Preparation and Structural Characterization of (Me₃SiNSN)₂Se, a New Synthon for Sulfur−Selenium Nitrides

Abstract

The reaction of (Me(3)SiN)(2)S with SeCl(2) (2:1 ratio) in CH(2)Cl(2) at -70 degrees C provides a route to the novel mixed selenium-sulfur-nitrogen compound (Me(3)SiNSN)(2)Se (1). Crystals of 1 are monoclinic and belong the space group P2(1)/c, with a = 7.236(1) A, b = 19.260(4) A, c = 11.436(2) A, beta = 92.05(3) degrees, V = 1592.7(5) A(3), Z = 4, and T = -155(2) degrees C. The NSNSeNSN chain in 1 consists of Se-N single bonds (1.844(3) A) and S=N double bonds (1.521(3)-1.548(3) A) with syn and anti geometry at the N=S=N units. The N-Se-N bond angle is 91.8(1) degrees. The EI mass spectrum shows a molecular ion with good agreement between the observed and calculated isotopic distributions. The (14)N NMR spectrum exhibits two resonances at -65 and -77 ppm. Both (13)C and (77)Se NMR spectra show single resonances at 0.83 and 1433 ppm, respectively. The reaction of 1 with an equimolar amount of SeCl(2) produces 1,5-Se(2)S(2)N(4) (2) in a good yield, and that of (Me(3)SiNSN)(2)S with SCl(2) affords S(4)N(4) (3), but the reactions of (Me(3)SiNSN)(2)Se with SCl(2) and (Me(3)SiNSN)(2)S with SeCl(2) result in the formation of a mixture of 2 and 3. A likely reaction pathway involves the intermediate formation of E(2)N(2) fragments (E = S, Se).

N-(Diphenylselenio)diphenylsulfimidium tetraphenylborate

“…This suggests that the true SeÐN distance in the system is actually longer than that quoted, which, intriguingly, places the bond within the range normally associated with SeÐN single bonds. By way of illustration, an SeÐN length of 1.844 (3) A Ê has been reported for (Me 3 SiNSN) 2 Se (Konu et al, 2002), while single-bond lengths of 1.827 (5) and 1.869 (2) A Ê have also been observed in OSN±Se±NSO (Haas et al, 1991) and (Me 3 Si) 2 N±Se±N(SiMe 3 ) 2 (Bjo È rgvinsson et al, 1990), respectively.…”

Formation, Structural Characterization, and Calculated NMR Chemical Shifts of Selenium‐Nitrogen Compounds from SeCl4 and ArNHLi (Ar = supermesityl, mesityl)

“…and slightly worse for cyclic systems e.g. Se 6 (N t Bu) 2 and Se 9 (N t Bu) 6 . The isotropic shielding tensors were calculated on the optimized geometries and are shown in Table 2 along with their corresponding calculated and experimental 77 Se chemical shifts.…”

“…The current approach to use geometries optimized in the gas phase represents a compromise between accuracy and computational cost. The largest calculated systems Se 9 (N t Bu) 6 and Se{N(mes*)} 2 use over 1000 basis functions which by itself makes even DFT calculations extremely time consuming. The inclusion of solvent model during geometry optimization would have been possible only by reducing the size of the basis set.…”

“…Selenium diimides have been known for over 25 years [1]. Unlike sulfur diimides that are stable compounds and find extensive use as ligands in transition metal complexes [2Ϫ4] and reagents in organic and inorganic syntheses [5,6], selenium diimides are thermally unstable [1, 7Ϫ9] and have therefore more limited applications. They are, however, efficient in situ reagents for allylic amination of olefins and 1,2-diamination of 1,3-dienes [1,10].…”

A Brave New World: The Heteroatom Chemistry of 1,3,2,4‐Benzodithiadiazines and Related Compounds

“…In some cases, Se II (-Se-N=S=N-Se- [13ab,16] and -N=S= N-Se-N=S=N- [17] ), Se IV (-N=Se=N-), [18] and Te IV (-N= Te=N-) [19] derivatives have also been prepared. Unlike monomeric -N=S=N-and -N=Se=N-compounds, their tellurium congeners are dimeric in the solid state.…”