Four distinctive 1-D lanthanide carboxylate coordination polymers: Synthesis,crystal structures and spectral properties

Four novel lanthanide coordination polymers [Pr(mal)(OH)(bipy) · 2H₂O]_n (1), {[Dy¹(SBA)₃(H₂O)₂][Dy²(SBA)₃(H₂O)₂] · 4H₂O}_n (2), {[Tb(OHnic)(Onic)(H₂O)₅ · (OHnicH)] · H₂O}_n (3) and {[Sm(OHnic)(Onic)(H₂O)₅ · (OHnicH)] · H₂O}_n (4) (Hmal = maleic acid, HSBA = 4-sulfobenzoic acid, OHnicH = 6-hydroxynicotinic acid and bipy = 2,2′-bipyridine) have been synthesized and determined by single crystal X-ray diffraction. Complex 1 is a 1-D helical chain with seven-coordinated praseodymium centers. Complex 2 forms 1-D chain-like molecular structure containing two crystallographically unique dysprosium centers, the Dy¹ center is seven-coordinated while Dy² is eight-coordinated. The isomorphous complexes 3 and 4 exhibit an unprecedented 1-D chain-like polymeric structure through hydroxyl oxygen atoms of bridging Onic²⁻ anions linking up the neighboring central ions, and there exist three types of 6-OHnicH ligands in the structural unit which is rare for lanthanide carboxylate complexes. The photophysical properties of these complexes were studied using ultraviolet absorption spectra, fluorescence excitation and emission spectra.     

Syntheses,crystal structures,and magnetic and luminescent properties of a series of lanthanide coordination polymers with chelidamic acid ligand

A series of lanthanide(III) complexes with chelidamic acid ligand, [Ln(C₇H₂NO₅)·3H₂O]_n·nH₂O (Ln = La (1), Y (2), Sm (3), and Nd (4)), [Gd₂(C₇H₂NO₅)₃·4H₂O]_n·2nH₂O (5) and [Ce(C₇H₂NO₅)·1.5H₂O]_n (6), have been synthesized by hydrothermal method and structurally characterized by single-crystal X-ray diffraction. Complexes 1–4 are isostructural and possess 2D framework. Complex 5 contains two different Gd(III) ions linked through carboxylate group to form a 2D framework. Complex 6 exhibits a (4⁴) topology 2D network. The variable-temperature magnetic properties of 3 and 5 have been investigated. Furthermore, the photoluminescent properties of 1, 2, 3, and 5 at room temperature were also studied.     

Mononuclear Cu and dinuclear Cu–Ln complexes of benzimidazole based ligands including N and O donors: Syntheses,characterization, X-ray molecular structures and magnetic properties

The synthesis of two mononuclear precursor copper complexes, [(HL²)₂Cu], 1, and [(HL³)₂Cu]·H₂O, 2, and three dinuclear Cu–Ln complexes, [(HL¹)₂Cu(CH₃CN)₂Gd(NO₃)₃], 3, [(HL³)₂CuGd(NO₃)₃]·2(H₂O), 4, and [(HL³)₂CuTb(NO₃)₃]·2(H₂O), 5, based on the ligands H₂L¹ (4-bromo-2-[1-(5-bromo-2-hydroxy-3-methoxybenzyl)-1H-benzimidazol-2-yl]-6-methoxyphenol), H₂L² (2-(1H-benzimidazol-2-yl)-4-bromo-6-methoxyphenol) and H₂L³ (2-(1H-benzimidazol-2-yl)-6-methoxyphenol) are described in this contribution. The X-ray crystal structures of H₂L², 1, 3, 4, and 5 have been solved. The novel ligand H₂L² crystallizes with two independent molecules in the asymmetric unit; several intermolecular hydrogen contacts connect alternate independent H₂L² molecules into chains developing along c. In complex 1, two (HL²)⁻ ligands chelate the copper ion through their imidazolyl nitrogen and phenoxo oxygen atoms, in a relative head to tail arrangement. The molecular structure of 3 is similar to those of the previously reported Cu–Ln complexes of H₂L¹. In the isostructural complexes 4 and 5, two HL³ ligands sandwich one Cu²⁺ ion through their N,O sites and one Ln³⁺ ion through their O₂ site, implying a relative head to head arrangement, at variance with the relative head to tail arrangement of HL² in the mononuclear copper precursor 1. The magnetic properties of 1, 3, 4, and 5 have been investigated. Extended intermolecular antiferromagnetic interactions operate in complex 1 ((J_Chain = −0.8(1) cm⁻¹). Ferromagnetic interactions between Gd (S = 7/2) and Cu (S = 1/2) centers operate in complexes 3 and 4, leading to an S = 4 ground state (J_CuGd = 7.2(2) cm⁻¹ for 3 and J_CuGd = 6.5(2) cm⁻¹ for 4). Depopulation of the Tb Stark levels, preclude obtaining reliable information on the presence and sign of the Cu–Tb interaction in 5. These new complexes are complementary to those previously reported: the Cu–O₂–Gd core is planar while deformations are borne by the ligands at variance with previous examples where the constraints were located at the Cu–O₂–Gd core. The presence of two independent ligands in the Cu,Gd coordination spheres confers a degree of freedom greater than that allowed by a unique tetradentate ligand. As a result, the strength of the magnetic interaction is not solely related to the dihedral angle between the CuOO and GdOO planes in the central core.     

A series of novel metal-ferrocenedicarboxylate coordination polymers: crystal structures, magnetic and luminescence properties

Novel two-dimensional layered lanthanide(III)-ferrocenedicarboxylate coordination polymers {[M(η²-O₂CFcCO₂-η²)(μ₂-η²-O₂CFcCO₂-η²-μ₂)_0.5(H₂O)₂]·mH₂O}_n (Fc=(η⁵-C₅H₄)Fe(η⁵-C₅H₄), M=Tb³⁺, m=2, 1; M=Eu³⁺, m=2, 2; M=Y³⁺, m=1, 3) with trapezium-shaped units and one-dimensional wave-shaped Cd(II)-ferrocenedicarboxylate polymer {[Cd(η²-O₂CFcCO₂-η²)(H₂O)₃]·4H₂O}_n (4) have been prepared and structurally characterized by single crystal diffraction. In polymers 1-3, each central metal ion (Tb(III), or Eu(III) or Y(III)) is located in a pseudo-capped-tetragonal prism coordination geometry, and ferrocenedicarboxylate anion ligands have two coordination modes (bidentate-chelating mode and tridentate-bridging mode). The magnetic behaviors for 1 and 2 are studied in the temperature range of 5.0-300 K. The results show that the paramagnetic behavior of 2 is mainly due to the effective spin-orbital coupling between the ground and excited states through the Zeeman perturbation, and the weak magnetic interaction between Eu³⁺ centers can be observed. In addition, compared with sodium ferrocenedicarboxylate, the fluorescent intensities of the polymers 1-4 are enhanced in the solid state.     

Triangular Ni2Ln and Ni2Y complexes derived from di-2-pyridyl ketone: Synthesis, structures and magnetic properties

The synthetic investigation of the Ni^II/M(NO₃)₃·6H₂O/di-2-pyridyl ketone [(py)₂CO] tertiary reaction system in EtOH has yielded triangular Ni₂M cationic complexes (M = lanthanide, Y). The reaction between Ln(NO₃)₃·6H₂O, Ni(ClO₄)₂·6H₂O, (py)₂CO and base (1:3:3:3) in EtOH under gentle heating gave the isostructural complexes [Ni₂Ln{(py)₂C(OEt)(O)}₃{(py)₂C(OH)(O)}(NO₃)(H₂O)](ClO₄)₂ (Ln = Gd, 2; Ln = Tb, 3) in high yields. The ligands (py)₂C(OEt)(O)⁻ and (py)₂C(OH)(O)⁻ are the monoanions of the hemiketal and gem-diol derivatives of (py)₂CO, respectively, formed in situ in the presence of the metal ions. The cations of 2 and 3 consist of one 8-coordinate Ln^III and two distorted octahedral Ni^II atoms in an essentially isosceles, triangular arrangement capped by a central μ₃-Ο⁻ atom of the unique 3.3011 (Harris notation) (py)₂C(OH)(O)⁻ ligand. Each metal-metal edge is bridged by the deprotonated O atom of one 2.2011 (py)₂C(OEt)(O)⁻ ligand. The isostructural complexes [Ni₂M{(py)₂C(OEt)(O)}₄(NO₃)(H₂O)]₂[M(NO₃)₅](ClO₄)₂ (M = Y, 4 ; M = Tb, 5 ; M = Dy, 6) were prepared by the 1:1 reaction of the mononuclear “metalloligand” [Ni(O₂CMe){(py)₂CO}{(py)₂C(OH)₂}](ClO₄) (1) and M(NO₃)₃·6H₂O in EtOH under mild heating in moderate to good yields. The structures of the dications of 4-6 are similar to those in 2 and 3, the only difference being the replacement of the unique 3.3011 (py)₂C(OH)(O)⁻ ligand of the latter by one 3.3011 (py)₂C(OEt)(O)⁻ group in the former. The Y^III, Tb^III and Dy^III atoms in [M(NO₃)₅]²⁻ are coordinated by five bidentate chelating nitrato groups. Characteristic IR bands of the complexes are discussed in terms of the known structures and the coordination modes of the ligands. Variable temperature, solid-state direct current magnetic susceptibility and magnetization studies were carried out on dried samples of 2-4. The data indicate ferromagnetic Ni?Ni and Ni?Gd exchange interactions, and an S_T = 11/2 ground state for 2. Complex 3 is characterized by a high-spin ground state while the ferromagnetic Ni?Ni interaction for 2 is independently supported by the study of 4. No out-of-phase, alternating current susceptibility signals have been detected for 3 that would be indicative of SMM behavior.     

New 3d–4f supramolecular systems constructed by [Fe(bipy)(CN)4] and partially blocked lanthanide cations

The reaction of acetonitrile (1–5) and mixed acetonitrile/water 1:1 (6–9) solutions containing the cyanide-bearing [Fe(bipy)(CN)₄]⁻ building block (bipy = 2,2′-bipyridine) and the partially blocked [Ln(bpym)]³⁺ cation (Ln = lanthanide trivalent cation and bpym = 2,2′-bipyrimidine) has afforded two new families of 3d–4f supramolecular assemblies of formula [Ln(bpym)(NO₃)₂(H₂O)₃][Fe(bipy)(CN)₄] · H₂O · CH₃CN [Ln = Sm (1), Gd (2), Tb (3), Dy (4) and Ho (5)] and [Ln(bpym)(NO₃)₂(H₂O)₄][Fe(bipy)(CN)₄] [Ln = Pr (6), Nd (7), Sm (8), Gd (9)]. They crystallize in the P2₁/c (1–5) and P2/c (6–9) space groups and their structures are made up of [Fe(bipy)(CN)₄]⁻ anions (1–9) and [Ln(bpym)(NO₃)₂(H₂O)_n]⁺ cations [n = 3 (1–5) and 4 (6–9)] with uncoordinated water and acetonitrile molecules (1–5) which are interlinked through an extensive network of hydrogen bonds and π–π stacking into three-dimensional motifs. Both families have in common the occurrence of the low-spin iron(III) unit [Fe(bipy)(CN)₄]⁻ where two bipy–nitrogen and four cyanide–carbon atoms build a somewhat distorted octahedral surrounding around the iron atom [Fe–N = 1.980(3)–1.988(3) Å (1–5) and 1.988(2)–1.992(2) Å (6–9); Fe–C = 1.904(5)–1.952(4) Å (1–5) and 1.911(2)–1.948(3) Å (6–9)]. The main structural difference between both families concerns the environment of the lanthanide atom which is nine- (1–5)/10-coordinated (6–9) with a chelating bpym, two bidentate nitrate and three (1–5)/four (6–9) water molecules building distorted monocapped (1–5)/bicapped (6–9) square antiprisms. This different lanthanide environment is at the origin of the different hydrogen bonding pattern of the two families of compounds.     

Mono and dinuclear half-sandwich platinum group metal complexes bearing pyrazolyl-pyrimidine ligands: Syntheses and structural studies

Reactions of 0.5 eq. of the dinuclear complexes [(η⁶-arene)Ru(μ-Cl)Cl]₂ (arene = η⁶-C₆H₆, η⁶-p-ⁱPrC₆H₄Me) and [(Cp∗)M(μ-Cl)Cl]₂ (M = Rh, Ir; Cp∗ = η⁵-C₅Me₅) with 4,6-disubstituted pyrazolyl-pyrimidine ligands (L) viz. 4,6-bis(pyrazolyl)pyrimidine (L1), 4,6-bis(3-methyl-pyrazolyl)pyrimidine (L2), 4,6-bis(3,5-dimethyl-pyrazolyl)pyrimidine (L3) lead to the formation of the cationic mononuclear complexes [(η⁶-C₆H₆)Ru(L)Cl]⁺ (L = L1, 1; L2, 2; L3, 3), [(η⁶-p-ⁱPrC₆H₄Me)Ru(L)Cl]⁺ (L = L1, 4; L2, 5; L3, 6), [(Cp∗)Rh(L)Cl]⁺ (L = L1, 7; L2, 8; L3, 9) and [(Cp∗)Ir(L)Cl]⁺ (L = L1, 10; L2, 11; L3, 12), while reactions with 1.0 eq. of the dinuclear complexes [(η⁶-arene)Ru(μ-Cl)Cl]₂ and [(Cp∗)M(μ-Cl)Cl]₂ give rise to the dicationic dinuclear complexes [{(η⁶-C₆H₆)RuCl}₂(L)]²⁺ (L = L1, 13; L2, 14; L3, 15), [{(η⁶-p-ⁱPrC₆H₄Me)RuCl}₂(L)]²⁺ (L = L1, 16; L2, 17; L3, 18), [{(Cp∗)RhCl}₂(L)]²⁺ (L = L1, 19; L2, 20; L3, 21) and [{(Cp∗)IrCl}₂(L)]²⁺ (L = L1 22; L2, 23; L3 24). The molecular structures of [3]PF₆, [6]PF₆, [7]PF₆ and [18](PF₆)₂ have been established by single crystal X-ray structure analysis.     

New calсium β-diketonate complexes: The monomeric complexes [Ca(PhCOCHCOCF3)2(15-crown-5)], [Ca(AdCOCHCOCF3)2(15-crown-5)] and the binuclear hydrated complex [{Ca(adtfa)(18-crown-6)(H2O)}{Ca(adtfa)3(H2O)}(EtOH)]. Synthesis, characterization and crystal structure

The preparation of the Ca-β-diketonate complexes with crown-ethers, [Ca(btfa)₂(15-crown-5)] (1), [Ca(adtfa)₂(15-crown-5)] (2), [Ca(adtfa)₂(15-crown-5)](C₆H₅CH₃)_0.5 (3) and [{Ca(adtfa)(18-crown-6)(H₂O)}{Ca(adtfa)₃(H₂O)}(EtOH)] (4) (btfa = 1,1,1-trifluoro-4-phenyl-butanedionato-2,4; adtfa = 1,1,1-trifluoro-4-(1-adamantyl)butanedionato-2,4; 15-crown-5 = 1,4,7,10,13-pentaoxacyclopentadecane; 18-crown-6 = 1,4,7,10,13,16-hexaoxacyclooctadecane), is described. Complex 1 has been prepared from the reaction of metallic Ca with 2 eq. of Hbtfa and 1 eq. of 15-crown-5 in toluene; complex 2 has been prepared from the reaction of metallic Ca with 2 eq. of Hadtfa and 1 eq. of 15-crown-5 in ethanol. The solvated complex 3 was obtained by cooling of a toluene-hexane solution of 2. The hydrated complex 4 was prepared from the reaction of metallic Ca with 2 eq. of Hadtfa and 1 eq. of 18-crown-6, followed by addition of excess H₂O to the resulting reaction mixture. The all complexes were characterized by elemental analyses, IR-spectroscopy, NMR-spectroscopy, single-crystal X-ray diffraction methods, DSC and TGA. A single-crystal X-ray study of 1 and 3 has show that complexes 1 and 3 are monomeric and contain the calcium atom bonded with two β-diketonate ligands and one molecule of crown-ether. Complex 4, as shown by X-ray analyses, is an ion-paired solvated adduct, containing the cation {Ca(adtfa)(18-crown-6)(H₂O)}⁺ and the anion {Ca(adtfa)₃(H₂O)}⁻. The monomeric complexes 1-3 are volatile and thermally stable in the temperature range 100-260 °C. Complex 4 undergoes decomposition above 110 °C with consecutive loss of ethanol, H₂O, 18-crown-6 and some evaporization of 4.     

Versatility in the mode of coordination {(N), (N,O), (C,N) or (C,N,O)} of [(η-C5H5)Fe{(η-C5H4)-CHN-(C6H4-2OH)}] to palladium(II)

The study of the reactivity of the ferrocenyliminoalcohol [(η⁵-C₅H₅)Fe{(η⁵-C₅H₄)-CHN-(C₆H₄-2OH)}] (1b) with Na₂[PdCl₄] or Pd(OAc)₂ has allowed the isolation and characterization of the heterotrimetallic complexes: trans-[Pd{(η⁵-C₅H₅)Fe[(η⁵-C₅H₄)-CHN-(C₆H₄-2OH)]}₂Cl₂] (2b), [Pd{[(η⁵-C₅H₃)-CHN-(C₆H₄-2O)]Fe(η⁵-C₅H₅)}{(η⁵-C₅H₅)Fe[(η⁵-C₅H₄)-CHN-(C₆H₄-2OH)]}] (3b) and trans-[Pd{(η⁵-C₅H₅)Fe[(η⁵-C₅H₄)-CHN-(C₆H₄-2O)]}₂] (4b). Ligand 1b acts as a (N) (in 2b) or a (N,O)⁻ (in 4b) ligand; while in 3b the two units of the iminoalcohol exhibit simultaneously different modes of binding {(N) and [C(sp², ferrocene),N,O]²⁻}. The crystal structures of 2b · 3H₂O and 3b · 1/2CHCl₃ are also reported and confirm the mode of binding of the ligand in these compounds. The relative importance of the factors affecting the preferential formation of products (2b-4b) is also discussed. The study of the reactivity of 3b with PPh₃ has enabled the obtention of the cyclopalladated complexes [Pd{[(η⁵-C₅H₃)-CHN-(C₆H₄-2O)]Fe(η⁵- C₅H₅)}(PPh₃)] (6b) and [Pd{[(η⁵-C₅H₃)-CHN-(C₆H₄-2OH)]Fe(η⁵-C₅H₅)}Cl(PPh₃)] (7b), in which 1b behaves as a [C(sp², ferrocene),N,O]²⁻ (in 6b) or [C(sp², ferrocene),N]⁻ (in 7b) ligand. Treatment of 3b with MeO₂C-CC-CO₂Me produces [Pd{[(MeO₂C-CC-CO₂Me)₂(η⁵-C₅H₃)-CHN-(C₆H₄-2O)]Fe(η⁵-C₅H₅)}] (8b), that arises from the bis(insertion) of the alkyne into the σ[Pd-C(sp², ferrocene)] bond. The comparison of the results obtained for 1b and [C₆H₅-CHN-(C₆H₄-2OH)] (1a) has allowed to establish the influence of the substituents on the imine carbon on their reactivity in front of palladium(II) as well as on the lability of the Pd-ligands bond. ⁵⁷Fe Mössbauer studies of 2b-4b and 6b provide conclusive evidence of the effect induced by the mode of binding of 1b on the environment of the iron(II).     

Dinuclear double-helical cobalt complexes with two-armed terdentate ligands: Synthesis,structure and physical properties

Three ligands with flexible bis-terdentate coordination sites, di(2-pyridylcarbaldehyde)-6,6′-dicarboxylic acid hydrazone-2,2′-bipyridine (H₂L¹), di(2-acetylpyridyl)-6,6′-dicarboxylic acid hydrazone-2,2′-bipyridine (H₂L²) and di(2-pyridylketone)-6,6′-dicarboxylic acid hydrazone-2,2′-bipyridine (H₂L³) have been easily prepared. Dinuclear double-stranded helicates Co₂(L¹)₂(ClO₄)₂(C₂H₅OH)₂(H₂O)₂ (1), Co₂(HL²)(L²)(ClO₄)₃(C₂H₅OH)₂(H₂O)₂ (2) and Co₂(HL³)(L³)(ClO₄)₃(H₂O)₄ (3) based on the ligands, H₂L^1–3, respectively, have been obtained via self-assembly, their structures were determined by FT-IR, Elemental Analysis, ESI-MS and X-ray diffraction method.     

Coordination and extraction studies of an unexplored bi-functional ligand,carbamoyl methyl pyrazole (CMPz) with uranium(VI), lanthanum(III) and cerium(III) nitrates

The bi-functional carbamoyl methyl pyrazole ligands, C₅H₇N₂CH₂CONBu₂ (L₁), C₅H₇N₂CH₂CONⁱBu₂ (L₂), C₃H₃N₂CH₂CONBu₂ (L₃), C₃H₃N₂CH₂CONⁱBu₂ (L₄) and C₅H₇N₂CH₂CON(C₈H₁₇)₂ (L₅) were synthesized and characterized by spectroscopic and elemental analysis methods. The selected coordination chemistry of L₁ to L₄ with [UO₂(NO₃)₂ · 6H₂O], [La(NO₃)₃ · 6H₂O] and [Ce(NO₃)₃ · 6H₂O] has been evaluated. Structures for the compounds [UO₂(NO₃)₂ C₅H₇N₂CH₂CONBu₂] (6) [UO₂(NO₃)₂ C₅H₇N₂CH₂CONⁱBu₂] (7) and [Ce(NO₃)₃{C₃H₃N₂CH₂CONⁱBu₂}₂] (11) have been determined by single crystal X-ray diffraction methods. Preliminary extraction studies of the ligand L₅ with U(VI) and Pu(IV) in tracer level showed an appreciable extraction for U(VI) and Pu(IV) up to 10 M HNO₃ but not for Am(III). Thermal studies of the compounds 6 and 7 in air revealed that the ligands can be destroyed completely on incineration.     

Formation of 5-phenyl-1,2-dithiole-3-thione from molybdenum dithiopropiolato complexes

Molybdenum dithiopropiolato complexes, [(η⁵-C₅R₄R^′)Mo(CO)₂(η²-S₂CCCPh)] (R=H, R^′=Me 1a, R=R^′=H 1b; R=R^′=Me 1c) react with trimethylamine-N-oxide (TMNO · 2H₂O) under mild thermolysis to form 5-phenyl-1,2-dithiole-3-thione (2). The reaction proceeds through the formation of the oxo-complexes, [(η⁵-C₅R₄R^′)Mo(O)(η³-S₂CCCPh)] (R=H, R^′=Me 3a, R=R^′=H 3b; R=R^′=Me 3c). Direct reaction of 3a-c with TMNO · 2H₂O under thermolysis also results in formation of 2.     

Syntheses,supramolecular structures and properties of six coordination complexes based on 5-sulfosalicylic acid and bipyridyl-like chelates

Six new complexes constructed by 5-sulfosalicylic acid and bipyridyl-like ligands (2,2′-bipy and 1,10-phen), namely [Cu₄(OH)₂(ssal)₂(phen)₄ · 7H₂O] (1), [Cu₄(OH)₂(ssal)₂(bipy)₄ · 2H₂O] (2), [Cd(Hssal)(bipy)] (3), [Cd(HL)₂(phen)₂] (4), [Cr(ssal)(bipy)(H₂O)₂ · 2H₂O] (5) and [Cr(ssal)(phen)₂] (6) (H₃ssal = 5-sulfosalicylic acid, H₂L = p-hydroxybenzenesulfonic acid, bipy = 2,2′-bipy, phen = 1,10-phen) were prepared under hydrothermal conditions and their structures were determined by single-crystal X-ray diffraction. Complexes 1 and 2 are both tetranuclear copper complexes with a stepped topology. In complex 3, a new coordination mode of the Hssal²⁻ group is reported in this work. During the synthetic process of complex 4, in situ decarboxylation of 5-sulfosalicylic acid into p-hydroxybenzenesulfonic acid is involved. Two chromium 5-sulfosalicylates (5 and 6) are reported for the first time. These new complexes display different supramolecular structures by O–H?O, C–H?O hydrogen bonds as well as π?π, C–H?π and O?π interactions. The results of magnetic determination show that ferromagnetic interactions exist in complex 1, however, antiferromagnetic interactions exist in 2.     

Synthesis, characterization and crystal structures of a new 2-ferrocenylnaphthoxazole and its mercurated derivatives

A new ferrocenylnaphthoxazole [(η⁵-C₅H₅)Fe{(η⁵-C₅H₄)C(O)N(C₁₀H₆)}] (1) was synthesized under mild conditions. Two mercurated derivatives: ortho-mercurated product [HgCl{(η⁵-C₅H₅)Fe[(η⁵-C₅H₃)C(O)N(C₁₀H₆)]}] (2) and the product mercurated on the unsubstituted Cp ring [HgCl{(η⁵-C₅H₄)Fe[(η⁵-C₅H₄)C(O)N(C₁₀H₆)]}] (3) were obtained by the reaction of 1 with mercuric acetate. All the new compounds 1, 2 and 3 were characterized by elemental analyses, IR, NMR, MS spectra and X-ray crystal structure analysis. The crystal structure of 1 extended into a 2D supramolecular network through the intermolecular π-π stacking interaction between the Cp ring and naphthoxazole ring. In the crystal of 2, there exist bridged Cl-Hg bonds, CH(Cp) ? Cl and CH? Hg hydrogen bonds, π-π stacking interactions, which facilitate construction of this complex into a 3D supramolecular structure.     

Carbonylation of four-membered ruthenium and osmium metallacycles incorporating an orthometallated phenolic function: New acylruthenium and arylosmium complexes

The solution reaction of Ru(QL¹)(PPh₃)₂(CO)Cl (3) and Os(QL¹)(PPh₃)₂(CO)Br (4) with carbon monoxide at one atmosphere pressure has respectively afforded the orange acylruthenium system Ru(QL²)(PPh₃)₂(CO)Cl (5) and the yellow arylosmium dicarbonyl system Os(QL³)(PPh₃)₂(CO)₂Br (6) in excellent yields. (QL¹ is C₆H₂O-2-CHNHC₆H₄Q(p)-3-Me-5, QL² is C₆H₂(CO-1)O-2-CHNHC₆H₄Q(p)-3-Me-5 and QL³ is C₆H₂OH-2-CHNC₆H₄Q(p)-3-Me-5 and Q is Me, OMe and Cl.) It is proposed that in the case of 3 a dicarbonyl complex similar to 6 is formed as an intermediate which rapidly undergoes aryl migration with concomitant phenolato coordination furnishing 5. The stability of 6 is consistent with the greatly diminished ability of osmium in promotion of migratory reactions. In the reaction 4 → 6 the Os-O(phenolato) bond is cleaved and the Schiff base moiety undergoes iminium-phenolato → imine-phenol tautomerization. The observed cis geometry of 6 may arise by a concerted route involving edge displacement of the halide ligand. The crystal and molecular structure of 5(Q = Cl) has revealed the presence of a distorted octahedral RuC₂P₂OCl coordination sphere and a highly planar acyl chelate ring characterized by a Ru-C distance of 2.013(4) Å. In the hydrogen bonded zwitterionic iminium-phenolato ring the N ? O distance is 2.561(6) Å. The acyl complexes of type 5 display an MLCT band near 500 nm which is absent in 6. The Schiff base CN stretch in 5 (∼1630 cm⁻¹) is significantly higher than that in 6 (∼1600 cm⁻¹) which displays two strong CO stretches near 2020 and 1940 cm⁻¹ (cis-Os(CO)₂ configuration). A single ³¹P NMR signal occurs in both 5 and 6 near 37 and −6 ppm, respectively (trans-M(PPh₃)₂ configuration). The voltammetric reduction potentials of the M^III/M^II couple is observed near 1.0 and 0.8 V vs. SCE in 5 and 6, respectively. Both are significantly higher than those in parent complexes (3 and 4) due to stabilization of the bivalent state upon carbonylation.     

Syntheses and characterizations of nine coordination polymers of transition metals with carboxylate anions and bis(imidazole) ligands

Nine new compounds, namely [CuL1(biim-6)] · H₂O (1), [ZnL1(biim-6)] · H₂O (2), [MnL1(biim-6)] · H₂O (3), [MnL1(biim-4)] (4), [Co₂(L2)₂(biim-5)₃ · 6H₂O] · 8H₂O (5), [ZnL3(biim-6)] (6), [ZnL3(biim-5)] (7), [CdL3(biim-5) · 1.5H₂O] · 0.5H₂O (8) and [CdL4(biim-6) · 2H₂O] (9) [where L1 = oxalate anion, L2 = fumarate anion, L3 = phthalate anion, L4 = p-phthalate anion, biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole), biim-5 = 1,1′-(1,5-pentanedidyl)bis(imidazole) and biim-6 = 1,1′-(1,6-hexanedidyl)bis(imidazole)] were successfully synthesized. Compounds 1–3 are isostructural, and display 2D polymeric structures. Compound 4 shows a threefold interpenetrating diamondoid framework. In compound 5, the anions act as counterions, and the metal cations are bridged by bis(imidazole) ligands to form 1D polymeric chains. Compounds 6–9 show 2D polymeric structures. The magnetic properties for 1, 3 and 4 and luminescent properties for 2 and 6–9 are discussed. Thermogravimetric analyses (TGA) for these compounds are also discussed.     

Synthetic and X-ray diffraction studies of borosiloxane cages [R′Si(ORBO)3SiR′] and the adducts of [BuSi{O(PhB)O}3SiBu] with pyridine or N,N,N′,N′-tetramethylethylenediamine

Eleven borosiloxane [R′Si(ORBO)₃SiR′] compounds where R′ = Bu^t and R = Ph (1), 4-PhC₆H₄ (2), 4-Bu^tC₆H₄ (3), 3-NO₂C₆H₄ (4), 4-CH(O)C₆H₄ (5), CpFeC₅H₄ (6), 4-C(O)CH₃C₆H₄ (7), 4-ClC₆H₄ (8), 2,4-F₂C₆H₃ (9), and R′ = cyclo-C₆H₁₁ and R = Ph (10), and 4-BrC₆H₄ (11) have been synthesized and characterized by spectroscopic (IR, NMR), mass spectrometric and, for compounds where R′ = Bu^t and R = 4-PhC₆H₄ (2), 4-Bu^tC₆H₄ (3), 3-NO₂C₆H₄ (4), CpFeC₅H₄ (6) and 2,4-F₂C₆H₃ (9), X-ray diffraction studies. These compounds contain trigonal planar RBO₂ and tetrahedral R′SiO₃ units located around 11-atom “spherical” Si₂O₆B₃ cores. The dimensions of the Si₂O₆B₃ cores in compounds 2, 3, 4, 6 and 9 are remarkably similar. The reaction between [Bu^tSi{O(PhB)O}₃SiBu^t] (1), and excess pyridine yields the 1:1 adduct [Bu^tSi{O(PhB)O}SiBu^t]. NC₅H₅ (12) while the reaction between 1 and N,N,N′,N′-tetramethylethylenediamine in equimolar amounts affords a 2:1 borosiloxane:amine adduct [Bu^tSi{O(PhB)O}₃SiBu^t]₂ · Me₂NCH₂CH₂NMe₂ (13). Compounds 12 and 13 were characterised with IR and (¹H, ¹³C and¹¹B) NMR spectroscopies and the structure of the pyridine complex 12 was determined with X-ray techniques.     

Cobalt bis(dicarbollide) ions functionalized by CMPO-like groups attached to boron by short bonds; efficient extraction agents for separation of trivalent f-block elements from highly acidic nuclear waste

New boron substituted cobalta bis(dicarbollide)(1-) ion (1) derivatives of formula [(8,8′-(RPhP(O)(CH₂)nC(O)N) < (1,2-C₂B₉H₁₀)₂-3,3′-Co]⁻ (R = Ph or C₈H₁₇, n = 1, 3a, 3b; R = Ph, n = 2, 3c), [(8-(Ph₂P(O)CH₂C(O)NR)(1,2-C₂B₉H₁₀))(1′,2′-C₂B₉H₁₁)-3,3′-Co]⁻ (R = H, C₂H₅, CH₂C₆H₅, 5a-c) and [(8-(²RPhP(O)CH₂C(O)N(¹R)CH₂-1,2-C₂B₉H₁₀))(8′-CH₃O-1′,2′-C₂B₉H₁₀)-3,3′-Co]⁻ (¹R = Benzyl, ²R = Ph or C₈H₁₇, 7a,b) were prepared with the aim to develop a new class of efficient extraction agents for partitioning of polyvalent f-block elements, i.e. lanthanides and actinides from high-level activity nuclear waste. The anionic ligands were characterized by multinuclear NMR spectroscopy and MS, the structures of Cs3a and the calcium complex of 7a were determined by X-ray diffraction analysis. The crystallographic study of the Cs3a proved a formation of linear chains in the structure, where the metal cation is coordinated by oxygen atoms of the CMPO terminal groups. The X-ray structure of the Ca²⁺ complex of the ionic ligand 7a proved a 1:3 metal to ligand ratio. Presented also is the X-ray structure of the starting ammonium compound 6 used in the synthesis of 7a and 7b. With exception of 5c, these anionic ligands are of high extraction efficiency, the highest being found for 7a in low polar solvent mixture hexyl methyl ketone-dodecane 1:1. These properties qualify some of these derivatives for possible technological applications.     

A series of three-dimensional coordination polymers with general formula [{Ln(H2O)n}{Re6Te8(CN)6}] · xH2O (Ln = Eu,Gd, Tb,Dy, Ho,Er, Tm,Yb; n = 3, 4, x = 0, 2.5)

A series of new compounds containing rare earth cations (Eu to Yb) and paramagnetic cluster anion [Re₆Te₈(CN)₆]³⁻ was prepared and investigated. The X-ray structural analyses have revealed that the compounds [{Ln(H₂O)₄}{Re₆Te₈(CN)₆}] · 2.5H₂O; Ln = Eu (1), Tb (3), Dy (4), Ho (5), Er (6), Tm (7), [{Gd(H₂O)₃}{Re₆Te₈(CN)₆}] · 2.5H₂O (2) and [{Yb(H₂O)₄}{Re₆Te₈(CN)₆}] (8) are three-dimensional polymers based on Re–CN–Ln interactions. Measurements of magnetic susceptibility for 2 and 5 showed that effective magnetic moment (at 300 K) was 8.13 μ_B for compound 2 and 10.79 μ_B for compound 5 with weak antiferromagnetic ordering appeared at low temperatures.     

Infinite chains constructed from flexible bis(benzimidazole)-based ligands

Two neutral ligands, L¹ · 2H₂O and L² · H₂O, and seven complexes, [Cu(pmb)₂(L¹)] (1), [Cu(pmb)₂(L²)] (2), [Cu(Ac)₂(L²)] · 4H₂O (3), [Cu(4-aba)₂(L²)] (4), [Ag(4-ts)(L¹)(H₂O)] (5), [Ag₂(epes)₂(L¹)] · 2H₂O (6), [Ag(1,5-nds)_0.5(L²)] · 0.5C₂H₅OH · H₂O (7) [where L¹ = 1,1′-(1,4-butanediyl)bis(2-methylbenzimidazole); L² = 1,1′-(1,4-butanediyl)bis(2-ethylbenzimidazole), pmb = p-methoxybenzoate anion; Ac = acetate anion; 4-aba = 4-aminobenzoate anion; 4-ts = p-toluenesulfonate anion; epes = N-(2-hydroxyethyl)piperazine-N′-(2-ethanesulfonate) anion; 1,5-nds = 1,5-naphthalenedisulfonate anion], have been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. The L¹ and L² ligands in compounds 1–7 act as bridging ligands, linking metal ions into chain structures. The chains in compounds 3, 4 and 6 interlace with each other by hydrogen bonds to generate 3D supramolecular structures. In compound 5, π–π interactions between adjacent L¹ ligands hold the chains to a supramolecular layer. In compound 7, the sulfonate anions act as counterions in the framework. The thermal stabilities of 3, 6 and 7, and the luminescent properties for 5–7 in the solid states are also discussed.