Ziwei Gao

Name: 高子伟; ZiWei Gao

Organization: Shaanxi Normal University

Department: School of Chemistry & Chemical Engineering

Title: Professor

Chemicals
References

Pd catalyzed couplings of “superactive esters” and terminal alkynes: Application to flavones and γ-benzopyranones construction

Co-reporter:Dandan Yang, Zhenhua Wang, Xiu Wang, Huaming Sun, Zunyuan Xie, Juan Fan, Guofang Zhang, Weiqiang Zhang, Ziwei Gao

Journal of Molecular Catalysis A: Chemical 2017 Volume 426(Part A) pp:24-29

Publication Date(Web):January 2017

DOI:10.1016/j.molcata.2016.10.030

•The flavones and γ-benzopyranones represent one of the most prevalent structural heterocycles in natural products.•In this manuscript, the diversity oriented synthesis of the flavones and γ-benzopyranones was accomplished by palladium catalyzed Sonogashira coupling reactions of o-acylated salicacly acid triazine esters and terminal alkynes, and sequentially, piperidine catalyzed 6-endo cyclization.•N-Methylmorpholine (NMM) significantly accelerated Pd catalyzed cross-coupling of the steric hindrined triazine esters and terminal alkynes with high efficiency and regioselectivity.•The new Pd/NMM catalyst system showed excellent functional groups tolerance for 24 examples of acylated o-alkynoylphenols derivatives.•The mechanistic experiments clearly demonstrated that NNM stabilized the catalytic palladium species, and promoted the leaving of triazine moiety during the catalytic cycle.•Under very mild condition, piperazine efficiently catalyzed 6-endo cyclization of the acylated o-alkynoylphenols derivatives, affording 24 examples of γ-benzopyranones with excellent yields.Lewis base, N-methylmorpholine (NMM) accelerated Pd-catalyzed Sonogashira coupling of steric hindered super active esters, 1a–1e, and terminal alkynes. This approach provided an efficient synthetic protocol for a broad array of acylated o-alkynoylphenols compounds, 3a–3e, under moderate conditions. The mechanistic study clearly demonstrated that NNM stabilized the catalytic palladium species, and accelerated the leaving of triazine moiety during the catalytic cycle of the cross-coupling reactions. In addition, piperazine was found to efficiently catalyze the 6-endo cyclization of acylated o-alkynoylphenols, which achieved the diversity oriented synthesis of γ-benzopyranones, 4aa–4eg, with 93–99% yields.

Photoluminescence and Hydrothermal Stability Correlations via Isoreticular/Structural fcu Rare-Earth Organic Frameworks Platform

Co-reporter:Yu-Feng Zhang, Dong-Xu XueZong-Hui Zhang, Qing Li, Ziwei Gao

Crystal Growth & Design 2017 Volume 17(Issue 3) pp:

Publication Date(Web):January 30, 2017

DOI:10.1021/acs.cgd.6b01880

Because of the discovery of a high-symmetry rare-earth hexanuclear secondary building unit, controllable design and assembly of rare-earth organic frameworks (REOFs) have become feasible. Subsequently, series of isoreticular/structural fcu REOFs platform was herein successfully produced by solvothermal reactions and reticular chemistry. After the crystal structural information and permanent porosity were confirmed, thorough investigations toward photoluminescence and hydrothermal stability were implemented. As a result, distinct and interesting luminescence behavior is observed among the series of REOFs. 1-Dy and 2-Dy mainly display ligand-centered emission, while 1-Eu and 2-Eu are predominated by metal-centered emission. More interestingly, 1-Eu reveals excitation dependent luminescence, generating the first example of a white light emission phosphor in single phase fabricated from a sole Eu3+ ion and sole organic linker. 2-Eu however does not exhibit such features and stays mostly unchanged upon the variation of excitation light. The above luminescence features were correlated by determination of the triplet state T1 energy of both L1 and L2 linkers via the phosphorescence at 77 K of 1-Gd and 2-Gd. Lastly, water resistance of the series of fcu REOFs was valued and it was found that 1-Dy constructed from a smaller ion radius and shorter organic linker exhibits the most prominent hydrothermal stability among the series of REOF platforms.

Preparation and characterization of layered carbon hybrid framework materials pillared with titanocene

Co-reporter:Huaming Sun;Dezhi Lin

Journal of Porous Materials 2017 Volume 24( Issue 2) pp:291-296

Publication Date(Web):2017 April

DOI:10.1007/s10934-016-0262-4

Novel graphene oxide layered hybrid framework materials pillared titanocene organometallic complex were prepared through a facile ultrasound intercalation approach. The products exhibited periodic layered structures with expanded interlayer spacing as characterized by XRD. Raman spectroscopy demonstrated that the skeleton structure of layered carbon still remained after titanocene treatment. Nitrogen sorption analysis indicated that the building blocks of graphene oxide sheets were cross-linked with titanocene molecules to form lamellar porous structures.

A dual-functional indium–organic framework towards organic pollutant decontamination via physically selective adsorption and chemical photodegradation

Co-reporter:Qing Li;Dong-Xu Xue;Yu-Feng Zhang;Zong-Hui Zhang;Junfeng Bai

Journal of Materials Chemistry A 2017 vol. 5(Issue 27) pp:14182-14189

Publication Date(Web):2017/07/11

DOI:10.1039/C7TA02216F

Through solvothermal reaction of In(NO3)3·5H2O and a highly conjugated carboxylate-based tritopic linker, a doubly interpenetrated indium–organic framework, 1, has been successfully prepared. As revealed by single-crystal X-ray diffraction, the isolated 1 displays an anionic framework and channel-type interior spaces replete with imidazole rings and free carboxylate oxygens. Due to its unique structural features, 1 demonstrates not only selective adsorption of cationic MB concomitant with anionic MO molecules with high selectivity, uptake, and adsorption rate, and good reversibility and recyclability, but also photocatalytic activity to efficiently decompose dyes MB and MO under the illumination of either UV or visible light due to the formation of MB@1 and MO/1 composites. The new finding of visible light responsive MB@1 and MO/1 composites may open up more applications.

Triple zirconocene/brønsted acid/CuO cooperative and relay catalysis system for tandem Mannich addition/C–C formative cyclization/oxidation

Co-reporter:Yanlong Luo;Huaming Sun;Weiqiang Zhang;Xiu Wang;Shan Xu;Guofang Zhang;Yajun Jian

RSC Advances (2011-Present) 2017 vol. 7(Issue 46) pp:28616-28625

Publication Date(Web):2017/05/30

DOI:10.1039/C7RA00870H

A new triple cooperative and relay catalysis system featuring the Mannich addition followed by C–C construction and oxydehydrogenation is described. The zirconocene dichloride and trimellitic acid synergic catalysis triggered the Mannich addition and C–C bond construction reactions, while CuO allowed relay catalysis for oxydehydrogenation. This novel strategy demonstrated superior activity for the synthesis of substituted quinolines from commercially available anilines, aldehydes and ketones. The corresponding substituted quinolines were synthesized with 32 examples in 90–96% yields under mild reaction conditions. A novel zirconocene–Brønsted acid complex, generated in situ and acting as an active catalyst, was validated from the mechanistic studies.

A copper-organic framework as scavenger towards organic dyes pollutants via physical adsorption and visible-light photodegradation

Co-reporter:Qing Li, Dong-Xu Xue, Yu-Feng Zhang, Zong-Hui Zhang, Qian Wang, Ziwei Gao, Junfeng Bai

Inorganic Chemistry Communications 2017 Volume 85(Volume 85) pp:

Publication Date(Web):1 November 2017

DOI:10.1016/j.inoche.2017.06.021

A 2-periodic copper–organic framework of 1 has been deliberately obtained via solvothermal reaction between Cu(NO3)2·3H2O and a V-shaped highly conjugated organic linker. Single-crystal X-ray structural analyses reveal that 1 displays a 3D stacking structure along with channel-typed interior architectures decorated with amino and trifluoromethoxy functionalized groups. 1 demonstrates not only notably selective encapsulation of small-sized MB and MO molecules with high adsorption rate, but also efficient photodegradation activities through decomposing MB, MO and large-sized phthalocyanine of reactive blue 21 under visible light irradiation.Solvothermal reaction between Cu(NO3)2·3H2O and a V-shaped highly conjugated organic linker, a 2-periodic copper–organic framework of 1 has been deliberately obtained. Due to its uniquely architectural features, 1 demonstrates not only notably selective encapsulation of small-sized MB and MO dye molecules with high adsorption rate, but also efficient photodegradation activities through decomposing dyes of MB, MO and bulky phthalocyanine of reactive blue 21 under visible light irradiation.Download high-res image (447KB)Download full-size image

Solvent strategy for unleashing the Lewis acidity of titanocene dichloride for rapid Mannich reactions

Co-reporter:Ya Wu, Xiu Wang, Yanlong Luo, Jing Wang, Yajun Jian, Huaming Sun, Guofang Zhang, Weiqiang Zhang and Ziwei Gao

RSC Advances 2016 vol. 6(Issue 19) pp:15298-15303

Publication Date(Web):21 Jan 2016

DOI:10.1039/C5RA27094D

The remarkable activation effect of alcohol solvent on kinetically inert titanocene dichloride was found to promote rapid three-component Mannich reactions. NMR and ESI-MS analyses as well as a control experiment of catalytic active species elucidated that the coordination of MeOH to the titanocene moiety unleashed the Lewis acid [Cp2Ti(OMe)2] and Brønsted acid HCl, which led to the enhanced catalytic activity of [Cp2TiCl2].

Ethanol promoted titanocene Lewis acid catalyzed synthesis of quinazoline derivatives

Co-reporter:Yanlong Luo, Ya Wu, Yunyun Wang, Huaming Sun, Zunyuan Xie, Weiqiang Zhang and Ziwei Gao

RSC Advances 2016 vol. 6(Issue 70) pp:66074-66077

Publication Date(Web):29 Jun 2016

DOI:10.1039/C6RA14583C

An efficient catalytic system involving in situ activation of kinetically inert titanocene dichloride with alcoholic solvent for the synthesis of quinazoline derivatives was developed. 1 mol% Cp2TiCl2 at 30 °C afforded 17 examples of quinazoline derivatives with yields of 95–98% in 7–12 minutes. Mechanistic experiments using in situ NMR and HRMS established that the coordination of ethanol to the titanocene moiety released the catalytic species [Cp2Ti(OCH2CH3)2].

Sigma-spacer regulated thiophenyl triazine conjugates: synthesis and crystal, electronic and luminescent properties

Co-reporter:Zhuangli Zhu, Ersha Shao, Shan Xu, Huaming Sun, Guofang Zhang, Zunyuan Xie, Weiqiang Zhang and Ziwei Gao

RSC Advances 2016 vol. 6(Issue 80) pp:76883-76889

Publication Date(Web):08 Aug 2016

DOI:10.1039/C6RA13795D

A water-accelerated Pd catalyzed Suzuki–Miyaura cross-coupling reaction was developed for the synthesis of thiophenyl triazine conjugates (TTCs). The compounds (2a–2e and 3a–3e) with five σ-spacers were obtained and fully characterized. The X-ray analysis of 2a, 2d, and 3d found that the length of the intermolecular H bond was 3.465(3) Å and the π–π interactions ranged from 3.6538(2)–3.9519(1) Å. Five σ-spacers of TTCs had an effect on their emissions from blue (363 nm) to yellow (530 nm) whilst 2- and 3-thiophenyl chromophores finely tune the emission from 530 to 504 nm. The DFT computation showed the TTCs had low HOMO (−6.8 eV) and LUMO (−2.5 eV) energy and high triplet energy (ET, 2.4 eV). The energy level and gap of TTCs were regularly modulated by the σ-spacer.

Synthesis of air-stable mixed bis-carboxylate titanocene complexes and their catalytic behaviors in cross-aldol and Mannich reactions

Co-reporter:Jing Wang;Xi Chen;Xiu Wang;Wei-Qiang Zhang;Hua-Ming Sun

Transition Metal Chemistry 2016 Volume 41( Issue 7) pp:731-738

Publication Date(Web):2016 October

DOI:10.1007/s11243-016-0054-3

Tunable organometallic Lewis acid catalysts were developed by combining salicylic acid (H2-Sal) with benzoic acid (H-Ben), 4-fluorobenzoic acid (H-BenF) and 3-thiophenic acid (H-Th), as coligands for mixed bis-carboxylate titanocene complexes. Three air-stable complexes [Cp2Ti(η1-HSal)(η1-Ben)] (1), [Cp2Ti(η1-HSal)(η1-BenF)] (2) and [Cp2Ti[η1-HSal][(η1-Th)] (3) were prepared in high yields by the reaction of salicylato titanocene chelate with carboxylate ligands. The mixed bis-carboxylate titanocene complexes were fully characterized by physicochemical and spectroscopic methods. Single-crystal X-ray diffraction studies revealed Ti–O(H-Sal) bond distances in 1, 2 and 3 of 1.972(3), 1.9245(18) and 1.912(5) Å, respectively, while the bond distances involving the coligands of 1, 2 and 3 are 1.908(3) Å (Ti–OBen), 1.9296(19) Å (Ti–OBenF) and 1.945(5) Å (Ti–OTh), respectively. These bis-carboxylate titanocene complexes showed satisfactory activities and selectivities in Mannich and cross-aldol reactions. Notably, complex 3 bearing the labile thiophene carboxylate ligand gave high yields with a diastereomer ratio (d.r.) as high as 1:99 for the direct Mannich reactions of benzaldehyde, cyclohexanone and aniline. In cross-aldol reaction of benzaldehyde and cyclohexanone, 1 and 2 successfully catalyzed the formation of double-aldol products in up to 99 % yield.

Privilege Ynone Synthesis via Palladium-Catalyzed Alkynylation of “Super-Active Esters”

Co-reporter:Bo Yu, Huaming Sun, Zunyuan Xie, Guofang Zhang, Li-Wen Xu, Weiqiang Zhang, and Ziwei Gao

Organic Letters 2015 Volume 17(Issue 13) pp:3298-3301

Publication Date(Web):June 12, 2015

DOI:10.1021/acs.orglett.5b01466

A neat palladium-catalyzed alkynylation reaction was developed with “super-active ester” as the carbonyl electrophile, which provides a clean and efficient synthetic protocol for a broad array of ynone compounds under CO-, Cu-, ligand-, and base-free conditions. The superior activity of triazine ester was rationalized by the strong electron-withdrawing ability and the unique affinity of triazine on palladium. A mechanistic experiment clearly demonstrated that the N–Pd coordination of triazine plays a crucial role for the highly efficient C–O activation.

Titanocene dichloride and poly(o-aminophenol) as a new heterogeneous cooperative catalysis system for three-component Mannich reaction

Co-reporter:Xuyang Zhu, Chun Chen, Binxun Yu, Ya Wu, Guofang Zhang, Weiqiang Zhang and Ziwei Gao

Catalysis Science & Technology 2015 vol. 5(Issue 9) pp:4346-4349

Publication Date(Web):14 Jul 2015

DOI:10.1039/C5CY00793C

A new heterogeneous cooperative catalysis system featuring the synergistic effect of an organometallic Lewis acid and a Brønsted acid supporter was developed. The catalysis system successfully catalyzed the direct Mannich reaction of both aromatic and aliphatic ketones in excellent yields. The catalyst can be recycled at least five times and the yield of the Mannich product remains over 90%.

Low-migratory ionic ferrocene-based burning rate catalysts with high combustion catalytic efficiency

Co-reporter:Xuelin Liu, Weiqiang Zhang, Guofang Zhang and Ziwei Gao

New Journal of Chemistry 2015 vol. 39(Issue 1) pp:155-162

Publication Date(Web):01 Oct 2014

DOI:10.1039/C4NJ01216J

Alkyl substituted ferrocenes can catalyze the burning of composited solid propellants efficiently. These non-polar and volatile ferrocenes, however, migrate to the surface of the propellants during prolonged storage, which would alter the designed burning parameters, and more seriously cause unexpected explosions. To tackle this problem, twelve ionic ferrocene derivatives bearing methylimidazolium and methyltriazolium substituents with nitrate and picrate anions as new ionic ferrocene-based burning rate catalysts were synthesized. The compounds were fully characterized by 1H NMR, 13C NMR and elemental analysis. Ten of them were characterized by single-crystal X-ray diffraction. Compounds 2 and 3 crystallize in the monoclinic space group P2(1)/n and P2(1)/c, respectively. Compounds 4·H2O, 6·1/2H2O, 8–10 and 12 crystallize in the triclinic space group P. Compounds 7 and 11 crystallize in the orthorhombic space group Pna21 and Pna2(1), respectively. Cyclic voltammetry investigations revealed that all the compounds exhibit quasi-reversible redox systems. Migration studies confirmed that the migration of these ionic ferrocenes is much slower than that of 2,2-bis(ethylferrocenyl)propane. The migration trend of the compounds is dependent on molecular structures of the ionic ferrocenes and that shorter alkyl chain lengths in the heterocyclic rings lead to slower migration rates. Their high thermal stability was determined by TG and DSC analyses (peak temperatures >172 °C). The thermal degradation of ammonium perchlorate (AP) catalyzed by the new burning-rate catalysts was evaluated by DSC methods. In the presence of nitrate (1–6) in 4 wt% or picrate (7–12) in 5 wt%, the peak decomposition temperature of AP shifts left significantly while the released heat increases dramatically. The catalytic activity of an ionic compound with a triazole ring in its cation is higher than its corresponding analog with an imidazole ring and the catalytic activity of a nitrate is generally higher than its picrate counterpart.

Unexpected and powerful effect of chlorobenzene in direct palladium-catalyzed cascade Sonogashira–hydroarylation reaction

Co-reporter:Bo Yu, Wei Xu, Huaming Sun, Binxun Yu, Guofang Zhang, Li-Wen Xu, Weiqiang Zhang and Ziwei Gao

RSC Advances 2015 vol. 5(Issue 11) pp:8351-8354

Publication Date(Web):15 Dec 2014

DOI:10.1039/C4RA13979H

A ubiquitous accelerating effect of chlorobenzene (PhCl) was observed unexpectedly in the Pd-catalyzed cascade Sonogashira–hydroarylation reaction. This new type of carbon–carbon bond forming cross-coupling reaction was efficiently catalysed by Pd2(dba)3 in the presence of a catalytic amount of PhCl, which provides a facile and direct approach to the synthesis of trisubstituted olefins.

Single-site SBA-15 supported zirconium catalysts. Synthesis, characterization and toward cyanosilylation reaction

Co-reporter:Wei Xu, Bo Yu, Ying Zhang, Xi Chen, Guofang Zhang, Ziwei Gao

Applied Surface Science 2015 Volume 325() pp:227-234

Publication Date(Web):15 January 2015

DOI:10.1016/j.apsusc.2014.11.064

Highlights

•: Some Zr active species have been anchored on the surface of SBA-15 by SOMC technique.
•: The structures of the Zr species have been characterized by a variety of techniques.
•: The anchored Zr species are single-sited surface complexes.
•: The Zr surface complexes are catalytic active for cyanosilylation of benzaldehyde.

Copper-catalyzed C(sp2)C(sp) Sonogashira-type cross-coupling reactions accelerated by polycyclic aromatic hydrocarbons

Co-reporter:Wei Xu;Bo Yu;Huaming Sun;Guofang Zhang;Weiqiang Zhang

Applied Organometallic Chemistry 2015 Volume 29( Issue 6) pp:353-356

Publication Date(Web):

DOI:10.1002/aoc.3298

Copper-catalyzed Sonogashira-type reactions were dramatically accelerated by introducing a catalytic amount of polycyclic aromatic hydrocarbon additive. This novel catalytic system features low copper loading (0.5 mol% < Cu < 5 mol%), broad reaction scope and remarkable substrate tolerance. Both aromatic and aliphatic terminal alkynes as well as diverse aryl iodides were employed in this transformation, affording respectable yields of the desired products. The novel Cu(OTf)₂/pyrene system was subsequently employed to synthesize phenylacetylene-based fluorescent compounds. Copyright © 2015 John Wiley & Sons, Ltd.

Organophosphate-accelerated copper-catalyzed C(sp2)C(sp) Sonogashira-type cross couplings

Co-reporter:Wei Xu;Bo Yu;Huaming Sun;Guofang Zhang;Weiqiang Zhang

Applied Organometallic Chemistry 2015 Volume 29( Issue 5) pp:301-304

Publication Date(Web):

DOI:10.1002/aoc.3291

A dramatic acceleration in copper-catalyzed Sonogashira-type reactions was observed when an organophosphate was used as additive. The catalyst systems featuring low copper loading (0.5 mol% < Cu < 5 mol%) gave Sonogashira-type products with a broad scope of aromatic and aliphatic terminal alkynes as well as aryl iodides in good to excellent yields. Among the organophosphate/copper catalytic systems, that of 4 mol% Cu(OTf)₂/10 mol% (R)-(−)-1,1′-binaphthyl-2,2′-diyl hydrogenphosphate exhibited the highest catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.

Conversion of 2-Furylcarbinols with Alkyl or Aryl Azides to Highly Functionalized 1,2,3-Triazoles via Cascade Formal [3 + 2] Cycloaddition/Ring-Opening

Co-reporter:Jiawei Guo, Binxun Yu, Ya-Nan Wang, Dongyu Duan, Li-Li Ren, Ziwei Gao, and Jing Gou

Organic Letters 2014 Volume 16(Issue 19) pp:5088-5091

Publication Date(Web):September 15, 2014

DOI:10.1021/ol502437y

A Lewis acid promoted cascade cycloaddition/ring-opening of 2-furylcarbinols with alkyl or aryl azides is described. The reaction features an initial formal [3 + 2] cycloaddition to form a trisubstitued triazole motif, followed by a ring opening of furan to generate the (E)-configuration of the enone. A wide range of highly functionalized triazoles is expediently and efficiently synthesized in a highly step-economical manner.

Sonogashira Couplings on the Surface of Montmorillonite-Supported Pd/Cu Nanoalloys

Co-reporter:Wei Xu, Huaming Sun, Bo Yu, Guofang Zhang, Weiqiang Zhang, and Ziwei Gao

ACS Applied Materials & Interfaces 2014 Volume 6(Issue 22) pp:20261

Publication Date(Web):October 15, 2014

DOI:10.1021/am505798y

To explore the true identity of palladium-catalyzed Sonogashira coupling reaction, montmorillonite (MMT)-supported transition metal nanoparticles (MMT@M, M = Pd, Cu, Fe, and Ni) were prepared, characterized, and evaluated systematically. Among all MMT@M catalysts, MMT@Pd/Cu showed the highest activity, and it was successfully extended to 20 examples with 57%–97% yields. The morphology characterization of MMT@Pd/Cu revealed that the crystalline bimetallic particles were dispersed on a MMT layer as nanoalloy with diameters ranged from 10 to 11 nm. In situ IR analysis using CO as molecular probe and XPS characterization found that the surface of Pd/Cu particles consisted of both catalytic active sites of Pd(0) and Cu(I). The experiments on the catalytic activities of MMT@M found that Pd/Cu catalyst system exhibited high activity only in nanoalloy form. Therefore, the Pd/Cu nanoalloy was identified as catalyst, on which the interatom Pd/Cu transmetalation between surfaces was proposed to be responsible for its synergistic activity.Keywords: bimetallic catalysis; CO absorption; montmorillonite; nanoalloy; Sonogashira coupling

Salicylato Titanocene Complexes as Cooperative Organometallic Lewis Acid and Brnsted Acid Catalysts for Three-Component Mannich Reactions

Co-reporter:Dr. Ya Wu;Chun Chen;Gai Jia;Xuyang Zhu;Dr. Huaming Sun; Guofang Zhang; Weiqiang Zhang; Ziwei Gao

Chemistry - A European Journal 2014 Volume 20( Issue 28) pp:8530-8535

Publication Date(Web):

DOI:10.1002/chem.201402438

Abstract

A binary acid system has been developed that features an air-stable organometallic precursor, titanocene dichloride, and simple organic cooperative Brønsted acids, which allowed for mild and highly efficient Mannich reactions of both aryl and alkyl ketones with excellent yields and satisfactory diastereoselectivity. Mechanistic studies, including ¹H NMR titration, X-ray structure analyses as well as isolation of catalytically active species, elucidated the dramatic synergistic effects of this new binary acid system.

5-Sulfosalicylic acid catalyzed direct Mannich reaction in pure water

Co-reporter:Chun Chen, Xuyang Zhu, Ya Wu, Huaming Sun, Guofang Zhang, Weiqiang Zhang, Ziwei Gao

Journal of Molecular Catalysis A: Chemical 2014 Volume 395() pp:124-127

Publication Date(Web):December 2014

DOI:10.1016/j.molcata.2014.08.017

•A green system for metal- and surfactant-free Mannich reactions was established.•5-Sulfosalicylic acid is superior recyclable water-soluble organocatalyst.•The catalytic Mannich reactions afforded β-amino ketones with excellent yields.•The catalyst can be recycled in water whereas the product isolated by filtration.•A new single crystal confirmed the anti-conguration of products.A water-soluble Brønsted acid, 5-sulfosalicylic acid, efficiently catalyzed the direct three-component Mannich reactions of cyclohexanone and 3-pentanone in pure water. 21 Examples of Mannich reactions were presented, which afforded the corresponding β-amino ketones with up to 97% yield and decent diastereoselectivities. The acid catalyst can be recycled as an aqueous solution for at least six times and the yield of the Mannich product remained over 90%.

An Efficient and Recyclable Catalyst for N-Alkylation of Amines and -Alkylation of Secondary Alcohols with Primary Alcohols: SBA-15 Supported N-Heterocyclic Carbene Iridium Complex

Co-reporter:Dong Wang;Xu-Qing Guo;Chen-Xi Wang;Ya-Nong Wang;Rui Zhong;Xiao-Han Zhu;Li-Hua Cai;Zi-Wei Gao;Xiu-Feng Hou

Advanced Synthesis & Catalysis 2013 Volume 355( Issue 6) pp:1117-1125

Publication Date(Web):

DOI:10.1002/adsc.201200732

Abstract

A mesoporous silica (SBA-15)-supported pyrimidine-substituted N-heterocyclic carbene iridium complex was prepared and used as a catalyst for both environmentally friendly N-alkylation of amines and β-alkylation of secondary alcohols with primary alcohols. The structure of the supported iridium catalyst was characterized by Fourier transform infrared (FT-IR), ¹³C and ²⁹Si solid-state nuclear magnetic resonance (NMR), small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), iridium K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopic analyses which demonstrated that the coordination environment of the iridium centre and the 3-dimensional-hexagonal pore structure of SBA-15 were retained after the immobilization. The catalyst was found to be highly efficient for both kinds of reaction on a wide range of substrates under mild conditions. Moreover, the supported iridium catalyst was obviously superior to the unsupported one in the N-alkylation of aniline and β-alkylation of 1-phenylethanol with benzyl alcohol as substrate, which indicated that not only the iridium complex moiety but also the support material contributed to the catalytic activity of the supported iridium catalyst in these reactions. The supported iridium catalyst can be easily recycled by simple washing without chemical treatment, and exhibited excellent recycling performance without notable decrease in catalytic efficiency even after twelve test cycles for N-alkylation of aniline with benzyl alcohol, nine cycles for N-alkylation of different amines with different alcohols, and eight cycles for β-alkylation of 1-phenylethanol with benzyl alcohol, respectively.

Oriented growth of urchin-like zinc oxide micro/nano-scale structures in aqueous solution

Co-reporter:Kun Hou, Ziwei Gao, Min Da, Zimei Li, Huaming Sun, Jinling Li, Yunhui Xie, Taoying Kang, Alimjan Mijit

Materials Research Bulletin 2012 47(4) pp: 1010-1015

Publication Date(Web):

DOI:10.1016/j.materresbull.2012.01.006

Ethanol catalyzed synthesis of titanocene aryl carboxylate complexes and crystal structure of (η5-C5H5)2Ti(2-OH-5-S–O2CC6H3)2

Co-reporter:Jin-Ling Li, Zi-Wei Gao, Ping Sun, Ling-Xiang Gao, Wayne Tikkanen

Inorganica Chimica Acta 2011 Volume 368(Issue 1) pp:231-236

Publication Date(Web):15 March 2011

DOI:10.1016/j.ica.2010.12.037

A method for the synthesis of titanocene (IV) aryl carboxylate complexes is presented in this paper. It is based on the fact that alcohol can catalyze the reaction between Cp2TiCl2 and aryl carboxylate ligands in the presence of sodium hydroxide (NaOH). The effects of the catalyst on the reaction system were studied and the possible reaction mechanism was proposed. This method was used to prepare a series of titanocene (IV) aryl carboxylate complexes and a macrocyclic titanocene (5,5′-dithiodisalicylato titanocene), whose structure was determined by X-ray diffraction analysis.Graphical abstractThe reaction mechanism of alcohol catalyzed synthesis of titanocene in the presence of sodium hydroxide was studied, and the pH value of the reaction could be widened when compared with the previous method. A macrocyclic titanocene, whose structure was determined by X-ray analysis, was prepared by the method.Research highlights► The reaction mechanism catalyzed synthesis of titanocene in the presence of sodium hydroxide was studied, and the pH value of the reaction could be widened when compared with the previous method. ► Titanocene complexes can obtain under normal temperature; no anhydrous organic solvents and insert gas are required. ► A macrocylic titanocene, whose structure was determined by X-ray analysis, was prepared by the method.

Formation of a novel hexanuclear ZrIV cage compound with bridging chelating ligand: [(CpZr)6(μ-O2C-C6H2Cl2-2-O)9(OH2)3]·H2O

Co-reporter:Jinling Li, Ziwei Gao, Li Han, Lingxiang Gao, Guofang Zhang, Wayne Tikkanen

Journal of Organometallic Chemistry 2010 695(15–16) pp: 1848-1851

Publication Date(Web):

DOI:10.1016/j.jorganchem.2010.04.035

Synthesis and characterization of novel four-arm star PDMAEMA-stabilized colloidal silver nanoparticles

Co-reporter:Huaming Sun;Lin Yang;Lingxiang Gao;Xushe Lv

Colloid and Polymer Science 2010 Volume 288( Issue 18) pp:1713-1722

Publication Date(Web):2010 December

DOI:10.1007/s00396-010-2290-y

Spontaneous formation and efficient stabilization of colloidal silver nanoparticles were achieved in aqueous four-arm star poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) solution at ambient temperature in the absence of any other reducing agent. In this reaction, four-arm star PDMAEMA acted as both reducing and stabilizing agents for silver nanoparticles. More importantly, four-arm star PDMAEMA is a tertiary-amine-containing star homopolymer, which shows that the scope of the reducing and stabilizing agents for metal nanoparticles can be extended from the general homopolymers and the block copolymers to the water-soluble simple tertiary-amine-containing star homopolymers. Fourier transform infrared, UV–vis absorption spectroscopy, and transmission electron microscopy were used to characterize the synthetic silver nanoparticles. A plausible mechanism for the formation of silver nanoparticles was proposed in the presence of linear and star PDMAEMA homopolymers. Moreover, the size of the resultant silver nanoparticles can be easily tuned by changing the concentrations of AgNO3.

Facile method for fabricating titania spheres for chromatographic packing

Co-reporter:Jianbo Yin, Ling He, Ziwei Gao, Lingxiang Gao, Bing Wang

Materials Letters 2009 Volume 63(Issue 26) pp:2191-2193

Publication Date(Web):31 October 2009

DOI:10.1016/j.matlet.2009.07.025

Titania (TiO2) spheres were fabricated by a solvent evaporation process in which anhydrous ethanol was used as the only solvent. This is a simple and novel route for the fabrication of TiO2 spheres. The spheres have a narrow particle size distribution and an average diameter of approximately 1.0 µm. The crystal structure of the prepared spheres was improved by high-temperature processing. A possible mechanism for the formation and growth of the spheres is proposed in which titanic acid molecules react with each other through hydroxyl condensation to form primary TiO2 particles. These aggregate and increase in size by surface reaction, and finally form spheres.

Crystal structural characterization of three chlorosalicylato titanocene compounds

Co-reporter:Jinling Li;Yani Li;Fang Xu;Lingxiang Gao

Structural Chemistry 2009 Volume 20( Issue 5) pp:883-890

Publication Date(Web):2009 October

DOI:10.1007/s11224-009-9487-z

Three chlorosalicylato titanocene compounds, namely [(MeCp)2Ti(O,O′)(OCC6H3-5-Cl)]2 (1), [(MeCp)2Ti(O,O′)(OCC6H2-3,5-Cl2)] (2) and [(MeCp)2Ti(O,O′)(OCC6H-3,5,6-Cl3)] (3) have been synthesized via the reaction of (MeCp)2TiCl2 [MeCp = η5-(CH3)C5H4] with the corresponding substituted chlorosalicylic acids in aqueous-organic systems in high yields and characterized by elemental analysis, IR and 1H NMR spectra. Single-crystal X-ray diffraction analysis shows that geometries at titanium (IV) atoms are distorted tetrahedrons and the exhibited frameworks are constructed through weak interactions, which are H-bonding, π–π stacking and C–H···π interactions. Additional weak interactions, such as Cl···Cl interactions in compound 1, are also present, which help to form and stabilize crystalline materials. It is noticeable that the discriminating framework structures of three compounds due to their weak interactions existing conspicuous changes which result from the number of chlorine atoms on substituted chlorosalicylates.

Synthesis and Structural Characterization of Substituted Salicylate Titanocene Complexes: Three Supramolecular Frameworks Determined by Weak Interactions

Co-reporter:Jinling Li;Caiyun Zhang;Lingxiang Gao

Journal of Chemical Crystallography 2009 Volume 39( Issue 9) pp:623-631

Publication Date(Web):2009 September

DOI:10.1007/s10870-009-9537-9

Based on the reaction between Cp2TiCl2 and substituted salicylic acids in the presence of β-cyclodextrin polymer (β-CDP), three four-coordinated titanocene complexes [(η5-C5H5)2Ti(S,O′)(OCC6H4)·(C6H6)0.5] (1), [(η5-C5H5)2Ti{(O,O′)(3,5-Cl2-OCC6H2)}] (2) and [(η5-C5H5)2Ti{(O,O′)(3,5-(NO2)2-OCC6H2)}] (3) were synthesized in high yields and their crystal structures have been determined by single-crystal X-ray diffraction. The structure of 1 has a Monoclinic space group P21/c with a = 8.313(3) Å, b = 9.960(4) Å, c = 22.330(8) Å, β = 111.856(11)° and Z = 4. The structure of 2 has a Monoclinic space group P21/c with a = 8.0577(13) Å, b = 8.9022(14) Å, c = 21.977(4) Å, β = 96.298(3)° and Z = 4. The structure of 3 has a Triclinic space group P-1 with a = 8.1687(11) Å, b = 8.3027(11) Å, c = 12.7164(17) Å, α = 102.930(2)°, β = 100.479(2)°, γ = 95.458(2)° and Z = 2. Each of the complexes exhibits a three-dimensional framework constructed through weak interactions, which are hydrogen bonding, π–π stacking and C–H···π interactions. It was found that the variation of the substituted salicylate ligands affect the weak interactions as well as the specific framework structure that forms.

Synthesis of 4-arm methyl methacrylate star polymer by atom transfer radical polymerization

Co-reporter:Huaming Sun;Lin Yang;Lingxiang Gao

Frontiers of Chemistry in China 2009 Volume 4( Issue 1) pp:89-92

Publication Date(Web):2009 March

DOI:10.1007/s11458-009-0010-2

The synthesis of 4-arm methyl methacrylate star polymer had been achieved successfully by atom transfer radical polymerization using CuCl as catalyst, 2, 2′-bipyridyl as ligand and pentaerythritol tetrakis (2-bromoisobutyrate) as the initiator. The star polymer was characterized by 1H-NMR and GPC, by which the precise 4-arm structure of the PMMA was confirmed.

Preparation of organozirconium aromatic compounds in mixed aqueous-organic solvents: X-ray structures of [Cp2ZrCl(μ2-O′,O′′C-C6H5)], [(CpZr)3(μ2-O′,O′′C-C6H3Cl2)3(μ3-OH)(μ2-OH)3](Cl2C6H3COO)2, and [(CpZr)3(μ2-O′,O′′C-C6H4Cl)3(μ3-OH)(μ2-OH)3]Cl2·CH2Cl2

Co-reporter:Jinling Li, Ziwei Gao, Li Han, Lingxiang Gao, Caiyun Zhang, Wayne Tikkanen

Journal of Organometallic Chemistry 2009 694(21) pp: 3444-3451

Publication Date(Web):

DOI:10.1016/j.jorganchem.2009.06.032

Syntheses and supramolecular structures of two 5-nitrosalicylate titanocene complexes

Co-reporter:Ziwei Gao;Caiyun Zhang;Mingyuan Dong;Lingxiang Gao;Guofang Zhang;Zhaotie Liu;Gaofeng Wang;Denghui Wu

Applied Organometallic Chemistry 2006 Volume 20(Issue 2) pp:

Publication Date(Web):2 DEC 2005

DOI:10.1002/aoc.1022

Two 4-coordinated titanocene complexes, [(η⁵-C₅H₅)₂Ti(O,O′)(5-NO₂-OCC₆H₃)] (I) and [(η⁵-C₅H₅)₂Ti(2-OH-5-NO₂-O₂CC₆H₃)₂] (II), have been synthesized by reaction of Cp₂TiCl₂ and 5-nitrosalicylic acid in aqueous media. Single-crystal X-ray analyses of I and II display the mononuclear forms of Ti^IV, and geometries at titanium atoms are distorted tetrahedrons, while the coordination environment at Ti^IV in complex I is different from that in complex II. Crystallographic characterization revealed that each of the complexes exhibits a three-dimensional framework constructed through weak interactions, which are H-bonding, π–π stacking and C–H·π interactions, but they differ greatly when forming the three-dimensional network structure in both complexes. The results show that the dramatic change of conditions has great effect on the molecular structure of 5-nitrosalicylate titanocene, thereby significantly influencing the weak interactions and the specific framework structure. Copyright © 2005 John Wiley & Sons, Ltd.