Palladium(ii)-based cis,trans-1,3,5-triaminocyclohexane complexes demonstrating a variety of coordination modes and architecturesElectronic supplementary information (ESI) available: A detailed description of the coordinative flexibility of trans-tach. Fig. S1: Diagram defining interplanar angle ? and torsion angle ?. Table S1: interplanar angles ? and torsion angles ? for complexes 1?7. See http://www.rsc.org/suppdata/dt/b3/b307616d/

The reaction of cis, trans-1,3,5-triaminocyclohexane . 3HX (L . 3HX) with PdX2 (X = Br, Cl) affords a wide range of coordination complexes that represent the different coordination modes available to L. Monoligand complexes [Pd(LH) Cl-2] Cl (1) and [Pd(LH) Br-2](2)[PdBr4] (2) demonstrate the bidentate coordination of L with the two cis amino 'head' groups chelating the palladium(II) ion and the third trans amino 'tail' group being protonated. Diligand complexes [Pd(LH)(2)] X (X = (NO3)(4) 3, (SO4)(2) 4) show a 'head-to-head' coordination mode with the protonated trans amino groups adopting a conformation that positions them opposite to each other. Both sets of amino groups are engaged in coordination in a cyclic 'head-to-tail' fashion found in the hexanuclear ring clusters [{Pd(L)X}(6)]X-6 (X = Cl 5, Br 6). 5 and 6 are isostructural, both in the solid state and in solution, despite accommodating six chloro or bromo ligands into the cluster framework. A trinuclear complex [Pd{Pd(L) Cl-2}(2)Cl-2] (7) reveals 'tail-to-tail' coordination of two ligands for the centre palladium(II) ion in addition to their 'head' amino groups individually chelating other palladium(II) ions. Complexes 1 - 7 were characterised by single-crystal X-ray diffraction, elemental analysis, IR and by NMR spectroscopy ( 1 - 6).