Preparation, Properties, and Reactions of Metal‐Containing Heterocycles, XCVII – Differently Substituted Benzomolybdacrown Ethers and Their Capability of Including Alkali Metal Cations

The reaction of the diphosphanes 2a‐i with (OC) 4 Mo(nbd) under high dilution conditions affords the mononuclear benzomolybdacrown ethers cis ‐(OC) 4 Mo{1,2‐, 1,3‐, 1,4‐[PH 2 PCH 2 (CH 2 OCH 2 ) π CH 2 ] 2 C 6 H 4 ‐P, P′] ( 3a‐i ) (n = 1, 2). On the basis of the 31 P nucleus the inclusion behavior of the molydacycles 3a‐i toward the alkali metal salts LiBF 4 and NaBPh 4 was investigated with the aid of a NMR titration technique by using the program EQNMR. Only 3d shows an interaction with the alkali metal cation Na+ forming a 1:1 and 2:1 complex ( 3d /cation) while no interaction with Li+ could be detected. The molecular structures of 3a and 3d were elucidated by X‐ray structural analyses. Complexes 3a and 3d crystallize in the monoclinic space groups P2 1 /c and P2 1 /n with Z = 8 and 4, respectively.