PREPARATION, PROPERTIES, AND REACTIONS OF METAL-CONTAINING HETEROCYCLES .97. DIFFERENTLY SUBSTITUTED BENZOMOLYBDACROWN ETHERS AND THEIR CAPABILITY OF INCLUDING ALKALI-METAL CATIONS

The reaction of the diphosphanes 2a-f with (OC)(4)Mo(nbd) under high d ilution conditions affords the mononuclear benzomolybdacrown ethers ci s-(OC)(4)Mo{1,2-, 1,3-, 1,4-[Ph2PCH2(CH2OCH2)(n)CH2](2)C6H4-P,P'} (3a- f) (n = 1, 2). On the basis of the P-31 nucleus the inclusion behavior of the molybdacycles 3a-f toward the alkali metal salts LiBF4 and NaB Ph4 was investigated with the aid of a NMR titration technique by usin g the program EQNMR. Only 3d shows an interaction with the alkali meta l cation Na+ forming a 1:1 and 2:1 complex (3d/cation) while no intera ction with Li+ could be detected. The molecular structures of 3a and 3 d were elucidated by X-ray structural analyses. Complexes 3a and 3d cr ystallize in the monoclinic space groups P2(1)/c and P2(1)/n with Z = 8 and 4, respectively.