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Technology transfer is not only about the transfer of technology, but also about the transfer of knowledge, as evidenced by definitions of KM within the biopharma industry and beyond. However, knowledge transfer is often not well structured and its effectiveness – in particular for tacit knowledge (i.e., know how) – is an opportunity for improvement which can lead to many benefits. This article profiles recent research into the topic of improving knowledge transfer during technology transfer and presents several recently developed frameworks for improving such. The article furthermore explains how the frameworks can be co-deployed in support of robust knowledge transfer, supported by an illustrative case study.

The embryonic extracellular matrix (ECM) undergoes transition to mature ECM as development progresses, yet specific transition mechanisms ensuring ECM proteostasis and their regulatory impact are poorly defined. Fibrillin microfibrils are macromolecular ECM complexes serving structural and regulatory roles. In mice, Fbn1 and Fbn2, encoding major microfibrillar components, are strongly expressed during embryogenesis, but fibrillin-1 is the major component observed in adult tissue microfibrils. Here, analysis of mouse Adamts6 and Adamts10 mutant embryos, lacking these homologous secreted metalloproteases individually and in combination, along with in vitro analysis of microfibrils, measurement of ADAMTS6-fibrillin affinities and N-terminomics identification of ADAMTS6-cleaved sites, demonstrates a transcriptionally adapted system for fibrillin-2 proteolysis that contributes to postnatal fibrillin-1 dominance. The lack of ADAMTS6, alone and in combination with ADAMTS10 led to excess fibrillin-2 in perichondrium, with impaired skeletal development resulting from a drastic reduction of aggrecan, cartilage link protein and impaired BMP, but not TGFβ signaling in cartilage. Although ADAMTS6 cleaves fibrillin-1 and fibrillin-2 as well as fibronectin, which provides the initial scaffold for microfibril assembly, primacy of the protease-substrate relationship between ADAMTS6 and fibrillin-2 was unequivocally established by reversal of these defects in Adamts6-/- embryos by genetic reduction of Fbn2, but not Fbn1.

The multitalented therapeutic agent that is used to relieve a variety of ailments, acetylsalicylic acid (Aspirin® ) is facing new competition. The goal is to use tailor-made inhibitors of cyclooxygenase-2 to selectively reduce pain while minimizing side effects. Do these new drugs represent a new generation of nonsteroidal pain relievers?

The three dimensional growth of GaN structures as a basis for the fabrication of 3D GaN core-shell LEDs has attracted substantial attention in the past years. GaN nanorods or microrods with high aspect ratios can be grown by selective area epitaxy on a GaN buffer through a SiOx mask. It has been found earlier that silane substantially initiates vertical growth, with the exact underlying mechanisms being still unclear. Here, the influence of silane on the 3D GaN column growth was investigated by performing detailed growth experiments in combination with a thorough surface analysis in order to get insight into these mechanisms. The vertical growth rate is significantly enhanced by high silane fluxes, whereas the saturation of growth rate with the time is reduced. Thus, homogenous GaN columns with an aspect ratio of more than 35 could be achieved. A thin Si-rich layer on the non-polar m-plane facets of the columns has been detected using a combination of transmission electron microscopy, energy dispersive X-ray spectroscopy and Auger electron spectroscopy. This layer is suggested to be the reason for the increase in growth rate, modifying the effective collection range of the species along the sidewalls, and preventing the lateral growth.

Columnar structures of III–V semiconductors recently attract considerable attention because of their potential applications in novel optoelectronic and electronic devices. In the present study, the mechanisms for the growth of catalyst-free self-organized GaN columns on sapphire substrate by metal organic vapor phase epitaxy have been thoroughly investigated. The growth behaviours are strongly affected by the choice of carrier gas. If pure nitrogen is used, Ga droplets are able to accumulate on the top of columns during growth, and they are converted into a high quality GaN layer during the cool down phase due to nitridation. Hydrogen as the carrier gas can improve the optical quality of the overall GaN columns substantially, and in addition increase the vertical growth rate. In this case, no indication of Ga droplets could be detected. Furthermore, silane doping during the growth promotes the vertical growth in both cases either pure nitrogen or pure hydrogen as the carrier gas.

Vertically aligned GaN nanorods have recently obtained substantial interest as a new approach to solid state lighting. In comparison to conventional planar LEDs, 3D NanoLEDs are expected to offer substantial advantageous: very low defect density, quasi free-standing, no strain due to mismatch of thermal expansion coefficients, no substrate bending even when grown on large area silicon. Core-shell strategies are another very interesting aspect. The active LED surface per wafer could be increased by more than one order of magnitude. However, most of these advantages have not yet been proven in real devices, which would include a quantitative comparison of light emission. Related to the 3D character, there are also technological risks. In the following we will discuss the main developments which have paved the way up to this point, including a detailed discussion of possible benefits and risks connected with the NanoLED approach (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Pulsed sputter deposition has been demonstrated to be a viable process for the growth of high quality GaN and InGaN/GaN LEDs. It enables the fabrication of nitride LEDs with a red emission wavelength at large areas. In this study, we explore details on the epitaxial sputter deposition of GaN with a particular emphasis on ion damage. By changing the argon to nitrogen ratio, we adjust the growth mode from island to layer growth. TEM revealed speckles in the epitaxial GaN, which could be identified as isolated basal stacking faults, acting as non-radiative recombination centers. Using Monte Carlo methods, we modeled the energies of backscattered and sputtered atoms in order to get information on the ion damage mechanisms. Considering the collisions on the way from the target to the substrate, we found energetic nitrogen to induce the speckles. A shielding mechanism based on metallic gallium has been identified, leading to the strongly increased luminescence quality in comparison to the non-shielded material.

The present study relates to the applicability of silicon nanoparticles as basic component in printing inks for the fabrication of printable electronic devices. It is systematically investigated, how the surface functionalization of silicon nanoparticles with 1-alkenes affects the electrical properties of thin films made of them. Therefore, films of as-prepared silicon nanoparticles with a size of 42 nm as well as freshly etched ones, both terminated with hydrogen, are compared with films of silicon nanoparticles functionalized with n-octene, n-dodecene, allylmercaptan, and allylamine, respectively. It is found, that the activation energy of the electron transport through the films is in the range of 0.5 eV and scales with the polarity of the functionalization.

The functionalization of silicon nanoparticles by thermally induced hydrosilylation in a one-pot process is reported. In contrast to the commonly applied thermally induced hydrosilylation, the process described here is carried out in the presence of hydrofluoric acid as a second phase and therefore proceeds at a lower conversion temperature. The surface functionalization of silicon nanoparticles was analyzed by IR, 13C CPMAS NMR, EELS, and TGA techniques. The applied procedure resulted in functionalized silicon nanoparticles with good chemical and thermal stability.

Based on Fourier transform infrared (FTIR) spectroscopy and bulk micro-defect investigations, in relation to earlier results of other groups, we suggest the following model for oxide precipitate nucleation in N-doped silicon. Around 600 °C a nucleation maximum exists where oxide precipitates are formed via oxygen attachment to both NOO and NNO complexes. These complexes are formed by the reaction of NN with interstitial oxygen. Vacancy supersaturation enhances this type of precipitate nucleation. A second nucleation maximum exists around 900 °C. This is assumed to be due to a vacancy assisted oxynitride SiO x N y based nucleation process. The higher density of the oxynitride phase compared to silicon oxide and a higher residual vacancy concentration would explain the observed shift of the maximum nucleation rate to higher temperatures around 900 °C.

The thermodynamic data of the system SnO2/SnO/Sn in the absence and presence of CH4 and C are calculated as a function of temperature. The direct dissociation of SnOx without any reducing substances needs temperatures T>2000 K at 1 bar. In the presence of CH4 or C, SnOx can be reduced at T

The two-phase hydroformylation of lower olefins (Ruhrchemie–Rhone/Poulenc process) is a well known example of a multiphase fluid–fluid reaction (two liquid phases and a gas phase). Typically, reactions of this type are performed in stirred tank reactors. Investigation of the reaction in a packed tubular reactor revealed, that under very unconventional operation conditions space-time yields of 1-3 t m −3 h −1 are accessible. Compared to the conventional process, this is an increase by a factor of 10. This very surprising effect was clarified by simultaneous modelling of mass transfer and chemical reaction. Numerical simulations show that the effects are not due to a simple increase in mass transfer area. Alternative explanations are discussed. Further investigations in a mini pilot plant reveal a very simple yet highly efficient process design. Moreover, and in contrast to the conventional process higher olefins up to 1-octene can be converted to the respective aldehydes at reasonable space-time yields and with high selectivity. Successful application of the process principles to other fluid–fluid reactions suggests, that we have possibly found a more general concept for multiphase reactions.

Sustainable chemistry aims at an improved efficiency of using natural resources which are used to meet human needs for chemical products. Chemists in science and industry, have become aware of the importance to design environmentally benign chemicals. One aspect is the biological persistence and the present paper reviews work in this field focussing on the degradation of xenobiotics in the environment. Different structural reasons for chemical and biological persistence are described and strategies to use single bacterial isolates or microbial communities for the elimination of xenobiotic pollutants in the environment are summarized. Perspectives and limitations to evolve and use this catabolic potential are critically discussed with respect to the complexity of mixtures of xenobiotics often found in practice. An interdisciplinary approach for the prospective design of environmentally benign substances is presented and examples for new commodity chemicals that better fit the naturally existing catabolic potential are included.

Die Hartung von 4-Phenyl-4-(2,3-epoxypropoxy)benzoat (I) mit den isomeren Aminophenylaminobenzoaten II bis V fuhrt zu unterschiedlich geordneten Epoxidnetzwerken. Die Bildung verschiedener Intemediate wahrend der Hartungsreaktion wurde anhand von Modellverbindungen studiert. Aus der Reaktion der monoamino-substituierten Phenylbenzoate VI bis IX mit Epoxid wurden die Reaktionskostanten fur die Addition an das primare und das sekundare Wasserstoffatom der Aminogruppen bestimmt. Die kinetischen Daten lassen sich fur eine schrittweise Simulation des Hartungsverlaufs verwenden. Es wurden Argumente dafur gefunden, das sich bei Verwendung der Amine mit 4-Aminobenzoat-Strukturen gut geordnete, schnell vernetzende Intermediate bilden. 4-Phenyl-4-(2,3-expoxypropyl)benzoate (I) can be cured to thermoset networks with a different degree of order by using isomeric aminophenyl aminobenzoates II to V as curing agents. The formation of intermediates during the curing reaction was studied by means of model compounds. From the reaction of the monoamino-substituted phenylbenzoates VI to IX the reactivities for the primary and the secondary aminoprotons towards epoxide was determined. The kinetic data were used for a stepwise simulation of the curing reaction. Arguments were found that in case of diamines with 4-aminobenzoate structure well ordered intermediates are formed, which crosslink in an early stage of the reaction.

The multitalented therapeutic agent that is used to relieve a variety of ailments, acetylsalicylic acid (Aspirin® ) is facing new competition. The goal is to use tailor-made inhibitors of cyclooxygenase-2 to selectively reduce pain while minimizing side effects. Do these new drugs represent a new generation of nonsteroidal pain relievers?

The Langmuir-Blodgett film formation and the nonlinear optical properties of three polysiloxane polymer materials have been investigated. All three compounds could be built-up as Z-type layers on a variety of substrates. Experiments on the linear electrooptic (Pockels') effect revealed a second-order nonlinear susceptibility χ (2) (− ω ; ω , 0) of 10.6 pmV −1 for one of the materials; the order of magnitude of this result was confirmed using second-harmonic generation. For multilayer films the second-harmonic intensity was found to increase with the thickness of the LB structure. However, a linear dependence upon film thickness was evident, rather than the expected quadratic variation.

Symmetrical carbonates were formed when the corresponding carbonochloridates containing electron-withdrawing groups were converted with tertiary amines in dry solvents at room temperature. 5-Norbornene-2,3-dicarboximido carbonochloridate (1) and bis(5-norbornene-2,3-dicarboximido) carbonate (5) were used for acylation of OH groups in polymers in the presence of tertiary amines under anhydrous conditions. The influence of the amounts of 1 and 5, the kind and amount of amines, the organic solvent, the reaction time and temperature on the yield of the active carbonate 7 was investigated using bead cellulose as polymer. The reaction based on the catalysis by strongly nucleophilic amines such as 4-dimethylaminopyridine (DMAP) was optimized for preparation of acylated polymers. The formation of cross-linking and cyclic carbonates 9 and 10, respectively, was observed as a side reaction. It was shown that carbonates 9 and 10 can also be obtained as the main products of acylation. The preparation of 9 was also carried out by treating 7 with an excess of DMAP. Examples are presented for the transesterification of 7 with compounds containing OH groups. The acylated polymers were characterized by a specific titration method, UV/VIS and IR spectroscopy. The mechanism of the DMAP-catalyzed acylation of polymers is discussed.

Novel ternary pnictides Na2M3Y4 (M = Sr, Eu; Y = P, As) have been prepared from binary pnictides (Na3Y and MY) and the element Y. The compounds are isotypic to Gd5Si4 (Pearson code oP 36) as revealed by single crystal X-ray diffraction (Pnma (No. 62); Na2Sr3P4: a = 735.2(2) pm, b = 1525.0(3) pm, c = 797.9(2) pm; Na2Eu3P4: a = 729.8(2) pm, b = 1504.3(3) pm, c = 788.1(1) pm; Na2Eu3As4: a = 745.9(2) pm, b = 1542.1(4) pm, c = 813.2(2) pm). These pnictides are Zintl phases containing M2+ and Na+ cations and Y4−2 dumbbells with d (PP) = 228.5 and 226.8 pm and d ( AspAs ) = 249.1 pm . The study of magnetic susceptibility and specific heat shows that Na2Eu3As4 undergoes an antiferromagnetic phase transition at 5.38 K and a predominately ferromagnetic transition at 15.2 K.

We investigate photonic crystal waveguides that are formed by holes of reduced diameter within a hexagonal lattice of cylindrical airholes in thin freestanding silicon slabs. The waveguides operate in both an even-symmetry bandgap and a partial gap of odd-symmetry modes that form a complete two-dimensional bandgap under the light line. The operating frequency is tuned by the small-hole diameter to fit within the range of both bandgaps and to match a free-space wavelength of 1550 nm. Their narrow bandwidth and low group velocity of light propagation renders the waveguides useful as filters or sensing elements. Because of the strong dependence of the waveguide mode characteristics on structural changes, the highest-precision lithographic fabrication techniques must be applied.

Polypropylene homopolymers made by three different stereorigid metallocene catalysts (two isospecific, one syndiospecific) are compared with each other and with commercial samples made by a heterogeneous catalyst. The comparison includes mechanical properties, DSC-, 13-C NMR- and WAXS-data. The correlation between microscopic data and macroscopic properties is discussed. A novel particle-forming process in propylene bulk polymerization with stereorigid metallocene catalysts is demonstrated and discussed.

Die Titelverbindungen wurden aus den Elementen dargestellt. K4BeP2 und K4BeAs2 sind isotyp und kristallisieren trigonal-rhomboedrisch in der Raumgruppe R3m (Nr. 166) mit Z = 3. Die Teilstruktur der Kaliumatome entspricht einer dichtesten Packung von Rotationsellipsoiden, welche ein gestrecktes K14-Polyeder (Kombination von Rhomboeder und hexagonalem Prisma) einhullen. Die Polyeder sind durch lineare [BeX2]4−-Anionen aufgefullt, Analoga des BeCl2-Molekuls. Die Bindungslangen sind d(BeP) = 198,2 qm und d(BeAs) = 206,0 pm. IR-Spektren belegen die Existenz von [SbBeSb]4−-Anionen auch in K4BeSb2, welches im hexagonalen System mit Z = 2 kristallisiert. Die Schwingungsspektren der Verbindungen wurden gemessen. Die Zuordnung der beobachteten Frequenzen basiert auf der D∞h-Symmetrie einer isolierten [XBeX]4−-Einheit. K4BeP2, K4BeAs2, and K4BeSb2 Compounds with Linear [BeX2]4− Anions (X = P, As, Sb) The title compounds are synthesized from the elements. K4BeP2 and K4BeAs2 are isostructural and crystallize trigonal rhombohedrally in the space group R3m (No. 166) with Z = 3. The partial structure of the potassium atoms corresponds to a closest packing of rotational ellipsoides, which envelope an elongated K14-polyhedron (combination of rhombohedron and hexagonal prism). The polyhedrons are filled with linear [BeX2]4− anions, which are the analoga to BeCl2 molecules. The bond lengths are: d(BeP) = 198.2 pm and d(BeAs) = 206.0 pm. IR spectra confirm the presence of [SbBeSb]4− anionic groups in K4BeSb2, which crystallizes in the hexagonal system with Z = 2. The vibrational spectra of the compounds are measured. The assignment of the observed frequencies is based on the D∞h symmetry of an isolated [XBeX]4− unit.

The introduction of mesogenic groups in main- and sidechains of epoxy thermosets results in an ordered multiphase network with cellular structure, if gelation occurs below the maximal cure temperature Tmax. Tmax is individual for a given combination of monomers. The multiphase network consists of relatively soft anisotropic cell nuclei and hard isotropic cell walls. If gelation occurs above Tmax single phase networks are obtained. The size of the cell nuclei strongly depends on the used monomers and varies up to two orders of magnitude. The multiphase structure was found to have no impact on the tensile elastic modulus.

Publisher Summary Fiber-based materials in technical applications are an increasing worldwide market and cover a wide area. Interesting applications for fibers with nanoscaled dimensions or nanostructured surfaces are in mobility, gas and liquid filtration, fiber reinforced materials, and protection and professional protective clothing. Nanotechnology is considered to increase the number, variety, and effectivity of physical properties of existing products and, therefore, act as an innovative base for new products. There are many ways to implement nano-scale controlled properties into textiles. One is to give the fiber itself a nano-scale by fiber spinning. With novel fiber spinning technologies, it is possible to spin fibers with diameters between 20 and 500 nm; 10–500 times thinner than fibers spinnable by traditional fiber spinning techniques. The aim is to make the production of fibers with diameters below 100 nm highly productive and state-of-the-art. In order to achieve effects from nanostructures in the fiber bulk, either nanoparticle-filled polymer melts or nanophase-separating polymeric systems can be spun. Nanofillers such as clay have been known for decades, but the processing of those filled polymeric melts is challenging because agglomeration has to be avoided and the influence of nanoparticles on rheological properties can be great.

Chiral bridged bisindenyl zirconoeenes with special substitution patterns on the aromatic rings are potentially commercial catalysts for the production of isotactic polypropylenes. The performance characteristics of these systems are different, the variations being induced by size and position of the substituents. The novel catalysts will be used for the production of new iPP grades with enhanced properties or unprecedented property combinations. Typical features of metailocene iPP polymers are higher stiffness, higher transparency, and a lower level of extractables than conventional products. The most recent new designs of metailocene PP catalysts are discussed. These include asymmetric systems and metallocenes inducing two-step-polymerization mechanisms.

The structure of pyramidal inversion domain boundaries in GaN:Mg was investigated by aberration corrected transmission electron microscopy. The analysis shows the upper (0001) boundary to consist of a single Mg layer inserted between polarity inverted GaN layers in an abcab stacking. The Mg bound in these defects is at least one order of magnitude lower than the chemical Mg concentration. Temperature dependent Hall effect measurements show that up to 27% of the Mg acceptors is electrically compensated.

Several yeast strains were assayed for occurence of nitrate reductase after growth in a defined medium with nitrate as the sole nitrogen source, Candida boidinii DSM 70026, showing the highest specific activity, was further investigated. The procedures for yeast fermentation and nitrate reductase purfication are described in detail. Nitrate reductase from this yeast was characterized as NAD(P)H: nitrate oxidoreductase (E.C.1.6.6.2). The enzyme activity with NADH (NADPH) was highest at pH 7.0 (7.1) and 30° C (25° C). The values of Km determinations with NADH/NADPH were both 4 × 10−4 mol/l; values for the substrate inhibition constant (Ki) were 6 × 10−4 mol/l. The molecular mass of the native enzyme was estimated by gel permeation chromatography to be approximately 350 kDa.

To obtain highly isotactic polypropylene chiral metallocenes have to be used. In this work it is shown that chirality is a necessary but not sufficient condition for high isospecifity. Variation of metallocene structure retaining chirality can lead to strongly reduced isospecifity. Breakdown of stereospecifity by slight structural variation can also be demonstrated with syndiospecific metallocene catalysts.

Description d'une approche alternative pour augmenter la stabilite de couche multimoleculaire: incorporation d'un groupe chromophore dans la chaine laterale d'un polysiloxane

Spiro-β-lactams from [2+2]-Cycloaddition of Ketenes to Iminolactones Iminolactones (‘Isoimides’) derived from maleic anhydride and amines are shown to react with various ketenes in a [2+2]-cycloaddition mode. Either preformed ketenes or the combination acid chloride/tertiary amine can be used as reagent. The reaction products have been assigned the spiro-β-lactam structure. Unsubstituted ketene is inert under the reaction conditions. It is possible to synthesize the spiro-β-lactams in a one-pot procedure, starting from a mixture of maleic anhydride/amine and excess dialkylketene.

Chemistry of Spiro-β-lactams Reactions of the easily accessible spiro-β-lactams 1 are described. These comprise hydrogenation, hydrolyses and alcoholyses, reaction with hydrazine, and lead to new heterocyclic compounds. Some further transformations of the products are shown.

Als Zwischenprodukt der zum Dihydridokomplex RuH2(pp3) (1) fuhrenden Umsetzung von RuCl2(pp3) mit LiAlH4 in THF lies sich eine auserst labile polyhydridische Aluminatoverbindung der Zusammensetzung [Li3Ru2H3(AlH4)4(pp3)2(OC4H8)2]x (2) isolieren [pp3 = P(CH2CH2CH2PMe2)3]. 1 reagierte mit HBF4 unter Bildung von [RuH(pp3)]BF4 (3); das Trihydrido-Derivat [RuH3(pp3)]BF4 wurde nicht erhalten. Die Einwirkung von Kohlendioxid auf 1 fuhrte zum Formato-Komplex RuH[OC(O)H](pp3) (4). Bei der Photolyse von 1 in C6D6 entstand als metallorganisches Produkt ausschlieslich RuD(C6D5)(pp3), was fur die photochemische Bildung von RuH(C6H5)(pp3) (5) aus 1 und Benzol den Schritt einer oxidativen CH-Addition an das koordinativ ungesattigte Fragment Ru(pp3) nahelegt. Die Molekulstruktur von 5 wurde rontgenographisch ermittelt. Oligophosphane Ligands, XXVII. — RuH2[P(CH2CH2/CH2PMe2)3]: Formation, Protonation, CO2 Insertion, and Oxidative Addition of Benzene An extremely labile polyhydric aluminato species of composition[Li 3Ru2H3(AlH4)4(pp3)2(OC4H8)2]x (2) was isolated as an intermediate of the reaction between RuCl2(pp3) and LiAlH4 in THF, which leads to RuH2(pp3) (1) as the final product [pp3 = P(CH2CH2CH2PMe2)3]. 1 reacted with HBF4 to produce [RuH(pp3)]BF4 (3); the conversion of 1 into the trihydrido derivative [RuH3(pp3)]BF4 failed. Exposure of 1 to CO2 yielded the formato complex RuH[OC(O)H](pp3) (4). Photolysis of 1 in C6D6 gave RuD(C6D5)(pp3) as the exclusive organometallic product, which strongly suggests that the photochemical formation of RuH(C6H5)(pp3) (5) from 1 and C6H6 proceeds by oxidative addition of benzene CH bonds to the coordinatively unsaturated fragment Ru(pp3). The molecular structure of 5 was determined by X-ray diffraction.

Starting from ethyl 2-cyclohexen-1-carboxylate (3) the total synthesis of the perhydrohistrionicotoxin intermediate 23 was achieved in 25% overall-yield. The two key steps involve a positionally specific addition of HOBr to the oxime-olefin 7 and the alkylation of bromooxime 17 with 1-lithio-1-butyne. The latter represents a novel method for stereospecific and position-specific introduction of a nucleophilic butyl equivalent in α-position to a ketonic carbonyl group.

We present a comparison of two methods for assessing the second-order non-linear optical properties of Langmuir-Blodgett films. The well-known study by second harmonic generation using a high powered laser is preferred if details of the film's tilt characteristics are required. However, we show that the more convenient, low power method for electro-optic response by surface plasmon spectroscopy gives an adequate screening method for the magnitude and sign of the second-order non-linearity from Langmuir-Blodgett layers of novel materials. We describe the synthesis, deposition and assessment by these techniques of two new stilbazolium amphiphiles. These amphiphiles are designed with their principal β tensor component in opposition to our previously studied hemicyanine and thus may facilitate the formation of non-linear Langmuir-Blodgett superlattices consisting of alternating dyes.

The complex (1) was obtained by reduction of FeCl2[P(CH2CH2CH2PMe2)3] with lithium dust in tetrahydrofuran at room temperature. Although an equilibrium of 1 with its iron(0) tautomer Fe[P(CH2CH2CH2PMe2)3] could not be detected by NMR spectroscopy, the coordinatively unsaturated 16e-fragment could be trapped by ligands favouring low oxidation states: trimethyl phosphite reacted with 1 to give Fe[P(OMe)3][P(CH2CH2CH2PMe2)3] (2), whereas carbon monoxide was observed to add to the metal(O) species to yield a mixture of Fe(CO)[P(CH2CH2CH2PMe2)3] (3) and -(CH2)3-PMe2 (4). 1 was completely unreactive towards dihydrogen and dinitrogen, not, however, towards carbon dioxide, which was found to insert into both the Fe-H and Fe-C bond producing (5). Methyl and benzyl iodide interacted with 1 to give the iodo derivative (6). The reaction of 1 with methanol lead to FeH2[P(CH2CH2CH2PMe2)3] (7).

together with a parameter krcl indicating the relative outersphere reactivity. The order for krel parallels the rates of dissolution of metal oxide films by these reagents and suggests that of these common reductants, only Cr(edta)2is more potent than V(pic),-. The self-exchange rate for V(pic)jo/of 3.1 X lo6 M-l s-l is 8 orders of magnitude larger than the value for V(H20)63+/2+.42 This may imply that the structural rearrangement associated with the electron-transfer process is

Versatile procedures for the preparation of the title compounds are described. Representatives of ketones (12 and 27), hydrocarbons (19 and 28), acids (13), esters (15. and 20), ethers (22) and nitriles (18) possess wide-range nematic phases, provided their terminal chains R2 and R3 contain at least three methylene units.

In order to make a decision between the quinone acetal equilibration/quinone acetal rearrangement and the so far discussed SET mechanism for the oxidative coupling of 2,6-xylenol to poly(oxy-2,6-dimethyl-1,4-phenylene) the polymerization was carried out in the presence of 5-(2,6-dimethylphenoxy)-2-methoxy-1,3-xylene (1) (the methylated dimer) or α-methyl-ω-phenoxypoly(oxy-1,4-phenylene) [O-methylated poly(phenylene ether)] (2). GC and GPC studies indicated that neither 1 nor 2 are incorporated into the polymer. These observations exclude the SET-mechanism according to Scheme 4.

The UV/azo-bis(isobutyronitrile)-initiated addition of several secondary phosphines R2PH (R=Ph; Me, i-Pr, t-Bu, Cy) to the carbon-carbon double bonds of R'P(CH2CH=CH2)2 (R'=Me, t-Bu; Ph; CH2CH=CH2)2 P(CH2CH2CH=CH2)3, N(CH2CH=CH2)3, and As(CH2CH=CH2)3 was investigated with the aim of exploring the reaction scope. i-Pr2PH, t-Bu2PH, and Cy2 PH failed to add, or to completely add, to the allylphosphines chosen. Similarly, the hoped-for tripod tetratertiary ligands E(CH2CH2CH2PMe2)3 (E=N, As) could not be made accessible by coupling Me2PH onto triallylamine and triallylarsine, respectively. On the positive side, the facultative tri- and tetradentates t-BuP(CH2CH2CH2PPh2)2 and P(CH2CH2CH2CH2PMe2)2 have been obtained in high yields by irradiating mixtures of t-BuP(CH2CH˭CH2)2 or P(CH2CH2CH˭CH2)3 and excess Me2PH in the presence of catalytic amounts of azo-bis(isobutyronitrile). The rhodium complex RhCl[t-BuP(CH2CH2CH2PPh2)2)2] derived from one of these ligands was characterized by X-ray diffraction. Die...