Donor‐unsupported Phosphanylmethanides Li[CH2PR2] (R = tBu, Ph) – Crystal Structure of Li[CH2PtBu2] Solved by XRPD and DFT‐D Calculations

Fink, Lothar; Samigullin, Kamil; Alig, Edith; Lerner, Hans‐Wolfram

doi:10.1002/zaac.201500811

Cited by 8 publications

(4 citation statements)

References 34 publications

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“…For both phosphine oxide 5 and selenide 6 , an alternative synthesis route was employed. First, di- tert -butylchlorosilane ( 1 ) was reacted with freshly prepared LiCH 2 P( t Bu) 2 , followed by oxidation of the phosphorus(III) intermediate either with oxygen resulting in compound 5 or using gray selenium to afford compound 6 . The two products were obtained in moderate ( 5 : 26%) and good ( 6 : 71%) yields over two steps.…”

Section: Resultsmentioning

confidence: 99%

“…n -Butyllithium (2.5 or 1.6 M solution in hexane, Merck KGaA), tert -butyllithium (1.6 M solution in pentane, Merck KGaA), di- tert- butylchlorosilane (97%, Merck KGaA), di- tert -butylmethylphosphine (97%, Merck KGaA), trichlorosilane (99%, Merck KGaA), 1,3,5-trimethoxybenzene (≥99%, Merck KGaA), and sulfur (99%, Merck KGaA) were used as received without further purification. (Di- tert -butylphosphanyl)methyllithium, , di- tert -butylmethylphosphine sulfide, tris(pentafluorophenyl)borane, and tritylium tetrakis(pentafluorophenyl)borate were synthesized according to reported literature procedures. C 6 D 6 , CD 2 Cl 2 , and 1,2-dichlorobenzene (1,2-C 6 H 4 Cl 2 ) used for NMR spectroscopy were dried over 3 Å molecular sieves and degassed by a standard freeze–pump–thaw procedure.…”

Section: Methodsmentioning

confidence: 99%

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Structural and Electronic Effects on Phosphine Chalcogenide Stabilized Silicon Centers in Four-Membered Heterocyclic Cations

Falk

Bauer

2022

Inorg. Chem.

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Understanding the interplay of structural and electronic parameters in the stabilization of Lewis acidic silicon centers is crucial for stereochemical questions and applications in bond activation and catalytic transformations. Phosphine chalcogenide functionalized (Ch = O, S, and Se) hydrosilanes having tert-butyl and 2,4,6-trimethoxyphenyl (TMP) substituents on the silicon atom were synthesized, and the ring-closing reactions to afford the heterocyclic four-membered CPChSi cations were investigated. Synthetic access was only achieved for the sulfur-and selenium-based cations. A thorough study by means of single-crystal X-ray structure determination, NMR spectroscopic data, and density functional theory (DFT) calculations provided insight into important electronic and structural parameters affecting the stability of the intramolecularly stabilized cations. Detailed structural considerations were made on the contributions to the ring strain (angular strain and steric repulsion). Thermochemical investigations showed that the substituents on the silicon and phosphorus atoms play an important role for the stability of the cationic heterocycles. In the absence of large steric repulsions through bulky substituents (methyl groups on silicon and tert-butyl groups on phosphorus), an intrinsic stability sequence of the intramolecular Ch−Si coordination depending on the chalcogen atom in the direction Se ≤ S < O can be observed. However, the order is reversed (O < S < Se) in the case of strong repulsions between sterically demanding substituents (tert-butyl groups on both silicon and phosphorus atoms). Natural bond orbital (NBO) analysis supported the explanations for the observed deshielding trends in 31 P NMR spectroscopy and revealed that the O−Si bond is more ionic in nature compared to the S−Si and Se−Si bonds, with the latter exhibiting higher covalent character due to a more efficient charge transfer through a σ-type n Ch → p Si interaction.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Structural and Electronic Effects on Phosphine Chalcogenide Stabilized Silicon Centers in Four-Membered Heterocyclic Cations

Falk

Bauer

2022

Inorg. Chem.

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“…Dichloromethane, pentane, tetrahydrofuran (THF), and toluene were dried and degassed with an MBraun SP800 solvent purification system. tert ‐Butylchlorophenylsilane ( 1 ), [5b] (di‐ tert ‐butylphosphanyl)methyllithium, [5b,9] and tris(pentafluorophenyl)borane [10] were synthesized according to reported literature procedures. Red selenium was kindly provided by the Scheer group.…”

Section: Methodsmentioning

confidence: 99%

A Cyclic Phosphonium Ion with an Asymmetrically Substituted Selenide‐Stabilized Silicon Center: Synthesis, Structure, and Substituent Effects

Fontana

Bauer

2023

ChemistrySelect

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A new heterocyclic four-membered CPSeSi cation was synthesized in its racemic form by B(C 6 F 5 ) 3 -mediated ring-closing reaction starting from the hydrosilane precursor. The cation has an asymmetrically substituted silicon center, which is stabilized by a selenium-silicon bond. The phosphonium hydroborate and its precursor were characterized by single-crystal X-ray diffraction analysis and NMR spectroscopy. 77 Se, 31 P, and 29 Si NMR spectroscopic parameters proved to be sensitive probes for determining small electronic changes around the silylium-type center. Density functional theory (DFT) calculations of the ring-opening energy of the selenium-based cation gave insight into the stability of the Se-Si bond and revealed a stronger intramolecular stabilization of the silicon atom compared to a coordinating phosphane sulfide function. For the first time, the influence of a C 6 F 5 group at the silicon atom of these type of cations was also investigated, showing a slightly increased stabilization of the Se-Si linkage in the cyclic selenium-based cation.

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“…A remarkably high number of these structures were determined from X-ray powder diffraction (XRPD) data, due to their polymeric structure and insolubility in hydrocarbons. MeLi (Me = methyl), − PhLi (Ph = phenyl), indenylLi, Licp (cp = cyclopentadienyl), and Licp* (cp* = 1,2,3,4,5 pentamethylcyclopentadienyl) were determined from synchrotron data, whereas mesitylLi and Li[CH 2 P( t Bu) 2 ] ( t Bu = tert -butyl) were determined from laboratory data.…”

Section: Introductionmentioning

confidence: 99%

Syntheses and Crystal Structures of Phenyl-Lithium Derivatives

et al. 2018

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Although organolithium compounds have been studied and applied for ∼100 years, only few crystal structures of pure, unsolvated organolithium compounds have been reported so far. Therefore, several phenyl-lithium derivatives were synthesized by lithium-halogen exchange reactions, yielding fairly soluble polymers in the cases of 4- and 2-methylphenyl-lithium ( p-TolLi and o-TolLi). Their crystal structures have been determined by X-ray powder diffraction. Remarkably, o-TolLi crystallizes in the noncentrosymmetric space group P222 with two independent monomers, whereas the crystal structure of p-TolLi is described in spacegroup P2/ a. In contrast, no polymer of 5- m-XyLi (3,5-dimethyl-phenyl-lithium) could be observed, but single crystals of a [(5- m-XyLi)(MTBE)LiBr] adduct were isolated (MTBE = methyl- tert-butylether). This gives hints on the nature of lithium-halogen exchange reactions. Steric and electronic effects of the phenyl-lithium substitution are further discussed in conjunction with related compounds.

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Donor‐unsupported Phosphanylmethanides Li[CH₂PR₂] (R = tBu, Ph) – Crystal Structure of Li[CH₂PtBu₂] Solved by XRPD and DFT‐D Calculations

Cited by 8 publications

References 34 publications

Structural and Electronic Effects on Phosphine Chalcogenide Stabilized Silicon Centers in Four-Membered Heterocyclic Cations

Structural and Electronic Effects on Phosphine Chalcogenide Stabilized Silicon Centers in Four-Membered Heterocyclic Cations

A Cyclic Phosphonium Ion with an Asymmetrically Substituted Selenide‐Stabilized Silicon Center: Synthesis, Structure, and Substituent Effects

Syntheses and Crystal Structures of Phenyl-Lithium Derivatives

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