Comparative Structural and Spectroscopic Analysis of Closed‐Shell Alkaline Earth (Mg, Ca) and Zn Complexes Derived from a Selenoether Framework

In the present article, we report the synthesis of magnesium, calcium, and zinc complexes derived from the selenoether ligand {Ph 2 P(S)NH–C 6 H 4 –SePh} ( 1 ). The deprotonation of ligand 1 utilizing metal silylamides M{N(SiMe 3 ) 2 } 2 (M = Mg, Ca, and Zn) conducted in tetrahydrofuran (THF) employing a 2:1 molar proportion of ligand‐to‐metal enables the synthesis of their respective complexes, namely [{ κ 2 N, S (Ph 2 P(S)N–C 6 H 4 SePh)}{ κ 3 N, S, Se (Ph 2 P(S)N–C 6 H 4 SePh)}Mg–(THF)] ( 1a ), [{Ph 2 P(S)N–C 6 H 4 SePh} 2 Ca]( 1b ), and [ κ 2 N, Se {Ph 2 P(S)N–C 6 H 4 SePh} 2 Zn] ( 1c ) in excellent yield proceeded via elimination of hexamethyldisilazane [HN(SiMe 3 ) 2 ]. Single crystal X‐ray diffraction analysis unambiguously revealed that ligand 1 exhibits three distinct coordination modes, κ ‐( N , S ), κ ‐( N , Se ), and κ‐( N , S , Se ), toward the metal centers. This coordination flexibility leads to a distorted octahedral geometry around the magnesium ion in complex 1a , whereas the zinc center in complex 1c adopts a distorted tetrahedral geometry in the solid state. In solution, the complexes were comprehensively characterized by multinuclear NMR spectroscopy ( 1 H, 13 C{ 1 H}, and 31 P{ 1 H}). Collectively, these findings expand the structural and spectroscopic understanding of closed‐shell metal complexes and highlight the versatility of the selenoether ligand in accessing structurally well‐defined coordination environments.