Cu(I) camphor coordination polymers: Synthesis and study of the catalytic activity for cyclization of 4‐pentyn‐1‐oic acid |
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| Authors: | Tiago A Fernandes Adelino M Galvão Ana M Botelho do Rego M Fernanda N N Carvalho |
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| Institution: | 1. Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, , 1049‐001 Lisboa, Portugal;2. Centro de Química‐Física Molecular (CQFM) and Institute of Nanoscience and Nanotechnology (IN), Instituto Superior Técnico, Universidade de Lisboa, , 1049‐001 Lisboa, Portugal |
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| Abstract: | The number of CuCl units per camphor ligand in {CuCl}2L]n was extended to three or four in {CuCl}3L]n ( 2 ) or {CuCl}4L]n ( 1 ). The Hartree‐Fock ab initio calculations support the polymeric structure of 1 and 2 that catalyze the cyclization of 4‐pentyn‐1‐oic acid ( A ) forming 5‐methylenedihydrofuran‐2(3H)‐one ( B ) and/or 2‐methyl‐5‐oxotetrahydrofuran‐2‐ylpent‐4‐ynoate ( C ). The catalytic activity of 1 , 2 and other polynuclear Cu(I) complexes ( 3–5 ) was evaluated under solvent free conditions and/or solution. In the absence of solvent, catalyst 2 displays the highest activity and selectivity (75.8/23.1, C to B ratio, at 5.4% loading) while 4 reaches the highest level of A → B conversion (97.5 %) in solution. Selected reactions were followed by NMR and the kinetic constants calculated. A mechanism is proposed based on the equations used for the calculations. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3316–3323 |
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| Keywords: | alkynoic acid cyclization camphor derived ligands camphor ligands copper coordination polymers Cu(I) Hartree‐Fock ab initio calculations lactones solvent free catalysis |
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