Relativistic density functional theory (DFT) calculations of the geometries and Au-P bonding of W@Au(12)PX(3) (X = H, F, Cl, Br, I, Me, OMe) and [M@Au(12)](q)PH(3) (M(q) = Hf(2-), Ta(-), W, Re(+), Os(2+), Ir(3+), Pt(4+), Au(5+)) have been carried out. There are some regular changes in geometry and binding of these two kinds of complexes with the variation of the phosphanes PX(3) and transition metals M(q). The energy decomposition analysis confirms that the PX(3) ligands are sigma donors. The donor tendency (DeltaE(sigma)/DeltaE(pi)) decreases for different X with increasing electronegativity and for different M(q) from Au(5+) to Hf(2-), while the pi-back-donation increases in the same direction. The calculated P-H bond lengths show a regular decrease from Hf(2-) to Ir(3+), but have abnormal trends for Pt(4+) and Au(5+).