Inter- and intra-molecular condensation patterns of (en)PdII with trans-[a2PtL2]2+ (a = am(m)ine, L = 2-aminopyridine): PtPd3 and Pt2Pd4 species with multiple amide bridges. Unexpected trapping of a pair of nitrate ions by a Pt2Pd4 double coneElectronic supplementary information (ESI) available: 1H NMR spectra of 2a, 4a and 5; views of the crystal structure of 5. See http://www.rsc.org/suppdata/dt/b3/b301708g/