Structural characterization of 1 : 1 adducts of silver(I) (pseudo-) halides (AgX, X = NCO, Cl, Br, I) with Ph2E(CH2)EPh2 (E= P, As) ('dp(p/a)m') and 4 : 3 adducts of copper(I) halide (CuX, X = Cl, Br, I), containing trinuclear cations, of the form [X2Ag3(dppm)(3)]X and [X2Cu3(dppm)(3)](CuX2) and the novel neutral [(OCN)(3)Ag-3(dpam)(3)]