Heats of reaction of HMo(CO)₃C₅H₅ with CCl₄ and CBr₄ and of NaMo(CO)₃C₅H₅ with I₂ and CH₃. Solution thermochemical study of the MoX bond for X = H, Cl, Br, I and CH₃

The heats of reaction of HMo(CO)₃C₅H₅ with CX₄ (X = Cl, Br) producing XMo(CO)₃C₅H₅ have been measured by solution calorimetry and are -31.8±0.9 and -34.4±2.0 kcal/mole, respectively. The heats of reaction of NaMo(CO)₃C₅H₅ with I₂ and CH₃I producing IMo(CO)₃C₅H₅ and H₃CMo(CO)₃C₅H₅ are -32.3± 1.3 and -7.7± 0.3 kcal/mole. Oxidation with Br₂CCl₄ yielding Br₃Mo(CO)₂C₅H₅ was measured for the following complexes: (C₅H₅(CO)₃Mo)₂, (-92.0±1.0 kcal/mole), BrMo(CO)₃C₅H₅ (-24.9± 2.0 kcal/mole) and HMo(CO)₃C₅H₅ (-60.7± 2.0 kcal/mole). These and other data are used to calculate the Mo-X bond strength for X = H, Cl, Br, I, and CH₃. These bond strength estimates are compared to those reported for X₂Mo(C₅H₅)₂. Iodination of H₃CMo(CO)₃C₅H₅, reported in the literature to yield CH₃I and IMo(CO)₃C₅H₅, actually produces CH₃C(O)I and I₃Mo(CO)₂C₅H₅.