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カロリメトリーによるポリオキシメタレートの反応性,形成,溶解性

Hrafn Traustason¹, Nicola L Bell², Kiana Caranto³

¹Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States.

Journal of the American Chemical Society

|November 18, 2020

まとめ

カロリメトリー方法は,ポリオキシメタレート (POM) のエネルギー風景を明らかにします. 水酸化物ブリッジウラニル過酸化物POMはより安定しており,球形のPOMは車輪のような構造よりもエネルギー的に有利である可能性があります.

科学分野:

無機化学
材料科学
熱化学

背景:

ポリオックスメタラート (POM) は,多様な用途を持つ多用途のナノスケール材料です.
POMのエネルギー特性を理解することは,その合成と応用にとって極めて重要です.
以前の研究は,特定のPOM構造に焦点を当てており,包括的なエネルギー比較は欠けている.

研究の目的:

POMエネルギー景観を特徴付けるための室温カロメトリー方法を開発する.
6つのPOMの溶解エンタルピー (ΔHdiss),水性POMの形成エンタルピー (ΔHf,(aq),およびPOM結晶の形成エンタルピー (ΔHf,(c)) を決定する.
構造的な特徴とエネルギー特性と安定性を相関させる.

主な方法:

エントルピーを測定するために室温カロメトリーを使用した.
溶解のエンタルピーは,カチオン溶解とPOM相互作用の観点から分析された.
構造の安定性は,カロリメトリックデータと合成観察から推測された.

主要な成果:

溶解のエンタルピー (ΔHdiss) は,カチオン溶解と結合部位の相互作用によって影響される.
水酸化ブリッジを持つウラニル過酸化POMは,過酸化ブリッジを持つものよりも低いΔHf,{aq}と高い安定性を示します.
球形のPOMトポロジーは,車輪のようなクラスターよりも安定しているように見えます.

結論:

結晶エネルギーにおけるPOMクラスターの支配的な役割のために,ΔHf,(aq) を ΔHf,(c) 値から正確に推定することができます.
ハイドロキシードブリッジや球状トポロジーなどの構造モチーフは,POMの安定性とエネルギーに大きく影響します.
開発されたカロリメトリー方法は,POMエネルギー景観を理解するための堅固な枠組みを提供します.

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