Thuéry Pierre, Atoini Youssef, Harrowfield Jack
NIMBE, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France.
ISIS, Université de Strasbourg, 8 allée Gaspard Monge, 67083 Strasbourg, France.
Inorg Chem. 2020 Mar 2;59(5):2923-2936. doi: 10.1021/acs.inorgchem.9b03273. Epub 2020 Feb 17.
2-Carboxycinnamic acid (ccnH) and the isomeric 1,2- and 1,3-phenylenedioxydiacetic acids (1,2- and 1,3-pddaH) have been used to synthesize eight uranyl ion complexes under solvo-hydrothermal conditions. In the four complexes [PPh][UO(ccn)(NO)] (), [PPh][UO(ccn)(dibf)] (), [UO(ccn)(bipy)] (), and [Ni(,-Mecyclam)][UO(ccn)(HCOO)] (), the ccn dianion retains a nearly planar geometry, which favors the formation of the centrosymmetric [UO(ccn)] dimeric unit. Additional terminal ligands, either neutral (bipy = 2,2'-bipyridine) or anionic (nitrate, dibf = 1,3-dihydro-3-oxo-1-isobenzofuranacetate, and formate, the two latter formed in situ), complete the uranyl coordination sphere, leading in all cases to discrete, dinuclear species. Sodium(I) bonding to the carboxylate/ether O site of the 1,2-pdda dianion in the two complexes [UONa(1,2-pdda)(OH)] () and [(UO)Na(1,2-pdda)(CO)] () results in this ligand being planar. Further lateral coordination to uranyl and sodium bonding to a uranyl oxo group allow formation of heterometallic diperiodic networks containing monoperiodic uranyl-only subunits. In the absence of Na cations, 1,2-pdda adopts a conformation in which one carboxylate group is tilted out of the ligand plane in [UO(1,2-pdda)Ni(cyclam)] () and diaxial carboxylato bonding to nickel(II) unites uranyl-only monoperiodic subunits into a diperiodic network. The 1,3-pdda ligand in [UO(1,3-pdda)(HO)] () is also nonplanar with one tilted carboxylate group, and the bridging bidentate nature of both carboxylate groups allows formation of a triperiodic framework in which both metal and ligand are four-coordinated nodes. While the emission spectra of complexes and display the vibronic progression considered typical of uranyl ion, those of complexes , , and show broad emission bands which in the case of complex completely replace the uranyl emission and which appear to be ligand-centered. The low energy of these broad bands can be rationalized in terms of the close association of certain ligand pairs within the structures.
2-羧基肉桂酸（ccnH）以及同分异构体1,2-和1,3-苯二氧基二乙酸（1,2-和1,3-pddaH）已用于在溶剂热条件下合成八种铀酰离子配合物。在四种配合物[PPh][UO(ccn)(NO)]（）、[PPh][UO(ccn)(dibf)]（）、[UO(ccn)(bipy)]（）和[Ni(,-Mecyclam)][UO(ccn)(HCOO)]（）中，ccn二价阴离子保持近乎平面的几何构型，这有利于形成中心对称的[UO(ccn)]二聚体单元。额外的末端配体，无论是中性的（bipy = 2,2'-联吡啶）还是阴离子的（硝酸根、dibf = 1,3-二氢-3-氧代-1-异苯并呋喃乙酸酯以及甲酸根，后两者原位形成），完善了铀酰的配位球，在所有情况下都导致形成离散的双核物种。在两种配合物[UONa(1,2-pdda)(OH)]（）和[(UO)Na(1,2-pdda)(CO)]（）中，钠离子与1,2-pdda二价阴离子的羧酸根/醚氧位点结合，使得该配体呈平面状。进一步与铀酰的横向配位以及钠离子与铀酰氧原子基团的结合，允许形成包含单周期仅铀酰亚单元的异金属双周期网络。在没有钠离子的情况下，1,2-pdda采取一种构象，其中在[UO(1,2-pdda)Ni(环胺)]（）中一个羧酸根基团倾斜出配体平面，并且与镍（II）的双轴羧酸根键合将仅铀酰的单周期亚单元结合成一个双周期网络。[UO(1,3-pdda)(HO)]（）中的1,3-pdda配体也不是平面的，有一个倾斜的羧酸根基团，并且两个羧酸根基团的桥连双齿性质允许形成一个三周期框架，其中金属和配体都是四配位节点。虽然配合物 和 的发射光谱显示出被认为是铀酰离子典型的振动进展，但配合物 、 和 的发射光谱显示出宽发射带，在配合物 的情况下，这些宽发射带完全取代了铀酰发射，并且似乎是以配体为中心的。这些宽发射带的低能量可以根据结构内某些配体对的紧密结合来解释。
