We present theoretical investigations of 2D raft-type heterometallic clusters MMoCp(or C 5 H 4 NMe 2 )(CO) 3 n (M = Cu, Ag, Au) with a triangular ( n = 3) or square ( n = 4) copper, silver, or gold core edge-bridged by three or four metalloligands MoCp(or C 5 H 4 NMe 2 )(CO) 3 , respectively (Cp = η 5 -C 5 H 5 ; C 5 H 4 NMe 2 = η 5 -C 5 H 4 NMe 2 ). Various molecular symmetries, C 1 , C s , C 2 , D 2 , and S 4 , were considered, and our calculations reveal an excellent agreement between the most stable computed structures and those determined experimentally by X-ray diffraction when the Cp ligand is used. In contrast, clusters incorporating the C 5 H 4 NMe 2 ligand display alternative geometries that are energetically more stable than those found experimentally, emphasising the crucial role of the 𝜋-bound ligand on cluster stability. For M = Cu, we demonstrate that square cores with elongated Cu–Cu distances can be stabilised, consistent with previously described systems. Energy decomposition analysis (EDA) at the BP86 level shows that the Cu, Ag, and Au clusters are stabilised by a strong interplay of electrostatic and orbital interactions, with markedly stronger binding in the tetranuclear systems due to cooperative metal–metal and metal–ligand effects. Frontier molecular orbital analysis was used to investigate the electronic structure and potential reactivity of these clusters. The results reveal that metal nature, NMe 2 substitution, and cluster nuclearity strongly affect the HOMO–LUMO gaps and charge-transfer behaviour. NMe 2 -substituted Cu and Au clusters with higher nuclearity display reduced HOMO–LUMO gaps and greater frontier orbital delocalisation, indicating an increased propensity for redox processes. Our theoretical study satisfactorily reproduces the experimental structures of these 2D raft-type heterometallic clusters and highlights the possibility of uncovering new potentially accessible geometries of transition-metal clusters.
Messaoudi et al. (Fri,) studied this question.