Cyclopentadienylchromium Complexes of 1,2,3,5‐Dithiadiazolyls: η² π Complexes of Cyclic Sulfur–Nitrogen Compounds

Abstract

Diamagnetic π complexes are formed in the reaction between [{CpCr(CO)3}2] and dithiadiazolyl dimers [S2N2CR]2 (R=substituted phenyl rings) in which the heterocycles are η2‐coordinated to the metal in endo (depicted) or exo fashion. The isomers interconvert in solution at room temperature. These complexes are remarkable for retaining intact the SS bonds of the dithiadiazolyl radicals (C gray, H white, O red, Cr purple, S yellow, N blue, Cl green).

Metal-radical coordination complexes of thiazyl and selenazyl ligands

“…In 2006, Boeré, Goh, et al reported a new coordination motif for DTDA radicals [45]. Reaction of RDTDA (R = 4-MePh, 4-ClPh, 3-CN-5-tBuPh) with [CpCr(CO) 3 ] 2 , which readily dissociates into the 17-electron [CpCr(CO) 3 ] • radical in solution, generates η 2 π complexes in which the DTDA heterocycles remain intact.…”

“…Line drawings and crystal structures of representative examples of endo and exo coordination in the series of Cr(Cp)(CO) 2 RDTDA complexes (CSD Refcodes: SEKDOC and SEKDIW)[45].…”

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.…”

“…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.…”

“…[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.…”