Facile immobilization of PNNNP-Pd pincer complexes in MFU-4l-OH and the effects of guest loading on Lewis acid catalytic activity
Facile immobilization of PNNNP-Pd pincer complexes in MFU-4l-OH and the effects of guest loading on Lewis acid catalytic activity
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PNNNP-Pd 钳形配合物在 MFU-4l-OH 中的轻松固定以及客体负载对路易斯酸催化活性的影响
DOI：
10.1039/d2dt03781e
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发表时间：
2023
影响因子：
4
通讯作者：
Wade, Casey R.
中科院分区：
文献类型：
--
作者：
Hilliard, Jordon S.;Wade, Casey R.
将钯二膦螯合物H3（PNNNP-PdI）包封在苯并三唑盐金属-有机骨架MFU-4l-OH ([Zn5(OH)4（btdd)3], btdd2−=双（1,2,3-三唑）二苯并二苯二酚）中，并研究了其作为香丹醛环化制异二酚的Lewis酸催化剂。框架节点上H3（PNNNP-PdI）苯甲酸取代基与Zn-OH基团之间的Brønsted酸碱反应促进了催化剂的快速固定化。催化剂的负载可以控制在每个配方单元最多0.5个钳形配合物[PdI-x， Zn5(OH)4−nx(btdd)3(H3−nPNNNP-PdI)xx = 0.06-0.5, n≈2.75]。通过氧化配体交换，在Pd-I位点用弱配位的BF4-阴离子取代I -，生成活化的PdBF4-x催化剂（x = 0.06, 0.10, 0.18, 0.40）。PdBF4-x系列的刘易斯酸催化活性随着催化剂密度的增加而降低，这是由于质量输运限制的出现。初始催化速率表明，PdBF4-0.06催化剂的活性接近均相PNNNP-PdBF4类似物的固有活性。此外，PdBF4-0.06表现出比基于金属油墨的MOF Zr-PdBF4更好的催化活性，并且在均相类似物中不受浸出或催化剂降解过程的影响。
A palladium diphosphine pincer complex H3(PNNNP-PdI) has been encapsulated in the benzotriazolate metal-organic framework MFU-4l-OH ([Zn5(OH)4(btdd)3], btdd2− = bis(1,2,3-triazolo)dibenzodioxin), and the resulting materials were investigated as Lewis acid catalysts for cyclization of citronellal to isopulegol. Rapid catalyst immobilization is facilitated by a Brønsted acid–base reaction between the H3(PNNNP-PdI) benzoic acid substituents and Zn–OH groups at the framework nodes. Catalyst loading can be controlled up to a maximum of 0.5 pincer complexes per formula unit [PdI-x, Zn5(OH)4−nx(btdd)3(H3−nPNNNP-PdI)xx = 0.06–0.5, n ≈ 2.75]. Oxidative ligand exchange was used to replace I− with weakly coordinating BF4− anions at the Pd–I sites, generating the activated PdBF4-x catalysts (x = 0.06, 0.10, 0.18, 0.40). The Lewis acid catalytic activity of the PdBF4-x series decreases with increasing catalyst density as a result of the appearance of mass transport limitations. Initial catalytic rates show that the activity of PdBF4-0.06 approaches the intrinsic activity of a homogeneous PNNNP-PdBF4 catalyst analogue. In addition, PdBF4-0.06 exhibits better catalytic activity than the metallolinker-based MOF Zr-PdBF4 and was not subject to leaching or catalyst degradation processes observed for the homogeneous analogue.