Multinuclear Copper(I) and Silver(I) Amidinate Complexes: Synthesis, Luminescence, and CS₂ Insertion Reactivity

Abstract

Dinuclear Cu(I) and Ag(I) complexes, Cu2[(2,6-Me2C6H3N)2C(H)]2, 1, Ag2[(2,6-Me2C6H3N)2C(H)]2, 2, Cu2[2,6-(i)Pr2C6H3N)2C(H)]2, 3, and Ag2[(2,6-(i)Pr2C6H3N)2C(H)]2, 4, were synthesized from reactions of [Cu(NCCH3)4][PF6] with Na[(2,6-R2C6H3N)2C(H)] and AgO2CCH3 with [Et3NH][(2,6-R2C6H3N2C(H)], R = Me, (i)Pr. Carbon disulfide was observed to insert into the metal-nitrogen bonds of 1 to produce Cu4[CS2(2,6-Me2C6H3NC(H)═NC6H3Me2)]4, 5, with a Cu4S8 core, which represents a rare transformation of dinuclear to tetranuclear species. Insertion is also observed with 2 and CS2, with the product likely being polymeric, 6. With the (i)Pr-derivatives, CS2 insertion was also observed, albeit at much slower rate, with 3 and 4 producing hexanuclear clusters, M6[CS2(2,6-Me2C6H3NC(H)═NC6H3Me2)]6, M = Cu, 7; Ag, 8. Complexes 1 and 5 display green luminescence, a feature not shared by their Ag(I) analogs nor with 3. Notably, oxygen acts as a collisional quencher of the luminescence from 1 and 5 at a rate faster than most metal-based quenchometric O2 sensors. For example, we find that complex 1 can be rapidly and reversibly quenched by oxygen, presenting a nearly 6-fold drop in intensity upon switching from nitrogen to an aerated atmosphere. The results here provide a platform from which further group 11 amidinate reactivity can be explored.

Gold(I) and Silver(I) Complexes with Thioether Functionalized Silylamido Ligands

“…Similar short transannular argentophilic contacts have been observed in other dinuclear silver complexes with bridging bidentate ligands. Typical examples are amidinato complexes like [Ag 2 {( p ‐TolN) 2 CH} 2 ] (Ag ··· Ag: 270.5 pm), [Ag 2 {(DippN) 2 CH} 2 ] (Ag ··· Ag: 275.5–276.5 pm), [Ag 2 {( i PrN) 2 CPh} 2 ] (Ag ··· Ag: 266.0 pm), and related compounds . In the THT analogue of 7 a value of 281.4(1) pm was observed.…”

Di- and Trinuclear Mixed-Valence Copper Amidinate Complexes from Reduction of Iodine

“…Cu 2 [(2,6-Me 2 C 6 H 3 N) 2 C(H)] 2 , 1 , was synthesized as previously reported. 42 FTIR measurements were made on a Thermo-Nicolet instrument using spectroscopic grade KBr. The UV-Vis-NIR measurements were collected with a Cary 5000 instrument.…”

Cuprophilic Interactions in and between Molecular Entities

“…For example, 4 reacted with carbon disulfide to engender the formation of the tetracopper compound Cu 4 [CS 2 (2,6‐Me 2 C 6 H 3 NC(H)NC 6 H 3 Me 2 )] 4 , resulted from the insertion of CS 2 into the Cu−N bonds of 4 . Interestingly, the same reaction between CS 2 and 9 , containing two bulkier amidinates, produced the hexanuclear copper cluster Cu 6 [CS 2 (2,6‐ i Pr 2 C 6 H 3 NC(H)NC 6 H 3 Me 2 )] 6 . In addition, the alkyl derivatives of the dicopper bis‐amidinate complexes [Cu(μ‐κ 2 ‐RC(NR′) 2 )] 2 (R and R′ are aliphatic substituents) have been shown as promising precursors for atomic layer deposition (ALD) due to their low melting point, low deposition temperature, and their ability to afford pure copper films .…”