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Molybdenum (VI) complexes with tridentate Schiff bases

The crystal structure analysis of the title complexes forms a part of our research on molybdenum complexes with oxygen, nitrogen and sulphur donor ligands. Molybdenum(VI) complexes with tridentate Schiff-bases have been synthesized. Crystal data: (I) MoO_2(C_1_3H_1_1O_2N)(OS(CH_3)_2), Mr = 419.30, monoclinic, a =13.573(5), b = 7.150(5), c = 16.848(5) Å , beta = 102.130(5)A, V = 1598.5(13) Å ^3, Z = 4, space group P21/n, Dcalc = 1.742 g cm^-^3, F(000) = 848, *(MoK*) = 0.975 mm-1, *(MoK*) = 0.7107 Å . (II) MoO_2(C_1_4H_1_1O_2N)(OS(CH_3)_2), Mr = 431.31, monoclinic, a = 13.521(5), b = 8.679(5), c = 15.879(5) Å , beta = 114.677(5)A, V = 1692(13) Å ^3, Z = 4, space group P21/a, Dcalc = 1.692 g cm^-^3, F(000) = 872, *(MoK*) = 0.924 mm^-^1, * (MoK*) = 0.7107 Å . (III) MoO_2(C_9H_9O_2N) (OHCH_3), Mr = 323.15, monoclinic, a = 10.3245(13), b = 9.5275(14), c = 12.88437(16) Å , beta = 110.624(10)A, V = 1182(3) Å ^3, Z = 4, space group P21/c, Dcalc = 1.815 g cm^-^3, F(000) = 648, *(MoK*) = 1.118 mm^-^1, *(MoK*) = 0.7107 Å In the crystal structures of complexes the Schiff-base ligands act in a dianionic tridentate manner giving Mo a distorted octahedral geometry. Each molybdenum atom is coordinated by two terminal oxygen atoms, one imino nitrogen, two oxygen atoms from ligand molecule (Oalk – from N-substituent ; in (I) and (III) 2-hydroxyethyl and in (II) benzyl ; and O_a_r_o- from ; in (II) and (III) salicylaldimine and in (I) 2-hydroxy-1-naphtaldimine) and by one oxygen atom from solvent molecule (Osolv ; solv = dmso or methanol). Both Mo=O distances (1.698- 1.723 Å ) and the O=Mo=O angles (105.6- 105.9^o) are in the usual range for cis-MoO_2 complexes. The imine nitrogen is trans to Mo=O with an average Mo-N distance of 2.306 Å . Mo- O_a_l_k distances are in the range 1.902-1.939 Å and Mo-Oaro distances in the range of 1.959-1.999 Å . The sixth position is occupied by a solvent molecule with the average Mo- O_s_o_l_v distance of 2.314 Å . In the structure (III) an intermolecular hydrogen bond between solvent (methanol) and terminal oxygen atom is formed: (O5)-H(51)… O(1)i [i: -x+2, y- 1/2, -z+1/2]

Tridentate Schiff bases ; Crystal structure ; Molybdenum(VI) complexes

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