Reactivity Studies of Heteroleptic Silylenes with N₂O

Reaction of heteroleptic silylenes LSiX (L = PhC­(N<i>t</i>Bu)₂; X = PPh₂ (<b>1</b>), NPh₂ (<b>2</b>), NMe₂ (<b>3</b>), O<i>t</i>Bu (<b>4</b>)) with N₂O resulted in the oxidized dimeric product [LSi­(X)­(μ-O)]₂ (X = PPh₂ (<b>5</b>), NPh₂ (<b>6</b>), NMe₂ (<b>7</b>), O<i>t</i>Bu (<b>8</b>)), which contains a four-membered Si₂O₂ ring. Compounds <b>5</b>–<b>8</b> were characterized by spectroscopic and spectrometric techniques. The molecular structures of <b>5</b>–<b>8</b> were established by single-crystal X-ray structure analysis

Reactivity of Stable Heteroleptic Silylene PhC(N<i>t</i>Bu)₂SiNPh₂ toward Diazobenzene and <i>N</i>‑Benzylidineaniline

The reaction of heteroleptic silylene LSiNPh₂ [L = PhC­(N<i>t</i>Bu)₂] with diazobenzene afforded product <b>6</b>. This involves one <i>o</i>-C–H bond activation at one of the phenyl groups of diazobenzene and migration of this hydrogen atom from the phenyl ring to one of the nitrogen atoms, which leads to the formation of the new C–Si and N–Si bonds. The reaction of benzylidineaniline with LSiNPh₂ results in the oxidative addition of the three-membered silaaziridine derivative <b>7</b>. Compounds <b>6</b> and <b>7</b> were fully characterized by elemental analysis, multinuclear NMR spectroscopy, and EI-MS spectrometry. The molecular structures of compounds <b>6</b> and <b>7</b> were established unequivocally by single-crystal X-ray structural analysis

Reactivity Studies of Heteroleptic Silylenes with N₂O

Reaction of heteroleptic silylenes LSiX (L = PhC­(N<i>t</i>Bu)₂; X = PPh₂ (<b>1</b>), NPh₂ (<b>2</b>), NMe₂ (<b>3</b>), O<i>t</i>Bu (<b>4</b>)) with N₂O resulted in the oxidized dimeric product [LSi­(X)­(μ-O)]₂ (X = PPh₂ (<b>5</b>), NPh₂ (<b>6</b>), NMe₂ (<b>7</b>), O<i>t</i>Bu (<b>8</b>)), which contains a four-membered Si₂O₂ ring. Compounds <b>5</b>–<b>8</b> were characterized by spectroscopic and spectrometric techniques. The molecular structures of <b>5</b>–<b>8</b> were established by single-crystal X-ray structure analysis

Facile Access to the Functionalized N-Donor Stabilized Silylenes PhC(N<i>t</i>Bu)₂SiX (X = PPh₂, NPh₂, NCy₂, N<i>i</i>Pr₂, NMe₂, N(SiMe₃)₂, O<i>t</i>Bu)

Reactions of silylenes with organic substrates generally lead to silicon­(IV) compounds. Ligand substitution at the silicon­(II) atom of silylene, without changing the formal +2 oxidation state, is very rare. We report herein a straightforward route to functionalized silylenes LSiX (L = PhC­(N<i>t</i>Bu)₂ and X = PPh₂ (<b>1</b>), NPh₂ (<b>2</b>), NCy₂(<b>3</b>), N<i>i</i>Pr₂ (<b>4</b>), NMe₂ (<b>5</b>), N­(SiMe₃)₂ (<b>6</b>), O<i>t</i>Bu (<b>7</b>)). Silylenes <b>1</b>–<b>7</b> have been prepared in quantitative yield by a modified ligand exchange reaction of PhC­(N<i>t</i>Bu)₂SiCl (LSiCl) with the corresponding lithium or potassium salts. Compounds <b>1</b>–<b>7</b> were characterized by spectroscopic and spectrometric techniques. Single-crystal X-ray structures of <b>1</b>, <b>3</b>, and <b>4</b> were determined

Facile Access to the Functionalized N-Donor Stabilized Silylenes PhC(N<i>t</i>Bu)₂SiX (X = PPh₂, NPh₂, NCy₂, N<i>i</i>Pr₂, NMe₂, N(SiMe₃)₂, O<i>t</i>Bu)

Reactions of silylenes with organic substrates generally lead to silicon­(IV) compounds. Ligand substitution at the silicon­(II) atom of silylene, without changing the formal +2 oxidation state, is very rare. We report herein a straightforward route to functionalized silylenes LSiX (L = PhC­(N<i>t</i>Bu)₂ and X = PPh₂ (<b>1</b>), NPh₂ (<b>2</b>), NCy₂(<b>3</b>), N<i>i</i>Pr₂ (<b>4</b>), NMe₂ (<b>5</b>), N­(SiMe₃)₂ (<b>6</b>), O<i>t</i>Bu (<b>7</b>)). Silylenes <b>1</b>–<b>7</b> have been prepared in quantitative yield by a modified ligand exchange reaction of PhC­(N<i>t</i>Bu)₂SiCl (LSiCl) with the corresponding lithium or potassium salts. Compounds <b>1</b>–<b>7</b> were characterized by spectroscopic and spectrometric techniques. Single-crystal X-ray structures of <b>1</b>, <b>3</b>, and <b>4</b> were determined

Stabilization of Low Valent Silicon Fluorides in the Coordination Sphere of Transition Metals

Silicon­(II) fluoride is unstable; therefore, isolation of the stable species is highly challenging and was not successful during the last 45 years. SiF₂ is generally generated in the gas phase at very high temperatures (∼1100–1200 °C) and low pressures and readily disproportionates or polymerizes. We accomplished the syntheses of stable silicon­(II) fluoride species by coordination of silicon­(II) to transition metal carbonyls. Silicon­(II) fluoride compounds L­(F)­Si·M­(CO)₅ {M = Cr (<b>4</b>), Mo (<b>5</b>), W­(<b>6</b>)} (L = PhC­(N<i>t</i>Bu)₂) were prepared by metathesis reaction from the corresponding chloride with Me₃SnF. However, the chloride derivatives L­(Cl)­Si·M­(CO)₅ {M = Cr (<b>1</b>), Mo (<b>2</b>), W­(<b>3</b>)} (L = PhC­(N<i>t</i>Bu)₂) were prepared by the treatment of transition metal carbonyls with L­(Cl)­Si. Direct fluorination of L­(Cl)Si with Me₃SnF resulted in oxidative addition products. Compounds <b>4</b>–<b>6</b> are stable at ambient temperature under an inert atmosphere of nitrogen. Compounds <b>4</b>–<b>6</b> were characterized by NMR spectroscopy, EI-MS spectrometry, and elemental analysis. The molecular structures of <b>4</b> and <b>6</b> were unambiguously established by single-crystal X-ray diffraction. Compounds <b>4</b> and <b>6</b> are the first structurally characterized fluorides, after the discovery of SiF₂ about four and a half decades ago

Reactivity Studies of Heteroleptic Silylenes PhC(N<i>t</i>Bu)₂SiX (X = NPh₂, NMe₂) toward Selected Azides

The reaction of LSiX (L = PhC­(N<i>t</i>Bu)₂, X = NPh₂ (<b>1</b>), NMe₂ (<b>2</b>)) with trimethylsilyl azide (<b>3</b>) resulted in silaimines [LSi­(<i></i>NSiMe₃)­X] (X = NPh₂ (<b>5</b>), NMe₂ (<b>7</b>)). Similarly the reaction of <b>1</b> and <b>2</b> with adamantyl azide (<b>4</b>) yielded [LSi­(<i></i>NAd)­X] (X = NPh₂ (<b>6</b>), NMe₂ (<b>8</b>), Ad = adamantyl) compounds. Silaimines <b>5</b>–<b>8</b> contain tetracoordinate silicon atoms. Compounds <b>6</b> and <b>8</b> are the first tetracoordinate silicon compounds having the terminal SiNAd unit. All compounds were characterized by spectroscopic and spectrometric techniques. The molecular structures of <b>5</b>, <b>6</b>, and <b>8</b> were unequivocally established by single-crystal X-ray structure analysis

Reactivity Studies of a Stable N‑Heterocyclic Silylene with Triphenylsilanol and Pentafluorophenol

The reaction of the stable N-heterocyclic silylene [CH­{(CCH₂)­(CMe)­(2,6-<i>i</i>Pr₂C₆H₃N)₂}­Si] (<b>1</b>) with triphenylsilanol and pentafluorophenol in a 1:2 molar ratio resulted in quantitative yields of the pentacoordinate silicon-containing compounds [CH­{(CMe)₂(2,6-<i>i</i>Pr₂C₆H₃N)₂}­Si­(H)­{OSiPh₃}₂] (<b>2</b>) and [CH­{(CMe)₂(2,6-<i>i</i>Pr₂C₆H₃N)₂}­Si­(H)­{OC₆F₅}₂] (<b>3</b>), respectively. Compounds <b>2</b> and <b>3</b> were formed by O–H bond activation of triphenylsilanol and pentafluorophenol. They were characterized by elemental analysis, NMR spectroscopy, and EI-MS spectrometry. In their solid-state structures the silicon atom is tetracoordinate in <b>2</b>, whereas it is pentacoordinate in <b>3</b>

Facile Access to the Functionalized N-Donor Stabilized Silylenes PhC(N<i>t</i>Bu)₂SiX (X = PPh₂, NPh₂, NCy₂, N<i>i</i>Pr₂, NMe₂, N(SiMe₃)₂, O<i>t</i>Bu)

Reactions of silylenes with organic substrates generally lead to silicon­(IV) compounds. Ligand substitution at the silicon­(II) atom of silylene, without changing the formal +2 oxidation state, is very rare. We report herein a straightforward route to functionalized silylenes LSiX (L = PhC­(N<i>t</i>Bu)₂ and X = PPh₂ (<b>1</b>), NPh₂ (<b>2</b>), NCy₂(<b>3</b>), N<i>i</i>Pr₂ (<b>4</b>), NMe₂ (<b>5</b>), N­(SiMe₃)₂ (<b>6</b>), O<i>t</i>Bu (<b>7</b>)). Silylenes <b>1</b>–<b>7</b> have been prepared in quantitative yield by a modified ligand exchange reaction of PhC­(N<i>t</i>Bu)₂SiCl (LSiCl) with the corresponding lithium or potassium salts. Compounds <b>1</b>–<b>7</b> were characterized by spectroscopic and spectrometric techniques. Single-crystal X-ray structures of <b>1</b>, <b>3</b>, and <b>4</b> were determined

Stabilization of Low Valent Silicon Fluorides in the Coordination Sphere of Transition Metals

Silicon­(II) fluoride is unstable; therefore, isolation of the stable species is highly challenging and was not successful during the last 45 years. SiF₂ is generally generated in the gas phase at very high temperatures (∼1100–1200 °C) and low pressures and readily disproportionates or polymerizes. We accomplished the syntheses of stable silicon­(II) fluoride species by coordination of silicon­(II) to transition metal carbonyls. Silicon­(II) fluoride compounds L­(F)­Si·M­(CO)₅ {M = Cr (<b>4</b>), Mo (<b>5</b>), W­(<b>6</b>)} (L = PhC­(N<i>t</i>Bu)₂) were prepared by metathesis reaction from the corresponding chloride with Me₃SnF. However, the chloride derivatives L­(Cl)­Si·M­(CO)₅ {M = Cr (<b>1</b>), Mo (<b>2</b>), W­(<b>3</b>)} (L = PhC­(N<i>t</i>Bu)₂) were prepared by the treatment of transition metal carbonyls with L­(Cl)­Si. Direct fluorination of L­(Cl)Si with Me₃SnF resulted in oxidative addition products. Compounds <b>4</b>–<b>6</b> are stable at ambient temperature under an inert atmosphere of nitrogen. Compounds <b>4</b>–<b>6</b> were characterized by NMR spectroscopy, EI-MS spectrometry, and elemental analysis. The molecular structures of <b>4</b> and <b>6</b> were unambiguously established by single-crystal X-ray diffraction. Compounds <b>4</b> and <b>6</b> are the first structurally characterized fluorides, after the discovery of SiF₂ about four and a half decades ago