Photochromic diarylethene ligands featuring 2-(imidazol-2-yl)pyridine coordination site and their iron(II) complexes

• Andrey G. Lvov,
• Max Mörtel,
• Anton V. Yadykov,
• Frank W. Heinemann,
• Valerii Z. Shirinian and
• Marat M. Khusniyarov

Beilstein J. Org. Chem. 2019, 15, 2428–2437, doi:10.3762/bjoc.15.235

• ligand. The bridging nature of the diarylethene in the complexes prevents photocyclization. Keywords: diarylethene; 2-(imidazol-2-yl)pyridine; iron(II) complex; photochromism; Introduction Transition metal complexes with photoactive ligands are of great interest for advanced photonic applications [1][2

Polysubstituted ferrocenes as tunable redox mediators

• Sven D. Waniek,
• Jan Klett,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2018, 14, 1004–1015, doi:10.3762/bjoc.14.86

• ferrocene carboxylic acids 1–4 (Scheme 2) [45][46][47][48][49][50][51][52]. The extremely bulky and electron-poor pentakis(methoxycarbonyl)cyclopentadienyl ligand gives a pseudo octahedral high-spin iron(II) complex 5, instead of forming a stable classical low-spin sandwich complex, precluding its

• ferrocene carboxylic acids 1 [45][46], 2 [47][48][49], 2a [50], 2b [51][52], 3, 4 [54] and pseudo octahedral high-spin iron(II) complex 5 with pentakis(methoxycarbonyl)cyclopentadienyl ligands [55][56]. Electrochemical data of esters 1–4 and sum of Hammett substituent constants σpa and σma. 1H NMR data (δ

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

• [135][136]. The possibility of investigating spin fluctuation rates was established with the classical iron(II) complex [Fe(phen)2(NCS)2], polymorph I [135][136]. In another case, fast dynamics have been revealed in the HS regime of the ST coordination polymer [Fe(NH2trz)3](NO3)2 (NH2trz = 4-amino

Anthracene functionalized terpyridines – synthesis and properties

• Falk Wehmeier and
• Jochen Mattay

Beilstein J. Org. Chem. 2010, 6, No. 54, doi:10.3762/bjoc.6.54

• (terpyridine)complexes 6a–b. Irradiation experiments were carried out with both the free ligands and an iron(II)-complex in order to investigate the photochemistry of the compounds. Keywords: anthracene; coordination chemistry; photochemistry; terpyridine; Introduction 2,2′:6′,2″-Terpyridines have been of

• cannot be distinguished from the reagents, because their molecular formulas and hence their molecular masses are identical. Irradiation of a Fe(II)-complex To see whether the presence of iron(II) influences the photochemistry of the ligands 5a and 5b, we irradiated the iron(II) complex 6b in acetonitrile

• be identified. Further irradiation experiments with the iron(II)-complex 6b showed that the coordination properties of the terpyridine are not influenced by the photochemistry of the anthryl residues. Hence, the reported anthracene functionalized terpyridines do not appear to be suitable building

A perfluorocyclopentene based diarylethene bearing two terpyridine moieties – synthesis, photochemical properties and influence of transition metal ions

• Falk Wehmeier and
• Jochen Mattay

Beilstein J. Org. Chem. 2010, 6, No. 53, doi:10.3762/bjoc.6.53

• ), Co(II), Ni(II) and Zn(II). The UV–vis-spectra of the iron(II) complex [Fe2+@10a], obtained by reaction of 10a with ferric chloride tetrahydrate, are shown in Figure 4. Apart from the expected bathochromic shift of the UV-bands of the ligand [18], an MLCT band at λ = 570 nm was observed. While the UV

• contrast to the iron(II) complex, the ditopic ligand seems to retain its photochromic properties in the cobalt(II) and nickel(II) complexes – synthesized from CoCl2 and [Ni(acac)2], respectively – although the photocyclisation takes much longer than with free 10a (about 5 minutes compared to ca. 30 seconds