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Tellurocyanate, [TeCN]⁻, is the heaviest group 16 congener of the cyanate anion, [OCN]⁻. Due to the relative instability of the C─Te bond, tellurocyanate chemistry has seen only scarce attention. Here, we present the facile synthesis and thorough characterization of [K@crypt-222][TeCN]. The anion is essentially linear with interatomic distances C─N = 1.150(6)Å and C─Te = 2.051(4)Å, thus approximating a C≡N triple bond and for C─Te a bond order between 1 and 2. Fully ¹³C and ¹⁵N labeled [Te¹³C¹⁵N]⁻ allowed for the extraction of chemical shifts and all possible coupling constants (¹³C = 77.8 ppm, ¹⁵N = 285.7 ppm, ¹²⁵Te = −566more » ppm, ¹J_13C-15N = 8 Hz, ¹J_13C-125Te = 748 Hz, ²J1_5N-125Te = 55 Hz), which were also determined independently by quantum chemical calculations. In the series [ChCN]⁻ (Ch = O─Te), [TeCN]⁻ shows the strongest spin-orbit coupling (SOC) induced heavy-atom effect on the light-atom shielding (SO-HALA-effect). In contrast, ¹⁵N shifts are also well described without considering relativistic effects and/or SOC. Negative-ion photoelectron spectroscopy was used to extract the electron affinity (EA = 3.034 eV) and spin-orbit splitting (3807 cm⁻¹) of [TeCN]^•. These values continue the trends of falling EA and rising SOC in the series [ChCN]^•.« less

Abstract The newly synthesized phosphorus‐ and arsenic‐containing analogues of the thio‐ and seleno‐cyanate anions, PCSe ⁻ , AsCS ⁻ , and AsCSe ⁻ , as well as the known ion NCSe ⁻ were investigated in the gas phase by negative‐ion photoelectron spectroscopy (NIPES), velocity‐map imaging (VMI) spectroscopy, and quantum‐chemical computations. The electron affinities (EA), spin–orbit (SO) splittings, and “symmetric”/“asymmetric” stretching frequencies of the neutral radicals ECX ^. (E=N, P, As; X=S, Se), generated by electron detachment from the corresponding anions, were obtained from the spectra. The calculated EAs, SO splittings, and vibrational frequencies are in excellent agreement with the experimentalmore » measurements. These newly obtained values, when combined with those previously determined for the lighter analogues, show interesting trends on descending the pnictogen and chalcogen series. These trends are rationalized based on electronegativity arguments, the electron distributions in the HOMOs, and NBO/NRT analyses.« less

Abstract The newly synthesized phosphorus‐ and arsenic‐containing analogues of the thio‐ and seleno‐cyanate anions, PCSe ⁻ , AsCS ⁻ , and AsCSe ⁻ , as well as the known ion NCSe ⁻ were investigated in the gas phase by negative‐ion photoelectron spectroscopy (NIPES), velocity‐map imaging (VMI) spectroscopy, and quantum‐chemical computations. The electron affinities (EA), spin–orbit (SO) splittings, and “symmetric”/“asymmetric” stretching frequencies of the neutral radicals ECX ^. (E=N, P, As; X=S, Se), generated by electron detachment from the corresponding anions, were obtained from the spectra. The calculated EAs, SO splittings, and vibrational frequencies are in excellent agreement with the experimentalmore » measurements. These newly obtained values, when combined with those previously determined for the lighter analogues, show interesting trends on descending the pnictogen and chalcogen series. These trends are rationalized based on electronegativity arguments, the electron distributions in the HOMOs, and NBO/NRT analyses.« less