Unusual reactivity of a Cr2P2 tetrahedral complex toward superhydride;: Formation of [{CpCr(CO)2}2(μ-PH2)x(μ-H)2-x] (x=1 and 2) and [⟨{CpCr(CO)2}2(μ-PH)⟩{(CpCr)2 (μ,η1:η1:η5:η5-P5)}]

Reaction of [{CpCr(CO)(2)}(2)(mu,eta(2)-P-2)] (1) with LiBEt3H in THF at -78 degrees C affords the new phosphanido complexes [{CpCr(CO)(2)}(2)(mu-PH2)(mu-H)] (2), [{CpCr(CO)(2)}(2)(mu-PH2)(2)] (3), and [[{CpCr(CO)(2)}(2)(mu-PH)]{(CpCr)(2)(mu,eta(1):eta(1):eta(5):eta(5)-P-5)}] (4), which have been characterized by single-crystal X-ray diffraction methods. The structure of 4 reveals a triple-decker sandwich complex with a distorted cyclo-P-5 middle deck. The EPR spectrum of the paramagnetic (S' = 1/2) complex 4 (T = 130 K) is interpreted with a rhombic-symmetric spin Hamiltonian. A noticeable hyperfine interaction with two P-31 nuclei is observed.