Synthesis and luminescent properties of a novel tetranuclear copper(I) cluster containing a µ₄-sulfur moiety. X-Ray crystal structure of [Cu₄(µ-dppm)₄(µ₄-S)](PF₆)₂·2Me₂CO [dppm = bis(diphenylphosphino)methane]

A One-Hole Cu4S Cluster with N2O Reductase Activity: A Structural and Functional Model for CuZ*

“…Here, we report the synthesis and characterization of its one-electron reduction product, the 1-hole derivative ( 2 ). Along with the fully reduced clusters supported by diphosphine 12 ( 3a ) and diphosphinous amide 13 ( 3b ) ligands, this completes the catalytically relevant two-electron redox series of [Cu 4 (μ 4 -S)] model complexes for the first time (Figure 1c). Species 2 reduces N 2 O stoichiometrically, producing 1 + N 2 and completing a synthetic cycle for N 2 O reduction (Scheme 1).…”

A Cu4S model for the nitrous oxide reductase active sites supported only by nitrogen ligands

“…9–11 However, none of these complexes truly model the unusual μ 4 -S bridge of N 2 OR or provide insight into reduced catalytic intermediates. Phosphine 12,13 ligands have been used to stabilize “fully reduced” Cu 4 (μ 4 -S) and Cu 3 (μ 3 -S) clusters more structurally faithful to N 2 OR (Figure 1c), but the inability thus far of these systems to access open-shell oxidation states has precluded experimental determination of electron structure using typical methods of physical inorganic chemistry. 14 In this regard, a recent report of strained Cu 3 (μ 3 -S) clusters encapsulated within a tris(β-diketinimate) cyclophane cage was a noteworthy advance.…”

N2O Reductase Activity of a [Cu4S] Cluster in the 4CuI Redox State Modulated by Hydrogen Bond Donors and Proton Relays in the Secondary Coordination Sphere

“…Thec omplete suppression of reactivity owing to this deuteration is puzzling. One possibility is the presence of aparticularly large kinetic isotope effect during one or both O À H(D) bondforming steps.Exposing Yams[Cu 4 (m 4 -S)(m 2 -dppm) 4 ] 2+ complex (1' ') [20] to the reaction conditions did not result in any conversion (entry 9). Collectively,c onsidering the observations that replacing MeOH solvent with acetone solvent does not turn off the reaction but replacing NH groups in the ligand backbone with CH 2 groups does,i ti sl ikely that the backbone NH groups are acting as the hydrogen atom source to generate H 2 O, akin to the Lys397 residue in N 2 OR.…”

“…To better understand the sensitivity of N 2 Or eductase activity of 1 to solvent environment, we decided to examine its solvent-dependent structure.Repeated attempts at solving the solid-state structure of 1 using single crystals grown from [D 4 ]MeOH indicated the presence of hydrogen-bonded solvent molecules in the second sphere.H owever,Y ams [Cu 4 (m 4 -S)(m 2 -dppm) 4 ] 2+ complex (1' ') [20] can be viewed as amodel for the structure of 1 in the absence of any hydrogenbonding interactions.T he [Cu 4 S] core of 1' ' has local C 2v symmetry,w ith ar ectangle-based pyramidal core featuring Cu···Cu distances of 2.869(2) and 3.128(1) ,and a m 4 -S-atom with a t 4 ' parameter [27] of 0.56. Crystals of 1 obtained from MeOH solution provided as tructure with some key differences ( Figure 2b).…”

“…[17][18][19] The first [Cu 4 (m 4 -S)] cluster was reported in 1993 by Yamand coworkers using bridging dppm ligands (dppm = (Ph 2 P) 2 CH 2 ). [20] This 4Cu I complex lacks any well-defined redox chemistry or N 2 Oreactivity but, separately,has shown intriguing photochemical properties. [21] Our group recently accessed the 2Cu I :2Cu II and 3Cu I :1Cu II redox states of a[Cu 4 (m 4 -S)] cluster using the bridging formamidinate ligands [(2,4,6-Me 3 C 6 H 2 N) 2 CH] À , [22,23] but the 4Cu I state that would model the active form of Cu Z was unstable and could not be accessed synthetically.…”