Bimetallic Fe–Au Carbonyl Clusters Derived from Collman’s Reagent: Synthesis, Structure and DFT Analysis of Fe(CO)4(AuNHC)2 and [Au3Fe2(CO)8(NHC)2]−

A Comparative Experimental and Computational Study of Heterometallic Fe‐M (M = Cu, Ag, Au) Carbonyl Clusters Containing N‐Heterocyclic Carbene Ligands

“…In agreement with the results previously reported for the Au compound 15 ,, no M ··· M b.c.p. was found by carrying out AIM analyses on the DFT‐optimized structures of the Cu and Ag derivatives 11 and 13 .…”

“…11 – 13 were composed of a C 2 v ‐Fe(CO) 4 sawhorse/seesaw unit coordinated to two M(NHC) fragments in relative cis position, as previously found in the Au‐species Fe(CO) 4 {Au(NHC)} 2 (NHC = IMes, 15 ; IPr, 16 ) . All these compounds displayed short Fe‐M, Fe–CO and M– C c arbene contacts, as well as sub‐van der Waals M ··· C(O) contacts (Table ).…”

“…The scope of this work was further widened, in the case of Au, to other ligands and stoichiometric combinations of Au and Fe. Thus, the syntheses and thermal reactions of [Fe(CO) 4 {Au(NHC)}] – (NHC = IMes; IPr = C 3 N 2 H 2 (C 6 H 3 i Pr 2 ) 2 ), Fe(CO) 4 {Au(NHC)} 2 (NHC = IMes, IPr), Fe(CO) 4 {Au(IMes)}{Au(IPr)} and Fe(CO) 4 {Au(NHC)}{Au(PPh 3 )} (NHC = IMes, IPr) were systematically investigated , . As a result, the higher nuclearity clusters [Fe 2 (CO) 8 {Au(NHC)}] – (NHC = IMes, IPr), [Au 3 Fe 2 (CO) 8 (IMes) 2 ] – , [Au 3 {Fe(CO) 4 } 2 (PPh 3 ) 2 ] – and [Au 16 S{Fe(CO) 4 } 4 (IPr) 4 ] n+ were obtained …”

Synthesis of the Highly Reduced [Fe6C(CO)15]4– Carbonyl Carbide Cluster and Its Reactions with H+ and [Au(PPh3)]+

“…It is, however, to be highlighted that the bond between the iron centers most involved in the interactions with gold atoms is meaningfully weaker (bond order = 0.166). The average Au–Fe bond order is only slightly lower than the Fe–Fe one (0.273), whereas the value obtained for the Au–Au interaction is 0.167, which is higher than those found for heteropolymetallic complexes of the type Fe(CO) 4 (AuNHC) 2 and [Au 3 Fe 2 (CO) 8 (NHC) 2 ] – (NHC = N‐heterocyclic carbene) when using the same theoretical level . The analysis of the gold‐centered molecular orbitals confirms that the aurophilic interaction is exclusively attributable to correlation energy contributions.…”

Synthesis and Characterization of Heterobimetallic Carbonyl Clusters with Direct Au‐Fe and Au···Au Interactions Supported byN‐Heterocyclic Carbene and Phosphine Ligands

“…1) Iron carbonyl clusters surface‐decorated by [AuL] + fragments. This represents the largest class of heterobimetallic Au‐Fe carbonyl clusters, that comprises species such as Fe(CO) 4 (AuPPh 3 ) 2 , Fe(CO) 4 (AuNHC) 2 (NHC = IMes, IPr, IBu; IMes = C 3 N 2 H 2 (C 6 H 2 Me 3 ) 2 ; IPr = C 3 N 2 H 2 (C 6 H 3 i Pr 2 ) 2 ; IBu = C 3 N 2 H 2 (CMe 3 ) 2 ), [Fe 2 (CO) 8 (AuPPh 3 )] – , [Fe 3 (CO) 11 (AuPPh 3 )] – , [Fe 3 E(CO) 9 (AuPPh 3 )] – (E = O, S, Te),, Fe 3 E(CO) 9 (AuPPh 3 ) 2 (E = O, S),, [HFe 4 (CO) 12 (AuPPh 3 ) 3‐ n ] n– (n = 0, 1), Fe 4 C(CO) 12 (AuPEt 3 ) 2 , Fe 5 C(CO) 14 (AuPEt 3 ) 2 , [Fe 6 C(CO) 16 (AuPPh 3 )] –[13] and [Fe 6 C(CO) 15 (AuPPh 3 ) 2 ] 2– . These may be viewed as the result of the addition of [AuL] + (L = phosphine, N ‐heterocyclic carbene) fragments to the surface of an iron carbonyl cluster anion, i.e., [Fe(CO) 4 ] 2– , [Fe 3 (CO) 11 ] 2– , [Fe 2 (CO) 8 ] 2– , [Fe 3 E(CO) 9 ] 2– (E= O, S, Te), [HFe 4 (CO) 12 ] 3– , [Fe 4 C(CO) 12 ] 2– , [Fe 5 C(CO) 14 ] 2– , [Fe 6 C(CO) 16 ] 2– and [Fe 6 C(CO) 15 ] 4– .…”