Syn–anti conformational switching: Synthesis and X-ray structures of tweezer and anti form in a zinc porphyrin dimer induced by axial ligands

Synthesis, Electronic Spectroscopy, Cyclic Voltammetry, Photophysics, Electrical Properties and X‐ray Molecular Structures of meso‐{Tetrakis[4‐(benzoyloxy)phenyl]porphyrinato}zinc(II) Complexes with Aza Ligands

“…Bidentate neutral N‐donor ligands (aza ligands) such as 1,4‐diazabicyclo[2.2.2]octane (dabco), 4,4‐bpyridine (4,4′‐bpy), 4‐cyanopyridine (4‐CNpy), and pyrazine (pyz) have also been used in many studies involving zinc metalloporphyrins . It is important to mention that several investigations have been performed with zinc dimers and trimers in which the porphyrins were linked together by different moieties known as spacers, and the zinc ions of these dimers or trimers (known as tweezers) are coordinated to a bidentate ligand (dabco, pyz, etc., Scheme ) . Despite the significant amount of research devoted to zinc porphyrins with bidentate aza ligands, a complete characterization of these species is not available in the literature.…”

Crystal structure of (4-cyanopyridine-κN){5,10,15,20-tetrakis[4-(benzoyloxy)phenyl]porphyrinato-κ4N}zinc–4-cyanopyridine (1/1)

“…Many structures of five-coordinate zinc porphyrins of the type [Zn(Porph)(L)] (Porph = is a porphyrinato ligand and L is a neutral unidentate ligand N-bonded to the zinc cation) are known in the literature. However, only three structures of zinc-4-NCpy non-porphyrinic species [CSD refcodes CYPYZN (Steffen & Palenik, 1977); LIMWUZ (Clegg et al, 1995) and QIDXAD (Huang et al, 2007;CCD Version 5.35 (Groom & Allen, 2014)] and one structure of a zinc-4-NCpyporphyrin derivative are reported in the literature (CSD refcode IRAFIR; Brahma et al, 2011). To gain more insight into the structural and spectroscopic properties of Zn II -Ndonor monodentate neutral ligand metalloporphyrins in general and Zn II -cyanopyridine porphyrin derivatives in particular, we report herein the synthesis, the molecular structure and the spectroscopic data of the title compound with the formula [Zn(TPBP)(4-CNpy)]Á(4-CNpy) (I).…”

Oligoporphyrins with One-and Two-Atom Covalent Bridges: Synthesis and Reactivity, Solid-State, Solution and Electronic Structures, Spectroscopy and Applications

“…Notable in this regard are the two Zn 2 molecules with a C 2 H 4 bridge. In these molecules the metal centers are connected by coordination to diamines: 117 Naturally, both are constrained to the syn stereochemistry because of the linking of the metals through the fifth coordination site. Another Zn 2 structure with a C 2 H 4 bridge 18o [GEFHIJ] also forms the syn arrangement despite no linkage of the metals.…”