Interaction of the DNA bases and their mononucleotides with pyridine-2-carbaldehyde thiosemicarbazonecopper(II) complexes. Structure of the cytosine derivative.
Experimental studies of the binding interactions of [CuL(NO(3))] and [{CuL'(NO(3))}(2)] (HL=pyridine-2-carbaldehyde thiosemicarbazone, and HL'=pyridine-2-carbaldehyde 4N-methylthiosemicarbazone) with adenine, guanine, cytosine, thymine and their mononucleotides (dNMP), 2-deoxyadenosine-5'-monophosphate, (dAMP), 2'-deoxyguanosine-5'-monophosphate, (dGMP), 2'-deoxycytidine-5'-monophosphate (dCMP), and thymidine-5'-monophosphate (dTMP) have been carried out in aqueous solution at pH 6.0, I=0.1M (NaClO(4)) and T=25 degrees C. The complexation constants of these compounds, calculated by Hildebrand-Benesi plots for the dye binding, D, ([CuL] or [CuL']) to the nucleobases or nucleotides (P), have shown two linear stretches in adenine, guanine, dAMP and dGMP. The data were analyzed in terms of formation of 1:1 DP and 1:2 DP(2) complexes with increasing purine base or nucleotide content. For cytosine and dCMP only 1:1 complexes have been observed, whereas for thymine and dTMP such complex structures were not observed. The [CuL(Hcyt)](ClO(4)) cytosine derivative has been isolated and characterized. The crystal structure consists of perchlorate ions and [CuL(Hcyt)](+) monomers attached by hydrogen bond, chelate pi-ring and anion-pi interactions. The Cu(2+) ions bind to the NNS chelating moiety of the thiosemicarbazone ligand and the cytosine N13 site (N3, most common notation) yielding a square-planar geometry. A pseudocoordination to the cytosine O12 site (=O2) can also be considered.
García
Begoña
B
Departamento de Química, Universidad de Burgos, 09001 Burgos, Spain. begar@ubu.es
Garcia-Tojal
Javier
J
Ruiz
Rebeca
R
Gil-García
Ruben
R
Ibeas
Saturnino
S
Donnadieu
Bruno
B
Leal
José M
JM
D000225:Adenine / Q000737:chemistry; D000227:Adenine Nucleotides / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003596:Cytosine / Q000737:chemistry; D003597:Cytosine Nucleotides / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry; D006150:Guanine Nucleotides / Q000737:chemistry; D009711:Nucleotides / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D011687:Purines / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*; D013882:Thiosemicarbazones / Q000737:chemistry*
D000227:Adenine Nucleotides; D003597:Cytosine Nucleotides; D006150:Guanine Nucleotides; D009711:Nucleotides; D009942:Organometallic Compounds; D011687:Purines; D011725:Pyridines; D011743:Pyrimidines; D013882:Thiosemicarbazones; C432864:pyridine-2-carbaldehyde; D006147:Guanine; D003300:Copper; D003596:Cytosine; D004247:DNA; D000225:Adenine