共查询到20条相似文献,搜索用时 15 毫秒
1.
New mixed metal complexes SrCu 2(O 2CR) 3(bdmap) 3 (R = CF 3 (1a), CH 3 (1b)) and a new dinuclear bismuth complex Bi 2(O 2CCH 3) 4(bdmap) 2(H 2O) (2) have been synthesized. Their crystal structures have been determined by single-crystal X-ray diffraction analyses. Thermal decomposition behaviors of these complexes have been examined by TGA and X-ray powder diffraction analyses. While compound 1a decomposes to SrF 2 and CuO at about 380°C, compound 1b decomposes to the corresponding oxides above 800°C. Compound 2 decomposes cleanly to Bi 2O 3 at 330°C. The magnetism of 1a was examined by the measurement of susceptibility from 5–300 K. Theoretical fitting for the susceptibility data revealed that 1a is an antiferromagnetically coupled system with g = 2.012(7), −2 J = 34.0(8) cm −1. Crystal data for 1a: C 27H 51N 6O 9F 9Cu 2Sr/THF, monoclinic space group P2 1/ m, A = 10.708(6), B = 15.20(1), C = 15.404(7) Å, β = 107.94(4)°, V = 2386(2) Å 3, Z = 2; for 1b: C 27H 60N 6O 9Cu 2Sr/THF, orthorhombic space group Pbcn, A = 19.164(9), B = 26.829(8), C = 17.240(9) Å, V = 8864(5) Å 3, Z = 8; for 2: C 22H 48O 11N 4Bi 2, monoclinic space group P2 1/ c, A = 17.614(9), B = 10.741(3), C = 18.910(7) Å, β = 109.99(3)°, V = 3362(2) Å 3, Z = 4. 相似文献
2.
The hydrothermal reactions of (Ph 4P)[VO 2Cl 2] and H 2C 2O 4 at 150 and 125°C yield (Ph 4P) 2[V 2O 2(H 2O) 2(C 2O 4) 3]·4H 2O (1) and (Ph 4P)[VOCl(C 2O 4)] (2), respectively. The structure of the molecular anion of 1 consists of a binuclear unit of oxovanadium(IV) octahedra bridged by a bisbidentate oxalate group. The VO 6 coordination geometry at each vanadium site is defined by a terminal oxo group, an aquo ligand, and four oxygen donors — two from the bisbidentate bridging oxalate and two from the terminal bidentate oxalate. The structure of 2 consists of discrete Ph 4P + cations occupying regions between [VOCl(C 2O 4)] −∞ spiral chains. The structure of the one-dimensional anionic chain exhibits V(IV) octahedra bridged by bisbidentate oxalate groups. Crystal data: 1·4H 2O, monoclinic P2 1/ n, A = 12.694(3), B = 12.531(3), C = 17.17(3) Å, β = 106.32(2)°, V = 2621.3(13) Å 3, Z = 2, Dcalc = 1.501 g cm −3, structure solution and refinement converged at a conventional residual of 0.0518; 2, tetragonal P4 3, A = 12.145(2), C = 15.991(3) Å, V = 2358.7(12) Å 3, Z = 4, R = 0.0452. 相似文献
3.
蛹虫草规模化栽培过程中,真菌病害普遍发生且危害严重。本研究对人工栽培蛹虫草中真菌病害进行调研,对病原真菌进行分离、纯化、鉴定及致病性检验,并分析病害发生的特点。结果发现引起蛹虫草病害的病原真菌主要有虫草生齿梗孢、产扁虫菌素单端孢、镰刀菌、裂褶菌、哈茨木霉、淡紫拟青霉、稻绿核菌、粉红枝穗霉、卵孢单端孢、扩展青霉、黄曲霉和黑曲霉。其中虫草生齿梗孢为引起蛹虫草侵染性病害的主要病原真菌。虫草生齿梗孢、产扁虫菌素单端孢、镰刀菌、裂褶菌和哈茨木霉主要为害蛹虫草子实体;淡紫拟青霉、稻绿核菌、粉红枝穗霉、卵孢单端孢、扩展青霉、黄曲霉和黑曲霉主要为害栽培料与蛹虫草菌丝体。镰刀菌、裂褶菌、哈茨木霉、淡紫拟青霉、稻绿核菌和粉红枝穗霉为引起蛹虫草病害的首次报道。本研究为蛹虫草病害防控奠定基础,以促进产业健康发展。 相似文献
4.
Warming responses of photosynthesis and its temperature dependence in two C 3 grass ( Agropyron cristatum, Stipa krylovii), one C 4 grass ( Pennisetum centrasiaticum), and two C 3 forb ( Artemisia capillaris, Potentilla acaulis) species in a temperate steppe of northern China were investigated in a field experiment. Experimental warming with infrared heater significantly increased daily mean assimilation rate ( A) in P. centrasiaticum and A. capillaris by 30 and 43%, respectively, but had no effects on other three species. Seasonal mean A was 13, 15, and 19% higher in the warmed than control plants for P. centrasiaticum, A. capillaries, and S. krylovii, respectively. The mean assimilation rate in A. cristatum and P. acaulis was not impacted by experimental warming. All the five species showed photosynthetic acclimation to temperature. The optimum temperature for photosynthesis ( Topt) and the assimilation rate at Topt in the five species increased by 0.33–0.78 °C and 4–27%, respectively, under experimental warming. Elevated temperature tended to increase the maximum rate of ribulose-1,5-bisphosphate (RuBP) carboxylation ( Vcmax) and the RuBP regeneration capacity ( Jmax) in the C 3 plants and carboxylation efficiency and the CO 2-saturated photosynthetic rate in the C 4 plant at higher leaf temperature, as well as the optimum temperatures for the four parameters. Our results indicated that photosynthetic responses to warming were species-specific and that most of the species in the temperate steppe of northern China could acclimate to a warmer environment. The changes in the temperature dependence of Vcmax and Jmax, as well as the balance of these two processes altered the temperature dependence of photosynthesis under climatic warming. 相似文献
5.
The reaction of dilithiated o-carborane ( closo-1,2-Li 2-1,2-C 2B 10H 10) with CuCl 2 gives 1,1′-bis( o-carborane) (1), 1,3′-bis( o-carborane) (2) and 1,4′-bis( o-carborane) (3). Compound 2 (C 4B 20H 22) crystallizes in the monoclinic space group P2 1/ n with A = 6.9275(6), B = 9.7655(8), C = 12.356(1) Å, β = 90.028(2)° and Z = 2. The structure was solved by direct methods and refined to R = 0.048 and Rw = 0.074. Compound 3 (C 4B 20H 22) crystallizes in the orthorhombic space group P2 12 12 1 with A = 6.8854(5), B = 12.523(1), C = 19.847(1) Å and Z = 4. The structure was solved by direct methods and refined to R = 0.078 and Rw = 0.091. The coupling reaction of dilithiated m-carborane ( closo-1,7-Li 2-1,7-C 2B 10H 10) with CuCl 2 results in the formation of 1,1′-bis( m-carborane) (4) and tetra( m-carborane) (5). 相似文献
6.
1. 1.|The germination of tomato “C38” seeds exposed to periodical white incandescent light occurs from 6.0° ± 0.2°C to 37.5° ± 0.2°C, being rate-limited for 10.3° T 25.9°C, and elsewhere limited by the germination capacity. 2. 2.|Rate averages are linearly T-dependent outside their optimum range (25.9° T 29.5°C) and rate variances are typically heterogeneous. 3. 3.|The smooth curvilinear Arrhenius plot indicates that diffusion processes cannot be rate-limiting outside the interval 25.9° T 29.5°C, whereas phase transitions and (or) transconformation of proteins may limit the rate above 34.9°C and, by opposite effects, below 15.3°C. 4. 4.|The thermal communication between the environment and the germinating seed proceeds by a temperature signal which is quenched by random thermal noise at T 11.2°C and at T 34.0°C.
Author Keywords: Temperature dependence of germination; Arrhenius plot of germination; germination rate; germination capacity; cynchronization of germination; temperature signal in germination; diffusion in germination; thermodenaturation of proteins; seed germination; tomato germination; Lycopersicon esculentum 相似文献
7.
Cp #2Yb (Cp #=C 5H 4(CH 2) 2NMe 2) has been obtained by reaction of YbI 2(THF) 2 with 2 equiv. of C 5H 4(CH 2CH 2NMe 2)K in THF. The X-ray structure analysis shows a bent structure with intramolecular coordination of both nitrogen atoms to ytterbium. The reaction of C 60-fullerene with Cp #2Yb leads to the formation of the fullerenide derivative [Cp #2Yb] 2C 60, which shows an ESR signal in the solid state and in THF solution at room temperature (solid: Δ H = 50 G, G = 1.9992; solution: Δ H = 10 G, G = 2.0001) and a magnetic moment of 3.6 BM. The lutetium fullerenides CpLu(C 60)(DME) (3) and Cp *Lu(C 60)(DME)(C 6H 5CH 3) (4), (Cp = η 5−C 5H 5, Cp * = η 5−C 5Me 5), were obtained by reaction of C 60 with CpLu(C 10H 8) (DME) and Cp *Lu(C 10H 8) (DME) in toluene. Both complexes are paramagnetic (μ eff = 1.4 and 0.9 BM) and exhibit temperature-dependent ESR signals (293 K: g = 1.992 and 2.0002 respectively). 相似文献
8.
Three new crystalline tin selenide salts have been prepared from the reactions of [PPh 4] 2[Sn(Se 43] in supercritical solvents. The starting material pyrolyzes in supercritical acetonitrile to form [PPh 4] 4[Sn 6Se 21] (I), and it also reacts with SnSe in supercritical ammonia leading to a mixture of [PPh 4] 4[Sn 3Se 11] 2 (II). and [PPh 4] 2[Sn(Se 4)(Se 6) 2] (III). All three compounds have been characterized by single crystal X-ray diffraction. Crystallographic data: for I, C 96H 90P 4Se 21Sn 6, space group triclinic, P-1, A = 18.763(3), B = 24.600(4), C = 13.137(1) Å, = 102.63(1), β = 93.66(1), γ = 108.72(1)°, V = 5544(1) Å 3, Z = 2, R = 0.0350, RW = 0.0317: for II, C 96H 80P 4Se 22Sn 6, space group monoclinic P2 1/ c, A = 31.500(4), B = 16.572(3), C = 22.352(3) Å, β = 103.53(1)°, V = 11344(3) Å 3, Z = 4, R = 0.0771, RW = 0.0664: for III, C 48H 40P 2Se 16Sn, space group monoclinic, C2/ c, A = 25.381(2), B = 13.934(4), C = 19.465(3) Å, β = 121.587(8)°, V = 5867(2) Å 3, Z = 4, R = 0.0807, RW = 0.0650. One of the compounds, [PPh 4] 2[Sn(Se 4(Se 62], is a molecular cluster while the other two complexes [PPh 4] 4[Sn 3Se 11] 2 and [PPh 4] 4[Sn 6Se 21], are one dimensional tin selenide chains. The structures of the two chains are related and consits of tetrahedral and distorted trigonal bipyramidal tin(IV) centers bridged by Se 2−, Se 22− and Se 32− chains. 相似文献
9.
1. 1.Hypothalamic temperature (Thy), nonevaporative heat loss (R + C + K), evaporative heat loss (E), thermal conductance (k), metabolic heat production (M) and heat storage (S) of rats were simultaneously measured by direct and indirect calorimetry during internal heat loading (2 W per rat) with an intraperitoneal electric heater. 2. 2.The tests were made twice a day; once during the day (1000–1200 h) and once at night (2200–2400 h) at an ambient temperature of 24°C. 3. 3.The resting values of Thy, colonic temperature, (R + C + K), E, M and heart rate, and the Thy threshold for tail skin vasodilation (Tth) during internal heat load were significantly higher at night than during the day. 4. 4.The slopes showing the relationshiop between (R + C + K), k or M and Thy were significantly steeper during the day than at night after Thy exceeded Tth. 5. 5.The slopes showing the relationship between E or S and Thy were not different during the day and at night. 6. 6.These results indicate that the responses of nonevaporative heat loss and heat production to internal heat load vary with the time of day in rats.
Author Keywords: Circadian rhythm; direct calorimetry; heat loss; heat storage; heat load 相似文献
10.
研究了不同方法对冬虫夏草发酵菌丝体(以枯叶蛾科昆虫马尾松毛虫为基质发酵所得)中多糖提取的影响。结果表明,采用微波辅助水提法所得多糖的产率最高,影响提取的关键因素为液料比、微波提取时间、微波功率;采用Box-Behnken设计及响应面分析法对这3个因素进行优化,并通过回归拟合,建立了预测虫草多糖提取的多项式模型 Y=6.87+0.058 A+0.085 B+0.075 C+0.032 AB+0.046 AC+0.069 BC-0.16 A2-0.37 B2-0.11 C2。经响应面最优化分析,获得冬虫夏草发酵菌丝体中多糖的最优提取工艺参数为:液料比(mL/g)6.3:1、微波功率520W、微波提取时间326s,此工艺提取验证后的提取率达到6.76%。 相似文献
11.
A number of N, N′-bis(4-substituted phenyl)-1,7-diaza-12-crown-4 and N, N′-bis(4-substituted phenyl)-1, 10-diaza-18-crown-6 (where the substituents are OCH 3, CH 3, H, Cl, respectively) have been prepared by cyclization reaction of a ditosylate with the appropriately substituted diol. These new macrocyclic ligands have been characterized by means of elemental analysis, IR, 1H NMR and MS spectra. The crystal structures of N, N′-bis(4-chlorophenyl)-1,10-diaza-18-crown-6 (21) and its complex with barium thiocyanate Ba(SCN) 2 (22) have been determined by single crystal X-ray diffraction. The crystallographic data are as follows: 21: C 24H 32Cl 2N 2O 4, orthorhombic, P2 12 12 1, A=4.852(1), B=11.989(2), C=41.231(8) Å, V=2398.7(8) Å 3, Z=4; 22: C 26H 32Cl 2N 4O 4S 2Ba, monoclinic, P2 1/ c, A=8.801(2), B=11.653(9), C=15.756(6) Å, ß=105.96(3)°, V=1553.7(14) Å 3, Z=2. In the complex, the Ba atom is eight-coordinate (O(1), O(2), O(1)′, O(2)′, N(1), N(1)′, N(21), N(21)′) to form a distorted D6h geometry with the Ba atom at the center of crystallographic symmetry. 相似文献
12.
基于干旱频率增加、强度增大这一全球降水变化背景, 探究干旱-复水条件下不同功能群(C 3和C 4)植物的光合生理响应及生长适应策略有助于预测降水格局变化条件下草地的植被组成和生态系统功能。该研究采用盆栽实验, 以松嫩草地生长的一年生C 3 (4种)和C 4 (3种)牧草为实验材料, 设置了对照、中度干旱和重度干旱3个水分处理水平, 在干旱末期及复水期对植物进行气体交换、生物量和比叶质量的测量。在干旱条件下, 各物种净光合速率和气孔导度均呈下降趋势, 水分利用效率呈上升趋势。干旱对不同植物光合指标的影响存在功能群差异, 随干旱程度的增加C 4植物逐渐丧失光合优势, 重度干旱对C 4植物净光合速率的影响较C 3植物更加明显。由于干旱条件下C 3植物光合固碳主要受气孔限制而C 4植物主要受代谢限制, 因此复水后C 4植物净光合速率恢复速度较C 3植物慢。干旱条件下, 各物种的生物量降低, 根冠比和比叶质量升高, 干旱对C 3植物各生长指标的影响均大于C 4植物; 复水处理后, C 3植物生物量随干旱强度增加呈下降趋势, 而C 4植物的生物量与对照相比无显著差异。 相似文献
13.
为深入了解玉米在关键发育期干旱条件下的耗水特征及致灾机理,对春玉米‘丹玉39’分别从拔节(T 1)和抽雄(T 2)期开始采用持续无补水方式进行干旱及复水试验,基于对叶和根水势、主要光合变量(净光合速率 Pn、蒸腾速率 Tr、气孔导度 gs、胞间CO 2浓度 Ci)以及茎流速率(SF)的动态观测,研究各生理参数对干旱及复水过程的响应特征.结果表明: 叶、根水势均与土壤湿度呈对数关系,不同时期干旱使二者都减小,对根水势的影响比叶水势提前,与拔节期相比,抽雄期叶水势的干旱响应偏早,根水势偏晚;叶水势在T 1处理复水后能得到恢复,但不能恢复到正常水平,T 2处理不能恢复;T 1处理的根水势对复水的响应比叶水势更快,且更接近于正常水平. Pn和 Tr对T 2处理的响应快于T 1处理;复水后二者对T 1处理的恢复速度快于T 2处理,T 1和T 2处理 Pn分别超过和达到正常水平,而 Tr分别能和不能达到正常水平; Tr对T 1处理的响应早于 Pn,二者对T 2处理的响应一致;各处理 gs对干旱的响应与 Pn一致;T 1处理的 Ci与 Pn趋势一致,T 2处理相反.各干旱处理SF比对照减小,在晴天比阴天响应明显,SF对T 2处理的响应比T 1处理敏感,在一定干旱水平后响应敏感性减弱;复水后SF比对照明显增大,T 2处理的增幅小于T 1处理. 相似文献
14.
Aims The correlation between vein density and water use efficiency ( WUE) affects the balance between water supply and demand of plant leaves, which is significant for comprehending the ecological adaptation strategies of plants. The objective of this study was to study how Salix matsudana modulated vein density and WUE along a soil moisture gradient in Zhangye Wetland, China. Methods The study was conducted in floodplain wetland near Heihe River in Zhangye City, Gansu Province, China. Three sample plots, at a spatial interval of 70 m, were set up along a soil moisture gradient ordinally from the area near the water body to the wetland edge, plot I (69.23%), spot II (48.38%) and spot III (35.27%). Community traits were investigated by using diagonal method, and all individuals of S. matsudana were used for measurements of height and canopy. At each plot, 5 individuals of S. matsudana at 4 vertices and diagonal intersection were selected for measurements of vein density, WUE, net photosynthetic rate ( Pn), transpiration rate ( Tr), photosynthetically active radiation ( PAR), saturated vapor pressure differences ( VPD), specific leaf area, stomatal conductance ( Gs) and intercellular CO 2 concentration ( Ci). We used mathematical methods of correlation analysis and standardized major axis to investigate relationships between vein density and WUE. Important findings With decreasing soil moisture, the height, canopy, specific leaf area, Gs and Ci of S. matsudana decreased gradually, while the vein density, WUE, Pn, Tr, PAR and VPD increased gradually. The correlation between vein density and WUE was positive in all the three plots, but the relationship varied along the soil moisture plots gradient. There was a highly significant positive correlation ( p < 0.01) between the vein density and WUE at plot I and III, whereas the correlation only reached a significant level ( p < 0.05) at plot II; The correlation coefficient between vein density and WUE is significantly smaller than 1 at plot I ( p < 0.05), while the correlation coefficient is significant greater than 1 at plot II and III ( p < 0.05). We can conclude that varied relationships between vein density and WUE of S. matsudana along a soil moisture gradient could reflect plant acclimation. 相似文献
15.
Aims The objective of the study was to evaluate the dynamics of recalcitrant components during foliar litter decomposition at different forest gap size in Pinus massoniana plantation in the low hilly land, Sichuan basin. Methods The experiment was set up by thinning P. massoniana plantation to establish seven different gap sizes (G1: 100 m 2, G2: 225 m 2, G3: 400 m 2, G4: 625 m 2, G5: 900 m 2, G6: 1225 m 2, G7: 1600 m 2). The contents of four recalcitrant components (condensed tannins, total phenol, lignin, cellulose) in foliar litter of two native species (Cinnamomum camphora and Toona ciliata) placed in litterbags at different locations in the forest gaps were evaluated. The litterbags placed under closed canopy were used as the control. Litterbags with air-dried leaves of C. camphora and T. ciliata were placed at center, edge of the gap and under the closed canopy in November 2013, and collected in December 2013, February 2014, May 2014 and August of 2014 for lab analysis. Important findings The results showed that: 1) Forest gap size had significant effect on the content of condensed tannins, total phenol and lignin for T. ciliata in gap center. However, the forest gap size had no significant effect on the content of recalcitrant components in the litters of C. camphora and cellulose content of T. ciliata. With the increase of gap size, except for cellulose content, the other three recalcitrant components content in small and medium sized gaps (G1-G5) were significant lower than in large gaps (G6, G7). 2) The condensed tannis content of T. ciliata at the gap center were significant lower than at the gap edge. The lignin contents at gap center of G3 was significant reduced in the C. camphora litter. The condensed tannins, total phenol, and lignin contents of T. ciliata litter in small and medium gaps significantly decreased. 3) The contents of the four recalcitrant components in both species’ foliar litter changed with time. The contents of condensed tannins and cellulose decreased and the content of lignin increased significantly with time, however, the total phenol content increased initially, and then decreased. Therefore, small and medium sized gaps (100-900 m 2) could be the optimal gap sizes to promote the degradation of litter recalcitrant components for two native species in P. massoniana plantations. 相似文献
16.
The structures of the complexes [PbL 2], L = 1-phenyl-3-methyl-4-acylpyrazolonato, RCOC 10H 8N 2O, R = Me (2) or Pr (3), have been determined by X-ray diffraction studies. Compound 2 is monoclinic, space group P2 1, A = 11.285(4), B = 14.727(4), C = 20.749(5) Å, β = 95.83(3)°, R = 0.039 for 4486 reflections, and 3 is monoclinic, space group C2/ c, A = 27.528(11), B = 7.245(11), C = 14.264(7) Å, β = 113.6(3)°, R = 0.021 for 2118 reflections. There are three different lead environments in 2 but only one in 3. In each case the lead atom makes four strong bonds to oxygen and two weaker bonds to either oxygen or nitrogen in adjacent molecules. 相似文献
17.
1. 1. The response of oxygen consumption (VO2), thermal conductance (Cd and Cmin, body temperature (Tb), and evaporative water loss (EWL) of Tatera leucogaster and Desmodillus auricularis were measured over the range of ambient temperatures (Ta) from 5–35°C. 2. 2. Basal metabolic rate (BMR) of T. leucogaster was 0.841 ± 0.049 ml O2 g−1 h−1 and lower than predicted, while that of D. auricularis was similar to the expected value (1.220 ± 0.058 ml O2 g−1 h−1). D. auricularis had a high, narrow thermoneutral zone (TNZ) typical of nocturnal, xerophilic, burrowing rodents. 3. 3. D. auricularis and T. leucogaster regulated Tb over the range Ta = 5–35°C and kept EWL and dry thermal conductance at a minimum below the TNZ. However, the EWL of T. leucogaster increased rapidly above Ta = 30°C. 4. 4. After comparison with data from other species, it was concluded that there is an optimum size for xeric, nocturnal, burrowing rodents.
Author Keywords: thermoregulation; BMR; gerbil 相似文献
18.
林窗通过改变森林微环境及土壤环境而影响凋落物难降解物质的降解, 目前关于人工林林窗对凋落物分解过程中难降解物质影响的研究较少。该文采用凋落物分解袋法, 以马尾松( Pinus massoniana)人工林人工砍伐形成的7个不同面积的林窗(G1: 100 m 2、G2: 225 m 2、G3: 400 m 2、G4: 625 m 2、G5: 900 m 2、G6: 1225 m 2、G7: 1600 m 2)为研究对象, 以林下为对照, 研究了林窗大小对两种乡土树种——樟( Cinnamomum camphora)和红椿( Toona ciliata)凋落叶分解过程中难降解物质(木质素、纤维素、总酚、缩合单宁)含量的影响。结果表明: 1)林窗大小对林窗中心红椿凋落叶缩合单宁、总酚、木质素的含量有显著影响, 对其纤维素含量和樟凋落叶中4种难降解物质含量均无显著影响。随着林窗面积的增大, 红椿凋落叶中除纤维素含量外的其余3种难降解物质含量, 中小型林窗(G1-G5, G1: 100 m 2, G2: 225 m 2, G3:400 m 2, G4: 625 m 2, G5: 900 m 2)低于大型林窗(G6、G7, G6: 1225 m 2, G7: 1600 m 2)。2)林窗不同位置, 只有红椿凋落叶中缩合单宁含量林窗中心显著低于边缘, 其余难降解物质含量和樟凋落叶中4种难降解物质含量均无显著差异。樟凋落叶的木质素含量在G3林窗显著低于林下; 红椿凋落叶除纤维素含量外的其余难降解物质含量, 中小型林窗从林窗中心到边缘均显著低于林下。3)随着分解时间的延长, 两种凋落叶都表现出缩合单宁、纤维素含量降低, 木质素含量升高, 总酚含量先升高后降低的变化趋势。研究结果表明: 中小型林窗(100-900 m 2)较大面积林窗干扰更有利于凋落叶中难降解物质的降解, 而林窗内的环境异质性应该是凋落物中难分解物质分解动态的主要调控因子, 并且这种效应依赖于初始凋落物质量。 相似文献
19.
The synthesis and characterization of a ferrocenyl-derived tridentate ligand, ferrocenyltris((methylthio)methyl)borate (FcTtP −), and its representative metal complexes, [(FcTt)Cu] 4 and [FcTt] 2M (M = Fe, Co and Ni), are reported. The M = Fe complex exhibits spin-crossover behavior with a μeff = 1.19 μ B at 25°C. The low-spin Co(II) derivative (1.88 μ B) exhibits a characteristic axial electron paramagnetic resonance (EPR) spectrum, gav = 2.13, A = 53 G and A¦ = 43 G. The [FcTt] 2M complexes display reversible two-electron redox processes assigned to ligand-centered events about 200 mV negative of the ferrocene-ferrocenium couple. [(FcTt)Cu] 4 and [FcTt] 2Ni have been characterized by X-ray diffraction. X-ray data for [(FcTt)Cu] 4: monoclinic space group C2/ c, with a = 24.3747(3) Å, b = 20.0857(2) Å, c = 17.2747(4) Å, β = 95.843(1)°, V = 8413.5(3) Å 3, and Z = 4; [FcTt] 2Ni: monoclinic space group C2/ c, with a = 12.6220(3) Å, b = 11.6002(3) Å, c = 25.0125(7) Å, β = 94.067(1)°, V = 3653.1(2) Å 3, and Z = 4. 相似文献
20.
Two novel C 27N 3-type Lycopodium alkaloids, cryptadines A (1) and B (2) consisting of two octahydroquinoline rings (C 11N) and a piperidine ring (C 5N), have been isolated from the club moss Lycopodium cryptomerinum, and their structures and relative stereochemistry were elucidated on the basis of spectroscopic data, chemical transformations, and computational methods. Cryptadines A (1) and B (2) exhibited an inhibitory activity against acetylcholinesterase. 相似文献
|