Unusual reactivity of a Cr2P2 tetrahedral complex toward superhydride; Formation of [{CpCr(CO)(2)}(2)(mu-PH2)(x)(mu-H)(2-x)] (x=1 and 2) and [<{CpCr(CO)(2)}(2)(mu-PH)>{(CpCr)(2) (mu,eta(1):eta(1):eta(5):eta(5)-P-5)}]

Reaction of [{CpCr(CO)(2)}(2)(mu,eta(2)-P-2)] (1) with LiBEt3H in THF at -7 8 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-P H)]{(CpCr)(2)(mu,eta(1):eta(1):eta(5):eta(5)-P-5)}] (4), which have been ch aracterized 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 hy perfine interaction with two P-31 nuclei is observed.