Both single tucked-in permethyltitanocene 1 and double tucked-in permethyltitanocene 2 react with excess CO₂ by insertion into their Ti–CH₂ bonds. The former one precipitates instantly a yellow carboxylate-tethered oligomer [3]_n which is insoluble in aprotic solvents and in a vacuum it sublimes as a monomer without decomposition. Computations for n ≤ 4 optimised the structure of the monomer [3] and showed that open chain oligomers bound by dative O → Ti bonds were not sterically hindered. The latter bond dissociates when [3]_n is oxidized by chlorination with CDCl₃ or CD₂Cl₂ to give Ti(IV) chloride 4 or upon metathesis of [3]_n with Me₃SiCl yielding Ti(III) chloride 5. Oxidative addition of MeCN affords a C–C coupled dinuclear titanocene diimine 6. Compound [3]_n also reacts with 1 to give the tethered carbodiolate 8 or with [Cp*₂TiH] (where Cp* = η⁵-C₅Me₅) to give the half-tethered carbodiolate 10. The non-tethered carbodiolate 12 was obtained from [Cp*₂TiH] and CO₂ yielding titanocene formate by reaction of the latter with another equivalent of [Cp*₂TiH]. All these carbodiolates contain Ti(III) metal atoms forming electronic triplet states of axial or orthorhombic symmetry. In contrast to the rapidly reacting 1 compound 2 reacts with excess CO₂ slowly in m-xylene at 100 °C using only one of its two Ti–CH₂ moieties. The structure of the obtained carbodiolate 13 indicates that the primary product analogous to 3 reacts with 2 more rapidly than with CO₂.

中文翻译：

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全甲基二茂钛衍生物与二氧化碳的反应

单嵌式全甲基二茂钛1和双嵌式全甲基二茂钛₂通过插入到它们的 Ti-CH ₂键中而与过量的 CO 2 反应。前者会立即沉淀出黄色的羧酸盐束缚低聚物 [ 3 ] _n，该低聚物不溶于非质子溶剂，在真空中作为单体升华而不分解。n ≤ 4 的计算优化了单体 [ 3 ] 的结构，并表明由配位 O → Ti 键结合的开链低聚物没有空间位阻。当 [ 3 ] _n被 CDCl _{3氯化氧化时，后一个键解离}或 CD ₂ Cl ₂得到 Ti( IV ) 氯化物4或 [ 3 ] _n与 Me ₃ SiCl 复分解得到 Ti( III ) 氯化物5。MeCN 的氧化加成得到 C-C 偶联双核二茂钛二亚胺6。化合物 [ 3 ] _n还与1反应得到束缚的碳二醇酯8或与 [Cp* ₂ TiH]（其中 Cp* = η ⁵ -C ₅ Me ₅）反应得到半束缚的碳二醇酯10. 非束缚碳二醇12由[Cp* ₂ TiH]和CO ₂获得，通过后者与另一当量的[Cp* ₂ TiH]反应产生二茂钛甲酸盐。所有这些碳二醇都含有 Ti( III ) 金属原子，形成轴向或正交对称的电子三重态。与快速反应1相比，化合物2仅使用其两个 Ti-CH ₂部分中的一个，在 100 °C 的间二甲苯中与过量 CO ₂缓慢反应。得到的碳二醇13的结构表明初级产物类似于3与2反应比与 CO ₂反应更快。