Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• et al. exploited the same scaffold to control the physical properties of materials. They incorporated planar terpyridine-alkyne Pt complexes as functional units and studied the intercalation of a Pt-complex guest in order to obtain Pt–Pt interactions in solution [23]. In the native state of 3, both

• -workers introduced a switchable system based on a terpyridine (terpy) ligand (Figure 8), which is structurally similar to the diphenylpyridine units used by Zimmerman in rigid clips, but can change their conformation upon complexation by a metal cation [32][33]. When substituted at the 6 and 6" positions

• , the terpyridine adopts an open "W"-shaped conformation due to the s-trans-conformation between two pyridines forced by the repulsion of the nitrogen lone pairs. Upon metal coordination the pyridine units rotate to allow for a tridentate binding to the metal cation, thus inducing a molecular motion to

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• involves the Rh-catalyzed alkylation of 2,2’:6’,2”-terpyridine 221 with 3,3-dimethyl-1-butene coupled in the presence of a catalytic amount of t-BuONa providing the mono- and dialkylated products

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• , since a variety of heteroleptic aggregation protocols have been developed by Schmittel [37] (for copper(I), zinc(II), cadmium(II), mercury(II) ions) and Yoshizawa/Fujita [38] (for palladium(II) ion) that involve pyridine-derived ligands. Highly innovative are the approaches for terpyridine-based

• PYridine and Phenanthroline complexes [85][86]), HETPHEN (HETeroleptic bisPHENanthroline complexes [87]) and HETTAP (HETeroleptic Terpyridine And Phenanthroline complexes [88]) interactions (Figure 12). Due to the different amount of donor atoms about the metal ion, the binding strength will decrease in

• binding (log K = 4.3) and the stronger copper(I) HETTAP linkage (log β = 9.3). Ligand 53 with its terpyridine (tpy) and two ZnPor sites was designed in the way that the tpy should connect with 76 via a HETTAP binding motif while simultaneously allowing binding of the pyridine terminus of 76 to one of both

[2 + 1] Cycloaddition reactions of fullerene C₆₀ based on diazo compounds

• Yuliya N. Biglova

Beilstein J. Org. Chem. 2021, 17, 630–670, doi:10.3762/bjoc.17.55

• Scheme 32 from 9,9-didecyl-9H-fluorene and monomethyl terephthalate chloride [152]. The authors of reference [153] presented a series of 2,2';6',2"-terpyridine (tpy)-substituted methanofullerenes and pyrrolidinofullerene dyads 184–186 linked through para-phenylene or para-phenyleneethynylphenylene units

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• revealed that a radical mechanism was involved in this transformation. Recently, the group of Qing [48] accomplished a Sandmeyer trifluoromethylation of aryldiazonium derivatives with NaSO2CF3 in the presence of TBHP (Scheme 28). The yield was improved by adding the tridentate ligand 2,2′,6′,2″-terpyridine

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• CF3 radical was stabilised by the presence of an excess amount of CuBF4(MeCN)4 and the tridentate ligand 2,2’;6’,2"-terpyridine (tpy) [76]. Notably, a change in the copper source caused the predominant trifluoromethanesulfonylation of the substrate (introduction of the SO2CF3 group, vide infra). A one

Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines

• Adrian E. Ion,
• Liliana Cristian,
• Mariana Voicescu,
• Masroor Bangesh,
• Augustin M. Madalan,
• Daniela Bala,
• Constantin Mihailciuc and
• Simona Nica

Beilstein J. Org. Chem. 2016, 12, 1812–1825, doi:10.3762/bjoc.12.171

• Abstract 4′-Azulenyl-substituted terpyridines were efficiently synthesized following the Kröhnke methodology via azulenylchalcone intermediates. These azulenyl-containing terpyridines showed fluorescent emission with a fluorescence quantum yield varying from 0.14, in the case of parent terpyridine, to 0.64

• steps, which can only be explained on the basis of the redox behavior of the azulene unit. The ability of the 4′-azulenyl 2,2′:6′,2″-terpyridine to bind poisoning metal cations was studied by UV–vis titrations using aqueous solutions of Hg(II) and Cd(II) chlorides as illustrative examples. Keywords

• : azulene; fluorescence; metal binding; synthesis; terpyridine; Introduction 2,2′:6′,2″-Terpyridine derivatives are extensively used organic ligands in the field of supramolecular chemistry and materials science [1][2][3][4]. Besides the interesting supramolecular architectures, metal–terpyridine complexes

Artificial Diels–Alderase based on the transmembrane protein FhuA

• Hassan Osseili,
• Daniel F. Sauer,
• Klaus Beckerle,
• Marcus Arlt,
• Tomoki Himiyama,
• Tino Polen,
• Akira Onoda,
• Ulrich Schwaneberg,
• Takashi Hayashi and
• Jun Okuda

Beilstein J. Org. Chem. 2016, 12, 1314–1321, doi:10.3762/bjoc.12.124

• ). Synthesis of terpyridyl ligands 8 and 9 A solution of terpyridine 5 (200 mg, 0.803 mmol, 1.00 equiv) in THF (10 mL) was treated with acid chloride 6 (165 mg, 0.884 mmol, 1.10 equiv) or 7 (177 mg, 0.884 mmol, 1.10 equiv) in THF (5 mL). Triethylamine (NEt3) (222 µL, 1.61 mmol, 2.00 equiv) was added to the

• affording the terpyridine ligand 8 (285 mg, 0.715 mmol, 89%) or 9 (280 mg, 0.699 mmol, 87%). 1H NMR (8, 400 MHz, CD2Cl2) δ 8.69 (m, 2H, aryl CH), 8.60 (dt, 3JHH = 8.0 Hz, 3JHH = 1.0 Hz, 2H, aryl CH), 8.26 (s, 2H, aryl CH), 7.86 (m, 2H, aryl CH), 7.34 (ddd, 3JHH = 7.4 Hz, 3JHH = 4.8 Hz, 3JHH = 1.1 Hz, 2H

• = 1.0 Hz, 2H, aryl CH), 6.75 (s, 2H, HC=CH), 3.71 (t, 3JHH = 6.8 Hz, 2H, CH2), 2.67 (t, 3JHH = 7.4 Hz, 2H, CH2), 2.09 (pent, 3JHH = 7.2 Hz, 2H, CH2) ppm. Synthesis of Cu(II)-terpyridine complexes 10 and 11 To a solution of terpyridine ligand 8 (200 mg, 0.500 mmol, 1.00 equiv) or 9 (207 mg, 0.500 mmol

Creating molecular macrocycles for anion recognition

• Amar H. Flood

Beilstein J. Org. Chem. 2016, 12, 611–627, doi:10.3762/bjoc.12.60

• purpose of transition-metal coordination, an area in which I received my Ph.D. training with Keith Gordon. I asked my postdoctoral co-worker at the time, Yongjun Li, to assist with testing the idea. We prepared a series of analogs to the common terpyridine ligand (Figure 4a,b). Once made, they indeed

• indicated that triazoles are sterically small. In the iron complex, we saw the ferrous ion’s preference for triazole change to a water molecule when oxidized up to the harder ferric ion. This process did not occur with the terpyridine control complex. Thus, we reasoned water could easily slip past the

• triazole nitrogens but not past the pyridine with the steric protection provided by a CH group (see the red arrows in Figure 4c for the overlay of the two ligands). The ruthenium complex showed intermolecular π stacking of ligands on neighboring complexes in the solid state; yet terpyridine analogs did not

Recent advances in metathesis-derived polymers containing transition metals in the side chain

• Ileana Dragutan,
• Valerian Dragutan,
• Bogdan C. Simionescu,
• Albert Demonceau and
• Helmut Fischer

Beilstein J. Org. Chem. 2015, 11, 2747–2762, doi:10.3762/bjoc.11.296

• norbornene monomer (27) functionalized with a water-soluble bis(terpyridine)ruthenium(II) complex, with dicyclopentadiene as a cross-linking agent (Scheme 12). In the resulted copolymer 28 each Ru complex is associated with two counteranions (chloride), which represents a novelty versus most cation-based

• )s. Lanthanide-containing polymers Recently, new polynorbornenes of type 53, functionalized with terpyridine and carbazole moieties and integrating a europium complex in the pendant chains, were described by Rozhkov et al. [67]. They were obtained by a metathesis copolymerization with Grubbs 3rd

• copolymerizing the europium complex of the terpyridine monomer 51 with the carbazole-substituted norbornene 50. In solution or in thin film these Eu-containing products exhibited important metal-centered photoluminescence recommending them for novel applications. Unveiling and rationalizing the interactions

The simple production of nonsymmetric quaterpyridines through Kröhnke pyridine synthesis

• Isabelle Sasaki,
• Jean-Claude Daran and
• Gérard Commenges

Beilstein J. Org. Chem. 2015, 11, 1781–1785, doi:10.3762/bjoc.11.193

• -2,2’:6’,2’’-terpyridine through a Kröhnke pyridine synthesis. Easy access to 6-acetyl-2,2’:6’,2’’-terpyridine starting from 2,6-diacetylpyridine and 2-acetylpyridine is described. The X-ray analysis of a chiral quaterpyridine and its Pt(II) complex is presented. Keywords: heterocycles; Kröhnke

• (2) in the presence of ammonium acetate and gave 6-acetyl-2,2’:6’,2’’-terpyridine (4). This intermediate was cited by Potts [28] but to our knowledge, was not described. During the preparation of nonsymmetric quaterpyridines, 6-acetyl-2,2’:6’,2’’-terpyridine (4) is the key intermediate. Recently

• Potvin et al. proposed a simple synthesis of 6,6”-diacetyl-4’-aryl-2,2’:6’,2”- terpyridines [29]. The 6,6”-diacetyl-4’-aryl-2,2’:6’,2”-terpyridine was obtained in a one-step synthesis from commercially available reactants in a 70% yield. Later, Solan et al. proposed a general strategy to prepare

Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II) complexes

• Amaresh Mishra,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2013, 9, 866–876, doi:10.3762/bjoc.9.100

• oligothienylene-ethynylene dendrons and their corresponding terpyridine-based ligands. Their complexation with Ru(II) led to interesting novel metallodendrimers with rich spectroscopic properties. All new compounds were fully characterized by 1H and 13C NMR, as well as MALDI–TOF mass spectra. Density functional

• ; oligothiophene; spectroscopy; terpyridine; Introduction Research concerning the design, characterization and application of organic semiconductors is carried out intensively due to the attractive prospects of their application in organic and molecular electronics [1][2][3][4][5]. In particular, thiophene-based

• ligands, 2,2':6',2"-terpyridine (tpy) has been used extensively, despite the low luminescence displayed by these complexes, due to the interesting geometry of the tpy ligand, which allows axial type arrangement of the substituents placed on the 4'-position of the coordinated tpy. Among them, ligands of

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

• based on the cationic LS [Fe(2,2”-bipyridine)3]2+ or [Fe(2,2":2',6'-terpyridine)2]2+ ions, where the critical field strength to reach the crossover condition is fulfilled by introducing sterically hindering groups adjacent to the donor atoms or by replacing the pyridine rings by five-membered

The effect of the formyl group position upon asymmetric isomeric diarylethenes bearing a naphthalene moiety

• Renjie Wang,
• Shouzhi Pu,
• Gang Liu and
• Shiqiang Cui

Beilstein J. Org. Chem. 2012, 8, 1018–1026, doi:10.3762/bjoc.8.114

• cytotoxicity [32]. Piao et al. developed a multiresponsive fluorescent molecular switch containing terpyridine. This diarylethene can serve as a detector for metal-ion transmembrane transport [33]. Singer et al. explored a novel diarylethene with a 7-deazaadenosine, which led to new research in photochromic

Syntheses and applications of furanyl-functionalised 2,2’:6’,2’’-terpyridines

• Jérôme Husson and
• Michael Knorr

Beilstein J. Org. Chem. 2012, 8, 379–389, doi:10.3762/bjoc.8.41

• , medicinal chemistry and material sciences. Keywords: chelate complexes; furan; heterocycles; oligopyridines; terpyridine; Introduction Since their discovery [1][2] in the 1930s, 2,2’:6’,2’’-terpyridines (tpy) (Figure 1) have attracted widespread attention because of their excellent complexing properties

• as N-donor ligands toward numerous main-group, transition-metal and lanthanide cations [3]. Coordination compounds LnM(tpy)m (n = 0–4; m = 1,2) ligated with terpyridine derivatives form stable assemblies due to the thermodynamic chelate effect. In the case of transition metal complexes, the σ-donor/π

• prepare the 4,4′,4′′-trisubstituted terpyridine 19 (Scheme 3), which bears two carboxylate groups at positions 4 and 4′′ and a furanyl ring on position 4′ [25]. The synthesis involves the use of ester-functionalised 2-acetylpyridine derivative 18 and furfuraldehyde (1). Since the reaction is performed in

Impact of the level of complexity in self-sorting: Fabrication of a supramolecular scalene triangle

• Kingsuk Mahata and
• Michael Schmittel

Beilstein J. Org. Chem. 2011, 7, 1555–1561, doi:10.3762/bjoc.7.183

• -coupling reactions [15]. A known procedure was followed to prepare the terpyridine–phenanthroline hybrid 7 [8]. The lengths of the ligands were chosen in such a way that they provide the geometrically different sides of a scalene triangle. Results and Discussion We tested both self-sorting algorithms as

• purification. The 1H NMR spectrum was found to be broad (Figure 3a). The broadening of the signals is partly due to the presence of a phenanthroline–Cu+–terpyridine complex. Due to the tetrahedral coordination behaviour of Cu+, one pyridine nitrogen atom of the terpyridine unit is left uncoordinated [30], and

• . The outcomes are similar to those observed with copper(I) ions. On the other hand, in the mixed-metal scenario the terpyridine prefers to connect with terminus 1 as embedded in 6, which is nicely illustrated from the self-sorting described in Scheme 1. Thus, the self-assembly process was

Synthesis and crystal structures of multifunctional tosylates as basis for star-shaped poly(2-ethyl-2-oxazoline)s

• Richard Hoogenboom,
• Martin W. M. Fijten,
• Guido Kickelbick and
• Ulrich S. Schubert

Beilstein J. Org. Chem. 2010, 6, 773–783, doi:10.3762/bjoc.6.96

• suitable for X-ray analysis as we previously also observed for a tosylate adduct of 2,2’:6’,2’’-terpyridine [20]. The obtained molecular structures and the packing diagrams for DiTos-A, DiTos-B, TetraTos and HexaTos are displayed in Figures 3–6, respectively. The crystallographic data, selected bond

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

• terpyridine derivatives in photochemistry, we focused our attention on the synthesis and studies of potentially photoswitchable terpyridine ligands. The synthesis of bisterpyridines linked by a diazogroup has been reported [7][8]. As well as the connection of terpyridines to spiropyran moieties [9] and

• , and investigations regarding their photochemistry. Results and Discussion Synthesis of anthracene functionalized terpyridines We synthesized the terpyridine-4,4″-diacid 3, starting from methyl 2-acetylisonicotinate (1) and 4-tert-butylbenzaldehyde (2), by a one-pot combination of a Kröhnke type

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

• perfluorocyclopentene based diarylethene bearing two terpyridine units is reported. Furthermore studies of the free ligand’s photochromism and investigations regarding the influence of various transition metal ions on the photochromic reaction are presented. The photochromism of the central diarylethene unit is

• strongly dependent on the transition metal present, vice versa the photochromic reaction seems to influence the MLCT transition of a binuclear Ru(II) complex. Keywords: coordination chemistry; diarylethene; photochromism; terpyridine; Introduction 2,2′:6′,2″-Terpyridines have been of great interest over

• recently used to develop electrochemical sensors [4][5]. A microreview concerning the synthesis of functionalized terpyridines has also been published since the electronic properties of the ligand are influenced by the substituents present [6]. Because of this impact of terpyridine derivatives in

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32