共查询到20条相似文献,搜索用时 31 毫秒
1.
Chao Chen Dr. Huapeng Ruan Zhongtao Feng Yong Fang Shuxuan Tang Dr. Yue Zhao Prof. Dr. Gengwen Tan Prof. Dr. Yuanting Su Prof. Dr. Xinping Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(29):11892-11897
Although diradicals and azaacenes have been greatly attractive in fundamental chemistry and functional materials, the isolable diradical dianions of azaacenes are still unknown. Herein, we describe the first isolation of pyrene-fused azaacene diradical dianion salts [(18-c-6)K(THF)2]+[(18-c-6)K]+⋅ 1 2−.. and [(18-c-6)K(THF)]2+⋅ 2 2−.. by reduction of the neutral pyrene-fused azaacene derivatives 1 and 2 with excess potassium graphite in THF in the presence of 18-crown-6. Their electronic structures were investigated by various experiments, in conjunction with theoretical calculations. It was found that both dianions are open-shell singlets in the ground state and their triplet states are thermally readily accessible owing to the small singlet–triplet energy gap. This work provides the first examples of crystalline diradical dianions of azaacenes with considerable diradical character. 相似文献
2.
Yang Min Dr. Chuandong Dou Dr. Hongkun Tian Prof. Yanhou Geng Prof. Jun Liu Prof. Lixiang Wang 《Angewandte Chemie (International ed. in English)》2018,57(7):2000-2004
We disclose a novel strategy to design n‐type acenes through the introduction of boron–nitrogen coordination bonds (B←N). We synthesized two azaacenes composed of two B←N units and six/eight linearly annelated rings. The B←N unit significantly perturbed the electronic structures of the azaacenes: Unique LUMOs delocalized over the entire acene skeletons and decreased aromaticity of the B←N‐adjacent rings. Most importantly, these B←N‐containing azaacenes exhibited low‐lying LUMO energy levels and high electron affinities, thus leading to n‐type character. The solution‐processed organic field‐effect transistor based on one such azaacene exhibited unipolar n‐type characteristics with an electron mobility of 0.21 cm2 V?1 s?1. 相似文献
3.
Benjamin E. Kucera Robert E. Jilek William W. Brennessel John E. Ellis 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(8):749-753
Reduction of VCl3(THF)3 (THF is tetrahydrofuran) and NbCl4(THF)2 by alkali metal pyrene radical anion salts in THF affords the paramagnetic sandwich complexes bis[(1,2,3,3a,10a,10b‐η)‐pyrene]vanadium(0), [V(C16H10)2], and bis[(1,2,3,3a,10a,10b‐η)‐pyrene]niobium(0), [Nb(C16H10)2]. Treatment of tris(naphthalene)titanate(2−) with pyrene provides the isoelectronic titanium species, isolated as an (18‐crown‐6)potassium salt, namely catena‐poly[[(18‐crown‐6)potassium]‐μ‐[(1,2‐η:1,2,3,3a,10a,10b‐η)‐pyrene]‐titanate(−I)‐μ‐[(1,2,3,3a,10a,10b‐η:6,7‐η)‐pyrene]], {[K(C12H24O6)][Ti(C16H10)2]}n. The first two compounds have very similar packing, with neighboring molecules arranged orthogonally to one another, such that aromatic donor–acceptor interactions are likely responsible for the specific arrangement. The asymmetric unit contains a half‐occupancy metal center η6‐coordinated to one pyrene ligand, with the full M(pyrene)2 molecule generated by a crystallographic inversion center. In the titanium compound, the cations and anions are in alternating contact throughout the crystal structure, in one‐dimensional chains along the [101] direction. As in the other two compounds, the asymmetric unit contains a half‐occupancy Ti atom η6‐coordinated to one pyrene ligand. Additionally, the asymmetric unit contains one half of an (18‐crown‐6)potassium cation, located on a crystallographic inversion center coincident with the K atom. The full formula units are generated by those inversion centers. In all three structures, the pyrene ligands are eclipsed and sandwich the metals in one of two inversion‐related sites. These species are of interest as the first isolable homoleptic pyrene transition metal complexes to be described in the scientific literature. 相似文献
4.
Zheng Zhou Zheng Wei Yuki Tokimaru Shingo Ito Kyoko Nozaki Marina A. Petrukhina 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(35):12235-12239
Mono‐ and dianions of 2‐tert‐butyl‐3a2‐azapentabenzo[bc,ef,hi,kl,no]corannulene ( 1 a ) were synthesized by chemical reduction with sodium and cesium metals, and crystallized as the corresponding salts in the presence of 18‐crown‐6 ether. X‐ray diffraction analysis of the sodium salt, [{Na+(18‐crown‐6)(THF)2}3{Na+(18‐crown‐6)(THF)}( 1 a 2?)2], revealed the presence of a naked dianion. In contrast, controlled reaction of 1 a with Cs allowed the isolation of singly and doubly reduced forms of 1 a , both forming π‐complexes with cesium ions in the solid state. In [{Cs+(18‐crown‐6)}( 1 a ?)]?THF, asymmetric binding of the Cs+ ion to the concave surface of 1 a ? is observed, whereas in [{Cs+(18‐crown‐6)}2( 1 a 2?)], two Cs+ ions bind to both the concave and convex surfaces of the dianion. The present study provides the first successful isolation and characterization of the reduced products of heteroatom‐containing buckybowl molecules. 相似文献
5.
Igor L. Fedushkin Prof. Dr. Anton N. Lukoyanov Dr. Alexandra N. Tishkina Dipl.‐Chem. Georgy K. Fukin Dr. Konstantin A. Lyssenko Prof. Dr. Markus Hummert Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(25):7563-7571
The reduction of digallane [(dpp‐bian)Ga? Ga(dpp‐bian)] ( 1 ) (dpp‐bian=1,2‐bis[(2,6‐diisopropylphenyl)imino]acenaphthene) with lithium and sodium in diethyl ether, or with potassium in THF affords compounds featuring the direct alkali metal–gallium bonds, [(dpp‐bian)Ga? Li(Et2O)3] ( 2 ), [(dpp‐bian)Ga? Na(Et2O)3] ( 3 ), and [(dpp‐bian)Ga? K(thf)5] ( 7 ), respectively. Crystallization of 3 from DME produces compound [(dpp‐bian)Ga? Na(dme)2] ( 4 ). Dissolution of 3 in THF and subsequent crystallization from diethyl ether gives [(dpp‐bian)Ga? Na(thf)3(Et2O)] ( 5 ). Ionic [(dpp‐bian)Ga]?[Na([18]crown‐6)(thf)2]+ ( 6 a ) and [(dpp‐bian)Ga]?[Na(Ph3PO)3(thf)]+ ( 6 b ) were obtained from THF after treatment of 3 with [18]crown‐6 and Ph3PO, respectively. The reduction of 1 with Group 2 metals in THF affords [(dpp‐bian)Ga]2M(thf)n (M=Mg ( 8 ), n=3; M=Ca ( 9 ), Sr ( 10 ), n=4; M=Ba ( 11 ), n=5). The molecular structures of 4 – 7 and 11 have been determined by X‐ray crystallography. The Ga? Na bond lengths in 3 – 5 vary notably depending on the coordination environment of the sodium atom. 相似文献
6.
Sebastian N. Intorp Manuel Hodecker Matthias Müller Olena Tverskoy Marco Rosenkranz Evgenia Dmitrieva Alexey A. Popov Frank Rominger Jan Freudenberg Andreas Dreuw Uwe H. F. Bunz 《Angewandte Chemie (International ed. in English)》2020,59(30):12396-12401
Quinoidal azaacenes with almost pure diradical character (y=0.95 to y=0.99) were synthesized. All compounds exhibit paramagnetic behavior investigated by EPR and NMR spectroscopy, and SQUID measurements, revealing thermally populated triplet states with an extremely low‐energy gap ΔEST′ of 0.58 to 1.0 kcal mol?1. The species are persistent in solution (half‐life≈14–21 h) and in the solid state they are stable for weeks. 相似文献
7.
A Stable Trimethylenemethane Triplet Diradical Based on a Trimeric Porphyrin Fused π‐System
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)
Kenichi Kato Prof. Dr. Ko Furukawa Prof. Dr. Atsuhiro Osuka 《Angewandte Chemie (International ed. in English)》2018,57(30):9491-9494
Trimethylenemethane (TMM) diradical is the simplest non‐Kekulé non‐disjoint molecule with the triplet ground state (ΔEST=+16.1 kcal mol?1) and is extremely reactive. It is a challenge to design and synthesize a stable TMM diradical with key properties, such as actual aliphatic TMM diradical centers and the triplet ground state with a large positive ΔEST value, since such species provide detailed information on the electronic structure of TMM diradical. Herein we report a TMM derivative, in which the TMM segment is fused with three NiII meso‐triarylporphyrins, that satisfies the above criteria. The diradical shows delocalized spin density on the propeller‐like porphyrin π‐network and the triplet ground state owing to the strong ferromagnetic interaction. Despite the apparent TMM structure, the diradical can be handled under ambient conditions and can be stored for months in the solid state, thus allowing its X‐ray diffraction structural analysis. 相似文献
8.
Observation of a Thermally Accessible Triplet State Resulting from Rotation around a Main‐Group π Bond
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)
Arseni Kostenko Dr. Boris Tumanskii Dr. Miriam Karni Prof. Shigeyoshi Inoue Prof. Masaaki Ichinohe Prof. Akira Sekiguchi Prof. Yitzhak Apeloig 《Angewandte Chemie (International ed. in English)》2015,54(41):12144-12148
We report the first direct spectroscopic observation by electron paramagnetic resonance (EPR) spectroscopy of a triplet diradical that is formed in a thermally induced rotation around a main‐group π bond, that is, the Si?Si double bond of tetrakis(di‐tert‐butylmethylsilyl)disilene ( 1 ). The highly twisted ground‐state geometry of singlet 1 allows access to the perpendicular triplet diradical 2 at moderate temperatures of 350–410 K. DFT‐calculated zero‐field splitting (ZFS) parameters of 2 accurately reproduce the experimentally observed half‐field transition. Experiment and theory suggest a thermal equilibrium between 1 and 2 with a very low singlet–triplet energy gap of only 7.3 kcal mol?1. 相似文献
9.
Dr. Cédric Boulho Dr. Harmen S. Zijlstra Alexander Hofmann Prof. Dr. Peter H. M. Budzelaar Prof. Dr. Sjoerd Harder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17450-17459
Reaction of (TBBP)AlMe ? THF with [Cp*2Zr(Me)OH] gave [(TBBP)Al(THF)?O?Zr(Me)Cp*2] (TBBP=3,3’,5,5’‐tetra‐tBu‐2,2'‐biphenolato). Reaction of [DIPPnacnacAl(Me)?O?Zr(Me)Cp2] with [PhMe2NH]+[B(C6F5)4]? gave a cationic Al/Zr complex that could be structurally characterized as its THF adduct [(DIPPnacnac)Al(Me)?O?Zr(THF)Cp2]+[B(C6F5)4]? (DIPPnacnac=HC[(Me)C=N(2,6‐iPr2?C6H3)]2). The first complex polymerizes ethene in the presence of an alkylaluminum scavenger but in the absence of methylalumoxane (MAO). The adduct cation is inactive under these conditions. Theoretical calculations show very high energy barriers (ΔG=40–47 kcal mol?1) for ethene insertion with a bridged AlOZr catalyst. This is due to an unfavorable six‐membered‐ring transition state, in which the methyl group bridges the metal and ethene with an obtuse metal‐Me‐C angle that prevents synchronized bond‐breaking and making. A more‐likely pathway is dissociation of the Al‐O‐Zr complex into an aluminate and the active polymerization catalyst [Cp*2ZrMe]+. 相似文献
10.
Based on the previously reported one‐dimensional channel system [(H2O)?(DB18C6)(μ2‐H2O)2/2][(H3O)?(DB18C6)(μ2‐H2O)2/2]I3 ( 2 ), which is realized by stacking of crown ether molecules (DB18C6 = dibenzo‐18‐crown‐6), other synthetic approaches towards ionic channels and their results are presented in this paper. The “cutting out” approach using DB18C6 as scissor, applied on NaI, yields the compound [Na?(DB18C6)I(THF)][Na?(DB18C6)(H2O)2]I(THF)2(CHI3) ( 1 ), in high yield. It is based on a neutral and a cationic complex of sodium by DB18C6 linked via H‐bonding to give short chain fragments. The anion exchange approach, trying to replace I3? by Br3? leads to the intercalation of a cation into a DB18C6 chain in [(Me3NPh)(DB18C6)]Br3 ( 3 ). A similar reaction as for the synthesis of 2 , but replacing iodide with bromine, yields finally a brominated DB18C6 ligand. In the presence of iron, the compound [(H5O2)?(Br4‐DB18C6)2][FeBr4], 4 , is observed, in which a H5O2+‐cation is encapsuled by two brominated crown ether molecules. The absence of Fe and an excess of Br2 leads to the complexation of H3O+, and co‐crystallisation of bromine in [(H3O)?(Br4‐DB18C6)]Br3Br2 ( 5 ). 相似文献
11.
Dmitri V. Konarev Alexey V. Kuzmin Salavat S. Khasanov Alexey A. Goryunkov Victor A. Brotsman Ilya N. Ioffe Akihiro Otsuka Hideki Yamochi Hiroshi Kitagawa Rimma N. Lyubovskaya 《化学:亚洲杂志》2019,14(11):1958-1964
Radical anion salt {cryptand[2.2.2] (K+)}2(bispheroid)2??3.5C6H4Cl2 ( 1 ) of the double‐caged fullerene C60 derivative, in which fullerene cages are linked by a cyclobutane bridging cycle and additionally by a pyrrolizidine moiety, was obtained. Each fullerene cage in this derivative accepts one electron on reduction, thus forming the (bispheroid)2? dianions with two interacting S=1/2 spins on the neighboring cages. Low‐temperature magnetic measurements reveal a singlet ground state of the bispheroid dianions whereas triplet contributions prevail at increased temperature. An estimated exchange interaction between two spins J/kB=?78 K in 1 indicates strong magnetic coupling between them, nearly two times higher than that (J/kB=?44.7 K) in previously studied (C60?)2 dimers linked via a cyclobutane bridge only. The enhancement of magnetic coupling in 1 can be explained by a shorter distance between the fullerene cages and, possibly, an additional channel for the magnetic exchange provided by a pyrrolizidine bridge. Quantum‐chemical calculations of the lowest electronic state of the dianions by means of multi‐configuration quasi‐degenerate perturbation theory support the experimental findings. 相似文献
12.
In this account, the synthesis and applications of pyrene‐fused acenes, as well as pyrene‐fused azaacenes, have been carefully reviewed. Moreover, the synthetic methods involving two key synthons (different lengths of dienes and ynes) have been included. Furthermore, the “clean reaction” strategy has been introduced for the preparation of pyrene‐fused acenes with a single terminal‐pyrene unit from tetracene to octacene, as well as for the synthesis of pyrene‐fused octatwistacenes and nonatwistacenes with double terminal‐pyrene units. Similarly, the synthons and the synthetic methods for pyrene‐fused azaacenes have also been summarized. The applications of pyrene‐fused acenes and pyrene‐fused azaacenes have been included. 相似文献
13.
Dinuclear Palladium Complexes with Two Ligand‐Centered Radicals and a Single Bridging Ligand: Subtle Tuning of Magnetic Properties
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)
M. Sc. Daniël L. J. Broere Dr. Serhiy Demeshko Prof. Dr. Bas de Bruin Dr. Evgeny A. Pidko Prof. Dr. Joost N. H. Reek Dr. Maxime A. Siegler Dr. Martin Lutz Dr. Jarl Ivar van der Vlugt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5879-5886
The facile and tunable preparation of unique dinuclear [(L?)Pd?X?Pd(L?)] complexes (X=Cl or N3), bearing a ligand radical on each Pd, is disclosed, as well as their magnetochemistry in solution and solid state is reported. Chloride abstraction from [PdCl( NNOISQ )] ( NNOISQ =iminosemiquinonato) with TlPF6 results in an unusual monochlorido‐bridged dinuclear open‐shell diradical species, [{Pd( NNO ISQ)}2(μ‐Cl)]+, with an unusually small Pd‐Cl‐Pd angle (ca. 93°, determined by X‐ray). This suggests an intramolecular d8–d8 interaction, which is supported by DFT calculations. SQUID measurements indicate moderate antiferromagnetic spin exchange between the two ligand radicals and an overall singlet ground state in the solid state. VT EPR spectroscopy shows a transient signal corresponding to a triplet state between 20 and 60 K. Complex 2 reacts with PPh3 to generate [Pd(NNOISQ)(PPh3)]+ and one equivalent of [PdCl( NNOISQ )]. Reacting an 1:1 mixture of [PdCl( NNOISQ )] and [Pd(N3)( NNOI SQ)] furnishes the 1,1‐azido‐bridged dinuclear diradical [{Pd( NNO ISQ)}2(κ1‐N;μ‐N3]+, with a Pd‐N‐Pd angle close to 127° (X‐ray). Magnetic and EPR measurements indicate two independent S=1/2 spin carriers and no magnetic interaction in the solid state. The two diradical species both show no spin exchange in solution, likely because of unhindered rotation around the Pd?X?Pd core. This work demonstrates that a single bridging atom can induce subtle and tunable changes in structural and magnetic properties of novel dinuclear Pd complexes featuring two ligand‐based radicals. 相似文献
14.
Shuxuan Tang Huapeng Ruan Rui Feng Yue Zhao Gengwen Tan Li Zhang Xinping Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(50):18392-18397
The reduction of 2,4,6‐tri(4‐pyridyl)‐1,3,5‐triazine (TPT) with alkali metals resulted in four radical anion salts ( 1 , 2 , 4 and 5 ) and one diradical dianion salt ( 3 ). Single‐crystal X‐ray diffraction and electron paramagnetic resonance (EPR) spectroscopy reveal that 1 contains the monoradical anion TPT.? stacked in one‐dimensional (1D) with K+(18c6) and 2 can be viewed as a 1D magnetic chain of TPT.?, while 4 and 5 form radical metal‐organic frameworks (RMOFs). 1D pore passages, with a diameter of 6.0 Å, containing solvent molecules were observed in 5 . Variable‐temperature EPR measurements show that 3 has an open‐shell singlet ground state that can be excited to a triplet state, consistent with theoretical calculation. The work suggests that the direct reduction approach could lead to the formation of RMOFs. 相似文献
15.
The complex, bis[N‐6‐aminopyridyl‐N‐(1S)‐(+)‐10‐camphorsulfonylamino]palladium, Pd[(S)‐APCS]2, 1 , was prepared by reaction of 2‐[(1S)‐(+)‐10‐camphorsulfonamino]‐6‐aminopyridine with PdCl2 in THF. Complex 1 has been characterized by spectroscopic methods and its structure has been determined by X‐ray crystallography. Crystal data: space group C2, a= 16.082 (2), b = 17.104 (2), c = 13.051 (2)Å, β = 99.95 (1)°, V = 3535.9 (8) Å3, Z = 2 with final residuals R1 = 0.0491 and wR2 = 0.0944. Two independent molecules, (S,S)‐Pd[(S)‐APCS]2, 1a , and (R,R)‐Pd[(S)‐APCS]2, 1b , were found in each asymmetric unit, which exchange to each other via a series of nitrogen inversion and C‐C bond rotation. The inversion energy (ΔGc1≠) and the energy barrier (δGc2≠) were 11.5 ± 0.1 Kcal mol?1 at 246 K and 9.8 ± 0.1 Kcal mol?1 at 199 K, respectively, calculated by dynamic NMR data. 相似文献
16.
Dr. Gang Li Yuechao Wu Dr. Junkuo Gao Junbo Li Prof. Dr. Yang Zhao Prof. Dr. Qichun Zhang 《化学:亚洲杂志》2013,8(7):1574-1578
Two novel larger azaacenes with six or ten N atoms in their backbones, benzannelated 9,11,13,22,24,26‐hexazatetrabenzo[a,c,l,n]heptacene ( HATBH , 1 ) and benzannelated 9,26‐dihydro‐9,11,13,22,24,26‐hexaza‐tetrapyrido[3,2‐a: 2′,3′‐c: 3′′,2′′‐l: 2′′′,3′′′‐n]heptacene ( DHATPH, 2 ), have been successfully synthesized in two steps. The theoretical band gaps estimated through DFT calculations for HATBH ( 1 ) and DHATPH ( 2 ) are 1.949 eV and 2.278 eV, which are close to the experimentally obtained optical band gaps (2.14 eV and 2.39 eV). Interestingly, HATBH ( 1 ) can act as efficient anion sensor for F? and H2PO4?, while DHATPH ( 2 ) selectively responds to F? among the ten different anions used (F?, Cl?, Br?, I?, PF6?, HSO4?, NO3?, BF4?, AcO?, and H2PO4?). Our synthetic strategy could offer a promising and easy way to obtain even larger azaacenes. 相似文献
17.
Cheng Zhang Samara MedinaRivero Wuyue Liu David Casanova Xiaozhang Zhu Juan Casado 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(33):11413-11417
A tetracyano quinoidal tetrathiophene, having a central bi(thieno[3,4‐c]pyrrole‐4,6‐dione) acceptor, has been studied. The recovered aromaticity of the thiophenes produces a diradical species with cross‐conjugation between the inter‐dicyano and inter‐dione acceptor paths. A diradical character of y0=0.61 and a singlet–triplet gap of ?2.76 kcal mol?1 were determined. Competition between the two cross‐conjugated paths enhances the disjointed character of the SOMOs and results in the confinement of the diradical to the molecular center, enabling a thermodynamic diradical stabilization featuring a half‐life of 262 hours. Cross‐conjugation effects have been also addressed in the anionic species (up to a radical trianion). 相似文献
18.
Konu J Chivers T Tuononen HM 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(42):11844-11856
The metathetical reactions of a) [Li(tmeda)]2[(S)C(PPh2S)2] (Li2? 3 c ) with CuCl2 and b) [Li(tmeda)]2[(SPh2P)2CSSC(PPh2S)2] (Li2? 4 c ) with two equivalents of CuCl both afford the binuclear CuI complex {Cu2[(SPh2P)2CSSC(PPh2S)2]} ( 5 c ). The elongated (C)S? S(C) bond (ca. 2.54 and 2.72 Å) of the dianionic ligand observed in the solid‐state structure of 5 c indicate the presence of diradical character as supported by theoretical analyses. The treatment of [Li(tmeda)]2[(SPh2P)2CSeSeC(PPh2S)2] (Li2? 4 b ) and Li2? 4 c with AgOSO2CF3 produce the analogous AgI derivatives, {Ag2[(SPh2P)2CEEC(PPh2S)2]} ( 6 b , E=Se; 6 c , E=S), respectively. The diselenide complex 6 b exhibits notably weaker Ag? Se(C) bonds than the corresponding contacts in the CuI congeners, and the 31P NMR data suggest a possible isomerization in solution. In contrast to the metathesis observed for CuI and AgI reagents, the reactions of Li2? 4 b and Li2? 4 c with Au(CO)Cl involve a redox process in which the dimeric dichalcogenide ligands are reduced to the corresponding monomeric dianions, [(E)C(PPh2S)2]2? ( 3 b , E=Se; 3 c , E=S), and one of the gold centers is oxidized to generate the mixed‐valent AuI/AuIII complexes, {Au[(E)C(PPh2S)2]}2 ( 7 b , E=Se; 7 c , E=S), with relatively strong aurophilic AuI???AuIII interactions. The new compounds 5 c , 6 b , c and 7 b , c are characterized in solution by NMR spectroscopy and in the solid state by X‐ray crystallography ( 5 c , 6 b , 7 b and 7 c ) and by Raman spectroscopy ( 5 c and 6 c ). The UV‐visible spectra of coinage metal complexes of the type 5 , 6 and 7 are discussed in the light of results from theoretical analyses using time‐dependent density functional theory. 相似文献
19.
Synthesis and Crystal Structure of [(n‐Bu)4N][W6Cl18] Single‐crystals of [(n‐Bu)4N][W6Cl18] were obtained as thin needles by adding methanol to a solution of W6Cl18 and [(n‐Bu)4N]Cl in tetrahydrofuran. The structure was determined by single‐crystal X‐ray diffraction at 210 K. [(n‐Bu)4N][W6Cl18] crystallizes in the monoclinic space group C 2/c with Z = 8 and the lattice parameters a = 2175.6(1) pm, b = 1738.0(1) pm, c = 2160.36(9) pm, and β = 91.680(5) °. The crystal structure contains isolated [(W6Cl12i)Cl6a]— clusters and [(n‐Bu)4N]+ ions. 相似文献
20.
Strong Exchange Coupling in a Trimetallic Radical‐Bridged Cobalt(II)‐Hexaazatrinaphthylene Complex
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)
Dr. Jani O. Moilanen Dr. Nicholas F. Chilton Dr. Benjamin M. Day Dr. Thomas Pugh Prof. Dr. Richard A. Layfield 《Angewandte Chemie (International ed. in English)》2016,55(18):5521-5525
Reducing hexaazatrinaphthylene (HAN) with potassium in the presence of 18‐c‐6 produces [{K(18‐c‐6)}HAN], which contains the S=1/2 radical [HAN].?. The [HAN].? radical can be transferred to the cobalt(II) amide [Co{N(SiMe3)2}2], forming [K(18‐c‐6)][(HAN){Co(N′′)2}3]; magnetic measurements on this compound reveal an S=4 spin system with strong cobalt–ligand antiferromagnetic exchange and J≈?290 cm?1 (?2 J formalism). In contrast, the CoII centres in the unreduced analogue [(HAN){Co(N′′)2}3] are weakly coupled (J≈?4.4 cm?1). The finding that [HAN].? can be synthesized as a stable salt and transferred to cobalt introduces potential new routes to magnetic materials based on strongly coupled, triangular HAN building blocks. 相似文献