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Preparation and storage of biorenewable, monomeric indenone, much less the polymerization to a well-defined, high-molecular-weight polymer, is challenging because of antiaromaticity-driven radical autopolymerization. Herein, we report the successful preparation and subsequent Lewis pair polymerization (LPP) of indenone without autopolymerization side reactions using Lewis pairs consisting of sterically encumbered Lewis acid (LA) catalysts, such as B(C6F5)3 and bis(2,6-tert-butyl-4-methylphenoxy)methylaluminum and Lewis base initiators such as silyl ketene acetal and N-heterocyclic olefin nucleophiles. Thus, for the first time, the LPP enabled the synthesis of polyindenone (Pin) with high number-average molecular weight (Mn = 1.72 × 105 g mol–1) and low dispersity (D = 1.13). Observed correlations between the steric bulk of the LA catalyst and diastereoselectivity (57–75%) created the opportunity to model and investigate the relationships between β-substituted monomer motifs, catalyst steric accessibility...

Aims To characterize the mechanisms by which bacteria in the peanut rhizosphere promote plant growth and suppress Aspergillus niger, the fungus that causes collar rot of peanut. Methods and results 131 isolates cultured from the peanut rhizosphere were assayed for growth promotion in a seedling germination assay. The most effective isolate, RR18, was identified as Burkholderia sp. by 16S sequencing analysis. RR18 reduced collar rot disease incidence and increased the germination rate and biomass of peanut seeds, and had broad-spectrum antifungal activity. Quantitative analyses showed that RR18 induced long-lasting accumulation of jasmonic acid, salicylic acid, and phenols, and triggered the activity of six defense enzymes related to these changes. Comparative proteomic analysis of treated and untreated seedlings revealed a clear induction of four abundant proteins, including a member of the pre-chorismate pathway, a regulator of clathrin-coated vesicles, a transcription factor, and a hypothetical protein. Conclusion Burkholderia sp. RR18 promotes peanut growth and disease resistance, and stably induces two distinct defense pathways associated with systemic resistance. Significance and impact of the study This study demonstrates that a strain of the Burkholderia cepacia complex can elicit both salicylic and jasmonic-acid mediated defenses, in addition to having numerous other beneficial properties.

Current methods for hydrogenation of bio-derived itaconic acid (IA) lead to a mixture of isomeric lactone products. Transition-metal nanoparticles (TM-NPs), in situ-generated through thermolysis of TM(0) (Ru, Fe, W, Cr) carbonyls, in particular Ru-NPs, were found to catalyze regioselective hydrogenation of IA by syngas (2 H2 /CO) into γ-isovalerolactone (GiVL) in approximately 70 % isolated yield. Key sustainability features of this new route include: a one-pot direct transformation of bio-renewable IA into value-added GiVL selectively, use of inexpensive and renewable syngas in aqueous solution, and development of a supported recyclable NP catalyst system, Al2 O3 -Ru-NPs.

Cu2ZnSnS4 (CZTS) films of different Thiorea (SC (NH2)2) molarity were deposited by using simple chemical spray technique at substrate temperature 275°C. Analytical reagent Grade Copper chloride (CuCl2), Zinc chloride (ZnCl2), Tin chloride (SnCl4.5H2O) were used as Cu+ , Zn+ , and Sn+ ion sources respectively and thiourea (SC(NH2)2) (0.02, 0.04 0.06 0.08, and 0.1 M) was used as a Sion source. A set of five CZTS films was deposited using five different molarity of thiourea. The structure, Morphology, Elemental analysis and optical properties of these films were studied using X-ray diffratometer (XRD), Scanning Electron Microscopy (SEM) Energy Dispersive X-ray Analysis (EDX) and UV-Visible spectroscopy techniques respectively. The XRD spectra showed that all films are polycrystalline tetragonal structure with preferential orientation along (112) plane. The calculated crystallite size was increased with increase in thiourea concentration. Variations of optical band gap with thiourea molarity have been investigated using Tauc plots. SEM micrographs exhibits CZTS spherical granules regularly arranged with some void spaces. Purity of deposited films was investigated using EDX analysis. All the CZTS films exhibits higher absorption coefficient (𝛼 > 104) cm-1 and band gap in the reported range (1.2-1.53 eV) can be used as an absorber layer in solar cells.

Group transfer polymerization (GTP) is an important ambient-temperature living polymerization method using silyl ketene acetal (SKA) or related initiators. Although several different GTP systems have been developed for polymerizing acrylic monomers, they all require the use of a catalyst to activate the SKA initiator, commonly believed to be ineffective on its own. Now, this work shows that, in fact, the neutral SKA alone mediates either controlled or extremely rapid polymerization of acrylic monomers such as methyl methacrylate (MMA) in polar donor solvents such as DMF, depending on the nuclearity of the SKA and the chelating pendant group on Si. In the case of a mono-SKA such as Me2C═C(OMe)OSiMe3, the GTP of MMA in DMF is relatively slow (several hours to completion) but is controlled and remarkably efficient, producing PMMA with Mn values close to those predicted on the basis of the [M]/[I] ratio, low Đ values (≤1.2), and high initiation efficiencies (≥80%). In sharp contrast, the di-SKAs linked by an ...

Achieving complete chemoselectivity in the polymerization of multivinyl polar monomers is an important yet challenging task, currently achievable only by metal- or metalloid-mediated polymerization processes but in a noncatalytic fashion. Now this work shows that organic N-heterocyclic carbene (NHC) catalysts effect rapid, chemoselective, and catalytic polymerization of multivinyl-functionalized γ-butyrolactones, particularly γ-vinyl-α-methylene-γ-butyrolactone (VMBL). Thus, the NHC-catalyzed polymerization of VMBL not only is quantitatively chemoselective, proceeding exclusively via polyaddition across the conjugated α-methylene double bond while leaving the γ-vinyl double bond intact, but also requires only an exceptionally low catalyst loading of 50 ppm, thus, exhibiting a remarkably high catalyst turnover frequency of 80000 h–1 and producing on average 33.6 polymer chains of Mn = 73.8 kg/mol per NHC molecule. The resulting PVMBL can be either thermally cured into cross-linked materials or postfunction...

Nanoparticles (NPs) derived from earth-abundant metal(0) carbonyls catalyze conversion of bio-derived levulinic acid into γ-valerolactone in up to 93% isolated yield. This sustainable and green route uses non-precious metal catalysts and can be performed in aqueous or ethanol solution without using hydrogen gas as the hydrogen source. Generation of metal NPs using microwave irradiation greatly enhances the rate of the conversion, enables the use of ethanol as both solvent and hydrogen source without forming the undesired ethyl levulinate, and affords recyclable polymer-stabilized NPs.

Multivinyl-functionalized γ-butyrolactones, γ-vinyl-γ-methyl-α-methylene-γ-butyrolactone ( γ VMMBL) and γ-allyl-γ-methyl-α-methylene-γ-butyrolactone ( γ AMMBL), have been synthesized from biorenewable ethyl levulinate and effectively polymerized by Lewis pairs consisting of an organic N -heterocyclic carbene Lewis base and a strong organo-Lewis acid E(C 6 F 5 ) 3 (E = Al, B). This Lewis pair polymerization is quantitatively chemoselective, proceeds exclusively via polyaddition across the conjugated α-methylene double bond without participation of the γ-vinyl or γ-allyl double bond, and produces high-molecular-weight functionalized polymers with unimodal molecular-weight distributions. The Al-based Lewis pair produces a polymer with approximately 5.5 times higher molecular weight than that produced by the B-based Lewis pair. The resulting vinyl-functionalized polymers are soluble in common organic solvents and stable at room temperature, and can be thermally cured into crosslinked materials. This article is part of the themed issue ‘Frustrated Lewis pair chemistry’.

Group 4 tetrabenzyl compounds MBn4 (M = Zr, Ti), upon protonolysis with an equimolar amount of the tetradentate amine-tris(phenol) ligand N[(2,4-tBu2C6H2(CH2)OH]3 in toluene from −30 to 25 °C, unexpectedly lead to amine-bis(phenoxy) dibenzyl complexes, BnCH2N[(2,4-tBu2C6H2(CH2)O]2MBn2 (M = Zr (1), Ti (2)) in 80% (1) and 75% (2) yields. This reaction involves an apparent cleavage of the >NCH2–ArOH bond (loss of the phenol in the ligand) and formation of the >NCH2–CH2Bn bond (gain of the benzyl group in the ligand). Structural characterization of 1 by X-ray diffraction analysis confirms that the complex formed is a bis(benzyl) complex of Zr coordinated by a newly derived tridentate amine-bis(phenoxy) ligand arranged in a mer configuration in the solid state. The abstractive activation of 1 and 2 with B(C6F5)3·THF in CD2Cl2 at room temperature generates the corresponding benzyl cations {BnCH2N[(2,4-tBu2C6H2(CH2)O]2MBn(THF)}+[BnB(C6F5)3]− (M = Zr (3), Ti, (4)). These cationic complexes, along with their analo...

A single phase molecular adduct, MgCl2�6CH3OH has been synthesized using MgCl2 and the simplest alcohol, methanol. Structural, spectroscopic, and morphological studies have been carried out for a better understanding of the single phase MgCl2�6CH 3OH adduct. 13C CPMAS solid state NMR studies show all six methanol molecules are magnetically equivalent and present in a single environment around the Mg2+ center. Raman spectral analysis of the characteristic peak at 708 cm-1 substantiates octahedral coordination of six CH3OH molecules around Mg2+. Solid state 13C NMR measurements, made after heat treatment at different temperatures, have been utilized to understand the variations in CH 3OH stoichiometry and coordination around Mg2+ with temperature. A titanated active catalyst, TiCl4 on MgCl 2�6CH3OH, has also been synthesized and subjected to detailed characterizations. The active catalyst shows high surface area (102 m2/g) and mesoporosity. The titanated catalyst has been screened for ethylene polymerization reactions using different cocatalysts (R3Al; R= -CH3CH2CH3, and -CH2CH(CH 3)2). A total of 7.25 kg of polyethylene per gram of catalyst has been obtained with Me3Al cocatalyst, which is six times higher in activity compared with commercial Me3Al/TiCl 4/MgCl2�6EtOH-supported catalyst. Although porosity influences the catalytic activity, other factors also seem to contribute to the total catalytic activity. � 2013 American Chemical Society.

A new and single phase molecular adduct of MgCl2 with six cyclohexanol molecules MgCl2�6C6H11OH (MgCyOH) has been synthesized. Structural insight to this adduct was obtained by a variety of physicochemical methods. 13C CPMAS spectrum and single pulse MAS spectra with high power proton decoupling recorded at different relaxation time showed the presence of two different sets of magnetically unequal cylcohexanol molecules present around Mg2+. A Raman feature of MgCyOH at 712 cm-1 confirms that cylcohexanol molecules are present around Mg2+ in an octahedral environment. MgCyOH has been used as support material to prepare Ziegler-Natta (Z-N) active catalyst. Textural property of above Z-N catalyst exhibits high surface area (236 m 2/g) with high porosity. Above active catalyst has been screened for ethylene polymerization. Depending on the cocatalyst employed (Me3Al, Et3Al, and iso-Bu3Al) and ethylene pressure, polyethylene yield varies an order of magnitude, from 378 to 3570 g/g catalyst, indicating a possible creation of different active sites and different interaction between cocatalyst and catalyst. � 2012 American Chemical Society.

Cu(OAc)2 was assessed to be a good catalyst for the bulk ring opening polymerization of lactides. These polymerizations are highly controlled leading to the formation of polymer with expected number average molecular weights and narrow molecular weight distribution. This method may be used to synthesize polymers with different end terminal groups. The over all process is green, since these polymers being biodegradable and the system is independent of solvents. � 2011 Elsevier B.V. All rights reserved.

Development and evaluation of in situ novel intragastric controlled-release formulation of hydrochlorothiazide In situ forming intragastric controlled-release formulation is a new technology in the field of oral controlled-release delivery systems. The objective of this study was to develop formulations that can control drug release up to 24 hours. In addition, a combination of appropriate polymers and solvents was selected that could form a drug loaded gel at the process temperature of 60-70 °C, which gel could turn into a rigid mass upon exposure to dissolution fluid at body temperature. The drug release mechanism from this rigid mass was controlled by different formulation factors such as different polymer grades, polymer concentrations, hydrophobicity or hydrophilicity of solvents, different drug loadings, and physicochemical properties of additional excipients. After evaluating different formulation factors, Ethocel 10 FP and triethyl citrate were selected for further studies using hydrochlorothiazide as a model drug. Polynomial correlation between viscosity of the blank gel and drug release profile was also obtained.

A series of aryloxy compounds and benzyloxy derivatives of Zr(IV) were synthesized in good yields and purity, employing the alcoholysis route. They were completely characterized with different spectroscopic techniques and single crystal X-ray diffraction. A high degree of fluxional behavior of these compounds was understood through variable-temperature NMR studies. X-ray diffraction studies prove that these compounds exist as dimers in the solid state. They are potent catalysts for the ring-opening polymerization of ?-caprolactone (CL) and ?-valerolactone (VL) resulting in high polymers with good number average molecular weights (Mn) and molecular weight distributions (MWDs). The degree of control in these polymerizations was found to be superior with the zirconium compounds when compared with the titanium analogues. The rate of polymerization was found to be slower for the zirconium compounds, as realized from kinetic studies. Analysis of the MALDI-TOF and 1H NMR spectra of low molecular weight oligomers of CL synthesized using these compounds reflect that these polymerizations proceed by the activated monomer mechanism. � 2010 Elsevier B.V. All rights reserved.

A variety of aromatic, aliphatic and conjugated alcohols were transformed to the corresponding carboxylic acids and ketones with a quantitative conversion in high yields with 70% t-BuOOH solution is water in the presence of catalytic amounts of La2O3. This method possesses a wide range of capabilities since it can be used with other functional groups which may not tolerate oxidative conditions, involves fairly simple method for work-up, exhibits chemoselectivity and proceeds under ambient conditions. The resulting products are obtained in good yields within reasonable time.

FeCl3�6H2O, RuCl3�H2O and FeCl2�4H2O are found to be bulk polymerization catalysts for the ring opening polymerization of ?-caprolactone, ?-valerolactone and ?-butyrolactone. These polymerizations can be significantly enhanced by conducting them in the presence of appropriate amounts of different alcohols. The major initiation pathway in the polymerization is found to proceed via the activated monomer mechanism and depending on the nature of the alcohol used, poly(lactones) with different end groups can be synthesized. Such polymerizations constitute an economical process, employing readily available inorganics as catalysts and do not necessitate solvents. The overall system is green and eco friendly. � 2008 Elsevier B.V. All rights reserved.

This contribution reports the first chemoselective, stereospecific, and living polymerization of polar divinyl monomers, enabled by chiral ansa-zirconocenium catalysts through an enantiomorphic-site controlled coordination-addition polymerization mechanism. Silyl-bridged-ansa-zirconocenium ester enolate 2 has been synthesized and structurally characterized, but it exhibits low to negligible activity and stereospecificity in the polymerization of polar divinyl monomers including vinyl methacrylate (VMA), allyl methacrylate (AMA), 4-vinylbenzyl methacrylate (VBMA), and N,N-diallyl acrylamide (DAA). In contrast, ethylene-bridged-ansa-zirconocenium ester enolate 1 is highly active and stereospecific in the polymerization of such monomers including AMA, VBMA, and DAA. The polymerization by 1 is perfectly chemoselective for all four polar divinyl monomers, proceeding exclusively through conjugate addition across the methacrylic C═C bond, while leaving the pendant C═C bonds intact. The polymerization of DAA is most stereospecific and controlled, producing essentially stereoperfect isotactic PDAA with [mmmm] > 99%, M(n) matching the theoretical value (thus a quantitative initiation efficiency), and a narrow molecular weight distribution (Đ = 1.06-1.16). The stereospecificity is slightly lower for the AMA polymerization but still leading to highly isotactic poly(allyl methacrylate) (PAMA) with 95-97% [mm]. The polymerization of VBMA is further less stereospecific, affording PVBMA with 90-94% [mm], while the polymerization VMA is least stereospecific. Several lines of evidence from both homo- and block copolymerization results have demonstrated living characteristics of the AMA polymerization by 1. Mechanistic studies of this polymerization have yielded a monometallic coordination-addition polymerization mechanism involving the eight-membered chelating intermediate. Post-functionalization of isotactic polymers bearing the pendant vinyl group on every repeating unit via the thiol-ene "click" reaction achieves a full conversion of all the pendant double bonds to the corresponding thioether bonds. Photocuring of such isotactic polymers is also successful, producing an elastic material readily characterizable by dynamic mechanical analysis.

A series of gallium and indium complexes containing a bis(imino)phenolate ligand framework were synthesized and completely characterized with different spectroscopic techniques. The molecular structures of a few complexes were determined using single crystal X-ray diffraction studies. These compounds were found to be extremely active towards the bulk ring opening polymerization (ROP) of lactides yielding polymers with high number average molecular weight (Mn) and controlled molecular weight distributions (MWDs). The neutral complexes 1-8 produce isotactic enriched poly(lactic acid) (PLA) from rac-lactide (rac-LA) under melt conditions, whereas the ionic complex 9 produces atactic PLA. The polymerizations are controlled, as evidenced by the narrow molecular distribution (MWDs) of the isolated polymers in addition to the linear nature of number average molecular weight (Mn) versus conversion plots with variations in monomer to catalyst ratios. The kinetic and mechanistic studies associated with these polymerizations have been performed. � The Royal Society of Chemistry 2015.

A variety of aromatic, aliphatic and conjugated aldehydes and alcohols were transformed to the corresponding carboxylic acids and ketones with a quantitative conversion in high yields with 70% t-BuOOH solution in water in the presence of catalytic amounts of ceric ammonium nitrate [Ce(NH4)2(NO3)6] (CAN) under room temperature conditions. The scope of our catalytic system is applicable for a wide range of aromatic, conjugated and aliphatic substrates. These aldehydes were converted to the corresponding carboxylic acids in good isolated yields in reasonable times. This method possesses a wide range of capabilities since it can be used with other functional groups which may not tolerate oxidative conditions, involves fairly simple method for work-up, exhibits chemoselectivity and proceeds under ambient conditions. The resulting products are obtained in good yields within reasonable time.

In the title compound, C(27)H(20)NO(3)P, the P atom exhibits a somewhat distorted PNO(3) tetra-hedral geometry, with the O-P-O angle for the binaphthyl fragment being 102.82 (6)°. The dihedral angle between the naphthyl ring systems is 59.00 (2)°. In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds generate R(2) (2)(8) loops.

Aromatic and aliphatic aldehydes are directly converted into the corresponding primary amides by treatment with hydroxylamine hydrochloride in the presence of catalytic amounts of FeCl3 in water.

A direct synthetic route for the transformation of aldehydes into primary amides in the presence of catalytic amounts of FeCl3 in water is described. A direct synthetic route for the transformation of aldehydes into primary amides in the presence of catalytic amounts of FeCl3 in water is described. Copyright � 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New phosphoroamidate compounds with 1,1?-Bi-2-napthol (binol) ligand were synthesized from the corresponding phosphorochloridate intermediates and benzyl amine or benzyl amine derivatives. They were completely characterized using different spectroscopic methods and single crystal X-ray diffraction studies. These compounds effectively catalyze the ring-opening polymerization of -caprolactone (CL) and l-lactide (LA). This methodology of polymer synthesis is green and environmental benign since phosphorus is a natural constituent of human anatomy and these polymers being completely biodegradable. � 2011 Elsevier B.V. All rights reserved.

Controlled hydrolysis of [Ti(O-2,4,6-Br 3C 6H 2) 2(O-iPr) 2] 2 with water results in the formation of the Ti-oxo cluster Ti 8O 24C 66H 58Br 24 (1). This compound has a very interesting cage structure. The crystal structure consists of centrosymmetric neutral octamers containing two planar Ti 4 layers, interlinked by four linear oxo-bridges. The four independent Ti atoms have three different coordination environments. The four unique Ti centers are rigidly coplanar, giving a unique configuration. The bridging oxygen atoms linking the two inversion-center related Ti atoms give a novel assemblage reminiscent of an inverse "cake-plate". Compound 1 is an active initiator for the polymerization of cyclic ester monomers and lactide resulting in polymers with moderate number average molecular weights (M n) and close to narrow molecular weight distribution (MWD). � 2011 Elsevier B.V. All rights reserved.

A variety of aromatic, aliphatic and conjugated aldehydes and alcohols were transformed to the corresponding carboxylic acids and ketones with a quantitative conversion in high yields with 70% t-BuOOH solution in water in the presence of catalytic amounts of ceric ammonium nitrate [Ce(NH 4) 2(NO 3) 6] (CAN) under room temperature conditions. The scope of our catalytic system is applicable for a wide range of aromatic, conjugated and aliphatic substrates. These aldehydes were converted to the corresponding carboxylic acids in good isolated yields in reasonable times. This method possesses a wide range of capabilities since it can be used with other functional groups which may not tolerate oxidative conditions, involves fairly simple method for work-up, exhibits chemoselectivity and proceeds under ambient conditions. The resulting products are obtained in good yields within reasonable time. � 2011 SIOC, CAS, Shanghai & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In the title molecular salt, C8H12N+·C6H10O4P−, the cation and anion are connected by N—H...O hydrogen bonds. The C atoms of the cyclohexane ring are disordered over two sets of sites in a 0.51 (4):0.49 (4) occupancy ratio to generate two superimposed chair conformations. One of the terminal phosphate O atoms is also disordered in a 0.62 (2):0.38 (2) ratio.

Bis(imino)phenoxide complexes of zirconium possess spectacular reactivity towards the solvent-free polymerization of cyclic ester monomers and lactides. Polymerization of lactide is living and the resulting product has exceptionally high number average molecular weights (Mn). Polymerization of ?-butyrolactone gives syndiotactic poly(3-hydroxybutyrate) with good M n and molecular weight distribution (MWD). � The Royal Society of Chemistry 2010.

A variety of aromatic, aliphatic and conjugated aldehydes were converted to the corresponding carboxylic acid derivatives with 30% H2O2 as the oxidant in the presence of catalytic amounts of AgNO3. The method described has wide range of applicabilities, does not involve cumbersome work-up, exhibits chemoselectivity and proceeds under mild reaction conditions, and the resulting products are obtained in good yields within reasonable time.

A large variety of aryloxy compounds and benzyloxy derivatives of Hf(IV) were synthesized from Hf(O- t Bu) 4 using the alcoholysis route. These compounds were completely characterized using various spectroscopic and analytical methods along with single crystal X-ray diffraction studies. Multinuclear NMR studies prove high degree of fluxional behavior of these compounds in solution. They adopt a dimeric structure in the solid-state as seen from X-ray diffraction studies on a few of them. These compounds are powerful catalysts for the ring-opening polymerization of e -caprolactone (CL) and δ -valerolactone (VL) resulting in high number average molecular weight ( M n ) polymers and controlled molecular weight distributions (MWDs). Significant control in the polymerization was achieved with these compounds as initiators in comparison to their titanium and zirconium analogues. Kinetic studies reveal that the rates of such polymerizations are in general slower than the corresponding titanium and zirconium derivatives. 1 H NMR and MALDI-TOF studies of low molecular weight oligomers suggest that these polymerizations proceed by the activated monomer mechanism.

Zn(OAc) 2�2H 2O is found to be an effective bulk polymerization catalyst for the ring-opening polymerization of rac-lactide, l-lactide, ?-caprolactone and ?-valerolactone. The propensity of polymerizations can be enhanced by performing them in the presence of appropriate amounts of different alcohols. The major initiation pathway in the polymerization is found to proceed via the activated monomer mechanism and depending on the nature of the alcohol used, polymers with different end groups can be synthesized. These polymerization system constitutes an economical process, employing readily available inorganics such as Zn(OAc) 2�2H 2O as catalyst and do not necessitate solvents. The overall system is green and eco friendly. � 2010 Elsevier B.V.

A variety of aromatic, aliphatic and conjugated aldehydes were converted to the corresponding carboxylic acid derivatives with 30% H2O 2 as the oxidant in the presence of catalytic amounts of AgNO 3. The method described has wide range of applicabilities, does not involve cumbersome work-up, exhibits chemoselectivity and proceeds under mild reaction conditions, and the resulting products are obtained in good yields within reasonable time. � 2009 Elsevier Ltd. All rights reserved.

A variety of aryloxy compounds and benzyloxy derivatives of TiIV were synthesized from Ti(iPrO)4 using the alcoholysis route. These compounds were characterized using various analytical methods and single-crystal X-ray diffraction. Multinuclear NMR studies prove high degree of fluxional behavior of these compounds in solution. They adopt a dimeric structure in the solid state as seen from X-ray diffraction studies on a few of them. These compounds are powerful catalysts for the ring-opening polymerization of ϵ-caprolactone (CL) and δ-valerolactone (VL) resulting in high polymers with good number average molecular weights (Mn). Significant control can be achieved by performing such polymerizations in the presence of benzyl alcohol (BnOH). This is reflected by higher Mn and much narrower molecular weight distributions (MWDs) of the resulting polymers. Kinetic studies reveal that the rates of such polymerizations are much higher in the presence of BnOH. 1H NMR and MALDI-TOF studies of low molecular weight oligomers suggest that these polymerizations proceed by the activated monomer mechanism in the presence of BnOH. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

An efficient, high-yielding route to β-methyl-α-methylene-γ-butyrolactone (βMMBL)—a monomer for the production of high-performance engineering bioplastics—from biorenewable and inexpensive itaconic acid has been developed. The monomer prepared by this new route is of high purity as isolated without purification, as evidenced by NMR as well as small and large-scale polymerization tests.

Protonolysis of M(Bn)4 (M = Zr, Ti; Bn = benzyl) with equimolar 2,4-di-tert-butyl-6-[(2,6-diisopropylphenylimino)methyl]phenol [(2,6-(i)Pr2C6H3)N=C(3,5-(t)Bu2C6H2)OH] in toluene at -30 °C to 25 °C cleanly affords the corresponding achiral (imino)phenoxy-tribenzyl complexes, [(2,6-(i)Pr2C6H3)N=C(3,5-(t)Bu2C6H2)O]Zr(Bn)3 (1) and [(2,6-(i)Pr2C6H3)N=C(3,5-(t)Bu2C6H2)O]Ti(Bn)3 (2). A chiral dibenzyl complex 3 incorporating the unsymmetric, tetradentate amino(imino)bis(phenoxy) ligand, [2,4-Br2C6H2(O)(6-CH2(NC5H9))CH2N=CH(2-adamantyl-4-MeC6H2O)]Zr(Bn)2 (3), has also been prepared using the same protonolysis protocol. Abstractive activation of 1 with B(C6F5)3·THF in CD2Cl2 at room temperature (RT) affords clean, quantitative formation of the corresponding zirconium cation [((2,6-(i)Pr2C6H3)N=C(3,5-(t)Bu2C6H2)O)Zr(Bn)2(THF)](+)[BnB(C6F5)3](-) (4). Likewise, benzyl abstraction of 2 with B(C6F5)3·THF in CD2Cl2 at RT generates the cationic titanium complex [((2,6-(i)Pr2C6H3)N=C(3,5-(t)Bu2C6H2)O)Ti(Bn)2(THF)](+)[BnB(C6F5)3](-) (5), accompanied by a small amount of decomposed species as a result of C6F5 transfer. The dibenzyl cations 4 and 5 have been characterized spectroscopically, and their structures have been confirmed by single crystal X-ray diffraction analysis. Characteristics of the coordination polymerization of renewable α-methylene-γ-butyrolactone monomers by the cationic catalysts derived from achiral complexes 1 and 2 as well as chiral complex 3 have been investigated, representing the first study of such polymerization by non-metallocene catalysts.

In the crystal structure of the title compound, C(6)H(16)N(+)·C(20)H(12)O(4)P(-), an N-H⋯O inter-action links the cation to the anion. The N atom in the triethyl-ammonium cation exhibits a trigonal-bipyramidal coordination geometry and forms an N-H⋯O inter-action with one phosphate O atom of the 1,1'-binaphthyl-2,2'-diyl phosphate ligand. A bifurcated C-H⋯O inter-action with the other phosphate O atom links molecules along the a axis. The dihedral angle between the two naphthyl ring systems is 58.92 (3)°. The refined Flack parameter value of 0.50 (10) indicates inversion twinning.