title: Self-assembled copper(II) metallacycles derived from asymmetric Schiff base ligands: efficient hosts for ADP/ATP in phosphate buffer.
abstract: Novel asymmetric Schiff base ligands 2-{[3-(3-hydroxy-1-methyl-but-2-enylideneamino)-2,4,6-trimethylphenylimino]-methyl}-phenol (H2L(1)) and 1-{[3-(3-hydroxy-1-methyl-but-2-enylideneamino)-2,4,6-trimethylphenylimino]-methyl}-naphthalen-2-ol (H2L(2)) possessing dissimilar N,O-chelating sites and copper(ii) metallacycles (CuL(1))4 (1) and (CuL(2))4 (2) based on these ligands have been described. The ligands and complexes have been thoroughly characterized by satisfactory elemental analyses, and spectral (IR, (1)H, (13)C NMR, ESI-MS, UV/vis) and electrochemical studies. Structures of H2L(2) and 1 have been unambiguously determined by X-ray single crystal analyses. The crystal structure of H2L(2) revealed the presence of two distinct N,O-chelating sites on dissimilar cores (naphthalene and β-ketoaminato groups) offering a diverse coordination environment. Metallacycles 1 and 2 having a cavity created by four Cu(ii) centres coordinated in a homo- and heteroleptic fashion with respective ligands act as efficient hosts for adenosine-5'-diphosphate (ADP) and adenosine-5'-triphosphate (ATP) respectively, over other nucleoside polyphosphates (NPPs). The disparate sensitivity of these metallacycles toward ADP and ATP has been attributed to the size of the ligands assuming diverse dimensions and spatial orientations. These are attuned for π-π stacking and electrostatic interactions suitable for different guest molecules under analogous conditions, metallacycle 1 offers better orientation for ADP, while 2 for ATP. The mechanism of the host-guest interaction has been investigated by spectral and electrochemical studies and supported by molecular docking studies.
authors.affiliation: Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi-221 005, India. dspbhu@bhu.ac.in dsprewa@yahoo.com.
authors.forename: Amit
authors.initials: A
authors.lastname: Kumar
authors.forename: Rampal
authors.initials: R
authors.lastname: Pandey
authors.forename: Ashish
authors.initials: A
authors.lastname: Kumar
authors.forename: Rakesh Kumar
authors.initials: RK
authors.lastname: Gupta
authors.forename: Mrigendra
authors.initials: M
authors.lastname: Dubey
authors.forename: Akbar
authors.initials: A
authors.lastname: Mohammed
authors.forename: Shaikh M
authors.initials: SM
authors.lastname: Mobin
authors.forename: Daya Shankar
authors.initials: DS
authors.lastname: Pandey
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry* / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000737:chemistry* / Q000378:metabolism; D002021:Buffers; D056831:Coordination Complexes / Q000737:chemistry* / Q000378:metabolism; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D008024:Ligands; D010710:Phosphates / Q000737:chemistry* / Q000378:metabolism; D012545:Schiff Bases / Q000737:chemistry / Q000378:metabolism
chemical_list: D002021:Buffers; D056831:Coordination Complexes; D008024:Ligands; D010710:Phosphates; D012545:Schiff Bases; D000244:Adenosine Diphosphate; D003300:Copper; D000255:Adenosine Triphosphate