Reactions of Group 4 Amide Guanidinates with Dioxygen or Water. Studies of the Formation of Oxo Products

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• 作者：Bhavna Sharma ; Tabitha M. Callaway ; Adam C. Lamb ; Carlos A. Steren ; Shu-Jian Chen ; Zi-Ling Xue
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：October 7, 2013
• 年：2013
• 卷：52
• 期：19
• 页码：11409-11421
• 全文大小：603K
• 年卷期：v.52,no.19(October 7, 2013)
• ISSN：1520-510X

文摘

Reactions of the zirconium amide guanidinates (R₂N)₂M[ⁱPrNC(NR₂)NⁱPr]₂ (R = Me, M = Zr, 1; M = Hf, 2; R = Et, M = Zr, 3) with O₂ or H₂O give products that are consistent with the oxo dimers {M(渭-O)[ⁱPrNC(NR₂)NⁱPr]₂}₂ (R = Me, M = Zr, 4; M = Hf, 5; R = Et, M = Zr, 6) and polymers {M(渭-O)[ⁱPrNC(NR₂)NⁱPr]₂}_n (R = Me, M = Zr, 7; M = Hf, 8; R = Et, M = Zr, 9). Mass spectrometric (MS) analyses of the reactions of water in air with 1 and 2 show formation of the Zr monomer Zr(鈺怬)[ⁱPrNC(NMe₂)NⁱPr]₂ (10), oxo dimers 4 and 5, and dihydroxyl complexes M(OH)₂[ⁱPrNC(NMe₂)NⁱPr]₂ (M = Zr, 11; Hf, 12). Similar MS analyses of the reaction of diethylamide guanidinate 3 with water in air show the formation of Zr(鈺怬)[ⁱPrNC(NEt₂)NⁱPr]₂ (13), Zr(OH)₂[ⁱPrNC(NEt₂)NⁱPr]₂ (14), 6, and {(Et₂N)Zr[ⁱPrNC(NEt₂)NⁱPr]₂}⁺ (15). Kinetic studies of the reaction between 1 and a continuous flow of 1.0 atm of O₂ at 80鈥?05 掳C indicate that it follows pseudo-first-order kinetics with 螖H = 8.7(1.1) kcal/mol, 螖S = 鈭?4(3) eu, 螖G_358聽K = 28(2) kcal/mol, and a half-life of 213(1) min at 85 掳C.