A Base-Resistant Metalloporphyrin Metal–Organic Framework for C–H Bond Halogenation

Abstract

A base-resistant porphyrin metal-organic framework (MOF), namely PCN-602 has been constructed with 12-connected [Ni(OH)(HO)Pz] (Pz = pyrazolate) cluster and a newly designed pyrazolate-based porphyrin ligand, 5,10,15,20-tetrakis(4-(pyrazolate-4-yl)phenyl)porphyrin under the guidance of the reticular synthesis strategy. Besides its robustness in hydroxide solution, PCN-602 also shows excellent stability in aqueous solutions of F, CO, and PO ions. Interestingly, the Mn-porphyrinic PCN-602, as a recyclable MOF catalyst, presents high catalytic activity for the C-H bond halogenation reaction in a basic system, significantly outperforming its homogeneous counterpart. For the first time, a porphyrinic MOF was thus used as an efficient catalyst in a basic solution with coordinating anions, to the best of our knowledge.

Stable ZnI‐Containing MOFs with Large [Zn70] Nanocages from Assembly of ZnII Ions and Aromatic [ZnI8] Clusters

“…[1][2][3] To date, various polynuclear metal cages in MOFs, as secondary buildingu nits (SBUs), were well documented and impressed, fore xample:[ Zn 24 ]a nd [Zn 48 ] cages in ZIF-8, [4] [Zn 32 ]c ages constructed by eight [Zn 4 O] clusters in MOF-5 and IRMOF series, [5] large [Zn 72 ]c ages from the assembly of eighteen [Zn 4 O] clusters in MOF-210, [6] [Cr 60 ]/[Cr 74 ] mesoporousc ages with 20/28 [Cr 3 O] clusters encapsulatedi n MIL-101(Cr), [7] as wella sm ore recent work [Ni 64 ]c ages in PCN-602, [8] [Zr 34 ]c ages in NPF-200, [9] and [Zr 36 ]c ages in PCN-700. [10] In these explorations, it shouldb en oted that the polynuclear metal cages in MOFs usually possess the following features: 1) metal ions of these cages mostly exhibit common oxidation states such as + 2, + 3, + 4r ather than rare low-oxidation-state (LOS) like Zn I ,M n I ,F e I ,C o I ,e tc.,s ince LOS metal ions are unstable in air andv ariouss olvents and tend to undergo disproportionation reaction; [4][5][6][7][8][9][10][11] 2) metal ions are frequently linked together through various small molecules/ions as bridges like OH À /O 2À ,N O 3 À ,C O 3 2À ,c arboxyl, and halogen, while metalmetal bonds hardly appeared in the polynuclear metal cages. [7,[10][11][12] In principle, the functions of MOF materials, like electronic,l uminescent, magnetic, catalytic properties, and so on, are intrinsically associated with the electronic configurations of metal ions in frameworks, which dependo nt he oxidation states of metal centers.…”

Selective C−H Halogenation with a Highly Fluorinated Manganese Porphyrin

“…[9] We have previously reported that electron-rich manganese porphyrins catalyze the efficient chlorination of aliphatic and benzylic C À Hb onds. [16] Missing from this repertoire is ag eneral method to halogenate substrates bearing electron-withdrawing groups and containing strained sp 3 CÀHs ites.H erein, we report the development of an electron-deficient manganese porphyrin, Mn(TPFPP)Cl (Figure 1), as an efficient catalyst for the selective C À Hh alogenation of av ariety of difficult and recalcitrant substrates.Moreover,this catalyst shows enzymelike selectivity. [14] Recently,B urns and co-workers applied this protocol to chlorinate as ensitive hydrocarbon ladderane,e nabling the total synthesis of an unusual membrane phospholipid.…”

Bimetallic Metal Organic Frameworks as Magnetically Separable Heterogeneous Catalysts and Photocatalytic Dye Degradation

“…Likewise, bimetallic Zn−Cu BTC MOF revealed higher desulfurization capacity than the monometallic Cu‐BTC and even zeolites . Similar studies showed that bimetallic MOF have superior catalytic activities over monometallic MOF being used as heterogeneous catalyst for organic coupling reactions, such as heck reaction, C−H bond halogenation, catalyzing OER reactions, selective oxidation of aromatic substrates, Knoevenagel condensation and Suzuki coupling reaction.,, Besides, some studies have dealt with photocatalytic properties of hybrid MOFs such as Fe/M(M=Mn, Co, Ni) MOFs, Fe(II)@MIL‐100(Fe) and MIL‐53(Fe) MOFs.,, Thus, the rational design and synthesis of hybrid structure with multi‐functionalities could achieve enhanced physicochemical properties and efficiency.…”

“…[9] Likewise, bimetallic ZnÀ Cu BTC MOF revealed higher desulfurization capacity than the monometallic Cu-BTC and even zeolites. [10] Similar studies showed that bimetallic MOF have superior catalytic activities over monometallic MOF being used as heterogeneous catalyst for organic coupling reactions [11,12] such as heck reaction, [13] CÀ H bond halogenation, [14] catalyzing OER reactions, [15] selective oxidation of aromatic substrates, [16] Knoevenagel condensation [17] and Suzuki coupling reaction., [18,19] Besides, some studies have dealt with photocatalytic properties of hybrid MOFs such as Fe/M (M=Mn, Co, Ni) MOFs, Fe(II)@MIL-100(Fe) and MIL-53(Fe) MOFs., [20,21] Thus, the rational design and synthesis of hybrid structure with multi-functionalities could achieve enhanced physicochemical properties and efficiency.Inspired with the possibility to improve the properties through introducing a new metal component in MOF, we hereby report the synthesis and crystal structure of a new bimetallic MOF composed of divalent Zn and trivalent Fe ions linked with 1,4-benzenedicarboxylic (BDC) acid to form FeÀ Zn BDC MOF.The pristine MOF doped or incorporated with another metal provide a scope to tune the electronic band gap. Recent studies show that the incorporation of iron as second metal in MOF decreases the band gap of parent MOF and enhanced its absorption into visible region.…”