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Deak N, Septelean R, Buta L, Moraru IT, Cretoiu IA, Soran A, Nemes G. Novel coordination compounds featuring 9-chloro-9-phosphaalkenylchloro-9-germafluorene ligands. Polyhedron 2022. [DOI: 10.1016/j.poly.2022.115866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Moraru IT, Teleanu F, Silaghi-Dumitrescu L, Nemes G. Offsets between hyperconjugations, p→d donations and Pauli repulsions impact the bonding of E-O-E systems. Case study on elements of Group 14. Phys Chem Chem Phys 2022; 24:13217-13228. [PMID: 35593709 DOI: 10.1039/d2cp00869f] [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
The nature of the E-O chemical bond (E = C, Si, Ge, Sn) is investigated in a wide range of model derivatives, such as oxonium cations, hydrogenated/methylated/fluorinated/chlorinated ethers and acyclic oligomers incorporating the E-O-E moiety. By means of density functional theory (DFT) calculations and natural bond orbital (NBO) techniques, we propose a bonding mechanism that explains the structural contrast between the organic and the inorganic counterparts of all these derivatives: the interplay between stabilizing interactions like LP(O)→σ*(E-X) hyperconjugations and LP(O)→d(E) donations with LP(O)⋯σ(E-X) vicinal Pauli repulsions (X = H, C, O, F, Cl) dictates the equilibrium structures in terms of E-O-E angles and E-O bond lengths. In addition, the present work represents the first study of oxonium ions that describes the structural discrepancies among organic derivatives and their heavier analogues. Another novel outcome for ethers and oligomers is that the two non-equivalent lone pair electrons (LPs) at the oxygen atoms impact in different manners the geometries of such derivatives, i.e. the s/p LP is correlated with the bending behaviour of the E-O-E units, while the pure p LP mainly dictates the short E-O bond distances of inorganic derivatives. Lastly, we evaluate the impact of the number of electronegative substituents, e.g. F, Cl or OEH3 groups, on the bond patterns developed for hydrogenated or methylated ethers.
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Affiliation(s)
- Ionut-Tudor Moraru
- Faculty of Chemistry and Chemical Engineering, Department of Chemistry, Babeş-Bolyai University, 1 M. Kogalniceanu Street, RO-400084 Cluj-Napoca, Romania.
| | - Florin Teleanu
- Faculty of Chemistry and Chemical Engineering, Department of Chemistry, Babeş-Bolyai University, 1 M. Kogalniceanu Street, RO-400084 Cluj-Napoca, Romania.
| | - Luminita Silaghi-Dumitrescu
- Faculty of Chemistry and Chemical Engineering, Department of Chemistry, Babeş-Bolyai University, 1 M. Kogalniceanu Street, RO-400084 Cluj-Napoca, Romania.
| | - Gabriela Nemes
- Faculty of Chemistry and Chemical Engineering, Department of Chemistry, Babeş-Bolyai University, 1 M. Kogalniceanu Street, RO-400084 Cluj-Napoca, Romania.
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Le Coz E, Hammoud J, Roisnel T, Cordier M, Dorcet V, Kahlal S, Carpentier JF, Saillard JY, Sarazin Y. Bonding in Barium Boryloxides, Siloxides, Phenoxides and Silazides: A Comparison with the Lighter Alkaline Earths. Chemistry 2021; 27:11966-11982. [PMID: 34121256 DOI: 10.1002/chem.202101687] [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: 05/12/2021] [Indexed: 11/11/2022]
Abstract
Barium complexes ligated by bulky boryloxides [OBR2 ]- (where R=CH(SiMe3 )2 , 2,4,6-i Pr3 -C6 H2 or 2,4,6-(CF3 )3 -C6 H2 ), siloxide [OSi(SiMe3 )3 ]- , and/or phenoxide [O-2,6-Ph2 -C6 H3 ]- , have been prepared. A diversity of coordination patterns is observed in the solid state for both homoleptic and heteroleptic complexes, with coordination numbers ranging between 2 and 4. The identity of the bridging ligand in heteroleptic dimers [Ba(μ2 -X1 )(X2 )]2 depends largely on the given pair of ligands X1 and X2 . Experimentally, the propensity to fill the bridging position increases according to [OB{CH(SiMe3 )2 }2 )]- <[N(SiMe3 )2 ]- <[OSi(SiMe3 )3 ]- <[O(2,6-Ph2 -C6 H3 )]- <[OB(2,4,6-i Pr3 -C6 H2 )2 ]- . This trend is the overall expression of 3 properties: steric constraints, electronic density and σ- and π-donating capability of the negatively charged atom, and ability to generate Ba ⋅ ⋅ ⋅ F, Ba ⋅ ⋅ ⋅ C(π) or Ba ⋅ ⋅ ⋅ H-C secondary interactions. The comparison of the structural motifs in the complexes [Ae{μ2 -N(SiMe3 )2 }(OB{CH(SiMe3 )2 }2 )]2 (Ae = Mg, Ca, Sr and Ba) suggest that these observations may be extended to all alkaline earths. DFT calculations highlight the largely prevailing ionic character of ligand-Ae bonding in all compounds. The ionic character of the Ae-ligand bond encourages bridging coordination, whereas the number of bridging ligands is controlled by steric factors. DFT computations also indicate that in [Ba(μ2 -X1 )(X2 )]2 heteroleptic dimers, ligand predilection for bridging vs. terminal positions is dictated by the ability to establish secondary interactions between the metals and the ligands.
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Affiliation(s)
- Erwann Le Coz
- Univ Rennes, CNRS ISCR, Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000, Rennes, France
| | - Joanna Hammoud
- Univ Rennes, CNRS ISCR, Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000, Rennes, France
| | - Thierry Roisnel
- Univ Rennes, CNRS ISCR, Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000, Rennes, France
| | - Marie Cordier
- Univ Rennes, CNRS ISCR, Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000, Rennes, France
| | - Vincent Dorcet
- Univ Rennes, CNRS ISCR, Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000, Rennes, France
| | - Samia Kahlal
- Univ Rennes, CNRS ISCR, Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000, Rennes, France
| | - Jean-François Carpentier
- Univ Rennes, CNRS ISCR, Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000, Rennes, France
| | - Jean-Yves Saillard
- Univ Rennes, CNRS ISCR, Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000, Rennes, France
| | - Yann Sarazin
- Univ Rennes, CNRS ISCR, Institut des Sciences Chimiques de Rennes)-UMR 6226, 35000, Rennes, France
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