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Trinuclear [CoIII2–LnIII] (Ln=Tb,Dy) Single‐Ion Magnets with Mixed 6‐Chloro‐2‐Hydroxypyridine and Schiff Base Ligands 下载免费PDF全文
Prof. Dr. Cai‐Ming Liu Prof. Dr. De‐Qing Zhang Prof. Dr. Xiang Hao Prof. Dao‐Ben Zhu 《化学:亚洲杂志》2014,9(7):1847-1853
The Schiff base ligand N1,N3‐bis(3‐methoxysalicylidene)diethylenetriamine (H2valdien) and the co‐ligand 6‐chloro‐2‐hydroxypyridine (Hchp) were used to construct two 3d–4f heterometallic single‐ion magnets [Co2Dy(valdien)2(OCH3)2(chp)2] ? ClO4 ? 5 H2O ( 1 ) and [Co2Tb(valdien)2(OCH3)2(chp)2] ? ClO4 ? 2 H2O ? CH3OH ( 2 ). The two trinuclear [CoIII2LnIII] complexes behave as a mononuclear LnIII magnetic system because of the presence of two diamagnetic cobalt(III) ions. Complex 1 has a molecular symmetry center, and it crystallizes in the C2/c space group, whereas complex 2 shows a lower molecular symmetry and crystallizes in the P21/c space group. Magnetic investigations indicated that both complexes are field‐induced single‐ion magnets, and the CoIII2–DyIII complex possesses a larger energy barrier [74.1(4.2) K] than the CoIII2–TbIII complex [32.3(2.6) K]. 相似文献
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Two C3‐Symmetric Dy3III Complexes with Triple Di‐μ‐methoxo‐μ‐phenoxo Bridges,Magnetic Ground State,and Single‐Molecule Magnetic Behavior 下载免费PDF全文
Dr. Mikko M. Hänninen Prof. Dr. Antonio J. Mota Dr. Daniel Aravena Prof. Dr. Eliseo Ruiz Prof. Dr. Reijo Sillanpää Dr. Agustín Camón Dr. Marco Evangelisti Prof. Dr. Enrique Colacio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(27):8410-8420
Two series of isostructural C3‐symmetric Ln3 complexes Ln3 ? [BPh4] and Ln3 ? 0.33[Ln(NO3)6] (in which LnIII=Gd and Dy) have been prepared from an amino‐bis(phenol) ligand. X‐ray studies reveal that LnIII ions are connected by one μ2‐phenoxo and two μ3‐methoxo bridges, thus leading to a hexagonal bipyramidal Ln3O5 bridging core in which LnIII ions exhibit a biaugmented trigonal‐prismatic geometry. Magnetic susceptibility studies and ab initio complete active space self‐consistent field (CASSCF) calculations indicate that the magnetic coupling between the DyIII ions, which possess a high axial anisotropy in the ground state, is very weakly antiferromagnetic and mainly dipolar in nature. To reduce the electronic repulsion from the coordinating oxygen atom with the shortest Dy?O distance, the local magnetic moments are oriented almost perpendicular to the Dy3 plane, thus leading to a paramagnetic ground state. CASSCF plus restricted active space state interaction (RASSI) calculations also show that the ground and first excited state of the DyIII ions are separated by approximately 150 and 177 cm?1, for Dy3 ? [BPh4] and Dy3 ? 0.33[Dy(NO3)6], respectively. As expected for these large energy gaps, Dy3 ? [BPh4] and Dy3 ? 0.33[Dy(NO3)6] exhibit, under zero direct‐current (dc) field, thermally activated slow relaxation of the magnetization, which overlap with a quantum tunneling relaxation process. Under an applied Hdc field of 1000 Oe, Dy3 ? [BPh4] exhibits two thermally activated processes with Ueff values of 34.7 and 19.5 cm?1, whereas Dy3 ? 0.33[Dy(NO3)6] shows only one activated process with Ueff=19.5 cm?1. 相似文献
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Multifunctionality in Bimetallic LnIII[WV(CN)8]3− (Ln=Gd,Nd) Coordination Helices: Optical Activity,Luminescence, and Magnetic Coupling 下载免费PDF全文
Szymon Chorazy Dr. Koji Nakabayashi Mirosław Arczynski Dr. Robert Pełka Prof. Shin‐ichi Ohkoshi Prof. Barbara Sieklucka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(23):7144-7159
Two chiral luminescent derivatives of pyridine bis(oxazoline) (Pybox), (SS/RR)‐iPr‐Pybox (2,6‐bis[4‐isopropyl‐2‐oxazolin‐2‐yl]pyridine) and (SRSR/RSRS)‐Ind‐Pybox (2,6‐bis[8H‐indeno[1,2‐d]oxazolin‐2‐yl]pyridine), have been combined with lanthanide ions (Gd3+, Nd3+) and octacyanotungstate(V) metalloligand to afford a remarkable series of eight bimetallic CN?‐bridged coordination chains: {[LnIII(SS/RR‐iPr‐Pybox)(dmf)4]3[WV(CN)8]3}n ? dmf ? 4 H2O (Ln=Gd, 1 ‐SS and 1 ‐RR; Ln=Nd, 2 ‐SS and 2 ‐RR) and {[LnIII(SRSR/RSRS‐Ind‐Pybox)(dmf)4][WV(CN)8]}n ? 5 MeCN ? 4 MeOH (Ln=Gd, 3 ‐SRSR and 3 ‐RSRS; Ln=Nd, 4 ‐SRSR and 4 ‐RSRS). These materials display enantiopure structural helicity, which results in strong optical activity in the range 200–450 nm, as confirmed by natural circular dichroism (NCD) spectra and the corresponding UV/Vis absorption spectra. Under irradiation with UV light, the GdIII‐WV chains show dominant ligand‐based red phosphorescence, with λmax≈660 nm for 1 ‐(SS/RR) and 680 nm for 3 ‐(SRSR/RSRS). The NdIII‐WV chains, 2 ‐(SS/RR) and 4 ‐(SRSR/RSRS), exhibit near‐infrared luminescence with sharp lines at 986, 1066, and 1340 nm derived from intra‐f 4F3/2→4I9/2,11/2,13/2 transitions of the NdIII centers. This emission is realized through efficient ligand‐to‐metal energy transfer from the Pybox derivative to the lanthanide ion. Due to the presence of paramagnetic lanthanide(III) and [WV(CN)8]3? moieties connected by cyanide bridges, 1 ‐(SS/RR) and 3 ‐(SRSR/RSRS) are ferrimagnetic spin chains originating from antiferromagnetic coupling between GdIII (SGd=7/2) and WV (SW=1/2) centers with J 1 ‐(SS)=?0.96(1) cm?1, J 1 ‐(RR)=?0.95(1) cm?1, J 3 ‐(SRSR)=?0.91(1) cm?1, and J 3 ‐(RSRS)=?0.94(1) cm?1. 2 ‐(SS/RR) and 4 ‐(SRSR/RSRS) display ferromagnetic coupling within their NdIII‐NC‐WV linkages. 相似文献
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Dr. Min‐Xia Yao Qi Zheng Kang Qian Prof. Dr. You Song Prof. Dr. Song Gao Prof. Dr. Jing‐Lin Zuo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(1):294-303
By using the node‐and‐spacer approach in suitable solvents, four new heterotrimetallic 1D chain‐like compounds (that is, containing 3d–3d′–4f metal ions), {[Ni(L)Ln(NO3)2(H2O)Fe(Tp*)(CN)3] ? 2 CH3CN ? CH3OH}n (H2L=N,N′‐bis(3‐methoxysalicylidene)‐1,3‐diaminopropane, Tp*=hydridotris(3,5‐dimethylpyrazol‐1‐yl)borate; Ln=Gd ( 1 ), Dy ( 2 ), Tb ( 3 ), Nd ( 4 )), have been synthesized and structurally characterized. All of these compounds are made up of a neutral cyanide‐ and phenolate‐bridged heterotrimetallic chain, with a {? Fe? C?N? Ni(? O? Ln)? N?C? }n repeat unit. Within these chains, each [(Tp*)Fe(CN)3]? entity binds to the NiII ion of the [Ni(L)Ln(NO3)2(H2O)]+ motif through two of its three cyanide groups in a cis mode, whereas each [Ni(L)Ln(NO3)2(H2O)]+ unit is linked to two [(Tp*)Fe(CN)3]? ions through the NiII ion in a trans mode. In the [Ni(L)Ln(NO3)2(H2O)]+ unit, the NiII and LnIII ions are bridged to one other through two phenolic oxygen atoms of the ligand (L). Compounds 1 – 4 are rare examples of 1D cyanide‐ and phenolate‐bridged 3d–3d′–4f helical chain compounds. As expected, strong ferromagnetic interactions are observed between neighboring FeIII and NiII ions through a cyanide bridge and between neighboring NiII and LnIII (except for NdIII) ions through two phenolate bridges. Further magnetic studies show that all of these compounds exhibit single‐chain magnetic behavior. Compound 2 exhibits the highest effective energy barrier (58.2 K) for the reversal of magnetization in 3d/4d/5d–4f heterotrimetallic single‐chain magnets. 相似文献
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A linear tetranuclear 3d–4f Co2Dy2 cluster assembled from a polydentate Schiff base exhibits single‐molecule magnet (SMM) behavior with an anisotropic barrier of 33.8 K. Due to the presence of diamagnetic cobalt(III) ions, the tetranuclear cluster of 1 behaves magnetically like a dinuclear Dy2 system. However, the diamagnetic segment might efficiently minimize undesirable intermolecular magnetic interactions, thereby improving the performance of the SMM behavior of 1 . This discrete complex presents us with a unique opportunity to study the magnetic properties and to probe the dynamics of magnetization in a magnetically isolated Dy2 system. 相似文献
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Kevin Blsing Jrg Harloff Axel Schulz Alrik Stoffers Philip Stoer Alexander Villinger 《Angewandte Chemie (International ed. in English)》2020,59(26):10508-10513
Although pure hydrogen cyanide can spontaneously polymerize or even explode, when initiated by small amounts of bases (e.g. CN?), the reaction of liquid HCN with [WCC]CN (WCC=weakly coordinating cation=Ph4P, Ph3PNPPh3=PNP) was investigated. Depending on the cation, it was possible to extract salts containing the formal dihydrogen tricyanide [CN(HCN)2]? and trihydrogen tetracyanide ions [CN(HCN)3]? from liquid HCN when a fast crystallization was carried out at low temperatures. X‐ray structure elucidation revealed hydrogen‐bridged linear [CN(HCN)2]? and Y‐shaped [CN(HCN)3]? molecular ions in the crystal. Both anions can be considered members of highly labile cyanide‐HCN solvates of the type [CN(HCN)n]? (n=1, 2, 3 …) as well as formal polypseudohalide ions. 相似文献
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Jonas Bresien Dr. Stefan Ellinger Dr. Jörg Harloff Prof. Dr. Axel Schulz Katharina Sievert Alrik Stoffers Dr. Christoph Täschler Dr. Alexander Villinger Dr. Cornelia Zur Täschler 《Angewandte Chemie (International ed. in English)》2015,54(15):4474-4477
The systematic study of the reaction of M[PF6] salts and Me3SiCN led to a synthetic method for the synthesis and isolation of a series of salts containing the unprecedented [PF2(CN)4]? ion in good yields. The reaction temperature, pressure, and stoichiometry were optimized. The crystal structures of M[PF2(CN)4] (M=[nBu4N]+, Ag+, K+, Li+, H5O2+) were determined. X‐ray crystallography showed the exclusive formation of the cis isomer in accord with 31P and 19F solution NMR spectroscopy data. Starting with the K[PF2(CN)4] the room temperature ionic liquid EMIm[PF2(CN)4] was prepared exhibiting a rather low viscosity. 相似文献
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《化学:亚洲杂志》2017,12(5):507-514
Five hexanuclear lanthanide clusters of composition [Ln6(μ4‐O)2(HCOO)2L4(HL′)2(dmf)2] [Ln=Dy ( 1 ), Er ( 2 ), Ho ( 3 ), Tb ( 4 ), Gd ( 5 ); H2L=2‐{[2‐(hydroxymethyl)phenylimino]methyl}‐6‐methoxyphenol; H3L′=3‐{[2‐(hydroxymethyl)phenylimino]methyl}benzene‐1,2‐diol; H3L′ was derived in situ from the H2L ligand] were prepared under solvothermal conditions. The [Ln6] cores of 1 – 5 possess an unprecedented motif, namely, two tetrahedron Ln4 units sharing an edge and two vertices. The six LnIII ions of 1 – 5 are connected through two μ4‐O anions. Magnetic susceptibility studies reveal that complex 1 exhibits frequency dependence of the alternating current susceptibility typical of single‐molecule magnets. Complex 1 possesses a relatively large energy barrier of 85 K among all of the reported Dy6 single‐molecule magnets. 相似文献
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Reversible SC‐SC Transformation involving [4+4] Cycloaddition of Anthracene: A Single‐Ion to Single‐Molecule Magnet and Yellow‐Green to Blue‐White Emission 下载免费PDF全文
Xin‐Da Huang Yan Xu Kun Fan Prof. Dr. Song‐Song Bao Prof. Dr. Mohamedally Kurmoo Prof. Dr. Li‐Min Zheng 《Angewandte Chemie (International ed. in English)》2018,57(28):8577-8581
In search of magneto‐optic materials, the mononuclear compounds LnIII(depma)(NO3)3(hmpa)2 (Ln=Dy, Gd) were synthesized. The anthracene moieties undergo [4+4] dimerization when irradiated at 365 nm without loss of crystallinity. The Dy compound switches from a single‐ion to a single‐molecule magnet with doubling of the spin reversal barrier energy and from yellow‐green to blue‐white emission. The dimerization is reversed by heating at 100 °C or partially on light irradiating at 254 nm. The results suggest that lanthanide phosphonates with anthracene are promising smart materials displaying synergistic magneto‐optic property. 相似文献
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Johannes Landmann Jan A. P. Sprenger Michael Hailmann Vera Bernhardt‐Pitchougina Helge Willner Nikolai Ignat'ev Eduard Bernhardt Maik Finze 《Angewandte Chemie (International ed. in English)》2015,54(38):11259-11264
Diborane(6) dianions with substituents that are bonded to boron via carbon are very reactive and therefore only a few examples are known. Diborane(6) derivatives are the simplest catenated boron compounds with an electron‐precise B–B σ‐bond that are of fundamental interest and of relevance for material applications. The homoleptic hexacyanodiborane(6) dianion [B2(CN)6]2− that is chemically very robust is reported. The dianion is air‐stable and resistant against boiling water and anhydrous hydrogen fluoride. Its salts are thermally highly stable, for example, decomposition of (H3O)2[B2(CN)6] starts at 200 °C. The [B2(CN)6]2− dianion is readily accessible starting from 1) B(CN)32− and an oxidant, 2) [BF(CN)3]− and a reductant, or 3) by the reaction of B(CN)32− with [BHal(CN)3]− (Hal=F, Br). The latter reaction was found to proceed via a triply negatively charged transition state according to an SN2 mechanism. 相似文献
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