First Dinuclear B(II) Monocations with Bridging Guanidinate Ligands: Synthesis and Properties

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• 作者：Oxana Ciobanu ; Dimitri Emeljanenko ; Elisabeth Kaifer ; J&#xfc ; rgen Mautz ; Hans-Jö ; rg Himmel
• 刊名：Inorganic Chemistry
• 出版年：2008
• 出版时间：June 2, 2008
• 年：2008
• 卷：47
• 期：11
• 页码：4774 - 4778
• 全文大小：2565K
• 年卷期：v.47,no.11(June 2, 2008)
• ISSN：1520-510X

文摘

Reaction between the diborane (4) B₂Cl₂(NMe₂)₂ and Li(hpp) (hpp⁻ = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinate) leads to [(Me₂N)B(μ-hpp)]₂. This species can be protonated by HCl·OEt₂ to give [(Me₂HN)B(μ-hpp)]₂Cl₂featuring two B(II) cations with direct B−B bonding. The unsymmetrical monocation [(Me₂N)B₂(μ-hpp)₂(NHMe₂)]⁺ is also obtained. [(Me₂HN)B(μ-hpp)]₂Cl₂ eliminates NHMe₂ in a slow reaction leading to [ClB₂(μ-hpp)₂(NHMe₂)]Cl and ultimately, presumably, to [ClB(μ-hpp)]₂. We report the crystal structures of the two monocations [ClB₂(μ-hpp)₂(NHMe₂)]Cl and [(Me₂N)B₂(μ-hpp)₂(NHMe₂)]Cl. The experimental results are accompanied by some quantum chemical density-functional theory calculations.