1
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Lewis Acid Stabilized Diatomic Molecules of Group 14: A Computational Study on [(CO) 4Fe] 2E 2 (E = C, Si, Ge, Sn, Pb). J Phys Chem A 2023; 127:9442-9450. [PMID: 37931177 DOI: 10.1021/acs.jpca.3c04376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
A Lewis base and acid combination has been effectively employed to stabilize and isolate the low-valent group 14 compounds. We report DFT studies on stabilizing low-valent group 14 diatomics as adducts of Lewis acids employing transition metal carbonyl fragment iron tetracarbonyl [Fe(CO)4] as Lewis acid. Computational studies on [(CO)4Fe]2E2, E = C, Si, Ge, Sn, and Pb, predict five plausible isomers on its potential energy surface: linear (E2_L), bent (E2_B), three-membered (E2_T), dibridged (E2_D), and four-membered (E2_F). For the carbon analogue, the lowest energy configuration is linear and has a typical cumulenic structure, while silicon and germanium analogues favor three-membered cyclic isomers. Four-membered cyclic isomers are the most stable for tin and lead analogues.
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2
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Rearrangement of dicarboranyl methyl cation to icosahedral C 3 B 9 H 12 + : An ab initio dynamics view. J Comput Chem 2023; 44:256-260. [PMID: 35612818 DOI: 10.1002/jcc.26880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/16/2022] [Accepted: 03/30/2022] [Indexed: 12/31/2022]
Abstract
Closo-carborane anions are prominent, whereas the cations of the same are less abundant in the literature. As these ions have similar size and are weakly coordinating, the ionic liquids of these two ions could have important applications in many areas of chemistry. In view of limited number of polyhedral carborane cations available, we revisited the rearrangement of dicarboranyl methyl cation (7-CH2 7,9-nido-C2 B9 H10 + ) using ab initio molecular dynamics calculations with metadynamics. Our simulations confirmed the concerted mechanism of the rearrangement. We believe this work will resume the interest in its synthesis and carborane cations in general.
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3
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Computational Insights on Periodicity in Bonding and Lewis Acidity and Basicity of the p‐Block Trispyrazolylborate Complexes. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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4
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Computational Insights on Periodicity in Bonding and Lewis Acidity and Basicity of the p‐Block Trispyrazolylborate Complexes. Eur J Inorg Chem 2022. [DOI: 10.1002/ejic.202200585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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5
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Crystallographic evidence for a continuum and reversal of roles in primary-secondary interactions in antimony Lewis acids: applications in carbonyl activation. Chem Commun (Camb) 2022; 58:11009-11012. [PMID: 36097954 DOI: 10.1039/d2cc04027a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Primary and secondary interactions form the basis of substrate activation in Lewis-acid mediated catalysis, with most substrate activations occurring at the secondary binding site. We explore two series of antimony cations, [(NMe2CH2C6H4)(mesityl)Sb]+ (A) and [(NMe2C6H4)(mesityl)Sb]+ (B), by coordinating ligands with varying nucleophilicity at the position trans to the N-donor. The decreased nucleophilicity of the incoming ligands leads to reversal from a primary bond to a secondary interaction in A, whereas a constrained N-coordination in B diminishes the border between primary and secondary bonding. Investigations on carbonyl olefin metathesis reactions and carbonyl reduction demonstrate increased reactivity of a Lewis acid when the substrate activation occurs at the primary binding site.
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6
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P n Ring Size Dependence on NHC-Induced Ring Contraction Reactions of [CoCp‴(η 4-P 4)], [Ta(CO) 2Cp″(η 4-P 4)], and [FeCp*(η 5-P 5)]: A DFT Study. Inorg Chem 2022; 61:15822-15830. [PMID: 36169982 DOI: 10.1021/acs.inorgchem.2c01418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The facile ring contraction of [CoCp‴(η4-P4)] and [Ta(CO)2Cp″(η4-P4)] to [CoCp‴(η3-P3)][(MeNHC)2P] and [Ta(CO)2Cp″(η3-P3)] [(MeNHC)2P] induced by MeNHC and the absence of the ring contraction of [FeCp*(η5-P5)] under the same conditions are studied by density functional theory (DFT) computations. The latter is estimated to be thermodynamically the least favorable reaction and also has a very high energy barrier. The similar strain energies of P3 and P4 rings and the lower strain energy of the P5 ring play a decisive role in the ring contraction capability of these [TM-cyclo-Pn] complexes. Theoretical approaches involving NBO and IBO analysis have been employed to provide a qualitative picture of the overall reactions. The role of substituents and the nature of transition metals in determining the energetics of these reactions has also been studied and an isolobal perspective on these systems affords a simplified picture.
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7
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Hexagonal Planar [B 6 H 6 ] within a [B 6 H 12 ] Borate Complex: Structure and Bonding of [(Cp*Ti) 2 (μ-ɳ 6 : ɳ 6 -B 6 H 6 )(μ-H) 6 ]. Angew Chem Int Ed Engl 2022; 61:e202208293. [PMID: 35770914 DOI: 10.1002/anie.202208293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Indexed: 11/10/2022]
Abstract
Isolation of planar [B6 H6 ] is a long-awaited goal in boron chemistry. Several attempts in the past to stabilize [B6 H6 ] were unsuccessful due to the domination of polyhedral geometries. Herein, we report the synthesis of a triple-decker sandwich complex of titanium [(Cp*Ti)2 (μ-η6 : η6 -B6 H6 )(μ-H)6 ] (1), which features the first-ever experimentally achieved nearly planar six-membered [B6 H6 ] ring, albeit within a [B6 H12 ] borate. The small deviation from planarity is a direct consequence of the predicted structural pattern of the middle ring in 24 Valence Electron Count (VEC) triple-decker complexes. The large ring size of [B6 H6 ] in 1 brings the metal-metal distance into the bonding range. However, significant electron delocalization from the M-M bonding orbital to the bridging hydrogen and B-B skeleton in the middle decreases its bond strength.
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8
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Hexagonal Planar [B6H6] within a [B6H12] Borate complex; Structure and Bonding of [(Cp*Ti)2(µ‐ɳ6:ɳ6‐B6H6)(µ‐H)6]. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202208293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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10
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An electron counting formula to explain and to predict hydrogenated and metallated borophenes. Chem Commun (Camb) 2022; 58:9882-9885. [DOI: 10.1039/d2cc03218j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A generalized electron counting rule for borophene with varying hole density is formulated based on the graphitic electron count. The electronic requirement explains the preference of hydrogenation in β12 borophene...
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11
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From a Möbius-aromatic interlocked Mn 2B 10H 10 wheel to the metal-doped boranaphthalenes M 2@B 10H 8 and M 2B 5 2D-sheets (M = Mn and Fe): a molecules to materials continuum using DFT studies. Chem Sci 2022; 13:8968-8978. [PMID: 36091213 PMCID: PMC9365082 DOI: 10.1039/d2sc02244c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 06/27/2022] [Indexed: 11/21/2022] Open
Abstract
The design of (1) Möbius aromatic interlocked boron wheel Mn2B10H10, (2) Hückel aromatic boron analogs of naphthalene (M2@B10H8; M = Mn and Fe), and (3) metal boride monolayers (FeB5 and Fe2B5), creating a molecules to materials continuum.
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12
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Orbital Engineering in Chemistry. Isr J Chem 2021. [DOI: 10.1002/ijch.202100114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Metal-Stabilized [B 8 H 8 ] 2- Derivatives with Dodecahedral Structure in the Solid and Solution States: [(Cp 2 MBH 3 ) 2 B 8 H 6 ] (Cp=η 5 -C 5 H 5 ; M=Zr (1-Zr) and Hf (1-Hf)). Chemistry 2021; 27:15634-15637. [PMID: 34435385 DOI: 10.1002/chem.202102832] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Indexed: 11/08/2022]
Abstract
Despite the synthesis and structural characterization of closo-hydroborate dianions, [Bn Hn ]2- (n=6-12) more than 50 years ago, some ambiguity remains about the structure of [B8 H8 ]2- . Although the solid-state structure of [B8 H8 ]2- was established by single-crystal X-ray studies in 1969, fast rearrangements in solution at accessible temperatures prevented its detailed characterization. We therefore stabilized a derivative of [B8 H8 ]2- by using Cp2 MBH3 and structurally characterized two new octaborane analogues, [(Cp2 MBH3 )2 B8 H6 ] (Cp=η5 -C5 H5 ; M=Zr (1-Zr) and Hf (1-Hf)), so that the dynamics of the B8 skeleton were arrested. The solid-state structures of both 1-Zr and 1-Hf comprise a dodecahedron core protected by {Cp2 MBH3 } moieties on both sides of the cluster. Spectroscopic characterization (11 B NMR) validates the intactness of the B8 dodecahedron core in solution as well. Theoretical calculations establish that the two exo-{Cp2 MBH3 } fragments provide structural and electronic structural stability to the B8 core and its intact dodecahedral dianionic nature. Furthermore, we propose isodesmic equations for the formation of higher analogues of the Bn core (n>8) guarded by different group 4 transition metals. Our analysis suggests that, as we move to higher polyhedra (n>10), the formation becomes unfavourable irrespective of metal.
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14
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Abstract
Investigations on the boundaries between the neutral and cationic models of (Mesityl)2EX (E = Sb, Bi and X = Cl-, OTf-) have facilitated reversing the Lewis acidity from bismuth to antimony. We use this concept to demonstrate a higher efficiency of (Mesityl)2SbOTf over (Mesityl)2BiOTf in the catalytic reduction of phosphine oxides to phosphines. The experiments supported with computations described herein will find use in designing new Lewis acids relevant to catalysis.
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15
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Comparison of RNC Coupling and CO Coupling Mediated by Cr-Cr Quintuple Bond and B-B Multiple Bonds: Main Group Metallomimetics. J Phys Chem A 2021; 125:7207-7216. [PMID: 34402622 DOI: 10.1021/acs.jpca.1c05185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A theoretical analysis of reductive coupling of isocyanide and CO mediated by a Cr-Cr quintuple bonded complex and B-B multiple bonded complexes shows how the difference in donor-acceptor capability of isocyanide and CO ligands controls the product distributions. In the case of CO, the Cr-Cr quintuple bonded complex is unable to show C-C coupling due to the high π- back bonding possibility of CO and the reaction follows the singlet potential energy surface throughout, whereas, in the case of isocyanide, less π- back bonding possibility allows the reactions to undergo a spin transition and gives a series of products with different spin multiplicities. Similarly, reactions of B-B multiple bonded complexes with CO and isocyanides are also controlled by donor-acceptor capabilities of ligands, and the C-C coupling takes place by changing the oxidation state of the boron centers from +I to +II, in contrast to the classical main group mediated reactions where stable oxidation states are always preserved. This part of the main group chemistry which is dominated by donor-acceptor bonding interaction is more likely to follow transition metal behavior.
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16
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A Neutral Three‐Membered 2π Aromatic Disilaborirane and the Unique Conversion into a Four‐Membered BSi
2
N‐Ring. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009638] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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A Neutral Three-Membered 2π Aromatic Disilaborirane and the Unique Conversion into a Four-Membered BSi 2 N-Ring. Angew Chem Int Ed Engl 2020; 59:23015-23019. [PMID: 32840959 PMCID: PMC7756765 DOI: 10.1002/anie.202009638] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Indexed: 12/15/2022]
Abstract
We report the design, synthesis, structure, bonding, and reaction of a neutral 2π aromatic three‐membered disilaborirane. The disilaborirane is synthesized by a facile one‐pot reductive dehalogenation of amidinato‐silylene chloride and dibromoarylborane with potassium graphite. Despite the tetravalent arrangement of atoms around silicon, the three‐membered silicon‐boron‐silicon ring is aromatic, as evidenced by NMR spectroscopy, nucleus independent chemical shift calculations, first‐principles electronic structure studies using density functional theory (DFT) and natural bond orbital (NBO) based bonding analysis. Trimethylsilylnitrene, generated in situ, inserts in the Si−Si bond of disilaborirane to obtain a four‐membered heterocycle 1‐aza‐2,3‐disila‐4‐boretidine derivative. Both the heterocycles are fully characterized by X‐ray crystallography.
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18
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Cover Feature: Electrophilic Organobismuth Dication Catalyzes Carbonyl Hydrosilylation (Chem. Eur. J. 56/2020). Chemistry 2020. [DOI: 10.1002/chem.202003348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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Electrophilic Organobismuth Dication Catalyzes Carbonyl Hydrosilylation. Chemistry 2020; 26:12717-12721. [DOI: 10.1002/chem.202002006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Indexed: 12/24/2022]
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20
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trans
-Influence in Heavy Main Group Compounds: A Case Study on Tris(pyrazolyl)borate Bismuth Complexes. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000314] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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21
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DFT Study of C–C and C–N Coupling on a Quintuple-Bonded Cr2 Template: MECP (Minimum Energy Crossing Point) Barriers Control Product Distribution. Organometallics 2020. [DOI: 10.1021/acs.organomet.9b00841] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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22
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Structures and bonding in [L]M(μ-CCR) 2M[L] and [L]M(μ-RC 4R)M[L]: requirements for C-C coupling. Dalton Trans 2020; 49:5157-5166. [PMID: 32236179 DOI: 10.1039/c9dt04748d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A theoretical analysis of [L]M(μ-CCR)2M[L] and [L]M(μ-RC4R)M[L], where M represents the selected elements from the main group, transition metals, lanthanides and actinides, shows how the central (μ-CCR)2 and (μ-RC4R) units reorganize as M traverses across the periodic table. In this context transition metal and actinide complexes are similar in nature, while lanthanide and main group complexes show similarity. The ground state electronic configuration and thus the metal oxidation state control these striking differences. An effective way to stabilize the (iii) oxidation state of thorium in a metallacycle complex is shown for the first time. A strategy is proposed to make a cross-connection between the two sets. The approach used here lends itself to obvious extensions.
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23
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Continuum in H-bond and Other Weak Interactions (X–Z···Y): Shift in X–Z Stretch from Blue Through Zero to Red. J Indian Inst Sci 2019. [DOI: 10.1007/s41745-019-00150-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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24
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Abstract
In search of stable, yet reactive aluminum Lewis acids, we have isolated an organoaluminum cation, [(Me2NC6H4)2Al(C4H8O)2]+, coordinated with two labile tetrahydrofuran ligands. Its catalytic performance in aldehyde dimerization reveals turn-over frequencies reaching up to 6000 h-1, exceeding that of the reported main group catalysts. The cation is further demonstrated to catalyze hydroelementation of ketones. Mechanistic investigations reveal that aldehyde dimerization and ketone hydrosilylation occur through carbonyl activation.
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25
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Special issue on 150 years of the periodic table. J CHEM SCI 2019. [DOI: 10.1007/s12039-019-1714-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Stabilization of Classical [B
2
H
5
]
−
: Structure and Bonding of [(Cp*Ta)
2
(B
2
H
5
)(μ‐H)L
2
] (Cp*=η
5
‐C
5
Me
5
; L=SCH
2
S). Angew Chem Int Ed Engl 2019; 58:17684-17689. [DOI: 10.1002/anie.201911480] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 09/21/2019] [Indexed: 12/21/2022]
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27
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Stabilization of Classical [B
2
H
5
]
−
: Structure and Bonding of [(Cp*Ta)
2
(B
2
H
5
)(μ‐H)L
2
] (Cp*=η
5
‐C
5
Me
5
; L=SCH
2
S). Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201911480] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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28
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Front Cover: A Dicationic Bismuth(III) Lewis Acid: Catalytic Hydrosilylation of Olefins (Eur. J. Inorg. Chem. 28/2019). Eur J Inorg Chem 2019. [DOI: 10.1002/ejic.201900694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Herein, we report the synthesis and characterization of the metal free low valent fluoroborylene [(Me-cAAC)2BF] (1) stabilized by cyclic (alkyl)(amino) carbene (cAAC). The fluoroborylene 1 is obtained by the reductive defluorination of Me-cAAC:BF3 with 2.0 equivalents of KC8 in the presence of 1.0 equivalent of Me-cAAC. Due to its highly electron rich nature, 1 underwent one-electron oxidation with 1.0 equivalent of lithium tetrakis(pentafluorophenyl)borate [LiB(C6F5)4] to form the radical cation [(Me-cAAC)2BF]˙+[B(C6F5)4]- (2). DFT studies suggested that the lone pair of electrons is localized on the boron atom in 1, which explains its unprecedented reactivity. Both compounds 1 and 2 were characterized by X-ray crystallography. The radical cation 2 was studied by EPR spectroscopy.
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32
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Overlap of Radial Dangling Orbitals Controls the Relative Stabilities of Polyhedral B nH n- x Isomers ( n = 5-12, x = 0 to n - 1). Inorg Chem 2019; 58:3627-3634. [PMID: 30810302 DOI: 10.1021/acs.inorgchem.8b02986] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The removal of H atoms from polyhedral boranes results in the formation of dangling radial orbitals with one electron each. If there is a requirement of electrons for skeletal bonding to meet the Wade's rule, these are provided from the exohedral orbitals. Additional electrons occupy a linear combination of the dangling orbitals. Stabilization of these molecular orbitals depends on their overlap. The lateral (sideways) overlap of dangling orbitals decreases with the decreasing cluster size from 12 to 5 boron atoms as the orbitals become more and more splayed out. Thus, as the number of dangling orbitals increases, the destabilization of their combinations increases at a higher rate for smaller polyhedral boranes, leading to flat structures with the removal of a fewer number of hydrogens. Though exohedral orbitals form better overlap in larger polyhedral clusters, the increase of electrons with the removal of H atoms results in occupancy of antibonding skeletal orbitals (beyond Wade's rules) and leads to flat structures. The reverse happens when hydrogens are added to a flat cluster. Substitution of BH by Si does not change structural patterns.
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33
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A theoretical analysis of the structure and properties of B26H30 isomers. Consequences to the laser and semiconductor doping capabilities of large borane clusters. Phys Chem Chem Phys 2019; 21:12916-12923. [DOI: 10.1039/c9cp02371b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The most stable isomer B26H30 with its predicted applications.
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34
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B-B Coupling and B-B Catenation: Computational Study of the Structure and Reactions of Metal-Bis(borylene) Complexes. Chemistry 2018; 24:17844-17851. [PMID: 30303575 DOI: 10.1002/chem.201804599] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 10/06/2018] [Indexed: 11/11/2022]
Abstract
A detailed molecular orbital analysis of the metal-bis(borylene) complex [Fe(CO)3 {B(Dur)B(N(SiMe3 )2 )}] (Dur=2,3,5,6-tetramethylphenyl) (1 a) serves as a focal point of recent developments in this area of chemistry, such as B-B coupling and B-B catenation reactions. There is strong a π delocalization between the Fe(CO)3 and (B-Dur)(B-N(SiMe3 )2 ) units; the short B-B distance in 1 a is due to this π delocalization. The π-donor ligand N(SiMe3 )2 on the boron provides a decisive stability to the complex 1 a. The LUMO of 1 a has B-B σ-bonding character. Hence B-B coupling is facilitated by filling the LUMO. Strong σ-donating ligands, such as PMe3 or PCy3 , induce B-B coupling. Expulsion of one CO from 1 a followed by dimerization leads to [Fe(CO)2 {B(Dur)B(N(SiMe3 )2 )}]2 (3 a) with a short Fe-Fe distance of 2.355 Å. A detailed mechanism for the reaction of 3 a with CO to give the B-B catenation product 2 f is presented. The bonding of all intermediates is compared to their isolobal main-group analogues.
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35
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Synthesis, Structure, Bonding, and Reactivity of Metal Complexes Comprising Diborane(4) and Diborene(2): [{Cp*Mo(CO)
2
}
2
{μ‐η
2
:η
2
‐B
2
H
4
}] and [{Cp*M(CO)
2
}
2
B
2
H
2
M(CO)
4
], M=Mo,W. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201803154] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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36
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Synthesis, Structure, Bonding, and Reactivity of Metal Complexes Comprising Diborane(4) and Diborene(2): [{Cp*Mo(CO)
2
}
2
{μ‐η
2
:η
2
‐B
2
H
4
}] and [{Cp*M(CO)
2
}
2
B
2
H
2
M(CO)
4
], M=Mo,W. Angew Chem Int Ed Engl 2018; 57:8079-8083. [DOI: 10.1002/anie.201803154] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Indexed: 11/08/2022]
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37
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38
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Innenrücktitelbild: Nanoisozymes: Crystal‐Facet‐Dependent Enzyme‐Mimetic Activity of V
2
O
5
Nanomaterials (Angew. Chem. 17/2018). Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201802324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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39
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Inside Back Cover: Nanoisozymes: Crystal‐Facet‐Dependent Enzyme‐Mimetic Activity of V
2
O
5
Nanomaterials (Angew. Chem. Int. Ed. 17/2018). Angew Chem Int Ed Engl 2018. [DOI: 10.1002/anie.201802324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Nanoisozymes: Crystal-Facet-Dependent Enzyme-Mimetic Activity of V 2 O 5 Nanomaterials. Angew Chem Int Ed Engl 2018; 57:4510-4515. [PMID: 29424075 DOI: 10.1002/anie.201800681] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Indexed: 01/30/2023]
Abstract
Nanomaterials with enzyme-like activity (nanozymes) attract significant interest owing to their applications in biomedical research. Particularly, redox nanozymes that exhibit glutathione peroxidase (GPx)-like activity play important roles in cellular signaling by controlling the hydrogen peroxide (H2 O2 ) level. Herein we report, for the first time, that the redox properties and GPx-like activity of V2 O5 nanozyme depends not only on the size and morphology, but also on the crystal facets exposed on the surface within the same crystal system of the nanomaterials. These results suggest that the surface of the nanomaterials can be engineered to fine-tune their redox properties to act as "nanoisozymes" for specific biological applications.
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Nanoisozymes: Crystal-Facet-Dependent Enzyme-Mimetic Activity of V2
O5
Nanomaterials. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201800681] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Halogen bond shortens and strengthens the bridge bond of [1.1.1]propellane and the open form of [2.2.2]propellane. Phys Chem Chem Phys 2018; 20:25792-25798. [DOI: 10.1039/c8cp05125a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The electron scavenger property of halogen bond donors is employed to stabilize the bridge-bond of [1.1.1]propellane and o-[2.2.2]propellane.
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Approaches to Sigma Complexes via Displacement of Agostic Interactions: An Experimental and Theoretical Investigation. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00210] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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A DFT Study on the Stabilization of the B≡B Triple Bond in a Metallaborocycle: Contrasting Electronic Structures of Boron and Carbon Analogues. Chemistry 2017; 23:9746-9751. [DOI: 10.1002/chem.201702422] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Indexed: 11/08/2022]
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The Role of Holes in Borophenes: An Ab Initio Study of Their Structure and Stability with and without Metal Templates. Angew Chem Int Ed Engl 2017; 56:10093-10097. [DOI: 10.1002/anie.201610584] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Indexed: 11/09/2022]
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47
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The Role of Holes in Borophenes: An Ab Initio Study of Their Structure and Stability with and without Metal Templates. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201610584] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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48
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Contrasting Behavior of the Z Bonds in X-Z···Y Weak Interactions: Z = Main Group Elements Versus the Transition Metals. Inorg Chem 2017; 56:1132-1143. [PMID: 28075570 DOI: 10.1021/acs.inorgchem.6b02073] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In contrast to the increasing family of weak intermolecular interactions in main-group compounds (X-Z···Y, Z = main-group elements), an analysis of the Cambridge Structural Database indicates that electron-saturated (18-electron) transition-metal complexes show reluctance toward weak M bond formation (X-M···Y, M = transition metal). In particular, weak M bonds involving electron-saturated (18-electron) complexes of transition metals with partially filled d-orbitals are not found. We propose that the nature of valence electron density distribution in transition-metal complexes is the primary reason for this reluctance. A survey of the interaction of selected electron-saturated transition-metal complexes with electron-rich molecules (Y) demonstrates the following: shielding the possible σ-hole on the metal center by the core electron density in 3d series, and enhanced electronegativity and relativistic effects in 4d and 5d series, hinders the formation of the M bond. A balance in all the destabilizing effects has been found in the 4d series due to its moderate polarizability and primogenic repulsion from inner core d-electrons. A changeover in the donor-acceptor nature of the metal center toward different types of incoming molecules is also unveiled here. The present study confirms the possibility of M bond as a new supramolecular force in designing the crystal structures of electron-saturated transition-metal complexes by invoking extreme ligand conditions.
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A halogen bond route to shorten the ultrashort sextuple bonds in Cr2 and Mo2. Chem Commun (Camb) 2017; 53:8168-8171. [DOI: 10.1039/c7cc04653g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Selective extraction of destabilizing σ-electrons from the sextuple bond of Cr2 and Mo2via σ-hole on a halogen bond donor shortens and strengthens the ultra-short metal–metal bond.
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Exohedral Complexation of B40, C60and Arenes with Transition Metals: A Comparative DFT Study. Chem Asian J 2016; 11:3350-3354. [DOI: 10.1002/asia.201601301] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Indexed: 11/09/2022]
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