Enantiopure terdentate N-donor ligands and their Fe(II) and Co(II) complexes

Suhr, Dominique; Lötscher, Didier; Stœckli-Evans, Helen; Zelewsky, Alex von

doi:10.1016/s0020-1693(02)01204-5

Cited by 10 publications

(5 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Considering the Fe–N bond lengths (see Table ), the two N atoms corresponding to the pyridyl rings (N4 and N5) are in a range similar to those for complexes 1 and 2 . The remaining Fe–N bond (Fe1N1), which represents the interaction between iron and the nitrogen on the TTA ring, is slightly larger in comparison to those in complexes 1 and 2 , while still remaining in good agreement to other previously reported iron complexes with terpy-like ligands. − The Fe–F bond lengths fall in the range of 1.80–1.91 Å. This, coupled with the coordination environment and oxidation of the TTA ring leading to an anionic ligand, suggests the presence of Fe III metal ions. , …”

Section: Resultssupporting

confidence: 81%

Halide Influence on Molecular and Supramolecular Arrangements of Iron Complexes with a 3,5-Bis(2-Pyridyl)-1,2,4,6-Thiatriazine Ligand

et al. 2016

View full text Add to dashboard Cite

A series of iron centered complexes, namely, [Fe(Py2TTA)Cl2] (1), [Fe(Py2TTA)Br2] (2), and [Fe(μ-F)(Py2TTAO)F]∞ (3), were isolated via complexation of 3,5-bis(2-pyridyl)-1,2,4,6-thiatriazine (Py2TTAH) with various ferric halides (e.g., FeF3, FeCl3, and FeBr3). Comparison of the optical and electrochemical spectroscopy, structural analysis, and magnetic studies reveal numerous similarities between the chlorido (1) and bromido (2) derivatives, which crystallize as discrete five-coordinate iron centered complexes with coordination geometries that are intermediate between trigonal bipyramidal and square base pyramid. Conversely, the fluorido derivative (3) results in a completely different structure due to oxidation of the ligand and the formation of a one-dimensional coordination polymer held together through a bridging fluoride ion. Consequently, the spectroscopic and magnetic behavior of 3 differs significantly compared with 1 and 2. Complexes 1 and 2 exhibit paramagnetic properties typical for a mononuclear S = 5/2 system with weak intermolecular antiferromagnetic interactions at low temperatures, whereas complex 3 demonstrates significant exchange couplings within the chain and weak antiferromagnetic interchain interactions, which stabilize a canted antiferromagnetic state below 4.2 K.

show abstract

Section: Resultssupporting

confidence: 81%

Halide Influence on Molecular and Supramolecular Arrangements of Iron Complexes with a 3,5-Bis(2-Pyridyl)-1,2,4,6-Thiatriazine Ligand

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Analogous to the case for complex 13, we could under no conditions obtain high-molecular-weight polymers with catalyst 16; only oligomers with a molecular weight of 300-600 were produced. A slight cocatalyst/catalyst dependency was recognized for the produced polymers, as was true for all [bis-(iminoethyl)pyridine]iron(II) complexes (12)(13)(14). The temperature dependence of the produced polymers is much less significant than for all previously discussed complexes (Figure 9).…”

Section: Resultsmentioning

confidence: 94%

“…The square-pyramidal structure of 18 is reminiscent of certain five-coordinate iron(II) and cobalt(II) NNN derivatives reported by several research groups. 10,12,21,24 For complex 18 the basal plane consists of the two nitrogens and the oxygen atoms from the ligand and one equatorial chloride, with the remaining chloride (C11) occupying the apical position. In this geometry, the iron atom is raised 0.64 Å above the basal plane.…”

Section: Resultsmentioning

confidence: 99%

“…These catalysts showed the important role of the synergy between stereo and electronic effects of the ligands and the catalytic activity of the metal center. Since the discovery in 1998 by Brookhart 7,8 and Gibson 9,10 that complexes of late transition metals, such as iron and cobalt, with bulky 2,6-bis(imino)pyridine ligands 11,12 (NNN ligands) and their derivatives 13 were highly catalytically active for polyolefination, 14 the interest in polymerization catalysts other than metallocenes has greatly increased. [15][16][17][18][19][20][21][22][23][24][25][26][27] Because of their lower oxophilicity, 28 these "post-metallocene catalysts" are well-suited for applications in the copolymerization of R-olefins with polar monomers such as alkyl acry- lates.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Iminopyridine Complexes of 3d Metals for Ethylene Polymerization: Comparative Structural Studies and Ligand Size Controlled Chain Termination

et al. 2007

View full text Add to dashboard Cite

A variety of iron complexes bearing tridentate pyridine based ligands are presented as highly active precatalysts for the oligomerization and polymerization of ethene and propene. The ligands comprise two classes: the first class, where both ketone groups of the 2,6-diacetylpyridine are converted to imines to give symmetrical or unsymmetrical bis(imino)pyridines (NNN ligands; 1−4, 8, and 9), and the second class, where only one keto function of the 2,6-diacetylpyridine is substituted by an imine to give monoiminoacetylpyridines (NNO or MIAP ligands; 5−7). The NNN ligands have been reacted with FeCl2·4H2O to afford the corresponding metal complexes (12−17). These complexes have been activated by modified methylaluminoxane (MMAO) and tested in the oligomerization and polymerization reaction of ethene and propene. Depending on the steric bulk of the ortho substituents at the aryl group of the imines, tunable polymerization products are observed, with molecular weights (M w) of 102−106. Using the MIAP ligands, complexes of Co(II), Cr(II), Fe(II), Mn(II), and Ni(II) (18−24) have been prepared. The solid-state X-ray structures of the square-pyramidal {2-acetyl-6-[1-((2,6-diisopropylphenyl)imino)ethyl]pyridine}metal halide complexes 18, 21, and 22b (M = Co(II), Fe(II), Ni(II)) have been compared. Additionally, the solid-state structure of {2,6-bis[1-(1-biphenylimino)ethyl]pyridine}iron(II) chloride (15) is presented. All ligands and complexes have been characterized by spectroscopic methods, mass spectra, and elemental analysis.

show abstract

“…A tetrahedral Co II complex, UCUFAZ, containing a bidentate bipyridine ligand analogue to the ligand L but containing two pinene groups, has been characterized (Lo ¨tscher et al, 2001). Two tridentate ligands, UKITOX and UKIVAL (Suhr et al, 2002), composed of 2,2 0 :6 0 ,2 00 terpyridine containing two pinene groups annelated to the terminal pyridine rings, coordinated by a Co II cation together with two chloride anions to form a complex whose geometry is pseudo-trigonal-bipyramidal. Finally, Yeung et al (2009) used terpyridine ligands from the same family as the ones of Suhr et al and obtained similar structures (XUDHOU and XUDJEM).…”

Section: Database Surveymentioning

confidence: 99%

Crystal structure of di-μ-chlorido-bis{chlorido[(−)-5,6-pinenebipyridine]cobalt(II)} aquadichlorido[(−)-5,6-pinenebipyridine]cobalt(II)

Varisco¹,

Crochet²,

Mamula³

2022

Acta Cryst E

View full text Add to dashboard Cite

The crystal structure of [Co2Cl4(C17H18N2)2][CoCl2(C17H18N2)(H2O)] or [Co(L)Cl(μ-Cl)]2[Co(L)(Cl)2(OH2)], where L is the enantiopure bidentate ligand (−)-5,6-pinenebipyridine (C17H18N2), has been determined. Crystals suitable for X-ray structure analysis were obtained by slow evaporation of an ethanolic solution containing equimolar amounts of L and CoCl2·6H2O. The CoII cations all have a coordination number of five, and in each case the coordination polyhedron is a trigonal bipyramid. The Co—N bonds lengths range from 2.037 (7) to 2.195 (7) Å, and Co—Cl bonds lengths range from 2.284 (2) to 2.509 (2) Å. The asymmetric unit contains two discrete complexes, one dinuclear and the other mononuclear. Between the two molecules, two types of intermolecular interactions have been evidenced: π–π stackings involving the bipyridine units, and O—H...Cl hydrogen bonds between the hydrogen atoms of the aqua ligand coordinating to the mononuclear complex and the non-bridging chlorido ligand coordinating to the dinuclear molecule. These interactions lead to a two-dimensional supramolecular arrangement parallel to the ab plane.

show abstract

Enantiopure terdentate N-donor ligands and their Fe(II) and Co(II) complexes

Cited by 10 publications

References 39 publications

Halide Influence on Molecular and Supramolecular Arrangements of Iron Complexes with a 3,5-Bis(2-Pyridyl)-1,2,4,6-Thiatriazine Ligand

Halide Influence on Molecular and Supramolecular Arrangements of Iron Complexes with a 3,5-Bis(2-Pyridyl)-1,2,4,6-Thiatriazine Ligand

Iminopyridine Complexes of 3d Metals for Ethylene Polymerization: Comparative Structural Studies and Ligand Size Controlled Chain Termination

Crystal structure of di-μ-chlorido-bis{chlorido[(−)-5,6-pinenebipyridine]cobalt(II)} aquadichlorido[(−)-5,6-pinenebipyridine]cobalt(II)

Contact Info

Product

Resources

About