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The acylation reactivity of RNA 2'-OH groups has established broadly useful for structural mapping and conjugation of RNA. We herein investigate various effects that control the reactivity of the RNA 2’-OH. Our  Kinetics experiments reveal the importance of steric, electrostatic and inductive effects in RNA acylation.

13. B. Jash, E. T. Kool*; “Conjugation of RNA via 2’-OH acylation: Mechanisms determining nucleotide reactivity

Chemical Communication 2022, 58, 3693-3696. 

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Reversible quinone methide acylating reagents are designed for the rapid control of RNAs (e.g. mRNA) in vitro and in cells. The described  caging methods should be compatible with previously established methods and could potentially be synergistically combined for additional control and circuit design.

12. H. S. Park, B. Jash, L. Xiao, Y. W. Jun, E. T. Kool*; “Control of RNA with quinone methide reversible acylating reagents”  

Organic & Biomolecular Chemistry 2021,19, 8367-8376.


9. B. Jash, J. Müller*; “Stable Hg(II)-mediated base pairs with a phenanthroline-derived nucleobase surrogate in antiparallel-stranded DNA


Journal of Biological Inorganic Chemistry 2020, 25, 647-654.

Hg(II)-mediated base pairs formed from an artificial mispair are a rarity. The P–Hg(II)–P pair represents the first example of a Hg(II)-mediated base pair comprising a bidentate ligand and thereby increases the pool of artificial nucleobase capable of forming Hg(II)-mediated base pairs. The P–Hg(II)–T pair turns out to be the most stabilizing non-organometallic Hg(II)-mediated base pair reported to date, with an increase in the melting temperature 14.5(6) °C. Hence, it fulfils the initial objective of creating a metal-mediated base pair that is more stabilizing than the T–Hg(II)–T base pair (ΔTm up to 10 °C, depending on the DNA sequence). 


8. B. Jash, J. Müller*;“A stable Zinc(II)-mediated base pair in parallel-stranded DNA duplex

Journal of Inorganic Biochemistry 2018, 186, 301-306. (Open Access)

An artificial nucleoside analog based on the ligand 1H-imidazo[4,5-f][1,10]phenanthroline was applied in the first generation of a Zn(II)-mediated base pair in parallel-stranded DNA. The tetrahedrally distorted homoleptic Zn(II) complex is formed enantiospecifically, most likely induced by the helical chirality of the DNA duplex. Stable Zn(II)-mediated base pairing was achieved at three different pH values (acidic, near-neutral, alkaline), indicating the robustness of the metal-mediated base pair.

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7. B. Jash, J. Müller*;“Concomitant site-specific incorporation of Silver(I) and Mercury(II) ions into a DNA duplex

Chemistry – A European Journal 2018, 24, 10636-10640.

Using only one type of artificial nucleobase, two different soft metal ions were site-specifically introduced into a DNA duplex at the same time. The specificity of the metal array relies on the different pKa values of the pyrimidine N3 positions and can controlled by changing the pH. The fact that only one artificial nucleoside analogue is required for this heterometallic assembly will simplify its application, for example, in the context of introducing different metal-based functionalities into DNA origami.


6. B. Jash, J. Müller*; “Stable Copper(I)-mediated base pair in DNA


Angewandte Chemie International Edition 2018, 57, 9524-9527.

Highlighted in annual overview of Inorganic chemistry 2018 in Nachrichten aus der Chemie.

The first Cu(I)-mediated base pair in a nucleic acid is reported, as was unequivocally confirmed by an elegant combination of in situ generation and removal of Cu(I) and Cu(II). This first report of a copper(I)-mediated base pair adds metal-based diversity to the field and consequently opens up the range of possible applications of metal-modified nucleic acids. In fact, copper is the first metal ion to be involved in the formation of stable metal-mediated base pairs in two different oxidation states. 

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5. B. Jash, J. Müller*; “Metal-mediated base pairs: from characterization to application” (Minireview)

Chemistry – A European Journal 2017, 23, 17166-17178.

This minireview introduces into the field of metal-mediated base pairing by presenting a tutorial-type overview of the considerations taken when devising a new metal-mediated base pair. In addition, it summarizes recent advancements in applications of metal-modified nucleic acids.

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4. B. Jash, J. Müller*; “Application of a metal-mediated base pair to the detection of medicinally relevant single nucleotide polymorphisms

European Journal of Inorganic Chemistry 2017, 3857-3861. (Open Access)


Selected as very important paper. Cover picture and Cover profile.

Highlighted in ChemistryViews. Highlighted in EurJIC’s Dutch-German virtual issue.

Medicinally relevant single nucleotide polymorphisms (SNPs) based on a C→T or T→C transition can be detected by using a molecular beacon that depends on the formation of a metal‐mediated base pair involving a cytosine residue.


3. B. Jash, P. Scharf, N. Sandmann, C. Fonseca Guerra, D. A. Megger, J. Müller*; “A metal-mediated base pair that discriminates between the canonical pyrimidine nucleobases

Chemical Science 2017, 8, 1337-1343. (Open Access)

A molecular beacon with a turn-on fluorescence signal has been developed depending on the formation of a metal-mediated base pair. The nucleoside analog P is capable of discriminating between the canonical nucleobases cytosine and thymine. The beacon is based on the formation of a stable Ag+-mediated base pair between P and cytosine, whereas the presence of Ag+ strongly destabilizes nucleic acids comprising an artificial base pair between P and thymine.

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2. B. Jash, J. Neugebauer, J. Müller*; “Enantiospecific formation of metal-mediated base pair inside a DNA duplex

Inorganica Chimica Acta 2016, 452, 181-187. 

Invited contribution to a special issue on “Metal-Nucleic Acid Interactions

A chiral Ag(I)-mediated base pair involving achiral phenanthroline-derived nucleobases is formed enantiospecifically within a B-DNA duplex. This was established in a combined computational and experimental approach by means of circular dichroism spectroscopy. We predict that all other non-planar metal-mediated base pairs comprising two bidentate ligands exhibit a related preference for one enantiomer of the chiral metal complex.


1. P. Scharf,§ B. Jash,§ J. A. Kuriappan, M. P. Waller, J. Müller*; “Sequence-dependent duplex stabilization upon formation of a metal-mediated base pair” (§equal first author contribution)

Chemistry – A European Journal 2016, 22, 295-301.

A strong effect of the neighboring base pairs and the next base pairs but one on the thermal stabilization induced by a novel metal-mediated base pair has been observed that was explained with the aid of QM/MM calculations. The results indicated that, in addition to the stabilizing effect that results from the formation of coordinative bonds, destabilizing effects may occur when the artificial base pair does not fit optimally into the surrounding B-DNA duplex.

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