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Chemotherapy often involves broad-spectrum cytotoxic agents with many side effects and limited targeting. Corroles are a class of tetrapyrrolic macrocycles that exhibit differential cytostatic and cytotoxic properties in specific cell lines, depending on the identities of the chelated metal and functional groups. The unique behavior of functionalized corroles towards specific cell lines introduces the possibility of targeted chemotherapy. Many anticancer drugs are evaluated by their ability to inhibit RNA transcription. Here we present a step-by-step protocol for RNA transcription in the presence of known and potential inhibitors. The evaluation of the RNA products of the transcription reaction by gel electrophoresis and UVVis spectroscopy provides information on inhibitive properties of potential anticancer drug candidates and, with modifications to the assay, more about their mechanism of action. Little is known about the molecular mechanism of action of corrole cytotoxicity. In this experiment, we consider two corrole compounds: gallium(III) 5,10,15-(tris)pentafluorophenylcorrole (Ga(tpfc)) and freebase analogue 5,10,15-(tris)pentafluorophenylcorrole (tpfc). An RNA transcription assay was used to examine the inhibitive properties of the corroles. Five transcription reactions were prepared: DNA treated with Actinomycin D, triptolide, Ga(tpfc), tpfc at a [complex]:[template DNA base] ratio of 0.01, respectively, and an untreated control. The transcription reactions were analyzed after 4 hr using agarose gel electrophoresis and UV-Vis spectroscopy. There is clear inhibition by Ga(tpfc), Actinomycin D, and triptolide. This RNA transcription assay can be modified to provide more mechanistic detail by varying the concentrations of the anticancer complex, DNA, or polymerase enzyme, or by incubating the DNA or polymerase with the complexes prior to RNA transcription; these modifications would differentiate between an inhibition mechanism involving the DNA or the enzyme. Adding the complex after RNA transcription can be used to test whether the complexes degrade or hydrolyze the RNA. This assay can also be used to study additional anticancer candidates.

Z-Selective cross metathesis of allylic-substituted olefins is explored with recently developed ruthenium-based metathesis catalysts., The Z-selective cross metathesis of allylic-substituted olefins is explored with recently developed ruthenium-based metathesis catalysts. The reaction proceeds with excellent stereoselectivity for the Z-isomer (typically >95%) and yields of up to 88% for a variety of allylic substituents. This includes the first synthesis of Z-α,β-unsaturated acetals by cross metathesis and their elaboration to Z-α,β-unsaturated aldehydes. In addition, the reaction is tolerant of a variety of cross partners, varying in functionality and steric profile.

A stereoselective synthesis of anti-1,2-diols has been developed using a multitasking Ru-catalyst in an assisted tandem catalysis protocol. A cyclometalated ruthenium complex catalyzes first a Z-selective cross metathesis of two terminal olefins followed by a stereospecific dihydroxylation. Both steps are catalyzed by Ru, as the Ru-complex is converted to a dihydroxylation catalyst upon addition of NaIO4. A variety of olefins are transformed into valuable highly functionalized and stereodefined molecules. Mechanistic experiments are performed to probe the nature of the oxidation step and catalyst inhibition pathways. These experiments point the way to more broadly applicable tandem catalytic transformations.

The title procedure under conditions A) renders possible a rapid and successful access to the desired ketones.

A new synthetic route to cyclic polymers has been developed in which the ends of growing polymer chains remain attached to a metal complex throughout the entire polymerization process. The approach eliminates the need for linear polymeric precursors and high dilution, drawbacks of traditional macrocyclization strategies, and it effectively removes the barrier to producing large quantities of pure cyclic material. Ultimately, the strategy offers facile access to a unique macromolecular scaffold that may be used to meet the increasing demand of new applications for commercial polymers. As a demonstration of its potential utility, cyclic polyethylenes were prepared and found to exhibit a variety of physical properties that were distinguishable from their linear analogs.

Neutral Ni(II) salicylaldimine catalysts (pendant ligand NCMe or PPh3) were used to copolymerize ethylene with monomers containing esters, alcohols, anhydrides, and amides and yielded linear functionalized polyethylene in a single step. -Olefins and polycyclic olefin comonomers carrying functionality were directly incorporated into the polyethylene backbone by the catalysts without any cocatalyst, catalyst initiator, or other disturber compounds. The degree of comonomer incorporation was related to the monomer structure: tricyclononenes norbornenes -olefins. A wide range of comonomer incorporation, up to 30 mol %, was achieved while a linear polyethylene structure was maintained under mild conditions (40 °C, 100 psi ethylene). Results from the characterization of the copolymers by solution and solid-state NMR techniques, thermal analysis, and molecular weight demonstrated that the materials contained a relatively pure microstructure for a functionalized polyethylene that was prepared in one step with no catalyst additive. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2842–2854, 2002

Three metal-catalyzed vinyl addition copolymers derived from partially fluorinated norbornenes and tricyclononenes have been synthesized and evaluated for use in formulating photoresists for 157 nm lithography imaging. The transparency of these polymers at 157 nm, as measured by variable angle spectroscopic ellipsometry (VASE), is greatly improved over their nonfluorinated counterparts. The results of preliminary lithographic evaluations of resists formulated from these polymers alone and with the addition of several new fluorinated dissolution inhibitors are presented. Images as small as 70 nm have been printed in some formulations.

The synthesis of a new methylene−(vinyl alcohol) copolymer, poly((vinyl alcohol)_2-alt-methylene) (MVOH), by ring-opening metathesis polymerization with ruthenium catalysts is reported. Unsaturated cyclic 1,3-diols were protected with a di-tert-butylsilyl group to form strained cyclic olefins. The molecular weights of the polymers were controlled by varying the monomer-to-catalyst ratios or by the addition of a chain transfer agent. Hydrogenation and subsequent deprotection of the ROMP polymers yield the MVOH copolymer structure which was confirmed by ^1H NMR and ^(13)C NMR spectroscopies. Thermal properties of the corresponding MVOH copolymer are reported.

Two new synthetic routes to pterulone, a fungal metabolite possessing potent antifungal activity as an inhibitor of NADH/ubiquinone oxidoreductase, are reported. (C) 2002 Elsevier Science Ltd. All rights reserved.

[reaction: see text] Trisubstituted alkenes have been prepared via intermolecular olefin cross-metathesis (CM) between alpha-olefins and symmetrically 1,1-disubstituted olefins using an imidazolylidene ruthenium benzylidene complex. Of particular interest is the synthesis of isoprenoid/prenyl groups by a simple solvent-free CM reaction with isobutylene. In addition, prenyl groups can also be installed by a cross-metathesis of 2-methyl-2-butene with a variety of alpha-olefins at room temperature with low catalyst loadings.

Ronald Breslow, Samuel Latham Mitchill Professor of Chemistry at Columbia University, passed away on October 25, 2017, at the age of 86. Breslow made remarkable contributions to the fields of physical-organic and bioorganic chemistry, including biological and biomimetic transformations, and the use of molecular recognition to control reaction selectivity.

Arrays of vapor detectors have been formed through addition of varying mass fractions of the plasticizer diethylene glycol dibenzoate to carbon black-polymer composites of poly(vinyl acetate) (PVAc) or of poly(N-vinylpyrrolidone). Addition of plasticizer in 5% mass fraction increments produced 20 compositionally different detectors from each polymer composite. Differences in vapor sorption and permeability that effected changes in the dc electrical resistance response of these compositionally different detectors allowed identification and classification of various test analytes using standard chemometric methods. Glass transition temperatures, T_g, were measured using differential scanning calorimetry for plasticized polymers having a mass fraction of 0, 0.10, 0.20, 0.30, 0.40, or 0.50 of plasticizer in the composite. The plasticized PVAc composites with T_g < 25 °C showed rapid responses at room temperature to all of the test analyte vapors studied in this work, whereas composites with T_g > 25 °C showed response times that were highly dependent on the polymer/analyte combination. These composites showed a discontinuity in the temperature dependence of their resistance, and this discontinuity provided a simple method for determining the T_g of the composite and for determining the temperature or plasticizer mass fraction above which rapid resistance responses could be obtained for all members of the test set of analyte vapors. The plasticization approach provides a method for achieving rapid detector response times as well as for producing a large number of chemically different vapor detectors from a limited number of initial chemical feedstocks.

Ruthenium-catalyzed olefin cross-metathesis tolerates a wide range of functional groups, including phosphine-boranes, sulfides, amines, phenols, and oxazolines. The high functional group tolerance allows for the use of an olefin as a linchpin for the synthesis of a variety of bi-, tri-, and tetradentate chiral ligands with a high degree of functional group diversity. The increasing necessity for the synthesis of diverse libraries of compounds demands the development of methods that tolerate a wide range of functional groups. The formation of carbon-carbon bonds by olefin metathesis (1) offers a powerful method for the creation of chemical diversity (2). In particular, olefin cross-metathesis (CM) can provide access to alkenes bearing a wide range of functional groups (3). However, the reaction has generally been limited to olefins in which functional groups that may behave as ligands for the catalyst are absent. Herein are detailed our studies on the use of heteroatom containing olefins in the cross-metathesis reaction and applications of this method to the generation of a variety of 2-oxazolylphenol-derived tridentate chiral ligands. The study was initiated by the observation that ruthenium catalyst 1 readily catalyzed the ring- closing metathesis (RCM) of diallyl disulfide to afford cyclic disulfide 2 in 90% yield. This result is in sharp contrast to the first-generation bis-phosphine catalyst ((PCy 3 ) 2 Ru(CHPh)Cl 2 ), which was shown to be completely unreactive in this transformation (4). This observation prompted us to explore the pos- sibility that catalyst 1 may tolerate olefins bearing functional groups that were poor substrates for the first-generation catalyst. To this end, allyl methyl sulfide was reacted with 5 mol% 1 to afford the dis- ubstituted olefin 3 in 69% yield as a 6:1 mixture of E:Z olefin isomers (5).

A PNP-pincer iridium dihydride performs the H/D exchange between aromatic substrates and tertiary hydrosilanes and D_(2)O or C_(6)D_(6). Complete incorporation of deuterium into sterically accessible C_(ar)–H and Si–H bonds was observed at a moderate temperature of 80 °C.

The cross-metathesis of terminal olefins using a novel ruthenium catalyst results in excellent selectivity for the Z-olefin homodimer. The reaction was found to tolerate a large number of functional groups, solvents, and temperatures while maintaining excellent Z-selectivity, even at high reaction conversions.

Olefin cross metathesis is a particularly powerful transformation that has been exploited extensively for the formation of complex products. Until recently, however, constructing Z-olefins using this methodology was not possible. With the discovery and development of three families of ruthenium-based Z-selective catalysts, the formation of Z-olefins using metathesis is now not only possible but becoming increasingly prevalent in the literature. In particular, ruthenium complexes containing cyclometalated NHC architectures developed in our group have been shown to catalyze various cross metathesis reactions with high activity and, in most cases, near perfect selectivity for the Z-isomer. The types of cross metathesis reactions investigated thus far are presented here and explored in depth.

© 2014 The Authors BJU International © 2014 BJU International Published by John Wiley & Sons Ltd. Kidney stone disease is endemic. Extracorporeal shockwave lithotripsy was the first major technological breakthrough where focused shockwaves were used to fragment stones in the kidney or ureter. The shockwaves induced the formation of cavitation bubbles, whose collapse released energy at the stone, and the energy fragmented the kidney stones into pieces small enough to be passed spontaneously. Can the concept of microbubbles be used without the bulky machine? The logical progression was to manufacture these powerful microbubbles ex vivo and inject these bubbles directly into the collecting system. An external source can be used to induce cavitation once the microbubbles are at their target; the key is targeting these microbubbles to specifically bind to kidney stones. Two important observations have been established: (i) bisphosphonates attach to hydroxyapatite crystals with high affinity; and (ii) there is substantial hydroxyapatite in most kidney stones. The microbubbles can be equipped with bisphosphonate tags to specifically target kidney stones. These bubbles will preferentially bind to the stone and not surrounding tissue, reducing collateral damage. Ultrasound or another suitable form of energy is then applied causing the microbubbles to induce cavitation and fragment the stones. This can be used as an adjunct to ureteroscopy or percutaneous lithotripsy to aid in fragmentation. Randall's plaques, which also contain hydroxyapatite crystals, can also be targeted to pre-emptively destroy these stone precursors. Additionally, targeted microbubbles can aid in kidney stone diagnostics by virtue of being used as an adjunct to traditional imaging methods, especially useful in high-risk patient populations. This novel application of targeted microbubble technology not only represents the next frontier in minimally invasive stone surgery, but a platform technology for other areas of medicine.

A series of cyclometalated Z-selective ruthenium olefin metathesis catalysts with alterations to the N-heterocyclic carbene (NHC) ligand were prepared. X-Ray crystal structures of several new catalysts were obtained, elucidating the structural features of this class of cyclometalated complexes. The metathesis activity of each stable complex was evaluated, and one catalyst, bearing geminal dimethyl backbone substitution, was found to be comparable to our best Z-selective metathesis catalyst to date.

A series of cyclometalated Z-selective ruthenium olefin metathesis catalysts with alterations to the N-heterocyclic carbene (NHC) ligand were prepared. X-Ray crystal structures of several new catalysts were obtained, elucidating the structural features of this class of cyclometalated complexes. The metathesis activity of each stable complex was evaluated, and one catalyst, bearing geminal dimethyl backbone substitution, was found to be comparable to our best Z-selective metathesis catalyst to date.

The success of enantioselective olefin metathesis relies on the design of enantioenriched alkylidene complexes capable of transferring stereochemical information from the catalyst structure to the reactants. Cyclometalation of the NHC ligand has proven to be a successful strategy to incorporate stereogenic atoms into the catalyst structure. Enantioenriched complexes incorporating this design element catalyze highly Z- and enantioselective asymmetric ring opening/cross metathesis (AROCM) of norbornenes and cyclobutenes, and the difference in ring strain between these two substrates leads to different propagating species in the catalytic cycle. Asymmetric ring closing metathesis (ARCM) of a challenging class of prochiral trienes has also been achieved. The extent of reversibility and effect of reaction setup was also explored. Finally, promising levels of enantioselectivity in an unprecedented Z-selective asymmetric cross metathesis (ACM) of a prochiral 1,4-diene was demonstrated.

The utility of this reaction is demonstrated by a short synthesis of L-ribose derivative (VII).

The aldehyde-selective oxidation of alkenes bearing diverse oxygen groups in the allylic and homoallylic position was accomplished with a nitrite-modified Wacker oxidation. Readily available oxygenated alkenes were oxidized in up to 88% aldehyde yield and as high as 97% aldehyde selectivity. The aldehyde-selective oxidation enabled the rapid, enantioselective synthesis of an important pharmaceutical agent, atomoxetine. Finally, the influence of proximal functional groups on this anti-Markovnikov reaction was explored, providing important preliminary mechanistic insight.

The decarbonylative dehydration of fatty acids shows a good functional group tolerance and provides linear alpha olefins with only small amounts of internal olefins as side products.

A new strategy to access linear amines from terminal olefin precursors is reported. This two-step, one-pot hydroamination methodology employs sequential oxidation and reduction catalytic cycles. The formal hydroamination transformation proceeds with excellent regioselectivity, and only the anti-Markovnikov product is observed. Up to 70% yield can be obtained from styrenes or aliphatic olefins and either primary or secondary aromatic amines. Additionally, the scope is broad with respect to the olefin and accommodates a variety of functionalities; we demonstrate that amines with removable aryl protecting groups may be utilized to allow access to a more diverse array of hydroamination adducts.

[reaction: see text] The selective ring opening cross metathesis of 1,5-cyclooctadiene and trisubstituted cycloolefins with acroyl species is described. The ring-opened products contain electronically differentiated olefins suitable for additional metathesis reactions. Trisubstituted cycloolefins open regioselectively, placing the acroyl cap on the less-substituted terminus.

Tp(PPh_3)Ru(η^2-O_2CCHPh_2) (1) [Tp = tris(pyrazolyl)borate] has been prepared by the reaction of TpRu(Cl)(PPh_3)_2 with 1.2 equiv of NaO_2CCHPh_2. Complex 1 reacts with diphenylcyclopropene to generate the metallacycle Tp(PPh_3)Ru[κ^2-(C,Ο)-C(═CHCHPh_2)OC(CHPh_2)═O] (2). A trace of the carbene Tp(PPh_3)(η^1-O_2CCHPh_2)Ru═CHCH═C(Ph)_2 (3) is also observed in the crude reaction mixture. Compound 1 reacts with phenyldiazomethane to form the benzylidene Tp(PPh_3)(η^1-O_2CCHPh_2)Ru═CHPh (4). A similar species is also available by the reaction between AgO_2CCHPh_2 and Tp(PCy_3)(Cl)Ru═CHCH═C(CH_3)_2 (5), which affords Tp(PCy_3)(η^1-O_2CCHPh_2)Ru═CHCH═C(CH_3)_2 (6). With the addition of an excess of HCl, complexes 4 and 6 release free HO_2CCHPh_2 and are converted to Tp(PPh_3)(Cl)Ru═CHPh (7) and complex 5, respectively. The reaction of 1 with phenylacetylene yields the five-membered chelate Tp(PPh_3)Ru[κ^2-(C,Ο)-C(═CHPh)OC(CHPh_2)═O] (8). Complex 8 is also formed in the reaction of Tp(PPh_3)(Cl)Ru═C═CHPh with 1.2 equiv of AgO_2CCHPh_2. Compounds 1, 2, and 8 have been characterized by X-ray crystallography. Complexes 2, 5, 6, 7, and 8 do not catalyze olefin metathesis reactions, while 4 is an active initiator for the ring-opening metathesis polymerization of norbornene.

The area of highly conjugated organic polymers has commanded interest for quite some time. Polyacetylene (PA) is the (structurally) simplest conjugated organic polymer; however, its intractable nature has made its characterization quite difficult. The first successful PA film was produced in 1971 by Shirakawa and Ikeda from acetylene monomer and a highly concentrated Ziegler–Natta catalyst. Over the last 30 years, several methods have been introduced which allow for the synthesis of a pre-cursor polymer that can subsequently be transformed into PA. Unfortunately, many of these techniques either involve the extrusion of large molecular fragments that can limit the processing of these polymers or produce very sensitive and even explosive materials. Therefore, a forgiving and direct route to PA and substituted PA, such as ring opening metathesis polymerization (ROMP), which might lead to new substrates and amenable processing conditions is worth pursuing. The metathesis polymerization of 1,3,5,7-cyclooctatetraene (COT) has been reported previously, however, the only successful routes to date have focused on early transition metal catalysts (tungsten) which are sensitive to air, moisture, and functional groups. It would be advantageous to use a late transition metal catalyst (ruthenium) which is more tolerant towards air, moisture and functional groups. Unfortunately, the RuCl_2(☐CHPh)(PCy_3)_2, catalyst 1, was not able to polymerize COT presumably due to its lower activity. Here, we report the ROMP of COT by a highly active well defined ruthenium olefin metathesis catalyst, RuCl_2(☐CHPh)(PCy_3)(IMesH_2), catalyst 2, to produce films of polyacetylene (PA) with conductivities comparable to those first produced by Shirakawa.

The enhanced metathesis activity of 1,3-dimesityl-4,5-dihydroimidazole-2-ylidene ruthenium carbene catalyst 3 significantly increases the feasibility of synthesizing macrocyclic compounds. Catalyst 3 exhibits sufficient activity in RCM to dimerize alpha,beta-unsaturated ester substrates and afford the corresponding head-to-tail (E,E)-dimeric (and trimeric) macrocycles. The dimerization appears to be under thermodynamic control with the product mixture dependent not only on the electronic and steric nature of the substrate but also on concentration.

[reaction: see text] The first enantioselective ruthenium olefin metathesis catalysts have been prepared, and high enantiomeric excesses (up to 90%) are observed in the desymmetrization of achiral trienes. A model consistent with the stereochemical outcome of the reactions is described and suggests side-on olefin binding and reorganization of the halide ligands.

Heptapeptides containing residues with terminal olefin-derivatized side chains (3 and 4) have been treated with ruthenium alkylidene 1 and undergone facile ring-closing olefin metathesis (RCM) to give 21- and 23-membered macrocyclic peptides (5 and 6). The primary structures of peptides 3 and 4 were based upon a previously studied heptapeptide (2), which was shown to adopt a predominantly 3(10)-helical conformation in CDCl(3) solution and an alpha-helical conformation in the solid state. Circular dichroism, IR, and solution-phase (1)H NMR studies strongly suggested that acyclic precursors 3 and 4 and the fully saturated macrocyclic products 7 and 8 also adopted helical conformations in apolar organic solvents. Single-crystal X-ray diffraction of cyclic peptide 8 showed it to exist as a right-handed 3(10)-helix up to the fifth residue. Solution-phase NMR structures of both acyclic peptide 4 and cyclic peptide 8 in CD(2)Cl(2) indicated that the acyclic diene assumes a loosely 3(10)-helical conformation, which is considerably rigidified upon macrocyclization. The relative ease of introducing carbon-carbon bonds into peptide secondary structures by RCM and the predicted metabolic stability of these bonds renders olefin metathesis an exceptional methodology for the synthesis of rigidified peptide architectures.

Bis(acetoxy)-terminated telechelic poly(butadiene) (PBD) with molecular weights controllable up to 3.0×10 4 have been prepared via the ring-opening metathesis polymerization (ROMP) of cyclooctadiene when 1,4-bis(acetoxy)-2-butene was included as a chain transfer agent (CTA). The polymerizations were catalyzed by a highly active ruthenium catalyst 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene) (PCp 3 )(Cl 2 Ru=CHCHC(CH 3 ) 2 (Cp=cyclopentyl) ( 6 ) with monomer/catalyst ratios as high as 9.8×10 4 . Removal of the acetoxy groups with sodium hydroxide afforded hydroxy end-terminated telechelic PBD (HTPBD). Examination of the telechelic PBDs revealed an exclusive 1,4-PBD microstructure with a predominately trans geometry (up to 90%). The high activity and stability of 6 permitted a one-step synthesis of HTPBD using the unprotected free alcohol, 2-butene-1,4-diol, as the CTA.

The crystal structures of novel products from the insertion of various diazoalkanes into the iron−phosphorus bond in FeCl_2L_2 (L = phosphine) complexes are presented. Specifically, ethyl diazoacetate and diphenyldiazomethane reacted with FeCl_2(PMe_2Ph)_2 to afford FeCl_2[N(PMe_2Ph)NC(H)CO_2Et]_2 (1) and FeCl_2[N(PMe_2Ph)NCPh_2] (2). Interestingly, ethyl diazoacetate inserted into both iron phosphine bonds of FeCl_2(d^ippe)_2 to afford the seven-membered metallacycle FeCl_2{N[NC(H)CO_2Et]P^iPr)_2CH_2CH_2P(^iPPr)_2N[NC(H)CO_2Et]}_2 (3).

Fluorocarbon polymers and siloxane-based polymers have been identified as promising resist candidates for 157nm material design because of their relatively high transparency at this wavelength. This paper reports our recent progress toward developing 157nm resist materials based on the first of these two polymer systems. Polymers based on fluorinated norbornenes have been prepared and preliminary imaging studies at 157nm are described. Functional norbornenes having α-trifluoromethyl groups could not be polymerized by either Ni(II) or Pd(II) catalysts. Several new approaches to incorporating these transparent monomers into functional polymers have been investigated and are described. The lithographic performance of some of these polymers is discussed.

Aim: To determine if residual cylindrical refractive error after cataract surgery can be adjusted using the light-adjustable lens (LAL). Methods: The LAL is a photosensitive silicone intraocular lens whose power can be adjusted post-operatively using UV light at 365 nm. A digital light delivery device (DLD) is used to adjust LAL power in situ to correct residual refractive errors non-invasively. Profiles developed to correct residual cylindrical and spherical errors were tested on five patients, with postoperative toric refractive errors of 1.25–1.75 D. At 2 weeks post-implantation, best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA) and residual refractive errors were measured. Results: Toric error was reduced in each of the patients and refractions remained stable for the 9 month follow-up period. Achieved spherical equivalent manifest refraction (MRSE) was within 0.25 D of targeted emmetropia. All five patients improved their UCVA to ≥ 20/25 (≤ 0.1 logarithm of the minimum angle of resolution (LogMAR)) and maintained their BCVA. Conclusion: The LAL can be adjusted postoperatively to correct residual astigmatism.

Synthetic norbornenyl polymers with pendent cell adhesive sequences glycine-arginine-glycine-aspartic acid (GRGD) and serine-arginine-asparagine (SRN) were synthesized by ring-opening metathesis polymerization (ROMP) using newly developed ruthenium initiators. Initially, simpler polymers with pendent glycine, alanine, or penta(ethylene glycol) (EO_5) units attached directly or through ethyl and propyl spacers to various norbornenyl backbones were synthesized using Ru CHPh(Cl)_2(PCy_3)_2 (1) as the initiator. The molecular weights, PDI's, polymerization times, yields, and glass transition temperatures were compared for these polymers. As a result of this comparison, poly(5-norbornene-2-carboxyl) was chosen as the backbone for the more complex oligopeptide containing polymers, and norbornene monomers with pendent EO_5 (21), GRGD (24), and SRN (25) units were made. Monomers 21 and 24 were copolymerized to form a poly(norbornene) containing 9.2 mol % GRGD (26a) using 1 as the initiator. However, incorporating larger amounts of GRGD resulted in extremely low yields of polymers that exhibited bimodal molecular weight distributions. Homopolymers and copolymers with larger amounts of GRGD and SRN were synthesized in good yields (32−92%) with monomodal molecular weight distributions using the newly developed, more active, 2,3-dihydroimidazolylidene initiators, Ru CHPh(Cl)_2(PCy_3)(DHIMes) (2) and Ru CH−CH C(CH_3)_2(Cl)_2(PCp_3)(DHIMes) (3). In this way, EO_5 containing copolymers with 49 mol % GRGD (26b), 53 mol % SRN (27b), or 32 mol % GRGD and 21 mol % SRN (28a) were synthesized, as well as copolymer 28b with 53 mol % GRGD and 47 mol % SRN. To alter the presentation of the GRGD, an EO_5 containing copolymer with a propyl spacer between the GRGD and the backbone (30) was also synthesized.

Ruthenium alkylidenes 6 and 7 bearing cationically functionalized phosphine ligands are soluble and stable in protic solvents and initiate olefin metathesis reactions in methanol, water, and aqueous emulsions. NMR spectroscopy data and X-ray diffraction analyses of alkylidene 6 suggested that these new alkylidenes were structurally similar to previously reported complexes of the type (PR_3)_2Cl_2Ru ═ CHR, in which the alkylidene substituents lie in the Cl−Ru−Cl plane. The anionic chloride ligands of complexes 6 and 7 were found to undergo facile ligand exchange reactions with other anions in protic solution. Both alkylidenes initiate the ring-opening metathesis polymerization (ROMP) of strained, cyclic olefins in water. However, the propagating species in these reactions decompose prior to complete consumption of monomer. These complexes initiate the quantitative, living polymerization of functionalized monomers in water in the presence of a Brønsted acid. Both chain termination and chain transfer reactions were experimentally demonstrated to be absent on the time scale of these acid-activated polymerizations. Alkylidenes 6 and 7 react readily with acyclic olefins: alkylidene 6 reacted with trans-2-butene to yield a new ethylidene complex in either methanol or water, and the treatment of 6 with tri(ethylene glycol) methyl vinyl ether in water yielded water-soluble Fischer−carbene complex 16.

A series of ester-carbene complexes was synthesized. These complexes were found to be highly active for the metathesis of olefinic substrates, including acrylates and trisubstituted olefins. In addition, the ester-carbene moiety is thermodynamically high in energy. As a result, these complexes react to ring-open cyclohexene by metathesis to alleviate the thermodynamic strain of the ester-carbene ligand.

New hole transport polymers have been prepared through copolymerization of a fluorinated triphenyl diamine derivative and trimethoxyvinylsilane. The modification with trimethoxysilane groups has resulted in materials which can be cross-linked through hydrolysis and are capable of forming covalent chemical bonds to oxidic surfaces. Organic light-emitting diodes containing these polymers show decreased operating voltages and enhanced operational stability due to improved interfacial contact between the hole transport layer and the anode.

The synthesis of ring-opening metathesis polymerization (ROMP) chain transfer agents (CTA)s bearing methacrylate or epoxide end functionality was accomplished. In the presence of these CTAs, the ROMP of cyclooctadiene (COD) initiated with (PCy_3)_2Cl_2Ru CHPh afforded the respective telechelic poly(butenylene)s with either methacrylate or epoxide end groups. Control over the polymer molecular weight was demonstrated by varying the COD/CTA ratio. Successful cross-linking by thermal or photochemical initiation of the bis(methacrylate)-functionalized telechelic poly(butenylene)s or through acid catalysis of the bis(epoxide)-functionalized telechelic poly(butenylene)s was accomplished. While cross-linking was found to reduce solubility of the polymers, it greatly enhanced their thermal stability.

An organic electroluminescent device with a luminous efficiency of 20 Im/W, at 14 cd/m/sup 2/, and an external quantum efficiency of 4.6% has been fabricated using a high T/sub g/ hole transport polymer, a small molecule emission layer, and a LiF/Al cathode. The device quantum efficiency can be increased by tuning the ionization potential of the hole-transport moieties. When tested under pulsed voltage mode, in air at room temperature, and without any encapsulation, the device showed a high peak brightness of 4.4/spl times/10/sup 6/ cd/m/sup 2/ at 100 A/cm/sup 2/ and an efficiency of 4.4 cd/A.

A variety of polyethers were synthesized by a tandem approach incorporating ring-closing metathesis (RCM) followed by ring-opening metathesis polymerization (ROMP) using RuCl_2(=CHPh)(PCy_3)_2 (1) as an initiator. Unsaturated crown ether monomers, including a 12-crown-4 analogue (3), a benzocrown ether (8), and a benzocrown ether with a pendent phenylalanine methyl ester (9), were synthesized in good yields using a lithium ion as a template and 1 as a catalyst for RCM. Saponification of 9 afforded the benzocrown phenylalanine carboxylic acid monomer 10. The ROMP of 3, 8, and 9 with 1 as an initiator yielded the homopolymers 11, 12e, and 13e, respectively. The relative concentrations of 3 to 1 were varied to produce 11 with a wide range of molecular weights (M_n from 10 900 to 206 300). Hydrogenation of 11 proceeded quantitatively to yield a saturated polyether. Monomers 8 and 9 were copolymerized with 3 to generate polymers 12a−d and 13a−d, respectively. The copolymer composition corresponded to the feed ratio of the monomers. Crown ether 10 was copolymerized with 3 at a low feed ratio to form the corresponding polyether with pendent amino acids.

A stabilization of the liquid-crystalline mesophase and thus an enlarged temperature range of the mesogenic phase is achieved by adding perfluorotriphenylene to a chiral liquid-crystalline triphenylene. This mesophase is based on 1:1 perfluoroarene-arene interactions (see picture). In a polymer with triphenylenes as mesogens in the side chains, the addition of perfluorotriphenylene led to crystallization.