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. 2020 Jul 28;5(31):19422–19428. doi: 10.1021/acsomega.0c01321

Density Functional Theoretical Study on the Electronic Structure of Rh2O7+ with Low Oxidation States

Yaping Quan 1, Yanying Zhao 1,*
PMCID: PMC7424573  PMID: 32803035

Abstract

graphic file with name ao0c01321_0006.jpg

Rh2On+ (n = 2–10) species are prepared by the reaction of the laser-ablated rhodium atoms with oxygen; furthermore, they are characterized by employing time-of-flight mass spectroscopy. To reveal the stable electronic structure, in this study, we performed the density functional theory calculations for the possible isomers of Rh2O7+. A total of 29 geometries were obtained including cyclic Rh2O3, cyclic Rh2O2, and ring-opening structures with doublet, quartet, sextet, and octet states. It is noteworthy that no Rh–Rh bond was observed for all the optimized Rh2O7+ isomers including oxides, peroxides, superoxides, and oxygen groups. The optimized geometries were also confirmed to exhibit minimum structural energies by employing harmonic frequency analysis at the same energy level. Generally, two types of oxygen-bridged geometries were discovered with cyclic and pseudo-linear Rh2O7+, which contained one or more than one O2 groups. It is concluded that the cyclic structure comprises a lower energy than that observed in pseudo-linear structures. In addition, Rh2O7+ tends to be unstable when the coordination groups change from O2 to O2– unit. Finally, the localized orbital bonding analysis indicates that Rh has oxidation states of 1 or 2 in cyclic Rh2O7+ structures; this is true even in the presence of O2–, O2–, and O22– groups.

Introduction

Rh is regarded as an important active center, which is widely applied in various syntheses and their catalysis.1−4 In numerous syntheses, it has been used as a catalyst for cyclopropanation,5,6 hydroformylation,7,8 and C–H bond activation;9,10 what is more, it has also been used for manufacturing acetic acid11 and β2-amino acid.12 In particular, Shan et al.13 reported a mononuclear rhodium species, which was anchored on a zeolite or titanium dioxide support suspended in an aqueous solution; they catalyzed the direct conversion of methane to methanol and acetic acid using oxygen and carbon monoxide under mild conditions. Furthermore, they proposed that the conversion of methane to oxygenate occurred via an activation in the presence of O2 on isolated Rh+ cations; this was observed under mild conditions, which led to the production of Rh–CH3. Subsequently, the obtained Rh–CH3 can be functionalized via the insertion of O2 or CO to produce methanol or acetic acid, respectively. The isolated Rh+ species then become available for the next catalytic cycle.

Recently, Rh has been discovered to achieve a significant breakthrough by breaking the C–C bond, which further enhanced the high selectivity of electrocatalysts for the ethanol oxidation reaction (EOR).14−16 The high selectivity of the oxidation of CO was observed to occur for single-atom rhodium, rhodium oxides, and metal-based rhodium oxide nanoparticles.17−20 Moreover, for Rh, the oxygen-covered metallic surface is more active.19 A single atom of rhodium can facilitate the transfer of five oxygen atoms to achieve the oxidation of carbon monoxide by a nine-atom rhodium–aluminum oxide cluster;9 this is a significant breakthrough for single-catalyzed catalysis.20 Rhodium-supported catalysts also exhibited an excellent catalytic performance for the oxidation of methane to syngas.21,22 In particular, the aluminum-supported rhodium oxide ion (RhAl3O4+) can activate all the four C–H bonds of a methane molecule via an important intermediate during the conversion of methane into value-added chemicals.22

Moreover, the dinuclear Rh complexes exhibit an extraordinary activity in the organic catalytic synthetic reaction. Garlets et al.10 accomplished the intermolecular sp3 C–H functionalization by the reaction of silicon-substituted alkanes with aryl diazoacetates; this was achieved by employing the developed dirhodium Rh2(S-TPPTTL)4 catalyst, which resulted in the generation of a diverse array of stereodefined substituted silacycloalkanes with high enantioselectivity and diastereoselectivity. Chen et al.16 have successfully achieved a high selectivity of oxidant-free dehydrogenation coupling between aldehydes and alcohols and between different primary alcohols using a dimeric rhodium(II) catalyst. Therefore, it is a challenging task to prepare and synthesize this kind of dimeric rhodium catalyst. For example, Tunik23 synthesized a dimeric rhodium catalyst [Rh2(CO)4(μ-SC6H4CH3)2], which was formed by the reaction of [Rh6(CO)15(NCMe)] with p-thiocresol [(4-Me)C6H4SH] and played a vital role in hydrodesulfurization (HDS) catalysis. In previous reports, the RhOx (x = 1–4) complexes were prepared by employing the reaction of laser-ablated Rh atoms with O2 in Ar. The Rhx(O2)y complexes were observed, but only Rh(O2) and (O2)Rh(O2) were successfully identified using isotopic infrared spectra and frequency calculations associated with density functional theory (DFT). Moreover, (O2)RhO2 was confirmed as a peroxide with rhodium approaching the +6 oxidation state and (O2)Rh(O2) exhibited the behavior of both disuperoxo and diperoxo species.24 In this study, based on the obtained results of mass spectrometry, the electronic structures and bonding character of binary rhodium–oxygen complexes (Rh2O7+) were investigated using DFT calculations.

Results and Discussions

Figures 1, S1, and S2 show the two types of Rh2O7+ isomers with the lowest spin states in energy optimized at the B3LYP/6-311G*/SDD level. As shown in Figure 2, 29 isomers are included with doublet, quartet, sextet, and octet states. There is a single opening-loop structure, 10 cyclic isomers including 6 five-membered structures and 4 four-membered ring structures, and 18 linear isomers including 6 pseudo-linear structures containing O2 and 12 pseudo-linear structures containing one or two O2–. The results indicate that the energy of the opening ring structure is higher than that of the cyclic ones. The rhodium superoxides exhibit a higher energy than the oxygen coordination structures. For all the calculated structures, doublet ring structure 1 is the most stable in energy.

Figure 1.

Figure 1

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Optimized bond length (in Å) and bond angle (in degree) for the lowest spin states of structures 1–11 at the B3LYP/6-311G*/SDD level.

Figure 2.

Figure 2

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Optimized isomers with different spin states of Rh2O7+ at the B3LYP/6-311G*/SDD level.

For the cyclic structures, we also performed additional accurate single-point energy calculations at the CCSD(T)/B3LYP level. As shown in Figure 3, the most stable structure is the sextet of ring structure 3, which is different from the result obtained at the B3LYP level. As seen in Figures 2 and 3, we found that the five-membered ring structures vary significantly with regard to order and energy; however, the four-membered ring structures alter a little in terms of energy.

Figure 3.

Figure 3

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Optimized cyclic isomers with different spin states of Rh2O7+ at the CCSD(T)//B3LYP/6-311G*/SDD level.

Figure 3 shows the geometries and electronic spin states of 10 cyclic and 1 ring-opening-loop structures, corresponding to the order in Figure 2. The detailed geometric parameter and electronic spin state information of these linear structures have also been shown in Figures S1 and S2 (see in the Supporting Information). The geometric structures and vibrational frequencies of structures 1–11 are organized in Table 1. We obtained six five-membered ring structures, which were basically five nonplanar structures and one planar structure, as shown in Figure S3. Structures 1–6 were formed because of a single cyclic Rh2O3 reaction with two oxygen molecules. The cyclic Rh2O3 unit, similar to the cyclic Co2O3 and Ni2O3,25,26 exhibits a characteristic peroxide bond with lengths of 1.275–1.377 Å and a bridged oxygen bond connected with the Rh–O bond having lengths of 1.819–2.251 Å. Structure 3 is observed to be the ground state of a five-membered ring structure with a 6A state. It exhibits a nearly flat structure with a strong O–O stretching vibration at 1147.5 cm–1, which is indicated by the purple arrow in Figure 4a. Simultaneously, bond order (BO) analysis and atoms in molecules (AIM) analysis also confirmed the peroxide bond between O3 and O8, as seen in Table 2. The vibrational strength of two O2 units is very different. This indicated that their electron density distributions are unequal. As shown in Figure 4b, the electron local function (ELF) value of one oxygen is approximately 0.8 and that of the other is 0.9; these have been clearly indicated in orange and red, respectively. Based on the parameter values in Table 2, we can speculate a noncovalent weak interaction between Rh1 and O7. Moreover, its highest occupied molecular orbital (HOMO)-4 molecular orbital can also prove this, as seen in Figure 4c. Subsequently, we calculated the bonding energy of Rh1 and O7 to be 10.7 kcal·mol–1. Therefore, we can predict the method to form structure 3, which is achieved by the weak absorption of Rh2O5 in the O6–O7 molecule. We also calculated the bonding energies of other structures with a higher symmetry than 3; however, these were observed to be less stable than 3. Finally, the localized orbital bonding analysis (LOBA) results showed that Rh has an oxidation state of 2 in structure 3.

Table 1. Ground Spin States and Vibrational Frequencies (cm–1) for Structures 1–11 on Rh2O7+.

    vibrational frequency (cm–1)
struc. ground state ν [cyclic Rh2O3] ν [η2-(O2)]a ν [η2-O2]b ν [η1-O2]c
3 6A 544.2(10.5), 591.2(8.3) 1147.5(171.5)   1553.9(129.3),1589.8(37.4)
4 2A 539.2(16.4),598.9(22.1), 717.7(8.5) 1092.0(170.5) 1299.9(271.8) 1588.8(19.9)
5 2A″ 524.4(23.4),593.4(24.3), 597.0(15.2), 690.6(90.8) 886.2(41.9) 1328.9(502.3), 1348.3(150.9)  
2 6A 531.7(14.5),592.5(27.7), 698.3(6.1) 1107.6(156.7)   1512.6(199.0),1587.9(27.1)
1 6A 552.5(21.0), 581.2(17.7) 1133.2(144.6)   1481.7(268.9),1566.1(62.2)
6 8A 620.9(8.4), 1226.0(175.6) 1347.2(369.0) 1604.7(12.5)
7 8A 500.5(5.8), 535.9(25.4) 919.6(63.4)   1571.2(37.4)
8 2A 536.1(27.7), 556.7(27.5) 916.1(58) 1344.9(253.4) 1601.7(14)
9 8A 494.8(14.3), 538.3(21.3) 866.7(34.5)   1585.6(32.1), 1613.3(8.6)
10 6A 523.6(20.9), 570.9(24.6), 655.7(13.3) 852.5(31.1) 1329.8(291.1) 1612.4(7.1)
11 6B1   847.6(71) 1294.4(249.7), 1304.2(198.5)  
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a

Peroxide group, indicated as O3–O8 in 1.

b

Superoxide group, indicated as O4–O5 in 2.

c

Oxygen coordinate group, indicated as O4–O5 and O6–O7 in 1.

Figure 4.

Figure 4

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Color-filled ELF map of 3: (a) taking the Rh1–Rh2–O3 as a plane, (b) taking the Rh1–O5–O6 as a plane, and (c) HOMO-4 molecular orbital of structure 3.

Table 2. BO and AIM Analysis on Structure 3.

bond BO ρ(r) ∇2ρ(r) E(r) V(r) ε BD
O8–O3 1.166 0.412 –0.272 –0.395 –0.722 0.0403 –0.959
Rh2–O3 0.524 0.110 0.611 –0.0179 –0.188 0.121 –0.163
Rh1–O8 0.577 0.113 0.567 –0.0198 –0.181 0.0284 –0.175
RCP   0.0192 0.0887 0.000865 –0.0204 –1.271 0.0451
Rh2–O9 1.135 0.159 0.731 –0.0543 –0.291 0.140 –0.342
Rh1–O9 0.848 0.131 0.562 –0.0330 –0.207 0.00827 –0.252
Rh2–O4 0.257 0.0666 0.375 –0.000733 –0.0953 0.0292 –0.0110
Rh1–O7 0.209 0.0479 0.311 0.00374 –0.0703 0.0624 0.0781
O4–O5 1.650 0.533 –0.718 –0.644 –0.0111 0.0187 –1.208
O6–O7 1.683 0.537 –0.758 –0.654 –0.0112 0.00923 –1.218
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Structure 5 is calculated to have an 2A″ ground state with a two side-on bonded planar Cs symmetry, which exhibits a moderate O–O stretching vibration at 886.2 cm–1, as indicated by the purple arrow in Figure 5. Compared with structure 3, two O2 units were observed to alter into two O2– units in structure 5. Therefore, it exhibits a strong antisymmetric O–O stretching mode at 1328.9 cm–1 and a symmetric O–O stretching mode at 1348.3 cm–1. It exhibits an energy of 91 kcal·mol–1, which is higher than that of sextet 3 at the CCSD(T) level. Because of the transformation of one of the O2 units to the O2– unit, structure 4 exhibits a strong superoxide O–O stretching vibration at 1299.9 cm–1 and a moderate O–O stretching vibration at 1092.0 cm–1. The O2– and O2 units are almost perpendicular to the plane of the cyclic Rh2O3 and are observed to coordinate with one rhodium atom. It exhibits an energy of 82 kcal·mol–1, which is higher than that of sextet 3 at the CCSD(T) level. Structure 2 is similar to 4 with a strong O–O stretching vibration at 1107.6 cm–1, but the difference is in the fact that there is no O2– unit in structure 2. It exhibits an energy of 94 kcal·mol–1, which is 12 kcal/mol higher than that of doublet 4 at the CCSD(T) level. Structure 1 has a moderate O–O stretching vibration at 1133.2 cm–1, wherein two oxygen molecules are located at different directions on different Rh atoms relative to the cyclic Rh2O3 plane. Structure 6 is similar to 1; the difference being that one of the O2 units was observed to transform into the O2– unit. Therefore, structure 6 has a strong O–O stretching vibration at 1347.2 cm–1. It exhibits an energy of 101 kcal·mol–1, which is only 5 kcal/mol higher than that of sextet 1 at the CCSD(T) level. Based on the abovementioned results, we can conclude that at the CCSD(T)//B3LYP/6-311G*/SDD level, the energy is observed to increase when the structure contains a superoxide unit and is coordinated to two rhodium atoms. This is in agreement with the B3LYP results. However, the energy is observed to show an opposite behavior when two units are coordinated to one rhodium, which is not in accordance with the B3LYP results.

Figure 5.

Figure 5

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Color-filled ELF map of 5 and 11 (taking the Rh1–Rh2–O3 as a plane).

Ring-opening-loop structure 11 is calculated to have a 6B1 ground state with a planar C2v symmetry. It appears to be a breakdown product of the peroxide bond in the five-membered ring of 5. Its energy is 113 kcal·mol–1, which is 22 kcal/mol higher than that of 5; therefore, it becomes less stable when a cleavage occurs in the peroxide bond. Furthermore, BO analysis and AIM analysis are shown in Table S2. Figure 5 shows the ELF analysis. The results indicate that the O–O bond is actually broken for 3 because of no bond critical point being observed between the peroxide O–O bond. As the most stable structure, structure 5 may be a potential catalyst, which clearly and primarily demonstrates the activity of the cyclic Rh2O3;27 this is achieved because of the weak oxygen coordination.

In addition to the five-membered ring structure, we also discovered four four-membered ring structures. Structures 7–10 are formed via the reaction of the rhombic ring Rh2O2, attaching an extra O atom terminally with two molecular oxygens. The rhombic ring has been observed in numerous transition metal–oxygen systems.25,26,28 The rhombic ring of the Rh2O2 unit has a special terminal Rh–O bond with lengths of 1.678–1.704 Å and a bridged oxygen bond that is connected with the Rh–O bonds of lengths of 1.881–1.941 Å. Structure 7 is found to be the ground state of the four-membered ring structure with the 8A state. It exhibits a nonplanar structure and a strong Rh–O stretching vibration at 919.6 cm–1, with two weak O2 stretching vibrations at 1571.2 cm–1. The LOBA results showed that Rh has an oxidation state of 1 in structure 7. Structure 8 comprises a characteristic superoxide bond with a strong O–O stretching vibration at 1344.9 cm–1 and a moderate Rh–O stretching vibration at 916.1 cm–1. Structure 9 is another isomer of 7, wherein two O2 units are coordinated to two respective rhodium atoms. Therefore, it has a strong Rh–O stretching vibration at 866.7 cm–1. Structure 10 is another isomer of 8. Consequently, it exhibits a strong Rh–O stretching vibration at 852.5 cm–1. For the four-membered ring structures, we can predict that wherever two oxygen molecules are coordinated, the structures containing superoxide bonds are higher in energy than those without them. In addition, the linear structures prove to be the most unstable, as shown in Figures 2 and S4.

Conclusions

In summary, DFT calculations were successful in obtaining 29 isomers of Rh2O7+, including two types of oxygen-bridged bonds with ring and linear structures. In all the structures, the presence of the Rh–Rh bond was not observed. The most stable structure was discovered to be the sextet of structure 3, wherein Rh has an oxidation state of 2. Last but not the least, analytical vibration and AIM analysis provided detailed explanation of these structures. This study provides a guidance to detect these structures in future experimental studies. Furthermore, these structures can also be regarded as valuable species in oxidizing and catalysis agents.

Computational Methods

The optimization of the electronic structure and frequency analysis were performed for Rh2O7+ using DFT calculations implanted in the Gaussian 09 program.29 All calculations utilized the three-parameter hybrid function according to Becke, with additional correlation corrections from Lee, Yang, and Parr (B3LYP).30−32 The 6-311G* basis set was used for the O atom; furthermore, the SDD pseudopotential and the basis set were used for the Rh atom. Hybrid density functional B3LYP has proven to be an accurate method for reproducing transition metal–oxygen complexes.33−36 Moreover, we also carried out the optimization and frequency analysis calculations using two other functionals (BP86 and M06L) and three sets of combination bases (6-311G*/SDD, 6-311G*/Lanl2DZ, and 6-31G*/SDD indicated as (1), (2), and (3) in Figure S5a–c, respectively) to compare the calculated results with experimental Rh2O9+. The B3LYP displays good agreement with the experimental results in Figure S5a. However, the BP86 and M06L functionals gave different structures from the experimental ones, as shown in Figure S5b,c, and even no stable structures were obtained for the M06 functional. Thus, the B3LYP functionals and the larger 6-311G*/SDD basis were selected to attain the relatively accurate energy. The wave functions applied were all stabilized to ensure their stabilities for optimization and frequency analysis. The geometries were fully optimized; the harmonic vibrational frequencies were calculated, and zero-point vibrational energies (ZPVE) were derived using Grimme’s dispersion interaction.37 In addition, for the selected species, the single-point energies of the structures optimized at the B3LYP/6-311G*/SDD level were calculated using the CCSD(T) method with the same basis sets.38 The bonding characteristics were used to describe, analyze, and visualize chemical bonds; these included the ELF distribution, bonding orders, and AIM analysis. The LOBA was utilized to elucidate the oxidation states of Rh using the Multiwfn package.39

Acknowledgments

We gratefully acknowledge financial support from the National Natural Science Foundation of China (grant nos. 21473162 and 21873020). Y.Z. is grateful to the project grants 521 Talents Cultivation of Zhejiang Sci-Tech University. This work was also supported by the Zhejiang Provincial Top Key Academic Discipline of Chemical Engineering and Technology.

Supporting Information Available

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsomega.0c01321.

  • Calculated energies and structures, comparison of experimental and calculated frequencies at different functionals and different basis sets, electronic states and vibrational frequencies for 12–29; and AIM analysis and BO on structures 5 and 11 (PDF)

Author Contributions

Calculation and analysis: Y.Q. and Y.Z.; conception, writing original draft preparation, submission and revision, and funding acquisition and supervision: Y.Z.

The authors declare no competing financial interest.

Supplementary Material

ao0c01321_si_001.pdf (535.3KB, pdf)

References

  1. Hermann G. N.; Unruh M. T.; Jung S. H.; Krings M.; Bolm C. Mechanochemical Rhodium(III)-and Gold(I)-Catalyzed C–H Bond Alkynylations of Indoles under Solventless Conditions in Mixer Mills. Angew. Chem. 2018, 130, 10883–10887. 10.1002/ange.201805778. [DOI] [PubMed] [Google Scholar]
  2. Dinh L. V.; Jurisch M.; Fiedler T.; Gladysz J. A. Recycling and Delivery of Homogenrous Flororous Rhidium Catalysts Using Poly (tetrafluoroethylene): “Catalyst-on-a-Type”. ACS Sustainable Chem. Eng. 2017, 5, 10875–10888. 10.1021/acssuschemeng.7b02770. [DOI] [Google Scholar]
  3. Kaur N. Recent Developments in the Dynthesis of Nitrogen Containing Five-Membered Polyheterocycles Using Rhodium Catalysts. Synth. Commun. 2018, 48, 2457–2474. 10.1080/00397911.2018.1487070. [DOI] [Google Scholar]
  4. Cao Y.; Napoline J. W.; Bacsa J.; Pollet P.; Soper J. D.; Sadighi J. P. Synthesis of an Azaphosphatriptycene and Its Rhodium Carbonyl Complex. Organometallics 2019, 38, 1868–1871. 10.1021/acs.organomet.9b00081. [DOI] [Google Scholar]
  5. Trifonova E. A.; Ankudinov N. M.; Mikhaylov A. A.; Chusov D. A.; Nelyubina Y. V.; Perekalin D. S. A Planar-Chiral Rhodium (III) Catalyst with a Sterically Demanding Cyclopentadienyl Ligand and Its Application in the Enantioselective Synthesis of Dihydroisoquinolones. Angew. Chem., Int. Ed. 2018, 57, 7714–7718. 10.1002/anie.201801703. [DOI] [PubMed] [Google Scholar]
  6. Collins L. R.; Auris S.; Goddard R.; Fürstner A. Chiral Heterobimetallic Bismuth–Rhodium Paddlewheel Catalysts: A Conceptually New Approach to Asymmetric Cyclopropanation. Angew. Chem., Int. Ed. 2019, 58, 3557–3561. 10.1002/anie.201900265. [DOI] [PubMed] [Google Scholar]
  7. Drommi D.; Arena C. G. An Effective Diphosphoramidite Rhodium Catalyst for Selective Hydroformylation of 1-Octene. Catal. Commun. 2018, 115, 36–39. 10.1016/j.catcom.2018.07.004. [DOI] [Google Scholar]
  8. Jongkind L. J.; Elemans J. A. A. W.; Reek J. N. H. Cofactor Controlled Encapsulation of a Rhodium Hydroformylation Catalyst. Angew. Chem., Int. Ed. 2019, 58, 2696–2699. 10.1002/anie.201812610. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Gensch T.; James M. J.; Dalton T.; Glorius F. Increasing Catalyst Efficiency in C–H Activation Catalysis. Angew. Chem., Int. Ed. 2018, 57, 2296–2306. 10.1002/anie.201710377. [DOI] [PubMed] [Google Scholar]
  10. Garlets Z. J.; Hicks E. F.; Fu J.; Voight E. A.; Davies H. M. L. Regio- and Stereoselective Rhodium(II)-Catalyzed C-H Functionalization of Organosilanes by Donor/Acceptor Carbenes Derived from Aryldiazoacetates. Org. Lett. 2019, 21, 4910–4914. 10.1021/acs.orglett.9b01833. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Bae J. W.; Chang T. S.; Kim B. S.; Park J. H.; Nam J. S.. Carbon Nitride Heterogeneous Catalyst Containing Rhodium, Method for Preparing the Same, and Method for Preparing Acetic Acid Using the Same. U.S. Patent 10,124,321 B2, 2018, Nov, 13.
  12. Jian J.-H.; Hsu C.-L.; Syu J.-F.; Kuo T.-S.; Tsai M.-K.; Wu P.-Y.; Wu H.-L. Access to β2-Amino Acids via Enantioselective 1,4-Arylation of β-Nitroacrylates Catalyzed by Chiral Rhodium Catalysts. J. Org. Chem. 2018, 83, 12184–12191. 10.1021/acs.joc.8b00586. [DOI] [PubMed] [Google Scholar]
  13. Shan J.; Li M.; Allard L. F.; Lee S.; Flytzani-Stephanopoulos M. Mild Oxidation of Methane to Methanol or Acetic Acid on Supported Isolated Rhodium Catalysts. Nature 2017, 551, 605–608. 10.1038/nature24640. [DOI] [PubMed] [Google Scholar]
  14. Wang X.; Wang C.; Liu Y.; Xiao J. Acceptorless Dehydrogenation and Aerobic Oxidation of Alcohols with a Reusable Binuclear Rhodium (II) Catalyst in Water. Green Chem. 2016, 18, 4605–4610. 10.1039/c6gc01272h. [DOI] [Google Scholar]
  15. Zhang J.; Ye J.; Fan Q.; Jiang Y.; Zhu Y.; Li H.; Cao Z.; Kuang Q.; Cheng J.; Zheng J.; Xie Z. Cyclic Penta-Twinned Rhodium Nanobranches as Superior Catalysts for Ethanol Electro-Oxidation. J. Am. Chem. Soc. 2018, 140, 11232–11240. 10.1021/jacs.8b03080. [DOI] [PubMed] [Google Scholar]
  16. Cheng J.; Zhu M.; Wang C.; Li J.; Jiang X.; Wei Y.; Tang W.; Xue D.; Xiao J. Chemoselective Dehydrogenative Esterification of Aldehydes and Alcohols with a Dimeric Rhodium(II) Catalyst. Chem. Sci. 2016, 7, 4428–4434. 10.1039/c6sc00145a. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Hülsey M. J.; Zhang B.; Ma Z.; Asakura H.; Do D. A.; Chen W.; Tanaka T.; Zhang P.; Wu Z.; Yan N. In Situ Spectroscopy-Guided Engineering of Rhodium Single-Atom Catalysts for CO Oxidation. Nat. Commun. 2019, 10, 1330–1340. 10.1038/s41467-019-09188-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Ligthart D. A. J. M.; van Santen R. A.; Hensen E. J. M. Supported Rhodium Oxide Nanoparticles as Highly Active CO Oxidation Catalysts. Angew. Chem., Int. Ed. 2011, 50, 5306–5310. 10.1002/anie.201100190. [DOI] [PubMed] [Google Scholar]
  19. Gustafson J.; Balmes O.; Zhang C.; Shipilin M.; Schaefer A.; Hagman B.; Merte L. R.; Martin N. M.; Carlsson P.-A.; Jankowski M.; Crumlin E. J.; Lundgren E. The Role of Oxides in Catalytic CO Oxidation over Rhodium and Pladium. ACS Catal. 2018, 8, 4438–4445. 10.1021/acscatal.8b00498. [DOI] [Google Scholar]
  20. Li X.-N.; Zhang H.-M.; Yuan Z.; He S.-G. A Nine-Atom Rhodium–Aluminum Oxide Cluster Oxidizes Five Carbon Monoxide Molecules. Nat. Commun. 2016, 7, 11404–11410. 10.1038/ncomms11404. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Alvarez-Galvan C.; Melian M.; Ruiz-Matas L.; Eslava J. L.; Navarro R. M.; Ahmadi M.; Cuenya B. R.; Fierro J. L. G. Partial Oxidation of Methane to Syngas Over Nickel-Based Catalysts: Influence of Support Type, Addition of Rhodium, and Preparation Method. Front. Chem. 2019, 7, 104–119. 10.3389/fchem.2019.00104. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Li Y.-K.; Yuan Z.; Zhao Y.-X.; Zhao C.; Liu Q.-Y.; Chen H.; He S.-G. Thermal Methane Conversion to Syngas Mediated by Rh1-Doped Aluminum Oxide Cluster Cations RhAl3O4+. J. Am. Chem. Soc. 2016, 138, 12854–12860. 10.1021/jacs.6b05454. [DOI] [PubMed] [Google Scholar]
  23. Kiriakidou-Kazemifar N. K.; Haukka M.; Pakkanen T. A.; Tunik S. P.; Nordlander E. Formation of Rhodium Carbonyl Thiolate Dimers via Elimination of Dihydrogen; Crystal and Molecular Structure of [Rh2(CO)4(μ-SC6H4CH3)2]. J. Org. Chem. 2001, 623, 65–73. 10.1016/s0022-328x(00)00657-4. [DOI] [Google Scholar]
  24. Citra A.; Andrews L. Reactions of Laser-Ablated Rhodium Atoms with O2. Infrared Spectra and DFT Calculations for RhO, ORhO, (O2)RhO2, Rh2O2, Rh(O2) and (O2)Rh(O2) in Solid Argon. J. Phys. Chem. A 1999, 103, 4845–4854. 10.1021/jp990864a. [DOI] [Google Scholar]
  25. Chertihin G. V.; Citra A.; Andrews L.; Bauschlicher C. W. Reactions of Laser-Ablated Cobalt Atoms with O2. Infrared Spectra of Cobalt Oxides in Solid Argon. J. Phys. Chem. A 1997, 101, 8793–8802. 10.1021/jp972022m. [DOI] [Google Scholar]
  26. Citra A.; Chertihin G. V.; Andrews L.; Neurock M. Reactions of Laser-Ablated Nickel Atoms with Dioxygen. Infrared Spectra and Density Functional Calculations of Nickel Oxides NiO, ONiO, Ni2O2, and Ni2O3, Superoxide NiOO, Peroxide Ni (O2), and Higher Complexes in Solid Argon. J. Phys. Chem. A 1997, 101, 3109–3118. 10.1021/jp970019x. [DOI] [Google Scholar]
  27. Kundu M. K.; Mishra R.; Bhowmik T.; Barman S. Rhodium Metal–Rhodium Oxide (Rh–Rh2O3) Nanostructures with Pt-Like or Better Activity Towards Hydrogen Evolution and Oxidation Reactions (HER, HOR) in Acid and Base: Correlating Its HOR/HER Activity with Hydrogen Binding Energy and Oxophilicity of the Catalyst. J. Phys. Chem. A 2018, 6, 23531–23541. 10.1039/c8ta07028h. [DOI] [Google Scholar]
  28. Chertihin G. V.; Saffel W.; Yustein J. T.; Andrews L.; Neurock M.; Ricca A.; Bauschlicher C. W. Reactions of Laser-Ablated Iron Atoms with Oxygen Molecules in Condensing Argon. Infrared Spectra and Density Functional Calculations of Iron Oxide Product Molecules. J. Phys. Chem. 1996, 100, 5261–5273. 10.1021/jp953198w. [DOI] [Google Scholar]
  29. Frisch M. J.; Trucks G. W.; Schlegel H. B.; Scuseria G. E.; Robb M. A.; Cheeseman J. R.; Scalmani G.; Barone V.; Mennucci B.; Petersson G. A.; et al. Gaussian 09, Revision D.01; Gaussian, Inc.: Wallingford, CT, 2013.
  30. Becke A. D. Density-Functional Thermochemistry. III. The Role of Exact Exchange. J. Chem. Phys. 1993, 98, 5648–5652. 10.1063/1.464913. [DOI] [Google Scholar]
  31. Lee C.; Yang W.; Parr R. G. Development of the Colle-Salvetti Correlation-Energy Formula into a Functional of the Electron Density. Phys. Rev. B: Condens. Matter Mater. Phys. 1988, 37, 785–789. 10.1103/physrevb.37.785. [DOI] [PubMed] [Google Scholar]
  32. McLean A. D.; Chandler G. S. Contracted Gaussian Basis Sets for Molecular Calculations. I. Second Row Atoms, Z=11-18. J. Chem. Phys. 1980, 72, 5639–5648. 10.1063/1.438980. [DOI] [Google Scholar]
  33. Tamulienė J.; Vaišnoras R.; Badenes G.; Balevičius L. M. Stability and Magnetic Properties of Co2Om (m = 1, ..., 7) Clusters. Lith. J. Phys. 2009, 49, 137–143. 10.3952/lithjphys.49210. [DOI] [Google Scholar]
  34. Gong Y.; Zhou M.; Andrews L. Spectroscopic and Theoretical Studies of Transition Metal Oxides and Dioxygen Complexes. Chem. Rev. 2009, 109, 6765–6808. 10.1021/cr900185x. [DOI] [PubMed] [Google Scholar]
  35. Gong Y.; Zhou M. Infrared Spectra of Transition-Metal Dioxide Anions: MO2– (M = Rh, Ir, Pt, Au) in Solid Argon. J. Phys. Chem. A 2009, 113, 4990–4995. 10.1021/jp900974w. [DOI] [PubMed] [Google Scholar]
  36. Su J.; Hu S.; Huang W.; et al. On the oxidation states of metal elements in MO3-(M=V, Nb, Ta, Db, Pr, Gd, Pa) anions. Sci. China: Chem. 2016, 59, 442–451. 10.1007/s11426-015-5481-z. [DOI] [Google Scholar]
  37. Goerigk L.; Hansen A.; Bauer C.; Ehrlich S.; Najibi A.; Grimme S. A Look at the Density Functional Theory Zoo with the Advanced GMTKN55 Database for General Main Group Thermochemistry, Kinetics and Noncovalent Interactions. Phys. Chem. Chem. Phys. 2017, 19, 32184–32215. 10.1039/c7cp04913g. [DOI] [PubMed] [Google Scholar]
  38. Urban M.; Noga J.; Cole S. J.; Bartlett R. J. Towards a Full CCSDT Model for Electron Correlation. J. Chem. Phys. 1985, 83, 4041–4046. 10.1063/1.449067. [DOI] [Google Scholar]
  39. Lu T.; Chen F. Multiwfn: a Multifunctional Wavefunction Analyzer. J. Comput. Chem. 2012, 33, 580–592. 10.1002/jcc.22885. [DOI] [PubMed] [Google Scholar]

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