{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T17:52:53Z","timestamp":1791827573882,"version":"4.3.4"},"reference-count":36,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2024,2,17]],"date-time":"2024-02-17T00:00:00Z","timestamp":1708128000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>We have described a new route for the preparation of partially methylated polygalacturonic acid containing hydrolyzed (acidic) and unhydrolyzed (methyl esterified) carboxylate groups in a ratio of 1:1 (PGA, compound 1), and one of its basic FeIII\u2014salts (compound 2) with a ~1:2 FeIII:GA stoichiometry (GA means galacturonic acid and methylated galacturonic acid units). The partially hydrolyzed pectin was transformed into compound 1 with the use of double ion exchange with a strongly acidic macroreticular sulfonated styrene\u2013divinylbenzene copolymer as a hydrogen ion source. The reaction of compound 1 with FeCl3 resulted in compound 2. Compound 2 has a polymeric nature and contains binuclear FeIII(\u00b5-O)(\u00b5-OH)FeIII core units with two kinds of distorted octahedral iron geometries. The salt-forming acidic and methylated GA units of compound 1 are coordinated to FeIII centers in asymmetric bidentate-chelating and -bridging (via C=O group and glycosidic oxygen) modes, respectively. Two kinds of outer-sphere chloride anions were also detected by XPS in various chemical environments fixed by different sets of hydrogen bonds. We also observed a partial reduction of FeIII into FeII due to the ring-opening of the chain-end GA units of compound 1. This reaction provides a new route to determine the number of chain-ends in compound 2, and with the use of the number of GA units calculated from charge neutrality, the average length of these chains and the average molecular weight were also determined. The average molecular weight of the partially methylated polygalacturonic acid used in the industrial-scale production of commercial anti-anemic iron\u2013polygalacturonate agents was ~50,000 g\/mol. Compound 2 was also characterized by IR, M\u00f6ssbauer, and X-ray photoelectron spectroscopy, and magnetic susceptibility measurements. These results on the structure and average molecular weight of basic iron(III) polygalacturonate provide a tool to design Fe-PGA complexes with tuned iron-releasing properties.<\/jats:p>","DOI":"10.3390\/molecules29040890","type":"journal-article","created":{"date-parts":[[2024,2,21]],"date-time":"2024-02-21T05:42:46Z","timestamp":1708494166000},"page":"890","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Reaction of Partially Methylated Polygalacturonic Acid with Iron(III) Chloride and Characterization of a New Mixed Chloride\u2013Polygalacturonate Complex"],"prefix":"10.3390","volume":"29","author":[{"given":"L\u00e1szl\u00f3","family":"K\u00f3tai","sequence":"first","affiliation":[{"name":"HUN-REN Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tud\u00f3sok K\u00f6r\u00fatja 2, H-1117 Budapest, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K\u00e1roly","family":"L\u00e1z\u00e1r","sequence":"additional","affiliation":[{"name":"HUN-REN Centre for Energy Research, EKBI, Konkoly Thege Mikl\u00f3s \u00dat, 29-33, H-1121 Budapest, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7972-7509","authenticated-orcid":false,"given":"L\u00e1szl\u00f3 Ferenc","family":"Kiss","sequence":"additional","affiliation":[{"name":"HUN-REN Wigner Research Centre for Physics, H-1525 Budapest, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kl\u00e1ra","family":"Szentmih\u00e1lyi","sequence":"additional","affiliation":[{"name":"HUN-REN Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tud\u00f3sok K\u00f6r\u00fatja 2, H-1117 Budapest, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,2,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1007\/s12668-021-00879-6","article-title":"Anti-anemic activity of sodium, calcium, iron-Polygalacturonate in vivo in rabbits","volume":"2","author":"Minzanova","year":"2022","journal-title":"BioNanoScience"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"276","DOI":"10.1016\/j.carbpol.2018.02.007","article-title":"Design of polygalacturonate hydrogels using iron(II) as cross-linkers: A promising route to protect bioavailable iron against oxidation","volume":"188","author":"Lerbret","year":"2018","journal-title":"Carbohyd. 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