A tert-butyl/cyano substituted (1,2,3,5-dithiadiazolyl)benzene and η2 π complexes with CpCr(CO)2

Coordination complexes of thiazyl rings — Synthesis, structure, and density functional theory (DFT) computational analysis of CpCr(CO)x(x= 2, 3) complexes of fluorinated and nonfluorinated 1λ3-1,2,4,6-thiatriazinyls with differing Cr–S bond orders

“…This bonding mode is thus very similar to what is observed in the case of the aryl 2 -DTDA complexes of type III. [33][34][35] In the latter case, we were able to show that such complexes in solution are in dynamic exchange between the exo (major) and endo (minor) isomers in solution, while, by using different remote substituents on the aryl ring, either one or the other crystallizes preferentially. However, for 6a and 6b only, the exo form has yet to be isolated and the solution behaviour seems to be dominated by a single species according to the NMR evidence.…”

“…Previous work in our laboratories has shown that the B3PW91 functional works extremely well at reproducing the metrics of thiazyl complexes of first-row transition metals. [33][34][35]73 The structure of complex 3 is unprecedented in the literature; there are no other known metal complexes derived from 2, nor are there any known complexes of CpCr(CO) 3 in which a single S atom incorporated into a ring is coordinated to Cr. Indeed, in the N,N=-dimethylthiocarbamato-S derivative IX (structure refcode XUJGOY), the metal atom is found to be rigorously in the plane of the ligand and not coordinated perpendicularly to its well-developed system.…”

“…A very distinct histogram peak is found between 2.33 and 2.37 Å for the 2 -DTDAs, that is structures of type III and IV, which are thus found to have Cr-S bond orders of 1.3, consistent with the previously assigned -bonding character of this class. [33][34][35] Fig. 3.…”

“…Previous work in our laboratories has shown that the B3PW91 functional works extremely well at reproducing the metrics of thiazyl complexes of first-row transition metal organometallics, [33][34][35]73 so this method is also adopted in this study. For consistency, all the calculations were performed with the same functional, including the ligand geometries.…”

“…[33][34][35] A signature feature of III and IV is that, in contrast to all previous complexes with low-valent metals, the S-S separation is almost unchanged from that of the dimeric radicals that have been crystallographically analyzed. Thus, oxidative addition, the dominant reaction of low-valent transition metals towards element-element bonds, is avoided for the first time for any thiazyl ring compound.…”