共查询到20条相似文献,搜索用时 15 毫秒
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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
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Construction of Hetero‐Four‐Layered Tripalladium(II) Cyclophanes by Transannular π⋅⋅⋅π Interactions 下载免费PDF全文
Haeri Lee Dr. Tae Hwan Noh Prof. Dr. Ok‐Sang Jung 《Angewandte Chemie (International ed. in English)》2016,55(3):1005-1009
A synthetic strategy for the generation of new molecular species utilizing a provision of nature is presented. Nano‐dimensional (23(2)×21(1)×16(1) Å3) hetero‐four‐layered trimetallacyclophanes were constructed by proof‐of‐concept experiments that utilize a suitable combination of π???π interactions between the central aromatic rings, tailor‐made short/long spacer tridentate donors, and the combined helicity. The behavior of the unprecedented four‐layered metallacyclophane system offers a landmark in the development of new molecular systems. 相似文献
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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
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Wei‐Long Shan Yue‐Jian Lin F. Ekkehardt Hahn Guo‐Xin Jin 《Angewandte Chemie (International ed. in English)》2019,58(18):5882-5886
A series of molecular metalla[2]catenanes featuring Cp*Ir vertices have been prepared by the template‐free, coordination‐driven self‐assembly of dinuclear iridium acceptors and 1,5‐bis[2‐(4‐pyridyl)ethynyl]anthracene donors. The metalla[2]catenanes were formed by using a strategically selected linker type that is capable of participating in sandwich‐type π–π stacking interactions. In the solid state, the [2]catenanes adopt two different configurations depending on the halogen atoms at the dinuclear metal complex bridge. Altering the solvent or the concentration, as well as the addition of guest molecules, enabled controlled transformations between metalla[2]catenanes and tetranuclear metallarectangles. 相似文献
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Sagar Sharma Rajesh S. Baligar Harkesh B. Singh Prof. Ray J. Butcher Prof. 《Angewandte Chemie (International ed. in English)》2009,48(11):1987-1990
All wrapped up : The reaction of a 22‐membered macrocycle derived from bis(o‐formylphenyl)mercury and 1,2‐phenylenediamine with palladium(II) results in cleavage of the macrocycle and concomitant formation of a trimetallic complex (see picture; phenyl rings truncated for clarity). The nature of the HgII???PdII???HgII interaction was investigated by theoretical studies.
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Self‐Assembly and (Hydro)gelation Triggered by Cooperative π–π and Unconventional CH⋅⋅⋅X Hydrogen Bonding Interactions 下载免费PDF全文
Christina Rest Dr. María José Mayoral Dr. Katharina Fucke Jennifer Schellheimer Dr. Vladimir Stepanenko Dr. Gustavo Fernández 《Angewandte Chemie (International ed. in English)》2014,53(3):700-705
Weak C? H???X hydrogen bonds are important stabilizing forces in crystal engineering and anion recognition in solution. In contrast, their quantitative influence on the stabilization of supramolecular polymers or gels has thus far remained unexplored. Herein, we report an oligophenyleneethynylene (OPE)‐based amphiphilic PtII complex that forms supramolecular polymeric structures in aqueous and polar media driven by π–π and different weak C‐H???X (X=Cl, O) interactions involving chlorine atoms attached to the PtII centers as well as oxygen atoms and polarized methylene groups belonging to the peripheral glycol chains. A collection of experimental techniques (UV/Vis, 1D and 2D NMR, DLS, AFM, SEM, and X‐Ray diffraction) demonstrate that the interplay between different weak noncovalent interactions leads to the cooperative formation of self‐assembled structures of high aspect ratio and gels in which the molecular arrangement is maintained in the crystalline state. 相似文献
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Anthony Yiu‐Yan Tam Keith Man‐Chung Wong Dr. Vivian Wing‐Wah Yam Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(19):4775-4778
Helical superstructures : A series of luminescent chiral alkynylplatinum(II)–terpyridyl complexes has been successfully synthesised and shown to be capable of forming metallogels that show helical fibrous nanostructures. The chiral supramolecular structure and the spectroscopic properties are found to depend on the extent of aggregation through Pt???Pt and π–π interactions in various counteranions, as revealed by UV/Vis, circular dichroism (CD), and luminescence studies (see picture).
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(26):7672-7675
Protein structure and function is dependent on myriad noncovalent interactions. Direct detection and characterization of these weak interactions in large biomolecules, such as proteins, is experimentally challenging. Herein, we report the first observation and measurement of long‐range “through‐space” scalar couplings between methyl and backbone carbonyl groups in proteins. These J couplings are indicative of the presence of noncovalent C−H⋅⋅⋅π hydrogen‐bond‐like interactions involving the amide π network. Experimentally detected scalar couplings were corroborated by a natural bond orbital analysis, which revealed the orbital nature of the interaction and the origins of the through‐space J couplings. The experimental observation of this type of CH⋅⋅⋅π interaction adds a new dimension to the study of protein structure, function, and dynamics by NMR spectroscopy. 相似文献
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Chavdar Slavov Chong Yang Andreas H. Heindl Hermann A. Wegner Andreas Dreuw Josef Wachtveitl 《Angewandte Chemie (International ed. in English)》2020,59(1):380-387
Azoheteroarene photoswitches have attracted attention due to their unique properties. We present the stationary photochromism and ultrafast photoisomerization mechanism of thiophenylazobenzene (TphAB). It demonstrates impressive fatigue resistance and photoisomerization efficiency, and shows favorably separated (E)‐ and (Z)‐isomer absorption bands, allowing for highly selective photoconversion. The (Z)‐isomer of TphAB adopts an unusual orthogonal geometry where the thiophenyl group is perfectly perpendicular to the phenyl group. This geometry is stabilized by a rare lone‐pair???π interaction between the S atom and the phenyl group. The photoisomerization of TphAB occurs on the sub‐ps to ps timescale and is governed by this interaction. Therefore, the adoption and disruption of the orthogonal geometry requires significant movement along the inversion reaction coordinates (CNN and NNC angles). Our results establish TphAB as an excellent photoswitch with versatile properties that expand the application possibilities of AB derivatives. 相似文献
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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