title: Structural variety of zinc and copper complexes based on a 2,3-disubstituted 1,2,3,4-tetrahydroquinazoline ligand.
abstract: The ring-chain tautomerism of 2-(3-tosyl-1,2,3,4-tetrahydroquinazolin-2-yl)quinolin-8-ol (H(2)L(ring)) has been exploited to produce mononuclear complexes or, alternatively, dinuclear complexes, as desired, by varying the stoichiometry of the ligand. Cu(2+) and Zn(2+) stabilise the ring tautomeric form of the ligand in their mononuclear complexes M(HL(ring))(2). The structural characterisation of Zn(HL(ring))(2)·2MeOH·0.5H(2)O shows O,N-donor behaviour of the ring tautomer. The 1,2,3,4-tetrahydroquinazoline undergoes a ring-opening reaction upon formation of phenoxo-bridged dinuclear complexes M(2)(L(chain))(2) in which the chain tautomer is acting as O,N,N,N-donor. The crystal structure of Cu(2)(L(amide))(L(quinazoline))(MeOH)·2MeOH evidenced the sensitivity of H(2)L(ring) to the copper-mediated aerobic oxidation, which results in two derivatives of the ligand, a quinazoline and an amide. The quinazoline ligand is acting as monoanionic and mononucleating through its O,N,N binding site, while the amide ligand behaves as a trianionic and binucleating through its O,N,N,N and O,O binding sites in Cu(2)(L(amide))(L(quinazoline))(MeOH)·2MeOH.
authors.affiliation: Departamento de Química Inorgánica, Facultad de Química, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain. jesus.sanmartin@usc.es
authors.forename: Jesús
authors.initials: J
authors.lastname: Sanmartín-Matalobos
authors.forename: Cristina
authors.initials: C
authors.lastname: Portela-García
authors.forename: Luis
authors.initials: L
authors.lastname: Martínez-Rodríguez
authors.forename: Concepción
authors.initials: C
authors.lastname: González-Bello
authors.forename: Emilio
authors.initials: E
authors.lastname: Lence
authors.forename: Ana M
authors.initials: AM
authors.lastname: García-Deibe
authors.forename: Matilde
authors.initials: M
authors.lastname: Fondo
mesh_terms: D001665:Binding Sites; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D011799:Quinazolines / Q000737:chemistry*; D013057:Spectrum Analysis; D015032:Zinc / Q000737:chemistry*
chemical_list: D008024:Ligands; D009942:Organometallic Compounds; D011799:Quinazolines; D003300:Copper; D015032:Zinc