Syntheses,characterizations and properties of boronoalkylalkoxycalix[4]arenes

Some new calixarenes bearing boronic acid moieties, boronoalkylalkoxycalix[4]arenes, were synthesized by allylation, Claisen's rearrangement, alkylation, hydroboration and hydrolysis from 25,26,27,28-tetrahydroxycalix[4]arene and their structures were identified by elemental analysis, IR, ¹H NMR, ¹³C NMR, ¹¹B NMR, MS and UV spectra. The UV data showed that tetraalkoxycalix[4]arene tetraalkyltriboronic acid could coordinate significantly with carbohydrates.     

Syntheses, characterization and ethylene polymerization of half-sandwich group IV metal complexes with tridentate [O,N,S] ligands

A series of half-sandwich group IV metal complexes with tridentate monoanionic phenoxy-imine arylsulfide [O NS] ligand [2-Bu t 4-Me-6-((2-(SC 6 H 5)C 6 H 4 N = CHC 6 H 2 O)](La) and dianionic phenoxy-amine arylsulfide [O N S] ligand [2-Bu t 4-Me-6-((2-(SC 6 H 5)C 6 H 4 N-CH 2 C 6 H 2 O)] 2(Lb) have been synthesized and characterized.Lb was obtained easily in high yield by reduction of ligand La with excess LiAlH 4 in cool diethyl ether.Half-sandwich Group IV metal complexes CpTi[O NS]Cl 2(1a),CpZr[O NS]Cl 2(1b),CpTi[O N S]Cl(2a),CpZr[O N S]Cl(2b) and Cp * Zr[O N S]Cl(2c) were synthesized by the reactions of La and Lb with CpTiCl 3,CpZrCl 3 and Cp * ZrCl 3,and characterized by IR,1 H-NMR,13 C-NMR and elemental analysis.In addition,an X-ray structure analysis was performed on ligand Lb.The title Group IV half-sandwich bearing tridentate [O,N,S] ligands show good catalytic activities for ethylene polymerization in the presence of methylaluminoxane(MAO) as co-catalyst up to 1.58 × 10 7 g-PE.mol-Zr 1.h 1.The good catalytic activities can be maintained even at high temperatures such as 100 ℃ exhibiting the excellent thermal stability for these half-sandwich metal pre-catalysts.     

[Mo12S12O12(OH)12(H2O)6]: A Cyclic Molecular Cluster Based on the [Mo2S2O2]2+ Building Block

The pH-dependent self-condensation of the [Mo ₂ S ₂ O ₂ ] ²⁺ complex fragment gives the wheellike Mo₁₂ cluster depicted on the right (ball-and-stick model; large balls: S, medium balls: O, small balls: Mo). Applying this synthetic strategy to other starting materials could provide access to other polyoxothiometalates with well-defined cavities.     

Syntheses, reactions, and ethylene polymerization of titanium complexes with [N,N,S] ligands

Tridentate dianionic arylsulfide free ligands [ArNHCH(2)C(6)H(4)NHC(6)H(4)-2-SPh] (Ar = Ph (3a); Ar = 2,4,6-trimethylphenyl (3b); Ar = 2,6-diisopropylphenyl (3c)) have been prepared by reduction of the corresponding imine compounds [ArN[double bond, length as m-dash]CHC(6)H(4)NHC(6)H(4)-2-SPh] (Ar = Ph (2a); Ar = 2,4,6-trimethylphenyl (2b); Ar = 2,6-diisopropylphenyl (2c)) with LiAlH(4) in high yields. Reactions of TiCl(4) with the tridentate dianionic arylsulfide free ligands (3a-3c) afford five-coordinate and four-coordinate titanium complexes [κS, κ(2)N-(ArNHCH(2)C(6)H(4)NHC(6)H(4)-2-SPh)TiCl(2)] (Ar = Ph (4a); Ar = 2,4,6-trimethylphenyl (4b)] and [κ(2)N-(ArNHCH(2)C(6)H(4)NHC(6)H(4)-2-SPh)TiCl(2)] (Ar = 2,6-diisopropylphenyl (4c)], respectively. The molecular structures of compounds 2b, 2c, 3b and 3c·HCl have been characterized by single crystal X-ray diffraction analyses. Complexes 2a-4c are characterized by IR,(1)H-NMR spectra, and elemental analysis. EXAFS spectroscopy performed on complexes 4b and 4c reveals the expected different coordination geometry due to steric hindrance effect. When activated by excess methylaluminoxane (MAO), 4a-4c can be used as catalysts for ethylene polymerization and exhibit moderate to good activities.     

Photophysical and novel charge-transfer properties of adducts between [RuII(bpy)3]2+ and [S2Mo18O62]4-

The photophysical properties of acetonitrile solutions of [Ru(bpy)(3)](2+) and [S(2)Mo(18)O(62)](4-) are described. We discuss evidence for ion cluster formation in solution and the observation that despite the strong donor ability of the excited state of [Ru(bpy)(3)](2+) and its inherent photolability, adducts with [S(2)Mo(18)O(62)](4-) were photostable. Photophysical studies suggest that the quenching of the [Ru(bpy)(3)](2+) excited state by [S(2)Mo(18)O(62)](4-) occurs via a static mechanism and that binding is largely electrostatic in nature. Evidence is provided from difference spectroscopy and luminescence excitation spectroscopy for good electronic communication between [Ru(bpy)(3)](2+) and [S(2)Mo(18)O(62)](4-) with the presence of a novel, luminescent, inter-ion charge-transfer transition. The identity of the transition is confirmed by resonance Raman spectroscopy.     

1,1'-Di(heteroatom)-functionalised ferrocenes as [N,N], [O,O] and [S,S] chelate ligands in transition metal chemistry

Dppf is one of the most useful and popular ligands in coordination chemistry. Its overwhelming success has overshadowed and arguably even delayed the development and use of closely related ferrocene-based ligands with two ligating N, O or S atoms. Recently, however, dynamic progress concerning such homo-donor ligands can be noted. This tutorial review describes the main results obtained over the past decade in order to introduce the reader to an exciting field which currently shows particularly rapid development. The material is organised in sections according to ligand type, followed by a section which summarises the applications reported so far.     

Nickel complexes of bidentate [S2] and [SN] borato ligands

Nickel(II) complexes of the monoanionic borato ligands [Ph2B(CH2SCH3)2] (abbreviated Ph2Bt), [Ph2B(CH2S(t)Bu)2] (Ph2Bt(tBu)), [Ph2B(1-pyrazolyl)(CH2SCH3)], and [Ph2B(1-pyrazolyl)(CH2S(t)Bu)] have been prepared and characterized. While [Ph2Bt] formed the square planar homoleptic complex, [Ph2Bt]2Ni, the larger [S2] ligand with tert-butyl substituents, [Ph2BttBu], yielded an unexpected organometallic derivative, [Ph2Bt(tBu)]Ni(eta2-CH2SBut), resulting from B-C bond rupture. The analogous thiametallacycle derived from the [S3] ligand, [PhB(CH2S(t)Bu)3] (PhTt(tBu)), has been structurally authenticated (Schebler, P. J.; Mandimutsira, B. S.; Riordan, C. G.; Liable-Sands, L.; Incarvito, C. D.; Rheingold, A. L. J. Am. Chem. Soc. 2001, 123, 331). The [SN] borato ligands formed exclusively the cis stereoisomers upon reaction with Ni(II) sources, [Ph2B(1-pyrazolyl)(CH2SR)]2Ni. Analysis of the Ni(II/I) reduction potentials by cyclic voltammetry revealed a approximately 600 mV anodic shift upon replacement of two thioether donors ([Ph2Bt]2Ni) with two pyrazolyl donors ([Ph2B(1-pyrazolyl)(CH2SCH3)]2Ni) consistent with the all thioether environment stabilizing the lower oxidation state of nickel.     

Syntheses, structures, and anion-binding properties of two novel calix[2]benzo[4]pyrroles

Calix[2]benzo[4]pyrrole m-6 and p-6, each containing two dipyrromethane moieties and two m-phenylene or p-phenylene units, respectively, were readily synthesised from pyrrole, 1,3- and 1,4-bis(1,1'-dimethylhydroxymethyl)benzene, (m-4 and p-4, respectively) and acetone. Macrocycles m-6 and p-6 were tested as receptors for a selection of anions, such as acetate, dihydrogenphosphate and fluoride. The X-ray structures of m-6 and p-6 and those of the complexes m-6F(-), m-6Cl(-) and m-6CH(3)COO(-) (with an nBu(4)N(+) counterion) were also determined.     

杯[6]芳烃聚合物的合成与吸附性能

合成了一系列新型含酰氨基和酯基的杯[6]芳烃聚合物，并研究了它们对阳离子的吸附性能。发现与杯[4]聚合物相比，它们对体积较大的阳离子有较好的吸附作用，其中聚合物2c还对Ag^ 表现出较好的选择性吸附能力。     

Syntheses and structural characterizations of Fe4S4 cubane-like cluster compounds containing cycloalkylthiolate ligands

In a reaction system consisting of FeCl₂, tetrathiometallate and cycloalkylthiolate, two Fe₄S₄ cubanelike cluster compounds were obtained with the following crystallographic data: (PhCH₂NMe₃)₂ [ Fe₄S₄ (SC₅H₉)₄] (I), monoclinic space groupP2₁/c,a = 1.632 7(4),b=1.122 9(3),c = 2. 802 5(10) nm, β= 94.63(2)°, Z=4, andR= 0.074; (Et₄N)₂[F₄S4(SC₆H_lI)₄] (II), tetragod space group ,a = l.167 05(9),b = 1.167 06(2),c = 2.063 26(5) nm,Z = 2, D_obs = 1. 28 g/cm³, andR = 0. 078. The participation of cycloalkylthiolate ligand does not obviously arouse the change of the Fe₄S₄ core structure. Meanwhile, the influence of the cation on the structural symmetry of the Fe₄S₄ cluster dianion is also discussed. Project supported by the National Natural Science Foundation of China and the Climbing Program Foundation of China.     

Synthesis and optoelectronic properties of transition metal complexes incorporating dithieno[3,2-b:2',3'-d]phosphole ligands

A series of dithieno[3,2-b:2',3'-d]phosphole-based transition metal complexes, including Au, Fe, Pt, Rh and W as central metals have been synthesised and characterised. Structural investigations by X-ray single crystal crystallography supported the high degree of pi-conjugation in the dithienophosphole ligands. This essential requirement for potential applications in molecular electronics and optoelectronics provides small band gaps for the materials. Investigations toward the optoelectronic properties of the respective complexes by fluorescence spectroscopy indicated that systematic alterations of the electronic structure are connected to different variables such as transition metal employed, functionalisation of the dithienophosphole ligands as well as complex geometries. The investigated Pt-based complexes exhibit only poor photoluminescence whereas Rh-, W- and Fe-based species with silyl functionalised dithienophosphole ligands show appreciable photophysical properties. The Au complexes investigated exhibit strong photoluminescence properties with very intriguing features in terms of excitation and emission wavelengths, intensity as well as selectivity.     

On the studies of the vibrational spectra of cluster [Mo2O2S2(S2)2]2-

IR and Raman spectra of [Mo₂O₂S₂(S₂)₂]^2- were reported. The resonance Raman spectra and the depolarization ratios in CH₃CN solution were measured. By using the data of crystal structure, the simplified normal coordinate calculation of the stretching vibrations for anion [Mo₂O₂S₂(S₂)₂]^2- was performed. The results obtained are useful to assign the vibrational bands of some Mo-Fe-S clusters.     

Ethylene polymerization by the chromium catalysts based on bidentate [O,PO] or [S,P] ligands

Novel chromium catalysts based on bidentate phenoxy‐phosphinoyl (HO‐2R₁‐4R₂‐6(Ph₂P?O)C₆H₂: R₁ = R₂ = H, 3a ; R₁ = tBu, R₂ = H, 3b ; R₁ = R₂ = tBu, 3c ; R₁ = R₂ = cumyl, 3d ; R₁ = anthracenyl, R₂ = H, 3e ) and thiophenol‐phosphine (HS‐2R₁‐4R₂‐6(Ph₂P)C₆H₂: R₁ = R₂ = H, 4a ; R₁ = SiMe₃, R₂ = H, 4b ) were prepared and characterized. Treatment with modified methyaluminoxane, these catalysts displayed moderate to high‐catalytic activities for ethylene polymerization. The activities of them were higher than those of the corresponding catalysts based on bidentate phenoxy‐phosphine ligands. Both the coordinated donors and the ortho‐substituent of the ligands played an important role in improving catalytic activity. The effects of reaction parameters, such as cocatalyst and Al/Cr molar ratio as well as reaction temperature, on ethylene polymerization behaviors were investigated in detail for two favorable catalytic systems, 3b /CrCl₃(thf)₃ and 4b /CrCl₃(thf)₃. Catalyst 4b /CrCl₃(thf)₃ displayed higher catalytic activity and better temperature tolerance for ethylene polymerization than 3b /CrCl₃(thf)₃. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 311–319, 2010     

Solvothermal Synthesis, Crystal Structure, and Properties of the New Oxothiomolybdate Ni(dien)2[Mo2O2S6]

Summary.  The reaction of NiCl₂ · 6H₂O, Na₂MoO₄ ċ 2H₂O, and sulfur in a mixture of diethylenetriamine and 0.2 M ammonia solution (1:4) under solvothermal conditions leads to the formation of orange-red crystals of the oxothiomolybdate Ni(dien)₂[Mo₂O₂S₆] (dien = diethylenetriamine) in nearly 100% yield. The structure consists of [Ni(dien)₂]²⁺ cations and discrete dimeric [Mo₂O₂S₆]²⁻ anions. The compound crystallizes in the monoclinic space group P2₁/c (a = 8.726(2), b = 18.111(4), c = 14.419(3) ?, β = 101.686(3)°). Upon heating the compound decomposes in a single step starting at about 250°C. The final decomposition product was identified by X-ray powder diffractometry as MoS₂ and Ni₃S₂. Spectroscopic data as well as detailed synthetic procedures for Ni(dien)₂[Mo₂O₂S₆] are reported. Received November 6, 2000. Accepted November 17, 2000