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Stable ‐ESiMe3 Complexes of CuI and AgI (E=S,Se) with NHCs: Synthons in Ternary Nanocluster Assembly
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Mahmood Azizpoor Fard Tetyana I. Levchenko Carolyn Cadogan William J. Humenny Prof. Dr. John F. Corrigan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(13):4543-4550
As a part of efforts to prepare new “metallachalcogenolate” precursors and develop their chemistry for the formation of ternary mixed‐metal chalcogenide nanoclusters, two sets of thermally stable, N‐heterocyclic carbene metal–chalcogenolate complexes of the general formula [(IPr)Ag?ESiMe3] (IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene; E=S, 1 ; Se, 2 ) and [(iPr2‐bimy)Cu?ESiMe3]2 (iPr2‐bimy=1,3‐diisopropylbenzimidazolin‐2‐ylidene; E=S, 4 ; Se, 5 ) are reported. These are prepared from the reaction between the corresponding carbene metal acetate, [(IPr)AgOAc] and [(iPr‐bimy)CuOAc] respectively, and E(SiMe3)2 at low temperature. The reaction of [(IPr)Ag?ESiMe3] 1 with mercury(II) acetate affords the heterometallic complex [{(IPr)AgS}2Hg] 3 containing two (IPr)Ag?S? fragments bonded to a central HgII, representing a mixed mercury–silver sulfide complex. The reaction of [(iPr2‐bimy)Cu‐SSiMe3]2, which contains a smaller N‐heterocyclic‐carbene, with mercuric(II) acetate affords the high nuclearity cluster, [(iPr2‐bimy)6Cu10S8Hg3] 6 . The new N‐heterocyclic carbene metal–chalcogenolate complexes 1 , 2 , 4 , 5 and the ternary mixed‐metal chalcogenolate complex 3 and cluster 6 have been characterized by multinuclear NMR spectroscopy (1H and 13C), elemental analysis and single‐crystal X‐ray diffraction. 相似文献
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We have used57Fe Mössbauer spectroscopy carried out on a magnetically aligned powder sample of DyFe10Cr2 to investigate its magnetic structure at low temperatures. Previous susceptibility measurements by Stefanski [1] demonstrated the occurrence of a spin-reorientation in DyFe10Cr2 at 190 K. Subsequent work by Yang et al. [2] confirmed this reorientation, at 175 K, and also demonstrated a second spin-reorientation at 75 K. By invoking the example of the RFe11Ti series of compounds, Yang et al. claimed that the reorientation at 175 K is axis-cone type and the 75 K reorientation is cone-plane type. Our measurements confirm the nature of these reorientations. 相似文献
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J. M. Cadogan Hong-Shuo Li Jian-Min Xu S. X. Dou H. K. Liu 《Hyperfine Interactions》1994,94(1):1921-1927
In our search for new ternary rare-earth (R) iron silicon intermetallic compounds, a novel ternary phase with the chemical formula R3Fe18.5Si3.5 has been identified with the RFeSi ratio in the range of 12–1574–7810–12. We have studied compounds with R=Gd, Tb, Dy, Ho, Er, Tm and Lu. All of the samples, except for R=Lu, form the new ternary phase3–22. X-ray diffraction data suggest that for R=Gd and Tb, the crystal structure is the rhombohedral Th2Zn17-type structure and for R=Dy, Ho, Er and Tm, the hexagonal Th2Ni17-type structure. We suggest that a 1/4 replacement of the R sites by Fe(Si) dumbbells in the CaCu5-type structure leads to the new3–22 phase, which is an ordered version of the TbCu7-type structure.57Fe Mössbauer spectroscopy has been used to determine the hyperfine parameters of the57Fe nuclei in the3–22 compounds. At 295 K, the average hyperfine field of the new3–22 phase ranges from 19.8 T (R=Ho) to 22.2 T (R=Gd). Thermogravimetric analysis (TGA) of these compounds gives Curie temperatures in the range 467 K (Tm)–549 K (Gd). Furthermore, our Mössbauer analysis enables us to investigate the preferential site occupancy shown by Si in these structures. 相似文献
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Aitala EM Amato S Anjos JC Appel JA Ashery D Banerjee S Bediaga I Blaylock G Bracker SB Burchat PR Burnstein RA Carter T Carvalho HS Copty NK Costa I Cremaldi LM Darling C Denisenko K Fernandez A Gagnon P Gerzon S Gobel C Gounder K Halling AM Herrera G Hurvits G James C Kasper PA Kwan S Langs DC Leslie J Lundberg B MayTal-Beck S Meadows B de Mello Neto JR Milburn RH de Miranda JM Napier A Nguyen A d'Oliveira AB O'Shaughnessy K Peng KC Perera LP Purohit MV Quinn B Radeztsky S Rafatian A 《Physical review letters》1996,77(12):2384-2387