Effects of peripheral steric constraints and metal ion size on the structure of three five-coordinate macrocyclic ligand complexes of the type [M(C22H22N4)X], M = cobalt(III), iron(III), manganese(II); X = iodine, chlorine, triethylamine

Monochloroindium derivative of tmtaa (dibenzotetramethyltetraaza[14]annulene), [In(C22H22N4)Cl]

“…The bond distances for In--C1 [2.380 (2) A] and In-N [2.165 (5)]k average] are similar to those found in the related structure of tetraphen~,lporphyrinindium(m) chloride [2.369 (2) and 2.156 (6) A average, respectively (Ball, Lee, Marshall & Trotter, 1980)]. It has been suggested that the metal-to-axial-group bond distance becomes greater as the charge donation to the metal from the macrocyclic ligand increases (Weiss, Bursten, Peng & Goedkin, 1976). Such charge donation is expected to be significantly larger for the C22H22N42-ligand compared to the delocalized porphyrin ligand.…”

“…This displacement is signifi .c~fly greater than that found for the Ga derivative (0.48 A) (Atwood, Atwood, Cowley, Atwood & Rom/m, 1992) and may be explained in terms of the larger covalent radius of In (1.41 A) with respect to Ga (1.20 A) (Alcock, 1990). The displacement of In from the N4 plane is not unexpected, since the nitrogen-to-centre (N--Ct) distance of the dianionic tmtaa ligand lies in the range 1.85-1.87 ]k (Weiss, Bursten, Peng & Goedkin, 1976), i.e. substan, tially less than the observed In--N distance [2.165 (5) A].…”

Hydrogen Peroxide Decomposition by a Non‐Heme Iron(III) Catalase Mimic: A DFT Study

“…Calculated structures (top) and spin densities (middle) of pentacoordinate complexes 2 and experimental (hydrogen atoms omitted) [50] and calculated structures of high-spin chloride complexes 3-5 (bottom).…”

“…[49] How reliable can the computed structures of the Fe III complexes be considered? In 1976 Weiss and Goedken [50] published an X-ray structure of the high-spin (S = Figure 1, hydrogen atoms omitted), the tetramethyl-substituted derivative of ligand L2. The experimental structure is largely reproduced by the UB3LYP/6-31G* optimized structure of 6 4, as is evident from the bond lengths and the out-of-plane displacement of the ironA C H T U N G T R E N N U N G (III) ion (0.67 ).…”

Characterizations and X-ray Crystal Structure of Asymmetrical 2,4,9,11-Tetramethyl-1,5,8,12-monobenzotetraazacyclo[14]annulene Palladium(II) Complex

“…[1][2][3][4][5][6][7] The studies of the metal complexes of tetraazaannulene, which have been well known to possess chemical and thermal stability, have been of considerable attention because of their utilities as electrocatalysts or model compounds in biological system. [8][9][10][11][12][13][14] Tetraazaannulenes as ligands prefer to coordinate with a metal ion in a square-planar fashion like porphyrines or phthalocyanines.…”