Reaction of [Mo(CO) 6 ] with 2 equiv. of L [L = 3-NaO 2 CC 5 H 4 N, 4-NaO 2 CC 5 H 4 N, 3,4-(NaO 2 C) 2 C 5 H 3 N, 3,5-(NaO 2 C) 2 C 5 H 3 N or 3-NaO 3 SC 5 H 4 N] in a 1 : 1 mixture of refluxing toluene and ethanol gave the water soluble bis(ligand) substituted complexes cis-[Mo(CO) 4 L 2 ] (1-5). Treatment ofcis -[W(CO) 4 (pip) 2 ] (pip = piperidine) with 2 equiv. of L [L = 3-NaO 2 CC 5 H 4 N, 4-NaO 2 CC 5 H 4 N, 3,4-(NaO 2 C) 2 C 5 H 3 N, 3,5-(NaO 2 C) 2 C 5 H 3 N or 3-NaO 3 SC 5 H 4 N] in a 1 : 1 mixture of toluene and ethanol at room temperature gave the totally water soluble complexes cis-[W(CO) 4 L 2 ] (6-10).