The interactions formed in solution between the bent lanthanide metallocene Cp*Yb-2 (1) and cis-P(2)PtX(2) complexes (P-2 = a chelating phosphine; X = H, CH3) have been investigated using NMR spectroscopy. 1 has been found to form a significant interaction with the cis dihydride complexes [(Cy)(2)P(CH2),P(Cy)(2)]PtH2 (n = 2, dcype, 4; n = 3, dcypp, 6). Intermolecular exchange is slow on the NMR time scale for a 1:1 sample of 1 and 4, and there are significant perturbations in the spectral values from those of free 4. Additionally, (1)J(YbH) Of 180 HZ and J(PtYb) of 2260 Hz are present. A sample of 1 and 6 gives almost identical spectra values. Fast intermolecular exchange (NMR) occurs for samples containing an excess of the dihydride complexes but not for samples containing an excess of 1. The NMR values of a 1:1 sample of the dimethyl complex (dippe)Pt(CH3)2 (dippe = (Pr-i)(2)P(CH2)2P(Pr-i)2) (8) and 1 are perturbed from the analogous values for free 8, but fast intermolecular exchange is present on the NMR time scale down to -90 degrees C. The solid-state structure of this adduct, 9, shows a rare mode of an agostic bridging methyl interaction; however, (1)J(CH3) is unchanged from that of 8. Crystal data for 9 : monoclinic, space group C2/c, with a = 33.90(2) Angstrom, b = 11.255(6) Angstrom, c = 20.535(6) Angstrom, beta = 98.41(4)degrees, V = 7750(7) Angstrom(3), Z = 8, final R = 0.029 for 361 variables, and 3300 data with I > 3 sigma(I). A 1:1 sample of 1 and a methyl hydride complex, (dippe)Pt(CH3)-(H)(10) undergoes slow exchange in solution, with (1)J(ybH) of 168 Hz and J(PtYb) of 960 Hz. Again (I)J(CH3) is unchanged from that of free 10. The Yb-CH3 interaction likely arises from geometrical constraints, the Yb-hydride interaction holding the Yb center near the methyl group. The solid-state structure of this adduct, 11, shows an asymmetric (u-CH3)(u-H) bridge. Cystal data for 11 : monoclinic, space group P2(1)/c, with a = 18.778(5) Angstrom, b = 10.903(4) Angstrom, c = 20.255(5) Angstrom, beta = 114.74(2)degrees, V = 3766(2) Angstrom(3), Z = 4, final R = 0.069 for 327 variables, and 4694 data with I > 3 sigma(I). The NMR perturbations and coupling constants resulting from the interactions of 1 with the P(2)PtX(2) complexes are discussed in detail and correlated with the solid-state structures. The Pt-195 and Yb-171 chemical shifts of 1, the Pt(II) complexes, and the 1:1 adducts are also reported.