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DFT electronic structure calculations indicate the existence of oxidation state 10 in the Td structure of PtO42+. 相似文献
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Haoyu S. Yu Donald G. Truhlar 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(31):9150-9152
In a recent paper, Wang et al. found an iridium‐containing compound with a formal oxidation state of 9. 5 This is the highest oxidation state ever found in a stable compound. To learn if this is the highest chemical oxidation state possible, Kohn–Sham density functional theory was used to study various compounds, including PdO42+, PtO42+, PtO3F22+, PtO4OH+, PtO5, and PtO4SH+, in which the metal has an oxidation state of 10. It was found that PtO42+ has a metastable state that is kinetically stable with a barrier height for decomposition of 31 kcal mol−1 and a calculated lifetime of 0.9 years. All other compounds studied would readily decompose to lower oxidation states. 相似文献
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Dr. Łukasz Wolański Mateusz Domański Prof. Wojciech Grochala Dr. Paweł Szarek 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(44):10290-10293
Theoretical calculations utilizing relativistic ZORA Hamiltonian point to the conceivable existence of an IrNO3 molecule in C3v geometry. This minimum is shown to correspond to genuine nonavalent iridium nitride trioxide, which is a neutral analogue of cationic [IrO4]+ species detected recently. Despite the presence of nitride anion, the molecule is protected by substantial barriers exceeding 200 kJ mol−1 against transformations leading, for example, to global minimum (O=)2Ir−NO, which contains metal at a lower formal oxidation state. 相似文献
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Hojin Jeong Dongjae Shin Beom-Sik Kim Junemin Bae Sangyong Shin Chanyeong Choe Prof. Jeong Woo Han Prof. Hyunjoo Lee 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(46):20872-20877
Single-atom catalysts (SACs) have emerged as promising materials in heterogeneous catalysis. Previous studies reported controversial results about the relative level in activity for SACs and nanoparticles (NPs). These works have focused on the effect of metal atom arrangement, without considering the oxidation state of the SACs. Here, we immobilized Pt single atoms on defective ceria and controlled the oxidation state of Pt SACs, from highly oxidized (Pt0: 16.6 at %) to highly metallic states (Pt0: 83.8 at %). The Pt SACs with controlled oxidation states were then employed for oxidation of CO, CH4, or NO, and their activities compared with those of Pt NPs. The highly oxidized Pt SACs presented poorer activities than Pt NPs, whereas metallic Pt SACs showed higher activities. The Pt SAC reduced at 300 °C showed the highest activity for all the oxidations. The Pt SACs with controlled oxidation states revealed a crucial missing link between activity and SACs. 相似文献
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The catalytic performance of Pt-based catalysts for the total oxidation of hydrocarbons was investigated.The activity of supported Pt catalysts(Pt/Al2O3,Pt/ZrO2,Pt/TiO2,and Pt/H-ZSM-5)depends on the metal oxide support.Pt/Al2O3 showed the highest catalytic activity when the catalysts were aged at 750°C for 50 h in air.The activity of Pt/Al2O3 was dependent on the valence state of the Pt surface.Pt/Al2O3 with the Pt surface in the metallic state was more active than with the surface in the cationic state.The surface density of acid and basic sites on the Al2O3 support controlled the valence state of the Pt surface and stability of the Pt particles in the highly dispersed state,respectively. 相似文献
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R. C. Binning Meng‐Sheng Liao Carlos R. Cabrera Yasuyuki Ishikawa Hakim Iddir Renxuan Liu E. S. Smotkin Antonio J. Aldykiewicz Deborah J. Myers 《International journal of quantum chemistry》2000,77(2):589-598
B3LYP and SCF‐Xα calculations have been performed on PtnRu(10−n)CO (n = 6–10) clusters. The work aims to simulate the adsorption of CO on the (111) surface of platinum metal and to examine the electronic effects that arise when some Pt atoms are replaced with Ru. Adsorption energies and Pt C and C O stretching frequencies have been calculated for each cluster. Ru does affect the electronic structure of the clusters, the calculated adsorption energies, and frequencies, the Pt C frequency more than the C O. The donation‐backbonding mechanism that accompanies the shift in CO stretching frequency that occurs when CO adsorbs on platinum does not explain the differences in frequency shift observed in CO on various Pt/Ru surfaces. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 77: 589–598, 2000 相似文献
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Debangsu Sil Amit Kumar Prof. Dr. Sankar Prasad Rath 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(32):11214-11223
A hitherto unknown family of diiron(III)–μ‐fluoro bisporphyrins has been synthesized and structurally characterized. Fluoride abstraction from SbF6? and BF4? resulted in the synthesis of the μ‐fluoro complexes of ethane‐ and ethene‐bridged diiron(III) bisporphyrins. Two such complexes were structurally characterized, which revealed a single fluoro bridge between two iron centers with a remarkably bent Fe‐F‐Fe unit. Although isoelectronic with the μ‐hydroxo complexes, the μ‐fluoro species are quite divergent in terms of the electronic structure and properties. UV/Vis spectroscopy of the μ‐fluoro complex exhibits a large redshift (ca. 18 nm) of the Soret band in comparison to their μ‐hydroxo analog. Combined analysis by single crystal X‐ray structure determination and Mössbauer and 1H NMR spectroscopy revealed the presence of two equivalent iron(III) centers in the μ‐fluoro complexes in both solid and solution phases. In contrast, the iron(III) centers of the μ‐hydroxo complexes are known to be inequivalent. Variable‐temperature magnetic studies show a weak antiferromagnetic interaction between the iron(III) centers of the μ‐fluoro complexes with coupling constants (J) ranging from ?33 to ?40 cm?1. The experimental results were further supported by DFT calculations. 相似文献
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Alexandra E. Bosnidou Prof. Dr. Kilian Muñiz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(60):13654-13664
In contrast to aryliodine(III) compounds, which have matured into a particularly attractive class of oxidants in modern synthesis, the synthetic potential of related alkyliodine(III) derivatives has remained widely underestimated. This is surprising since several unique synthetic possibilities arise directly from the low stability of their central carbon–iodine bond. In this respect, these high-oxidation-state iodine compounds resemble environmentally benign variants of the prominent metal counterparts such as those derived from palladium, nickel and copper. This Concept article summarizes the general reactivity trends in alkyliodine(III) chemistry and discusses selected examples of their strategic use as highly reactive, transient species in organic synthesis and homogeneous catalysis. 相似文献
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Jinrong Yang Dr. Guosheng Shi Dr. Yusong Tu Prof. Haiping Fang 《Angewandte Chemie (International ed. in English)》2014,53(38):10190-10194
Recent experiments have shown the coexistence of both large unoxidized and oxidized regions on graphene oxide (GO), but the underlying mechanism for the formation of the GO atomic structure remains unknown. Now, using density functional calculations, 52 oxidation pathways for local pyrene structures on GO were identified, and a kinetic profile for graphene oxidation with a high correlation between oxidation loci was proposed, which is different from the conventional view, which entails a random distribution of oxidation loci. The high correlation is an essential nature of graphene oxidation processes and can be attributed to three crucial effects: 1) breaking of delocalized π bonds, 2) steric hindrance, and 3) hydrogen‐bond formation. This high correlation leads to the coexistence of both large unoxidized and oxidized regions on GO. Interestingly, even in oxidized regions on GO, some small areas of sp2‐hybridized domains, similar to “islands”, can persist because of steric effects. 相似文献
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Dmitruk A. F. Zarechnaya O. M. Opeida I. A. 《Theoretical and Experimental Chemistry》2003,39(5):283-287
We have carried out an ab initio calculation of the potential surface for the reaction CH3O4H CH2=O + O2 + H2O. We have established the structure of the transition state and studied the dependence of the energy barrier on the size of the basis and whether electron correlation is taken into account. We have studied the electronically excited terms for the participants in this reaction and we have established the mechanism for the formation of chemiluminescence emitters in this reaction. 相似文献
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The geometric and electronic properties of some hydrogenated silicon clusters in the presence of oxygen on the surface have been investigated.The density functional theory with generalized gradient approximation functional was applied in our calculations.By calculating the total energy,the double bond Si=O is shown to be more stable than the bridge bond Si-O-Si for large size oxidized clusters.The results of Mulliken population analysis indicate that a so-called passivation effect is enhanced by oxidization effects.From the energy band structures and density of states,we find that some localized states are induced by the p-orbital of O atom mainly and reduce the energy gaps substantially. 相似文献
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Akinobu Matsumoto Dr. Mitsuharu Suzuki Dr. Hironobu Hayashi Dr. Daiki Kuzuhara Dr. Junpei Yuasa Prof. Dr. Tsuyoshi Kawai Prof. Dr. Naoki Aratani Prof. Dr. Hiroko Yamada 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14462-14466
We prepared perylene dications 1 2+ and 2 2+ by using “capped” perylene derivatives, and for the first time, successfully obtained single crystals of a perylene dication 1 2+ that enabled us to perform its structural analysis. We realized that the substituted aryl groups on perylene control the positions of positive charges, thus the remaining electronic system satisfies Clar's sextet rule toward the highest number of localized sextets. Experimental and theoretical evidence proved that Clar's aromatic π‐sextet rule could be applied even for the dicationic perylenes in a very simple way. 相似文献
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Babil Menjón Dr. Sonia Martínez‐Salvador Dipl.‐Chem. Miguel A. Gómez‐Saso Dr. Juan Forniés Prof. Dr. Larry R. Falvello Prof. Dr. Antonio Martín Dr. Athanassios Tsipis Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(26):6371-6382
Chlorocarbon solvents (solv=CH2Cl2, CHCl3) are suggested to play an active role in the oxidative addition of halogens, X2 (X=Cl, Br, I), to homoleptic d8 perfluoromethyl and ‐phenyl platinum(II ) species [Pt(RF)4]2? (RF=CF3, C6F5). The perfluoromethyl group, CF3, has been found to be considerably less prone to undergo reductive elimination processes, and is, therefore, more suitable for stabilizing organoplatinum(IV ) derivatives (see scheme).
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