Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• excellent metal-binding properties [67][122][123][124]. Accordion porphyrins and tripyrrane-crown ether hybrids The major contribution in the field of iminoporphyrinoids dates back to 1984 when Bowman-James and co-workers demonstrated a facile synthesis of the so-called accordion porphyrins (Scheme 4) [52

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

• geometrical or constitutional situation at the binding sites [92]. In a detailed recent study, the finding of a Hammett correlation in such nanorotors corroborated that a rate-determining dissociation at the rotator–metal binding interaction dictated the rotational speed [93]. Reducing Product Inhibition (RPI

Easy access to a carbohydrate-based template for stimuli-responsive surfactants

• Thomas Holmstrøm,
• Daniel Raydan and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2020, 16, 2788–2794, doi:10.3762/bjoc.16.229

• metal-binding event. This study was carried out by having pyrene fluorophores attached to the two non-chelating positions, giving rise to excimer fluorescence when the distance between them was decreased due to the ring flip [12]. Carbohydrates with gluco stereochemistry have also been used as templates

• conformation. When the 3- and 6-position are tethered, for example by metal binding, the glucopyranose ring undergoes a ring flip, bringing together the 2- and 4-position as shown in Figure 1b. Levoglucosan is the ideal starting material for such transformations as the 2- and 4-positions can be functionalized

• underlines that building block 5 is an ideal template for the synthesis of molecules with a 2,4- and 3,6-functional group pattern. However, after investigating the metal-binding properties of the synthesized diamines and the carboxylic acids, no conformational changes could be observed. Hence, the compounds

Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)–dipicolylamine complexes

• Lena Reinke,
• Julia Bartl,
• Marcus Koch and
• Stefan Kubik

Beilstein J. Org. Chem. 2020, 16, 2687–2700, doi:10.3762/bjoc.16.219

• spectra confirmed that zinc complexation had occurred under the chosen conditions. The change of the multiplicity of the methylene signal accounted for the rigidification of the DPA moiety during metal binding, which rendered the corresponding protons diastereotopic. The rate of metal exchange was

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• of the vital modes in metal binding and a range of π-conjugated planar systems having ηn-binding to metals have been reported. In contrast, buckybowls have multiple coordination sites for instance the positions available in the polycyclic architecture and also because of the presence of concave or

Molecular basis for the plasticity of aromatic prenyltransferases in hapalindole biosynthesis

• Takayoshi Awakawa and
• Ikuro Abe

Beilstein J. Org. Chem. 2019, 15, 1545–1551, doi:10.3762/bjoc.15.157

• they are a unique property of AmbP1. Remarkably, the two Mg2+- binding amino acids are located at the start or end of a β-sheet (Figure 6), which causes the corresponding β-sheet to move through the metal binding. Mg-1 is likely to maintain the overall structure of the enzyme, and Mg-2 defines the

• useful catalysts that control the regiospecificity in an environmentally friendly manner. The information from their X-ray structures will contribute to future engineering of PTases. Furthermore, the structure of AmbP1 can serve as a model to alter the reaction through creating a metal binding site

Chiral bisoxazoline ligands designed to stabilize bimetallic complexes

• Deepankar Das,
• Rudrajit Mal,
• Nisha Mittal,
• Zhengbo Zhu,
• Thomas J. Emge and
• Daniel Seidel

Beilstein J. Org. Chem. 2018, 14, 2002–2011, doi:10.3762/bjoc.14.175

• prevent the potential formation of 2:2 or other higher order complexes. Variation of the bridging moiety should allow for modulation of the distance between the metal centers. An important criterion for selecting bridging units was their known ability to engage in metal-binding, along with being readily

Metal-mediated base pairs in parallel-stranded DNA

• Jens Müller

Beilstein J. Org. Chem. 2017, 13, 2671–2681, doi:10.3762/bjoc.13.265

• –Crick base pairing was enforced to ensure the formation of parallel-stranded duplexes. Formal replacement of one C–H group in pyrrolocytosine by a nitrogen atom leads to imidazolocytosine. A series of substituted imidazolocytosine (XIC) nucleobases were investigated with respect to their metal-binding

Synthesis and metal binding properties of N-alkylcarboxyspiropyrans

• Alexis Perry and
• Christina J. Kousseff

Beilstein J. Org. Chem. 2017, 13, 1542–1550, doi:10.3762/bjoc.13.154

• for binding divalent metal cations and a modest increase in M2+ binding affinity correlated with increased alkycarboxylate tether length. Keywords: carboxylate ligand; merocyanine; metal binding; photochromism; spiropyran; Introduction Spiropyrans are a class of spiro-fused indolochromene (e.g

• butanoate-tagged spiropyran C4SP and demonstrated its high affinity for Zn2+ and Cu2+ through the involvement of the N-alkylcarboxylate in metal binding [3] (Scheme 1). Given the evident importance and widespread application of N-alkylcarboxyspiropyrans as building blocks in the synthesis of photoactive

• materials – and as interesting molecules in themselves – we describe herein an efficient synthesis of N-alkylcarboxyspiropyrans (analogous to C4SP) with alkyl chain lengths from C2 to C12, and a systematic analysis of their metal-binding properties across a range of metal cations. It was envisaged that

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

• : 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

Diversity-oriented synthesis of analogues of the novel macrocyclic peptide FR-225497 through late stage functionalization

• Jyotiprasad Mukherjee,
• Suman Sil and
• Shital Kumar Chattopadhyay

Beilstein J. Org. Chem. 2015, 11, 2487–2492, doi:10.3762/bjoc.11.270

• possess three distinct regions such as a surface recognition head group, a spacer group and a metal-binding end group which fold to provide suitable conformation necessary for their biological activity [14]. For example, compounds 2 and 4 possess identical head groups and the same spacer region; but

• metal binding. Conclusion In conclusion, we have been able to demonstrate that cross metathesis reaction on a cyclic tetrapeptide template is a viable strategy for the synthesis of a class of macrocyclic natural product-based analogues. The developed protocol may provide scope for judicious manipulation

• of the spacer region as well as the metal-binding domain attached to a particular surface recognition part present in the class of these compounds since histone deacetylase activity has been correlated to zinc-binding ability of the 8-oxo moiety in some of such compounds [25]. Moreover, the

Friedel–Crafts-type reaction of pyrene with diethyl 1-(isothiocyanato)alkylphosphonates. Efficient synthesis of highly fluorescent diethyl 1-(pyrene-1-carboxamido)alkylphosphonates and 1-(pyrene-1-carboxamido)methylphosphonic acid

• Anna Wrona-Piotrowicz,
• Janusz Zakrzewski,
• Anna Gajda,
• Tadeusz Gajda,
• Anna Makal,
• Arnaud Brosseau and
• Rémi Métivier

Beilstein J. Org. Chem. 2015, 11, 2451–2458, doi:10.3762/bjoc.11.266

• relevance which have attracted the interest of biologically-oriented chemists and biochemists [9][10][11][12]. Furthermore, the phosphonate group offers various possibilities of metal binding or anchoring to solid surfaces [13][14][15][16][17][18][19][20]. For our purposes we chose pyrene as a model arene

Self-assembly of heteroleptic dinuclear metallosupramolecular kites from multivalent ligands via social self-sorting

• Christian Benkhäuser and
• Arne Lützen

Beilstein J. Org. Chem. 2015, 11, 693–700, doi:10.3762/bjoc.11.79

• the maximum occupancy rule [24] is obeyed which open-chain oligomeric or polymeric species do not do. Results and Discussion Design and synthesis Our strategy asks for the design of rigid multivalent ligands that present their metal binding sites in a way that the formation of discrete macrocyclic or

• assembly with tetrahedral-coordinated metal ions because they are preorganized in a way that they present their metal binding sites in an almost orthogonal fashion and in the right distance. In fact, (rac)-1 has been synthesized before by E. Yashima from commercially available 5-aminophenanthroline (3) [25

Organophosphorus chemistry

• Paul R. Hanson

Beilstein J. Org. Chem. 2014, 10, 2087–2088, doi:10.3762/bjoc.10.217

• number of important fields. Among the more prominent features that elevate their status as a unique and versatile class of compounds, include variable oxidation states, multivalency, asymmetry and metal-binding properties. Their presence in bioactive natural products, endogenous biomolecules, small

Towards allosteric receptors – synthesis of β-cyclodextrin-functionalised 2,2’-bipyridines and their metal complexes

• Christopher Kremer,
• Gregor Schnakenburg and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 814–824, doi:10.3762/bjoc.10.77

• well defined [Zn(1)2] complexes which, together with the NMR data, proof that zinc(II) ions are suitable to act as an effector for 1. Changing the substitution pattern to 6,6’ like in ligand 2, however, makes it impossible to form a 1:2 complex due to the steric crowding around the metal binding site

• sterically congested metal binding site of 3. Hence, we have to conclude that, unfortunately, we have not succeeded in finding a suitable effector for this ligand yet. Mixing of preformed complexes [Zn(22)]2+ and [Cu(22)]+ with 1 in a 1:1 ratio, however, afforded the desired heteroleptic complexes [Cu(22)(1

Intermediates in monensin biosynthesis: A late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding

• Wolfgang Hüttel,
• Jonathan B. Spencer and
• Peter F. Leadlay

Beilstein J. Org. Chem. 2014, 10, 361–368, doi:10.3762/bjoc.10.34

• specifically-blocked mutant of wild-type S. cinnamonensis [24] or from a wild-type fermentation conducted in the presence of the potent methyltransferase inhibitor metapyrone [25]. To gain further insight into the metal-binding properties of demethylmonensin A and dehydroxymonensin A, they were each

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• + to 3a and 3k [48]. Again, Na+ was bound preferentially, with computer models suggesting that this was due to the depth to which the cation was drawn into the macrocyclic cavity when in the cone conformer. 4.1.3 Transition-metal complexes: The first example of transition-metal binding to an oxacalix[3

An enantiomerically pure siderophore type ligand for the diastereoselective 1 : 1 complexation of lanthanide(III) ions

• Markus Albrecht,
• Olga Osetska,
• Thomas Abel,
• Gebhard Haberhauer and
• Eva Ziegler

Beilstein J. Org. Chem. 2009, 5, No. 78, doi:10.3762/bjoc.5.78

• enantiomerically pure “non-natural” peptide moiety [25], which organizes three tridenate metal binding sites in one direction [26][27][28]. The synthesis of the compound is facile and utilizes a multiple Claisen-rearrangement reaction as introduced by Hiratani as the keystep [29][30]. UV and CD titration

The first salen- type ligands derived from 3',5'-diamino- 3',5'-dideoxythymidine and -dideoxyxylothymidine and their corresponding copper(II) complexes

• Daniel Koth,
• Michael Gottschaldt,
• Helmar Görls and
• Karolin Pohle

Beilstein J. Org. Chem. 2006, 2, No. 17, doi:10.1186/1860-5397-2-17

• 3',5'-diaminothymidines in ribo- and xylo-configuration represent the first nucleosides bearing salen-type chelating units at these positions. With their synthesis a new class of tetradentate chiral ligands with interesting features could be obtained. The chiral sugar moiety is close to the metal

• binding site and the N-glycosidic bound thymine provides an additional chiral information and steric shielding. After the ligands had been added to a mixture of copper(II) acetate in THF the complexes were formed within a few minutes resulting in a dark green solution (Scheme 2). All four ligands 8–11

Crystal engineering of analogous and homologous organic compounds: hydrogen bonding patterns in trimethoprim hydrogen phthalate and trimethoprim hydrogen adipate

• Packianathan Thomas Muthiah,
• Savarimuthu Francis,
• Urszula Rychlewska and
• Beata Warżajtis

Beilstein J. Org. Chem. 2006, 2, No. 8, doi:10.1186/1860-5397-2-8

• role in biological structure and functions, molecular design, etc [6]. Recently Sijbesma and Meijer have investigated the role of quadruple hydrogen bonded network in the various heterocyclic compounds [7]. Pyrimidine derivatives offer multiple metal binding modes and have remarkable hydrogen bonding