186,280 research outputs found
12-Vertex Zwitterionic Bis-phosphonium-nido-carborates through Ring-Opening Reactions of 1,2-Diphosphetanes
No full textCarborane-substituted 1,2-diphosphetanes (Ia,b) react with elemental lithium in THF with cleavage of the P−P bond to give a deep red solution from which, in the case of Ia, red crystals of a lithiated intermediate, [{1-Li(THF)PtBu-6-PtBu-4,1,6-closo-Li(THF)C2B10H10}{Li(THF)3}]2⋅2 THF (2 a), are obtained. The compound is dimeric, C2-symmetric and contains six lithium and four phosphorus atoms. Two lithium atoms cap the six-membered C2B4 faces, resulting in two 13-vertex closo-clusters (according to Wade's rules) with docosahedral geometry. The addition of methyl iodide resulted in the formation of zwitterionic bis-phosphonium-nido-carborates 7,10-bis(tert-butyldimethylphosphonium)dodecahydro-7,10-dicarba-nido-dodecaborate(2−) (1 a) and 7,10-bis(N,N-diisopropylaminodimethylphosphonium)dodecahydro-7,10-dicarba-nido-dodecaborate(2−) (1 b) in moderate to good yields. Compounds 1 a and 1 b exhibit short Ccluster−P bonds and large Ccluster⋅⋅⋅Ccluster distances in the solid state. Further insight into the ring opening and reduction potential of the alkyl halide was obtained from methylation reactions of different 1,2-bis-phosphinocarboranes. The reaction of rac-/meso-1,2-bis(tert-butylmethylphosphino)-1,2-dicarba-closo-dodecaborane(12) (3 a) with two equivalents of methyl iodide also resulted in the formation of 1 a (as shown by NMR spectroscopy), whereas the reaction of 1,2-bis(diphenylphosphino)-1,2-dicarba-closo-dodecaborane(12) with methyl triflate afforded the phosphonium salt 1-methyl-diphenylphosphonium-2-diphenylphosphino-1,2-dicarba-closo-dodecaborane(12) triflate (4) without reduction of the cluster
Oxidative P−P Bond Addition to Cobalt(−I): Formation of a Low-Spin Cobalt(III) Phosphanido Complex
No full textThe first homoleptic cobalt phosphanido complex [K(thf)(4)][Co{1,2-(PtBu2)(2)C2B10H12}(2)] (1) was prepared by an unprecedented oxidative P-P bond addition of an ortho-carborane-substituted 1,2-diphosphetane to cobalt(-I) in [K(thf)(0.2)][Co((4)-cod)(2))] (cod=1,5-cycloctadiene). Compound 1 is a rare distorted tetrahedral 3d(6) complex with a low-spin ground state configuration. Magnetic measurements revealed that the complex is diamagnetic between 2 to 270K in the solid state and at 298K in [D-8]THF solution. Based on DFT calculations, the unusual singlet ground state is caused by the strong sigma-donor and moderate -donor properties of the bis(phosphanido) ligand
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
CCDC 1988439: Experimental Crystal Structure Determination
No full textXUXGUV : diiodo-(1,2,4-triphenyl-6-(pyridin-2-yl)-1,4-dihydrophosphinin-4-yl radical)-nickel(ii) toluene solvate Space Group: P 1 (2), Cell: a 9.0557(2)Å b 13.2167(3)Å c 13.9415(4)Å, α 104.895(2)° β 96.912(2)° γ 101.037(2)° Related Article: J. Leitl, P. Coburger, D. J. Scott, C. G. P. Ziegler, G. Hierlmeier, R. Wolf, N. P. van Leest, B. de Bruin, G. Hörner, C. Müller|2020|Inorg.Chem.|59|9951|doi:10.1021/acs.inorgchem.0c0111
Evaluation of a Navigated 3D Ultrasound Integration for Brain Tumor Surgery: First Results of an Ongoing Prospective Study
No full textThe aim of the study was to assess the quality, accuracy and benefit of navigated 2D and 3D ultrasound for intra-axial tumor surgery in a prospective study. Patients intended for gross total resection were consecutively enrolled. Intraoperatively, a 2D and 3D iUS-based resection was performed. During surgery, the image quality, clinical benefit and navigation accuracy were recorded based on a standardized protocol using Likert’s scales. A total of 16 consecutive patients were included. Mean ratings of image quality in 2D iUS were significantly higher than in 3D iUS (p 0.46). The benefit was rated 2.2 in 2D iUS and 2.6 in 3D iUS (p = 0.08). The benefit remained stable in 2D, while there was a slight decrease in the benefit in 3D after complete tumor resection (p = 0.09). The accuracy was similar in both (mean 2.2 p = 0.88). Seven patients had a small tumor remnant in intraoperative MRT (mean 0.98 cm3) that was not appreciated with iUS. Crucially, 3D iUS allows for an accurate intraoperative update of imaging with slightly lower image quality than 2D iUS. Our preliminary data suggest that the benefit and accuracy of 2D and 3D iUS navigation do not undergo significant variations during tumor resection
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
CCDC 1988434: Experimental Crystal Structure Determination
No full textXUXFUU : bis(2-(4,6-diphenylphosphinin-2-yl)pyridine)-nickel(i) tetrafluoroborate toluene solvate Space Group: P 1 (2), Cell: a 10.2588(3)Å b 15.4329(5)Å c 15.5298(6)Å, α 115.755(3)° β 103.667(3)° γ 96.193(2)° Related Article: J. Leitl, P. Coburger, D. J. Scott, C. G. P. Ziegler, G. Hierlmeier, R. Wolf, N. P. van Leest, B. de Bruin, G. Hörner, C. Müller|2020|Inorg.Chem.|59|9951|doi:10.1021/acs.inorgchem.0c0111
CCDC 1988437: Experimental Crystal Structure Determination
No full textXUXGIJ : 2-(1,1,4,6-tetraphenylphosphinin-2-yl)pyridine Space Group: P 1 (2), Cell: a 10.2550(4)Å b 10.4958(5)Å c 12.4245(5)Å, α 101.719(4)° β 97.635(4)° γ 102.229(4)° Related Article: J. Leitl, P. Coburger, D. J. Scott, C. G. P. Ziegler, G. Hierlmeier, R. Wolf, N. P. van Leest, B. de Bruin, G. Hörner, C. Müller|2020|Inorg.Chem.|59|9951|doi:10.1021/acs.inorgchem.0c0111
CCDC 2007973: Experimental Crystal Structure Determination
No full textXUXKIN : bis(2-(4,6-diphenylphosphinin-2-yl)pyridine)-nickel(0) Space Group: P 1 (2), Cell: a 10.3385(6)Å b 11.0440(7)Å c 15.6774(9)Å, α 97.288(5)° β 92.321(5)° γ 107.857(5)° Related Article: J. Leitl, P. Coburger, D. J. Scott, C. G. P. Ziegler, G. Hierlmeier, R. Wolf, N. P. van Leest, B. de Bruin, G. Hörner, C. Müller|2020|Inorg.Chem.|59|9951|doi:10.1021/acs.inorgchem.0c0111
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