A Stable Compound Containing a Silicon-Silicon Triple Bond

Abstract

The reaction of 2,2,3,3-tetrabromo-1,1,4,4-tetrakis[bis(trimethylsilyl)methyl]-1,4-diisopropyltetrasilane with four equivalents of potassium graphite (KC8) in tetrahydrofuran produces 1,1,4,4-tetrakis[bis(trimethylsilyl)methyl]-1,4-diisopropyl-2-tetrasilyne, a stable compound with a silicon-silicon triple bond, which can be isolated as emerald green crystals stable up to 100 degrees C in the absence of air. The SiSi triple-bond length (and its estimated standard deviation) is 2.0622(9) angstroms, which shows half the magnitude of the bond shortening of alkynes compared with that of alkenes. Unlike alkynes, the substituents at the SiSi group are not arranged in a linear fashion, but are trans-bent with a bond angle of 137.44(4) degrees.

The Nature of the Idealized Triple Bonds Between Principal Elements and the σ Origins of Trans-Bent Geometries—A Valence Bond Study

“…Inspection of the π-bond energy trends reveals that the in-plane bond is reduced to about 50% of its original strength in the linear structure when X and Y belong to group 14. Hence, in agreement with previous experimental and theoretical studies, 23,35,37 the formal number of bonds in these molecules is approximately 2 1 / 2 .…”

The Nature of the Idealized Triple Bonds Between Principal Elements and the σ Origins of Trans-Bent Geometries—A Valence Bond Study

“…Inspection of the π-bond energy trends reveals that the in-plane bond is reduced to about 50% of its original strength in the linear structure when X and Y belong to group 14. Hence, in agreement with previous experimental and theoretical studies, 23,35,37 the formal number of bonds in these molecules is approximately 2 1 / 2 .…”

Lewis Base and Metal Cation-Assisted Isomerization of Disilyne

“…The optimized structures of disilyne (PhSiSiPh) and disilavinylidene (Ph 2 SiSi) with Si–Si bond lengths 2.107 and 2.204 Å, respectively, were shown in Figure . For disilyne, the Si–Si bond length is consistent with the experimental and theoretical values (2.062 and 2.128 Å) reported by Sekiguchi et al and Huo et al The NBO analysis showed similar features found in heavier group 13 or 14 analogues of alkyne, , where the bonding between two central atoms is interpreted with a σ bond, a π bond, and a nonclassical “slipped” π bond (see Figure a1). For disilavinylidene, the bonding consists of one lone pair (Figure a2) and one normal double bond.…”

Silicon clusters with six and seven unsubstituted vertices via a two-step reaction from elemental silicon

“…A fragmentation mass experiment of 2a conrmed the composition by the loss of SnCy 3 in analogy to 1a and 3a. 30 1 H and 13 Fig. 2a) originate from the attached silyl groups and conform well to reported shis of the corresponding Ge 9 species {Si(TMS) 3 } 3 Ge 9…”

The Nature of the Idealized Triple Bonds Between Principal Elements and the σ Origins of Trans-Bent Geometries—A Valence Bond Study

“…Inspection of the π-bond energy trends reveals that the in-plane bond is reduced to about 50% of its original strength in the linear structure when X and Y belong to group 14. Hence, in agreement with previous experimental and theoretical studies, 23,35,37 the formal number of bonds in these molecules is approximately 2 1 / 2 .…”

Lewis Base and Metal Cation-Assisted Isomerization of Disilyne

“…The optimized structures of disilyne (PhSiSiPh) and disilavinylidene (Ph 2 SiSi) with Si–Si bond lengths 2.107 and 2.204 Å, respectively, were shown in Figure . For disilyne, the Si–Si bond length is consistent with the experimental and theoretical values (2.062 and 2.128 Å) reported by Sekiguchi et al and Huo et al The NBO analysis showed similar features found in heavier group 13 or 14 analogues of alkyne, , where the bonding between two central atoms is interpreted with a σ bond, a π bond, and a nonclassical “slipped” π bond (see Figure a1). For disilavinylidene, the bonding consists of one lone pair (Figure a2) and one normal double bond.…”

Silicon clusters with six and seven unsubstituted vertices via a two-step reaction from elemental silicon

“…A fragmentation mass experiment of 2a conrmed the composition by the loss of SnCy 3 in analogy to 1a and 3a. 30 1 H and 13 Fig. 2a) originate from the attached silyl groups and conform well to reported shis of the corresponding Ge 9 species {Si(TMS) 3 } 3 Ge 9…”

The Nature of the Idealized Triple Bonds Between Principal Elements and the σ Origins of Trans-Bent Geometries—A Valence Bond Study

“…Inspection of the π-bond energy trends reveals that the in-plane bond is reduced to about 50% of its original strength in the linear structure when X and Y belong to group 14. Hence, in agreement with previous experimental and theoretical studies, 23,35,37 the formal number of bonds in these molecules is approximately 2 1 / 2 .…”

Lewis Base and Metal Cation-Assisted Isomerization of Disilyne

“…The optimized structures of disilyne (PhSiSiPh) and disilavinylidene (Ph 2 SiSi) with Si–Si bond lengths 2.107 and 2.204 Å, respectively, were shown in Figure . For disilyne, the Si–Si bond length is consistent with the experimental and theoretical values (2.062 and 2.128 Å) reported by Sekiguchi et al and Huo et al The NBO analysis showed similar features found in heavier group 13 or 14 analogues of alkyne, , where the bonding between two central atoms is interpreted with a σ bond, a π bond, and a nonclassical “slipped” π bond (see Figure a1). For disilavinylidene, the bonding consists of one lone pair (Figure a2) and one normal double bond.…”

Silicon clusters with six and seven unsubstituted vertices via a two-step reaction from elemental silicon

“…A fragmentation mass experiment of 2a conrmed the composition by the loss of SnCy 3 in analogy to 1a and 3a. 30 1 H and 13 Fig. 2a) originate from the attached silyl groups and conform well to reported shis of the corresponding Ge 9 species {Si(TMS) 3 } 3 Ge 9…”