates with layered or pillared layered structures, the inorganic layer in 1 is unique in that each {CPO₃} tetrahedron is corner-shared with three {CuO₄N} square pyramids through three oxygen donors. Ferromagnetic interactions are mediated between the metal centers. Crystal data: Pbca, a=10.0830(16) Å, b=9.4517(15) Å, c=13.218(2) Å, V=1259.7(3) Å³, Z=4.     

Supramolecular chemistry and the control of the crystallization behavior by the choice of the counter-ion. Part 11. The stereochemistry and crystallization architecture of [(tren)Co(NO2)2]A (I), [(tren)Co(ox)]A (II), [(en)2Co(ox)]A (III) and [trans-(pn)2Co(NO2)2]A (IV), with A = [trans-(NH3)2Co(NO2)4]

In continuation of studies carried out previously [I. Bernal, Inorg. Chim. Acta 96 (1985) 99; I. Bernal, Inorg. Chim. Acta (1986) 121; I. Bernal, E.O. Schlemper, C.K. Fair, Inorg. Chim. Acta 115 (1986) 25; I. Bernal, Inorg. Chim. Acta 101 (1985) 175; I. Bernal, J. Cetrullo, J. Coord. Chem. 20 (1989) 237], we have now expanded the nature and number of cations associated with the [trans-(NH₃)₂Co(NO₂)₄] anion in order to better document when, and how, this helical propeller species crystallizes as a conglomerate.[(tren)Co(NO₂)₂][trans-(NH₃)₂Co(NO₂)₄] (I) crystallizes as a racemate in space group P2₁/n with cell constants of a = 15.8900(2), b = 19.7800(3), c = 26.6200(4) Å, β = 101.970(3)°, z = 15.[(tren)Co(ox)][trans-(NH₃)₂Co(NO₂)₄] (II) crystallizes as a racemate in space group I2/a with cell constants of a = 21.592(11), b = 7.050(4), c = 26.46(2) Å, β = 93.09(6)°, z = 8.[(en)₂Co(ox)][trans-(NH₃)₂Co(NO₂)₄] (III) crystallizes as a racemate in space group P2₁/n with cell constants of a = 6.4740(1), b = 22.8950(6), c = 13.1660(3) Å, β = 97.3310(10)°, z = 4.[trans-(pn)₂Co(NO₂)₂][trans-(NH₃)₂Co(NO₂)₄] (IV) also crystallizes as a racemate in space group P(¯1; no. 2) with cell constants of a = 6.508(2), b = 8.829(5), c = 9.851(5) Å, α = 72.84(2), β = 80.15(3), and γ = 81.45(6)°, z = 1.The most notable results are as follows: (1) all four compounds studied are racemates unlike the previously studied [cis-Co(en)₂(NO₂)₂][trans-(NH₃)₂Co(NO₂)₄] [I. Bernal, Inorg Chim Acta 101 (1985) 175] (V) and K[trans-(NH₃)₂Co(NO₂)₄] (VI) that crystallize as conglomerates. Nevertheless, they share certain crystalline features, which are readily observed in their packing diagrams.In all the four cases the new data were collected at 295 K and 120 K, using Mo Kα radiation; the former with a Nonius CAD-4 diffractometer and the latter with a Nonius CCD instrument. Of primary interest to us are the changes in packing caused by repeated changes in the charge compensating cations. Comparisons with the packing observed previously in [cis-Co(en)₂(NO₂)₂][trans-(NH₃)₂Co(NO₂)₄] (V) and K[trans-(NH₃)₂Co(NO₂)₄] (VI) are made since, at the time of publications of those early papers, no detailed study of the packing characteristics of these anions was published and the existing graphic software were primitive compared with the current packages. This oversight is remedied below.     

Synthesis and characterization of novel intramolecularly O,C,O-coordinated heteroleptic organostannylenes and their tungstenpentacarbonyl complexes

The syntheses are reported of the novel heteroleptic organostannylenes [2,6-(ROCH₂)₂C₆H₃]SnCl (1, R = Me; 2, R = t-Bu) and of their tungstenpentacarbonyl complexes [2,6-(ROCH₂)₂C₆H₃](X)SnW(CO)₅ (3, X = Cl, R = Me; 4, X = Cl, R = t-Bu; 5, X = H, R = Me). The compounds were characterized by means of elemental analyses, ¹H, ¹³C, ¹¹⁹Sn NMR spectroscopies, electrospray mass spectrometry and in case of 3 and 4 also by single crystal X-ray diffraction analysis. For the two latter compounds the substituents bound at the ether oxygen atom control the strength of intramolecular O → Sn coordination. Thus, the O–Sn distances amount to 2.391(5)/2.389(5) (3) and 2.464(3)/2.513(3) Å (4).     

Comparative study of two layered lanthanide dicarboxylates based on europium(III) dimers

The new rare-earth dicarboxylate solid Eu₂(H₂O)₄{C₆H₁₀–(CO₂)₂}₃·2H₂O or MIL-94 has been isolated under hydrothermal conditions. Its layered structure, which was solved using X-ray powder diffraction data, is built up from dimers of nine-coordinated edge-sharing polyhedra linked through 1,3-cyclohexane dicarboxylate (1,3-CHC) moieties. A comparative study of MIL-94 and the layered lanthanide dicarboxylate EuBDC or Eu₂(H₂O)₂{C₆H₄–(CO₂)₂}₃, which is built up from dimers of corner-sharing polyhedra and 1,3-benzenedicarboxylate (1,3-BDC) linkers, is also reported. Crystal data for MIL-94: orthorhombic space group Pnma (no. 62) with a = 8.8470(1) Å, b = 25.0148(1) Å, c = 14.3716(4) Å and Z = 4. MIL stands for Material Institut Lavoisier.     

Mono(amidinate) rare earth metal bis(alkyl) complexes: Synthesis,structure and their activity for l-lactide polymerization

Alkane elimination reaction between Ln(CH₂SiMe₃)₃(THF)₂ (Ln = Y, Lu) with one equivalent of the amidines with different steric demanding HL ([CyC(N-2,6-ⁱPr₂C₆H₃)₂]H (HL₁), [CyC(N-2,6-Me₂C₆H₃)₂]H (HL₂), [PhC(N-2,6-Me₂C₆H₃)₂]H (HL₃)) in THF afforded a series of mono(amidinate) rare earth metal bis(alkyl) complexes [CyC(N-2,6-ⁱPr₂C₆H₃)₂]Ln(CH₂SiMe₃)₂(THF) (Ln = Y (1), Lu (3)), [CyC(N-2,6-Me₂C₆H₃)₂]Ln(CH₂SiMe₃)₂(THF)₂ (Ln = Y (4), Lu (6)), and [PhC(N-2,6-Me₂C₆H₃)₂]Y(CH₂SiMe₃)₂(THF)₂ (7) in 75–89% isolated yields. For the early lanthanide metal Nd, THF slurry of NdCl₃ was stirred with three equiv of LiCH₂SiMe₃ in THF, followed by addition of one equiv of the amidines HL₁ or HL₂ gave an “ate” complex [CyC(N-2,6-ⁱPr₂C₆H₃)₂]Nd(CH₂SiMe₃)₂(μ-Cl)Li(THF)₃ (2) in 48% yield and a neutral [CyC(N-2,6-Me₂C₆H₃)₂]Nd(CH₂SiMe₃)₂(THF)₂ (5) in 52% yield, respectively. They were characterized by elemental analysis, FT-IR, NMR spectroscopy (except for 2 and 5 for their strong paramagnetic property). Complexes 2, 3, 4 and 5 were subjected to X-ray single crystal structure determination. These neutral mono(amidinate) rare earth metal bis(alkyl) complexes showed activity towards l-lactide polymerization to give high molecular weight and narrow molecular weight distribution polymers.     

Two novel Keggin tungstocobaltates grafted by cobaltII complex group(s): K[Co(phen)2(H2O)]2[HCoW12O40]·2H2O and [Co(2,2′-bipy)3]1.5{[Co(2,2′-bipy)2(H2O)][HCoW12O40]}·0.5H2O

Two novel inorganic–organic hybrid compounds composed of Keggin tungstocobaltate framework and cobalt(II)–N coordination complexes, K[Co(phen)₂(H₂O)]₂[HCoW₁₂O₄₀]·2H₂O (1) (phen = 1,10-phenanthroline) and [Co(2,2′-bipy)₃]_1.5{[Co(2,2′-bipy)₂(H₂O)][HCoW₁₂O₄₀]·0.5H₂O (2) (bipy = bipyridine), have been synthesized under hydrothermal conditions by directly using Keggin POMs as starting materials, which were characterized by elemental analyses, IR, TG analyses and X-ray single crystal diffraction. Crystal data for compound 1: C₄₈H₄₁Co₃KN₈O₄₄W_12, triclinic, space group P-1, a = 10.918(5) Å, b = 13.401(5) Å, c = 13.693(5) Å, α = 69.291(5)°, β = 71.568(5)°, γ = 78.421(5)°, V = 1768.9(12) Å³, Z = 1; for compound 2: C₁₃₀H₁₀₄Co₇N₂₆O₈₃W_24, orthorhombic, space group, C2/c, a = 46.839(9) Å, b = 14.347(3) Å, c = 26.147(5) Å, α = β = γ = 90°, V = 17,570(6) Å³, Z = 4. Compound 1 exhibits a pseudo-1D chainlike structure, in which potassium ions act as linkages of Keggin unit doubly grafted by [Co(phen)₂(H₂O)] complex. Compound 2 represents a [Co(2,2′-bipy)₂(H₂O)]²⁺ mono-grafted Keggin tungstocobaltate derivative with 1.5[Co(2,2′-bipy)₃]²⁺ countercations. The cyclic voltammetric behavior of 1-CPE is similar to the parent 3-CPE, but the cyclic voltammetric behavior of Co^II shows a little difference. Variable-temperature magnetic susceptibility measurement of compound 1 demonstrates the presence of antiferromagnetic interactions.     

Pentamethylcyclopentadienyl ruthenium(II) complexes of para-substituted N-(pyrid-2-ylmethylene)-phenylamine ligands: syntheses,spectral and structural studies

The reaction of [(η⁵-C₅Me₅)Ru(PPh₃)₂Cl] (1) with acetonitrile in the presence of excess NH₄PF₆ leads to the formation of the cationic ruthenium(II) complex [(η⁵-C₅Me₅)Ru(PPh₃)₂(CH₃CN)]PF₆ (2). The complex (2) reacts with a series of N,N′ donor Schiff base ligands viz. para-substituted N-(pyrid-2-ylmethylene)-phenylamines (ppa) in methanol to yield pentamethylcylopentadienyl ruthenium(II) Schiff base complexes of the formulation [(η⁵-C₅Me₅)Ru(PPh₃)(C₅H₄N-2-CHN-C₆H₄-p-X)]PF₆ [3a]PF₆–[3f]PF₆, where C₅Me₅ = pentamethylcylopentadienyl, X = H, [3a]PF₆, Me, [3b]PF₆, OMe, [3c]PF₆, NO₂, [3d]PF₆, Cl, [3e]PF₆, COOH, [3f]PF₆. The complexes were isolated as their hexafluorophosphate salts. The complexes were fully characterized on the basis of elemental analyses and NMR spectroscopy. The molecular structure of a representative complex, [(η⁵-C₅Me₅)Ru(PPh₃)(C₅H₄N-2-CHN-C₆H₄-p-Cl)]PF₆ [3e]PF₆, has been established by X-ray crystallography.     

Heterofunctionalized phosphines derived from (2-formylphenyl)diphenylphosphine and their reactions with oxorhenium(V) complexes

Reactions of [ReOCl₃(PPh₃)₂] with a potentially tridentate Schiff base derived from (2-formylphenyl)diphenylphosphine and 2-aminophenol, HL¹P, (HL¹P = Ph₂PC₆H₄-2-HCN(C₆H₄-2-OH)) result in a rapid decomposition of the Schiff base and the formation of a large number of hitherto non-identified metal-containing species, while from similar reactions with the analogoue phosphine oxide HL¹PO, (HL¹PO = Ph₂P(O)C₆H₄-2-HCN(C₆H₄-2-OH)) products of the compositions [ReOCl₂(PPh₃)(L¹PO)] (1) and [Re(NC₆H₄-2-OH)Cl₃(PPh₃)₂] (2) could be isolated. The structure of 2 is an experimental proof of the preceding, metal-induced cleavage of the C–N double bond. A subsequent reaction of the released 2-aminophenol forms the final phenylimido ligand.Reduction of HL¹P with NaBH₄ gives the phosphine amine H₂L²P (H₂L² = Ph₂P(C₆H₄-2-CH₂NH(C₆H₄-2-OH))) in good yield. Reactions of H₂L²P with common oxorhenium(V) complexes result in the formation of the stable rhenium(V) complex [ReOCl₂(HL²P)] (3) with a facially coordinated HL²P^? ligand.