Lori A. Watson

How Amidoximate Binds the Uranyl Cation

This study identifies how the amidoximate anion, AO, interacts with the uranyl cation, UO(2)(2+). Density functional theory calculations have been used to evaluate possible binding motifs in a series of [UO(2)(AO)(x)(OH(2))(y)](2-x) (x = 1-3) complexes. These motifs include monodentate binding to either the oxygen or the nitrogen atom of the oxime group, bidentate chelation involving the oxime oxygen atom and the amide nitrogen atom, and η(2) binding with the N-O bond. The theoretical results establish the η(2) motif to be the most stable form. This prediction is confirmed by single-crystal X-ray diffraction of UO(2)(2+) complexes with acetamidoxime and benzamidoxime anions.

Design Criteria for Polyazine Extractants To Separate AnIII from LnIII

Although polyazine extractants have been extensively studied as agents for partitioning trivalent actinides from lanthanides, an explanation for why certain azine compositions succeed and others fail is lacking. To address this issue, density functional theory calculations were used to evaluate fundamental properties (intrinsic binding affinity for a representative trivalent f-block metal, basicity, and hardness) for prototype azine donors pyridine, pyridazine, pyrimidine, pyrazine, 1,2,3-triazine, 1,2,4-triazine, and 1,3,5-triazine, as well as perform conformational analyses of bisazine chelates formed by directly connecting two donors together. The results provide criteria that both rationalize the behavior of known extractants, TERPY, TPTZ, hemi-BTP, BTP, BTBP, and BTPhen, and predict a new class of extractants based on pyridazine donor groups.

Role of the uranyl oxo group as a hydrogen bond acceptor.

Density functional theory calculations have been used to evaluate the geometries and energetics of interactions between a number of uranyl complexes and hydrogen bond donor groups. The results reveal that although traditional hydrogen bond donors are repelled by the oxo group in the [UO(2)(OH(2))(5)](2+) species, they are attracted to the oxo groups in [UO(2)(OH(2))(2)(NO(3))(2)](0), [UO(2)(NO(3))(3)](-), and [UO(2)Cl(4)](2-) species. Hydrogen bond strength depends on the equatorial ligation and can exceed 15 kcal mol(-1). The results also reveal the existence of directionality at the uranyl oxo acceptor, with a weak preference for linear U═O---H angles.

Double C(sp3) dehydrogenation as a route to coordinated Arduengo carbenes: experiment and computation on comparative ?-acidityElectronic supplementary information (ESI) available: crystallographic data. See http://www.rsc.org/suppdata/nj/b3/b305249d/

Reaction of [RuHClL2]2 (L=PiPr3) with the C/C unsaturated cyclic carbene:C(NMeCH)2 produces the 16-electron square-pyramidal RuHCl[CNMeCHCHNMe]L2 by a chloride bridge-splitting reaction. Double H2C(sp3) dehydrogenation of cyclic H2C(NMeCH2)2 is successful for producing the C/C saturated carbene (bound to Ru); the two hydrogens removed are found as RuHCl(H2)L2. In this case, the free carbene is unstable with respect to dimerization to the olefin. The 13C chemical shifts of the carbene carbons of these two complexes, the Ru/C distance, the N–C(carbene) distance, and a variety of reaction energies (from DFT calculations) and calculated atomic charges are generally consistent with these two carbenes, aromatic and non-aromatic, both binding similarly, and with little back donation from this electron-rich center. The 13C chemical shifts are perhaps the most sensitive parameter. Collectively, these results suggest that, if the C/C unsaturated and the C/C saturated Arduengo carbenes differ in their binding to this electron-rich metal center, the difference is at or below detection limits.

Inorganic chemistry and IONiC: an online community bringing cutting-edge research into the classroom.

This Viewpoint highlights creative ways that members of the Interactive Online Network of Inorganic Chemists (IONiC) are using journal articles from Inorganic Chemistry to engage undergraduate students in the classroom. We provide information about specific educational materials and networking features available free of charge to the inorganic community on IONiCs web home, the Virtual Inorganic Pedagogical Electronic Resource (VIPEr, www.ionicviper.org ) and describe the benefits of joining this community.

?-Donor olefin substituents alter olefin binding to CpFe(CO)2+Electronic supplementary information available: selected bond lengths and angles in CpFe(CO)2(H2C?CHNMe2)+ and CpFe(CO)2(H2C?CHOEt)+; calculated orbital occupancies and natural charges in the iron-olefin complex and the free olefin. See http://www.rsc.org/suppdata/nj/b3/b305252d/

The X-ray diffraction structures of the olefin complexes [CpFe(CO)2(H2CCHDo)]PF6 (Do = OEt and NMe2) have been determined to further evaluate the previous report that the distance from Fe to the olefin carbon substituted by Do (referred to as Cβ) is long or even nonbonding. These Fe–C distances are determined here to be long [2.402(10) A for Do = OEt] or nonbonding [2.823(11) A for Do = NMe2]. DFT optimization of the geometries of these, together with CpFe(CO)2 − n(PH3)n(H2CCHDo])+ for n = 1 and 2, show (a) agreement with experiment for n = 0, (b) a progression of Fe–Cβ distances to shorter values with increasing n for Do = OEt, (c) persistence of the Fe–Cβ distance at a nonbonding value for all n when Do = NMe2 and (d) the shortest Fe–Cβ distances for the weakest π-donor substituent, Do = F. These results are rationalized in terms of increased localization of nucleophilicity on the olefin Cα as the π-donor ability of Do strengthens. Therefore, not all olefins will show η2-binding.