The Chaotropically Synthesized Dimolybdenum(II,II) Compound*

A non-classic approach in the synthesis and crystal growth within electrostricted water solutions of highly charged ionic species allowed us to obtain bright monocrystals of the zwitterionic tetracarboxylate compound Mo2(O2CC6H3(NH3)2)4Cl8 16H2O (1). The title compound tetrakis-( -3,5-diaminobenzoate)octachlorodimolybdenum(II,II)—aqua(1/16) (1) crystallizes in the P21/c monoclinic space group with a = 11.0825(13) Å, b = 23.983(3) Å, c = 10.935(6) Å, = 103.04(3)°, and Z = 2. Proton jumps between aromatic NH3 and the neighbouring contacting groups H2O or Cl– of (1) increase the extent of donor (p– ) interactions from equatorial oxygen atoms to the central dimolybdenum(II,II) core. Existence of unequivalent carboxylate ligands with different binding affinity around the Mo2 dimer is indicated. The structure of the reference compound 3,5-diaminobenzoic acid—bis(hydrogen chloride)—hemihydrate 3,5-(H2N)2C6H3CO2H 2HCl 1/2H2O (2) was solved and compared with the structural data of (1). Triclinic needles of (2) crystallize in the P1 space group with a = 8.695(2) Å, b = 9.768(2) Å, c = 13.779(3) Å, = 67.43(2), = 68.69(2), = 72.66(2)° and Z = 4.