PS-Bridged binuclear metal carbonyls from dimerization of coordinated thiophosphoryl groups: a theoretical study

The thiophosphoryl complexes (PS)M(CO) n (M from V to Co) and their corresponding dimers with P 2 S 2 ligands have been studied at the DLPNO-CCSD(T)/cc-pVTZ//M06L/cc-pVTZ level of theory. For the mononuclear complexes containing the highly bent 1- e donor PS group with ∠SPM angles of ∼115°, the (SP)V(CO) 6 and (SP)Co(CO) 4 complexes are energetically disfavored and (SP)Mn(CO) 5 is only slightly favored towards CO loss. The (SP)Cr(CO) 5 and (SP)Fe(CO) 4 complexes with a bent 2- e donor PS group with ∠SPM angles of ∼133° are both thermodynamically and kinetically disfavored towards dimerization. Similarly all of the (SP)M(CO) n (M from V to Co) complexes with linear 3- e donor PS ligands are energetically disfavored towards dimerization, excepting for Mn(CO) 4 (PS). The trans -influence of PS follows the sequence 3- e NO ≥ PS (linear) > CS > PS (2- e bent) CO. Theoretical studies indicate the complexes M(CO) n (PS) with bent 1- e /2- e donor PS groups to be unstable for giving the stable M(CO) n −1 (PS) with linear 3- e donor PS groups. In addition, only Mn 2 (CO) 8 (P 2 S 2 ) is energetically viable from the Mn(CO) 4 (PS).