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Šorm D, Blahut J, Bashta B, Císařová I, Vrbková E, Vyskočilová E, Sedláček J. Complex isomerism influencing the textural properties of organometallic [Cu(salen)] porous polymers: paramagnetic solid-state NMR characterization and heterogeneous catalysis. Dalton Trans 2024; 53:12162-12175. [PMID: 38963296 DOI: 10.1039/d4dt01305k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Although organometallic porous polymer networks are recognized as promising heterogeneous catalysts, the relationship between ligand/monomer geometry and network parameters is usually not well understood due to the lack of atom-resolved characterization methods for the amorphous network matrix. In this work, a series of copper(II) salen-type metal complexes was synthesized, using trans- and cis-1,2-diaminocyclohexane segments, and thoroughly characterized by single-crystal X-ray diffraction and solution- and solid-state NMR spectroscopy. Terminal ethynyl groups of the complexes were then transformed into polyacetylene chains by coordination chain-growth homopolymerization, resulting in highly porous (458-655 m2 g-1) organometallic polymer networks with a copper(II) ion content of about 12 wt%. The presence of paramagnetic copper(II) moieties in these complexes and respective polymer networks required the application of tailored NMR techniques, which together with X-ray crystallography and DFT calculations of the paramagnetic NMR shifts made it possible to investigate the differences in the complex geometry in liquid, powder and crystalline form and compare it with the complex geometry in polymer networks. All prepared organometallic polymer networks were also tested as heterogeneous catalysts for styrene oxidation with uncommonly high substrate conversions and compared with their low-molecular-weight analogues. The high reusability of such heterogeneous polymer-based catalysts was also proven.
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Affiliation(s)
- David Šorm
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, Prague 2, 128 43, Czech Republic.
| | - Jan Blahut
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo náměstí 542/2, Prague 6, 160 00, Czech Republic.
| | - Bogdana Bashta
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, Prague 2, 128 43, Czech Republic.
| | - Ivana Císařová
- Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, Prague 2, 128 43, Czech Republic
| | - Eva Vrbková
- Department of Organic Technology, University of Chemistry and Technology Prague, Technická 5, Prague 6, 166 28, Czech Republic
| | - Eliška Vyskočilová
- Department of Organic Technology, University of Chemistry and Technology Prague, Technická 5, Prague 6, 166 28, Czech Republic
| | - Jan Sedláček
- Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, Prague 2, 128 43, Czech Republic.
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2
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Zhao Z, Geng Y, Song J, Cui X. Cu
I
/Ag
I
‐containing coordination compounds as advanced catalysts for selective oxidation of styrene to benzaldehyde. Appl Organomet Chem 2022. [DOI: 10.1002/aoc.6770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Zi‐Qiu Zhao
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry and College of Chemistry, Jilin University Changchun Jilin
| | - Ying Geng
- Department of Chemistry North University of China Taiyuan Shanxi PR China
| | - Jiang‐Feng Song
- Department of Chemistry North University of China Taiyuan Shanxi PR China
| | - Xiao‐Bing Cui
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry and College of Chemistry, Jilin University Changchun Jilin
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3
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Synthesis and molecular structure of half-sandwich ruthenium(II) complexes containing pyrazolyl ligands: Solvent induced geometrical change in κ2-scorpionate supported complex. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.132005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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4
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Unprecedented Mechanochemical Synthesis and Heterogenization of a C-Scorpionate Au(III) Catalyst for Microwave-Assisted Biomass Valorization. NANOMATERIALS 2022; 12:nano12030362. [PMID: 35159707 PMCID: PMC8839393 DOI: 10.3390/nano12030362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/14/2022] [Accepted: 01/19/2022] [Indexed: 11/17/2022]
Abstract
The transformation of biomass, a carbon resource presenting a huge potential to produce valuable chemicals, requires the search for sustainable catalytic routes. This work proposes the microwave-assisted oxidation of biomass -derived substrates, such as glycerol and the furfural derivatives 5-(hydroxymethyl)furfural (HMF) and 5-hydroxymethyl-2-furancarboxylic acid (HFCA), using the C-scorpionate dichloro-gold(III) complex [AuCl2(κ2-Tpm)]Cl (Tpm = HCpz3; pz = pyrazol-1-yl) as a catalyst, as prepared and supported on graphene, in solvent-free conditions. The unprecedented application of a mechanochemical procedure (in a planetary ball mill, in solid state) to synthesize a C-scorpionate complex, the [AuCl2(κ2-Tpm)]Cl, is disclosed. The immobilization of [AuCl2(κ2-Tpm)]Cl on graphene was performed using different methods, including some (e.g., microwave irradiation and liquid assisted grinding) for the first time. The structural properties and the performance of the prepared catalytic materials are presented and discussed.
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5
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Su F, Peng H, Yin H, Luo C, Zhu L, Zhong W, Mao L, Yin D. Biowaste-derived hydrochar microspheres: Realizing metal-free visible-light photocatalytic oxidation of amines. J Catal 2021. [DOI: 10.1016/j.jcat.2021.09.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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6
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Petrenko YP, Piasta K, Khomenko DM, Doroshchuk RO, Shova S, Novitchi G, Toporivska Y, Gumienna-Kontecka E, Martins LMDRS, Lampeka RD. An investigation of two copper(ii) complexes with a triazole derivative as a ligand: magnetic and catalytic properties. RSC Adv 2021; 11:23442-23449. [PMID: 35479774 PMCID: PMC9036593 DOI: 10.1039/d1ra03107d] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/24/2021] [Indexed: 12/13/2022] Open
Abstract
Two new copper(ii) complexes [Cu2(L)2(OAc)2(H2O)2] (1) (L = 3-methyl-5-pyridin-2-yl-1,2,4-triazole) and [CuL2] (2) were prerared and thoroughly studied. The complexes are able to selectively catalyze the oxidation of styrene towards benzaldehyde and of cyclohexane to KA oil. The 2D coordination polymer 1 showed an antiferromagnetic behaviour attributed to the intrachain magnetic coupling.
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Affiliation(s)
- Yuliia P Petrenko
- Department of Chemistry, Taras Shevchenko National University of Kyiv Volodymyrska Street, 64/13 Kyiv 01601 Ukraine
| | - Karolina Piasta
- Faculty of Chemistry, University of Wroclaw F. Joliot-Curie 14 50-383 Wroclaw Poland
| | - Dmytro M Khomenko
- Department of Chemistry, Taras Shevchenko National University of Kyiv Volodymyrska Street, 64/13 Kyiv 01601 Ukraine
| | - Roman O Doroshchuk
- Department of Chemistry, Taras Shevchenko National University of Kyiv Volodymyrska Street, 64/13 Kyiv 01601 Ukraine
| | - Sergiu Shova
- "Petru Poni" Institute of Macromolecular Chemistry, Laboratory of Inorganic Polymers Aleea Grigore Ghica Voda No. 41A RO-700487 Iasi Romania
| | - Ghénadie Novitchi
- Laboratoire National des Champs Magnétiques Intenses, UPR CNRS 3228, Université Grenoble-Alpes 25 rue des Martyrs, B.P. 166 38042 Grenoble Cedex 9 France
| | - Yuliya Toporivska
- Faculty of Chemistry, University of Wroclaw F. Joliot-Curie 14 50-383 Wroclaw Poland
| | | | - Luísa M D R S Martins
- Centro de Química Estrutural, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa Av. Rovisco Pais 1049-001 Lisboa Portugal
| | - Rostyslav D Lampeka
- Department of Chemistry, Taras Shevchenko National University of Kyiv Volodymyrska Street, 64/13 Kyiv 01601 Ukraine
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7
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Andrade MA, Martins LMDRS. Selective Styrene Oxidation to Benzaldehyde over Recently Developed Heterogeneous Catalysts. Molecules 2021; 26:1680. [PMID: 33802853 PMCID: PMC8002843 DOI: 10.3390/molecules26061680] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/11/2021] [Accepted: 03/15/2021] [Indexed: 11/16/2022] Open
Abstract
The selective oxidation of styrene under heterogeneous catalyzed conditions delivers environmentally friendly paths for the production of benzaldehyde, an important intermediate for the synthesis of several products. The present review explores heterogeneous catalysts for styrene oxidation using a variety of metal catalysts over the last decade. The use of several classes of supports is discussed, including metal-organic frameworks, zeolites, carbon materials and silicas, among others. The studied catalytic systems propose as most used oxidants tert-butyl hydroperoxide, and hydrogen peroxide and mild reaction conditions. The reaction mechanism proceeds through the generation of an intermediate reactive metal-oxygen species by catalyst-oxidant interactions. Overall, most of the studies highlight the synergetic effects among the metal and support for the activity and selectivity enhancement.
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Affiliation(s)
| | - Luísa M. D. R. S. Martins
- Centro de Química Estrutural and Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbn, Portugal;
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Matias IAS, Ribeiro APC, Ferraria AM, do Rego AMB, Martins LMDRS. Catalytic Performance of a Magnetic Core-Shell Iron(II) C-Scorpionate under Unconventional Oxidation Conditions. NANOMATERIALS 2020; 10:nano10112111. [PMID: 33114194 PMCID: PMC7690781 DOI: 10.3390/nano10112111] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 10/16/2020] [Accepted: 10/21/2020] [Indexed: 11/16/2022]
Abstract
For the first time, herein is reported the use of a magnetic core-shell support for a C-scorpionate metallic complex. The prepared hybrid material, that consists on the C-scorpionate iron(II) complex [FeCl2{κ3-HC(pz)3}] (pz, pyrazolyl) immobilized at magnetic core-shell particles (Fe3O4/TiO2), was tested as catalyst for the oxidation of secondary alcohols using the model substrate 1-phenylethanol. Moreover, the application of alternative energy sources (e.g., ultrasounds, microwaves, mechanical or thermal) for the peroxidative alcohol oxidation using the magnetic heterogenized iron(II) scorpionate led to different/unusual outcomes that are presented and discussed.
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Affiliation(s)
- Inês A. S. Matias
- Centro de Química Estrutural and Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal;
| | - Ana P. C. Ribeiro
- Centro de Química Estrutural and Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal;
- Correspondence: (A.P.C.R.); (L.M.D.R.S.M.); Tel.: +351-218419389 (L.M.D.R.S.M.)
| | - Ana M. Ferraria
- BSIRG, IBB-Institute for Bioengineering and Biosciences, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; (A.M.F.); (A.M.B.d.R.)
| | - Ana M. Botelho do Rego
- BSIRG, IBB-Institute for Bioengineering and Biosciences, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal; (A.M.F.); (A.M.B.d.R.)
| | - Luísa M. D. R. S. Martins
- Centro de Química Estrutural and Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal;
- Correspondence: (A.P.C.R.); (L.M.D.R.S.M.); Tel.: +351-218419389 (L.M.D.R.S.M.)
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9
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Supported Palladium Nanocatalysts: Recent Findings in Hydrogenation Reactions. Processes (Basel) 2020. [DOI: 10.3390/pr8091172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Catalysis has witnessed a dramatic increase on the use of metallic nanoparticles in the last decade, opening endless opportunities in a wide range of research areas. As one of the most investigated catalysts in organic synthesis, palladium finds numerous applications being of significant relevance in industrial hydrogenation reactions. The immobilization of Pd nanoparticles in porous solid supports offers great advantages in heterogeneous catalysis, allowing control of the major factors that influence activity and selectivity. The present review deals with recent developments in the preparation and applications of immobilized Pd nanoparticles on solid supports as catalysts for hydrogenation reactions, aiming to give an insight on the key factors that contribute to enhanced activity and selectivity. The application of mesoporous silicas, carbonaceous materials, zeolites, and metal organic frameworks (MOFs) as supports for palladium nanoparticles is addressed.
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10
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Dobrov A, Fesenko A, Yankov A, Stepanenko I, Darvasiová D, Breza M, Rapta P, Martins LMDRS, Pombeiro AJL, Shutalev A, Arion VB. Nickel(II), Copper(II) and Palladium(II) Complexes with Bis-Semicarbazide Hexaazamacrocycles: Redox-Noninnocent Behavior and Catalytic Activity in Oxidation and C-C Coupling Reactions. Inorg Chem 2020; 59:10650-10664. [PMID: 32649194 DOI: 10.1021/acs.inorgchem.0c01119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nickel(II), copper(II), and palladium(II) complexes MLH, where M = Ni (1), Cu (2), Pd (3), and MLOMe, where M = Ni (4), Cu (5), Pd (6), have been prepared by reactions of NiCl2·6H2O, Cu(OAc)2·H2O, and PdCl2(MeCN)2 with 14-membered bis-semicarbazide hexaazamacrocycles H2LH and H2LOMe in dimethylformamide (DMF). The compounds were characterized by elemental analysis, ESI mass spectrometry, IR, UV-vis, and 1D (1H, 13C) and 2D (1H-1H COSY, 1H-1H TOCSY, 1H-1H NOESY, 1H-13C HSQC, 1H-13C HMBC) NMR spectra (1, 3, 4, and 6), and X-ray diffraction (2, 4-6). The complexes with MIIN4 coordination environment have S = 0, 1/2, 0 ground states for Ni, Cu, and Pd, respectively. The electrochemical behavior of 1-6 was investigated in detail. The electronic structures of 1e-oxidized species were studied by EPR, UV-vis-NIR spectroelectrochemistry, and DFT calculations, indicating the redox-noninnocent behavior of the ligands. Compounds 1-6 were tested in the oxidation of styrene and C-C coupling (Henry and Knoevenagel condensations). Compounds 2 and 5 selectively catalyze the microwave-assisted oxidation of neat styrene to benzaldehyde (up to 88% yield), whereas the 1 and 4 catalytic systems afforded up to 99% β-nitroethanol yield with an appreciable diastereoselectivity toward the formation of the anti isomer.
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Affiliation(s)
- Anatolie Dobrov
- University of Vienna, Institute of Inorganic Chemistry, Währinger Strasse 42, A-1090 Vienna, Austria.,Universität Wien, Fakultät für Chemie, Institut für Biophysikalische Chemie, Altanstraße 14, 1090 Wien, Austria
| | - Anastasia Fesenko
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky Ave., 119991 Moscow, Russian Federation
| | - Alexander Yankov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky Ave., 119991 Moscow, Russian Federation
| | - Iryna Stepanenko
- University of Vienna, Institute of Inorganic Chemistry, Währinger Strasse 42, A-1090 Vienna, Austria
| | - Denisa Darvasiová
- Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-81237 Bratislava, Slovak Republic
| | - Martin Breza
- Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-81237 Bratislava, Slovak Republic
| | - Peter Rapta
- Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-81237 Bratislava, Slovak Republic
| | - Luísa M D R S Martins
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Armando J L Pombeiro
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Anatoly Shutalev
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky Ave., 119991 Moscow, Russian Federation
| | - Vladimir B Arion
- University of Vienna, Institute of Inorganic Chemistry, Währinger Strasse 42, A-1090 Vienna, Austria
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11
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Ahmad SM, Mestre AS, Neng NR, Ania CO, Carvalho AP, Nogueira JMF. Carbon-Based Sorbent Coatings for the Determination of Pharmaceutical Compounds by Bar Adsorptive Microextraction. ACS APPLIED BIO MATERIALS 2020; 3:2078-2091. [PMID: 35025329 DOI: 10.1021/acsabm.9b01206] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thirteen carbon materials comprising commercial activated carbons and lab-made materials (activated carbons, hydrochars, and low-T and high-T activated hydrochars) were assayed as sorbent coatings in bar adsorptive microextration (BAμE) to monitor trace levels of ten common pharmaceutical compounds (PhCs) in environmental water matrices including surface water, seawater, tap water, and wastewater. Polar and nonpolar pharmaceuticals were selected, sulfamethoxazole, triclosan, carbamazepine, diclofenac, mefenamic acid, 17-α-ethinylestradiol, 17-β-estradiol, estrone, gemfibrozil, and clofibric acid, as model compounds to cover distinct therapeutic classes. Despite having a less-developed porosity, data showed that "in-house" prepared low-T activated hydrochars, obtained from carbohydrates and an eutectic salt mixture at low temperature (i.e., 180 °C) and autogenerated pressure, compete with the best commercial activated carbons for this particular application. The combination of a micro and mesopore network with a rich oxygen-based surface chemistry yielding an acidic nature allowed these low-T activated hydrochars to present the best overall recoveries (between 20.9 and 82.4%) for the simultaneous determination of the ten target PhCs with very distinct chemical properties using high performance liquid chromatography-diode array detection (HPLC-DAD).
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Affiliation(s)
- Samir M Ahmad
- Centro de Quı́mica Estrutural and Departamento de Quı́mica e Bioquı́mica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Ana S Mestre
- Centro de Quı́mica Estrutural and Departamento de Quı́mica e Bioquı́mica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Nuno R Neng
- Centro de Quı́mica Estrutural and Departamento de Quı́mica e Bioquı́mica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Conchi O Ania
- CNRS, CEMHTI UPR3079, University of Orléans, F-45071 Orléans, France
| | - Ana P Carvalho
- Centro de Quı́mica Estrutural and Departamento de Quı́mica e Bioquı́mica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - José M F Nogueira
- Centro de Quı́mica Estrutural and Departamento de Quı́mica e Bioquı́mica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
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12
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Onisuru OR, Oseghale CO, Meijboom R. In situ replacement of Cu-DEN: an approach for preparing a more noble metal nanocatalyst for catalytic use. NEW J CHEM 2020. [DOI: 10.1039/d0nj04381h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The advantage of dendritic monodisperse macromolecules’ dual templating ability was useful in the formation of silica-supported copper nanoparticles Cun@SiO2NPs.
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Affiliation(s)
- Oluwatayo Racheal Onisuru
- Research Centre for Synthesis and Catalysis
- Department of Chemical Sciences
- University of Johannesburg
- Johannesburg 2006
- South Africa
| | - Charles O. Oseghale
- Research Centre for Synthesis and Catalysis
- Department of Chemical Sciences
- University of Johannesburg
- Johannesburg 2006
- South Africa
| | - Reinout Meijboom
- Research Centre for Synthesis and Catalysis
- Department of Chemical Sciences
- University of Johannesburg
- Johannesburg 2006
- South Africa
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13
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Hydrosoluble Complexes Bearing Tris(pyrazolyl)methane Sulfonate Ligand: Synthesis, Characterization and Catalytic Activity for Henry Reaction. Catalysts 2019. [DOI: 10.3390/catal9070611] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The catalytic activity of the water-soluble scorpionate coordination compounds [Cu(-NN’O-Tpms)2] (1), [Mn(Tpms)2] (2) and Li[FeCl2(-NN’N’’-Tpms)] (3) [Tpms = tris(pyrazolyl)-methane sulfonate, O3SC(pz)3], were studied towards the (Henry) reaction between benzaldehyde and nitromethane or nitroethane in aqueous medium to afford, respectively, 2-nitro-1-phenylethanol or 2-nitro-1-phenylpropanol, the latter in the syn and the anti diastereoisomeric forms. Complex 1 exhibited the highest activity under the optimum experimental conditions and was used to broaden the scope of the reaction to include several aromatic aldehydes achieving yields up to 94%.
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