Atomically Precise Expansion of Unsaturated Silicon Clusters

Small- to medium-sized clusters occur in various areas of chemistry, for example, as active species of heterogeneous catalysis or as transient intermediates during chemical vapor deposition. The manipulation of stable representatives is mostly limited to the stabilizing ligand periphery, virtually excluding the systematic variation of the property-determining cluster scaffold. We now report the deliberate expansion of a stable unsaturated silicon cluster from six to seven and finally eight vertices. The consecutive application of lithium/naphthalene as the reducing agent and decamethylsilicocene as the electrophilic source of silicon results in the expansion of the core by precisely one atom with the potential of infinite repetition

‘Sons of athelings given to the earth’: Infant Mortality within Anglo-Saxon Mortuary Geography

FOR 20 OR MORE YEARS early Anglo-Saxon archaeologists have believed children are underrepresented in the cemetery evidence. They conclude that excavation misses small bones, that previous attitudes to reporting overlook the very young, or that infants and children were buried elsewhere. This is all well and good, but we must be careful of oversimplifying compound social and cultural responses to childhood and infant mortality. Previous approaches have offered methodological quandaries in the face of this under-representation. However, proportionally more infants were placed in large cemeteries and sometimes in specific zones. This trend is statistically significant and is therefore unlikely to result entirely from preservation or excavation problems. Early medieval cemeteries were part of regional mortuary geographies and provided places to stage events that promoted social cohesion across kinship systems extending over tribal territories. This paper argues that patterns in early Anglo-Saxon infant burial were the result of female mobility. Many women probably travelled locally to marry in a union which reinforced existing social networks. For an expectant mother, however, the safest place to give birth was with experience women in her maternal home. Infant identities were affected by personal and legal association with their mother’s parental kindred, so when an infant died in childbirth or months and years later, it was their mother’s identity which dictated burial location. As a result, cemeteries central to tribal identities became places to bury the sons and daughters of a regional tribal aristocracy

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Atomically Precise Expansion of Unsaturated Silicon Clusters

Small- to medium-sized clusters occur in various areas of chemistry, for example, as active species of heterogeneous catalysis or as transient intermediates during chemical vapor deposition. The manipulation of stable representatives is mostly limited to the stabilizing ligand periphery, virtually excluding the systematic variation of the property-determining cluster scaffold. We now report the deliberate expansion of a stable unsaturated silicon cluster from six to seven and finally eight vertices. The consecutive application of lithium/naphthalene as the reducing agent and decamethylsilicocene as the electrophilic source of silicon results in the expansion of the core by precisely one atom with the potential of infinite repetition

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Angewandte Chemie International Edition / Atomically precise expansion of unsaturated silicon clusters

Small to mediumsized clusters occur in various areas of chemistry, for example, as active species of heterogeneous catalysis or as transient intermediates during chemical vapor deposition. The manipulation of stable representatives is mostly limited to the stabilizing ligand periphery, virtually excluding the systematic variation of the propertydetermining cluster scaffold. We now report the deliberate expansion of a stable unsaturated silicon cluster from six to seven and finally eight vertices. The consecutive application of lithium/naphthalene as the reducing agent and decamethylsilicocene as the electrophilic source of silicon results in the expansion of the core by precisely one atom with the potential of infinite repetition.(VLID)460383

Reversible Base Coordination to a Disilene

Leszczynska K, Abersfelder K, Mix A, et al. Reversible Base Coordination to a Disilene. Angewandte Chemie International Edition. 2012;51(27):6785-6788

Potential Protecting Group Strategy for Disila Analogues of Vinyllithiums: Synthesis and Reactivity of a 2,4,6-Trimethoxyphenyl-Substituted Disilene

Proof of concept for the protection of the nucleophilic functionality of disilenidesdisila analogues of vinyllithiumwith preservation of the SiSi bond is reported. 1-Iodo-2,4,6-trimethoxybenzene (TMOP-I) reacts with lithium tris­(2,4,6-triisopropylphenyl)­disilenide (<b>1</b>), affording the disilene Tip₂SiSi­(Tip)­TMOP (<b>2</b>) in high yield. The presence of the TMOP group in disilene <b>2</b> enables the regioselective addition of polar substrates to the SiSi double bond, including water, ammonia, acetylenes, and isocyanides. NMR spectroscopic analysis of the reductive cleavage of the TMOP group and subsequent trapping of the corresponding disilenides with Me₃SiCl reveals KC₈ as a highly appropriate reducing agent for the selective deprotection

Potential Protecting Group Strategy for Disila Analogues of Vinyllithiums: Synthesis and Reactivity of a 2,4,6-Trimethoxyphenyl-Substituted Disilene

Proof of concept for the protection of the nucleophilic functionality of disilenidesdisila analogues of vinyllithiumwith preservation of the SiSi bond is reported. 1-Iodo-2,4,6-trimethoxybenzene (TMOP-I) reacts with lithium tris­(2,4,6-triisopropylphenyl)­disilenide (<b>1</b>), affording the disilene Tip₂SiSi­(Tip)­TMOP (<b>2</b>) in high yield. The presence of the TMOP group in disilene <b>2</b> enables the regioselective addition of polar substrates to the SiSi double bond, including water, ammonia, acetylenes, and isocyanides. NMR spectroscopic analysis of the reductive cleavage of the TMOP group and subsequent trapping of the corresponding disilenides with Me₃SiCl reveals KC₈ as a highly appropriate reducing agent for the selective deprotection