title: DFT calculations in the assignment of solid-state NMR and crystal structure elucidation of a lanthanum(iii) complex with dithiocarbamate and phenanthroline.
abstract: The molecular, crystal, and electronic structures as well as spectroscopic properties of a mononuclear heteroleptic lanthanum(iii) complex with diethyldithiocarbamate and 1,10-phenanthroline ligands (3 : 1) were studied by solid-state13C and15N cross-polarisation (CP) magic-angle-spinning (MAS) NMR, X-ray diffraction (XRD), and first principles density functional theory (DFT) calculations. A substantially different powder XRD pattern and13C and15N CP-MAS NMR spectra indicated that the title compound is not isostructural to the previously reported analogous rare earth complexes with the space group P21/n. Both13C and15N CP-MAS NMR revealed the presence of six structurally different dithiocarbamate groups in the asymmetric unit cell, implying a non-centrosymmetric packing arrangement of molecules. This was supported by single-crystal X-ray crystallography showing that the title compound crystallised in the triclinic space group P1[combining macron]. In addition, the crystal structure also revealed that one of the dithiocarbamate ligands has a conformational disorder. NMR chemical shift calculations employing the periodic gauge including projector augmented wave (GIPAW) approach supported the assignment of the experimental13C and15N NMR spectra. However, the best correspondences were obtained with the structure where the atomic positions in the X-ray unit cell were optimised at the DFT level. The roles of the scalar and spin-orbit relativistic effects on NMR shielding were investigated using the zeroth-order regular approximation (ZORA) method with the outcome that already the scalar relativistic level qualitatively reproduces the experimental chemical shifts. The electronic properties of the complex were evaluated based on the results of the natural bond orbital (NBO) and topology of the electron density analyses. Overall, we apply a multidisciplinary approach acquiring comprehensive information about the solid-state structure and the metal-ligand bonding of the heteroleptic lanthanum complex.
authors.affiliation: NMR Research Unit, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland. gowda.vasantha.k@gmail.com perttu.lantto@oulu.fi and Chemistry of Interfaces, Luleå University of Technology, SE-97187, Luleå, Sweden.
authors.forename: Vasantha
authors.identifier: http://orcid.org/0000-0001-9577-6845
authors.initials: V
authors.lastname: Gowda
authors.affiliation: Laboratory of Inorganic Chemistry, University of Oulu, P.O. Box 3000, FI-90014, Finland.
authors.forename: Risto S
authors.initials: RS
authors.lastname: Laitinen
authors.affiliation: NMR Research Unit, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland. gowda.vasantha.k@gmail.com perttu.lantto@oulu.fi.
authors.forename: Ville-Veikko
authors.initials: VV
authors.lastname: Telkki
authors.affiliation: Chemistry of Interfaces, Luleå University of Technology, SE-97187, Luleå, Sweden.
authors.forename: Anna-Carin
authors.initials: AC
authors.lastname: Larsson
authors.affiliation: Chemistry of Interfaces, Luleå University of Technology, SE-97187, Luleå, Sweden.
authors.forename: Oleg N
authors.initials: ON
authors.lastname: Antzutkin
authors.affiliation: NMR Research Unit, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland. gowda.vasantha.k@gmail.com perttu.lantto@oulu.fi.
authors.forename: Perttu
authors.identifier: http://orcid.org/0000-0003-0685-7657
authors.initials: P
authors.lastname: Lantto