11,094 research outputs found
Preparation and Chemical Reactions of Ruthenium Cp Phosphine Complexes with 1,6-Endiyne.
No full text利用五種含有末端丙炔醇和以三甲基矽保護的末端炔相連結的1,6-雙炔化合物與氯配位釕金屬之三苯基磷化合物[Ru]-Cl ([Ru] = Cp(PPh3)2Ru)可以生成兩種不同形式的錯合物。在第一種形式,釕金屬化合物只與末端丙炔醇進行反應可以生成釕金屬亞乙烯基錯合物，釕金屬亞丙烯基錯合物，與釕金屬炔基錯合物。在第二種形式的產物中，1,6-雙炔化合物中有一碳碳鍵的生成可得到釕金屬丙烯基碳烯錯合物。化合物1與氯配位釕金之三苯基磷化合物反應會得到第一種形式的混合產物，分別為釕金屬亞丙烯基錯合物8與磷基加成之釕金屬炔基錯合物9，後者為一個三苯基磷加成雙炔配位基的三號位置碳上。加入過量的三苯基磷於反應中即可以得到單一錯合物9。然而，在1,6雙炔化合物中引入一個甲基取代於1,6-雙炔化合物三號碳位置與氯配位釕金屬之三苯基磷化合物反應會得到同樣有磷基加成在配位基上的釕金屬丙烯基碳烯錯合物11。這反應包含了兩個炔基同時配位在金屬上進行環化反應，同時伴隨著三苯基磷的遷移至1,6-雙炔配位基的一號位置碳上。在這兩種反應中，可以觀察到炔基對三苯基磷有很強的結合力，使得碳磷鍵的生成有不同的位向選擇性。利用鹽酸與五個電子配位的釕金屬丙烯基碳烯錯合物11反應可以得到高產率含有四個電子配位的1,3-丁二烯基與氯配位的金屬錯合物12。含有正丁基取代在丙烯醇的雙炔化合物3與釕金屬錯合物反應，可以同時獲得釕金屬亞丙烯基錯合物13與釕金屬丙烯基錯合物14。而利用化合物7與含氯取代的釕金屬錯合物反應則可同時獲得釕金屬亞乙烯基錯合物16與釕金屬丙烯基錯合物17。五個錯合物9，11，12，13，16的結構鑑定可以藉由X光繞射分析確定。
另外我們又研究了一系列釕金屬炔基化合物環化反應。這一系列的釕金屬炔基化合物可以由釕金屬亞丙烯基錯合物或者磷基加成在配位基上的釕金屬炔基錯合物製備而成。在鹼性條件下我們可以利用不同的醇類或者利用四丁基氟化銨在四氫呋喃溶液下將末端炔進行去保護反應得到一系列的烷氧基加成在雙炔配位基三號位置的釕金屬炔基化合物。對錯合物19進行質子化反應，可以得到釕金屬亞乙烯基錯合物混合產物20和20`，這兩個金屬錯合物可能是經由釕金屬炔基π-配位錯合物隨後發生氫和金屬的遷移。對錯合物21a - d而言，有一個碳碳鍵生成的環化反應發生在β碳和末端炔基上而形成一個六員環的釕金屬亞乙烯基錯合物。這個反應可能是經由6-endo-dig的反應途徑。這些環化的釕金屬亞乙烯基錯合物22a - d在與酸性媒介反應可以生成釕金屬烷氧基碳烯錯合物25a及25b，或者釕金屬醯基錯合物26，並且結構中都含有一個萘圓環。這樣的1,3-烷氧基的遷移可能是經由中間物金屬碳炔化合物而得到。不同於金屬炔基錯合物19，錯合物4N擁有一個缺電子的吡啶芳香環，並且能夠與鹽類六氟磷酸鉀與氯仿反應生成環化的亞乙烯基錯合物5N。這些所有的環化亞乙烯基錯合的結構是由核磁共振光譜分析鑑定，而金屬醯基錯合物則是利用X光單晶繞射鑑定結構。Reactions of five 1,6-diynes 1, 1N, 2, 3 and 7, each with one terminal propargylic alcohol and one internal triple bond containing Me3Si groups, with [Ru]-Cl ([Ru] = Cp(PPh3)2Ru) led to two types of products. In the first type, only the propargylic group involves in the reaction leading to vinylidene, allenylidene or acetylide complexes. A C-C bond formation of two triple bonds in 1,6-diynes gave allylcarbene products of the second type. The reaction of 1 with [Ru]-Cl yielded only the first type, giving a mixture of two cationic complexes; the allenylidene complex 8 and the phosphonium acetylide complex 9, the latter resulting from further addition of a phosphine molecule to Cγ of 8. The same reaction in the presence of excess phosphine gave 9 only. However, with an additional methyl group, the 1,6-diyne 2 reacted with [Ru]-Cl to give the allylcarbene complex 11 also with a phosphonium group on the ligand. The reaction proceeds by a cyclization reaction involving two triple bonds on the metal accompanied with a migration of a phosphine ligand to Cα. In both reactions strong affinity between alkyne and phosphine was observed resulting in formations of P-C bonds in different regioselectivity. Addition of HCl to 11 transforms the five-electron donor allylcarbene ligand to the four-electron donor diene ligand along with formation of a Ru-Cl bond giving complex 12 in high yield. From the reaction of [Ru]-Cl with diyne 3 containing a t-butyl group at the propargylic carbon, both the allenylidene complex 13 and the allylcarbene complex 14 were obtained. The reaction of diyne 7 with [Ru]-Cl also gave both types of complexes, namely the vinylidene complex 16 and the allylcarbene complex 17. Crystal structures of complexes 9, 11, 12, 13, and 16 are determined by single crystal X-ray diffraction analysis.
We also studied the cyclic reaction of a series of the acetylide complexes. These acetylide complexes were prepared from the allenylidene or phosphonium acetylide complexes which using the Cp(PPh3)2RuCl and 1,6-diyne-4-ene-3-ol connected with an aromatic group in presence of KPF6 in CH2Cl2. Deprotection of the terminal alkyne were carried out in different alcohol solution under basic condition or TBAF in THF solution gave a series of acetylide complexes with terminal alkyne group. For 19, protonation of acetylide complex can lead two vinylidene complexes 20 and 20’ which possibly via a π-coordinated alkynyl complex followed by hydrogen and metal migration. For 21a - d, a C-C bond-forming cyclization reaction is occurred at Cβ and the terminal alkyne to generate a six-member ring in the vinylidene complex. The reaction may undergo a 6-endo-dig reaction pathway. These cyclic vinylidene complexes 22a - d under acidic-medium condition could form the alkoxy carbene 25a - b or acyl complexe 26 which with a naphathyl ring in the structure. This 1,3-alkoxy migration might via metal carbene complex as an intermediate. For 4N, that the difference to the acetylide complex 19 is containing an electrophilic pyridinyl ring, it could form the cyclic vinylidene complex 5N in presence of KPF6 in CHCl3. All structures determinations of the cyclic vinylidene complexes are using NMR spectra analysis and the acyl complex is using the single crystal X-ray diffraction analysis
Ma Huan (original author), Wan Ming (ed.) Ming chaoben " Yingya shenglan " jiaozh
No full textPtak Roderich. Ma Huan (original author), Wan Ming (ed.) Ming chaoben " Yingya shenglan " jiaozh. In: Archipel, volume 71, 2006. Autour de la peinture à Java. Volume II. pp. 240-244
FIGURE 1 in Vincetoxicum (Apocynaceae: Asclepiadoideae) in Taiwan: Two new combinations and a new record
No full textFIGURE 1. Vincetoxicum in Taiwan. A. V. atratum. B. V. brownii. C. V. chinense. D. V. fordii. E. V. hirsutum. F. V. insulicola. G. V. lui. H. V. oshimae. I. V. sui. J. V. taiwanense. Photographers. A, C, H, I & J, Shih-Wen Chung. B, D & E, Tian-Chuan Hsu. F, Ming-Yu Kuo. G. Po-Hao Chen.Published as part of Hsu, Tian-Chuan, Huang, Wei-Jie & Chung, Shih-Wen, 2021, Vincetoxicum (Apocynaceae: Asclepiadoideae) in Taiwan: Two new combinations and a new record, pp. 287-290 in Phytotaxa 478 (2) on page 288, DOI: 10.11646/phytotaxa.478.2.11, http://zenodo.org/record/541312
Sedum triangulisepalum T. S. Liu & N. J. Chung ex T. C. Hsu & S. W. Chung 2022, sp. nov.
No full text<p> <i>Sedum triangulisepalum</i> T.S. Liu & N.J. Chung ex T.C. Hsu & S.W. Chung, <i>sp. nov.</i></p> <p> [“ <i>Sedum triangulisepalum</i> T.S. Liu & N.J. Chung (1977: 21, as <i>triangulosepalum</i>)”, <i>nom. inval.</i>; “ <i>Sedum triangulisepalum</i> T.S. Liu & N.J. Chung ex H.W. Lin (1999: 102, as <i>triangulosepalum</i>)”, <i>nom. inval.</i>; “ <i>Sedum triangulisepalum</i> T.S. Liu & N.J. Chung ex S.W. Chung ” in Chen <i>et al.</i> (2017: 329, as <i>triangulosepalum</i>), <i>nom. inval.</i>].</p> <p> <b>Type:</b> — TAIWAN. Hualien County: Hsiulin Township, Lo-ma-wan Shan, 1800 m elev., 15 June 1973, <i>N.J. Chung 280</i> (holotype: NTUF!, barcode: F00008307; isotypes: NTUF!, eight sheets, barcodes: F00008308–F00008315).</p> <p> <b>Diagnosis:</b> — <i>Sedum triangulisepalum</i> is similar to <i>S. truncatistigmum</i> T.S. Liu & N.J. Chung (1977: 23) in sharing epiphytic life-form, alternate and ±flattened leaves and fused calyx, while the former is readily distinguished in having longer calyx (1.5–2.0 vs. 0.8–1.0 mm) that are only fused at the base (vs. nearly entirely fused).</p> <p> <b>Morphological descriptions and illustrations:</b> —This species has been described by Liu & Chung (1977: 21) and illustrated by Tang & Huang (1989: 27, pl. 15, as <i>Sedum microsepalum</i>), Chen <i>et al.</i> (2017: 329) and Ito <i>et al.</i> (2017: 11, fig. 1D).</p> <p> <b>Distribution and ecology:</b> — <i>Sedum triangulisepalum</i> is endemic in Taiwan, where it occurs in the northern and eastern portions of the main island and usually grows on tree trunks in montane cloud forests at 500–2000 m elev. (Liu & Chung 1977; Chen <i>et al.</i> 2017; Ito <i>et al.</i> 2017).</p> <p> <b>Etymology:</b> —The specific epithet is composed of two Latin elements: <i>triangulus</i>, triangular, and <i>sepalum</i>, sepal, referring to its triangular calyx lobes. It should be spelt as “ <i>triangulisepalum</i> ” instead of “ <i>triangulosepalum</i> ” as originally published by Liu & Chung (1977) according to Art. 60.10 of the ICN.</p> <p> <b>Note:</b> —Two gatherings, “ <i>Suzuki s.n.</i> ” collected from Wulai and “ <i>Chuang 280</i> ” collected from Lomawanshan, were cited under <i>Sedum triangulisepalum</i> by Liu & Chung (1977), and “ <i>Chuang 280</i> ” is presumably a typo of “ <i>Chung 280</i> ” since the “ <i>N.J. Chung 280</i> ” gathering, collected by the second original author and currently preserved in NTUF, matches well with the data given in the original publication (Liu & Chung 1977). There are nine duplicates of <i>Chung 280</i>, including one (barcode: F00008307) labelled as “ holotype ” and the others (barcodes: F00008308–F00008315) as “isotype”. Although these labels could not be archived as the legitimate designation of types as they are not effectively published (see Art. 7.10 of the ICN), they supposedly reflect the original author’s intention and are thus adopted here. Images of all type materials are available in the “Plants of Taiwan ” database [http://tai2.ntu.edu.tw].</p>Published as part of <i>Hsu, Tian-Chuan & Chung, Shih-Wen, 2022, Validation of the name Sedum triangulosepalum (Crassulaceae), pp. 215-216 in Phytotaxa 547 (2)</i> on page 215, DOI: 10.11646/phytotaxa.547.2.10, <a href="http://zenodo.org/record/6571375">http://zenodo.org/record/6571375</a>
The politics of fashion: perceptions of power in female clothing and ornamentation as reflected in the sixteenth-century Chinese novel Jin Ping Mei
Full text linkThis thesis examines issues of female power and influence in sixteenth-century China focusing on how women and their roles were perceived in the changing social environment of the mid-late Ming dynasty. Using aspects of a New Historicist approach, information from contemporary literary and historical sources are analysed alongside each other. With its emphasis on the lives of women and preoccupation with the description of material objects, the late Ming novel Jin Ping Mei forms an important element in the thesis. China in the sixteenth century saw expanding urbanisation, the emergence of a new wealthy merchant class, increasing visibility of women and a questioning of traditional morality. Fashion consciousness, as one of the most conspicuous aspects of the new material culture, is a possible indicator of these trends. Traditional Western theories contend that fashion began in the particular context of Renaissance Europe. However, this study argues that a similar fashion awareness existed in China too, and was manifested in a competitive striving for social status, in this case specifically among women. In contrast to previous studies which downplayed the impact women had on defining traditional Chinese culture, this thesis demonstrates how women and their sartorial choices began to redefine the boundaries of material culture, influencing literati discourse which, in turn, re- influenced female behaviour
Portraits of Chung-Feng Ming-Pen with Autograph Inscription
Full text linkA number of portraits of Ch'an priests painted in Sung and Yüan Period China remain in Japan and they have often been discussed in the context of their influence to Japanese portraiture. Partly due to their impressiveness, they have tended to be regarded all homogeneous.
The present author intends to elucidate diverse aspects of Chinese Ch'an portraiture of the time through the comparison between those with his autograph inscription and those without among the portraits of Chung-fêng Ming-pêng, a high Ch'an priest in the Yüan Period.
1) His portraits can be largely divided into two types, that is, the humble figure with rough hair and the figure in dignity with the head shaved. They correspond to the contrasting phases of his life whose shift took place in the fifth year of Yen-yu Era(1318). The former is the figure as a hermit who wandered around from place to place and the latter is the figure as a monk of a temple which was recognized to be equivalent to the state temples after the emperor came to have a high regard for him.
2) The iconographical common feature that he lacks the little finger of the left hand is based on the affair that he burnt the finger when he entered priesthood under K'ao-fêng Yüan-miao.
3) Whereas his portraits with autograph inscription are faithful to actuality, the influence of arhat paintings and Bodhidarma paintings is detectable. Such a double image is not merely an artistic creation of the painters but a reflection of the inclination of his contemporary followers to recognize him to be an entity close to Buddhahood. The lack of the burnt finger, therefore, is not a simple physical characteristic but is an implication of high enlightenment.
4) Judging from the common iconography shared by numerous works, the uniformity of the size of the face, and from records concerning his selfinscribed portraits, it is presumable that there was some kind of organ in charge of his self-inscribed portraits. If that is correct, I-an who painted the one owned by the Kōgenji must have been closely associated with that organ and it is likely that the organ provided the Buddhist painters with the iconography appropriate to each self-inscribed portrait.journal articl
Concentration in Knowledge Output: A case of Economics Journals
Full text linkThis paper assesses the degree of author concentration in seven economics journals, which were published in India during 1990-2002. To measure the degree of author concentration, Lotka's Law was used. Moreover, we also make an exploratory analysis of the geographic, economics subfield and institutional concentration in 704 economics journals. An important finding of this paper is that specialized journals in the sample report the highest degree of author concentration. This result is quite similar to the findings by Cox and Chung (1991). Furthermore, there are several instances showing that the journals lean towards certain norms; this may affect the flow of innovative ideas into economics. We conclude that a knowledge activity, involving the high degree of concentration and a biased publication process, may affect the flow of new ideas into the discipline.Concentration, Lotka's Law
Tu Fu, Yuan Chieh, and the Poets of the Ch'ieh-chung-chi
No full textThe sudden upsurge of poetic spirit was a major factor in the flowering of poetry that marked the height of the T'ang. Among the men who, in the name of traditionalism, worked to encourage this revival of the poetic spirit, one of the most influential was Tu Fu's friend Su Yüan-ming 蘇源明 (d. 764). During the latter years of his stay in Ch'ang-an (754-758), Tu Fu became associated with Su Yüan-ming's traditionalist group, and was greatly influenced by them. Among the members of the group were Yüan Chieh 元結 (719-772) and the other poets represented in the anthology which Yüan Chieh compiled, entitled Ch'ieh-chung chi 篋中集. Yüan Chieh in particular enjoyed a close friendship with Su Yüan-ming. Tu Fu seems to have had no direct association with Yüan Chieh, but he was friendly with four of the Ch'ieh-chung-chi poets. The present paper discusses the connections between Yüan Chieh's associates and Tu Fu, and attempts to determine what influence they had on Tu Fu's work. The author has concentrated particularly upon the possible connections between Tu Fu's "San li" 三吏 "San pieh" 三別 and the twelve poems in Yüan Chieh's "Hsi-yüeh-fu" 系樂府. Among the latter, that entitled "Ch'ung-ling hsing" 春陵行 appears to have had a very significant influence on Tu Fu's late works
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