Stimuli‐Responsive Semi‐Fluorinated Polymer Brushes on Porous Silica Substrates

Summary: A diblock copolymer brush consisting of poly(methyl acrylate)‐block‐poly(pentafluoropropyl acrylate) (Si/SiO₂//PMA‐b‐PPFA) was synthesized on a porous silica substrate. The brush was exposed to selective solvents, as well as thermal treatments, to induce a surface rearrangement. The rearrangement resulted in the selective loss or creation of an ultrahydrophobic layer by location of the fluoropolymer segment. This work demonstrates that surface rearrangements observed on flat surfaces can be transferred to porous substrates.

Image of a water droplet in contact with an Si/SiO₂//PMA‐b‐PPFA ultrahydrophobic polymer brush, synthesized from a porous silica substrate.     

Polymerization of ethylene with self-immobilizing bis(phenoxyimine) catalytic systems

The kinetic features of polymerization of ethylene with five methylaluminoxane-activated selfim-mobilizing bis(phenoxyimine) complexes of titanium chloride, namely, bis{2-[(4-allyloxyphenylimino)methyl]-6-tert-butylphenoxy}TiCl₂, bis{2-[(4-allyloxyphenylimino)methyl]-4,6-di-tert-butylphenoxy}TiCl₂, bis{2-[(4-allyloxyphenylimino)methyl]-6-cumylphenoxy}TiCl₂, bis{2-[(4-allyloxyphenylimino)methyl]-4,6-dicumylphenoxy}TiCl₂, and bis{2-[(4-allyloxyphenylimino)methyl]-6-1-(4-tert-butylphenyl)ethylphenoxy}TiCl₂ have been studied. The activity of these complexes in the polymerization of ethylene in the temperature range 20–80°C and an ethylene pressure of 0.3 MPa has been investigated both in the homogeneous and polymer matrix-bound states. The self-immobilizing catalytic systems possess high activity (up to 40000 kg_PE/mol_cat MPa h) and give rise to ultrahigh-molecular-weight PE (M = (2–7) × 10⁶) with an improved morphology of polymer particles.     

Structure and reactivity of mono- and dinuclear diiminate zinc alkyl complexes

The synthesis, structure and reactivity of several diiminate ligands are presented. The syntheses of five representative β-diiminate (BDI) zinc alkyl complexes and one β-oxo-δ-diiminate (BODDI) zinc alkyl are described. BDI ligands with varying backbone and N-aryl substituents display different solid state structures. [(BDI)ZnR] are synthesized by the reaction of (BDI)H with ZnR₂ in quantitative yield. Previously reported (BDI-1)ZnEt is a three-coordinate monomer in the solid state whereas [(BDI-3)ZnEt]_∞ [(BDI-3)=2-((2,6-diisopropylphenyl)amido)-3-cyano-4-((2,6-diisopropylphenyl)imino-2-pentene] and [(BDI-4)ZnEt]_∞ [(BDI-4)=2-((2,6-diethylphenyl)amido)-3-cyano-4-((2,6-diethylphenyl)imino-2-pentene] form one dimensional coordination polymers. The bimetallic complex [(BODDI-1)(ZnEt)₂] [(BODDI-1)=2,6-bis((2,6-diisopropylphenyl)amido)-2,5-heptadien-4-one] is prepared through the reaction of (BODDI-1)H₂ with two equivalents ZnEt₂. Both [(BDI)ZnEt] and [(BODDI)ZnEt] complexes react with acetic acid to give the acetate complexes in moderate to high yields, offering a superior synthetic route to these complexes. [(BDI)ZnR] [BDI=(BDI-3) or 1,1,1-trifluoro-2-((2,6-diisopropylphenyl)amido)-4-((2,6-diethylphenyl)imino-2-pentene), (BDI-5)] complexes react with MeOH to produce [{(BDI)Zn(μ-OMe)}₂Zn(μ-OMe)₂] in moderate yields. The molecular structures of [(BDI-3)ZnEt], [(BDI-4)ZnEt], [(BODDI-1)(ZnEt)₂], [(BODDI-1)Zn₂(μ-OAc)₂], [{(BDI-3)Zn(μ-OMe)}₂Zn(μ-OMe)₂] and [{(BDI-5)Zn(μ-OMe)}₂Zn(μ-OMe)₂] have been determined by X-ray diffraction.     

Ring-Expanded N-Heterocyclic Copper(I) Boryl Complexes: The Structures of [(6-Dipp)CuBcat], [(6-Dipp)CuBneop], and [(6-Dipp)CuBhex]

σ-Bond metathesis reactions between [(6-Dipp)CuOtBu] (6-Dipp=:C({Dipp}NCH₂)₂CH₂, Dipp=2,6-iPr₂−C₆H₃) and three diboranes gave access to three new copper(I) boryl complexes [(6-Dipp)CuBcat], [(6-Dipp)CuBneop], and [(6-Dipp)CuBhex] (cat=1,2-O₂C₆H₄; neop=(OCH₂)₂C(CH₃)₂; hex=OC(CH₃)HCH₂C(CH₃)₂O). Whilst [(6-Dipp)CuBcat] and [(6-Dipp)CuBneop] formed rapidly in toluene, access to [(6-Dipp)CuBhex] required heating to 60 °C for days. The complexes were characterised by single-crystal X-ray crystallography which showed in all three cases that the systems were monomers and distorted-linear at the copper atom. The stability of [(6-Dipp)CuBneop] was found to be comparable to that of [(IPr*)Cu-Bneop] (IPr*=1,3-bis(2,6-(diphenylmethyl)-4-methylphenyl)imidazol-2-ylidene); it persisted in solution for days with no sign of decomposition. [(6-Dipp)CuBhex] is a rare crystallographically characterised example of a complex containing a boryl anion supported by the hexylene glycolato ligand.     

以1-苯基吡唑为主配体的红光Ir(III)配合物的合成及光电特性

合成了一种新型红色磷光配合物二(1-苯基咪唑) (1-苯基异喹啉)合铱((ppz)₂Ir(piq)), 通过核磁共振氢谱(¹H NMR)对其结构进行了表征, 通过紫外-可见(UV-Vis)吸收光谱、荧光光谱、低温磷光光谱、循环伏安法及含时密度泛函理论(TD-DFT)对其光物理性能及能级结构进行了研究. 制备了一系列基于(ppz)₂Ir(piq)的电致发光器件, 研究了(ppz)₂Ir(piq)的电致发光性质. 结果表明, (ppz)₂Ir(piq)的UV-Vis 吸收峰主要位于296、342、395 和460 nm, 固态粉末的室温磷光发射峰位于618 nm, 在2-甲基四氢呋喃(2-MeTHF)溶液中其低温磷光发射峰位于598 nm, 其三线态能级(E_T)为2.07 eV. (ppz)₂Ir(piq)的最高占据轨道(HOMO), 其主要定域于配体ppz 和金属Ir(III)上, 最低未占据轨道(LUMO)主要定域于配体piq 上. (ppz)₂Ir(piq)的HOMO和LUMO 能级分别为-5.92和-3.62 eV. 基于(ppz)₂Ir(piq)电致发光器件的优化掺杂浓度为8%-12% (w), 最大电致发光谱峰位于616 nm,最大电流效率约10 cd·A^-1, 最大功率效率为4.44 lm·W^-1, 色坐标保持在(0.65, 0.35)附近, 是一种潜在的饱和红光磷光材料.     

Single-Crystal to Single-Crystal Transformations: Stepwise CO2 Insertions into Bridging Hydrides of [(NHC)CuH]2 Complexes

Mechanistic studies of substrate insertion into dimeric [(NHC)CuH]₂ (NHC=N-heterocyclic carbene) complexes with two bridging hydrides have been shown to require dimer dissociation to generate transient, highly reactive (NHC)Cu−H monomers in solution. Using single-crystal to single-crystal (SC-SC) transformations, we discovered a new pathway of stepwise insertion of CO₂ into [(NHC)CuH]₂ without complete dissociation of the dimer. The first CO₂ insertion into dimeric [(IPr*OMe)CuH]₂ (IPr*OMe=N,N′-bis(2,6-bis(diphenylmethyl)-4-methoxy-phenyl)imidazole-2-ylidene) produced a dicopper formate hydride [(IPr*OMe)Cu]₂(μ-1,3-O₂CH)(μ-H). A second CO₂ insertion produced a dicopper bis(formate), [(IPr*OMe)Cu]₂(μ-1,3-O₂CH)(μ-1,1-O₂CH), containing two different bonding modes of the bridging formate. These dicopper formate complexes are inaccessible from solution reactions since the dicopper core cleanly ruptures to monomeric complexes when dissolved in a solvent.     

Heteroleptic rhodium complexes containing both the dipyrrin/cyclooctadiene ligands and application of [(η-C8H12)Rh(4-pyrdpm)] in the construction of homo-/hetero-bimetallic complexes

Heteroleptic rhodium(I) complexes with the general formulations [(η⁴-C₈H₁₂)Rh(L)] [η⁴-C₈H₁₂ = 1,5-cyclooctadiene; L = 5-(4-cyanophenyl)dipyrromethene, cydpm; 5-(4-nitrophenyl)dipyrromethene, ndpm; and 5-(4-benzyloxyphenyl)dipyrromethene, bdpm; 5-(4-pyridyl)dipyrromethene, 4-pyrdpm; 5-(3-pyridyl)dipyrromethene, 3-pyrdpm] have been synthesized. The complex [(η⁴-C₈H₁₂)Rh(4-pyrdpm)] have been used as a synthon in the construction of homo-bimetallic complex [(η⁴-C₈H₁₂)Rh(μ-4-pyrdpm)Rh(η⁵-C₅Me₅)Cl₂] and hetero-bimetallic complexes [(η⁴-C₈H₁₂)Rh(μ-4-pyrdpm)Ir(η⁵-C₅Me₅)Cl₂], [(η⁴-C₈H₁₂)Rh(μ-4-pyrdpm)Ru(η⁶-C₁₀H₁₄)Cl₂] and [(η⁴-C₈H₁₂)Rh(μ-4-pyrdpm)Ru(η⁶-C₆H₆)Cl₂]. Resulting complexes have been characterized by elemental analyses and spectral studies. Molecular structures of the representative mononuclear complexes [(η⁴-C₈H₁₂)Rh(ndpm)] and [(η⁴-C₈H₁₂)Rh(4-pyrdpm)] have been authenticated crystallographically.     

A stable binuclear complex containing PdHPd bonds

The preparations of the binuclear hydrido-bridged cations [(terdentate ligand)Pd(μ-H)Pd(terdentate ligand)]⁺ from [(terdentate ligand)Pd(acetone)]⁺ and NaO₂CH and [(terdentate ligand)Pd(μ-H)Pt(terdentate ligand)]⁺ from [(terdentate ligand)Pd(acetone)]⁺ and [(terdentate ligand)PtH] (terdentate ligand = 2,6-(Ph₂PCH₂)₂C₆H₃) are reported. The preparation of the cation [(terdentate ligand)Pt(μ-H)Pt(terdentate ligand)]⁺ is also reported.     

Poly(β-Amino acids). VI. Synthesis and conformational properties of poly[(r)-3-pyrrolidinecarboxylic acid]

Racemic and optically active 3-pyrrolidinecarboxylic acids (β-proline) were synthesized, and their polymers, poly[(RS)-β-proline] and poly[(R)-β-proline], were prepared by the polycondensation reaction of the p-nitrophenyl esters. Model compounds, N-cyclopentylcarboxylic acid pyrrolidide and N-cyclopentylcarbonyl-(R)-3-pyrrolidinecarboxylic acid pyrrolidide, were synthesized to elucidate the conformation of the polymer. The solution properties of poly[(R)-β-proline] and the model compounds were investigated by means of circular dichroism (CD) and NMR spectroscopy. The spectral patterns of the polymer and model compounds were similar in various solvents. Poly[(R)-β-proline] and poly[(RS)-β-proline] showed identical NMR spectra. These results suggest that poly[(R)-β-proline] may exist in a random conformation consisting of mixtures of cis and trans amide bonds. The conformational study of cyclopentanecarboxylic acid pyrrolidide by NMR spectroscopy with a shift reagent, Eu(fod)₃, in CDCl₃ implied that the plane containing the amide group bisects the cyclopentane ring. This suggests that each amide plane in the polymer in chloroform may also bisect the pyrrolidine ring.     

Fluorescence signaling of aromatic oxoanion inclusion within metal-ion activated molecular receptor complexes formed from 2-(9-anthracenylmethylamino)ethyl-appended cyclen

Our observations that 1-[2-[(9-anthracenylmethylamino)ethyl)-4,7,10-tris[(2S)-2-hydroxy-3-phenoxypropyl]-1,4,7,10-tetraazacyclododecane, L¹, complexes Cd(II) to form fluorescent [CdL¹]²⁺ which undergoes a fluorescence change when it acts as an aromatic anion receptor complex has caused us to explore further the potential development of an interesting sequestration/sensor system. Accordingly, three new, octadentate, fluorescent, macrocyclic ligands, 1-[2-[(9-anthracenylmethyl)((2S)-2-hydroxy-3-phenoxypropyl)amino]ethyl]-4,7,10-tris[(2S)-2-hydroxy-3-phenoxypropyl]-1,4,7,10-tetraazacyclododecane, (L²), 1-[2-[(9-anthracenyl-methyl)((2S)-2-hydroxy-3-(4??-methyl)phenoxypropyl)amino]ethyl]-4,7,10-tris[(2S)-2-hydroxy-3-(4??-methyl)phenoxypropyl]-1,4,7,10-tetraazacyclododecane, (L³), and 1-[2-[(9-anthracenylmethyl)((2S)-2-hydroxy-3-(4??-t-butyl)phenoxypropyl)amino]ethyl]-4,7,10-tris[(2S)-2-hydroxy-3-(4??-t-butyl)phenoxypropyl]-1,4,7,10-tetraazacyclododecane, (L⁴), have been prepared with a view to using their metal complexes to study aromatic anion sequestration. The eight-coordinate Cd(II) complexes of L² and L³, [CdL²](ClO₄)₂·5H₂O and [CdL³](ClO₄)₂·2H₂O·2Et₂O are both capable of acting as receptors for a range of aromatic oxoanions. This is demonstrated by perturbation of the anthracene derived fluorescence emission intensity as the guest aromatic oxoanion and the receptor complex combine. In 20% aqueous 1,4-dioxane the receptor complex/aromatic oxoanion association constants are in the range of 10^3.2 M^?1 (guest = p-hydroxybenzoate) to 10^7.3 M^?1 (guest = 3,4,5-trihydroxybenzoate).     

Arylgold(I) and aryl(triphenylphosphine)gold(I)compounds

Novel monomeric benzyl- and aryl-gold(I) triphenylphosphine complexes have been prepared. Pure, uncomplexed 2-[(dimethylamino)methyl]-phenylgold(I) has been isolated from the reaction of tetranuclear bis {2-[(dimethylamino)methyl]phenyl}goldlithium (R₄ Au₂ Li₂) with trimethyltin bromide.     

Exogenous bridging and nonbridging in Cu(II) complexes of Mannich base ligands: Synthesis and physical properties

Preparation of pentadentate ligands L¹, L², L³ and L⁴, where L¹ = 4-chloro-3-methyl-2[(prolin-1-yl)methyl]-6-[N-phenyl piperazin-1-yl)methyl]phenol, L² = 4-ethyl-2-[(prolin-1-yl)methyl]-6-[(N-phenyl piperazin-1-yl)methyl]phenol, L³ = 4-chloro-3-methyl-2-[(prolin-1-yl)methyl]-6-[N-methyl piperazin-1-yl]methyl phenol, L⁴ = 4-methoxy-2-[(prolin-1-yl)methyl]-6-[(N-phenyl piperazin-1-yl)methyl]phenol is described together with that of the corresponding Cu(II) complexes with various bridging motifs like OH, OAc and NO₂. The complexes are characterized by elemental analysis, electrochemical and electron paramagnetic spectral studies. Redox properties of the complexes in acetonitrile are highly quasireversible due to the chemical or/and stereochemical changes subsequent to electron transfer. The complexes show resolved copper hyperfine EPR at room temperature, indicating the presence of weak antiferromagnetic coupling between the copper atoms. Strengths of the antiferromagnetic interactions are in the order NO₂>OAc>OH.     

[(R)-2-Methyl-1,4,7-triazacyclononane] [1,1,1-tris(aminomethyl)ethane]-cobalt(III) and some Mono[(R)-2-methyl-1,4,7-triazacyclononane]-cobalt(III) Complexes

Summary [(R)-2-Methyl-1,4,7-triazacyclononane][1,1,1-tris(aminomethyl)ethane]cobalt(III) has been prepared and separated into two isomers which show weak Cotton effects in the¹A₁¹T₁ region (d-electron transition) compared with that of bis[(R)-2-methyl-1,4,7-triazacyclononane]cobalt(III). The effect is comparable to that of tetraammine[(R)-1,2-diamino propane]cobalt(III). The circular dichroism spectra of the mono complex change markedly upon addition of sodium sulphate. The chelate rings are more flexible in the mono than in the bis complex. Some other related mono[(R)-2-methyl 1,4,7-triazacyclononane]cobalt(III) and [(R)-2-methyl-1,4,7 triazacyclononane][1,1,1-tris(aminomethyl)ethaneI nickel (II) complexes have also been prepared and characterized.     

Chemistry of dihydrogen complexes containing only phosphorus co-ligands

A series of new dicationic dihydrogen complexes of ruthenium of the typecis-[(dppm)₂Ru(η₂-H₂)(L)][BF₄]₂ (dppm = Ph₂PCH₂PPh₂; L = phosphite) have been prepared by protonating the precursor hydride complexescis-[(dppm)₂Ru(H)(L)][BF₄] using HBF₄•Et₂O. The precursor hydride complexes have been obtained fromtrans-[(dppm)₂Ru(H)(L)][BF₄] (L = phosphite) via a rare acid-catalysed isomerization reaction in six coordinate species. Thetrans-[(dppm)₂Ru(H)(L)][BF₄] complexes (L = phosphine) upon protonation gave the isomerized derivatives, however, further addition of acid resulted in a five-coordinate species, [(dppm)₂RuCl]⁺ presumably via an intermediate phosphine dihydrogen complex. The electronic as well as the steric properties of the co-ligands seem to strongly influence the structure-reactivity behaviour of this series of complexes.     

Poly[(3-hydroxypropyl) oxirane] and poly[(4-hydroxybutyl)oxirane]: New hydrophilic polyether elastomers

Preparations of poly[(3-hydroxypropyl)oxirane] and poly[(4-hydroxybutyl)oxirane] are described. Three routes to poly[(3-hydroxypropyl)oxirane] are discussed, each of which involves the methanolysis of a polymeric ester. (3-Acetoxypropyl)oxirane, [3-(m-chlorobenzoyloxy)propyl]oxirane, and (3-chloropropyl)oxirane were polymerized using the AIEt₃/H₂O/AcAc initiator system. Poly[(3-acetoxypropyl)oxirane] and poly{[3-(m-chlorobenzoyloxy)propyl]oxirane} were converted directly to poly[(3-hydroxypropyl)oxirane] by methanolysis, the former under either acidic or basic conditions only. Poly[(3-chloropropyl)oxirane] was first converted to poly[(3-benzoyloxypropyl)oxirane] by treatment with tetrabutylammonium benzoate; subsequent basic methanolysis then afforded poly[(3-hydroxypropyl)oxirane]. Poly[(3-hydroxypropyl)oxirane] is a colorless elastomer which can be cast into tough, clear films from water or methanol. Poly[(4-hydroxybutyl)oxirane] was prepared from poly[(4-chlorobutyl)oxirane] by benzoyloxylation and subsequent methanolysis. Poly[(4-hydroxybutyl)oxirane] is insoluble in water, but is hydrophilic and can be cast into tough films from methanol or dimethylsulfoxide.     

Synthesis and molecular properties of new poly(naphthalene-1, 3, 4-oxadiazole)s

Poly[(1, 4-naphthalene)-2, 5-diyl-1, 3, 4-oxadiazole] and poly[(2, 6-naphthalene)-2, 5-diyl-1, 3, 4-oxadiazole] have been synthesized and investigated in conc. H₂SO₄, by the flow birefringence method, in comparison with poly[(1, 4-phenylene)-2, 5-diyl-1, 3, 4-oxadiazole]. Changes in conformation parameters and optical anisotropy of a chain unit induced by incorporation of the naphthalene groups into the macromolecule backbone have been evaluated.     

Ab Initio Calculations of Hydroxoplatinum Compounds: II. Binuclear Platinum(IV) Superoxo Complexes

The structural and spectral data have been obtained by ab initio methods for the [(OH)₄Pt(μ-O₂)(μ- OH)Pt(OH)₄]^2?, [(OH)₄Pt(μ-O₂)(μ-OH)Pt(OH)₄(OH)]^3?, [(OH)₅Pt(μ-O₂)Pt(OH)₅]^3?, and [(H₂O)(OH)₄Pt(μ- O₂)Pt(OH)₄(H₂O)]- clusters, corresponding to binuclear platinum(IV) superoxo complexes with one and two bridges. The data obtained are in good agreement with experimental data and make it possible to judge the structure of available complexes.     

螺桨烷型分子BX[(CH_2)_n]_3和BX(CH_2)[CH(CH_2)_nCH](X=N,P)的结构和性质

采用密度泛函理论(DFT)研究了螺桨烷型分子BX[(CH2)n]3和BX(CH2)[CH(CH2)n CH](X=N,P;n=1-6)的结构、稳定性、化学键和电子光谱性质.计算结果表明这些分子都是稳定的.BX[(CH2)n]3(X=N,P;n=1-6)的最高占据分子轨道(HOMO)和最低空分子轨道(LUMO)之间的能隙均大于5.20 eV,其中BN[CH2]3和BP[CH2]3的能隙超过7.0 eV,与C5H6的能隙(7.27 eV)很接近,BX(CH2)[CH(CH2)n CH](X=N,P;n=1-6)的能隙在6.80 eV左右.所研究分子能量的二阶差分表明BN[(CH2)3]3、BP[(CH2)4]3及BX(CH2)[CH(CH2)2CH](X=N,P)是最稳定的.BX[(CH2)n]3的Wiberg键级表明除了BN[(CH2)n]3(n=2和6)中不存在B―N键,其它化合物中B和N均形成了化学键,BP[(CH2)n]3中除了BP[(CH2)2]3不存在B―P键,其它的均存在.电子密度的拓扑分析表明N―B键属于离子键,而P―B键具有共价键特征.BX[(CH2)n]3(X=N,P)的第一垂直激发能分别在191.1-284.8 nm和191.8-270.1 nm之间,BX(CH2)[CH(CH2)n CH](X=N,P)的第一垂直激发能分别在190.5-199.7 nm和209.0-221.3 nm之间.     

Anomalous behaviour of an allyl alcohol in reaction with iron pentacarbonyl

[(6,7,8,9-η)-Bicyclo[3.2.2]nona-2,6,8-trien-4-ol]tricabonyliron (6) rearranges in the presence of Fe(CO)₅ to [(2,3,6,7-η)-bicyclo[3.2.2]nona-2,6,8-trien-4-one] tricarbonyliron (7); rather than [(6,7,8,9-η)-bicyclo-[3.2.2]nona-6,8-dien-2-one] tricarbonyliron (9), the product expected on the basis of known organoiron chemistry and previously proposed mechanisms. The starting material 6 is stable in the absence of Fe(CO)₅, which leads to the conclusion that some iron-containing species derived from fe(CO)₅ is responsible for bringing about rearrangement. Since the usual mechanism for iron carbonyl-induced rearrangement in olefins cannot be operating here, a mechanism involving an ion pair with [HFe(CO)₄]^- is suggested.     

The reactions between tetrachloroplatinate(II) anion and bidentate sulphur-nitrogen chelating agents: A direct route for the synthesis of the neutral dichloro species

A direct route for the synthesis of the neutral dichloro complexes [Pt(NS)Cl₂], (NS = 2-[(ethylthio)methyl]pyridine and 2-[(phenylthio)methyl]pyridine) in dimethylformamide, which avoids the formation of bis-chelate cations, is reported.