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A new efficient method for the synthesis of dicompartmental ligands enalH 2 8 and of tnalH2, 10 is described. This method is essentially a concise one-step route via the Mannich condensation, from 4-methyl 2-formylphenol and paraformaldehyde with appropriate amines. A series of macrocyclic heterobimetallic complexes of type [Mc(tntnam)M o](PF6)n and [Mc'(tntnim)Ni](PF 6)n where Mc = Co(III) and Zn(II), Mc ' = Co(II), Co(III) and Zn(II) and Mo = Ni(II), Cu(II) and Zn(II) have been synthesized and characterized. The macrocyclic ligands tntnim 12 and tntnam 13 contain two geometrically distinct 6-coordinate (closed-site) and 4-coordinate (open-site) compartments which are bridged by phenolic oxygens. The heterobimetallic complexes with Zn(II) or Ni(II) in the open-site are primarily formed as 5-coordinate with a chloride ion as a fifth ligand; the latter can be removed by Ag+ ion. The 1H NMR and 13C NMR of diamagnetic complexes and [Co(tntnam)ZnCl](PF6)2, 27 and [Co(tntnam)Zn](PF6)3, 28 demonstrate that the expected trans pyridine structures are formed. Solution magnetic moments of heterobimetallic complexes indicate that all Co(III) ions are spin paired, but the Ni(II) ions are spin free. The electronic absorption and emission spectra and redox couples are reported. The crystal structures of [Zn(tntnim)NiCl]PF 6C2H5OH, 16, [Zn(tntnam)Ni](PF 6)2, 22, [Zn(tntnam)Cu](PF6) 2, 23, and [Co(tnmam)Ni(H2O)](PF6) 34H2O, 25 were determined. The crystal structures demonstrate that the expected 'trans' pyridine structures are formed. Photoreactivity of heterobimetallic complexes towards molecular oxygen showed that, in spite of sensitivity of these complexes to molecular oxygens no singlet molecular oxygen, O2 (1[Delta]g), or peroxide species were generated as a result of irradiation with visible light. A series of acyclic ligands analogous to the dialdehyde ligand enalH 2, but containing different ligating groups instead of the aldehyde moieties were prepared. These include dial.
Investigations of the oxidatively-resistant hexacarboxamide cryptand, mBDCA-5t-H6, to support mono-, bi-, and trimetallic complexes are presented. Selective single metal ion insertion into the cryptand was achieved to generate the mono-Co(II) and Zn(II) complexes that contain proximal hydrogen-bonding networks enforced by the carboxamide N–H groups of the pre-organized second-coordination sphere. The cobalt(II) complex serves as a selective colorimetric turn-on fluoride sensor and represents a unique example of a transition-metal based fluoride sensor where fluoride binding takes place directly at the transition metal. The binding of fluoride is synergistic involving hydrogen-bond donors from the second-coordination sphere together with metal(II) ion coordination. Isolation of the mono-metallic Co and Zn complexes allowed for the preparation of their transition and main group metal heterobimetallic variants. Hetero- and homobimetallic complexes of cobalt(II) and zinc(II) are presented, and the reactivity of the homobimetallic complexes with O2, O−2 , and H2O2 is discussed. The cryptand was also explored as a supporting ligand for cofacially arranged divalent group 14 ions (Ge, Sn, Pb). Reaction of the di-tin(II) complex with elemental sulfur or selenium generates di-tin polychalcogenide complexes containing [mu]–E and bridging [mu]– E5 ligands (E = Se, S), where the sulfur-containing product acts reversibly as a source of S3 ∙− in DMF solution. The di-tin(II) complex also serves as a bidentate ligand for the preparation of trimetallic Sn2/M complexes (M = Ag(I), Au(I), Pd(0)). Reactivity studies of the Sn2/Pd(0) complex with substrates including CS2, S8, and 1AdC≡P are described. Terminal titanyl complexes supported by oxidatively-resistant tri- and tetrametaphosphates were prepared as molecular models of heterogeneous oxidation catalysts. These complexes react with hydrogen peroxide to produce the corresponding peroxotitanium( IV) metaphosphates, and represent rare examples of titanium oxo and peroxo systems supported by an all-oxygen ligand environment.