共查询到20条相似文献,搜索用时 390 毫秒
1.
2.
From para‐Benziporphyrin to Rhodium(III) 21‐Carbaporphyrins: Imprinting Rh⋅⋅⋅η2‐CC,Rh⋅⋅⋅η2‐CO,and Rh⋅⋅⋅η2‐CH Coordination Motifs
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Aneta Idec Dr. Ludmiła Szterenberg Prof. Lechosław Latos‐Grażyński 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(35):12481-12487
Rhodium(III) para‐benziporphyrin alters the fundamental reactivity of the built‐in para‐phenylene moiety. Due to additional macrocyclic stabilization, a sequence of intramolecular rearrangements are triggered to afford rhodium(III) 21‐carbaporphyrin, which incorporates the rhodacyclopropane motif. The peculiar reversible transformations of the bridging methylene unit provide an example of selective and reversible aliphatic C?H bond elimination. Rhodium(III) 21‐carbaporphyrin can be oxygenated to rhodium(III) 21‐oxy‐21‐carbaporphyrin, whereas the metal ion interacts with the C(21)?O(25) fragment in an η2 fashion. This species demonstrates a remarkable axial affinity toward alkenes. 相似文献
3.
4.
Elke Duchardt‐Ferner Jan Ferner Jens Whnert 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2011,123(34):8073-8076
5.
6.
Seung‐Kyun Noh Jeong Heum Jeon Won Jun Jang Dr. Howon Kim Soon‐Hyeong Lee Min Wook Lee Prof. Jhinhwan Lee Prof. Seungwu Han Prof. Se‐Jong Kahng 《Chemphyschem》2013,14(6):1177-1181
The role of halogen bonds in self‐assembled networks for systems with Br and I ligands has recently been studied with scanning tunneling microscopy (STM), which provides physical insight at the atomic scale. Here, we study the supramolecular interactions of 1,5‐dichloroanthraquinone molecules on Au(111), including Cl ligands, by using STM. Two different molecular structures of chevron and square networks are observed, and their molecular models are proposed. Both molecular structures are stabilized by intermolecular Cl???H and O???H hydrogen bonds with marginal contributions from Cl‐related halogen bonds, as revealed by density functional theory calculations. Our study shows that, in contrast to Br‐ and I‐related halogen bonds, Cl‐related halogen bonds weakly contribute to the molecular structure due to a modest positive potential (σ hole) of the Cl ligands. 相似文献
7.
M. Sc. Lotta Turunen M. Sc. Ulrike Warzok Dr. Rakesh Puttreddy Dr. Ngong Kodiah Beyeh Prof. Christoph A. Schalley Acad. Prof. Kari Rissanen 《Angewandte Chemie (International ed. in English)》2016,55(45):14033-14036
Two [N???I+???N] halogen‐bonded dimeric capsules using tetrakis(3‐pyridyl)ethylene cavitands with different lower rim alkyl chains are synthesized and analyzed in solution and the gas phase. These first examples of symmetrical dimeric capsules making use of the iodonium ion (I+) as the main connecting module are characterized by 1H NMR spectroscopy, diffusion ordered NMR spectroscopy (DOSY), electrospray ionization mass spectrometry (ESI‐MS), and ion mobility‐mass spectrometry (TW‐IMS) experiments. The synthesis and effective halogen‐bonded dimerization proceeds through analogous dimeric capsules with [N???Ag+???N] binding motifs as the intermediates as evidenced by the X‐ray structures of (CH2Cl2)2@[ 3 a 2?Ag4?(H2O)2?OTs4] and (CH2Cl2)2@[ 3 a 2?Ag4?(H2O)4?OTs4], two structurally different capsules. 相似文献
8.
OH⋅⋅⋅N and CH⋅⋅⋅O Hydrogen Bonds Control Hydration of Pivotal Tropane Alkaloids: Tropinone⋅⋅⋅H2O Complex
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Patricia Écija Montserrat Vallejo‐López Dr. Luca Evangelisti Dr. José A. Fernández Prof. Dr. Alberto Lesarri Prof. Dr. Walther Caminati Dr. Emilio J. Cocinero 《Chemphyschem》2014,15(5):918-923
The effect of monohydration in equatorial/axial isomerism of the common motif of tropane alkaloids is investigated in a supersonic expansion by using Fourier‐transform microwave spectroscopy. The rotational spectrum reveals the equatorial isomer as the dominant species in the tropinone???H2O complex. The monohydrated complex is stabilized primarily by a moderate O?H???N hydrogen bond. In addition, two C?H???O weak hydrogen bonds also support this structure, blocking the water molecule and avoiding any molecular dynamics in the complex. The water molecule acts as proton donor and chooses the ternary amine group over the carbonyl group as a proton acceptor. The experimental work is supported by theoretical calculations; the accuracy of the B3LYP, M06‐2X, and MP2 methods is also discussed. 相似文献
9.
10.
11.
12.
13.
14.
Prof. Yanli Zeng Dr. Wenjie Wu Dr. Xiaoyan Li Prof. Shijun Zheng Prof. Lingpeng Meng 《Chemphyschem》2013,14(8):1591-1600
The influences of the Li???π interaction of C6H6???LiOH on the H???π interaction of C6H6???HOX (X=F, Cl, Br, I) and the X???π interaction of C6H6???XOH (X=Cl, Br, I) are investigated by means of full electronic second‐order Møller–Plesset perturbation theory calculations and “quantum theory of atoms in molecules” (QTAIM) studies. The binding energies, binding distances, infrared vibrational frequencies, and electron densities at the bond critical points (BCPs) of the hydrogen bonds and halogen bonds prove that the addition of the Li???π interaction to benzene weakens the H???π and X???π interactions. The influences of the Li???π interaction on H???π interactions are greater than those on X???π interactions; the influences of the H???π interactions on the Li???π interaction are greater than X???π interactions on Li???π interaction. The greater the influence of Li???π interaction on H/X???π interactions, the greater the influences of H/X???π interactions on Li???π interaction. QTAIM studies show that the intermolecular interactions of C6H6???HOX and C6H6???XOH are mainly of the π type. The electron densities at the BCPs of hydrogen bonds and halogen bonds decrease on going from bimolecular complexes to termolecular complexes, and the π‐electron densities at the BCPs show the same pattern. Natural bond orbital analyses show that the Li???π interaction reduces electron transfer from C6H6 to HOX and XOH. 相似文献
15.
Juan Forniés Violeta Sicilia Pilar Borja José M. Casas Alvaro Díez Elena Lalinde Carmen Larraz Antonio Martín M. Teresa Moreno 《化学:亚洲杂志》2012,7(12):2813-2823
The neutral compounds [Pt(bzq)(CN)(CNR)] (R=tBu ( 1 ), Xyl ( 2 ), 2‐Np ( 3 ); bzq= benzoquinolate, Xyl=2,6‐dimethylphenyl, 2‐Np=2‐napthyl) were isolated as the pure isomers with a trans‐Cbzq,CNR configuration, as confirmed by 13C{1H} NMR spectroscopy in the isotopically marked [Pt(bzq)(13CN)(CNR)] (R=tBu ( 1′ ), Xyl ( 2′ ), 2‐Np ( 3′ )) derivatives (δ13CCN≈110 ppm; 1J(Pt,13C)≈1425 Hz]. By contrast, complex [Pt(bzq)(C≡CPh)(CNXyl)] ( 4 ) with a trans‐Nbzq,CNR configuration, has been selectively isolated from [Pt(bzq)Cl(CNXyl)] (trans‐Nbzq,CNR) using Sonogashira conditions. X‐ray diffraction studies reveal that while 1 adopts a columnar‐stacked chain structure with Pt–Pt distances of 3.371(1) Å and significant π???π interactions (3.262 Å), complex 2 forms dimers supported only by short Pt???Pt (3.370(1) Å) interactions. In complex 4 the packing is directed by weak bzq???Xyl and bzq???C≡E (C, N) interactions. In solid state at room temperature, compounds 1 and 2 both show a bright red emission (?=42.1 % 1 , 57.6 % 2 ). Luminescence properties in the solid state at 77 K and concentration‐dependent emission studies in CH2Cl2 at 298 K and at 77 K are also reported for 1 , 1·CHCl3 , 2 , 2' , 2·CHCl3 , 3 , 4 . 相似文献
16.
17.
Chirality Induction and Amplification in the 2,2,2‐Trifluoroethanol⋅⋅⋅Propylene Oxide Adduct
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Javix Thomas Prof. Dr. Wolfgang Jäger Prof. Dr. Yunjie Xu 《Angewandte Chemie (International ed. in English)》2014,53(28):7277-7280
Chirality induction and amplification in a model system, that is, the 2,2,2‐trifluoroethanol (TFE)???propylene oxide (PO) adduct, were investigated using free‐space and cavity‐based Fourier transform microwave spectroscopy, complemented with high level ab initio calculations. Rotational spectra of four out of eight predicted TFE??PO adducts were assigned, and the remaining four were shown to relax to the geometries of the four observed in a jet expansion. The g+ TFE???S‐PO adduct was found to be favored over that of g? TFE???S‐PO by a factor of 2.8 at 60 K. This difference contrasts the TFE dimer for which an extreme case of chirality synchronization was previously reported. All TFE???PO conformers observed take on the open arrangement, in contrast to 2‐fluoroethanol???PO, which prefers the closed arrangement. Furthermore, perfluorination at CH3 increases the hydrogen‐bonding energy by about 70 % over its ethanol counterpart. 相似文献
18.
Marc Mosrin M. Sc. Paul Knochel Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(6):1468-1477
Efficient zincation and magnesiation of chlorinated pyrimidines can be performed at convenient temperatures (e.g., 25 and 55 °C) by using TMPMgCl?LiCl and TMP2Zn?2 M gCl2?2 LiCl (TMP=2,2,6,6‐tetramethylpiperidyl) as effective bases. Quenching of the resulting zincated or magnesiated pyrimidines with various electrophiles furnishes highly functionalized pyrimidines in 51–93 % yield. Oxidative aminations were carried out, thus leading to aminated pyrimidines. By using this methodology, we have also prepared pharmaceutically relevant pyrazolopyrimidines and the fungicide Mepanipyrim. 相似文献
19.