MIXED AMINO ACID-THIOCYANATO COMPLEXES OF DIMOLYBDENUM(II)

When solutions of Mo2(O2CCH(NH3)R)44+ and KNCS are mixed, red to red-purple crystalline compounds of composition Mo2(O2CCH(NH3)R)2(NCS)4-nH2O can be obtained. Two of these, the glycinate (R=H, n=1; 1) and the L-isoleucinate (R=CH(CH3)CH2CH3, n=4.5; 2), have been investigated in detail by X-ray crystallography. In each one the molecules have a cisoid arrangement of the amino acid groups and the four N-bonded NCS- ions together with the molybdenum atoms form a sawhorse arrangement. The Mo-Mo distances range from 2.132 (2) to 2.154 (5) Å in the four crystallographically independent molecules. The crystallographic data are as follows. For 1: space group P21/n, a=20.877 (7) Å,b=8.928 (3) Å, c=24.346 (6) Å, β=105.23 (5)°, V=4379 (2) Å3, Z=8. For 2: space group P21, a=9.034 (3) Å, b=23.807 (6) Å, c=14.489 (3) Å, β=93.75 (5)°, V=3109 (2) Å3, Z=4. © 1979, American Chemical Society. All rights reserved.