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Remya GS, Suresh CH. On the ineffectiveness of grubbs-type iron olefin metathesis catalysts: Role of spin-state isomerism and cyclopropanation. Inorganica Chim Acta 2022. [DOI: 10.1016/j.ica.2022.120971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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2
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Anila S, Suresh CH, Schaefer HF. Demarcating Noncovalent and Covalent Bond Territories: Imine-CO 2 Complexes and Cooperative CO 2 Capture. J Phys Chem A 2022; 126:4952-4961. [PMID: 35862882 DOI: 10.1021/acs.jpca.2c03221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chemical bond territory is rich with covalently bonded molecules wherein a strong bond is formed by equal or unequal sharing of a quantum of electrons. The noncovalent version of the bonding scenarios expands the chemical bonding territory to a weak domain wherein the interplay of electrostatic and π-effects, dipole-dipole, dipole-induced dipole, and induced dipole-induced dipole interactions, and hydrophobic effects occur. Here we study both the covalent and noncovalent interactive behavior of cyclic and acyclic imine-based functional molecules (XN) with CO2. All parent XN systems preferred the formation of noncovalent (nc) complex XN···CO2, while more saturated such systems (XN') produced both nc and covalent (c) complexes XN'+-(CO2)-. In all such cases, crossover from an nc to c complex is clearly demarcated with the identification of a transition state (ts). The complexes XN'···CO2 and XN'+-(CO2)- are bond stretch isomers, and they define the weak and strong bonding territories, respectively, while the ts appears as the demarcation point of the two territories. Cluster formation of XN with CO2 reinforces the interaction between them, and all become covalent clusters of general formula (XN+-(CO2)-)n. The positive cooperativity associated with the NH···OC hydrogen bond formation between any two XN'+-(CO2)- units strengthened the N-C coordinate covalent bond and led to massive stabilization of the cluster. For instance, the stabilizing interaction between the XN unit with CO2 is increased from 2-7 kcal/mol range in a monomer complex to 14-31 kcal/mol range for the octamer cluster (XN'+-(CO2)-)8. The cooperativity effect compensates for the large reduction in the entropy of cluster formation. Several imine systems showed the exergonic formation of the cluster and are predicted as potential candidates for CO2 capture and conversion.
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Affiliation(s)
- Sebastian Anila
- Chemical Sciences and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019, Kerala, India.,Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Cherumuttathu H Suresh
- Chemical Sciences and Technology Division, CSIR- National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019, Kerala, India.,Academy of Scientific & Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Henry F Schaefer
- Center for Computational Quantum Chemistry, University of Georgia, 140 Cedar Street, Athens 30602, Georgia, United States
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Shaw TE, Diethrich TJ, Stern CL, Scott BL, Jurca T, Gilbert TM, Sattelberger AP. Synthesis, characterization, X-ray and electronic structures of diethyl ether and 1,2-dimethoxyethane adducts of molybdenum(IV) chloride and tungsten(IV) chloride. Dalton Trans 2022; 51:7856-7863. [PMID: 35531983 DOI: 10.1039/d2dt00787h] [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
The bis(diethyl ether) and 1,2-dimethoxyethane (dme) adducts of molybdenum(IV) chloride and tungsten(IV) chloride are valuable starting materials for a variety of synthetic inorganic and organometallic reactions. Despite the broad utility and extensive use of these 6-coordinate complexes, their syntheses remain unoptimized, and their characterization incomplete after more than three decades. While exploring the ligand exchange behaviour of trans-MoCl4(OEt2)2, we obtained single crystals of this red-orange complex and subsequently compared its structural parameters with those of the recently reported trans-WCl4(OEt2)2. Significantly improved procedures for both MoCl4(dme) and WCl4(dme) were developed, and X-ray diffraction data were obtained and analysed. The magnetic properties of the dme adducts were probed, both with Gouy and SQUID magnetometry measurements. The magnetic moment of WCl4(dme) was smaller than that of MoCl4(dme), an observation that we attribute to the greater spin-orbit coupling of tungsten. Electronic structure studies were also conducted to probe the preferential trans configuration of the diethyl ether adducts and to assign the UV-Vis spectra of the dme adducts.
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Affiliation(s)
- Thomas E Shaw
- Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA. .,Renewable Energy and Chemical Transformations (REACT) Cluster, University of Central Florida, Orlando, FL 32816, USA
| | - Timothy J Diethrich
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
| | - Charlotte L Stern
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - Brian L Scott
- Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Titel Jurca
- Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA. .,Renewable Energy and Chemical Transformations (REACT) Cluster, University of Central Florida, Orlando, FL 32816, USA
| | - Thomas M Gilbert
- Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, USA.
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Nandi A, Tarannam N, Rodrigues Silva D, Fonseca Guerra C, Hamlin TA, Kozuch S. Boron Tunneling in the "Weak" Bond-Stretch Isomerization of N-B Lewis Adducts. Chemphyschem 2021; 22:1857-1862. [PMID: 34245098 DOI: 10.1002/cphc.202100505] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Indexed: 11/08/2022]
Abstract
Some nitrile-boron halide adducts exhibit a double-well potential energy surface with two distinct minima: a "long bond" geometry (LB, a van der Waals interaction mostly based on electrostatics, but including a residual charge transfer component) and a "short bond" structure (SB, a covalent dative bond). This behavior can be considered as a "weak" form of bond stretch isomerism. Our computations reveal that complexes RCN-BX3 (R=CH3 , FCH2 , BrCH2 , and X=Cl, Br) exhibit a fast interconversion from LB to SB geometries even close to the absolute zero thanks to a boron atom tunneling mechanism. The computed half-lives of the meta-stable LB compounds vary between minutes to nanoseconds at cryogenic conditions. Accordingly, we predict that the long bond structures are practically impossible to isolate or characterize, which agrees with previous matrix-isolation experiments.
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Affiliation(s)
- Ashim Nandi
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 841051, Israel
| | - Naziha Tarannam
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 841051, Israel
| | - Daniela Rodrigues Silva
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The, Netherlands.,Departamento de Química, Instituto de Ciências Naturais, Universidade Federal de Lavras, 37200-900, Lavras-MG, Brazil
| | - Célia Fonseca Guerra
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The, Netherlands.,Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The, Netherlands
| | - Trevor A Hamlin
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The, Netherlands
| | - Sebastian Kozuch
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, 841051, Israel
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Shaw TE, LeMagueres P, Sattelberger AP, Jurca T. Crystal structure and Hirshfeld surface analysis of the elusive trichlorobis(diethyl ether)oxomolybdenum(V). ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2020; 76:947-951. [DOI: 10.1107/s2053229620011626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 08/25/2020] [Indexed: 11/10/2022]
Abstract
First reported in 1930, MoCl3O(Et2O)2 is a by-product of the reductive synthesis of MoCl4(OEt2)2 from MoCl5. We report herein the X-ray crystal structure and Hirshfeld surface characteristics of mer-MoCl3O(Et2O)2, or [MoCl3O(C4H10O)2]. The compound crystallizes in the orthorhombic space group P212121. The molybdenyl (Mo=O) bond length is 1.694 (3) Å and the cis- and trans-Mo—O distances are 2.157 (3) and 2.304 (3) Å, respectively. Intermolecular Mo=O...H bonding is present in the lattice, with the shortest distance being 2.572 Å.
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Buzsáki D, Kelemen Z, Nyulászi L. Stretching the P-C Bond. Variations on Carbenes and Phosphanes. J Phys Chem A 2020; 124:2660-2671. [PMID: 32159965 PMCID: PMC7307921 DOI: 10.1021/acs.jpca.0c00641] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 03/10/2020] [Indexed: 11/28/2022]
Abstract
The stability and the structure of adducts formed between four substituted phosphanes (PX3, X:H, F, Cl, and NMe2) and 11 different carbenes have been investigated by DFT calculations. In most cases, the structure of the adducts depends strongly on the stability of the carbene itself, exhibiting a linear correlation with the increasing dissociation energy of the adduct. Carbenes of low stability form phosphorus ylides (F), which can be described as phosphane → carbene adducts supported with some back-bonding. The most stable carbenes, which have high energy lone pair, do not form stable F-type structures but carbene → phosphane adducts (E-type structure), utilizing the low-lying lowest unoccupied molecular orbital (LUMO) of the phosphane (with electronegative substituents), benefiting also from the carbene-pnictogen interaction. Especially noteworthy is the case of PCl3, which has an extremely low energy LUMO in its T-shaped form. Although this PCl3 structure is a transition state of rather high energy, the large stabilization energy of the complex makes this carbene-phosphane adduct stable. Most interestingly, in case of carbenes with medium stability both F- and E-type structures could be optimized, giving rise to bond-stretch isomerism. Likewise, for phosphorus ylides (F), the stability of the adducts G formed from carbenes with hypovalent phosphorus (PX-phosphinidene) is in a linear relationship with the stabilization of the carbene. Adducts of carbenes with hypervalent phosphorus (PX5) are the most stable when X is electronegative, and the carbene is highly nucleophilic.
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Affiliation(s)
- Dániel Buzsáki
- Department
of Inorganic and Analytical Chemistry, Budapest
University of Technology and Economics, Szent Gellért tér 4, H-1111 Budapest, Hungary
| | - Zsolt Kelemen
- Department
of Inorganic and Analytical Chemistry, Budapest
University of Technology and Economics, Szent Gellért tér 4, H-1111 Budapest, Hungary
| | - László Nyulászi
- Department
of Inorganic and Analytical Chemistry, Budapest
University of Technology and Economics, Szent Gellért tér 4, H-1111 Budapest, Hungary
- MTA-BME
Computation Driven Chemistry Research Group, Szent Gellért tér 4, H-1111 Budapest, Hungary
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Homray M, Mondal S, Misra A, Chattaraj PK. Bond stretch isomerism in Be32− driven by the Renner–Teller effect. Phys Chem Chem Phys 2019; 21:7996-8003. [DOI: 10.1039/c9cp00643e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Illustration of bond stretch isomerization of triangular D3h Be32− moieties via the linear D∞h intermediate through the Renner–Teller effect. The reactant, intermediate and products are connected schematically by the C2v transition states; moreover, a connection between the transition states and excited state linear intermediate is depicted.
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Affiliation(s)
- Manoswita Homray
- Department of Chemistry
- University of North Bengal
- Darjeeling
- India
- Department of Chemistry and Center for Theoretical Studies
| | - Sukanta Mondal
- Department of Chemistry and Center for Theoretical Studies
- Indian Institute of Technology Kharagpur
- Kharagpur 721302
- India
- Department of Educational Science
| | - Anirban Misra
- Department of Chemistry
- University of North Bengal
- Darjeeling
- India
| | - P. K. Chattaraj
- Department of Chemistry and Center for Theoretical Studies
- Indian Institute of Technology Kharagpur
- Kharagpur 721302
- India
- Department of Chemistry
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Remya PR, Suresh CH. Theoretical evidence for bond stretch isomerism in Grubbs olefin metathesis. J Comput Chem 2017; 38:1704-1711. [PMID: 28436556 DOI: 10.1002/jcc.24814] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/31/2017] [Accepted: 04/06/2017] [Indexed: 01/13/2023]
Abstract
A comprehensive density functional theory study on the dissociative and associative mechanisms of Grubbs first and second generation olefin metathesis catalysis reveals that ruthenacyclobutane intermediate (RuCB) observed in the Chauvin mechanism is not unique as it can change to a non-metathetic ruthenacyclobutane (RuCB') via the phenomenon of bond stretch isomerism (BSI). RuCB and RuCB' differ mainly in RuCα , RuCβ , and Cα Cβ bond lengths of the metallacycle. RuCB is metathesis active due to the agostic type bonding-assisted simultaneous activation of both Cα Cβ bonds, giving hypercoordinate character to Cβ whereas an absence of such bonding interactions in RuCB' leads to typical CC single bond distances and metathesis inactivity. RuCB and RuCB' are connected by a transition state showing moderate activation barrier. The new mechanistic insights invoking BSI explains the non-preference of associative mechanism and the requirement of bulky ligands in the Grubbs catalyst design. The present study lifts the status of BSI from a concept of largely theoretical interest to a phenomenon of intense importance to describe an eminent catalytic reaction. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Premaja R Remya
- Chemical Sciences and Technology Division, , Academy of Scientific & Innovative Research-AcSIR, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, 695 019, India
| | - Cherumuttathu H Suresh
- Chemical Sciences and Technology Division, , Academy of Scientific & Innovative Research-AcSIR, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram, 695 019, India
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