A Spiro-Ge-Heterocyclic Compound Formation via Germylenoid and Formaldehyde: A Theoretical Study
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TRUCTURE OF MATTER AND QUANTUM CHEMISTRY
A Spiro-Ge-Heterocyclic Compound Formation via Germylenoid and Formaldehyde: A Theoretical Study Xiao-Lin Zhanga, Ming-Xia Zhanga, Bing-Fei Yana, and Wen-Zuo Lia* a
College of Chemistry and Chemical Engineering, Yantai University, Yantai, 264005 China * e-mail: [email protected] Received October 4, 2019; revised October 4, 2019; accepted October 15, 2019
Abstract—Addition reaction of the germylenoid H2GeLiF (R1) and formaldehyde HCHO (R2) leading to the formation of a spiro-Ge-heterocyclic compound was investigated theoretically by using the M062X and QCISD methods for the first time. The geometries of the stationary points along the potential energy surfaces of the addition reaction were optimized at the M062X/6-311+G(d,p) level at first, and then the single-point energies were calculated at QCISD/6-311++G(d,p) level. The addition reaction of H2GeLiF and HCHO firstly generated an oxagermacyclopropane (c-H2GeOCH2, P1) and then P1 can further react with HCHO along two possible pathways (paths II and III). At the end of path II, one spiro-Ge-heterocyclic product (P2) forms, which is the 2,4-dioxagermolane. At the end of path III, the other spiro-Ge-heterocyclic product (P3) forms, which is the 2,5-dioxagermolane. According to the calculated barrier heights we can conclude that the path II is more favorable than path III. Therefore the dominant reaction pathway of the addition reaction between H2GeLiF and HCHO is that firstly R1 + R2 → P1 and then P1 + R2 → P2. The computational studies suggest that this reaction model can provide new ideas for the synthesis of heterocyclic germanium compounds. Keywords: germylenoid H2GeLiF, formaldehyde, addition reaction, M062X, QCISD, spiro-Ge-heterocycles DOI: 10.1134/S0036024420100349
INTRODUCTION Germylenes are an interesting and exciting class of compounds, which belong to the family of heavier tetrylenes [1]. Since Lappert et al. [2] found these compounds can be handled under mild conditions, many germylenes have been synthesized and characterized, and the structures and reactivities of these germylenes have been also studied [3–8]. Germylenes can participate in many chemical reactions, such as insertion [9], addition [10], oxidation [11], reduction [12], and so on. Therefore, the germylenes can be used to synthesize new organogermanium and heterocyclic germanium compounds [13]. Germylenoid is one of important derivatives of germylene. In 1991 Gaspar et al. [14] postulated that germylenoid might be the intermediate in the reaction of lithium-induced dehalogenation of dichlorodimethylgermane. In 2000 Ichinohe et al. [15] proposed that in the reaction of GeCl2 · dioxane with t-Bu3SiNa, an active intermediate germylenoid t-Bu3SiGeCl2Na played an important role. In 2006 Tokitoh et al. [16, 17] pointed out one germylenoid Tbt(Dip)GeLiBr was a reactive intermediate in their synthesis of the stable crystalline bis(germacyclopropa)benzenes by the reaction of the corresponding dilithiogermane Tbt(Dip)GeLi2 with 1,2,4,5-tetrabromobenzene. In
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