Wydział Chemii

Piotr J. Chmielewski

2009

Inorganic Chemistry

48

432-445

10.1021/ic800591n

Naukowa

Angielski

Artykuł

Insertion of nickel(II), zinc, cadmium, or silver(III) into both macrocyclic crevices of 2,2′-o-xylene-bis(5,10,15,20-tetrakis(p-tolyl)-2-aza-21-carbaporphyrin) results in homometallic dimeric complexes which were isolated and characterized by NMR, UV−vis, mass spectrometry, and cyclic voltammetry. The ¹H NMR study of these systems at low temperatures (203−233 K) allowed determination of most stable conformers with respect to a rotational freedom around the xylene bridge. An unfolded conformation for the dicationic bis(silver(III)) complex was determined on the basis of 2D nuclear Overhauser effect spectrometry experimentation. A mixture of nonequally populated diastereomers is observed for bis(zinc) and bis(cadmium) complexes due to a possibility of two different orientations of the apical anionic ligands with respect to the bridge. In a reaction of 5,10,15,20-tetrakis(p-tolyl)-2-aza-21-carbaporphyrinato nickel(II) with 2-(o-bromoxylene)-5,10,15,20-tetrakis(p-tolyl)-2-aza-21-carbaporphyrin in the presence of a proton scavenger, two isomeric bis(N-confused porphyrin) complexes with one subunit “empty” and the other metalated by nickel(II) were obtained. In the product 10, the o-xylene links external nitrogens of the subunits while product 11 consists of the xylene bridge between external nitrogen of the nonmetalated subunit and internal carbon of the fragment containing a nickel(II) ion. The products were characterized by mass spectrometry, UV−vis, NMR, and, in the case of complex 11, also by X-ray crystallographic analysis (space group P1̅, a =17.007(3), b = 18.130(3), c = 18.797(2) Å, α = 105.856(13)°, β = 107.447(13)°, γ = 98.818(15)°, V = 5141.1(15) ų, Z = 2). Insertion of zinc or silver(III) into an empty crevice of 10 resulted in heterometallic zinc−nickel(II) or silver(III)−nickel(II) complexes 12 or 13, respectively, which were characterized by NMR, UV−vis, and cyclic voltammetry. The subunits in the bis(porphyrin) systems retain spectroscopic and redox properties typical for monomeric complexes.

https://doi.org/10.1021/ic800591n

https://www.acs.org/content/acs/en.html