A Novel Synthesis of Isoflavones via Copper(I)‐Catalyzed Intramolecular Cyclization Reaction

Isoflavone derivatives were synthesized via intramolecular cyclization of 3‐(2‐bromophenyl)‐3‐oxopropanal derivatives, using CuI as the catalyst, 2‐picolinic acid (=pyridine‐2‐carboxylic acid) as the ligand, K₂CO₃ as the base, and DMF as the solvent, in up to 96% yield. The synthesis is functional group‐tolerant.     

Photoresponsive Propeller-like Chiral AIE Copper(I) Clusters

A pair of propeller-like chiral trinuclear Cu^I clusters ( R/S-Cu3 ) with unique photoinduced fluorescence enhancement were prepared. R/S-Cu3 showed intense variable luminescence after UV light irradiation, which was attributed to the stepwise oxidation of ligand in the clusters. It exhibited typical aggregation-induced emission (AIE) (α_AIE=17.3). Mechanism studies showed that metal cluster-centered (MCC) and triplet metal-to-ligand charge-transfer (³MLCT) processes are the origin of the luminescence; the processes are regulated by a restriction of intramolecular motions mechanism in a different state. The chiral structure and AIE feature endow R/S-Cu3 with remarkable circularly polarized luminescence (g_lum=2×10⁻²) in the aggregated state. It shows good capability for producing reactive oxygen species. This work enriches the kinds of atomically precise AIE clusters, gains insight into their luminescence mechanism, and offers the prospect of application in multifunctional materials.     

Assembly of Chiral Two- and Three-dimensional Copper(I) Pseudohalide Based Coordination Polymers with Asymmetrically Substituted Pyrazine and Pyrimidine Ligands

The coordination polymers [(CuCN)₂(μ-2 Mepyz)], [CuCN(μ-2 Mepyz)] and [CuCN(μ-4 Mepym)] ( 1 – 3 ) (2 Mepyz = 2-methylpyrazine; 4 Mepym = 4-methylpyrimidine) may be prepared by self-assembly in acetonitrile solution at 100 °C ( 1 , 3 ) or without solvent at 20 °C ( 2 ). All three contain [CuCN] chains that are bridged by the bidentate aromatic ligands into sheets in 1 and 3 D frameworks in 2 and 3 . Reaction of CuSCN with these heterocyclic diazines at 100 °C leads to formation of the lamellar coordination polymers [(CuSCN)(μ-2 Mepyz)] ( 4 ) and [CuSCN · (4 Mepym-κN1)] ( 5 ), which contain respectively [CuSCN] chains and trans-trans fused [CuSCN] sheets as substructures. The presence of an asymmetric substitution pattern in 2 Mepyz and 4 Mepym induces the adoption of a chiral structure by 2 and 5 (space groups P2₁2₁2₁ and P1).     

Novel Copper (I) Trialkyl Trithiophosphite Complexes

Abstract

The series of copper (I) complexes with thiophosphite ligands was prepared and examined to determine the factors that affect the coordination mode of the ligand with metal.     

Synthesis and Coordination of Tripodal-Containing Copper(I) Complexes

Reaction of copper(I) chloride with 2,2-bis(diphenylphosphinomethyl)-l-phenylthiopropane P₂S produced a dimeric species [(P₂S)CuC1]₂ (2). Treatment of 2 with silver nitrate in acetonitrile gave a hexameric crystalline metal complex {[(P₂S)Cu(CH₃CN)]₆⁺6NO₃} (4), which had a “cyclodextrin-type” structure. A linear polymeric copper complex [(P₂S)Cu(NO₃)]_n was obtained by recrystallization of 4 in chloroform. These complexes were characterized by single crystal analyses, and their coordination behaviors in solution are discussed.     

A Novel Phase‐Transfer Catalyst: Monomeric Copper(II) Coordination Compound

The Copper(II) complex benzylcinchonidinium trichlorocuprate(II) ( 1 ) was obtained by the thermal treatments of CuCl₂ with benzylcinchonidinium chloride ( L1 ) in Pyrex tubes. The enantioselective efficiency of 1 studied by alkylation reaction of N‐(diphenylmethylene)glycine tert‐butyl ester ( L2 ) is similar to that of normal benzylcinchonidinium chloride ( L1 ).     

Temperature-controlled Hydrothermal Synthesis of Copper(I or II) Coordination Polymers via a Variety of Copper Coordination Modes

Two 1D coordination polymers Cu₂^I(C₆N₃H₄)₂(1) and Cu^II(C₆N₃H₄)₂·H₂O(2) based on benzotriazole(Bta) were hydrothermally synthesized by controlling the crystallization temperature. Single-crystal X-ray diffraction (XRD) analyses reveal that compound 1 is a 1D tubular structure constructed from two types of 1D chains {-Cu-N=N-N-}_n, where the Cu(I) ions adopt linear, triangular, and tetrahedral coordination modes to connect two types of Bta ligands via π-π interaction inside the tubular-like chain. For compound 2, the Cu(II) ions assume a quadrilateral coordination mode linking to the Bta ligands to give 1D straight chains, which stacks through π-π interactions to construct a 2D layer structure. Further characterizations including elemental analyses, infrared IR spectra, thermogravimetric(TG) analyses and luminescence properties have been done.     

Photoresponsive Propeller‐like Chiral AIE Copper(I) Clusters

A pair of propeller‐like chiral trinuclear Cu^I clusters ( R/S‐Cu3 ) with unique photoinduced fluorescence enhancement were prepared. R/S‐Cu3 showed intense variable luminescence after UV light irradiation, which was attributed to the stepwise oxidation of ligand in the clusters. It exhibited typical aggregation‐induced emission (AIE) (α_AIE=17.3). Mechanism studies showed that metal cluster‐centered (MCC) and triplet metal‐to‐ligand charge‐transfer (³MLCT) processes are the origin of the luminescence; the processes are regulated by a restriction of intramolecular motions mechanism in a different state. The chiral structure and AIE feature endow R/S‐Cu3 with remarkable circularly polarized luminescence (g_lum=2×10^?2) in the aggregated state. It shows good capability for producing reactive oxygen species. This work enriches the kinds of atomically precise AIE clusters, gains insight into their luminescence mechanism, and offers the prospect of application in multifunctional materials.     

A Novel Coordination Polymer Based on Decavanadate Units Linked by Copper(II) Ethylenediamine Complexes

Summary: A novel coordination polymer[{Cu(en)₂}(V₁₀O₂₈)]_n · 2n[Cu(en)₂(H₂O)] · 2n(H₃BO₃) · 2n(H₂O) was obtained by hydrothermal reaction. The compound crystallizes in the monoclinic crystal system, in the C2/c space group, with a = 26.490 (3) Å; b = 11.6558 (11) Å; c = 19.8426 (19) Å; β = 124.011 (1)°; V = 5078.6(8) ų. The solid structure is formed by polymeric chains, [Cu(en)₂(H₂O)]²⁺ cations, and boric acid and water solvate molecules, stabilized through a multiple hydrogen bond network.     

Copper(I) Coordination Polymers with Alkanedithiol and ‐dinitrile Bridging Ligands

CuI‐based coordination polymers with 1, 2‐ethanedithiol, 3, 6‐dioxa‐1, 8‐octanedithiol and 3‐oxa‐1, 5‐pentanedinitrile as respectively μ‐S, S′ and μ‐N, N′ bridging ligands have been prepared by reaction of CuI with the appropriate alkane derivative in acetonitrile. equation/tex2gif-stack-1.gif[Cu(HSCH₂CH₂SH)₂]I ( 1 ) contains 4⁴ cationic nets, equation/tex2gif-stack-2.gif[(CuI)₂(HSCH₂CH₂OCH₂CH₂OCH₂CH₂SH)] ( 2 ) neutral layers in which stairlike CuI double chains are linked by dithiol spacers. In contrast to these 2D polymers, equation/tex2gif-stack-3.gif[CuI(NCCH₂CH₂OCH₂CH₂CN)] ( 3 ) and equation/tex2gif-stack-4.gif[(CuI)₄(NCCH₂CH₂OCH₂CH₂CN)₂] ( 4 ) both contain infinite chains with respectively (CuI)₂ rings and distorted (CuI)₄ cubes as building units. Solvothermal reaction of CuI with the thiacrown ether 1, 4, 10‐trithia‐15‐crown‐5 (1, 4, 10TT15C5) in acetonitrile affords the lamellar coordination polymer equation/tex2gif-stack-5.gif[(CuI)₃(1, 4, 10TT15C5)] ( 7 ) in which copper atoms of individual CuI double chains are bridged in a μ‐S1, S4 manner. The third sulphur atom S10 of the thiacrown ether coordinates a copper(I) atom from a parallel chain to generate a 2D network.     

Enantioselective Copper(I)/Chiral Phosphoric Acid Catalyzed Intramolecular Amination of Allylic and Benzylic C−H Bonds

Radical‐involved enantioselective oxidative C?H bond functionalization by a hydrogen‐atom transfer (HAT) process has emerged as a promising method for accessing functionally diverse enantioenriched products, while asymmetric C(sp³)?H bond amination remains a formidable challenge. To address this problem, described herein is a dual Cu^I/chiral phosphoric acid (CPA) catalytic system for radical‐involved enantioselective intramolecular C(sp³)?H amination of not only allylic positions but also benzylic positions with broad substrate scope. The use of 4‐methoxy‐NHPI (NHPI=N‐hydroxyphthalimide) as a stable and chemoselective HAT mediator precursor is crucial for the fulfillment of this transformation. Preliminary mechanistic studies indicate that a crucial allylic or benzylic radical intermediate resulting from a HAT process is involved.     

Novel Copper(I) Complexes and Clusters with Phosphorus-Sulfur and Sulfur-Sulfur Containing Ligands

Abstract

The synthesis and coordination chemistry of ligands bearing PS donor groups in complexes with copper(I) halides, in particular thiophosphites, thiophosphonites, and thiophosphinites, are described.     

Cations Controlling the Chiral Assembly of Luminescent Atomically Precise Copper(I) Clusters

Chiral assembly and asymmetric synthesis are critically important for the generation of chiral metal clusters with chiroptical activities. Here, a racemic mixture of [K(CH₃OH)₂(18‐crown‐6)]⁺[Cu₅(S^tBu)₆]^? ( 1?CH₃OH ) in the chiral space group was prepared, in which the chiral red‐emissive anionic [Cu₅(S^tBu)₆]^? cluster was arranged along a twofold screw axis. Interestingly, the release of the coordinated CH₃OH of the cationic units turned the chiral 1?CH₃OH crystal into a mesomeric crystal [K(18‐crown‐6)]⁺[Cu₅(S^tBu)₆]^? ( 1 ), which has a centrosymmetric space group, by adding symmetry elements of glide and mirror planes through both disordered [Cu₅(S^tBu)₆]^? units. The switchable chiral/achiral rearrangement of [Cu₅(S^tBu)₆]^? clusters along with the capture/release of CH₃OH were concomitant with an intense increase/decrease in luminescence. We also used cationic chiral amino alcohols to induce the chiral assembly of a pair of enantiomers, [d /l ‐valinol(18‐crown‐6)]⁺[Cu₅(S^tBu)₆]^? ( d /l ‐Cu_5V ), which display impressive circularly polarized luminescence (CPL) in contrast to the CPL‐silent racemic mixture of 1?CH₃OH and mesomeric 1 .     

Intramolecular Copper(I)‐Catalyzed Interrupted Click–Acylation Domino Reaction

Acyl substituted triazoles are valuable scaffolds, but the direct synthesis of these moieties from terminal alkynes by copper catalysis remains unexplored. We report a robust, general, and efficient method using a simple CuI/2,2′‐bipyridine catalytic system. This transformation involves a copper catalyzed azide‐alkyne cycloaddition (CuAAC) followed by an intramolecular acylation onto a carbamoyl chloride. The reaction proceeds under mild conditions, tolerates several functional groups, and is readily scalable. This method represents a novel strategy towards the synthesis of complex heterocycles by a CuAAC/acylation domino process.     

Synthesis and Structural Characterization of two Novel Copper(I) Complexes with Oxygen Donor

Two novel copper(I) complexes with Cu‐O bonds, [Cu₂L₂(PPh₃)₂](BF₄)₂ ( 1 ) and [Cu(L)(dppeo)](BF₄) ( 2 ) ( L = 6‐(4‐diethylmethylphosphonatephenyl)‐2,2′‐bipyridine, dppeo = bis(diphenylphosphino)ethane monoxide), have been prepared and their structures characterized. In the binuclear complex 1 , the ligand L serves as tridentate donor with the N, N′ and O as coordination atoms, and the two Cu^I atoms are bridged through both P = O donor atoms in different ligand L with a triphenylphosphine molecule as auxiliary ligand. While in mononuclear complex 2 , both ligands L and dppeo behave as bidentate with N^∧N from L and P^∧O from dppeo chelating to Cu^I atom.     

A Luminescent One-Dimensional Copper(I) Polymer

The synthesis and structure of a one-dimensional polymer of formula [Cu₃(dpphp)₂(MeCN)_1.7(CH₂Cl₂)_0.3](ClO₄) _n is reported (where dpphp=6-diphenylphosphino-2-pyridonate). There are three distinct copper(I) sites within the polymer. Two of these sites are four-coordinate, bound to one P- and two O-atoms and a solvate molecule; the third site is bound only to two N-atoms. The Cu*Cu distances within the polymer are around 2.8 Å. The compound is luminescent in the solid-state.