Substitution of CO Ligand by P(OPh)3 in Radical Cations of the Cymantrene Family: Relationships of Substitution Rates to E1/2 Values and Carbonyl IR Frequencies

A series of piano-stool complexes of the cymantrene family (cymantrene = Mn(η⁵-C₅H₅)(CO)₃, 1) undergoes facile replacement of a carbonyl ligand by P(OPh)₃ when oxidized by one-electron in CH₂Cl₂/[NBu₄][B(C₆F₅)₄]. Data on the previously characterized complexes 1, Mn(η⁵-C₅H₄NH₂)(CO)₃ (3) and Mn(η⁵-C₅Me₅)(CO)₃ (6) have been supplemented by cyclic voltammetry (CV) and IR spectroscopy on Mn(η⁵-C₅H₄Me)(CO)₃ (2), Mn(η⁵-C₅H₄I)(CO)₃ (4), and Mn(η⁵-C₅H₄C(O)H)(CO)₃ (5). The substitution rates, determined by digital simulations of CV scans, ranged from 4 M^?1 s^?1 for 6 ⁺ to 3 × 10⁵ M^?1 s^?1 for 5 ⁺. In general, a more strongly donating cyclopentadienyl substituent slows down the CO substitution rate. For mono-cyclopentadienyl substituted complexes, the logarithm of k_sub is shown to increase linearly with either the weighted average of the CO stretching frequencies or the E_1/2 value of the redox process. An exception to this generalization is the amine-substituted complex 3, for which the CO-substitution rate is higher than predicted by its E_1/2 potential. The substitution rate of the pentamethylated Cp complex 6 ⁺ is slowed by about an order of magnitude owing to steric effects. The efficacy of this method to predict the CO-substitution rate of a cymantrene-tagged molecule was tested with a cymamtrene-derivatized diarylethene complex, 7. The measured P(OPh)₃-for-CO substitution rate of 3.7 × 10² M^?1 s^?1 for 7 ⁺ was very close to that predicted by the E_1/2 value of 7. A ligand electronic parameter, E_L, of 0.62 was determined for the triphenylphosphite ligand. These studies build on the previous CO substitution-rate analyses by Sweigart and others.     

Second-Order NLO Active Heterotrimetallic Schiff Base Metallopolymer

The new ionic heterotrimetallic unsymmetrically-substituted Schiff base complex [Ni{(η ⁵-Cp)Fe(η ⁵-C₅H₄)-C(=O)CH=C(4-HO-C₆H₄)NCH₂CH₂N=CH-(2-O-(η ⁶-C₆H₄)Ru(η ⁵-Cp*)}][PF₆] (3; Cp = C₅H₅ and Cp* = C₅(CH₃)₅) was prepared in 86% yield by a one-pot procedure by mixing equimolar amounts of 4-hydroxyphenyl functionalized ferrocenylenaminone 1, the organometallic aldehyde [(η ⁵-Cp*)Ru(η ⁶-2-HO-C₆H₄CHO)][PF₆] (2) and nickel(II) acetate tetrahydrate in refluxing ethanol for 2 h. Its corresponding side-chain metallopolymer 4 was synthesized by reacting the organometallic-inorganic hybrid 3 with polyacrylic acid (DP = 25) in DMF at 110 °C for 48 h with an equimolar quantity of N,N′-dicyclohexylcarbodiimide and a catalytic amount of 4-dimethylaminopyridine. The new complex 3 was characterized by FT-IR and multidimensional NMR spectroscopy, elemental analysis and mass spectrometry. Single crystal X-ray diffraction analysis of 3 showed that the ferrocenyl and [(η ⁵-Cp*)Ru]⁺ units exhibit an anti-conformation and are almost coplanar with the unsymmetrical Schiff base complex fragment, while the 4-HO-C₆H₄ plane is almost perpendicular. The four-coordinate Ni^II metal ion adopts a square planar geometry, with two nitrogen and two oxygen donor atoms that are mutually trans. Size-Exclusion Chromatography established that metallopolymer 4 is formed of approximately three pendant ionic trimetallic units, while Differential Scanning Calorimetry and Thermal Gravimetric Analysis indicated that 3 and 4 are thermally stable with decomposition temperatures that exceed or border to 250 °C. Harmonic Light Scattering measurements at 1.91 µm incident wavelength showed that compounds 3 and 4 exhibit rather high second-order nonlinear responses, with hyperpolarizability β _1.91 values strongly increasing on passing from the monomeric unit 3 to its metallopolymeric counterpart 4.     

Syntheses and Structures of Octamethylmetallocenes of Osmium

The reaction of sodium hexachloroosmate(IV) hydrate with five equivalents of tetramethylcyclopentadiene (C₅Me₄H₂) in refluxing ethanol yielded the novel coordination compound bis(tetramethylcyclopentadienyl)chloroosmocinium(IV) hexachloroosmate, [(η ⁵-C₅Me₄H)₂OsCl]₂[OsCl₆] (1). Compound 1 has been characterized by NMR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The cationic complex of 1 [(η ⁵-C₅Me₄H)₂OsCl]⁺, adopts a bent geometry with a ring centroid-osmium-ring centroid angle of 146.2° and an eclipsed conformation of its two tetramethylcyclopentadienyl rings. The addition of zinc powder to sodium hexachloroosmate(IV) hydrate and five equivalents of tetramethylcyclopentadiene in refluxing ethanol produced the known compound, bis(tetramethylcyclopentadienyl)osmium, (η ⁵-C₅Me₄H)₂Os (2). The crystal structure of 2 has been determined and it reveals an eclipsed arrangement of the tetramethylcyclopentadienyl rings in the solid state. The average Os–C_ring bond length in octamethylosmocene 2 (2.187 Å) is in accordance with corresponding bond lengths in osmocene, (η ⁵-C₅H₅)₂Os (2.19 Å) and decamethylosmocene, (η ⁵-C₅Me₅)₂Os (2.18 Å).     

Theoretical study of the reactive intermediate Si2Me4[(η5-C5H4) Fe(CO)2] 2 2−

In two previous papers (Kinget al., J. Organomet. Chem. 19, 327, 1969; Pannellet al., Organometallics 9, 859, 1990), the synthesis and X-ray structure of the two tetramethyl disilyl complexes [(η⁵-C₅H₅) Fe(CO)₂]₂Si₂Me₄ (I) and Si₂Me₄[(η⁵-C₅H₄) Fe(CO)₂CH₃]₂ (II) were reported. ComplexII is obtained fromI [2]. However, attempts to form other derivatives fromI have generally failed. In the chemical process to getII fromI, an intermediate complex, Si₂Me₄[(η⁵-C₅H₄) Fe(CO)₂] ₂ ^2? (III), is probably formed. This is similar to complexII without the two methyl groups bonded to the Fe atoms. Therefore, a theoretical study that may shed some light on the intermediate structure, stability, and reactivity is justified. We have developed theoretical studies consisting of extended Huckel electronic structure calculations on the simulated intermediate geometry. The results obtained from these calculations suggest that it might be stable enough to form during reactions of complexI. The more reactive sites, which suggest reaction alternatives, are pointed out.     

Preparation, Crystal Structures and Photoluminescence of Two New Zinc Complexes Based on 1H-Imidazo[4,5-f][1,10]-phenanthroline and Auxiliary Ligands

Two new coordination polymers [Zn(ip)(2,5-tda)(H₂O)₂] _n (1) and [Zn₂(ip)₂(5-npa)₂] _n (2) (2,5-tda = thiophene-2,5-dicarboxylic acid, ip = 1H-imidazo[4,5-f][1,10]-phenanthroline and 5-npa = 5-Nitroisophthalic acid) were synthesized and characterized by IR, elemental analysis, PXRD and X-ray diffraction. Single-crystal X-ray analyses revealed that 1 and 2 demonstrate a 1D chain structure. Complex 1 was bridged by 2,5-tda ligands in a μ₁ ? η¹:η⁰/μ₁ ? η¹:η⁰ coordination mode, and further extended into a 2D supramolecular structure by hydrogen bonding and π···π interactions. In 2, the 5-npa ligand acts as a bridging moeity, exhibiting μ₁ ? η¹:η¹/μ₁ ? η¹:η⁰ and μ₁ ? η¹:η⁰/μ₁ ? η¹:η⁰ coordination modes to link metal ions to form a 1D chain. The chains are further connected via hydrogen bonding interactions into a 2D supramolecular structure. The luminescent properties for 1 and 2 were investigated in the solid state at room temperature.     

A Strategy for Preparing Star Polymers Containing Metal–Metal Bonds Along the Polymeric Arms Using Click Chemistry

The [(η⁵-C₅H₄(CH₂)₃N₃)Mo(CO)₃]₂ dimer (3) was prepared and used to determine if the Huisgen cycloaddition reaction could be used to synthesize high molecular weight star polymers with metal–metal bonds in the arms. Several different click catalysts were examined. Cp*Ru(PPh₃)₂Cl (Cp* = η⁵-C₅(CH₃)₅) was previously shown to catalyze the formation of metal–metal bond-containing polymers using click chemistry; however, this catalyst underwent a Staudinger reaction with dimer 3 when a model coupling reaction was attempted with phenylacetylene. In order to avoid the Staudinger reaction, Cp*Ru(COD)Cl was used as the catalyst in the reaction of 3 with phenylacetylene, and coupling was observed after 14 h. Synthesis of a star polymer was attempted with 3 and 1,3,5-triethynylbenzene. Instead of coupling, Cp*Ru(COD)Cl reacted with the 1,3,5-triethynylbenzene. A third catalyst, Cu(IMes)Cl (IMes = 1,3-dimesityl-imidazol-2-ylidene) was used to couple 3 with 1,3,5-triethynylbenzene in 48 h. Both a high molecular weight polymer (M _n  = 77,000 g mol^?1) and a tripodal star core (M _n  = 1,800 g mol^?1) were successfully prepared with this catalyst.     

Uranyl Coordination Polymers Incorporating η5-Cyclopentadienyliron-Functionalized η6-Phthalate Metalloligands: Syntheses,Structures and Photophysical Properties

The reaction of two η⁵-cyclopentadienyliron(II)-functionalized terephthalate and phthalate metalloligands, namely [(η⁵-C₅H₅)Fe^II(η⁶-1,4-HO₂CC₆H₄CO₂H)][(η⁵-C₅H₅)Fe^II(η⁶-1,4-HO₂CC₆H₄CO₂)][PF₆] and [(η⁵-C₅H₅)Fe^II(η⁶-1,2-HO₂CC₆H₄CO₂H)][(η⁵-C₅H₅)Fe^II(η⁶-1,2-HO₂CC₆H₄CO₂)][PF₆]—hereafter [H₂ CpFeTP][HCpFeTP][PF₆] and [H₂ CpFeP][HCpFeP][PF₆], respectively—with [UO₂(NO₃)₂]·6H₂O under hydrothermal conditions yielded four new coordination polymers; (1) [(UO₂)F(HCpFeTP)(PO₄H₂)]·2H₂O, (2) [(UO₂)₂(CpFeTP)₄]·5H₂O, (3) [(UO₂)₂F₃(H₂O)(CpFeP)], and (4) [H₂ CpFeP][UO₂F₃]. The use of metalloligands has proven to be a viable route towards the incorporation of a secondary metal center into uranyl bearing materials. Depending upon the protonation state, the iron sandwich metalloligands may vary from zwitterionic neutral or monoanionic coordinating species as observed in compounds 1–3, or a positively charged species that hydrogen bonds with anionic [UO₂F₃]^? chains as observed in 4. Further, the hydrolysis of the charge balancing PF₆ ^? anion increases the diversity of UO₂ ²⁺ coordinating species by contributing both F^? and PO₄ ^3? anions (1, 3, 4). The luminescent properties of 1–4 were also studied and revealed the absence of uranyl emission, suggestive of a possible energy transfer from the uranyl cation to the iron(II) metal center.     

Supramolecular Chemistry of Organoplatinum(IV) Complexes Bearing Ligands with Remote Carboxylic Acid Substituents

The oxidative addition of compounds RBr to [PtMe₂(bpox)], 1, bpox = 2,5-bis(2-pyridyl)-1,3,4-oxadiazole gave the corresponding organoplatinum(IV) complexes [PtBrMe₂(R)(bpox)], 2, R = CH₂CO₂H; 3, R = CH₂-4-C₆H₄CO₂H; 4, R = CH₂-4-C₆H₄CH₂CO₂H, whereas the reaction with BrCH₂CH₂CO₂H gave only the platinum(II) complex [PtBrMe(bpox)], 5. The organoplatinum(IV) complexes with carboxylic acid substituents form unusual supramolecular structures in the solid state through hydrogen bonding interactions, some of which are supramolecular polymers.     

The effect of [(η-C3H5)(η-C5H5)Mo(CO)2] on drying of solvent-borne alkyd paints

Allyl molybdenum complex [(η³-C₃H₅)(η⁵-C₅H₅)Mo(CO)₂] (Mo-A) was examined as a new drier for solvent-borne alkyd binder. The drying activity of pure Mo-A and the of combinations of Mo-A with cobalt(II) 2-ethylhexanoate (Co-Nuodex) was examined using standard methods for measurements of the drying time and hardness development of the alkyd film. The detailed study of the drying process was studied by time-resolved infrared spectroscopy on ethyl linoleate as well as on thin coating of alkyd binder.     

A Bimetallic Chain Based on [Mo(CN)8]3− and Er3+ Ions as Building Blocks: Synthesis and Magnetic Properties

A novel bimetallic 4d-4f complex, [Er^III(DMF)₄(H₂O)₂][Mo^V(CN)₈]·i-C₃H₇OH·4H₂O (1) (DMF = N,N′-dimethylformamide), has been synthesized and structurally characterized. The crystalline analysis shows that the build up of 1D zigzag-like chains produces complex 1, which is the first structurally characterized example of 1D structure based on the [Mo(CN)₈]^3? and Er³⁺ ions as building blocks. Complex 1 crystallizes in monoclinic system of space group P2₁/n, with a = 12.031(6), b = 16.027(7), c = 20.263(9) Å, β = 105.711(6)º and Z = 4. Magnetic measurements confirm that 1 presents probably a ferromagnetic interaction between the Mo^V and Er^III ions.     

Hydrothermal Syntheses,Crystal Structure and Characterization of Two Alkaline Earth Metal Coordination Polymers with 1-(4-Iodophenyl)-5-methyl-1H-[1,2,3]-triazole-4-carboxylate Ligand

Two new alkaline earth metal coordination polymers [M(ipmtca)₂(H₂O)]_n with M = Ca (1), Sr (2) have been obtained by the reactions of Ca²⁺ (1) and Sr²⁺ (2) with 1-(4-iodophenyl)-5-methyl-1H-[1,2,3]-triazole-4-carboxylic acid, respectively under hydrothermal conditions. The ligands link the metals to a 1D chain via carboxyl groups with μ ₃-(η ²:η ⁰) and μ ₃-(η ¹:η ²) coordination modes. The complexes are assembled into a 3D structure by the 1D chains via hydrogen bonding interactions. The structures have been established by single-crystal X-ray diffraction, and characterized by FT-IR, thermogravimetric analysis (TGA), solid UV–Vis spectroscopy, and solid-state fluorescent spectroscopy. TGA analysis confirmed the thermal stability of the complexes.     

Synthesis, Crystal Structures and Properties of Two Metal–Organic Frameworks Constructed from Pyridine Dicarboxylate and Flexible Bis(imidazole) Ligand

Two novel interesting metal–organic frameworks, [Zn(PDA)(bbi)] _n (1) and [Cd₂(PDA)₂(bbi)₂(H₂O)₂·10H₂O] _n (2) [H₂PDA = pyridine-2,6-dicarboxylic acid, bbi = 1,1′-(1,4-butanediyl)bis(imidazole)] have been isolated under hydrothermal conditions and structurally characterized. X-ray single crystal structure analysis reveals that complex 1 crystallize in monoclinic P2₁/c space group, while complex 2 crystallize in triclinic P-1 space group. The PDA^2? anions act in two different coordination modes: terminal chelating for 1 and chelating and bis-monoatomic bridging for 2. Polymeric chains of 1 and 2 are composed of Zn(II) and Cd(II) ions bridged by bbi ligands. The fluorescent properties of 1 and 2 were also investigated.     

Syntheses, Structures and Properties of Two 2D Transition Metal Coordination Polymers Based on Oxalate and Two Types of N-donor Auxiliary Ligands

Two new two-dimensional (2D) metal–organic coordination polymers [Co(ox)(bbbm)]·H₂O (1) and [Cu(ox)(bppdca)]·2H₂O (2) (H₂ox = oxalic acid, bbbm = 1,1-(1,4-butanediyl)bis-1H-benzimidazole and bppdca = N,N′-bis(pyridin-3-yl)-2,6-pyridinedicarboxamide) were synthesized under hydrothermal conditions and structurally characterized. Both 1 and 2 exhibit a 2D four-connected network formed by the Co^II/Cu^II ions as four-connected nodes; and, the ox anions and bbbm/bppdca ligands as linkers with a (4⁴.6²) topology as determined by single crystal X-ray diffraction. In addition, the thermal stability, electrochemical and luminescent properties for 1 and 2 were investigated.     

Crystal Structures and Luminescent Properties of Two Lanthanide(III) Complexes Featuring Double-Stranded Helical Chains of Based on 2-Sulfoterephthalate

Hydrothermal reaction of Eu³⁺ and Dy³⁺ salts with monosodium 2-sulfoterephthalate (NaH₂stp) gives two 2D lanthanide coordination polymers, [Ln(stp)(H₂O)₂] _n (Ln = Eu (1) and Dy (2)). Single-crystal X-ray diffraction of the complexes reveal that both 1 and 2 crystallize in the triclinic crystal system of Pī space group. For 1, each Eu³⁺ ion lies in a 9-coordinated slightly distorted tri-capped triangle pyramidal configuration. The stp ligands adopt a μ ₄-type link to the metal ions to form a 2D layer-like structure, of which there exist the left- and right-handed double-stranded helical chains. For 2, each Dy³⁺ ion is in a 8-coordinated distorted bi-capped triangle pyramidal geometry. The double-stranded helical chains in 2 differ from those in 1. The thermal stabilities of the two compounds are studied by TGA. The solid state photoluminescence of 1 and 2 are reported. The fluorescent decay curves of the ligand and compounds indicate that 1 has the lifetime of 286.7 μs, τ ₁ = 0.51 ns and τ ₂ = 3.07 ns for the ligand, and for 2, τ ₁ = 0.53 ns and τ ₂ = 2.71 ns.     

Ancillary Ligand-Mediated Syntheses,Structures and Fluorescence of Three Zn/Cd(II) Coordination Polymers Based on Nitrobenzene Dicarboxylate

The Zn/Cd(II)-nbdc carboxylate motifs mediated by various dipyridyl-typed ligands afforded three new coordination compounds, namely, [Zn(nbdc)(bpa)_0.5(H₂O)]·H₂O (1), [Zn₂(nbdc)₂(bpp)₂]·H₂O (2), and [Cd(nbdc)(bpe)_0.5(H₂O)₂] (3) (H₂nbdc = 4-nitrobenzene-1,2-dicarboxylic acid, bpa = 1,2-bi(4-pyridyl)ethane, bpe = 1,2-di(4-pyridyl)ethylene, and bpp = 1,3-bis(4-pyridyl)propane), which were synthesized by hydrothermal reaction and characterized by elemental analysis, IR, thermal analysis (TGA), and fluorescent analysis. The single-crystal X-ray diffractions reveal that three complexes display a diverse range of connectivity topology from 1D to 3D, which is dependent on the type of dipyridyl-typed ligands and metal centers. Complex 1 is the 1D chain featuring Zn-carboxylate binuclears extended further by bpa coligands. Complex 2 is the 2D thick-layer containing double-stranded chains cross-linked further by bpp coligands. Complex 3 is the 3D framework with (6³)(6⁵.8) ins topology featuring Cd-carboxylate chiral layers pillared by bpe coligands. The thermal stabilities and fluorescence properties for complexes 1–3 are investigated.     

Syntheses,Crystal Structures and Physical Properties of Four Zinc/Cadmium Coordination Polymers Based on 4-Nitrophthalic Acid and N-donor Auxiliary Ligands

Four new d¹⁰ metal coordination polymers, [Zn(4-NPA)(2,2-bipy)] _n (1), [Zn(4-NPA)(1,3-bimb)·H₂O] _n (2), [Cd(4-NPA)(2,2-bipy)] _n (3) and [Cd(4-NPA)(1,3-bimb)·H₂O] _n (4) (4-NPAH₂ = 4-nitrophthalic acid, 2,2-bipy = 2,2-bipyridine, 1,3-bimb = 1,3-bis(imidazol-1-ylmethyl)-benzene), have been hydrothermally synthesized and characterized by elemental analyses, IR spectra, and X-ray single crystal diffractions. Compounds 1?3 possess different one-dimensional (1D) chain structures. Compound 4 shows a two-dimensional (2D) layered structure. Moreover, the luminescent and thermal stabilities properties of compounds 1–4 were investigated in the solid state.     

Two New Luminescent Cadmium Thiolato-carboxylates with 2,2′-Bipyridine

Two new cadmium thiolato-carboxylate complexes, [Cd₂(mba)₂(2,2′-bpy)₂] (1), [Cd₂(dtba)₂(2,2′-bpy)₄]·4H₂O (2) (H₂mba = 2-mercaptobenzoic acid, H₂dtba = 2,2′-dithiodibenzoic acid, 2,2′-bpy = 2,2′-bipyridine) were obtained by reacting Cd(II) salts and the ligands of H₂mba and 2,2′-bpy, and were characterized by the single-crystal X-ray diffraction, IR, 2D-COS IR, solid UV, TG and XRD. In complex 2, the H₂dtba ligand came from the in situ S–S function reaction of H₂mba under the hydrothermal conditions. Complexes 1 and 2 are both 1D chains, but the difference lies in the linkage of the ligands. The 3D super-molecular frameworks of 1 and 2 are produced by π–π stacking interaction between the 2,2′-bpy ligands and the hydrogen bonds of O–H…O with ths-type and dia-type topology, respectively. The fluorescent emissions are observed in 1 and 2 with λ _em = 533 nm and λ _em = 436 nm, due to the ligand-to-metal charge transfer (LMCT) and π* → π transitions, respectively.     

A New Cd(II) Coordination Polymer with a Rare tfz-d Topology Constructed by Asymmetrically Tricarboxylate and Imidazole-Containing Ligand: Synthesis,Crystal structure and Luminescent Property

A new coordination polymer [Cd(Hbtc)(bib)_0.5] _n (1) (H₃btc = biphenyl-3,4′,5-tricarboxylate and bib = 1,4-bis(imidazol-1-yl)benzene) has been obtained under hydrothermal conditions. The structure of complex 1 has been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectrum. The complex 1 shows a (3,8)-connected twofold interpenetrated three-dimensional (3D) tfz-d topology with the point symbol (4³)₂ (4⁶·6¹⁸·8⁴). The photoluminescence behavior of complex 1 was also discussed in paper.     

Zirconocene silanolate complexes and their heterogeneous siliceous analogues as catalysts for phenylsilane dehydropolymerization

The efficient catalytic dehydropolymerization of phenylsilane by homogeneous zirconocene bissilanolates ([{(c-C₅H₉)₇Si₈O₁₂O}₂Zr(η⁵-C₅H₅)₂] (1a); [{(c-C₅H₉)₇Si₈O₁₂O}₂Zr(η⁵-C₅H₄Bu)₂] (1b) [{(c-C₅H₉)₇Si₇O₉(OSiMe₃)O₂}Zr(η⁵-C₅H₅)₂] (4); [{(Me₃CO)₃SiO}₂Zr(η⁵-C₅H₅)₂] (5)) and chlorosilanolates ([{(c-C₅H₉)₇Si₈O₁₂O}ZrCl(η⁵-C₅H₄Bu)₂] (2); ([{(c-C₅H₉)₇Si₇O₉O₃}Zr₂Cl(η⁵-C₅H₅)₄] (3a); [{(c-C₅H₉)₇Si₇O₉O₃}Zr₂Cl(η⁵-C₅H₄Bu)₄] (3b)) has been demonstrated. The presence of at least one silanol ligand in the zirconocene moiety was found essential for high catalytic performance. Solid state structure of complex 1a was determined by single crystal X-ray diffraction analysis. A series of nine zirconocene-siliceous catalysts were prepared by grafting of zirconocene moiety onto silica using three general methods: (a) reaction of [(η⁵-C₅H₅)₂ZrCl₂] with silica in the presence of NEt₃; (b) reaction of [(η⁵-C₅H₅)₂ZrMe₂] with silica; (c) reaction of solely [(η⁵-C₅H₅)₂ZrCl₂] with silica. Supported catalysts were characterized by ICP-MS, FT-IR, TGA and selected examples by XPS analysis. Those catalysts prepared by method (a) and (b) were found efficient in the phenylsilane polymerization although a higher Zr/monomer ratio had to be used in comparison with homogeneous analogues. The low concentration of residual silanol groups in supported catalysts was found essential for their high catalytic performance. Advantageous reusability of supported catalysts was demonstrated using SiO₂₍₅₀₀₎/Cp₂ZrCl₂/NEt₃(5.8). The catalytic performance was retained in three consecutive cycles producing polymers with almost identical properties.     

The First Two Examples of (R)-2-Chloromandelato Coordination Polymers: Synthesis,Structure, Magnetic and Ferroelectric Properties

Both (R)-2-Chloromandelato coordination polymers, [Cu(Clma)₂] _n 1 and [Mn(H₂O)(Clma)₂] _n 2, crystallizing in the polar chiral monoclinic space group P2₁ represent the first two examples of metal complexes with (R)-2-Chloromandelic acid (HClma) ligand. Through the (R)-2-Chloromandelate Clma^? ions, the penta- and hexa-coordinated metal atoms in 1 and 2 are linked into chains, _∞ ¹ {[Cu(Clma)](Clma)_2/2} _n and _∞ ¹ {[Mn(H₂O)(Clma)](Clma)_2/2} _n , respectively, and further assembled into 3D supramolecular architectures via hydrogen bonding and close packing interactions. They exhibit ferroelectricity (Pr = 0.03 and 0.01 μC cm^?2, Ec = 5.09 and 0.52 kV cm^?1, Ps = 0.10 and 0.17 μC cm^?2, respectively). The magnetic behaviors of 1 and 2 can be interpreted by means of a 1D chain model, where the magnetic exchanges are transmitted via carboxylate groups between metal atoms, and the best fit results in J = 2.97, ?0.15 cm^?1 for 1 and 2, suggesting ferromagnetic and antiferromagnetic interactions, respectively.