A Systematic Study on the Coordination Properties of the Guanidine Ligand Bis(tetramethylguanidino)propane with the Metals Manganese, Cobalt, Nickel, Zinc, Cadmium, Mercury, and Silver

The transition metal complexes with the ligand 1.3-bis(N,N,N`,N`-tetramethylguanidino)propane (btmgp), [Mn(btmgp)Br-2] (1), [Co(btmgp)Cl-2] (2), [Ni(btmgp)l(2)] (3), [Zn(btmgp)Cl-2] (4), [Zn(btmgp)(O2CCH3)(2)] (5), [Cd(btmgp)Cl-2] (6), [Hg(btmgp)Cl-2] (7) and [Ag-2(btmgp)(2)][CIO4](2)center dot 2MeCN (8), were prepared and characterised for the first time. The stoichiometric reaction of the corresponding water-free metal salts with the ligand btmgp in dry MeCN or THF resulted in the straightforward formation of the mononuclear complexes 1-7 and the binuclear complex 8. In complexes with M-II the metal ion shows a distorted tetrahedral coordination whereas in 8, the coordination of the M-I ion is almost linear. The coordination behavior of btmgp and resulting structural parameters of the corresponding complexes were discussed in an comparative approach together with already described complexes of btmgp and the bisguanidine ligand N-1,N-2-bis(1,3-dimethylimidazolidin-2-ylidene)-ethane-1,2-diamine (DMEG(2)e), respectively.