Abstract
Two sulfide bridged, dppe appended trinuclear nickel(II) clusters synthesized and its weak interactions addressed computationally.
[Display omitted]
•Two Ni(II) sulfide bridged clusters synthesized using the same reagents but adopting different pathways.•These clusters were characterized by physicochemical method and single crystal X-ray.•The nature of weak interactions in both clusters have been addressed using computational techniques.•The Ni···Ni bonding have been addressed with the help of bond order calculations.
The cluster compounds are still gaining considerable attention due to their peculiar behaviour and M−M bonding or M···M interactions. In this report, two sufido-bridged, 1,2-bis-(diphenylphosphino)ethane (dppe) appended trinuclear Ni(II) clusters having formula [Ni3S2(dppe)3].2BPh4 (Ni3S2-1) and [Ni3S2(dppe)2(4-pyCH2OH)2].2PF6 (Ni3S2-2) are reported. These clusters are synthesized from the same starting reactants the xanthate ligand 4-PyCH2OCS2Na, Ni(II) and dppe employing two different reaction pathways. The obtained compounds have been characterized by microanalyses, FTIR, UV–Vis, 1H, 13C and 31P NMR spectroscopy as well as by single crystal X-ray diffraction technique. The X-ray analyses revealed that in both compounds three Ni(II) centers are coordinated to two sulfido and dppe ligands. In Ni3S2-1 three dppe and two sulfido ligands are stabilising the trinuclar cluster cation while in Ni3S2-2 along with two sulfido and two dppe ligands, two 4-pyCH2OH are also coordinating with one of the Ni(II) center. Both Ni3S2-1 and Ni3S2-2 display different non-covalent interactions along with the Ni···Ni interactions. The nature of these interactions has been addressed with the aid of Hirshfeld surface analysis, density functional theory and quantum theory of atoms-in-molecules (QTAIM) analyses. The occurrence of such non-covalent intermolecular interactions is also well supported by the non-covalent interactions reduced density gradient (NCI-RDG) approaches. Also, the Wiberg bond index, Mayer bond order and delocalization indices have been calculated to assess the nature of Ni···Ni interactions.