Reactions of iron and ruthenium Chloride complexes with amino-substituted phosphites are described. Cp(CO)₂MCI (Cp = η⁵-C₅H₅; M = Fe, Ru) reacts with a series of P(NR₂)_n(OR)_3-n in benzene at room temperature to give [Cp(CO)₂M{P(NR₂)_n(OR)_3-n}]CI, which is converted into Cp(CO)₂M-{P(O)(NR₂)_n(OR)_2-n} by a thermal reaction. The isolation of the cationic complexes corresponding to the intermediate in the ionic mechanism of the Arbuzov-like dealkylation reaction is achieved by introduction of amino group(s) on a phosphorus atom. A comparison of spectroscopic data reveals that Ru^δ+-P^δ- polarization . is greater than Fe^δ+-P^δ+ polarization for both M-P(phosphite) and M-P(phosphonate) bonds. Reaction of [CpL₂Fe-{P(NC₄H₈)_n(OMe)_3-n}]+ with KOH gives a phosphonate complex, CpL₂Fe{P(O)(NC₄H₈)_n-1(OMe)_3-n}, with selective deamination. The mechanism proposed is that an OH^- nucleophilically attacks the phosphite phosphorus to form a metallaphosphorane complex, followed by the formation of a phosphoryl group with releasing an amino group. Electronic and steric effect on the Arbuzov-like dealkylation reaction is discussed through the reaction of Cp(CO)₂FeCI and PPh₂(OR) (R = Me, Et). Reactivity of iron phosphonate complexes is also described. Cp(CO)₂Fe{P(O)(OEt)₂} reacts with R⁺ (R⁺ = H⁺, Me⁺, CPh₃⁺) to give [Cp(CO)₂Fe-{P(OR)(OEt)₂}]+, where the Fe-P bond character changes from covalent to dative, and the formal oxidation state of the phosphorus changes from pentavalent to trivalent. In the reaction with lithium diisopropyl amide, a phosphonate group migrates from iron to the cyclopentadienyl ring.