Organotransition‐Metal Complexes of Multidentate Ligands 3. The Unexpected Derivatives of Bis(3,5‐Dimethylpyrazol‐1‐YL)Methanetetracarbonylmolybdenlim(0) and‐Tungsten(0) Complexes

Thermolysis of (H2CPz′2)M(CO)4 (H2CPz′2 = bis(3,5‐dimethylpyrazol‐1‐yl)methane; M=Mo, W) in 1,2‐dimethoxyethane did not give the expected 16‐electron complexes, (H2CPz′2)M(CO)3, but gave dinuclear compounds, [(H2CPz′2)M(CO)3]2, probably containing two linear carbonyl bridges and no metal‐metal interactions. The dimers reacted with CH3CN to give mononuclear compounds, (H2CPz′2)M(CO)3(NCCH3), identical to the substitution products between (H2CPz′2)M(CO)4 and CH3CN.