Pyrazolylborate−Zinc−Nucleobase-Complexes, 2:¹Preparations and Structures of Tp^Cum,MeZn and Tp^Ph,MeZn Complexes

Abstract

The interactions of the nine most significant nucleobases (thymine, uracil, dihydrouracil, cytosine, adenine, guanine, diaminopurine, xanthine, hypoxanthine, in their deprotonated forms) with zinc and with themselves in pyrazolylborate zinc complexes Tp(Cum,Me)Zn-base and Tp(Ph,Me)Zn-base are described. Except for guanine, the complexes Tp*Zn-base could be isolated in all cases. Structure determinations could be performed for seven of the eight product types. Except for dihydrouracil and xanthine, the zinc ion is attached to that nitrogen of the base which in nucleosides bears the sugar moiety. In the solid state, all zinc-bound nucleobases are involved in hydrogen bonding interactions. Except for xanthine, this includes homo base pairing across a crystallographic inversion center.

Supramolecular architectures with ladder and lamellar topologies using metal-ligand coordination units via C–H···Cl and O–H···Cl hydrogen bonding

“…6a). This is an example of selfcomplementary hydrogen-bonding interactions [6,49], as observed in our earlier work with C-H···Cl hydrogenbonding interaction [28]. The dimeric units (tectons) in turn are involved in interactions with similar dimer in the adjacent layers through C-H···Cl interactions involving C-H (pyridyl-4H) and the chloride ion.…”

Zinc(II) complexes with potent cyclin-dependent kinase inhibitors derived from 6-benzylaminopurine: Synthesis, characterization, X-ray structures and biological activity

“…As for the Zn-N distances, they are nearly comparable in 3 (2.045(4) Å ) and (2.0311(18) Å ) in 4, but differ significantly as against to those determined in [Zn(AdeH + -N7)Cl 3 ], i.e., 2.094 Å [37], 2.079 Å [40] and 2.091 Å [38]. In addition to the above-mentioned Zn(II) complexes bearing adenine and its derivatives coordinated through the N7 atom of the purine ring, there were also determined the structures in which the coordination goes via N1 atom [33,41], N3 atom [35] and N9 atom [42,43,21].…”

Two isomorphous transition metal complexes containing a protonated diaminopurine ligand: diaquabis(2,6-diamino-7H-purin-1-ium-κN9)bis(homophthalato-κO)nickel(II) tetrahydrate and the cobalt(II) analogue

“…Moreover, in addition to its hydrogenbonding capabilities, the molecule can also act as a monocoordinated ligand binding to metal sites through an imidazole N atom. The coordinating capabilities of dap, however, seem to be rather poor: only one compound with the molecule binding to a metal centre appears in the Cambridge Structural Database (CSD, Version 5.31;Allen, 2002), in a Zn complex reported by Badura & Vahrenkamp (2002). In this Zn complex, the dap molecule is present with the imidazole ring completely deprotonated, behaving as a dap À anion.…”