A study of the vibration–rotation and fine structure energy levels of the NSe radical by laser magnetic resonance

Synthesis and properties of anionic ruthenium thionitrosyl and selenonitrosyl complexes that contain tetraanionic 2-hydroxybenzamidobenzene ligands

Although transition-metal complexes that contain thiocarbonyl (CS) and selenocarbonyl (CSe) ligands have been well studied, only three neutral or cationic selenonitrosyl (NSe) complexes have been reported, while anionic NSe complexes remain elusive. Herein, we report the first examples of anionic NSe-ligated ruthenium complexes, which were obtained from the reaction of anionic ruthenium nitrido complexes, elemental selenium, and 4-(N,N-dimethylamino)pyridine (DMAP). The structures of one of these ruthenium NSe complexes, as well as of the corresponding thionitrosyl (NS) and nitrosyl (NO) complexes, were systematically examined by X-ray diffraction analyses and theoretical calculations. In contrast to previous reportes, the NSe ligand in these complexes is a better π-acceptor than the NO and NS ligands and exhibits a stronger trans influence.

Accurate calculations on 9 Λ-S and 28 Ω states of NSe radical in the gas phase: potential energy curves, spectroscopic parameters and spin-orbit couplings

The potential energy curves (PECs) of 28 Ω states generated from 9 Λ-S states (X(2)Π, 1(4)Π, 1(6)Π, 1(2)Σ(+), 1(4)Σ(+), 1(6)Σ(+), 1(4)Σ(-), 2(4)Π and 1(4)Δ) are studied for the first time using an ab initio quantum chemical method. All the 9 Λ-S states correlate to the first two dissociation limits, N((4)Su)+Se((3)Pg) and N((4)Su)+Se((3)Dg), of NSe radical. Of these Λ-S states, the 1(6)Σ(+), 1(4)Σ(+), 1(6)Π, 2(4)Π and 1(4)Δ are found to be rather weakly bound states. The 1(2)Σ(+) is found to be unstable and has double wells. And the 1(6)Σ(+), 1(4)Σ(+), 1(4)Π and 1(6)Π are found to be the inverted ones with the SO coupling included. The PEC calculations are made by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson modification. The spin-orbit coupling is accounted for by the state interaction approach with the Breit-Pauli Hamiltonian. The convergence of the present calculations is discussed with respect to the basis set and the level of theory. Core-valence correlation corrections are included with a cc-pCVTZ basis set. Scalar relativistic corrections are calculated by the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. All the PECs are extrapolated to the complete basis set limit. The variation with internuclear separation of spin-orbit coupling constants is discussed in brief for some Λ-S states with one shallow well on each PEC. The spectroscopic parameters of 9 Λ-S and 28 Ω states are determined by fitting the first ten vibrational levels whenever available, which are calculated by solving the rovibrational Schrödinger equation with Numerov's method. The splitting energy in the X(2)Π Λ-S state is determined to be about 864.92 cm(-1), which agrees favorably with the measurements of 891.80 cm(-1). Moreover, other spectroscopic parameters of Λ-S and Ω states involved here are also in fair agreement with available measurements. It demonstrates that the spectroscopic parameters reported here can be expected to be reliable predicted ones.