Palladium(I) Coordination Polymers with Unsaturated Dicarboxylic Acids with Stable Paramagnetic Centers

• Published in: Russian journal of coordination chemistry Vol. 47; no. 10; pp. 707 - 716
• Main Authors: Efimenko, I. A., Efimov, N. N., Erofeeva, O. S., Demina, L. I., Simonenko, N. P., Churakov, A. V., Minin, V. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.10.2021; Springer Nature B.V
• Subjects: Chemistry; Chemistry and Materials Science; Clusters; Coordination polymers; Dicarboxylic acids; Fumaric acid; Infrared spectroscopy; Inorganic Chemistry; Maleic acid; Palladium; Physical Chemistry; Redox reactions; Solvation; Thermogravimetric analysis; Water chemistry; X-ray diffraction; Pd(I) dicarboxylate polymers; stable unpaired electrons
• ISSN: 1070-3284; 1608-3318
• DOI: 10.1134/S1070328421090037

Palladium(I) coordination polymers with unsaturated dicarboxylic acids, {[ cis -Pd(C 4 H 2 O 4 )(H 2 O)]·(H 2 O)} n ( I ) (maleic acid), {[ cis -Pd(C 5 H 4 O 4 )(H 2 O)]·2H 2 O} n ( II ) (citraconic acid), and {[ trans -Pd(C 4 H 2 O 4 )(H 2 O)]·(H 2 O)} n ( III ) (fumaric acid) with stable paramagnetic centers in the polymer matrix were synthesized for the first time. According to IR and ESR spectroscopy data (determining the number of paramagnetic centers) and results of thermogravimetric analysis, the building blocks of I – III are, at least, tetranuclear Pd(I) clusters, in which palladium atoms are linked by bridging carboxylate groups. Each carboxylate group is coordinated via only one O atom, while the second O atom is linked to the nearest palladium atom of the neighboring cluster, thus giving a multidimensional coordination polymer. The coordination sphere of each Pd(I) atom in the cluster is completed by a water molecule and Pd–Pd bond. Heating of I – III results in the loss of solvation water molecules as the first stage. Above 100°C, the onset of removal of the coordinated water molecules is accompanied by complete decomposition of the complexes. On treatment of I with CH 3 CN in methanol, redox reaction takes place, in which complex I disproportionates to give Pd(II) complex and Pd(0) to give [Pd(HOOC–CH–CH(CH 3 O)(CH 3 CN) 2 ] ( IV ) (CIF file CCDC no. 2039147).