Photoactivation of trans diamine platinum complexes in aqueous solution and effect on reactivity towards nucleotides

We show that UVA irradiation (365 nm) of the Pt-IV complex trans,trans,trans-[(PtCl2)-Cl-IV(OH)(2)(dimethylamine) (isopropylamine)] (1), induces reduction to Pt-II photoproducts. For the mixed amine Pt-II complex, trans[(PtCl2)-Cl-II(isopropylamine)(methylamine)] (2), irradiation at 365 nm increases the rate and extent of hydrolysis, triggering the formation of diaqua species. Additionally, irradiation increases the extent of reaction of complex 2 with guanosine-5'-monophosphate and affords mainly the bis-adduct, while reactions with adenosine-5'-monophosphate and cytidine-5'-monophosphate give rise only to mono-nucleotide adducts. Density Functional Theory calculations have been used to obtain insights into the electronic structure of complexes 1 and 2, and their photophysical and photochemical properties. UVA-irradiation can contribute to enhanced cytotoxic effects of diamine platinum drugs with trans geometry

2-Amino-4-methyl­pyridinium 2-hy­droxy­benzoate

The asymmetric unit of the title mol­ecular salt, C6H9N2 +·C7H5O3 −, contains two cations and two anions. Both the salicylate anions contain an intra­molecular O—H⋯O hydrogen bond, which generates an S(6) ring. Both the 2-amino-4-methyl­pyridine mol­ecules are protonated at their pyridine N atoms. In the crystal, both cations form two N—H⋯O hydrogen bonds to their adjacent anions, forming ion pairs. Further N—H⋯O links generate sheets lying parallel to the ab plane. In addition, weak C—H⋯O bonds and aromatic π–π stacking inter­actions [centroid–centroid distances = 3.5691 (9) and 3.6215 (9) Å] are observed between the cations and anions

trans-Dichloridobis(2-methyl­aniline-κN)palladium(II)

In the title compound, [PdCl2(C7H9N)2], the Pd atom is situated on an inversion centre and displays a distorted square-planar coordination environment. The crystal structure displays weak inter­molecular N—H⋯Cl hydrogen bonding

Interactions between Anticancertrans-Platinum Compounds and Proteins: Crystal Structures and ESI-MS Spectra of Two Protein Adducts of trans-(Dimethylamino)(methylamino)dichloridoplatinum(II)

The adducts formed between trans- (dimethylamino)(methylamino)dichloridoplatinum(II), [t-PtCl2(dma)(ma)], and two model proteins, i.e., hen egg white lysozyme and bovine pancreatic ribonuclease, were independently characterized by X-ray crystallography and electrospray ionization mass spectrometry. In these adducts, the PtII center, upon chloride release, coordinates either to histidine or aspartic acid residues while both alkylamino ligands remain bound to the metal. Comparison with the cisplatin derivatives of the same proteins highlights for [t-PtCl2(dma)(ma)] a kind of biomolecular metalation remarkably different from that of cisplatin

2-Amino-5-methyl­pyridinium picolinate 0.63-hydrate

The asymmetric unit of the title compound, C6H9N2 +·C6H4NO2 −·0.63H2O, contains two crystallographically independent 2-amino-5-methyl­pyridinium cations, a pair of picolinate anions and two water mol­ecules, one with an occupancy of 0.25. Both the 2-amino-5-methyl­pyridine mol­ecules are protonated at the pyridine N atoms. In the crystal structure, the cations, anions and water mol­ecules are linked via N—H⋯O, N—H⋯N and O—H⋯O hydrogen bonds, as well as by C—H⋯O contacts, forming a chain along the b axis. In addition, weak π–π inter­actions are observed between pyridinium rings, with centroid–centroid distances of 3.5306 (13) Å

One-dimensional Cooper pairing

We study electron pairing in a one-dimensional (1D) fermion gas at zero temperature under zero- and finite-range, attractive, two-body interactions. The binding energy of Cooper pairs (CPs) with zero total or center-of-mass momentum (CMM) increases with attraction strength and decreases with interaction range for fixed strength. The excitation energy of 1D CPs with nonzero CMM display novel, unique properties. It satisfies a dispersion relation with \textit{two} branches: a\ phonon-like \textit{linear }excitation for small CP CMM; this is followed by roton-like \textit{quadratic} excitation minimum for CMM greater than twice the Fermi wavenumber, but only above a minimum threshold attraction strength. The expected quadratic-in-CMM dispersion \textit{in vacuo }when the Fermi wavenumber is set to zero is recovered for \textit{any% } coupling. This paper completes a three-part exploration initiated in 2D and continued in 3D.Comment: 12 pages, 6 figure

Mononuclear Pd(II) and Pt(II) complexes with an α-N-heterocyclic thiosemicarbazone: Cytotoxicity, solution behaviour and interaction: Versus proven models from biological media

Two Pd(ii) and Pt(ii) complexes with two pyrrol-2-carbaldehyde N-p-chlorophenylthiosemicarbazone ligands are designed and characterized showing mononuclear structures. An important pharmacological property for both compounds is the high selectivity for tumor cells and a lack of activity in healthy cells. The Pd(ii) compound shows a higher antitumor activity and selectivity than the Pt(ii) compound. Both complexes present a variety of biological interactions: with DNA models (pBR322 and CT DNA), proteins (lysozyme and RNase) and other biological targets like proteosome. Our results show that the Pd(ii) complex is a more interesting candidate for potential anticancer therapies than the Pt(ii) complex, and we provide new insight into the design and synthesis of palladium compounds as potential antitumor agents.This work was supported by the following grants for the Spanish MINECO: SAF-2012-34424, CTQ2015-68779R and CTQ2015-70371-RED

2-Amino-5-bromo­pyridinium 3-carb­oxy-4-hy­droxy­benzene­sulfonate

The asymmetric unit of the title salt, C5H6BrN2 +·C7H5O6S−, contains two independent 2-amino-5-bromo­pyridinium cations and two independent 3-carb­oxy-4-hy­droxy­benzene­sulfonate anions. The hy­droxy and carboxyl groups of the anions are involved in intra­molecular O—H⋯O hydrogen bonds, which generate S(6) ring motifs. In the crystal structure, the ions are linked by N—H⋯O and O—H⋯O hydrogen bonds into a two-dimensional network parallel to (110). Adjacent networks are linked via C—H⋯O hydrogen bonds