The tritopic phosphanylthiolato ligand P(2-SHC6H4)2(2,4,6-iPr3C6H2) enables formation of a thiolato-bridged dinuclear nickel(II) complex featuring a Ni2S2 butterfly core

The bulky tritopic phosphanylthiolato pincer ligand (Tipp)P(2-SHC6H4)2 (Tipp = 2,4,6-iPr3C6H2) (TippPS2H2) reacts with nickel dichloride to give the dinuclear nickel(II) complex [Ni{(Tipp)P(mu-2-SC6H4)2-kappa 3S,S',P}]2 (1). The X-ray structure analysis of 1 shows a dinuclear complex consisting of two nickel(II) phosphanyldithiolato units formed with the dianionic tridentate pincer ligand, [Ni(TippPS2)], which dimerise via thiolato bridges involving one of the two sulfur atoms of each pincer ligand. The resulting four -membered central Ni2S2 ring has a butterfly conformation. The molecule is located on a crystallographic twofold axis and displays two chiral phosphorus centres. Only the rac isomer is formed diastereoselectively; both enantiomers of 1 (R,R and S,S) are present in the unit cell.