The boron carbonyl cluster cations in the form of B₃(CO)_n⁺ (n = 4–6) are produced and studied by infrared photodissociation spectroscopy in the carbonyl stretching frequency region in the gas phase. Their geometric structures are determined with the aid of density functional theory calculations. The B₃(CO)₄⁺ cation is characterized to have a D_2d (OC)₂B═B═B(CO)₂ structure and ¹A₁ electronic ground state with a linear boron skeleton. The B₃(CO)₅⁺ cation is determined to have a chain boron framework with C_2v symmetry. The B₃(CO)₆⁺ cation is a weakly bound CO-tagged complex involving a B₃(CO)₅⁺ ion core. Bonding analysis reveals that B₃(CO)₄⁺ has a chemical bonding pattern similar to allene, while bonding in B₃(CO)₅⁺ is similar to that in allyl anion.

中文翻译：

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烃的硼羰基类似物：B ₃（CO）_n ⁺（n = 4–6）的红外光解光谱研究

产生了B ₃（CO）_n ⁺（n = 4–6）形式的羰基硼簇阳离子，并通过红外光解光谱法在气相的羰基拉伸频率范围内对其进行了研究。它们的几何结构借助于密度泛函理论计算确定。在B ₃（CO）₄ ⁺阳离子的特征是具有d _{2 d}（OC）₂ B═B═B（CO）₂结构和^1个阿₁电子基态与线性硼骨架。B ₃（CO）₅ ⁺确定阳离子具有C _{2 v}对称性的链硼骨架。B ₃（CO）₆ ⁺阳离子是涉及B ₃（CO）₅ ⁺离子核的弱结合CO标签复合物。键合分析表明，B ₃（CO）₄ ⁺具有与烯丙基相似的化学键合模式，而B ₃（CO）₅ ^+中的键合与烯丙基阴离子相似。