Synthesis and Chemical Properties of Metalladithiolene and Metalladithiazole Rings. Unique Reactions Due to Coexistence of Aromaticity and Unsaturation

Abstract

The syntheses and unique chemical properties of metalladithiolene rings (especially in [CpM(S2C2R1R2)]-type complexes) found by our research group are reviewed. The constructions of metalladithiolene rings by one-pot reaction among [CpM(CO)n], alkyne, and elemental sulfur and by the reaction between [CpM(CO)n] and sulfur-containing heterocyclic compounds are described. Several ionic and radical substitution reactions are presented. The substitutions by carbon-centered and sulfur-centered radicals occur in the metalladithiolene rings. Benzoyloxy-substitution by dibenzoyl peroxide (BPO) and succinimido-substitution by N-halosuccinimides (NXS) proceed via ionic mechanisms induced by the heterolysis of BPO and NXS in the interaction with the lone pair electrons at the sulfur atoms. These substitutions are due to the aromatic character of the metalladithiolene rings. The unique addition reactions due to the unsaturated character of the metalladithiolene rings are also described. Diazo compounds and azides react with [CpM(S2C2R1R2)]-type metalladithiolenes to form alkylidene- and imido-bridges between metal and sulfur. Quadricyclane and dimethyl acetylenedicarboxylate add between metal and sulfur. These addition products undergo a variety of types of dissociation: by heating, illumination, or electrochemical redox.

Electrochemical behavior of the Cp*(dithiolato)Co(III) complex [(η5-Cp*)Co(1,2-S2C2B10H10-S,S′)] and its derivatives: the effect of the ligand on half-sandwich cobalt(III) complexes

“…Thus, we suspect that the PEt 3 ligand is eliminated as the applied potential goes towards the negative direction and the ligand is too far from the coordination sphere to re-coordinate to the cobalt atom due to the enhanced steric interaction between the bulky Cp* and PEt 3 ligands. Such desorption of phosphine ligands is also reported for (h 5 -Cp)Co(S 2 C 2 X 2 )(L) complexes previously [7,8]. The CV of 2d (Fig.…”

“…Copies of this information may be obtained free of charge from The Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (Fax: '/44-1223-336033; email: deposit@ccdc.cam.ac.uk or www: http:// www.ccdc.cam.ac.uk). Table 3 Selected bond lengths (Å ) and bond angles (8) in 2d×/C 7 H 8…”

“…(1); see more detailed mechanism is expected as in Refs. [7,8]). Judging from the potential scan rate, the re-coordination process is completed within a few seconds.…”

Sulfur-centered and nitrogen-centered radical substitution reactions of aromatic CpCo(dithiolene) complex with 2,2′-Dibenzothiazolyl disulfide

“…Among them, p-extended metalladithiolene compounds are useful for molecular materials such as molecular conductors [3], magnetic materials [4] and optical materials [5]. On the other hand, one interesting chemical property is due to coexistence of aromaticity and unsaturation of the metallacycle [6]. Namely, they show not only electrophilic substitution reactions but also addition reactions on the ring.…”

“…Namely, they show not only electrophilic substitution reactions but also addition reactions on the ring. We have studied on the chemical reactivities of organometallic [CpM(dithiolene)] complexes (M ¼ Co, Rh, Ir) so far [6,7]. Addition reactions involve alkylidene-, imido-, alkyne-, and norbornene-addition into the MeS bond due to unsaturation of the metallacycle [8].…”