Nucleophile-Induced Intramolecular Dipole 1,5-Transfer and 1,6-Cyclization:  Experimental and ab Initio Studies of Formation, Thermolysis, and Molecular and Electronic Structures of 3,6-Diphenyl-1-propanesulfenimido-1,2,4,5-tetrazine

Abstract

Reaction of dichlorobenzaldazine (2) with sodium azide followed by 1-propanethiol/Et3N furnished tetrazine ylide 1 as the main product. The structure of this unprecedented ylide was confirmed with single-crystal X-ray analysis [C17H17N5S, monoclinic P21/n a = 6.8294(4) Å, b = 13.6781(9) Å, c = 17.5898(12) Å, β = 90.666(1)°, Z = 4] and favorably compared with the results of ab initio calculations. The mechanisms of formation of the ylide and its thermal decomposition to 2,5-diphenyltetrazine (5) were investigated using ab initio methods and correlated with the experimental observations. The results suggest that formation of 1 involves intramolecular cyclization of a nitrile imine and thermolysis of 1 might generate a sulfenylnitrene. The formation of 1 is considered to be the first example of a potentially more general reaction.

First Examples of Metal–Organic Frameworks with the Novel 3,3′-(1,2,4,5-Tetrazine-3,6-diyl)dibenzoic Spacer. Luminescence and Adsorption Properties

“…Compound 1 crystallizes in the monoclinic space group P 2 1 / c ; the asymmetric unit consisting of a medium H 2 dbtz ligand that grows by symmetry generated an almost linear alignment between the aromatic rings and terminal carboxylate groups (dihedral angles 3–6°) and one crystallization dimethyl sulfoxide (DMSO) molecule (Figure ). In the H 2 dbtz unit, the bond distances and angles are very similar to those expected in comparison with the tetrazine and benzene rings . In the structure, there is only one type of hydrogen bond (SI, Figure S3), yielding a trinuclear unit formed by one central H 2 dbtz unit and two DMSO molecules.…”

The solid-state molecular structure of the S-nitroso derivative of l-cysteine ethyl ester hydrochloride

“…The C-S bond of the major occupancy rotamer is 1.734(2) Å, and this bond length is slightly shorter than that determined for orthorhombic L-cysteine (1.790(1) and 1.810(1) Å) [42], and for L-cysteine ethyl ester hydrochloride-urea (1.772(16) Å) [48]. However, the C-S bond length may be compared with the 1.739-1.873 Å range previously determined for related -C-S-(N)-containing compounds (Cambridge Structural Database, 2004 release; 27 entries), and is similar to the 1.749-1.814 Å range in compounds containing the -CH 2 -S(N) moiety [28,[49][50][51][52]. 3 We believe that the lower occupancy of the -S(1′)-N(2′)-O(3′) group (only 30%) probably compromises the accuracy of the determined metrical parameters for this minor component, hence we are hesitant to over-interpret these bond lengths and angles.…”

Generation of Oxynitrenes and Confirmation of Their Triplet Ground States

“…Although the parent oxynitrene (HON) is an important intermediate in combustion and atmospheric chemistry, , only relatively limited experimental investigations of oxynitrenes have been reported, − in contrast to the more thoroughly studied carbon- and nitrogen-substituted nitrenes. − (Limited reports of sulfur-substituted nitrenes have also appeared. − ) In fact, direct observations of oxynitrene intermediates (RON, R = H, Cl, Br, or CN) via low-temperature matrix IR spectroscopy have only recently been reported. − We encountered oxynitrene intermediates in our study of the photochemistry of O 2 -substituted diazeniumdiolates during the course of our development of novel photochemical precursors to nitric oxide (NO). − …”

“…[16][17][18][19][20] (Limited reports of sulfur-substituted nitrenes have also appeared. [21][22][23][24][25][26][27][28][29][30][31] In fact, direct observations of oxynitrene intermediates (RON, R ) H, Cl, Br, or CN) via low-temperature matrix IR spectroscopy have only recently been reported. [12][13][14][15] We encountered oxynitrene intermediates in our study of the photochemistry of O 2 -substituted diazeniumdiolates 32 during the course of our development of novel photochemical precursors to nitric oxide (NO).…”