The reaction of K[N{P(S)Ph2}2] (R = Ph or iPr) with [Mo(N3S2)Cl3] in dichloromethane gives [Mo(N3S2){(ph2(O)PNP(S)P2}2] 1 and [Mo(N3S2){iPr2(O)PNP(S)iPr2}2] 2. X-ray crystallography revealed in both compounds the chelates are co-ordinated to octahedral metal centres. The oxygen atoms are located in the trans position to the nitrogen of the triazene ring. The absence of a chloride counter ion indicates that the metal centre has been reduced from Mo(VI) to Mo(V), and electron paramagnetic resonance spectroscopy confIrmed the reduction of the molybdenum centres. The friction reducing study of compound 1 and [Mo(N3S2)(DTBC)2]Na (DTBC = 3,5–di–tert–butylcatechol) has shown that both compounds exhibit low friction coefficient values.