bluuebunny/crossref_metadata_2025 huggingface dataset:
The structural wear of road pavements: an assessment of the fourth power law on the A1(M) motorway in County Durham
Authors: Rhodes A. H. , Suara A. M.
Published: July 2007

This Paper records the results of an audit which has examined the structural performance of a heavily trafficked public road in Durham County. A detailed history of the construction, maintenance and classified traffic flows for the road was available from Durham County Council (DCC) and, together with typical axle loads from the Traffic Loading Unit, University of Newcastle upon Tyne, the study estimated actual exponent values for sections of public road assuming that a power law relationship existed between structural wear and wheel load. The study showed that the actual power exponent values were between 0.02 to 7.16 and, for exponent values that were significantly different to 4, an initial pavement design life of 20 years would no longer minimize whole life cost. The consequences of this finding are far-reaching for the design and management of road pavements.
Public Health Perspectives on Surveillance for Periodontal Diseases
Authors: Tomar Scott L.
Published: July 2007

Public health surveillance has been defined as the ongoing systematic collection, analysis, interpretation, and dissemination of data regarding a health‐related event for use in public health action to reduce morbidity and mortality and to improve health. Surveillance is an essential element of public health program infrastructure. The desirable attributes of public health surveillance systems are simplicity, flexibility, data quality, acceptability, sensitivity, predictive value positive, representativeness, timeliness, and stability. However, surveillance for periodontal diseases is nearly non‐existent at state, county, or local levels in the United States. That void largely is the result of the current approach to monitoring periodontal diseases in populations, which generally requires resource‐intensive primary collection of clinical data using relatively invasive methods. One potential alternative to that approach to periodontal disease surveillance is the use of self‐reported data collected through population surveys. Seventeen identified studies have tested the validity of individual questionnaire items for their sensitivity, specificity, and predictive values positive and negative against a range of clinical operational definitions for periodontitis. No individual items seem to be robust or valid markers for clinically determined periodontitis. However, it is possible that a multivariable statistical modeling approach, which includes variables on signs, symptoms, and established risk factors, could improve the sensitivity and specificity of that approach. An example is given of a model‐based approach to public health surveillance that has been effective in quantifying the impact of a public health problem, monitoring trends between and within states, and supporting advocacy and policy development by state and local governments.
Piezosurgical Treatment of Unicystic Ameloblastoma
Authors: Covani Ugo , Barone Antonio
Published: July 2007

Background: This case report describes a 22‐year‐old female who was referred with a radiolucent lesion between her mandibular right molars. The original radiographic image suggested an odontogenic cyst.

Methods: The surgical enucleation and osteotomy of the residual cavity were performed with a piezoelectric knife. Histologic analysis revealed the lesion was a unicystic ameloblastoma that showed no evidence of epithelial invasion in the connective tissue wall, and it appeared to be contained within the cystic cavity with an intraluminal projection showing features of an ameloblastoma. The patient refused any further surgical treatment. In consideration of the pathological result (no presence of invasive epithelial cells in the connective tissue wall of the cyst), a wait‐and‐see policy was proposed to the patient, with more extensive surgical treatment only if a recurrence was noted.

Results: The patient has been followed clinically and radiographically at 6‐month intervals for 5 years. There have been no signs of recurrence.

Conclusion: Therefore, the piezoelectric knife could be considered a promising device in the treatment of odontogenic tumors.
Timing Affects the Clinical Outcome of Adjunctive Systemic Antibiotic Therapy for Generalized Aggressive Periodontitis
Authors: Kaner Doğan , Christan Claudia , Dietrich Thomas , Bernimoulin Jean‐Pierre , Kleber Bernd‐Michael , Friedmann Anton
Published: July 2007

Background: Systemic antibiotics improve the outcome of scaling and root planing (SRP) in patients exhibiting severe periodontitis. This study evaluated the influence of timing of adjunctive systemic antibiotics in the sequence of periodontal therapy.

Methods: Two cohorts of patients with generalized aggressive periodontitis and treated by SRP, adjunctive antibiotics, and supportive periodontal therapy (SPT) were analyzed retrospectively. Cohort A (17 patients; 36 ± 5 years of age) received systemic amoxicillin/metronidazole immediately after SRP (“immediate”); cohort B (17 patients; 36 ± 4 years of age) received the same regimen 3 months after SRP, following SPT, including subgingival reinstrumentation (“late”). Clinical parameters, including probing depth (PD), relative attachment level (RAL), bleeding on probing (BOP), and suppuration, were recorded with a pressure‐sensitive electronic probe at baseline and 3 and 6 months after SRP.

Results: Significant time*group interactions were found for all clinical parameters except BOP, i.e., timing of antibiotic therapy affected the course of clinical changes over time. Immediate antibiotic therapy produced significantly higher initial changes (0 to 3 months) in PD and RAL. Late antibiotic therapy at 3 months resulted in additional significant improvements in all clinical parameters between 3 and 6 months. In initially deep sites (baseline PD >6 mm), improvements in PD and RAL over 6 months were significantly higher with immediate antibiotic therapy compared to late antibiotic therapy.

Conclusion: Within the limits of a retrospective analysis, these findings indicate that administration of amoxicillin/metronidazole immediately after initial SRP provides more PD reduction and RAL “gain” in initially deep sites than late administration at SPT with reinstrumentation after 3 months.
Academic Cheating as a Function of Defense Mechanisms and Object Relations
Authors: Juni Samuel , Gross Julie , Sokolowska Joanna
Published: July 2007

This study examined relationships between academic cheating behaviors by using self-reports of past cheating behavior, providing a situational experiment with the opportunity to cheat, and evaluating defense mechanisms and object relations as measured by the Defense Mechanisms Inventory. Subjects included 75 female and 8 male university students ranging in age from 18 to 51 years ( M = 25.5, SD = 6.9). Analysis showed variations in students' self-reported cheating history relative to their measured object relations status and type of defense mechanisms. Actual cheating in the experimental setting was not significantly related to any of these variables. Findings are discussed based on a critique of heterogeneity of the cheating construct.
Dimensionality of the Pay Satisfaction Questionnaire: A Validation Study in Belgium
Authors: De Gieter S. , De Cooman R. , Pepermans R. , Caers R. , Bois C. Du , Jegers M.
Published: July 2007

This study examined the underlying dimensions of the Pay Satisfaction Questionnaire to test whether the robust 4-factor structure (Pay Level, Benefits, Raises, and Structure or Administration) often established in the United States can be generalized to other countries and cultures as well. Data of 4 samples (for-profit employees, nonprofit nurses, cultural centre employees, and nonprofit teachers) were analysed with confirmatory factor analyses. The results for the first 3 samples yielded support for the original 4-factor structure of the Pay Satisfaction Questionnaire. In the teachers' sample, the irrelevant Benefits items were excluded from the analysis, resulting in a 3-factor structure of pay satisfaction.
Moral Reasoning and Personality Traits
Authors: Mudrack Peter E.
Published: July 2007

Moral reasoning should not be clearly associated with measures of personality traits. Although this assumption pervades the moral reasoning literature, it may not always be true. This paper provides evidence that moral reasoning, as assessed with P scores of the Defining Issues Test, is indeed positively associated with five traits from the California Psychological Inventory: Achievement via Independence, Intellectual Efficiency, Tolerance, Responsibility, and Capacity for Status. Such relationships make conceptual sense, shed light on the meaning and implications of moral reasoning, call into question prevailing assumptions in the literature, and may encourage investigators to broaden the types of research questions asked in the context of moral reasoning.
Ethnic Identity and Risky Health Behaviors in School-Age Mexican-American Children
Authors: Love Ashley S. , Yin Zenong , Codina Edward , Zapata Jesse T.
Published: July 2007

The study examined the relationship between ethnic identity and risky health behaviors in 1,892 Mexican-American students ( M age=14.6, SD = 1.35; 50.3% male) in South Texas. The Ethnic Identity Scale assessed ethnic identity and questions from the Youth Risk Behavior Survey measured risky health behaviors (mixed use of alcohol and drugs, heavy drinking, driving under the influence, regular marijuana use, regular cigarette smoking, lack of regular exercise, not eating breakfast regularly, and carrying a gun or knife to school). Logistic regression tested the relationships between ethnic identity and report of risky health behaviors controlling for potential confounders (sex, free school lunch status, grade, and self-reported school grade). Adjusted odds ratio (AOR) and confidence intervals were calculated. Results indicated that being associated with Mexican-American cultural identity was significantly associated with a decreased mixed use of alcohol and drugs (AOR=.97), heavy drinking (AOR=.98), and regular marijuana use (AOR=.97). A stronger ethnic identity was protective against engaging in risky health behaviors among these Mexican-American adolescents.
Relationship between Students' Self-Assessment of Their Capabilities and Their Teachers' Judgments of Students' Capabilities in Mathematics Problem-Solving
Authors: Chen Peggy P.
Published: July 2007

The study examined the judgments made by four seventh-grade mathematics teachers of their 107 students' competence in solving mathematics problems. Simultaneously, the 107 students made self-efficacy judgments about their capability in solving mathematics problems. The two sets of judgments were tested for predicting students' mathematics performance. Also, students' prior mathematics achievement was studied for its influence on both teachers' and students' judgments and students' mathematics performance. Teachers were asked to make judgments of each student for every mathematics problem solved. Results were consistent with prior research indicating that students' mathematics self-efficacy beliefs were highly predictive of their performance. Path analysis indicated that the mathematics teachers' judgments were also highly predictive of students' performance and self-efficacy. In turn, these variables predicted students' postperformance judgments. Combining students' self-efficacy judgments and teachers' judgments of students increased predictiveness for students' mathematics performance. Educational implications were also discussed.
Detection of Feigned Memory Impairments Using a Chinese Word Task
Authors: Mak Ellen G. Y. , Lee Tatia M. C.
Published: July 2007

In this study the detection of feigned memory impairments was investigated using a forced-choice task with Chinese words as stimuli. Task difficulty on accuracy and response time and the faking strategies employed were examined for 85 participants, 42 men and 43 women, who were administered the experimental task. Following a simulation design, all participants performed under control and faking conditions. Their accuracy of performance and response times were measured. Analysis indicated significant differences on both outcome measures for the two conditions. Further, a significant difference in accuracy, but not in response time, among levels of task difficulty was observed. For classification accuracy, using the cut-off score criterion seemed more effective than using the below-chance criterion or response time. Implications for relying on chance criterion to identify deception are discussed.
Psychiatric Diagnoses of Patients Visiting a Sleep Disorder Clinic Due to Dyssomnias
Authors: Hsu Shih-Chieh , Liu Chia-Yih , Chen Ning-Hung
Published: July 2007

This study analyzed the demographic characteristics and psychiatric diagnoses of 90 consecutive patients who visited a sleep disorder clinic in Taiwan with complaints of insomnia (difficulty initiating or maintaining sleep, or nonrestorative sleep) or hypersomnia (excessive sleepiness as evidenced by either prolonged sleep episodes or daytime sleep episodes that occur almost daily). All subjects were interviewed using a sleep disturbance questionnaire and the structured Mini-International Neuropsychiatric Interview supplemented by the DSM-IV criteria for psychiatric diagnoses. Among 90 patients, 79 were classified as having insomnia and 11 had hypersomnia. 53 patients also had psychiatric diagnoses other than sleep disorders. Patients with insomnia had a significantly higher rate of comorbidities with other psychiatric diagnoses (65.8%) than did subjects with hypersomnia (9.1%). These results emphasize the importance of psychiatric evaluation of patients with complaints of sleep disturbance.
Who Uses eBay? A Preliminary Study
Authors: Yang Bijou , Lester David
Published: July 2007

Buying and selling items on eBay was predicted in a sample of 386 undergraduate students from two institutions by computer or Internet skills, year and, for buying items on eBay, sex.
Implications of 3-Yr.-Olds' Successful Performance on a No Conflict Version of the Dimensional Change Card Sort
Authors: Zelazo Philip David
Published: July 2007

Moriguchi and Itakura (2005) compared 3-yr.-old children's performance on the standard version of the Dimensional Change Card Sort with performance on a new, No Conflict version. Here, it is noted that the children's successful performance on the No Conflict version is consistent with existing theoretical interpretations of children's performance on the standard version.
Students' Machiavellianism and Motives for Communicating with Instructors
Authors: Martin Matthew M. , Myers Scott A. , Mottet Timothy P.
Published: July 2007

This study investigated the relationship between scores of college students ( N = 210, 114 women, 95 men, 1 unidentified; M age = 19.3 yr., SD = 2.8) on Machiavellianism and their motives for communicating with their instructors in the classroom. Students' Machiavellianism scores were positively but weakly related to three motives of Functional ( r = .22, p <.01), Excuse-making ( r = .16, p <.05), and Sycophancy ( r = .17, p <.05).
Preliminary Relation between Followers' Locus of Control and Organizational Citizenship Behaviors
Authors: Barbuto John E. , Bugenhagen Marilyn J.
Published: July 2007

This study estimated the relationship between followers' locus of control and organizational citizenship behaviors for a sample of 375 government employees, whose M age was 46 yr. 53% were women; 42% earned bachelor's degrees. Analyses showed a significant positive correlation of .35 between followers' locus of control and their organizational behaviors. More complex models and research designs are necessary to generalize.
Sex of Respondent and Credit Attitudes as Predictors of Credit Card Use and Debt Payment
Authors: McCall Michael , Eckrich Donald W.
Published: July 2007

Researchers have suggested there may be sex differences in attitudes towards credit card possession and use. Undergraduates, 41 men and 41 women, completed a survey regarding their attitudes towards credit, credit card use, and repayment. Analysis indicated sex played a significant moderating role between number of credit cards used and the importance of paying off monthly balances. Women possessed more credit cards than men and engaged in more frequent shopping. Number of credit cards increased with paying off of monthly balances. Data are discussed in terms of the importance of managing credit card debt in an increasingly cashless society.
Comment on Factorial Structure of the Kuwait University Anxiety Scale
Authors: Lester David
Published: July 2007

The Kuwait University Anxiety Scale was administered to 138 American college students and three meaningful factors identified, somewhat different from those identified by Abdel-Khalek in 2000.
Possible accumulation of non-active molecules of catalase and superoxide dismutase in S. cerevisiae cells under hydrogen peroxide induced stress
Authors: Bayliak Maria , Semchyshyn Halyna , Lushchak Volodymyr
Published: July 2007

The effect of hydrogen peroxide on the activities of catalase and superoxide dismutase (SOD) in S. cerevisiae has been studied under different experimental conditions: various H2O2 concentrations, time exposures, yeast cell densities and media for stress induction. The yeast treatment with 0.25–0.50 mM H2O2 led to an increase in catalase activity by 2–3-fold. At the same time, hydrogen peroxide caused an elevation by 1.6-fold or no increase in SOD activity dependently on conditions used. This effect was cancelled by cycloheximide, an inhibitor of protein synthesis in eukaryotes. Weak elevation of catalase and SOD activities in cells treated with 0.25–0.50 mM H2O2 found in this study does not correspond to high level of synthesis of the respective enzyme molecules observed earlier by others. It is well known that exposure of microorganisms to low sublethal concentrations of hydrogen peroxide leads to the acquisition of cellular resistance to a subsequent lethal oxidative stress. Hence, it makes possible to suggest that S. cerevisiae cells treated with low sublethal doses of hydrogen peroxide accumulate non-active stress-protectant molecules of catalase and SOD to survive further lethal oxidant concentrations.
The atrial natriuretic peptide (ANP) system in the pronephros and mesonephros of Bufo bufo larvae
Authors: Tei Simonetta , Salamida Sonia , Vagnetti Daniela
Published: July 2007

In this study on the excretory apparatus of the Bufo bufo larvae, the ultrastructural features and the atrial natriuretic peptide (ANP)-system were examined using cytochemical and immunocytochemical methods. The early embryonic kidney, the pronephros, is replaced by a later stage, the mesonephros. The pronephros degenerates at the time of metamorphosis and the mesonephros becomes the functional kidney in the adult. Both these organs are targets for ANP, demonstrated by the presence of the specific receptors, indirectly highlighted by the cytochemical localization of the guanylate cyclase in the presence of exogenous atrial natriuretic peptide. This study concluded that the mesonephros produces ANP and thus clusters of cells containing ANP-like granules, positive to the anti-α ANP immunolocalization, were present along the mesonephric proximal tubule. The atrial natriuretic peptide system carries out an important osmoregulatory role in the excretory apparatus.
Recycled PET nanocomposites improved by silanization of organoclays
Authors: Kráčalík Milan , Studenovský Martin , Mikešová Jana , Sikora Antonín , Thomann Ralf , Friedrich Christian , Fortelný Ivan , Šimoník Josef
Published: July 2007

Recycled PET/organo‐modified montmorillonite nanocomposites were prepared via melt compounding as a promising possibility of the used beverage bottles recovery. According to our previous work, the three suitable commercial organoclays Cloisite 25A, 10A, and 30B were additionally modified with [3‐(glycidyloxy)propyl]trimethoxysilane, hexadecyltrimethoxysilane and (3‐aminopropyl)trimethoxysilane. The selected organoclays were compounded in the concentration 5 wt % and their degree of intercalation/delamination was determined by wide‐angle X‐ray scattering and transmission electron microscopy. Modification of Cloisite 25A with [3‐(glycidyloxy)propyl]trimethoxysilane increased homogeneity of silicate layers in recycled PET. Additional modification of Cloisite 10A and Cloisite 30B led to lower level of delamination concomitant with melt viscosity reduction. However, flow characteristics of all studied organoclay nanocomposites showed solid‐like behavior at low frequencies. Silanization of commercial organoclays had remarkable impact on crystallinity and melt temperature decrease accompanied by faster formation of crystalline nuclei during injection molding. Thermogravimetric analysis showed enhancement of thermal stability of modified organoclays. The tensile tests confirmed significant increase of PET‐R stiffness with organoclays loading and the system containing Cloisite 25A treated with [3‐(glycidyloxy)propyl]trimethoxysilane revealed combination of high stiffness and extensibility, which could be utilized for production of high‐performance materials by spinning, extrusion, and blow molding technologies. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Durable antimicrobial finish of cotton fabrics
Authors: Bang Eun S. , Lee Eui S. , Kim Seung I. , Yu Young H. , Bae Soon E.
Published: July 2007

Cotton fabrics were treated with Biopag, which does not have any functional groups that are reactive toward cellulose, using crosslinking agents or a binder, for the purpose of imparting a durable antimicrobial finish. In this respect, it was found that the crosslinking agents were more effective than the binder. It was confirmed by FT‐IR that the characteristic split peaks of Biopag were still seen even after repeated launderings. The crosslinking agents deteriorated the whiteness and tensile strength of the Biopag‐treated cotton fabrics, while the wrinkle recovery angles (WRAs) were significantly improved. The one‐step padding of Biopag and the crosslinking agent was found to be superior to the two‐step padding method in which Biopag padding was followed by padding of crosslinking agent in respect of WRA, whereas the whiteness and tensile strength were vice versa. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
When bonuses backfire: an inaction inertia analysis of procrastination induced by a missed opportunity
Authors: Pittman Thane S. , Tykocinski Orit E. , Sandman‐Keinan Ruty , Matthews Pamela A.
Published: July 2007

An inaction inertia analysis of procrastination was used to generate the prediction that using bonuses to encourage early task completion will have two opposing effects, encouraging early task completion by some but also inducing procrastination for those who miss the bonus. Study 1 showed that the addition of bonuses for early completion produced both of these effects and also led to overall task completion rates that were either equal to (large bonus) or actually less than (medium and small bonuses) those obtained by simply establishing a completion deadline with no bonus. In Study 2, a lottery methodology was used to manipulate the size of a missed bonus for all participants. Even under these conditions of reduced personal responsibility the larger missed bonus led to increased procrastination as predicted by the inaction inertia analysis. Possible mediating processes based on anticipated regret and perceived fairness were discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Total synthesis by modern chemical ligation methods and high resolution (1.1 Å) X‐ray structure of ribonuclease A
Authors: Boerema David J. , Tereshko Valentina A. , Kent Stephen B. H.
Published: July 2007

The total chemical synthesis of RNase A using modern chemical ligation methods is described, illustrating the significant advances that have been made in chemical protein synthesis since Gutte and Merrifield's pioneering preparation of RNase A in 1969. The identity of the synthetic product was confirmed through rigorous characterization, including the determination of the X‐ray crystal structure to 1.1 Angstrom resolution. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90:278–286, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Impact of the Merrifield solid phase method on the design and synthesis of selective agonists and antagonists of oxytocin and vasopressin: A historical perspective
Authors: Manning Maurice
Published: July 2007

This tribute to Bruce Merrifield traces the author's fortuitous path in 1964 from Vincent du Vigneaud's laboratory to the laboratory of D. W. Woolley to learn the solid phase method and then to his first faculty position in the Department of Biochemistry, McGill University, Montreal in 1965. It recalls the key roles played from early 1966 to July 1967 by Bruce Merrifield, John Stewart, Arnold Marglin, Herb Takashima, and Vincent du Vigneaud in providing key advice to the author's efforts to use the solid phase method to synthesize oxytocin; while simultaneously the du Vigneaud and Merrifield laboratories were collaborating on the solid phase synthesis of deamino‐oxytocin. Both syntheses were published in the same issue of the Journal of American Chemical Society in 1968. Also described is how this breakthrough impacted the author's scientific career: by leading to highly productive collaborative studies, initially with Wilbur H. Sawyer and subsequently with others, on the design and synthesis of selective agonists, antagonists, and radioiodinated ligands for oxytocin and vasopressin receptors. These syntheses were greatly facilitated by the contributions of highly talented graduate students, research technicians, and visiting peptide chemists from Hungary, England, Poland, Bulgaria, and China. Many of these peptides have become very valuable pharmacological tools in studies on the peripheral and central effects of oxytocin and vasopressin: further attesting to the profound impact of the solid phase method as the cornerstone for all the discoveries, which he and his collaborators and coworkers have made over the past 40 years. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 90: 203–212, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Synthesis and Bonding in Hybrid Diborolyl/Boranyl and Thiaboranyl Triple‐Decker Compounds – Electronic Contribution of Heteroborane Cluster Ligands in Complexes
Authors: Weinmann Wolfgang , Pritzkow Hans , Siebert Walter , Sneddon Larry G.
Published: July 2007

The three‐component reaction of [(η5‐C5H5)Co(η5‐(CEt)2(BEt)2CMe)]−, CoCl2and B9H−14(7) yields the triple‐decker complex [(η5‐C5H5)Co{μ,η5‐(CEt)2(BEt)2CMe}‐6‐Co(B9H13)] (8) with a terminal B9H13ligand contaning two cobalt–boron‐bridging hydrogen atoms. Analogously, (6‐H)−, CoCl2, andarachno‐6‐SB9H−12(10) react to give the triple‐decker [(η5‐C5H5)Co{μ,η5‐(CEt)2(BEt)2CMe}‐1‐Co‐2‐(SB9H9)] (11). The analogous reaction with the heteroboranyl anion arachno‐6,8‐S2B7H8−leads to the loss of one boron atom, forming the air‐stable triple‐decker complex [(η5‐ C5H5)Co{μ,η5‐(CEt)2(BEt)2CMe}‐7‐Co‐6,8‐(S2B6H8)] (12). The X‐ray structure determination shows that the dithiacobaltaborane fragment in12has an arachno cluster geometry. The three‐component reaction of (6‐H, CoCl2, and arachno‐2,3‐S2B9H10−yields the expected triple‐decker [(η5‐C5H5)Co{μ,η5‐(CEt)2(BEt)CMe}Co‐6,8‐(S2B9H9)] (15), and surprisingly the sandwich complex (η5‐C5H5)Co‐6,8‐(S2B9H9) (16). The constitutions of the new compounds are based on NMR and MS data. A rule is described regarding the electron donation of heteroboranyl cluster ligands in metal complexes.
Preparation, Properties, and Reactions, of Metal‐Containing Heterocycles, XCVI. Mono‐, Di‐ and Trinuclear Metallacycloalkanes of the Iron‐Triad
Authors: Lindner Ekkehard , Leibfritz Thomas , Fawzi Riad , Steimann Manfred
Published: July 2007

The reaction of the bis(triflates) [F3CSO3‐(CH)m‐O3SCF3] [m = 5–10, 12, 14, 16 (1a–i) with Na2[Os(CO)4] in dimethyl either affords the osmacycloalkanes 2a, 2b and 2f–i (m = 5, 6, 10, 12, 14, 16), diosmacycloalkanes 3a–i (m = 5‐10, 12, 14, 16), and triosmacycloalkanes 4a–i (m = 5–10, 12, 14, 16). The structure of 3f was investigated by an X‐ray structural analysis. This 22‐membered disomacycle crystallizes in the space group Pā with Z = 1. If the unsaturated cis‐4‐octen‐1,8‐diyl bis(trifluoromethanesulfonate) (5) is treated with Na2[Os(CO)4] the diosmacyclooctadeca‐5,14‐diene 6 is obtained. By treating the bis(triflates) 1a, b with Na2[Fe(CO)4] the corresponding ferracycloalkanes are formed only in situ. Insertion of carbon monoxide into the M–C σ bonds leads to the cyclic ketones 7a, d and to the diketone 8d.
New Five‐ and Six‐Coordinate Nitrosylosmium(0) and Nitrosylosmium(II) Complexes Prepared from the Stable 16‐Elektron Species [OsCl(NO)(PR)(PR3)2]
Authors: Werner Helmut , Flügel Ruth , Windmüller Bettina
Published: July 2007

The coordinatively unsaturated starting materials trans‐[OsCl(NO)PiPr3)2] (2) and trans‐ [(sCl(NO)(PiPr2Ph)2] (3), for which a new one‐pot synthesis is reported, react with isocyanides, SO2 and O2 to give the corresponding 1:1 adducts [OsCl(NO)(L)(P)(PiPr2R)2) (4–7). The corresponding methyleneosmium complex [OsCl(NO)(CH2)(PiPr3)2] (9), on treatment with SO2 and HCl, affords the six‐coordinate osmium(II) compounds [OsCl(NO)(K2(C,O)‐CH2S(O)O)()iPr3)2] (10) and [OsCl2(NO)(CH3(PiPr3)2]2] (11), respectively. The reactions of 2 and 3 with HCl, I2, CH3I, CH2CHBr, R'CO2H, PhSH, CH3OH, PhCOSH, and R'CHO lead by oxidative addition to the corresponding octahedral osmium(II) complexes [OsCl‐(NO)(X)(Y)(PiPr2R)2] (12–24). The initially formed compound [OsHCl(NO){SC(O)Ph}(PiPr3)2] (20a) rearranges smoothly to the more stable S‐bonded isomer [OsHCl(NO){OC(S)Ph}(PiPr3)2] (20b). Alkynyl(hydrid)‐ and diynyl(hydrido)‐osmium(II) complexes 20–31 and 34, 35 are obtained from 2 or 3 and HCCCO2/sb>Me, propargylic alcohols HCCCPh‐(R')OH or the diyne HCCCCCPh2OH. The compounds [OsHCl(NO)[CCCPh(R')OH)(PiPr3)2] (30, 31) react with aqueous HCl in benzene to give the η1‐allenylosmium(II) derivatives [OsCl2(NO)(η1‐CHCC(Ph)R'](PiPr3)2] (32, 33). [OsHCl(NO)(CCCCCPh2OH)(PiPR3)2] (34) has been characterized by X‐ray structural analysis.
Dinuclear Cobalt(II) Complexes of Pyrazole Ligands with Chelating Side Arms
Authors: Meyer Franc , Beyreuther Stefan , Heinze Katja , Zsolnai Laszlo
Published: July 2007

A series of pyrazole‐based potential ligands bearing polydentate amine substituents in the 3‐ and 5‐positions of the heterocycle has been synthesized [3,5‐bis(R2NCH2)‐pyzH R2N = Me2N(CH2)3NMe (2aH), [Me2N(CH2)3]2N (2bH), (Et2NCH2CH2)2N (2cH)]. Upon reaction with two equivalents of CoCl2 they form complexes LCo2Cl3 (3a–c; L = 2a–c, respectively) which are shown crystallographically to contain a dinuclear metal core bridged by both the pyrazolate unit and a chlorine atom, with each cobalt center carrying a further terminal chlorine atom. Two of the ligand side arms in 3b, c are dangling, thus leading to five‐coordination of the cobalt(II) centers in all cases. Addition of two equivalents of NaBPh4 to solutions of 3b, c induced coordination of the formerly dangling side arms to the metal centers by substitution of the terminal chlorine atoms. The resulting compounds [LCo2Cl](BPh4)2 (4b, c, respectively) were characterized by X‐ray structure analyses. They can be viewed as dinuclear linked versions of tran‐type complexes [(tran = tris(aminoalkyl)amine] with distorted trigonal‐bipyramidal coordination spheres around cobalt(II). Conformational analyses employing force‐field calculations were carried out for 4b, c in order to rationalize the conformations observed in the solid state with regard to the accessible conformational space.
Polynuclear Gold(I) Complexes of Functionalized Thiols and Dithiols
Authors: López‐De‐Luzuriaga José M. , Sladek Alexander , Schneider Wolfgang , Schmidbaur Hubert
Published: July 2007

Treatment of 2‐mercaptoaniline with {[(Ph3P)Au]3O}+ BF−4 leads to a regioselective auration to give the (2‐aminophenyl)sulfonium complex {(2‐H2NC6H4S[Au(PPh3)]2}+ BF−4 (1) as the sole product. With the same reagent, 4‐hydroxyphenyl)sulfonium salt 2, and 2‐mercaptopyridine is converted into the 2‐pyridylsulfonium salt 3. Dinuclear auration of the thiol functions is thus clearly favoured over the reaction at any of the other functional groups (–NH2, –py, –OH). As shown in earlier work, this is also true for HS‐functional carboxylic acids. With an excess of the oxonium reagent, however, 2‐mercaptosuccinic acid was now found to be converted into a tetranuclear complex with a doubly aurated sulfonium group and monoaurated carboxylate functions (4). Bis(2‐mercaptoethyl) ether and thioether react with the oxonium salt to give tetranuclear bis(sulfonium salts) 5, 6, with bifurcated {‐S[Au(PPh3)]2}+ groups at both ends. Structural studies of compounds 1, 5 and 6 showed the cations to be aggregated into centrosymmetrical dimers through short Au–Au contacts. Compound 5 forms one‐dimensional infinite chains through a similar aggregation via the two bifurcated sulfonium end groups of each individual dicationic unit. The dications of compound 6 are associated only into centrosymmetrical dimers leaving one of the two sulfonium groups of each unit without auriophilic contacts to neighbouring dications, probably owing to an internal Au–S contact with the thioether function.
Synthesis, Characterization and Polymerization Behavior of {(1R, S)‐2‐(η5‐9‐Fluorenyl)‐1‐[η5‐(1R,S)‐indenyl]‐1‐phenylethane}zirconium dichloride and {(1R,S)‐Cyclohexyl‐2‐(η5‐octahydro‐9‐fluorenyl)‐1[η5‐tetrahydro‐(1R,S)‐indenyl]ethane}zirconium Dichloride
Authors: Jany Gerhard , Repo Timo , Gustafsson Marina , Leskelä Markku , Polamo Mika , Klinga Martti , Dietrich Ulf , Rieger Bernhard
Published: July 2007

Epoxystyrene (1a) were converted into their corresponding alcohols, 2a–c, by treatment with either fluorenyl‐ or indenyllithium. These alcohols were then further converted into their trifluoromethanesulfonate derivatives, 3a–c. Subsequent reaction of the triflates with fluorenyl‐, indolyl‐, or tetraphenylcyclopentadienyllithium resulted in formation of 2‐(9‐fluorenyl)‐1(1‐indenyl)‐1‐phenylethane (4a), and 1‐(9‐fluorenyl)‐2‐(5‐tetraphenylcyclopentadienyl)ethane (4c). The ansa‐metallocene (1‐(R,S)‐2(η5‐9‐fluorenyl)‐1‐[η5‐1(R,S)‐indenyl]‐1‐phenylethane]ZrCl2 (5a) was prepared from the dilithio salt of 4a. Hydrogenation of 5a with H2/PtO2 leads to {1(R,s)‐cyclohexyl‐2‐(η5‐octahydro‐9‐fluorenyl)‐1‐[η5‐tetrahydro‐1(R,S)‐indenyl]ethane]ZrCl2 (6a. The complexes 5a and 6a were activated with methylalumoxane (MAO) and used for propene polymerization. The solid state structures of 4b, 4c, and 5a are reported.
Synthesis of a Bisdienophilic Phthalocyanine and of Precursors for Repetitive Diels‐Alder Reactions Based on Hemiporphyrazines and Phthalocyanines
Authors: Stihler Patrick , Hauschel Bernd , Hanack Michael
Published: July 2007

The specific synthesis of a metal‐free bisdienophilic phthalocyanine 193, suitable for repetitive Diels‐Alder reactions, is reported. This was achieved by condensation of 191,3,3‐trichloro‐6/7‐nitroioindolenine (191) and 4,9‐dibutoxy‐2,3,5,8‐tetrahydro‐1,3‐diimino‐1H‐5,8‐epoxybenz[f]isoindoline (2). The ability of 3 to undergo Diels‐Alder reactions was tested by reaction with an excess of 1,2,3,4‐tetraphenylcyclopentadienone (5). Experimental data of the hemiporphyrazines 9, 10, and 11, which can be used as precursors for the synthesis of ladder polymers, are also given in the Experimental Section.
1,3‐Di‐tert‐butyl‐2,2,4,4‐tetrahalocyclodisilazanes ‐ Synthesis, X‐ray Crystal and Gas‐Phase Structures
Authors: Brönneke Christiane , Herbst‐Irmer Regine , Klingebiel Uwe , Neugebauer Peter , Schäfer Martina , Oberhammer Heinz
Published: July 2007

The syntheses of 1,3‐di‐tert‐butyl‐2,2,4,4‐tetrachlorocyclodisilazane (3) and of di‐tert‐butyl‐2,2,4,4‐tetrafluorocyclodisilazane (4) are reported. The X‐ray crystal structure of 3 and the electron‐diffraction gas‐phase structure of 4 have been determined. Both cyclodisilazanes possess planar four‐membered rings and nearly planar configurations at the nitrogen atoms. The Si‐N bond lengths are 171.1(1) pm and 170.6(3) pm and the Si ⃛Si transannular distances 245.0(1) and 241.3(13) pm in 3 and 4, respectively.
Chiral Polysiloxane‐Fixed Metal 1,3‐Diketonates (Chirasil‐Metals) as Catalytic Lewis Acids for a Hetero Diels‐Alder Reaction ‐Inversion of Enantioselectivity Upon Catalyst ‐Polymer Binding
Authors: Keller Fritz , Weinmann Hilmar , Schurig Volker
Published: July 2007

A dimethylpolysiloxane chain is covalently bound to the monomeric Lewis acid catalyst (1R)‐(+)‐oxovanadium(1V) bis[3‐ heptafluorobutanoylcamphorate] [(+)‐5a] at the C‐10 position of the camphor moiety yielding the novel chiral polymeric (1S)‐( +)‐oxovanadium(1V) bis[3‐heptafluorobutanoylcamphorate] ‐dimethylpolysiloxane [( +)‐6a][1]. The Lewis acid promoted hetero Diels‐Alder reaction of trans‐l‐methoxy‐3‐(trimethylsilyloxy)‐ 1,3‐butadiene (1) and benzaldehyde (2) is studied in the presence of the enantiomerically pure monomeric (5a, 5b) and polymeric (6a, 6b) catalysts. The monomeric and polymeric catalysts of identical chirality[1] invoke opposite enantioselectivities toward the formation of 2‐phenyl‐ 2,3‐dihydro‐4H‐pyrone (4). This remarkable result is corroborated by numerous control experiments. Thus, it is demonstrated that the environment of the active site of the catalyst is changed when the complex is fixed to a polymeric chain. In contrast to 5 and 6, the monomeric 12 and polymeric 13 europium(III) tris[3‐heptafluorobutanoylcamphorates] of identical chirality invoke the same enantioselectivity toward the formation of 4. The concept of polymer attachment is utilized to recover the catalyst from the reaction mixture by precipitation and to recycle it for subsequent catalytic runs.
Preparation and Structures of Hexaphenyl‐ and Hexatolyltantalates(V)
Authors: Kleinhenz Sven , Schubert Mario , Seppelt Konard
Published: July 2007

By reacting TaCl5 with LiC6H5 and LiC6H4‐4‐CH3 salts, the anions Ta(C6H5)6 and Ta(C6H4‐4‐CH3)6 were obtained in small yields. They were structurally characterized by low‐temperature single‐crystal structure determination and found to have quite similar structures, which can be described as slightly distorted trigonal prismatic.
Reactive EC [p‐p] π Systems, 46 Syntheses and X‐ray Crystal‐Structure Analyses of Trifluoromethyl‐Substituted Ketiminodiselanes, Selenoamides and Selenoacrylamides
Authors: Blau Hanne , Grobe Joseph , Van Duc Le , Krebs Bernt , Läge Mechthild
Published: July 2007

Bis(trifluoromethylketiminoalkyl)diselanes [SeC(=NR)CF3]2 (6) [R = Me (a), iPr (b), tBu (c)] have been prepared in high yields (55‐70%) by reaction of the diselane (SeC2F5)2 (2) with RNH2. However, the analogous reaction of 2 with secondary amines, R2NH, results in the cleavage of the Se‐Se bond and leads to the N,N‐dialkyl‐2,2,2‐trifluoroselenoacetamides Se=C(NR2)CF3 (7) [R = Me (a), iPr (b)]. Cleavage of 6a‐6c with Me3SnH affords the selenoamides Se=C(NHR)CF3 (9) and the corresponding stannylselanes Me3SnSeC(=NR)CF3 (10) [R = Me(a), iPr (b), tBu (c)]. Selenoamides 7 and 9 can also be prepared from pentafluoroethylselenol HSeC2F5 (3), Se=C(F)CF3, (1) or its polymer [SeC(F)CF3]n (4) and primary or secondary amines. N,N‐dialkyl‐2‐methyl‐3‐fluoro‐4,4,4‐trifluoroselenoacrylamides Se=C(NR2)C(Me)=C(F)CF3[R = Et (13a), iPr (13b)] are prepared in moderate yields under mild conditions by treating either trifluoromethylselenocarbonyl fluoride (1) or its polymer [SeC(F)CF3]n with 1‐dialkylamino‐1‐propynes. The reaction proceeds by [2 + 2] cycloaddition and stereospecific electrocyclic ring‐opening, yielding, with respect to the resulting CC double bond, the E isomer as the only product. The molecular structures of 7b, 9a and 13b show the typical features of selenoamides with C(Se)‐N bond shortening and C‐Se bond elongation due to π interaction of the N lone pair with the CSe double bond. The observed perpendicular orientation of the selenoamide and the alkene units of 13b prevents π delocalization.
Synthesis and Structure of 2,2′ ‐Boryl‐, Germyl‐Silyl‐, and Stannyl‐Substituted 1,1′ ‐Binaphthyl Systems
Authors: Schilling Birgit , Kaufmann Dieter E. , Kaiser Volkier
Published: July 2007

A number of Lewis acid binaphthyl systems, substituted in 2‐or 2,2′‐position, are synthesized by lithiation of 2,2′‐dibromo‐1,l ′‐binaphthyl (5), followed by addition of various electrophiles. Stepwise lithiation and subsequent borylation with trimethyl borate leads to the bromoboronic acid 6, which can be stabilized by esterification with pinacol giving 7. By increasing the reaction mixture to 2 equiv. of n‐butyllithium and 2 equiv. of methyl borate the path to the binaphthylmonoboronic acid ester 9 is opened up. A further increase in the quantity of electrophile also leads to the binaphthylbisboronic acid ester 12. The 2,2′‐disubstituted silyl, germyl, and stannyl derivatives 13a‐15a are accessible in good yields. Treatment with boron halides leads exclusively to methyl/halogen exchange, giving the bidentate Lewis acids 13b‐15b, the former of which can be bridged by oxygen.Only in case of the bis(tributylstannyl)binaphthyl 16a does ipso substitution occur in the presence of boron trichloride, giving the bis(dichloroboryl)‐substituted binaphthyl 16b which can then be hydrolysed to 11. The structures of the majority of the compounds were investigated by X‐ray diffraction. In case of the 2,2′‐disubstituted compounds 13a‐15a the naphthyl groups are orientated perpendicular to each other. The intra‐ and intermolecular interactions are dominated by this binaphthyl system. In case of the oxygenbridged compounds 13c and 14c the angle between the naphthyl planes decreases to about 70°. This also has an effect on the packing of the molecule; in this instance the orientation of two naphthyl in neighbouring molecules is nearly parallel. The structure of the diboronic acid is dominated by intra‐ and intermolecular hydrogen bonding.
Benzophenoneimine Complexes of Copper(1)
Authors: Schneider Wolfgang , Bauer Andreas , Schmidbaur Hubert
Published: July 2007

The reactions of [(MeCN)4Cu]BF4 with two or three equivalents of benzophenoneimine lead to the formation of [(Ph2CNH)2]BF4 (1) and [ (Ph2CNH)3Cu]BF4 (2), respectively. A further equivalent of the ligand does not coordinate to the cation of complex 2. The crystal structures of both compounds were determined. 1 shows a linearly two‐coordinated copper(I) center with a Cu‐N distance of 1.877(2) Å. In compound 2 a distorted trigonal planar coordination of copper is observed with N‐Cu‐N angles of 114.5(2), 112.9(2) and 132.4(2)°, corresponding to two nearly equal Cu–N distances [Cu–N2 1.947(5) and Cu–N3 1.934(5) Å] dnd a significantly longer third one (Cu‐N1 2.011(5) Å]. A comparison of these data with recently determined structures of bis(benzophenoneimine)silver(I) and ‐gold(I) complexes shows that the covalent radii of the monovalent coinage metals decrease in the order Ag(I) > Au(I) > Cu(I).
Temperature‐dependent Ring‐Opening and ‐Closure of a Cyclic Phosphane‐Borane
Authors: Sigl Marcus , Schier  , Schmidbaur Hubert
Published: July 2007

A phosphane‐borane (3) with the P‐B bond integrated into a seven‐membered ring was prepared from 4‐pentenyl‐diphenylphosphane (4) by hydroboration using 9‐borabicyclononane (9‐BBN). The product was confirmed to have a ring structure in the solid state by single crystal X‐ray diffraction. The P‐B distance of 2.057(2) Å is indicative of a standard donor‐acceptor bond similar to the type found in homologous five‐ and six‐membered rings. The room‐temperature 31P‐NMR signal of the compound in various solvents (δ ≈ ‐ 15) is not compatible with the cyclic structure and suggests that ring opening occurs as the compound is dissolved. Variable‐temperature NMR work corroborated this assumption, and the enthalpy of ring closure was determined to be ΔH = ‐30.5(4) kJmol‐l. In CD2C12 at ‐90°C, δ31P is shifted to +3.5 ppm to low field, suggesting virtually complete ring closure under these conditions.
Flash Pyrolysis of 1,1,1‐Trimethyltetrasilane ‐ Evidence for the Formation of Dibridged Si2H2
Authors: Maier Günther , Reisenauer Hans Peter , Meudt Andreas , Egenolf Heiko
Published: July 2007

Pulsed flash pyrolysis of 1,1,l‐trimethyltetrasilane (5) led to trimethylsilane, silane and a further species which is believed to be dibridged Si2H2 (13). Another route to 13 was found in the cocondensation of hydrogen and silicon atoms in an argon matrix at 12 K. The identification of matrix‐isolated 13 is based on observed IR bands at 1475.6, 1092.8 and 890.3 cm−1. These positions are in good agreement with the ab initio calculated wavenumbers for the strongest absorptions of 13. The band shifts for the mono‐ and dideuterated isotopomers support this assignment.
Synthesis and Structures of Bis(tetramethylipiperidino)aluminum Halides‐X‐ray Crystal Structures of tmp2AlX (X = Cl, Br, I) and [tmp2A1(μ‐F)l2
Authors: Krossing Ingo , Nöth Heinrich , Tacke Christiane , Schmidt Martin , Schwenk Holger
Published: July 2007

N‐Lithio‐2,2,6,6‐tetramethylpiperidine [Li(tmp)] reacts with AlX3 (X = Cl, Br) in diethyl ether/ n‐hexane solution to generate the products of substitution and ether cleavage, [tmpAl(X)(μ‐OEt)], (la, X = Cl; 1b, X = Br). However, when the reaction is allowed to proceed in n‐hexane alone, an almost quantitative yield of compounds tmp2AlX (2a, X = Cl; 2b, X = Br; 2c, X = I) is obtained. According to 27AI‐NMR spectroscopy, mass spectroscopy, cryoscopy, and X‐ray crystal structure determinations, these compounds are monomeric in the solid state, in solution, and in the gas phase. 2b reacts with AgBF4 yielding the fluoride‐bridged dimer (tmp2AlF), 2d, as shown by X‐ray crystal structure determination.
The Role of the 2,4,6‐Tris(trifluoromethyl)phenylamino Group in Stabilizing New Phosphorus‐, Arsenic‐, and Germanium‐Containing Main‐Group Compounds and Transition‐Metal Derivatives
Authors: Ahlemann Jens‐T. , Roesky Herbert W. , Murugavel Ramaswamy , Parisini Emilio , Noltemeyer Mathias , Schmidt Hans‐G. , Müller Olaf , Herbst‐Irmer Regine , Markovskii Leonid N. , Shermilovich Yuri G.
Published: July 2007

The reactions of potassium Rf‐amide [Rf = tris(trifluoromethyl)phenyl](2) with PCl3, AsC13, and GeC12 · dioxane yield new four‐membered inorganic heterocycles [RfNPCl]2 (3), [RfNAsC1]2 (4), and [RfNGe]2 (5), respectively. On the other hand, the reaction of Rf‐amide 2 with two equivalents of RfPCl2 leads to the formation of the imino‐γ3‐phosphane RfN=PRf (6) and the diamino‐γ3‐phosphane (RfNH)2PRf (7). The iminophosphane 6 reacts with Ni(CO)2(PPh3)2 and forms the complex [Ni(PPh3)2(RfN=PRf)] (9), in which the imino‐ phosphane coordinates to the metal through the phosphorus lone pair. Treatment of lithium amide 2 with transition metal chlorides ZnCl2 and FeCl2 yields the imido/amido spirocyclic metal derivatives 9 and 10, respectively. Compounds 3–10 have been extensively characterized by their analytical and mass, IR, and NMR (1H, 19F, and 31P) spectroscopy. Further, the molecular structures of all the compounds have been unambiguously determined by single‐crystal X‐ray diffraction studies. The diazadigermetidine 5 crystallizes in a fluorescent‐yellow orthorhombic and a yellow monoclinic crystal modification. The results obtained reveal the role of Rf, group in stabilizing new multiple bonded systems and inorganic heterocycles. A skeletal rearrangment of the Rf ligand is observed in the reactions leading to compounds 9 and 10. Moreover, the preparation of compounds 9 and 10 indicates the limitation of the use of this ligand in the preparation of new metal‐amide systems, especially where the metal atoms have a strong tendency for the formation of strong MF bonds.