Journal ArticleDOI
The design of a new type of very rigid tetradentate ligand
Reads0
Chats0
TLDR
In this paper, the pendant arms of the disubstituted bispidine (3,7-diazabicyclo[3.3.1]nonane) backbone need to form six-membered chelate rings with the metal to allow a distorted tetrahedral geometry.Abstract:
Molecular mechanics calculations were used to compute the structural
properties of a new type of very rigid tetradentate ligand for tetrahedral
co-ordination geometries. The calculations indicate that the pendant arms
of the disubstituted bispidine (3,7-diazabicyclo[3.3.1]nonane) backbone
need to form six-membered chelate rings with the metal to allow a distorted
tetrahedral geometry. Smaller rings lead to five- (trigonal bipyramidal) or
six-co-ordinate (octahedral) transition-metal compounds. The quality of
these predictions is supported by the experimentally determined structure
of a cobalt(II) compound of the ligand with co-ordinated
pyridine substituents (five-membered chelate rings) and an additional
bidentate nitrate ligand. Comparison of the computed structures with the
crystal structure of the cobalt(II) compound and with that of a
ligand with methyl-protected phenyl substituents supports the rigidity of
the bispidine backbone and indicates that rotation of co-ordinating side
chains around a C–C single bond is the only flexibility in these
ligands.read more
Citations
More filters
Journal ArticleDOI
Iron coordination chemistry with tetra-, penta- and hexadentate bispidine-type ligands
Heidi Börzel,Peter Comba,Karl S. Hagen,Yaroslaw D. Lampeka,Achim Lienke,Gerald Linti,Michael Merz,Hans Pritzkow,Lyudmyla V. Tsymbal +8 more
TL;DR: In this paper, the synthesis of tetra-, penta-and hexadentate bispidine ligands with two tertiary amine and two, three or four additional donors (pyridine, phenolate or alcoholate) is described.
Journal ArticleDOI
Coordination compounds in the entatic state
TL;DR: In this article, a thorough analysis and interpretation of enhanced reactivities may in general not be assigned exclusively to steric strain, however, specific coordination geometries, enforced by the ligand sphere (protein or simple organic compounds) which may or may not be strained are often of importance.
Journal ArticleDOI
Hexadentate bispidine derivatives as versatile bifunctional chelate agents for copper(II) radioisotopes.
Stefanie Juran,Martin Walther,Holger Stephan,Ralf Bergmann,Jörg Steinbach,Werner Kraus,Franziska Emmerling,Peter Comba +7 more
TL;DR: A range of techniques, including single-crystal X-ray structure analysis, UV/vis spectroscopy, cyclic voltammetry, thin-layer- (TLC), and high-performance liquid chromatography, have been used to characterize the structure and stability of the copper(II)-bispidine complexes.
Journal ArticleDOI
Iron-catalyzed halogenation of alkanes: modeling of nonheme halogenases by experiment and DFT calculations.
Peter Comba,Steffen Wunderlich +1 more
TL;DR: The results suggest different pathways with different oxidants, and these may include iron(IV)- and iron(V)-oxo complexes as well as oxygen-based radicals.
References
More filters
Journal ArticleDOI
Ligand design for selective complexation of metal ions in aqueous solution
Journal ArticleDOI
Order of Stability of Metal Complexes
H. Irving,R. J. P. Williams +1 more
TL;DR: In this article, the stability of complexes of bivalent metal ions follows the order of the order in which they are formed, and it is shown that the stability is not correlated with the order.
Journal ArticleDOI
Host-guest complexation. 35. Spherands, the first completely preorganized ligand systems
Donald J. Cram,Takahiro Kaneda,Roger C. Helgeson,S. Bruce Brown,Carolyn B. Knobler,Emily F. Maverick,Kenneth N. Trueblood +6 more
TL;DR: In this article, a qualitative survey of the binding properties of the 18-membered-ring ligand system is presented, which is composed mainly of four to six aryloxy units attached to one another in such a way that the orbitals of the unshared electron pairs of their oxygens line an enforced cavity.
Journal ArticleDOI
Molecular mechanics calculations of transition-metal complexes
Paul V. Bernhardt,Peter Comba +1 more
TL;DR: In this paper, a molecular mechanics force field appropriate for the modeling of Cu(II), Ni(II) (S = 1), Co(III), Fe(III, Cr(III) and Zn(II)) complexes with amine, carboxylate, pyridine, and thia ether ligands is presented in its entirety.