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Calabrese M, Pizzi A, Daolio A, Beccaria R, Lo Iacono C, Scheiner S, Resnati G. Osme Bond: Geometric and Energetic Features in the Adducts between OsO 4 and Lewis Bases. Chemistry 2024; 30:e202304240. [PMID: 38258620 DOI: 10.1002/chem.202304240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 01/24/2024]
Abstract
Adducts between OsO4 and Lewis bases exert a role in important oxidation processes such as epoxidation and dihydroxylation. It has been shown that the attractive interaction driving the formation of these adducts is a σ-hole bond involving the metal as the electrophilic species; the term Osme Bond (OmB) was proposed for designating it. Here some new adducts between OsO4 and various bases have been characterized through single crystal x-ray diffraction (XRD) and computational studies (density functional theory, DFT), confirming the existence of a robust correlation between σ-hole interaction energy and deformation of the tetrahedral geometry of OsO4. Also, some adducts formed by RuO4 with nucleophiles were investigated computationally.
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Affiliation(s)
- Miriam Calabrese
- NFMLab-Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, I-20131, Milan, Italy
| | - Andrea Pizzi
- NFMLab-Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, I-20131, Milan, Italy
| | - Andrea Daolio
- NFMLab-Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, I-20131, Milan, Italy
| | - Roberta Beccaria
- NFMLab-Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, I-20131, Milan, Italy
| | - Cristina Lo Iacono
- NFMLab-Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, I-20131, Milan, Italy
| | - Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah, 84322-0300, United States
| | - Giuseppe Resnati
- NFMLab-Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Via L. Mancinelli 7, I-20131, Milan, Italy
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2
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Marchi L, Carlino S, Castellano C, Demartin F, Forni A, Ferretti AM, Ponti A, Pasini A, Rigamonti L. Substituent-Guided Cluster Nuclearity for Tetranuclear Iron(III) Compounds with Flat {Fe4(μ3-O)2} Butterfly Core. Int J Mol Sci 2023; 24:ijms24065808. [PMID: 36982884 PMCID: PMC10057004 DOI: 10.3390/ijms24065808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 03/13/2023] [Accepted: 03/16/2023] [Indexed: 03/22/2023] Open
Abstract
The tetranuclear iron(III) compounds [Fe4(μ3-O)2(μ-LZ)4] (1–3) were obtained by reaction of FeCl3 with the shortened salen-type N2O2 tetradentate Schiff bases N,N’-bis(salicylidene)-o-Z-phenylmethanediamine H2LZ (Z = NO2, Cl and OMe, respectively), where the one-carbon bridge between the two iminic nitrogen donor atoms guide preferentially to the formation of oligonuclear species, and the ortho position of the substituent Z on the central phenyl ring selectively drives towards Fe4 bis-oxido clusters. All compounds show a flat almost-symmetric butterfly-like conformation of the {Fe4(μ3-O)2} core, surrounded by the four Schiff base ligands, as depicted by both the X-ray molecular structures of 1 and 2 and the optimized geometries of all derivatives as obtained by UM06/6-311G(d) DFT calculations. The strength of the antiferromagnetic exchange coupling constants between the iron(III) ions varies among the three derivatives, despite their magnetic cores remain structurally almost unvaried, as well as the coordination of the metal ions, with a distorted octahedral environment for the two-body iron ions, Feb, and a pentacoordination with trigonal bipyramidal geometry for the two-wing iron ions, Few. The different magnetic behavior within the series of examined compounds may be ascribed to the influence of the electronic features of Z on the electron density distribution (EDD) of the central {Fe4(μ3-O)2} core, substantiated by a Quantum Theory of Atoms In Molecules (QTAIM) topological analysis of the EDD, as obtained by UM06 calculations 1–3.
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Affiliation(s)
- Lorenzo Marchi
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy;
| | - Stefano Carlino
- Dipartimento di Chimica, Università degli Studi di Milano, Via C. Golgi 19, 20133 Milano, Italy; (S.C.); (C.C.); (F.D.); (A.P.)
| | - Carlo Castellano
- Dipartimento di Chimica, Università degli Studi di Milano, Via C. Golgi 19, 20133 Milano, Italy; (S.C.); (C.C.); (F.D.); (A.P.)
| | - Francesco Demartin
- Dipartimento di Chimica, Università degli Studi di Milano, Via C. Golgi 19, 20133 Milano, Italy; (S.C.); (C.C.); (F.D.); (A.P.)
| | - Alessandra Forni
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”, Consiglio Nazionale delle Ricerche (SCITEC-CNR), Via C. Golgi 19, 20133 Milano, Italy;
| | - Anna M. Ferretti
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”, Consiglio Nazionale delle Ricerche (SCITEC-CNR), Via G. Fantoli 16/15, 20138 Milano, Italy; (A.M.F.); (A.P.)
| | - Alessandro Ponti
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”, Consiglio Nazionale delle Ricerche (SCITEC-CNR), Via G. Fantoli 16/15, 20138 Milano, Italy; (A.M.F.); (A.P.)
| | - Alessandro Pasini
- Dipartimento di Chimica, Università degli Studi di Milano, Via C. Golgi 19, 20133 Milano, Italy; (S.C.); (C.C.); (F.D.); (A.P.)
| | - Luca Rigamonti
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Via G. Campi 103, 41125 Modena, Italy;
- Dipartimento di Chimica, Università degli Studi di Milano, Via C. Golgi 19, 20133 Milano, Italy; (S.C.); (C.C.); (F.D.); (A.P.)
- Correspondence: ; Tel.: +39-059-205-8646
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3
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Lakbaibi Z, Jaafar A, EL Aatiaoui A, Tabyaoui M. Effect of the explicit solvation of 2-propanol on the Darzens reaction mechanism: A computational study. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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de Souza MA, de Castro KK, Almeida-Neto FW, Bandeira PN, Ferreira MK, Marinho MM, da Rocha MN, de Brito DH, Mendes FRDS, Rodrigues TH, de Oliveira MR, de Menezes JE, Barreto AC, Marinho ES, de Lima-Neto P, dos Santos HS, Teixeira AM. Structural and spectroscopic analysis, ADMET study, and anxiolytic-like effect in adult zebrafish (Danio rerio) of 4′-[(1E,2E)-1-(2-(2′,4′-dinitrophenyl)hydrazone-3-(4-methoxyphenyl)allyl)aniline. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.132064] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Scheiner S. Principles Guiding the Square Bonding Motif Containing a Pair of Chalcogen Bonds between Chalcogenadiazoles. J Phys Chem A 2022; 126:1194-1203. [PMID: 35143197 DOI: 10.1021/acs.jpca.1c10818] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The bonding motif adopted by a dimer of chalcogenadiazole molecules is characterized by a pair of equivalent Ch···N chalcogen bonds. Quantum calculations show that the interaction energy is substantial, varying between 4 kcal/mol for Ch = S and 17 kcal/mol for Te. The interaction is cooperative in that the total bond strength is greater than either chalcogen bond individually. Neither the addition of a phenyl ring nor the addition of a pair of cyano substituents to the diazole ring has much influence on this binding. Removal of one N from the diazole weakens the binding, and addition of two nitrogens has little effect. The largest perturbation arises with three N atoms in each ring, for which the binding energy increases by some 25%. The ring size plays a minor role in most cases, although a near doubling of bond strength occurs if there are two N atoms present on a four-membered ring.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, United States
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Scheiner S, Hunter S. Influence of Substituents in the Benzene Ring on the Halogen Bond of Iodobenzene with Ammonia. Chemphyschem 2022; 23:e202200011. [PMID: 35099849 DOI: 10.1002/cphc.202200011] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 01/30/2022] [Indexed: 11/11/2022]
Abstract
The effects on the CI··N halogen bond between iodobenzene and NH3 of placing various substituents on the phenyl ring are monitored by quantum calculations. Substituents R = N(CH3)2, NH2, CH3, OCH3, COCH3, Cl, F, COH, CN, and NO2 were each placed ortho, meta, and para to the I. The depth of the σ-hole on I is deepened as R became more electron-withdrawing which is reflected in a strengthening of the halogen bond, which varied between 3.3 and 5.5 kcal/mol. In most cases, the ortho placement yields the largest perturbation, followed by meta and then para, but this trend is not universal. Parallel to these substituent effects is a progressive lengthening of the covalent C-I bond. Formation of the halogen bond reduces the NMR chemical shielding of all three nuclei directly involved in the C-I··N interaction. The deshielding of the electron donor N is most closely correlated with the strength of the bond, as is the coupling constant between I and N, so both have potential use as spectroscopic measures of halogen bond strength.
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Affiliation(s)
- Steve Scheiner
- Utah State University, Department of Chemistry and Biochemistry, 0300 Old Main Hill, 84322-0300, Logan, UNITED STATES
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7
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Abstract
A halogen-bonded complex containing a pair of anions can be made more stable than the isolated anions if the Lewis acid is a long carbon chain, fully substituted by CN groups, with an I atom on one end and a COO− group on the other, with Cl− as base.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA
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8
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Three types of noncovalent interactions studied between pyrazine and XF. J Mol Model 2021; 28:15. [PMID: 34961885 DOI: 10.1007/s00894-021-05012-8] [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: 10/15/2021] [Accepted: 12/15/2021] [Indexed: 10/19/2022]
Abstract
Three types noncovalent interactions (type I, II and III) between pyrazine (C4H4N2) and XF (X = F, Cl, Br, and I) have been discovered at the MP2/aug-cc-pVTZ level. TypeI is σ-hole interaction between the positive site on the halogen X of XF and the negative site on one of the pyrazine nitrogens. Type II is counterintuitive σ-hole interaction driven by polarization between the positive site on the halogen X of XF and a portion of the pyrazine ring. Type III is an interaction between the lateral regions of the halogen X of XF and the position of the pyrazine ring. Through comparing the calculated interaction energy, we can know that the type II and type III interactions are weaker than the corresponding type I interactions, and type III interactions are weaker than the corresponding type II interactions in C4H4N2-XF complexes. SAPT analysis shows that the electrostatic energy are the major source of the attraction for the type I (σ-hole) interactions while the type III interactions are mainly dispersion energy. For the type II (counterintuitive σ-hole) interactions in C4H4N2-XF (X = F and Cl) complexes, electrostatic energy are the major source of the attraction, while in C4H4N2-XF (X = Br and I) complexes, the electrostatic term, induction and dispersion play equally important role in the total attractive interaction. NBO analysis, AIM theory, and conceptual DFT are also being utilized.
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Scheiner S. On the Ability of Nitrogen to Serve as an Electron Acceptor in a Pnicogen Bond. J Phys Chem A 2021; 125:10419-10427. [PMID: 34846149 DOI: 10.1021/acs.jpca.1c09213] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Whereas pnicogen atoms like P and As have been shown repeatedly to act as electron acceptors in pnicogen bonds, the same is not true of the more electronegative first-row N atom. Quantum calculations assess whether N can serve in this capacity in such bonds and under what conditions. There is a positive π-hole belt that surrounds the central N atom in the linear arrangement of NNNF, NNN-CN, and NNO, which can engage a NH3 base to form a pnicogen bond with binding energy between 3 and 5 kcal/mol. Within the context of a planar arrangement, the π-hole above the N in NO2OF, N(CN)3, and CF3NO2 is also capable of forming a pnicogen bond, the strongest of which amounts to 11 kcal/mol with NMe3 as base. In their pyramidal geometry, NF3 and N(NO2)3 engage with a base through the σ-hole on the central N, with variable binding energies between 2 and 9 kcal/mol. AIM and NBO provide somewhat different interpretations of the secondary interactions that occur in some of these complexes.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300 United States
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10
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Scheiner S. Maximal occupation by bases of π-hole bands surrounding linear molecules. J Comput Chem 2021; 43:319-330. [PMID: 34859910 DOI: 10.1002/jcc.26792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/22/2021] [Accepted: 11/23/2021] [Indexed: 12/19/2022]
Abstract
Linear molecules such as CO2 contain a positive π-hole ring that surrounds C on the molecule's equator. Quantum calculations examine the question as to how many bases can simultaneously bind to this ring. Linear molecules examined are TO2 , where T = C, Si, Ge, Sn; bases are NCH and NH3 . CO2 engages in the weakest of the tetrel bonds, and can bind up to three NCH and two NH3 . Unlike σ-hole tetrel bonds, Si forms the strongest tetrel bonds, with interaction energies as high as 43 kcal/mol with NH3 . But like GeO2 , SiO2 can sustain only two bases in its equatorial ring. The π-hole ring of SnO2 can engage in up to four tetrel bonds with either NCH or NH3 , even though these bonds are weaker than those with GeO2 or SiO2 . As all of these complexes cast TO2 in the role of multiple electron acceptor, the resulting negative cooperativity makes each successive bond weaker than its predecessor as bases are added, as well as reducing the magnitude of the central molecule's π-hole.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah, USA
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11
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Forni A, Russo R, Rapeti G, Pieraccini S, Sironi M. Exploring Orthogonality between Halogen and Hydrogen Bonding Involving Benzene. Molecules 2021; 26:7126. [PMID: 34885707 PMCID: PMC8659280 DOI: 10.3390/molecules26237126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 11/20/2021] [Accepted: 11/23/2021] [Indexed: 11/16/2022] Open
Abstract
The concept of orthogonality between halogen and hydrogen bonding, brought out by Ho and coworkers some years ago, has become a widely accepted idea within the chemists' community. While the original work was based on a common carbonyl oxygen as acceptor for both interactions, we explore here, by means of M06-2X, M11, ωB97X, and ωB97XD/aug-cc-PVTZ DFT calculations, the interdependence of halogen and hydrogen bonding with a shared π-electron system of benzene. The donor groups (specifically NCBr and H2O) were placed on either or the same side of the ring, according to a double T-shaped or a perpendicular geometry, respectively. The results demonstrate that the two interactions with benzene are not strictly independent on each other, therefore outlining that the orthogonality between halogen and hydrogen bonding, intended as energetical independence between the two interactions, should be carefully evaluated according to the specific acceptor group.
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Affiliation(s)
- Alessandra Forni
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”—CNR, INSTM RU, Via Golgi 19, 20133 Milan, Italy
| | - Rosario Russo
- Department of Chemistry, Università degli Studi di Milano, INSTM RU, Via Golgi 19, 20133 Milano, Italy; (R.R.); (G.R.)
| | - Giacomo Rapeti
- Department of Chemistry, Università degli Studi di Milano, INSTM RU, Via Golgi 19, 20133 Milano, Italy; (R.R.); (G.R.)
| | - Stefano Pieraccini
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”—CNR, INSTM RU, Via Golgi 19, 20133 Milan, Italy
- Department of Chemistry, Università degli Studi di Milano, INSTM RU, Via Golgi 19, 20133 Milano, Italy; (R.R.); (G.R.)
| | - Maurizio Sironi
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”—CNR, INSTM RU, Via Golgi 19, 20133 Milan, Italy
- Department of Chemistry, Università degli Studi di Milano, INSTM RU, Via Golgi 19, 20133 Milano, Italy; (R.R.); (G.R.)
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Abstract
The list of σ-hole bonds is long and growing, encompassing both H-bonds and its closely related halogen, chalcogen, etc., sisters. These bonds rely on the asymmetric distribution of electron density, whose depletion along the extension of a covalent bond leaves a positive region of electrostatic potential from which these bonds derive their name. However, the density distributions of other molecules contain analogous positive regions that lie out of the molecular plane known as π-holes, which are likewise capable of engaging in noncovalent bonds. Quantum calculations are applied to study such π-hole bonds that involve linear molecules, whose positive region is a circular belt surrounding the molecule, rather than the more restricted area of a σ-hole. These bonds are examined in terms of their most fundamental elements arising from the spatial dispositions of their relevant molecular orbitals and the π-holes in both the total electron density and the electrostatic potential to which they lead. Systems examined comprise tetrel, chalcogen, aerogen, and triel bonds, as well as those involving group II elements, with atoms drawn from various rows of the Periodic Table. The π-hole bonds established by linear molecules tend to be weaker than those of comparable planar systems.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA
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13
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Scheiner S. Dissection of the Origin of π-Holes and the Noncovalent Bonds in Which They Engage. J Phys Chem A 2021; 125:6514-6528. [PMID: 34310147 DOI: 10.1021/acs.jpca.1c05431] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Accompanying the rapidly growing list of σ-hole bonds has come the acknowledgment of parallel sorts of noncovalent bonds which owe their stability in large part to a deficiency of electron density in the area above the molecular plane, known as a π-hole. The origins of these π-holes are probed for a wide series of molecules, comprising halogen, chalcogen, pnicogen, tetrel, aerogen, and spodium bonds. Much like in the case of their σ-hole counterparts, formation of the internal covalent π-bond in the Lewis acid molecule pulls density toward the bond midpoint and away from its extremities. This depletion of density above the central atom is amplified by an electron-withdrawing substituent. At the same time, the amplitude of the π*-orbital is enhanced in the region of the density-depleted π-hole, facilitating a better overlap with the nucleophile's lone pair orbital and a stabilizing n → π* charge transfer. The presence of lone pairs on the central atom acts to attenuate the π-hole and shift its position somewhat, resulting in an overall weakening of the π-hole bond. There is a tendency for π-hole bonds to include a higher fraction of induction energy than σ-bonds with proportionately smaller electrostatic and dispersion components, but this distinction is less a product of the σ- or π-character and more a function of the overall bond strength.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, United States
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Abstract
It is well known that the presence of an electron-withdrawing substituent (EWS) placed near the halogen (X) atom on a Lewis acid molecule amplifies the ability of this unit to engage in a halogen bond with a base. Quantum calculations are applied to examine how quickly these effects fade as the EWS is moved further and further from the X atom. Conjugated alkene and alkyne chains of varying lengths with a terminal C-I first facilitate analysis as to how the number of these multiple bonds affects the strength of CI··N XB to NH3. Then, electron-withdrawing F and C≡N substituents are placed on the opposite end of the chain, and their effects on the XB properties are monitored as a function of their distance from I. These same EWSs are added to the ortho, meta, and para positions of aromatic iodobenzene. It is found that the XB grows in strength as more triple bonds are added to the alkyne, but there is little change caused by elongating an alkene. The cyano group has a much stronger effect than does F. While F strengthens the XB, its effects are quickly attenuated as it is moved further from I. The consequences of C≡N substitution are stronger and extend over a longer distance. Placement of an EWS on the phenyl ring diminishes with distance: o > m > p, and the effects of disubstitution are nearly additive. These trends apply not only to energetics but also to geometries, properties of the wave function, σ-hole depth, and NMR shielding.
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Affiliation(s)
- Jordan Lapp
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, United States
| | - Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, United States
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Scheiner S. Relative Strengths of a Pnicogen and a Tetrel Bond and Their Mutual Effects upon One Another. J Phys Chem A 2021; 125:2631-2641. [PMID: 33734698 DOI: 10.1021/acs.jpca.1c01211] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ability of the T and Z atoms of TR3ZR2 to engage in a noncovalent interaction with NH3 is assessed by DFT calculations, where the T atom refers to C, Si, and Ge; Z = As, Sb, and P; and substituents R = H and F. In most instances, the tetrel bond (TB) is both stronger and shorter than the pnicogen bond (ZB). These two bond strengths can be equalized, or preference shifted to the ZB, if F substituents are placed on the Z and H on the T atoms. Employing C as the T atom results in a very weak TB, with the ZB clearly favored energetically. The simultaneous formation of both TB and ZB weakens both, particularly the latter, but both bonds survive intact. Geometric and spectroscopic perturbations of the subunits reflect the two types of noncovalent bonds.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University†Logan, Utah 84322-0300, United States
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Frosch J, Koneczny M, Bannenberg T, Tamm M. Halogen Complexes of Anionic N-Heterocyclic Carbenes. Chemistry 2021; 27:4349-4363. [PMID: 33094865 PMCID: PMC7986712 DOI: 10.1002/chem.202004418] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Indexed: 12/12/2022]
Abstract
The lithium complexes [(WCA-NHC)Li(toluene)] of anionic N-heterocyclic carbenes with a weakly coordinating anionic borate moiety (WCA-NHC) reacted with iodine, bromine, or CCl4 to afford the zwitterionic 2-halogenoimidazolium borates (WCA-NHC)X (X=I, Br, Cl; WCA=B(C6 F5 )3 , B{3,5-C6 H3 (CF3 )2 }3 ; NHC=IDipp=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene, or NHC=IMes=1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene). The iodine derivative (WCA-IDipp)I (WCA=B(C6 F5 )3 ) formed several complexes of the type (WCA-IDipp)I⋅L (L=C6 H5 Cl, C6 H5 Me, CH3 CN, THF, ONMe3 ), revealing its ability to act as an efficient halogen bond donor, which was also exploited for the preparation of hypervalent bis(carbene)iodine(I) complexes of the type [(WCA-IDipp)I(NHC)] and [PPh4 ][(WCA-IDipp)I(WCA-NHC)] (NHC=IDipp, IMes). The corresponding bromine complex [PPh4 ][(WCA-IDipp)2 Br] was isolated as a rare example of a hypervalent (10-Br-2) system. DFT calculations reveal that London dispersion contributes significantly to the stability of the bis(carbene)halogen(I) complexes, and the bonding was further analyzed by quantum theory of atoms in molecules (QTAIM) analysis.
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Affiliation(s)
- Jenni Frosch
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Marvin Koneczny
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Thomas Bannenberg
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
| | - Matthias Tamm
- Institut für Anorganische und Analytische ChemieTechnische Universität BraunschweigHagenring 3038106BraunschweigGermany
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Zarechnaya OM, Anisimov AA, Belov EY, Burakov NI, Kanibolotsky AL, Mikhailov VA. Polycentric binding in complexes of trimethylamine- N-oxide with dihalogens. RSC Adv 2021; 11:6131-6145. [PMID: 35423161 PMCID: PMC8694807 DOI: 10.1039/d0ra08165e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 01/13/2021] [Indexed: 02/01/2023] Open
Abstract
Dihalogens readily interact with trimethylamine-N-oxide under ambient conditions. Accordingly, herein, stable 1 : 1 adducts were obtained in the case of iodine chloride and iodine bromide. The crystal and molecular structure of the trimethylamine-N-oxide-iodine chloride adduct was solved. Furthermore, the geometry and electronic structure of the trimethylamine-N-oxide-dihalogen complexes were studied computationally. Only molecular ensembles were found in the global minimum for the 1 : 1 stoichiometry. The O⋯X-Y halogen bond is the main factor for the thermodynamic stability of these complexes. Arguments for electrostatic interactions as the driving force for this noncovalent interaction were discussed. Also, the equilibrium structures are additionally stabilised by weak C-H⋯X hydrogen bonds. Consequently, formally monodentate ligands are bound in a polycentric manner.
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Affiliation(s)
- Olga M Zarechnaya
- L.M. Litvinenko Institute of Physical Organic and Coal Chemistry R. Luxemburg St., 70 Donetsk Ukraine
| | - Aleksei A Anisimov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences 28 Vavilov St. 119991 Moscow Russia
- D.I. Mendeleev Russian Chemical Technological University 9 Miusskaya Sq. 125047 Moscow Russia
| | - Eugenii Yu Belov
- L.M. Litvinenko Institute of Physical Organic and Coal Chemistry R. Luxemburg St., 70 Donetsk Ukraine
| | - Nikolai I Burakov
- L.M. Litvinenko Institute of Physical Organic and Coal Chemistry R. Luxemburg St., 70 Donetsk Ukraine
| | | | - Vasilii A Mikhailov
- L.M. Litvinenko Institute of Physical Organic and Coal Chemistry R. Luxemburg St., 70 Donetsk Ukraine
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18
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Scheiner S. Comparison of Bifurcated Halogen with Hydrogen Bonds. Molecules 2021; 26:molecules26020350. [PMID: 33445461 PMCID: PMC7827642 DOI: 10.3390/molecules26020350] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 01/30/2023] Open
Abstract
Bifurcated halogen bonds are constructed with FBr and FI as Lewis acids, paired with NH3 and NCH bases. The first type considered places two bases together with a single acid, while the reverse case of two acids sharing a single base constitutes the second type. These bifurcated systems are compared with the analogous H-bonds wherein FH serves as the acid. In most cases, a bifurcated system is energetically inferior to a single linear bond. There is a larger energetic cost to forcing the single σ-hole of an acid to interact with a pair of bases, than the other way around where two acids engage with the lone pair of a single base. In comparison to FBr and FI, the H-bonding FH acid is better able to participate in a bifurcated sharing with two bases. This behavior is traced to the properties of the monomers, in particular the specific shape of the molecular electrostatic potential, the anisotropy of the orbitals of the acid and base that interact directly with one another, and the angular extent of the total electron density of the two molecules.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA
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19
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Malpicci D, Lucenti E, Forni A, Marinotto D, Previtali A, Carlucci L, Mercandelli P, Botta C, Righetto S, Cariati E. Ag( i) and Cu( i) cyclic-triimidazole coordination polymers: revealing different deactivation channels for multiple room temperature phosphorescences. Inorg Chem Front 2021. [DOI: 10.1039/d0qi01377c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The photophysics of isostructural Ag(i) and Cu(i) 1D and 3D coordination polymers based on cyclic triimidazole reveals excitation wavelength-dependent multiple emissions with different radiative paths according to the coordinated metal.
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Affiliation(s)
- Daniele Malpicci
- Department of Chemistry
- Università degli Studi di Milano and INSTM RU
- 20133 Milano
- Italy
| | - Elena Lucenti
- Institute of Sciences and Chemical Technologies “Giulio Natta” (SCITEC) of CNR
- 20133 Milano
- Italy
| | - Alessandra Forni
- Institute of Sciences and Chemical Technologies “Giulio Natta” (SCITEC) of CNR
- 20133 Milano
- Italy
| | - Daniele Marinotto
- Institute of Sciences and Chemical Technologies “Giulio Natta” (SCITEC) of CNR
- 20133 Milano
- Italy
| | - Andrea Previtali
- Department of Chemistry
- Università degli Studi di Milano and INSTM RU
- 20133 Milano
- Italy
- Institute of Sciences and Chemical Technologies “Giulio Natta” (SCITEC) of CNR
| | - Lucia Carlucci
- Department of Chemistry
- Università degli Studi di Milano and INSTM RU
- 20133 Milano
- Italy
| | - Pierluigi Mercandelli
- Department of Chemistry
- Università degli Studi di Milano and INSTM RU
- 20133 Milano
- Italy
| | - Chiara Botta
- Institute of Sciences and Chemical Technologies “Giulio Natta” (SCITEC) of CNR
- 20133 Milano
- Italy
| | - Stefania Righetto
- Department of Chemistry
- Università degli Studi di Milano and INSTM RU
- 20133 Milano
- Italy
| | - Elena Cariati
- Department of Chemistry
- Università degli Studi di Milano and INSTM RU
- 20133 Milano
- Italy
- Institute of Sciences and Chemical Technologies “Giulio Natta” (SCITEC) of CNR
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20
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Scheiner S. Competition between a Tetrel and Halogen Bond to a Common Lewis Acid. J Phys Chem A 2020; 125:308-316. [DOI: 10.1021/acs.jpca.0c10060] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, United States
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21
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Sethio D, Raggi G, Lindh R, Erdélyi M. Halogen Bond of Halonium Ions: Benchmarking DFT Methods for the Description of NMR Chemical Shifts. J Chem Theory Comput 2020; 16:7690-7701. [PMID: 33136388 PMCID: PMC7726912 DOI: 10.1021/acs.jctc.0c00860] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Indexed: 12/20/2022]
Abstract
Because of their anisotropic electron distribution and electron deficiency, halonium ions are unusually strong halogen-bond donors that form strong and directional three-center, four-electron halogen bonds. These halogen bonds have received considerable attention owing to their applicability in supramolecular and synthetic chemistry and have been intensely studied using spectroscopic and crystallographic techniques over the past decade. Their computational treatment faces different challenges to those of conventional weak and neutral halogen bonds. Literature studies have used a variety of wave functions and DFT functionals for prediction of their geometries and NMR chemical shifts, however, without any systematic evaluation of the accuracy of these methods being available. In order to provide guidance for future studies, we present the assessment of the accuracy of 12 common DFT functionals along with the Hartree-Fock (HF) and the second-order Møller-Plesset perturbation theory (MP2) methods, selected from an initial set of 36 prescreened functionals, for the prediction of 1H, 13C, and 15N NMR chemical shifts of [N-X-N]+ halogen-bond complexes, where X = F, Cl, Br, and I. Using a benchmark set of 14 complexes, providing 170 high-quality experimental chemical shifts, we show that the choice of the DFT functional is more important than that of the basis set. The M06 functional in combination with the aug-cc-pVTZ basis set is demonstrated to provide the overall most accurate NMR chemical shifts, whereas LC-ωPBE, ωB97X-D, LC-TPSS, CAM-B3LYP, and B3LYP to show acceptable performance. Our results are expected to provide a guideline to facilitate future developments and applications of the [N-X-N]+ halogen bond.
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Affiliation(s)
- Daniel Sethio
- Department of Chemistry—BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
| | - Gerardo Raggi
- Department of Chemistry—BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
| | - Roland Lindh
- Department of Chemistry—BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
| | - Máté Erdélyi
- Department of Chemistry—BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
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22
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Lu J, Scheiner S. Relationships between Bond Strength and Spectroscopic Quantities in H-Bonds and Related Halogen, Chalcogen, and Pnicogen Bonds. J Phys Chem A 2020; 124:7716-7725. [DOI: 10.1021/acs.jpca.0c05936] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Jia Lu
- Department of Chemistry and Biochemistry, Utah State University , Logan, Utah 84322-0300, United States
| | - Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University , Logan, Utah 84322-0300, United States
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23
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Rodrigues-Oliveira AF, Batista PR, Ducati LC, Correra TC. Analyzing the N–H+…π interactions of protonated tryptophan and phenylalkylamines using QTAIM, NCI, and NBO. Theor Chem Acc 2020. [DOI: 10.1007/s00214-020-02643-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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24
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Abstract
A central pnicogen Z atom (Z = Sb, As) is covalently attached to the O atom of three -O(CH2)nX chains where X represents either an aldehyde or amine group. The chain can fold around so that the basic X group can engage in a noncovalent pnicogen bond with the central Z. The formation of up to three pnicogen bonds is energetically favored. The amine appears to engage in stronger pnicogen bonds than does the aldehyde, and bonds to Sb are favored over As, but there is little dependence on the length of the chain. The formation of each successive pnicogen bond reduces the magnitude of the σ-holes surrounding the Z atom, which tends to weaken the attraction for the basic end of the chain.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, United States
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25
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Structures and energetics of clusters surrounding diatomic anions stabilized by hydrogen, halogen, and other noncovalent bonds. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2019.110590] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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26
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Dortéz S, Fernández-Palacio F, Damián J, Gaiteiro C, Ramos J, Gómez-Sal P, Mosquera MEG. Halogen bonding (HaB) in E–I⋯X–M systems: influence of the halogen donor on the HaB nature. CrystEngComm 2020. [DOI: 10.1039/c9ce01449g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A study on how the covalent character of the halogen bond can be modulated by using different halogen donors.
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Affiliation(s)
- Silvia Dortéz
- Departamento de Química Orgánica y Química Inorgánica
- Instituto de Investigación en Química “Andrés M. del Río” (IQAR) Universidad de Alcalá
- 28871-Alcala de Henares
- Spain
| | - Francisco Fernández-Palacio
- Departamento de Química Orgánica y Química Inorgánica
- Instituto de Investigación en Química “Andrés M. del Río” (IQAR) Universidad de Alcalá
- 28871-Alcala de Henares
- Spain
| | - Jesús Damián
- Departamento de Química Orgánica y Química Inorgánica
- Instituto de Investigación en Química “Andrés M. del Río” (IQAR) Universidad de Alcalá
- 28871-Alcala de Henares
- Spain
| | - Carlos Gaiteiro
- Departamento de Química Orgánica y Química Inorgánica
- Instituto de Investigación en Química “Andrés M. del Río” (IQAR) Universidad de Alcalá
- 28871-Alcala de Henares
- Spain
| | - Javier Ramos
- BIOPHYM
- Department of Macromolecular Physics
- Instituto de Estructura de la Materia
- IEM-CSIC
- Spain
| | - Pilar Gómez-Sal
- Departamento de Química Orgánica y Química Inorgánica
- Instituto de Investigación en Química “Andrés M. del Río” (IQAR) Universidad de Alcalá
- 28871-Alcala de Henares
- Spain
| | - Marta E. G. Mosquera
- Departamento de Química Orgánica y Química Inorgánica
- Instituto de Investigación en Química “Andrés M. del Río” (IQAR) Universidad de Alcalá
- 28871-Alcala de Henares
- Spain
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27
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Scheiner S. The ditetrel bond: noncovalent bond between neutral tetrel atoms. Phys Chem Chem Phys 2020; 22:16606-16614. [DOI: 10.1039/d0cp03068f] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The ability of a tetrel atom to serve in the capacity of electron donor in a σ-hole noncovalent bond is tested by quantum calculations.
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Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry
- Utah State University Logan
- Logan
- USA
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28
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Fehér PP, Purgel M, Lengyel A, Stirling A, Fábián I. The mechanism of monochloramine disproportionation under acidic conditions. Dalton Trans 2019; 48:16713-16721. [PMID: 31670733 DOI: 10.1039/c9dt03789f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Monochloramine is a widely employed agent in water treatment technologies. However, its utilization has some drawbacks like the transformation of the active species into the undesired dichloramine. Although it is more pronounced in acidic solutions, the features of this reaction have still remained largely unexplored in the pH < 4 region. In this study the decomposition of monochloramine is examined under such conditions by using kinetic and computational methods. Fast kinetics measurements have convincingly showed that the disproportion into dicloramine is relatively fast and can be studied without any interference from side reactions. By varying the pH, the deprotonation constant of monochloramine has been determined by UV spectroscopy (Ka = 0.023 ± 0.005 M for I = 1.0 M NaClO4, and T = 25.0 °C). Dichloramine formation via monochloramine disproportion was found to follow second-order kinetics. The computations have provided the reaction mechanism and its free energy profile in accord with the proposed kinetic model. This involves the reaction between the protonated and unprotonated forms of monochloramine, with a rate constant k = 335.3 ± 11.8 M-1 s-1, corresponding to an activation free energy barrier of 14.1 kcal mol-1. The simulations predicted a barrier of 14.9 kcal mol-1 and revealed a key short-lived chlorine-bridged intermediate which yields dichloroamine and ammonium ion through a deprotonation-coupled chlorine shift.
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Affiliation(s)
- Péter Pál Fehér
- Department of Physical Chemistry, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary and Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest H-1117, Hungary.
| | - Mihály Purgel
- Department of Physical Chemistry, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary
| | - Adrienn Lengyel
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary.
| | - András Stirling
- Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, Budapest H-1117, Hungary.
| | - István Fábián
- Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, Debrecen H-4032, Hungary. and MTA-DE Redox and Homogeneous Catalytic Reaction Mechanisms Research Group, Egyetem tér 1, Debrecen, H-4032 Hungary
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29
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Lu J, Scheiner S. Effects of Halogen, Chalcogen, Pnicogen, and Tetrel Bonds on IR and NMR Spectra. Molecules 2019; 24:E2822. [PMID: 31382402 PMCID: PMC6696224 DOI: 10.3390/molecules24152822] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 07/25/2019] [Accepted: 07/31/2019] [Indexed: 11/22/2022] Open
Abstract
Complexes were formed pairing FX, FHY, FH2Z, and FH3T (X = Cl, Br, I; Y = S, Se, Te; Z = P, As, Sb; T = Si, Ge, Sn) with NH3 in order to form an A⋯N noncovalent bond, where A refers to the central atom. Geometries, energetics, atomic charges, and spectroscopic characteristics of these complexes were evaluated via DFT calculations. In all cases, the A-F bond, which is located opposite the base and is responsible for the σ-hole on the A atom, elongates and its stretching frequency undergoes a shift to the red. This shift varies from 42 to 175 cm-1 and is largest for the halogen bonds, followed by chalcogen, tetrel, and then pnicogen. The shift also decreases as the central A atom is enlarged. The NMR chemical shielding of the A atom is increased while that of the F and electron donor N atom are lowered. Unlike the IR frequency shifts, it is the third-row A atoms that undergo the largest change in NMR shielding. The change in shielding of A is highly variable, ranging from negligible for FSnH3 all the way up to 1675 ppm for FBr, while those of the F atom lie in the 55-422 ppm range. Although smaller in magnitude, the changes in the N shielding are still easily detectable, between 7 and 27 ppm.
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Affiliation(s)
- Jia Lu
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA
| | - Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA.
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30
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Scheiner S, Michalczyk M, Zierkiewicz W. Structures of clusters surrounding ions stabilized by hydrogen, halogen, chalcogen, and pnicogen bonds. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2019.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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31
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Differential Binding of Tetrel-Bonding Bipodal Receptors to Monatomic and Polyatomic Anions. Molecules 2019; 24:molecules24020227. [PMID: 30634503 PMCID: PMC6358819 DOI: 10.3390/molecules24020227] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 01/05/2019] [Accepted: 01/05/2019] [Indexed: 11/22/2022] Open
Abstract
Previous work has demonstrated that a bidentate receptor containing a pair of Sn atoms can engage in very strong interactions with halide ions via tetrel bonds. The question that is addressed here concerns the possibility that a receptor of this type might be designed that would preferentially bind a polyatomic over a monatomic anion since the former might better span the distance between the two Sn atoms. The binding of Cl− was thus compared to that of HCOO−, HSO4−, and H2PO4− with a wide variety of bidentate receptors. A pair of SnFH2 groups, as strong tetrel-binding agents, were first added to a phenyl ring in ortho, meta, and para arrangements. These same groups were also added in 1,3 and 1,4 positions of an aliphatic cyclohexyl ring. The tetrel-bonding groups were placed at the termini of (-C≡C-)n (n = 1,2) extending arms so as to further separate the two Sn atoms. Finally, the Sn atoms were incorporated directly into an eight-membered ring, rather than as appendages. The ordering of the binding energetics follows the HCO2− > Cl− > H2PO4− > HSO4− general pattern, with some variations in selected systems. The tetrel bonding is strong enough that in most cases, it engenders internal deformations within the receptors that allow them to engage in bidentate bonding, even for the monatomic chloride, which mutes any effects of a long Sn···Sn distance within the receptor.
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32
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Franchini D, Dapiaggi F, Pieraccini S, Forni A, Sironi M. Halogen bonding in the framework of classical force fields: The case of chlorine. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.09.052] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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33
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Halogen Bonds Formed between Substituted Imidazoliums and N Bases of Varying N-Hybridization. Molecules 2017; 22:molecules22101634. [PMID: 28961202 PMCID: PMC6151534 DOI: 10.3390/molecules22101634] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 09/26/2017] [Accepted: 09/27/2017] [Indexed: 12/16/2022] Open
Abstract
Heterodimers are constructed containing imidazolium and its halogen-substituted derivatives as Lewis acid. N in its sp³, sp² and sp hybridizations is taken as the electron-donating base. The halogen bond is strengthened in the Cl < Br < I order, with the H-bond generally similar in magnitude to the Br-bond. Methyl substitution on the N electron donor enhances the binding energy. Very little perturbation arises if the imidazolium is attached to a phenyl ring. The energetics are not sensitive to the hybridization of the N atom. More regular patterns appear in the individual phenomena. Charge transfer diminishes uniformly on going from amine to imine to nitrile, a pattern that is echoed by the elongation of the C-Z (Z=H, Cl, Br, I) bond in the Lewis acid. These trends are also evident in the Atoms in Molecules topography of the electron density. Molecular electrostatic potentials are not entirely consistent with energetics. Although I of the Lewis acid engages in a stronger bond than does H, it is the potential of the latter which is much more positive. The minimum on the potential of the base is most negative for the nitrile even though acetonitrile does not form the strongest bonds. Placing the systems in dichloromethane solvent reduces the binding energies but leaves intact most of the trends observed in vacuo; the same can be said of ∆G in solution.
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