Structural Aspects of the Coordination of Triethylphosphinegold(I) to 2-Thiouracil:  A Comparison between Theory and Experiment

Abstract

The interaction of the thionucleobase 2-thiouracil with the triethylphosphinegold(I) cation has been examined employing ab initio molecular orbital theory. Deprotonation of 2-thiouracil (2-TUH) and subsequent association with [Et3PAu]+ leads to the formation of [Et3PAu(2-TU H)]; a comparison of calculated and experimental geometric parameters reveals a high degree of agreement. The interaction of two [Et3PAu]+ cations with twice deprotonated 2-TUH indicates that the most stable dinuclear structure is one where coordination occurs via the sulfur and one of the nitrogen atoms leading to almost linear P−Au−S and P−Au−N arrangements, respectively.

Synthesis, Structure and Bactericide Activity of (Aminophosphane)gold(I) Thiolate Complexes

“…[11][12][13][14][15][16][17][18][19][20][21][22] The longer Au-P distances in the thiolate derivatives compared with those in complexes 3 [2.2187(11) Å] and 4 [2.223(2) Å] are in agreement with the higher trans influence of the thiolato ligand compared with the chlorido ligand.…”

“…The IR spectrum of solid compound 7 presents a stretching carbonyl band at 1631 cm -1 (1680 cm -1 in the free ligand), which indicates that the thiouracil is coordinated to the gold centre through the sulfur atom in the form of thiolate, and consequently there is a -C=O bond at the 4-position. [11,12] In the 1 H NMR spectrum of complex 8 a broad singlet at δ = 12.30 ppm was assigned to the NH 2 group and one doublet and one broad signal to the aromatic protons of the 2-thiocytosine group. The reactions of complex 4 with the thiols 2-mercaptopyridine (2-HSpy), 2-thiocytosine (2-HTC) or 6-thioguanine (6-HTG) and triethylamine led to the complexes 9-11, respectively (see Scheme 4).…”

Interaction between the Guanine−Cytosine Watson−Crick DNA Base Pair and Hydrated Group IIa (Mg2+, Ca2+, Sr2+, Ba2+) and Group IIb (Zn2+, Cd2+, Hg2+) Metal Cations

“…Recent developments in computer power together with more efficient codes allow application of higher level ab initio methods to the complexes of base pairs with metal cations. − ,, One possibility is to rely on the density functional theory techniques, as applied by Carloni and Andreoni to the platinated adenine−thymine base pair in the solid state . An alternative is to use the conventional correlated ab initio techniques combined with relativistic pseudopotentials. − , Recently we have studied 7-9 interactions between 15 mono- and divalent metal cations and nucleobases, as well as the Watson−Crick (WC) and reverse Hoogsteen (rH) base pairs. These calculations demonstrated that every cation has a rather unique interaction with the DNA bases and base pairs.…”

Tautomeric equilibria of 2- and 4-thiouracil in gas phase and in solvent: A density functional study

“…Actually the 2‐thiouracil is used as highly specific melanoma seeker, and it shows a mechanism of selective incorporation into growing melanins both in vitro and in vivo 15. Moreover, the triorganophosphinegold (I) complexes of 2‐thiouracil display promising antiarthritic activity 16. 4‐thiouracil presents cytostatic properties and is used as the cross‐linking agent in RNA transcriptional regulation 17.…”