Transient chirality in a distal-substituted resorcinarene metal complex

Abstract

A novel distal bidentate S/S resorcinarene ligand has been synthesised and a bis-mu-chloro-bridged palladium(II) complex obtained. The solid state structure for this complex represents the first crystal structure evidence for a bispalladium-mu-chloro-bridged complex bound to thioether ligands. Furthermore, solution NMR studies revealed conformational changes in the flexible resorcinarene ligand and discreet transient chirality around the sulfur centres.

Mechanistic Study of Enantioselective Pd-Catalyzed C(sp3)–H Activation of Thioethers Involving Two Distinct Stereomodels

“…12−14 Our interest in thioethers was inspired by their extensive coordination chemistry, notably the prochiral nature of the sulfur(II) atom. 15 As the lone pairs on sulfur(II) are enantiotopic, the coordination of a prochiral thioether with a chiral transition metal catalyst may generate intermediate diastereomeric transition metal−thioether complexes, where sulfur chirality inversion may proceed via (A) substrate dissociation/re-association or (B) direct metal−bound sulfur-(II)-inversion at room temperature; 16,17 an example of metal− bound sulfur(II)-inversion by Norton is shown in Scheme 1A. 18 We thus endeavored to exploit transient sulfur-centered chirality as a means of stereochemical relay from a fixed ligand chiral center to the substrate prochiral center via the intermediacy of a chiral-sulfur center and to use this to deconvolute the role played by directing groups for enantioselective C(sp 3 )−H activation (Scheme 1B).…”

Nickel, palladium and platinum

“…32 The synthesis of S,S resorcinarene ligand (17) and its sulfur-bonded Pd(II) complex, [Pd 2 (17)(m-Cl) 2 Cl 2 ], have been reported. 33 In a tutorial review metal-based anion receptors in the context of first-and second-sphere coordination are presented. 34 The first examples of an optically active Birch reduced tertiary phosphine (18) and successful hydrophosphination to (19) have been reported.…”

“…The water-soluble probe was successfully applied in the visualizing of the site of Hg(II) accumulation as well as estimating of trace amounts of mercury ions in live cells by two-photon microscopy. 64 A series of Pt(II) complexes (33) with monoanionic tridentate isoindoline derivatives display brightorange to red, room-temperature luminescence in fluid dichloromethane solutions with microsecond to sub-microsecond ranges of emissive lifetimes. 65 A series of lepidine containing cyclometallated Pt(II) complexes [Pt(34)acac] have been synthesized.…”

A Bidentate Resorcinarene‐Based Palladium Carbene Complex

“…In our research group, we have had an interest in resorcinarenes and calixarenes as ligand platforms, and noted that the literature has only a few examples of calixarene or resorcinarene cavitand, derived NHCs. Owing to the interest in bidentate NHCs,, and our own interest in the development of more flexible bridged bidentate resorcinarene ligands, we chose to target compounds of the type 4 shown in Scheme . Our prior work involved a protracted synthetic method for synthesis of the prerequisite distally functionalized resorcinarene.…”