Cerium-Hydride Secondary Building Units in a Porous Metal–Organic Framework for Catalytic Hydroboration and Hydrophosphination

Ji, Pengfei; Sawano, Takahiro; Lin, Zheng‐Zhe; Urban, Ania; Boures, Dean; Lin, Wenbin

doi:10.1021/jacs.6b10055

Cited by 77 publications

(65 citation statements)

References 58 publications

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“…12,[14][15] We note that a related approach to breaking strong M-O bonds of oxophilic centers is enabled by redox-active metal centers, for example with Ti complexes under homogeneous conditions, [16][17] or in metal-organic frameworks (MOFs), 18 as well as Ce-containing MOF catalyzed hydroboration of alkenes and pyridines. 19 The oxophilic lanthanide centers also form strong bonds to oxygen in metal oxides, which is a useful property for attaching these sites onto supports in heterogeneous catalysts. [20][21][22][23][24][25][26][27][28][29] Homoleptic compounds in particular, such as La(CH2Ph)3THF3 or La{CH(SiMe3)2}3, [30][31] have potential in surface organometallic chemistry (SOMC).…”

Section: Introductionmentioning

confidence: 99%

“…The 13 C CPMAS and 1 H{ 29 Si} idHETCOR spectra of 1@MSN550 and 1@MSN700 grafted in pentane are shown in Figure 2, along with the corresponding schematic structures and site assignments. The 1 H, 13 C and 19 Si chemical shifts, which are all attributable to silica-bound species, are listed in Table 2. The resonances labeled H1, H2, C1, C2 and Si1 can be assigned to 1@MSN (Figure 2A), based on the chemical shift values reported for 1 by solution-state NMR.…”

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confidence: 99%

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Silica-Supported Organolanthanum Catalysts for C–O Bond Cleavage in Epoxides

et al. 2020

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Single-site organolanthanum complexes supported on mesoporous silica nanoparticles, La{C(SiHMe2)3}n@MSNs, catalyze the ring-opening hydroboration reaction of aliphatic and styrenic epoxides with pinacolborane (HBpin). The surface-bound complexes, synthesized by reaction of the homoleptic tris(alkyl)lanthanum La{C(SiHMe2)3}3 and SBA-type MSN treated at 700 °C (MSN700), are mostly monopodal ≡SiO-La{C(SiHMe2)3}2 and contain an average of one bridging La↼H-Si per alkyl ligand. This structure was established through a combination of solid-state NMR (SSNMR) experiments, including J-resolved SiH coupling and quantitative 29Si measurements, diffuse reflectance IR, and elemental analysis. These rigorous analyses also established that grafting reactions in pentane provide a preponderance of ≡SiO-La{C(SiHMe2)3}2 sites and are superior to those in benzene and THF, and that grafting onto MSN treated at 550 °C (MSN550) results in a mixture of surface species. The single-site supported catalysts are more selective and in most cases more active than the homogeneous analogue, allow easy purification of products from the catalyst, are strongly resistant to leaching into solution phase, and may be recycled for reuse at least five times. After reaction of La{C(SiHMe2)3}n@MSN and HBpin, species including ≡SiO-La{C(SiHMe2)3}(H2Bpin) and ≡SiO-La{C(SiHMe2)3}{κ2-pinB-O(CMe2)2OBH3} are identified by detailed 1D and 2D 11B SSNMR experiments.ABSTRACT: Single-site organolanthanum complexes supported on mesoporous silica nanoparticles, La{C(SiHMe2)3}n@MSNs, catalyze the ring-opening hydroboration reaction of aliphatic and styrenic epoxides with pinacolborane (HBpin). The surface-bound complexes, synthesized by reaction of the homoleptic tris(alkyl)lanthanum La{C(SiHMe2)3}3 and SBA-type MSNs treated at 700 °C (MSN700), are mostly monopodal ≡SiO-La{C(SiHMe2)3}2 and contain an average of one bridging La↼H-Si per alkyl ligand. This structure was established through a combination of solid-state NMR (SSNMR) experiments, including J-resolved SiH coupling and quantitative 29 Si measurements, diffuse reflectance IR, and elemental analysis. These rigorous analyses also established that grafting reactions in pentane provide a preponderance of ≡SiO-La{C(SiHMe2)3}2 sites and are superior to those in benzene and THF, and that grafting onto MSN treated at 550 °C (MSN550) results in a mixture of surface species. The single-site supported catalysts are more selective and in most cases more active as the homogeneous analogue, allow easy purification of products from the catalyst, are strongly resistant to leaching into solution phase, and may be recycled for reuse at least five times. After reaction of La{C(SiHMe2)3}n@MSN and HBpin, species including ≡SiO-La{C(SiHMe2)3}(H2Bpin) and ≡SiO-La{C(SiHMe2)3}{κ 2 -pinB-O(CMe2)2OBH3} are identified by detailed 1D and 2D 11 B SSNMR experiments. AUTHOR INFORMATION Corresponding Authors

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Silica-Supported Organolanthanum Catalysts for C–O Bond Cleavage in Epoxides

et al. 2020

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“…Open metal ions or metal clusters in geometric frameworks of MOFs can be accessible to reactant substrates through the channels of the frameworks and serve as molecular active sites for catalytic reactions after the activation of MOFs by removing labile solvent molecules or counter ions. Some representative works are listed in Table 6 . For example, a Pd‐MOF with the molecular formula of [Pd(2‐pymo) 2 ] n (2‐pymo = 2‐hydroxypyrimidinolate) was fabricated to form the 3D sodalite‐type framework possessing two different hexagonal windows with free openings of 4.8 and 8.8 Å, characterized by X‐ray diffraction and DRUV–vis spectroscopy .…”

Section: Rational Design Of the Diverse Catalytic Sites In Crystallinmentioning

confidence: 99%

Rational Design of Catalytic Centers in Crystalline Frameworks

Yin

et al. 2018

Advanced Materials

114

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Crystalline frameworks including primarily metal organic frameworks (MOF) and covalent organic frameworks (COF) have received much attention in the field of heterogeneous catalysts recently. Beyond providing large surface area and spatial confinement, these crystalline frameworks can be designed to either directly act as or influence the catalytic sites at molecular level. This approach offers a unique advantage to gain deeper insights of structure-activity correlations in solid materials, leading to new guiding principles for rational design of advanced solid catalysts for potential important applications related to energy and fine chemical synthesis. In this review, recent key progress achieved in designing MOF- and COF-based molecular solid catalysts and the mechanistic understanding of the catalytic centers and associated reaction pathways are summarized. The state-of-the-art rational design of MOF- and COF-based solid catalysts in this review is grouped into seven different areas: (i) metalated linkers, (ii) metalated moieties anchored on linkers, (iii) organic moieties anchored on linkers, (iv) encapsulated single sites in pores, and (v) metal-mode-based active sites in MOFs. Along with this, some attention is paid to theoretical studies about the reaction mechanisms. Finally, technical challenges and possible solutions in applying these catalysts for practical applications are also presented.

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“…For example, unactivated alkene substrates remain underutilized, with limited success in a mere handful of examples. 9,10,11,12,13,14 Webster reported an intramolecular hydrophosphination with an iron(II) β-diketiminato complex (Chart 1, compound A) with these substrates. 9 A cerium hydride metal-organic framework (Chart 1, compound B) is capable of intermolecular hydrophosphination with diphenylphosphine and unactivated alkenes upon extended reaction times at relatively high temperature (80 °C and 5 days).…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic Hydrophosphination with Air-Stable and Commercially Available Bis(acetylacetonato)copper(II) (Cu(acac)2)

Dannenberg¹,

Waterman

2020

Preprint

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Bis(acetylacetonato)copper(II) (Cu(acac)2, 1), is active for the hydrophosphination of alkenes and alkynes with primary and secondary phosphines. Under thermal conditions, the activity of 1 is comparable to some of the best literature catalysts, but 1 is unique in that set possessing air- and water-stability. However, under ambient temperature irradiation centered at 360 nm, the conversions are remarkable with some reactions complete in minutes and several rarely reported unactivated substrates achieving high conversions within hours. The photocatalytic conditions are critical, and comparison to literature catalysts has been made in which 1 demonstrates superior activity. Initial mechanistic work does not suggest a radical mechanism rather the formation of a copper(I) active species. Hammett analysis indicates that depending on the substrate, either a nucleophilic or insertion-based mechanism may be at work. The enhanced reactivity provided by light also appears to be generalizable to other copper(I) compounds under irradiation, representing a broader phenomenon in metal catalyzed P–C bond formation. This simple, bench-stable, and inexpensive catalyst is highly effective, placing hydrophosphination in the hands of many more synthetic chemists.

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Cerium-Hydride Secondary Building Units in a Porous Metal–Organic Framework for Catalytic Hydroboration and Hydrophosphination

Cited by 77 publications

References 58 publications

Silica-Supported Organolanthanum Catalysts for C–O Bond Cleavage in Epoxides

Silica-Supported Organolanthanum Catalysts for C–O Bond Cleavage in Epoxides

Rational Design of Catalytic Centers in Crystalline Frameworks

Photocatalytic Hydrophosphination with Air-Stable and Commercially Available Bis(acetylacetonato)copper(II) (Cu(acac)2)

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