Mo-P bond lengths

For cw-Mo(CO)4(L)2 complexes, steric effects seem to dominate the substitution reactions. For L = PPhj, the rate of L displacement by CO is -200 times larger than that for L = PMePhj. The ground-state structures show that the P—Mo—P angle is distorted from 90 to 104.6 in the former and only to 92.5 in the latter. The distortion of the structure is relieved in the dissociative transition state. It should be noted that the Mo—P bond lengths are very similar, 2.577 A for PPhj and 2.555 A for PMePh2. 

The coupling constants in [PtCl(Bu3P)3] in conjunction with the approximate MO theory of the Fermi contact interaction leads to the conclusion that the platinum 6s orbital is involved to a greater extent with Pa than with P in the bonding molecular orbitals of the complex. This result is consistent with the available Pt—P bond length data Pt—P bonds are significantly longer when trans to R3P than when trans to Cl. 

In some compounds such as the Mo complex above, the P-P bond lengths are equivalent, but in others short and long bonds have been found in the same ring system. The Mo complex is made by quite simple methods (8.259). In the complex Cp Fe(P4)(P2)MoCp, P4 and P2 units are each separately coordinated to Fe and Mo atoms [26a],... 

The force constants of the Ni—P bond in P " nickel carbonyl complexes increase in the order MeaP < PHg < P(OMe)a < PFs. This order is different from that of the donor-acceptor character, as estimated from uco-The lengthening of the P—O bond of triphenylphosphine oxide upon complexation with uranium oxide has been estimated by i.r. spectroscopy. However, A -ray diffraction shows little difference in the P-O bond lengths (see Section 7). Some SCF-MO calculations on the donor-acceptor properties of McaPO and H3PO have been reported. 

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