Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Structural variability of 4f and 5f thiocyanate complexes and dissociation of uranium(III)‒ thiocyanate bonds with increased ionicity

Biswas, Saptarshi, Ma, Shuwen, Nuzzo, Stefano, Twamley, Brendan, Russell, Andrew T., Platts, James A. ORCID:, Hartl, František and Baker, Robert J. 2017. Structural variability of 4f and 5f thiocyanate complexes and dissociation of uranium(III)‒ thiocyanate bonds with increased ionicity. Inorganic Chemistry 56 (23) , pp. 14426-14437. 10.1021/acs.inorgchem.7b01560

[thumbnail of Manuscript 2nd revision no-markup.pdf]
PDF - Accepted Post-Print Version
Download (1MB) | Preview


A series of complexes [Et4N][Ln(NCS)4(H2O)4] (Ln = Pr, Tb, Dy, Ho, Yb) have been structurally characterized, all showing the same structure, namely a distorted square antiprismatic coordination geometry, and the Ln–O and Ln–N bond lengths following the expected lanthanide contraction. When the counterion is Cs+, a different structural motif is observed and the eight-coordinate complex Cs5[Nd(NCS)8] isolated. The thorium compounds [Me4N]4[Th(NCS)7(NO3)] and [Me4N]4[Th(NCS)6(NO3)2] have been characterized, and high coordination numbers are also observed. Finally, attempts to synthesize a U(III) thiocyanate compound has been unsuccessful; from the reaction mixture, a heterocycle formed by condensation of five MeCN solvent molecules, possibly promoted by U(III), was isolated and structurally characterized. To rationalize the inability to isolate U(III) thiocyanate compounds, thin-layer cyclic voltammetry and IR spectroelectrochemistry have been utilized to explore the cathodic behavior of [Et4N]4[U(NCS)8] and [Et4N][U(NCS)5(bipy)2] along with a related uranyl compound [Et4N]3[UO2(NCS)5]. In all examples, the reduction triggers a rapid dissociation of [NCS]− ions and decomposition. Interestingly, the oxidation chemistry of [Et4N]3[UO2(NCS)5] in the presence of bipy gives the U(IV) compound [Et4N]4[U(NCS)8], an unusual example of a ligand-based oxidation triggering a metal-based reduction. The experimental results have been augmented by a computational investigation, concluding that the U(III)–NCS bond is more ionic than the U(IV)–NCS bond.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Advanced Research Computing @ Cardiff (ARCCA)
Publisher: American Chemical Society
ISSN: 0020-1669
Date of First Compliant Deposit: 17 November 2017
Date of Acceptance: 13 November 2017
Last Modified: 06 Nov 2023 18:16

Citation Data

Cited 12 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item


Downloads per month over past year

View more statistics