TY - JOUR
T1 - Selective Formation of Intramolecular Hydrogen-Bonding Palladium(II) Complexes with Nucleosides Using Unsymmetrical Tridentate Ligands
AU - Mitsuhashi, Ryoji
AU - Imai, Yuya
AU - Suzuki, Takayoshi
AU - Hayashi, Yoshihito
N1 - Funding Information:
Funding: This work was partly funded by Sakigake Project 2020 of Kanazawa University. This work was partly supported by a Grant-in-aid for Scientific Research No. 19K15525 from MEXT, Japan.
Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2022/4/1
Y1 - 2022/4/1
N2 - Three palladium(II) complexes with amino-amidato-phenolato-type tridentate ligands were synthesized and characterized by1H NMR spectroscopy and X-ray crystallography. The strategic arrangement of a hydrogen-bond donor and acceptor adjacent to the substitution site of the PdII complex allowed the selective coordination of nucleosides. Among two pyrimidine-nucleosides, cytidine and 5-methyluridine, cytidine was successfully coordinated to the PdII complex while 5-methyluridne was not. On the other hand, both purine-nucleosides, adenosine and guanosine, were coordinated to the PdII complex. As purines have several coordination sites, adenosine afforded three kinds of coordination isomers expected from the three different donors. However, guanosine afforded a sole product according to the ligand design such that the formation of double intramolecular hydrogen-bond strongly induced the specific coordination by N1-position of guanine moiety. Furthermore, the preference of the nucleosides was evaluated by scrambling reactions. It was found that the preference of guanosine is nearly twice as high as adenosine and cytidine, owing to the three-point interaction of a coordination bond and two hydrogen bonds. These results show that the combination of a coordination and hydrogen bonds, which is reminiscent of the Watson–Crick base pairing, is an effective tool for the precise recognition of nucleosides.
AB - Three palladium(II) complexes with amino-amidato-phenolato-type tridentate ligands were synthesized and characterized by1H NMR spectroscopy and X-ray crystallography. The strategic arrangement of a hydrogen-bond donor and acceptor adjacent to the substitution site of the PdII complex allowed the selective coordination of nucleosides. Among two pyrimidine-nucleosides, cytidine and 5-methyluridine, cytidine was successfully coordinated to the PdII complex while 5-methyluridne was not. On the other hand, both purine-nucleosides, adenosine and guanosine, were coordinated to the PdII complex. As purines have several coordination sites, adenosine afforded three kinds of coordination isomers expected from the three different donors. However, guanosine afforded a sole product according to the ligand design such that the formation of double intramolecular hydrogen-bond strongly induced the specific coordination by N1-position of guanine moiety. Furthermore, the preference of the nucleosides was evaluated by scrambling reactions. It was found that the preference of guanosine is nearly twice as high as adenosine and cytidine, owing to the three-point interaction of a coordination bond and two hydrogen bonds. These results show that the combination of a coordination and hydrogen bonds, which is reminiscent of the Watson–Crick base pairing, is an effective tool for the precise recognition of nucleosides.
KW - crystal structure
KW - hydrogen-bonding interactions
KW - nucleoside
KW - palladium(II) complex
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U2 - 10.3390/molecules27072098
DO - 10.3390/molecules27072098
M3 - Article
C2 - 35408496
AN - SCOPUS:85127468311
VL - 27
JO - Molecules
JF - Molecules
SN - 1420-3049
IS - 7
M1 - 2098
ER -