Alkali Metal, Magnesium, and Zinc Complexes of Bis(chalcogenophosphinoyl)methanide Ligands

The complexes [Na{HC(PPh 2 S) 2 }] (Na 3a ), [Na{HC(PPh 2 Se) 2 }] (Na 3b ), [K{HC(PPh 2 S) 2 }] ∞ (K 3a ), [K{HC(PPh 2 Se) 2 }] ∞ (K 3b ), [Mg{HC(PPh 2 S) 2 } 2 ] (Mg( 3a ) 2 ), [Mg{HC(PPh 2 Se) 2 } 2 ] (Mg( 3b ) 2 ), and [Zn{HC(PPh 2 S) 2 } 2 ] [Zn( 3a ) 2 ] have been prepared in good yields (69–92 %) by treatment of the neutral ligands H 2 C(PPh 2 E) 2 ( 1a , E = S; 1b , E = Se) with [Na{N(SiMe 3 ) 2 }] (Na 3a ), NaNH 2 (Na 3b ), [K{N(SiMe 3 ) 2 }] (K 3a and K 3b ), [Mg{N(SiMe 3 ) 2 } 2 ] [Mg( 3a ) 2 and Mg( 3b ) 2 ], or Me 2 Zn [Zn( 3a ) 2 ] as base in THF/toluene. These compounds were characterized in solution by multinuclear ( 1 H, 13 C, 31 P, and 77 Se) NMR spectroscopy and the X‐ray structures of K 3a , K 3b , Mg( 3a ) 2 , Mg( 3b ) 2 , and Zn( 3a ) 2 were determined. In the solid state, the E , E ′‐chelated ligands in K 3a and K 3b also engage in potassium–chalcogen interactions with adjacent molecules to form one‐dimensional ladder structures. With K 3a , both sulfur atoms of the ligand are involved in chelation leading to four‐membered K 2 S 2 rings, whereas only one selenium atom is tricoordinated in K 3b ; significant potassium ··· aryl interactions are also observed in both structures. In the homoleptic magnesium complexes Mg( 3a ) 2 and Mg( 3b ) 2 , the E,E′ chelation by the methanide ligands is supplemented by weak, unequal Mg ··· C interactions [2.781(10) and 3.199(7) Å for Mg( 3a ) 2 ; 3.331(8) and 3.217(7) Å for Mg( 3b ) 2 ]. The zinc complex Zn( 3a ) 2 is isostructural with the previously reported selenium analogue Zn( 3b ) 2 . The X‐ray structures of the S , S ′ ‐chelated complex [(TMEDA)Li 3a ] as well as new polymorphs of 1a and 1b are also reported.