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Dehmel M, Vass V, Prock L, Görls H, Kretschmer R. Synthesis and Coordination Chemistry of 3,4-Ethylene-Bridged 1,1,2,5-Tetrasubstituted Biguanides. Inorg Chem 2020; 59:2733-2746. [PMID: 32048512 DOI: 10.1021/acs.inorgchem.9b03093] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis of 3,4-ethylene-bridged 1,1,2,5-tetrasubstituted biguanides is reported, which are accessible by three alternative routes. Exemplary molecular structures of the ligand and an observed side product have been elucidated by X-ray diffraction analysis. Mono- and dinuclear complexes of the biguanide in both its neutral and monoanionic forms were obtained, including examples of aluminum, copper, magnesium, potassium, tin, and zinc, indicating a versatile coordination behavior, as evidenced by means of single-crystal X-ray diffraction analysis.
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Affiliation(s)
- Maximilian Dehmel
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743 Jena, Germany
| | - Valentin Vass
- University of Regensburg, Institute of Inorganic Chemistry, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Lukas Prock
- University of Regensburg, Institute of Inorganic Chemistry, Universitätsstrasse 31, 93053 Regensburg, Germany
| | - Helmar Görls
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743 Jena, Germany
| | - Robert Kretschmer
- Institute of Inorganic and Analytical Chemistry (IAAC), Friedrich Schiller University Jena, Humboldtstraße 8, 07743 Jena, Germany.,Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena Philosophenweg 7, 07743 Jena, Germany
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Garcés A, Sánchez-Barba LF, Fernández-Baeza J, Otero A, Fernández I, Lara-Sánchez A, Rodríguez AM. Organo-Aluminum and Zinc Acetamidinates: Preparation, Coordination Ability, and Ring-Opening Polymerization Processes of Cyclic Esters. Inorg Chem 2018; 57:12132-12142. [PMID: 30212185 DOI: 10.1021/acs.inorgchem.8b01723] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The reaction of the highly sterically demanding NNN'-heteroscorpionate protioligands pbptamd-H, tbptamd-H, and phbptamd-H (a) and the low sterically hindered analogs pbpamd-H, tbpamd-H, and phbpamd-H (b), with 1 equiv of AlR3 (R = Me, Et) proceed in high yields to give two families of complexes: the mononuclear dialkyl aluminum bidentate-acetamidinates [AlR2(κ2- N' N')] (κ2- N' N' = pbptamd, R = Me 1, Et 2; tbptamd, R = Me 3, Et 4; phbptamd, R = Me 5, Et 6) and the monodentate-acetamidinates [AlR2(κ2- NN')] (κ2- NN' = tbpamd, R = Me 7; phbpamd, R = Me 8, Et 9). In complexes 7-9, the presence of two possible CH-NH tautomers as low extended π-N-C-N'(sp2)-Al and high extended π-HN-C2-N'(sp2)-Al complexes, respectively, could be identified. Moreover, the reaction of aluminum dimethyls 7 and 8 with ZnMe2 afforded the isolation of the more stable scorpionate zinc monoalkyls [Zn(Me)(κ3- NNN')] ( NNN' = tbpamd 10 and phbpamd 11), through a very unusual ligand exchange process, involving a zinc-to-aluminum transmetalation of an alkyl group. The X-ray crystal structures of 1, 3, 7, and 8, as well as that of 11, confirmed unambiguously the different κ2-arrangements proposed for bi- or monodentate acetamidinate dialkyls 1-6 and 7-9, respectively, the presence of NH tautomer in 7 and 8, and a κ3- NNN' coordination in monoalkyl 11. Density functional theory calculations were used to explore the three different favored κ2-arrangements found in acetamidinate aluminum dialkyls 1-9, the relative stability of both CH-NH tautomers, and the ligand transfer reaction leading to the formation of κ3- NNN' zinc monoalkyls 10 and 11. Interestingly, dialkyls 1, 5, 7, and 8 can act as highly efficient single-component living initiators for the ring-opening polymerization of ε-caprolactone and rac-lactide in mild conditions after hours. These initiators efficiently mediated the immortal polymerization in the presence of excess of benzyl alcohol (up to 20 equiv), as evidenced by the narrow dispersity values and the good agreement between the experimental Mn values and monomer/benzyl alcohol ratios. In addition, the most sterically hindered initiator, 5, exhibits enhanced levels of heteroselectivity on the produced PLAs, reaching Ps values up to 0.70.
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Affiliation(s)
- Andrés Garcés
- Departamento de Biología y Geología, Física y Química Inorgánica , Universidad Rey Juan Carlos, Móstoles , 28933 Madrid , Spain
| | - Luis F Sánchez-Barba
- Departamento de Biología y Geología, Física y Química Inorgánica , Universidad Rey Juan Carlos, Móstoles , 28933 Madrid , Spain
| | - Juan Fernández-Baeza
- Universidad de Castilla-La Mancha , Departamento de Química Inorgánica, Orgánica y Bioquímica, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Campus Universitario , 13071 Ciudad Real , Spain
| | - Antonio Otero
- Universidad de Castilla-La Mancha , Departamento de Química Inorgánica, Orgánica y Bioquímica, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Campus Universitario , 13071 Ciudad Real , Spain
| | - Israel Fernández
- Departamento de Química Orgánica I, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Facultad de Ciencias Químicas , Universidad Complutense de Madrid , 28040 Madrid , Spain
| | - Agustín Lara-Sánchez
- Universidad de Castilla-La Mancha , Departamento de Química Inorgánica, Orgánica y Bioquímica, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Campus Universitario , 13071 Ciudad Real , Spain
| | - Ana M Rodríguez
- Universidad de Castilla-La Mancha , Departamento de Química Inorgánica, Orgánica y Bioquímica, Centro de Innovación en Química Avanzada (ORFEO-CINQA), Campus Universitario , 13071 Ciudad Real , Spain
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Bayram M, Bläser D, Wölper C, Schulz S. Synthesis and X-ray Crystal Structure of Diimidosulfinate Transition Metal Complexes. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00407] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Melike Bayram
- Institute
of Inorganic Chemistry, University of Duisburg-Essen, Universitätsstr. 5-7, D-45117 Essen, Germany
| | - Dieter Bläser
- Institute
of Inorganic Chemistry, University of Duisburg-Essen, Universitätsstr. 5-7, D-45117 Essen, Germany
| | - Christoph Wölper
- Institute
of Inorganic Chemistry, University of Duisburg-Essen, Universitätsstr. 5-7, D-45117 Essen, Germany
| | - Stephan Schulz
- Institute
of Inorganic Chemistry, University of Duisburg-Essen, Universitätsstr. 5-7, D-45117 Essen, Germany
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