Pintus Anna, Aragoni M Carla, Carcangiu Gianfranco, Caria Veronica, Coles Simon J, Dodd Eleanor, Giacopetti Laura, Gimeno Domingo, Lippolis Vito, Meloni Paola, Murgia Simone, Navarro Ezquerra Antonia, Podda Enrico, Urru Claudia, Arca Massimiliano
Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, S. S. 554 Bivio per Sestu, 09042 Monserrato, CA, Italy.
Consiglio Nazionale Delle Ricerche (CNR), Istituto di Scienze dell'Atmosfera e Del Clima (ISAC), UOS di Cagliari c/o Dipartimento di Fisica, Università degli Studi di Cagliari, S. S. 554 Bivio per Sestu, 09042 Monserrato, CA, Italy.
Molecules. 2023 Jul 30;28(15):5768. doi: 10.3390/molecules28155768.
Ammonium -(pyridin-2-ylmethyl)oxamate (AmPicOxam), synthesized from -methyl--(pyridin-2-ylmethyl)oxamate, was spectroscopically and structurally characterized and assayed as a novel precursor for the protection and consolidation of carbonate stone substrates. An in-depth characterization of treated and untreated biomicritic limestone and white Carrara marble samples was carried out by means of SEM microscopy, X-ray powder diffraction, helium pycnometry, determination of water transport properties, and pull-off tests. The improved solubility (1.00 M, 16.5% /) of the title compound with respect to ammonium oxalate (0.4 M, 5% /) results in the formation of a thicker protective coating of calcium oxalate (CaOx) dihydrate (weddellite) on marble and biomicrite samples after the treatment with 5% and 12% / water solutions, producing a reduction in the stone porosity and increased cohesion. Theoretical calculations were carried out at the DFT level to investigate both the electronic structure of the -(pyridin-2-ylmethyl)oxamate anion and the hydrolysis reaction leading from AmPicOxam to CaOx.
由α-甲基-α-(吡啶-2-基甲基)草氨酸合成的铵-(吡啶-2-基甲基)草氨酸酯(AmPicOxam)，通过光谱和结构表征，并作为一种用于保护和加固碳酸盐石材基质的新型前体进行了测定。借助扫描电子显微镜(SEM)、X射线粉末衍射、氦比重瓶法、水传输性能测定和拉拔试验，对处理过和未处理的生物微晶石灰岩及白色卡拉拉大理石样品进行了深入表征。与草酸铵(0.4 M, 5% /)相比，标题化合物具有更高的溶解度(1.00 M, 16.5% /)，在用5%和12% /的水溶液处理后，在大理石和生物微晶样品上形成了更厚的二水合草酸钙(CaOx)(水草酸钙石)保护涂层，使石材孔隙率降低，内聚力增加。在密度泛函理论(DFT)水平上进行了理论计算，以研究α-(吡啶-2-基甲基)草氨酸阴离子的电子结构以及从AmPicOxam到CaOx的水解反应。
