bluuebunny/crossref_metadata_2025 huggingface dataset:
Optical properties of structurally sorted single‐wall carbon nanotube ensembles
Authors: Crochet J. , Clemens M. , Hertel T.
Published: October 2007

Using density gradient ultracentrifugation and isopycnic fractionation we structurally sort traditionally prepared single‐wall carbon nanotube suspensions, and show that fractions with photoluminescence (PL) quantum yields of over 1% can be isolated. Moreover, we find that traditionally prepared suspensions appear to be composed of a significant fraction of small nanotube aggregates which reduce the quantum yield of the ensembles by a factor of 5 with respect to the most photoluminescent fractions. In order to better understand the nature of the nonradiative decay processes that lead to lower ensemble PL quantum yields, nanotube ropes of diameter enriched tubes are made and compared with the aforementioned ensemble measurements. Changes in the optical properties are discussed in terms of energy transfer to metallic tubes, carbonaceous particles, and smaller band gap tubes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carbon nanotubes in liquid crystals as versatile functional materials
Authors: Scalia Giusy , Lagerwall Jan P. F. , Schymura S. , Haluska M. , Giesselmann F. , Roth Siegmar
Published: October 2007

Liquid crystals can be easily aligned in desired directions by treated surfaces or by external fields. The least ordered liquid crystal phase, the nematic, exhibits orientational order that can be easily transferred onto carbon nanotubes dispersed in it. The alignment of the carbon nanotubes can be demonstrated by polarized Raman spectroscopy. Carbon nanotubes not only well integrate in the matrix but also, even at very low concentration, have a detectable effect on the liquid crystal properties that can be very attractive for display applications. The presence of big aggregates of carbon nanotubes, on the other hand, interfere strongly with the switching behaviour of the liquid crystal, as we can show following the local switching of liquid crystal molecules with Raman spectroscopy. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Random and localized resistive switching observation in Pt/NiO/Pt
Authors: Yun Jung‐Bin , Kim Sejin , Seo Sunae , Lee Myoung‐Jae , Kim Dong‐Chul , Ahn Seung‐Eon , Park Yongsoo , Kim Jiyoung , Shin Hyunjung
Published: October 2007

Resistive memory switching devices based on transition metal oxides are now emerging as a candidate for nonvolatile memories. To visualize nano‐sized (10 nm to 30 nm in diameter) conducting filamentary paths in the surface of NiO thin films during repetitive switching, current sensing–atomic force microscopy and ultra‐thin (<5 nm) Pt films as top electrodes were used. Some areas (or spots), which were assumed to be the beginning of the conducting filaments, appeared (formation) and disappeared (rupture) in a localized and random fashion during the switching and are thought to contribute to resistive memory switching. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical calculation of overlap and kinetic integrals in prolate spheroidal coordinates. II
Authors: Romanowski Zbigniew
Published: October 2007

The efficient algorithm calculating the overlap and the kinetic integrals for the numerical atomic orbitals is presented. On the basis of the prolate spheroidal coordinates, the overlap and the kinetic integral are reduced to the integral over the rectangular domain. The integration over the rectangular domain is performed by the adaptive integration scheme. The developed algorithm is applied to calculate the integrals for the pairs of hydrogen and gallium eigenfunctions. It is demonstrated that high accuracy can be obtained for small number of integrand evaluations what guarantees the efficiency of the presented algorithm. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Role of aromatic residues in stabilizing the secondary and tertiary structure of avian pancreatic polypeptide
Authors: Palermo Nicholas Y. , Csontos József , Murphy Richard F. , Lovas Sándor
Published: October 2007

Avian pancreatic polypeptide (aPP) is a 36 residue protein that exhibits a tertiary fold. Results of previous experimental and computational studies indicate that the structure of aPP is stabilized more by nonbonded interactions than by the hydrophobic effect. Aromatic residues are known to participate in a variety of long‐range nonbonded interactions, with both backbone atoms and the atoms of other side‐chains, which could be responsible, in part, for the stability of both the local secondary structure and the tertiary fold. The effect of these aromatic interactions on the stability of aPP was calculated using BHandHLYP/cc‐pVTZ. Aromatic residues were shown to participate in multiple hydrogen bonded and weakly polar interactions in the secondary structure. The energies of the weakly polar interactions are comparable with those of hydrogen bonds. Aromatic residues were also shown to participate in multiple weakly polar interactions across the tertiary fold, again with energies similar to those of hydrogen bonds. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Mass fingerprinting of toxic fractions from the venom of the Indian red scorpion,Mesobuthus tamulus: biotope‐specific variation in the expression of venom peptides
Authors: Newton Kirsti A. , Clench Malcolm R. , Deshmukh Ranjana , Jeyaseelan Kandiah , Strong Peter N.
Published: October 2007

The red scorpion,Mesobuthus tamulus, is found in two distinct biotopes within the Indian state of Maharastra—a tropical, sea‐level biotope and a semi‐arid biotope, up to 600 m. Scorpions from these two geographical areas show marked differences in toxicity. Using mass spectrometry, we have shown biotope‐specific variation in the expression of peptides from scorpions collected from these two distinct areas. Matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry (MALDI‐TOFMS) and reversed‐phase liquid chromatography/electrospray ionisation mass spectrometry (LC/ESI‐MS) were assessed as techniques for obtaining mass fingerprint data. On line LC/ESI‐MS was judged to be the method of choice and unique biotope‐specific mass fingerprints, with key diagnostic markers, were obtained. Copyright © 2007 John Wiley & Sons, Ltd.
Direct visualisation of peptide hormones in cultured pancreatic islet alpha‐ and beta‐cells by intact‐cell mass spectrometry
Authors: Buchanan Christina M. , Malik Arpita S. , Cooper Garth J. S.
Published: October 2007

The application of intact‐cell mass spectrometry (ICM) by matrix‐assisted laser desorption/ionisation time‐of‐flight (MALDI‐TOF) mass spectrometry to achieve direct protein‐profiling of bacterial species is now well established. However, this methodology has not to our knowledge been applied to the analysis of mammalian cells in routine culture. Here, we describe a novel application of ICM by which we have identified proteins in intact cells from two lines representative of pancreatic islet α‐ and β‐cells. Adherent αTC1 clone 9 and βTC6 F7 cells were harvested into phosphate‐buffered saline (PBS) using enzyme‐free dissociation buffer before 1 µL of cell suspension was spotted onto MALDI plates. Cells were overlaid with sinapinic acid then washed with pure water before application of a final coat of sinapinic acid. Data in the 2000–20 000 m/z range were acquired in linear mode on a Voyager DE‐Pro mass spectrometer. The proteins which ionised were composed in large part of peptide hormones (e.g. insulin and glucagon) known to be packaged into the secretory granules of the β‐ and α‐cells respectively. However, in addition to visualising the peptides expected to be associated with these cells, a mass consistent with oxyntomodulin was identified in the cultured α‐cells, a finding not previously reported to our knowledge. In summary, this paper describes, for the first time, a rapid and direct method useful for identifying secretory products in intact endocrine cells. Copyright © 2007 John Wiley & Sons, Ltd.
State feedback controller design of networked control systems with interval time‐varying delay and nonlinearity
Authors: Peng Chen , Tian Yu‐Chu , Tadé Moses O.
Published: October 2007

This paper proposes a method for robust state feedback controller design of networked control systems with interval time‐varying delay and nonlinearity. The key steps in the method are to construct an improved interval‐delay‐dependent Lyapunov functional and to introduce an extended Jessen's inequality. Neither free weighting nor model transformation is employed in the derivation of system stability criteria. It is shown that the maximum allowable bound on the nonlinearity could be computed through solving a constrained convex optimization problem; and the maximum allowable delay bound and the feedback gain of a memoryless controller could be derived by solving a set of linear matrix inequalities. Numerical examples are given to demonstrate the effectiveness of the proposed method. Copyright © 2007 John Wiley & Sons, Ltd.
Mimetic entry and bandwagon effect: the rise and decline of international equity joint venture in China
Authors: Xia Jun , Tan Justin , Tan David
Published: October 2007

The rise and decline of foreign entry strategies in transition economies is an important yet largely overlooked issue in the literature. This study is a step toward filling this gap by examining how mimetic entry within reference groups and the emergence of a competing strategy affect the bandwagon phenomenon of a dominant strategy in the context of China, where international equity joint ventures (EJVs) used to be a dominant entry strategy among foreign firms in the 1990s. Findings from a sample of 1,123 EJVs formed in China's non‐restricted industries from 1990 to 2003 show that the impact of home and host‐country industry effects are not symmetric between the EJV rise and decline periods. Cross‐border merger and acquisition (M&A) as a competing strategy has an important impact during the EJV decline period but not the rise period. The interactive effects between EJV and M&A strategies occur only in the host‐country industries. We discuss such results and offer suggestions for future research. Copyright © 2007 John Wiley & Sons, Ltd.
Elementary teachers' epistemological and ontological understanding of teaching for conceptual learning
Authors: Kang Nam‐Hwa
Published: October 2007

The purpose of this study was to examine the ways in which elementary teachers applied their understanding of conceptual learning and teaching to their instructional practices as they became knowledgeable about conceptual change pedagogy. Teachers' various ways to interpret and utilize students' prior ideas were analyzed in both epistemological and ontological dimensions of learning. A total of 14 in‐service elementary teachers conducted an 8‐week‐long inquiry into students' conceptual learning as a professional development course project. Major data sources included the teachers' reports on their students' prior ideas, lesson plans with justifications, student performance artifacts, video‐recorded teaching episodes, and final reports on their analyses of student learning. The findings demonstrated three epistemologically distinct ways the teachers interpreted and utilized students' prior ideas. These supported Kinchin's epistemological categories of perspectives on teaching including positivist, misconceptions, and systems views. On the basis of Chi's and Thagard's theories of conceptual change, the teachers' ontological understanding of conceptual learning was differentiated in two ways. Some teachers taught a unit to change the ontological nature of student ideas, whereas the others taught a unit within the same ontological categories of student ideas. The findings about teachers' various ways of utilizing students' prior ideas in their instructional practices suggested a number of topics to be addressed in science teacher education such as methods of utilizing students' cognitive resources, strategies for purposeful use of counter‐evidence, and understanding of ontological demands of learning. Future research questions were suggested. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 44: 1292–1317, 2007
Identification and characterization of a novel yeast ω3‐fatty acid desaturase acting on long‐chain n‐6 fatty acid substrates from Pichia pastoris
Authors: Zhang Xinxin , Li Mingchun , Wei Dongsheng , Xing Laijun
Published: October 2007

A cDNA sequence putatively encoding a ω3‐fatty acid desaturase gene was isolated from methylotrophic yeast Pichia pastoris GS115. The deduced amino acid sequence of this cloned cDNA showed high identity to known fungal ω3‐fatty acid desaturases. Functional identification of this gene heterologously in Saccharomyces cerevisiae strain INVScl indicated that the deduced amino acid sequence exhibited ω3‐fatty acid desaturase activity. The newly identified ω3‐fatty acid desaturase, named Pp‐FAD3, is novel because it showed broad n‐6 fatty acid substrate specificity by its ability to convert all the 18‐carbon and 20‐carbon n‐6 substrates examined to the corresponding n‐3 fatty acids, with an approximately equivalent high conversion rate. Pp‐FAD3 is the first known yeast ω3‐fatty acid desaturase to act on long‐chain n‐6 fatty acid substrates. Heterologous expression of the newly identified ω3 desaturase in different hosts will be an alternative method to increase the flow of n‐6 fatty acid intermediates into their n‐3 derivatives. Pp‐fad3 has been assigned GenBank Accession No. EF116884. Copyright © 2007 John Wiley & Sons, Ltd.
Genome‐wide analysis of coding DNA and amino acid variation in Saccharomyces cerevisiae
Authors: Tan Haidong , Wang Jinxia , Yang Fan , Zhao Zongbao K.
Published: October 2007

The possible causes of variation on amino acid composition in the yeast Saccharomyces cerevisiae were investigated genome‐wide. The results indicated that: (a) the base composition of coding DNA and amino acid composition was similar among all the chromosomes, which was in sharp contrast with the great varies of the composition of the individual's coding DNA and amino acid; (b) some amino acids (e.g. Cys and Trp) were not present in all the proteins; and (c) amino acid bias was associated with a base bias (in terms of A‐, G‐, C‐ and T‐rich codons). Based on the third rule and a proposed universal trend of amino acid gain and loss in protein evolution, the changing pattern of coding DNA was predicted to be T‐ and C‐accruing, whereas A and G were consistently reducing. All these results held the potential to reveal precisely how DNA ongoing change has a major effect on the composition of proteins. Copyright © 2007 John Wiley & Sons, Ltd.
The transcriptional inhibitor thiolutin blocks mRNA degradation in yeast
Authors: Pelechano Vicent , Pérez‐Ortín José E.
Published: October 2007

Thiolutin is commonly used as a general inhibitor of transcription in yeast. It has been used to calculate mRNA decay rates by stopping the transcription and then determining the relative abundance of individual mRNAs at different times after inhibition. We report here that thiolutin is also an inhibitor of mRNA degradation, and thus its use can lead to miscalculations of mRNA half‐lives. The inhibition of mRNA decay seems to affect the mRNA degradation pathway without impeding poly(A) shortening, given that the decay rate of total poly(A) amount is not reduced by thiolutin. Moreover, the thiolutin‐dependent inhibition of mRNA degradation has variable effects on different functional groups of genes, suggesting that they use various degradation pathways for their mRNAs. Copyright © 2007 John Wiley & Sons, Ltd.
Membrane topology and post‐translational modification of the Saccharomyces cerevisiae essential protein Rot1
Authors: Angeles Juanes M. , Carlos Igual J. , Carmen Bañó M.
Published: October 2007

ROT1 is an essential gene that has been related to cell wall biosynthesis, the actin cytoskeleton and protein folding. In order to help to understand its molecular function, we carried out a characterization of the Rot1 protein. It is primarily located at the endoplasmic reticulum–nuclear membrane facing the lumen. Rot1 migrates more slowly than expected, which might suggest post‐translational modification. Our results indicate that Rot1 is a protein that is neither GPI‐anchored nor O‐glycosylated. In contrast, it is N‐glycosylated. By a directed mutagenesis of several Asn residues, we identified that the protein is simultaneously glycosylated at N103, N107 and N139. Although the mutation of these three N sites is not lethal, cellular growth is impaired. Sequence analysis predicts a transmembrane domain at the C‐terminus. This fragment affects neither the targeting of the Rot1 protein to the ER nor its N‐glycosylation, although it is important for the anchoring of the protein to the membrane and for its functionality. The existence of a signal sequence at the N‐terminus has been suggested. However, deletion of this fragment impedes neither translocation to the ER nor N‐glycosylation, but it is required for cell viability. Finally, we found that Rot1 is translocated to the ER by an SRP‐independent post‐translational mechanism which depends on Sec62. Copyright © 2007 John Wiley & Sons, Ltd.
Expression of glycerol 3‐phosphate dehydrogenase gene (CvGPD1) in salt‐tolerant yeast Candida versatilis is stimulated by high concentrations of NaCl
Authors: Watanabe Yasuo , Nagayama Kisako , Tamai Youichi
Published: October 2007

We cloned the glycerol 3‐phosphate dehydrogenase (GPDH) gene (CvGPD1) from salt‐tolerant yeast Candida versatilis. When CvGPD1 was expressed in glycerol synthesis‐deficient Saccharomyces cerevisiae cells, the salt tolerance of the recombinant strain was enhanced, and NADP+‐dependent GPDH (EC 1.1.1.94), Cvgpd1p synthesis and recovery of glycerol synthesis were confirmed. The transcription of CvGPD1 in C. versatilis cells was stimulated by high concentrations of NaCl. The relationship between expression of CvGPD1 and growth of C. versatilis cells in the mash of Japanese seasonings (miso‐ and shoyu‐moromi) is also discussed. The Accession No. for the sequenced DNA fragment is AB296385. Copyright © 2007 John Wiley & Sons, Ltd.
Reaktionen von MeInCl2 mit Lithiumalkoholaten
Authors: Chamazi Navabeh Nami , Heravi Majid M. , Neumüller Bernhard
Published: October 2007

Reactions of MeInCl2 with Lithium Alcoholates

MeInCl2 was treated with two equivalents of LiOR (R = iPr, tBu) in boiling toluene to give the In‐O cage compounds [(InMe)4(InCl)3(Cl)5(OiPr)5(O)2] (1) and [Li(InMe)5(InCl)(Cl)2(OtBu)8(O)] (2). 1 and 2 were characterized by NMR and IR techniques as well as by X‐ray structure determinations. According to them 1 can be divided formally into the two complex fragments [(InMe)(MeInCl)(InCl)(OiPr)3(O)] and [(InMe)(MeInCl)(InCl2)(OiPr)2(O)] which coordinate one unit of InCl3. In 2 the complex fragments [Li(InMe)2(OtBu)4] and [(InMe)(MeInCl)2(InCl)(OtBu)4(O)] coordinate a Cl– ion.
Synthesis, Crystal Structures and Properties of the Trimetaphosphimates Na2M(PO2NH)3 · 2H2O with M = K, Tl
Authors: Sedlmaier Stefan J. , Johrendt Dirk , Oeckler Oliver , Schnick Wolfgang
Published: October 2007

The double salt disodium thallium(I) tri‐μ‐imidocyclotriphosphate dihydrate, Na2Tl(PO2NH)3 · 2H2O, was obtained by evaporation of combined, equimolar, aqueous solutions of Na3(PO2NH)3 · 4H2O and TlOOCCH3. The structure determination of the pseudo‐merohedrally twinned crystals of Na2Tl(PO2NH)3 · 2H2O was performed by single‐crystal X‐ray methods ($P{\bar 1}$, no. 2, a = 799.1(2), b = 799.3(2), c = 864.6(2) pm, α = 76.83(3)°, β = 83.81(3)°, γ = 77.57(3)°, Z = 2). In the crystal structure the trimetaphosphimate ring shows a chair conformation and two cyclic anions are connected to each other by six N‐H···O hydrogen bonds. The [(PO2NH)3]3− pairs are interconnected in a three‐dimensional network building strands along [1–10] by coordination to the sodium ions, with several coordinating bonds to the thallium ions and further hydrogen bonds. According to an ELF‐calculation, there is no stereochemical influence of the 6s2‐electron pair at the thallium(I) ion in Na2Tl(PO2NH)3 · 2H2O. This finding is corroborated by a comparison with the analogous potassium compound, Na2K(PO2NH)3 · 2H2O, which was found to be isotypic to Na2Tl(PO2NH)3 · 2H2O.
Synthesis, Structure and Dynamics of a C2‐symmetrical Bis(oxazolinylmethylene)pyrrolinato‐Zinc Complex
Authors: Capacchione Carmine , Wadepohl Hubert , Gade Lutz H.
Published: October 2007

Reaction of 2,5‐bis(cyanomethyl)pyrrole with L‐valinol in presence of zinc trifluoromethansulfonate and subsequent work‐up with aqueous NaCl gave the corresponding zinc complex 2, in which the double bonds of the pyrrole ring isomerize to give rise to a conjugated chromophore. Its molecular structure displays tetrahedral distortion from planarity, as was established by a single crystal structure analysis. The non‐planarity of 2 gives rise to a dynamic behaviour in solution with the chlorido‐ligand swinging through the plane spanned by the three N‐donor functions.
Centered Indium Cubes as Structural Motifs in SrRh2In8 and SrIrIn4
Authors: Muts Ihor R. , Zaremba Vasyl I. , Pöttgen Rainer
Published: October 2007

The indium‐rich intermetallic compounds SrRh2In8 and SrIrIn4 were synthesised from the elements in sealed tantalum ampoules in a high‐frequency furnace. Both samples were investigated by X‐ray powder and single crystal diffraction: CaCo2Al8 type, Pbam, a = 1617.0(3), b = 1387.4(3), c = 438.26(9) pm, wR2 = 0.0495, 1971 F2 values, 70 variables for SrRh2In8 and LaCoAl4 type, Pmma, a = 867.8(2), b = 432.33(9), c = 765.4(2) pm, wR2 = 0.0516, 692 F2 values, 24 variables for SrIrIn4. In both structures, the indium atoms build up two‐dimensional networks of distorted triangles, squares, and pentagons in an AA stacking sequence. The resulting trigonal and square prismatic voids are filled by the transition metal and indium atoms, respectively. In SrIrIn4 the pentagonal prisms are occupied by strontium, while the latter are alternatingly occupied by strontium and indium in SrRh2In8. Together the transition metal and indium atoms build up complex three‐dimensional [IrIn4] (261–288 pm Ir–In and 310–335 pm In–In) and [Rh2In8] (261–292 pm Rh–In and 290–348 pm In–In) networks in which the strontium atoms are located in distorted pentagonal tubes.
Pt4S4 Clusters with Functionalized Thiosemicarbazones derived from 5‐Acetylbarbituric Acid
Authors: Bermejo Elena , Castiñeiras Alfonso , García‐Santos Isabel , Gómez‐Rodriguez Lourdes , Sevillano Paloma
Published: October 2007

Reaction of K2[PtCl4] with thiosemicarbazones derived from 5‐acetylbarbituric acid led to the isolation of the tetranuclear species [Pt(AcbM)]4 · 2/2DMSO · 2DMSO · 5H2O (1) and [Pt(AcbE)]4 · 4DMSO · 2H2O (2) (H2AcbM = 5‐acetylbarbituric‐4N‐methyl thiosemicarbazone and H2AcbE = 5‐acetylbarbituric‐4N‐ethyl thiosemicarbazone). Both of these compounds feature a Pt4S4 cluster in which some of the Pt–Pt distances suggest the existence of weak metal‐metal interactions. Crystals of these tetranuclear species are stabilized by intermolecular π‐π stacking interactions. The two compounds have almost equivalent molecular structures, differing only in the orientation of the substituent on the amine nitrogen atom of the thiosemicarbazone. The two tetranuclear complexes contain the thiosemicarbazone bonded as a terdentate ligand to the platinum atom through the thiolate sulfur atom, the azomethine nitrogen atom and the alcoholate oxygen atom of the 5‐acetylbarbiturate function.
Synthese und Charakterisierung neuer intramolekular phosphorstabilisierter Aluminium‐, Gallium‐ und Indiumorganyle
Authors: Schumann Herbert , Girgsdies Frank , Heymer Bernd , Kaufmann Jens , Marschall Christian , Wassermann Wilfried
Published: October 2007

Synthesis and Characterization of New Intramolecularly Phosphorus stabilized Aluminium, Gallium, and Indium Organyls

The intramolecularly phosphorus stabilized element‐13 organyls Me2M(CH2)3P(t‐Bu)2 (M = Al (1), Ga (2), In (3)) and Cl2M(CH2)3P(t‐Bu)2 (M = Al (5), Ga (6)) are formed by reacting Me2MCl and MCl3 with t‐Bu2P(CH2)3MgCl and t‐Bu2P(CH2)3Li (4), respectively. The reaction of Et2PCH2C6H4Br‐2 (7) with BuLi and Me2InCl produces Me2InC6H4CH2PEt2‐2 (8). [Me2InCH2PMe2]2 (9) results from the reaction of Me2PCH2Li with Me2InCl. The successive addition of BuLi, Cl(CH2)3Br, and Me2AlCl to t‐BuPH2 does not lead to the expected Me2Al(CH2)3PH(t‐Bu) (10), but affords [{cyclo‐P(t‐Bu)(CH2)3}CO2](AlMe2Cl)2 (12) formed during work‐up in the presence of CO2. The new compounds were characterized by elemental analyses, 1H, 13C, and 31P NMR spectroscopy, as well as mass spectrometry. Additionally, the structures of 2 and 12 were determined by single crystal X‐ray diffraction.
Zur Bildung einer Zinn‐Zinn‐Bindung in Bis(hexamethyldisilazyl)‐Zinn(II) unter C‐H Bindungsbruch
Authors: Veith Michael , Gasthauer Matthias , Zimmer Michael , Huch Volker
Published: October 2007

Formation of a Tin‐Tin‐Bond from Bis(hexamethyldisilazyl)‐Tin(II) under Fission of a C‐H Bond

Bis(hexamethyldisilazyl)tin(II) in excess reacts with the molecular alumosiloxane (Ph2SiO)8(AlO(OH))4 to yield the well known tin(II) derivative (Ph2SiO)8(AlO2)4Sn2 and the novel bicyclic [(Me3Si)2N]Sn[N(SiMe3)SiMe2CH2]2Sn[N(SiMe3)2] containing a tin‐tin bond, which is formally related to the starting molecule by a missing hydrogen atom. From X‐ray diffraction studies on single crystals it follows that the new compound has almost C2 point symmetry (the twofold axis intersecting the tin‐tin bond) and that this tin‐tin bond is the fusion edge of anellated fivefold Sn‐Sn‐N‐Si‐C rings. The bond connecting the almost tetrahedrally coordinated tin atoms (2.737(2) Å) is astonishingly very short. This feature is also reflected in the spectroscopic data (1H, 13C, 29Si, 119Sn‐NMR) of the compound with a coupling constant 1J (117Sn/119Sn) of 9529 Hz.
On the Mechanism of CO2 Insertion into the Mg‐N Bond of Molecular Mono‐ and Dinuclear Magnesium Compounds: A Quantum Chemical Study
Authors: Himmel Hans‐Jörg
Published: October 2007

Herein the mechanism for CO2 fixation by alkylmagnesium amides and magnesium bisamides is analyzed on the basis of DFT (density functional theory) calculations relying on the functionals BP86 and B3LYP in combination with a TZVPP basis set. Monomeric as well as dimeric compounds were considered, and prior to the CO2 reactions the thermodynamics of several equilibria (monomer‐dimer, disproportionation) is analyzed. Additional calculations were performed to study the mechanism for CO2 fixation in the presence of a chelating donor molecule, namely ethylene diamine, which preferentially complexes the monomeric alkylmagnesium amide. On the basis of the calculations it is suggested that (i) for monomeric magnesium compounds CO2 insertion into the Mg‐N bonds proceeds without a barrier to an intermediate featuring a four‐membered MgOCN ring and then with a relatively small barrier to the carbamate, (ii) for dinuclear magnesium compounds CO2 insertion is opposed by a significant barrier, and (iii) the addition of donor ligands which coordinate to the monomeric species shifts the monomer‐dimer equilibrium to the monomer side, and in addition leads to direct carbamate formation without any intermediate stage and with no reaction barrier. The studies might be of interest for a better understanding of enzymatic reactivity.
Synthese und Metallierung des Diphosphanyldisilans iPr4Si2(PH2)2, des zyklischen Silylphosphans (iPr2Si)3PH sowie des zyklischen Siloxylphosphans tBu2Si(OSiiPr2)2PH
Authors: von Hänisch Carsten , Traut Stephan , Stahl Sven
Published: October 2007

Synthesis and Metalation of the Diphosphanyldisilane iPr4Si2(PH2)2, of the cyclic Silylphosphane (iPr2Si)3PH as well as of the cyclic Siloxylphosphane tBu2Si(OSiiPr2)2PH

The 1,2‐diphosphanyldisilane iPr4Si2(PH2)2 (1) was obtained from the reaction of iPr4Si2Cl2 with [Li(dme)PH2]. Whereas reactions of [Li(dme)PH2] with the 1,3‐dichlortrisilane iPr6Si3Cl2 and the 1,5‐dichlortrisiloxane tBu2Si(OSiiPr2Cl)2 yield the cyclic compounds (iPr2Si)3PH (2) and tBu2Si(OSiiPr2)2PH (3). The reaction of 1 with AlEt3 produced the polycyclic compound [iPr4Si2{P(H)AlEt2}{PAlEt}]2 (4), by reactions of 2 and 3 with nBuLi the tricyclic compounds [(iPr2Si)3PLi(dme)]2 (5) and [tBu2Si(OSiiPr2)2PLi(Et2O)]2·C7H8 (7) were obtained. Reactions of these lithium compounds with Me3SiCl produced the tertiary, cyclic silylphosphanes (iPr2Si)3PSiMe3 (6) and tBu2Si(OSiiPr2)2PSiMe3 (8).
Enantiopure Salen‐Type Zinc Complexes
Authors: Meyer Nils , Roesky Peter W.
Published: October 2007

The first structurally characterized salen complexes of zinc having the chiral 1,2‐(R,R)‐diamino‐1,2‐diphenylethane as bridge between the two salicylaldehyde units were prepared. Treatment of (R,R)‐bis(salicylidene)‐1,2‐diphenylethylenediamine (1) with ZnEt2 resulted in the enantiomeric pure salen zinc complex ‐di[(R,R)‐(N,N′)‐bis(salicylidene)‐1,2‐diphenylethylenediamino)zinc(II)] (2). Compound 2 is a dimer in the solid state having a Zn‐O‐Zn‐O plane in the center of the molecule. In contrast, reaction of the more bulky (R,R)‐bis(3,5‐di‐tert‐butylsalicylidene)‐1,2‐diphenylethylenediamine (3) with ZnMe2 leads to the monomeric compound [(R,R)‐(N,N′‐bis(3,5‐di‐tert‐butylsalicylidene)‐1,2‐diphenylethylenediamino)(dietylether)zinc(II)] (4). In addition to the salen ligand one molecule of diethyl ether is bound resulting in a penta‐fold coordinated zinc atom.
On the Mechanisms of Electride Induced Synthesis of Ytterbium Carbazolates, Formation of Coordination Polymers by Condensation and Polymer Degradation by Chemical Scissors
Authors: Müller‐Buschbaum Klaus , Zurawski Alexander
Published: October 2007

Dissolution of ytterbium metal in liquid ammonia in the presence of carbazole at low temperatures and subsequent treatment with N‐phenylpiperazine gives single crystalline [Yb(Cbz)2(NH3)4] · 3Phpip (Cbz− = carbazolate anion, C12H8N−, Phpip = N‐phenylpiperazine, (C6H5)C4H8NNH). The highly air and moisture sensitive crystals are prone to release ammonia but can be successfully shielded in the interior of large crystals of CbzH · Phpip, a co‐crystallization of both ligands, whose crystal structure is also presented. Further heating transforms the monomeric molecules [Yb(Cbz)2(NH3)4] into dimeric [Yb2(Cbz)4(NH2)2(NH3)4] · 3CbzH and their condensation accompanied by release of ammonia consequently leads to the coordination polymer $^{1}_{\infty}\rm [Yb_{2}(Cbz)_{4}]$. This reaction path is compared to a high temperature reaction route without electride formation. Synthesis in molten carbazole directly leads to the one‐dimensional coordination polymer. Subsequent treatment with N‐phenylpiperazine yields dimeric [Yb2(Cbz)4(Phpip)4] · 2Phpip and monomeric [Yb(Cbz)2(Phpip)3][Yb(Cbz)3(Phpip)2], the final step of the degradation reaction. It can be shown that N‐phenylpiperazine functions as chemical scissors at higher temperatures and as crystallization matrix at lower temperatures.
Synthesis and Crystal Structure of the New Quaternary Subnitride Na15Li8Ba12N6
Authors: Smetana Volodymyr , Babizhetskyy Volodymyr , Vajenine Grigori V. , Simon Arndt
Published: October 2007

The crystal structure of the new compound Na15Li8Ba12N6 has been determined from single‐crystal X‐ray diffraction data. It crystallizes in the trigonal system, space group $R{\bar 3}m$ with a = 12.3409(9) Å, c = 33.311(4) Å, Z = 3, and R1 = 0.037 (wR2 = 0.046) for 1912 reflections with Io>2σ(Io). The structure can be described as an fcc‐type packing of Na tetrahedrons with Li8Ba12N6 clusters and centered Na hexagons in chair conformation among them. These hexagons together with some tetrahedral vertices connect to parallel infinite layers. By analogy with quaternary Na/Ba/Ca subnitrides this structure can be also regarded as a “salt in metal”.
Structural Flexibility of Carboxylate Bridging Exemplified by a Series of μ‐Acetato Dizinc Complexes
Authors: Gil Miguel Alvariño , Maringgele Walter , Dechert Sebastian , Meyer Franc
Published: October 2007

A series of closely related dizinc acetato complexes [LZn2(OAc)](ClO4)2 has been prepared from an assortment of known (HL1 – HL3) and new (HL4 – HL6) binucleating compartmental pyrazolate‐based ligands that provide two tripodal tetradentate {N4}‐type binding pockets but differ by the type of N‐donor within the chelate side arms. Six complexes 1a, 1b, 2 – 5 have been characterized by X‐ray crystallography. In all cases the two zinc ions are five‐coordinate, are nested in the adjacent ligand compartments as anticipated, and are spanned by a μ1,3‐bridging acetate that is hosted within the bimetallic pocket. Significant flexibility of the μ1,3‐acetato ligand is inferred from the structural data, resulting in dislocations of the metal ions out of the pyrazolate plane as well as severe twisting and tilting of the acetate bridge with respect to the bimetallic scaffold. These different orientations of the bridging acetate cannot be distinguished by their IR spectra, in contrast to the different acetate binding modes known from the dynamic behaviour termed “carboxylate shift”. However, the high flexibility of the μ1,3‐acetate even without changes in its coordination mode may well be a prerequisite for reactivity patterns of acetate‐bridged bimetallic arrangements.
Characterization of Gold Clusters by Crystallization with Polyoxometalates: the Intercluster Compounds [Au9(dpph)4][Mo8O26], [Au9(dpph)4][PW12O40] and [Au11(PPh3)8Cl2]2[W6O19]
Authors: Schulz‐Dobrick Martin , Jansen Martin
Published: October 2007

Four intercluster compounds constituted of different gold clusters and polyoxometalates have been crystallized and their crystal structures been determined. Two crystal structures comprise the new gold cluster [Au9(dpph)4]3+ (dpph = 1,6‐ bis(diphenylphosphino)hexane) and an octamolybdate anion, but differ in the overall packing of the building blocks, which are mutually coordinated distorted square planar (1: Pnna, Z = 4, a = 26.381(2), b = 32.428(2), c = 22.951(2) Å; 2: Pnna, Z = 8, a = 44.182(6), b = 43.138(6), c = 19.631(3) Å). The same gold cluster was found in [Au9(dpph)4][PW12O40], which crystallizes in ${\rm P}{\bar 1}$, Z = 2, a = 17.450(2), b = 18.833(3), c = 31.590(4) Å, α = 77.967(2)°, β > = 76.724(2)°, γ> = 64.598(2)°. The overall packing can be related to the NaCl‐type structure. The building blocks of [Au11(PPh3)8Cl2]2[W6O19] are packed as in the anti‐CdI2‐type structure. The compound crystallizes in ${\rm P}{\bar 1}$, Z = 1, a = 17.201(2), b = 18.154(2), c = 27.786(3) Å, α = 88.752(2)°, β = 88.426(2)°, γ = 68.331(2)°.
Cationic Main Group Element Cages of Germanium(II) and Tin(II) Consisting of 3,5‐Di(t‐butyl) Substituted Pyrazolyl Ligands in the Bridging Position
Authors: Krummenacher Ivo , Oschwald Claudia , Rüegger Heinz , Breher Frank
Published: October 2007

The transamination reaction of [Ge{N(SiMe3)2}2] with two equivalents of 3,5‐di(t‐butyl)pyrazole H(3,5‐tBu2pz) yielded the homoleptic germanium(II) pyrazolyl compound 4. Treatment of 4 and its analogous tin(II) compound 1 with triflic acid (HOTf) in diethyl ether afforded cationic, triply pz‐bridged cages of the general formula [E(μ2‐3,5‐tBu2pz)3E]+OTf− (E = Ge 5, Sn 6) in good yields. The sterically demanding t‐butyl substituted μ2‐pyrazolyl bridges adopt a skew arrangement with respect to the E···E vector in the solid state. DFT calculations were performed on the cage compounds 5 and 6 in order to elucidate the influence of the tilting of the pyrazolyl ligands as well as a weak coordination of the triflate counter anion in 6 on the intramolecular element element distances within the cationic moieties.
Synthesis and Structural Characterization of β‐Diketiminato Yttrium Complexes and their Application in Epoxide/CO2‐Copolymerization
Authors: Lazarov Boyan B. , Hampel Frank , Hultzsch Kai C.
Published: October 2007

The β‐diketiminato yttrium complexes [(BDIPh)2Y{N(SiHMe2)2}] (1, BDIPh = [PhNC(Me)CHC(Me)NPh]−), [(BDIPh)3Y] (2), and [(C5Me5)(BDIPh)Y{N(SiHMe2)2}] (4) are available via amine elimination starting from (BDIPh)H and either [Y{N(SiHMe2)2}3(THF)2] or [(C5Me5)Y{N(SiHMe2)2}2(THF)] (3). X‐ray crystallographic analysis of complexes 1 and 4 revealed a η5 coordination mode for the β‐diketiminato ligand, whereas the distorted octahedral complex 2 displayed pure κ2 coordination. Complex 3 was also structurally characterized. 1, 3, and 4 are moderately active catalysts in the copolymerization of cyclohexene oxide and CO2. Complex 3 was the most active system (TOF up to 33 h−1 at 75 °C, 8.5 atm CO2) and gave the highest molecular weight and narrowest polydispersity (Mn = 12600 g mol−1, Mw/Mn = 1.6).
Magnetization Studies of Superconductivity in a Molecular Metal Cluster Compound
Authors: Bono D. , Bakharev O.N. , Schnepf A. , Hartig J. , Schnöckel H. , de Jongh L. J.
Published: October 2007

Magnetization studies of the superconducting phases of two representative examples of the metal cluster compounds [Ga84{N(SiMe3)2}20‐Li6Br2(thf)20]·2toluene are presented. These materials can be seen as self‐organized nanostructures, composed of identical nanosized Ga84 metal particles arranged in a crystalline ordered 3‐dimensional array with a weak interparticle charge transfer. The compounds undergo transitions to bulk superconductivity of type II below Tc ≈ 7 – 8 K. The lower and upper critical fields Bc1 and Bc2 vary greatly between samples, which can be attributed to different concentrations of lattice defects arising from toluene deficiency.
Towards Rhodium and Iridium Complexes Containing the Secondary Phosphane Ligand tBu2PH
Authors: Böttcher Hans‐Christian , Graf Marion , Karaghiosoff Konstantin , Mayer Peter
Published: October 2007

The reactions of [{M(μ‐Cl)(η4‐cod)}2] (M = Rh, 1a; M = Ir, 1b; cod = 1,5‐cyclooctadiene) and [Rh(acac)(olefin)2] (acac = acetylacetonate; olefin = ethene, 3a; olefin = cis‐cyclooctene = coe, 3b) with tBu2PH in dichloromethane at room temperature were investigated, and the compounds [MCl(tBu2PH)(η4‐cod)] (M = Rh, 2a; M = Ir, 2b) as well as [Rh(acac)(tBu2PH)2] (4) were obtained in good yields. Furthermore, a one‐pot synthesis of trans‐[IrCl(C2H4)(tBu2PH)2] (6b) starting from [{Ir(μ‐Cl)(coe)2}2] (5), ethene and tBu2PH is described. All novel complexes were characterized using spectroscopic methods and the molecular structures of 2b, 6b, and trans‐[RhCl(C2H4)(tBu2PH)2] (6a) determined using X‐ray crystallography.
Synthese und Kristallstruktur der Verbindung [(C4H9)3(CH3)N]2[(WOCl4)2C4H8O2]
Authors: Okrut Alexander , Feldmann Claus
Published: October 2007

Synthesis and Crystal Structure of the Compound [(C4H9)3(CH3)N]2[(WOCl4)2C4H8O2]

By reacting WCl6, elemental potassium and 18‐crown‐6 in the ionic liquid [(C4H9)3(CH3)N][N(SO2CF3)2], [(C4H9)3(CH3)N]2 [(WOCl4)2C4H8O2] containing pentavalent tungsten is formed. The novel compound is yielded with transparent bluish crystals. Concerning to X‐ray diffraction analysis based on single crystals, [(C4H9)3(CH3)N]2 [(WOCl4)2C4H8O2] crystallizes triclinic ($P{\bar 1}$; a = 998.0(2); b = 1145.0(3); c = 1153.0(3) pm; α = 82.51(3)°; β = 65.31(3)°; γ = 70.80(3)°; Z = 1). The anion consists of two distorted WO2Cl4‐octahedra, which are bridged by a shared 1,4‐dioxane molecule.
Syntheses and Crystal Structures of Linear and Zig‐zag 1D Coordination Polymers with Schiff‐base N,N′‐Type Ligands
Authors: Wang Qing , Liang Bing , Zhang Jian‐Yong , Pan Mei , Kang Bei‐Sheng , Su Cheng‐Yong
Published: October 2007

Assembly of the Schiff‐base ligands 1,4‐bis(3‐pyridyl)2,3‐diaza‐1,3‐butadiene (N3Py) and 1,4‐bis(4‐pyridyl)‐2,3‐diaza‐1,3‐butadiene (N4Py) with different transition metal salts afforded four zig‐zag and two linear one‐dimensional (1D) chain coordination polymers, namely {[Hg(N3Py)Cl2]·CHCl3}n (1), [Hg(N3Py)I2]n (2), [Hg(N4Py)I2]n (3), {[Zn(N3Py)(NO3)2H2O]·H2O}n (4), {[Ag2(N3Py)2]·(CF3SO3)2}n (5) and {[Zn(N4Py)]·(C7H7SO3)2· (C2H5OH)2]n (6). These polymeric structures have been characterized by the single‐crystal X‐ray diffraction, FT‐IR and X‐ray powder diffraction measurements. The crystal packing fashions of these 1D chains have been analyzed, which indicates that the difference of the ligands and counter anions could significantly affect the stacking modes of these 1D chains in the crystal lattice, thus resulting in different hosting behaviors of the solvated molecules and anions. The thermal stability of complexes 1 and 6 was investigated by thermogravimetric measurements. The solid‐state phase purity has been checked by X‐ray powder diffraction measurements.
Syntheses, Crystal Structures, UV‐Vis Spectra and First NMR Spectra of New Potassium Salts of Chalcogenogermanates
Authors: Melullis Maike , Dehnen Stefanie
Published: October 2007

Single‐crystalline K+ salts of chalcogenogermanate anions and their corresponding hydrates have been prepared. K4[GeS4] (1), K4[GeSe4] (2), [K4(H2O)][GeS3(OH)] (3), [K4(H2O)4][GeSe4] (4), [K4(H2O)2][GeTe4] (5) and [K4(H2O)3][Ge2Se6] (6) were characterized by means of X‐ray diffractometry and optical absorption spectroscopy. Additionally, first NMR‐spectra of chalcogenogermanate salts are presented for 4 – 6.
Diamino Monosaccharide Ligands in Group 6 Carbonyl Complexes
Authors: Fowelin Christian , Matyja Anna , Schmidt Michael , Heck Jürgen
Published: October 2007

The reaction of methyl‐2,3‐diamino‐4,6‐O‐benzylidene‐2,3‐dideoxy‐α‐D‐glucopyranoside with the hexacarbonyl complexes of chromium, molybdenum and tungsten results in three new chiral tetracarbonyl complexes containing a diamino monosaccharide ligand. They are characterized by means of 1H, 13C NMR and infrared spectroscopy as well as single crystal X‐ray diffraction analysis.
Reactions of Coinage Metal Salts with a Mixed Sulfonic/Carboxylic Acid Anhydride
Authors: Shi Weifeng , Zhang Le , Shafaei‐Fallah Maryam , Rothenberger Alexander
Published: October 2007

The synthesis and structures of four new compounds are reported. [Cu2(2‐sba)(dppm)2] (1), [Ag4(2‐sba)2(PPh3)4] (2), [Ag2(2‐sbaH)2(PPh3)4] (3), [Ag(2‐sbaH)(PPh3)3] (4) (2‐sbaH2 = 2‐sulfobenzoic acid) were prepared by treatment of 2‐sulfobenzoic acid anhydride with metal salts under anhydrous conditions (1, 2) and in the presence of water (3, 4).
Kohlenwasserstoffverbrückte Metallkomplexe. LI. Ein Bis(ferrocenyl‐1,3‐diketonat)‐Kupfer(II)‐Chelatkomplex als Wirt für Calcium‐ und Alkalimetallionen
Authors: Woisetschläger Oliver E. , Scheurer Andreas , Saalfrank Rolf W. , Beck Wolfgang
Published: October 2007

Hydrocarbon Bridged Metal Complexes. LI. A Bis(ferrocenyl‐1,3‐diketonate) Chelate Copper(II) Complex as Host for Calcium and Alkali‐Ions

The reactions of the ferrocene (Fc) containing bis(ferrocenyl‐1,3‐diketone) FcC(O)CH=C(OH)‐C(OH)=CHC(O)Fc with copper2+ ions in the presence of calcium, sodium or potassium salts yield complexes in which bis(1,3‐diketonate)copper chelates act as hosts for Ca2+, Na+ or K+ ions.
Investigations on Chemical Vapour Deposition of Magnesium‐Boron‐Containing Metal‐Organic Precursors
Authors: Mathur Sanjay , Rügamer Thomas , Braunschweig Holger , D'Andola Giovanni
Published: October 2007

Single‐molecular magnesium‐boron precursors [Mg(C3H6‐BC8H14)2] and [Mg{C3H6‐B(C6H11)2}2] were applied in chemical vapour deposition processes and characterized using SEM, XRD, XPS, AFM and MS methods towards their fragmentation behaviour, film morphology, phase formation and film composition. Depositon procedures in a temperature range from 500 to 1000 °C produced smooth and thin films with Mg and B in the ration 1:2. It could be shown that the contamination of the deposits by a considerably fraction of residual carbon could be reduced by post‐deposition in‐situ tempering or additionally sputter processes which may lead to improved deposition of MgB2‐films.
Reaktion von (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamin mit Berylliumchlorid. Kristallstrukturen von (R,R,SN,SN′)‐[(C12H26N2)BeCl2] und (R,R,SN,SN′)‐[(C12H26N2)BeCl(N3)]
Authors: Neumüller Bernhard , Dehnicke Kurt
Published: October 2007

Reaction of (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamine with Beryllium Chloride. Crystal Structures of (R,R,SN,SN′)‐[(C12H26N2)BeCl2] and (R,R,SN,SN′)‐[(C12H26N2)BeCl(N3)]

(R,R)‐(N,N′)‐diisopropylcyclohexyl‐1,2‐diamine reacts with equimolar amounts of BeCl2 in dichloromethane suspension to give the donor acceptor complex (R,R,SN,SN′)‐[(C12H26N2)BeCl2] (1). The reaction of 1 with excess trimethylsilylazide in dichloromethane solution leads to the formation of the azido derivative (R,R,SN,SN′)‐[(C12H26N2)BeCl(N3)] (2). Both complexes are characterized by X‐ray diffraction and by IR spectroscopy.

1 · 0.5CH2Cl2: Space group P6122, Z = 6, lattice dimensions at 193 K: a = b = 1390.3(1), c = 1624.8(1) pm, R1 = 0.0509. In the chiral complex 1 the BeCl2 unit forms a BeN2C2 chelate ring with Be–N distances of 199.8(4) pm. The molecules are associated via Cl···H–N hydrogen bridges along [001].

2: Space group P21, Z = 6, lattice dimensions at 193 K: a = 1501.7(2), b = 968.6(2), c = 1629.2(4) pm, β = 90.03(3)°, R1 = 0.0981. The structure of 2 consists of three independent chiral units (R,R,SN,SN′)‐[(C12H26N2)BeCl(N3)], which are associated via Cl···H–N and Nα···H–N hydrogen bridges along [100], Nα being Nα atoms of the azido groups.
The Gap at the Top: Relative Occupational Earnings Disadvantages of the Black Middle Class
Authors: Cotton Jeremiah
Published: October 2007

Data are presented in this article indicating that the disparity in the earnings of blacks and whites in upper level white-collar occupations is greater than that between their counterparts in blue-collar occupations. Moreover it appears that very little of the racial earnings differences in either occupational category can be explained by so-called human capital differences.
On the 100th Anniversary of Sterile Catgut Kuhn: Franz Kuhn (1866–1929) and the Epistemology of Catgut Sterilization
Authors: Dietz Ulrich A. , Kehl Franz , Hamelmann Wulf , Weißer Christoph
Published: October 2007

The long road to effective catgut sterilization began with the work of Lord Joseph Lister (1867) and did not end until 40 years later. At the end of the nineteenth century dozens of different techniques were used to “sterilize” catgut, by immersing the cord in a cold chemical solution, by exposing it to steam, or by a combination of the two techniques, yet none of these approaches offered the ultimate solution. One of the many physicians working on the catgut problem at that time was the German surgeon Franz Kuhn (1866–1929), best known as a pioneer of intubation anesthesia. This review offers a brief biographical sketch of Kuhn’s life and career on the occasion of the centenary of Sterile Catgut Kuhn. The goal of the present study is to describe several landmarks in the development of the catgut sterilization method. To explain this process, two approaches are taken: first, an analysis to see whether the character traits of the typical surgeon at that time provided the soil in which innovation could thrive, and second, an epistemological examination of the conceptual models for the attainment of knowledge current at that time. Perspectives for the future are explored in light of the “imperative of responsibility” of Hans Jonas.