Nedaossadat Mirzadeh

Synthesis and structures of cyclic gold complexes containing diphosphine ligands and luminescent properties of the high nuclearity species

A mixture of cyclic gold(I) complexes [Au(2)(μ-cis-dppen)(2)]X(2) (X = OTf 1, PF(6)3) and [Au(cis-dppen)(2)]X (X = OTf 2, PF(6)4) is obtained from the reaction of [Au(tht)(2)]X (tht = tetrahydrothiophene) with one equivalent of cis-dppen [dppen = 1,2-bis(diphenylphosphino)ethylene]. The analogous reaction with trans-dppen or dppa [dppa = bis(diphenylphosphino)acetylene] affords the cyclic trinuclear [Au(3)(μ-trans-dppen)(3)]X(3) (X = OTf 11, PF(6)12) and tetranuclear [Au(4)(μ-dppa)(4)]X(4) (X = OTf 13, PF(6)14, ClO(4)15) gold complexes, respectively. Recrystallization of 15 from CH(2)Cl(2)/MeOH yielded a crystal of the octanuclear gold cluster [Au(8)Cl(2)(μ-dppa)(4)](ClO(4))(2)16. Attempts to prepare dicationic binuclear gold(II) species from the reaction of a mixture of 3 and 4 with halogens gave a mixture of products, the components of which confirmed to be acyclic binuclear gold(I) [Au(2)X(2)(cis-dppen)] (X = I 5, Br 7) and cyclic mononuclear gold(III) [AuX(2)(cis-dppen)]PF(6) (X = I 6, Br 8) complexes. Complexes 11-14 reveal weak emission in butyronitrile glass at 77 K, but they are non-emissive at room temperature. Ab initio modelling was performed to determine the charge state of the gold atoms involved. Extensive structural comparisons were made to experimental data to benchmark these calculations and rationalize the conformations.

Self-Assembled Functional Nanostructure of Plasmid DNA with Ionic Liquid [Bmim][PF6]: Enhanced Efficiency in Bacterial Gene Transformation

The electrostatic interaction between the negatively charged phosphate groups of plasmid DNA and the cationic part of hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]), initiates spontaneous self-assembly to form the functional nanostructures made up of DNA and ionic liquid (IL). These functional nanostructures were demonstrated as promising synthetic nonviral vectors for the efficient bacterial pGFP gene transformation in cells. In particular, the functional nanostructures that were made up of 1 μL of IL ([Bmim][PF6]) and 1 μg of plasmid DNA can increase the transformation efficiency by 300-400% in microbial systems, without showing any toxicity for E. coli DH5α cells. (31)P nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron (XPS) spectroscopic analysis revealed that the electrostatic interaction between negatively charged phosphate oxygen and cationic Bmim(+) tends to initiate the self-assembly process. Thermogravimetric analysis of the DNA-IL functional nanostructures showed that these nanostructures consist of ∼16 wt % ionic liquid, which is considered to provide the stability to the plasmid DNA that eventually enhanced the transformation efficiency.

Anti-cancer gold(I) phosphine complexes: Cyclic trimers and tetramers containing the P-Au-P moiety

We report the application of cationic tri- and tetra-nuclear gold(I) phosphine complexes [Au3(μ-dppen)3]X3 and [Au4(μ-dppa)4]X4 (X=OTf, PF6) [OTf=trifluoromethanesulfonate, dppen=trans-1,2-bis(diphenylphosphino)ethene, dppa=bis(diphenylphosphino)acetylene] for cancer treatment. The results of cytotoxicity tests on four different cancer cells [prostate (DU145), cervical (HeLa), breast (MDAMB-231) and fibro sarcoma (HT1080)] indicate these complexes possess remarkable tumor cell growth inhibitory effects and high selectivity towards cancer cells. The anti-tumor mechanism of the tri- and tetra-nuclear gold(I) complexes has also been investigated.

Different solvates of the dinuclear cyclometallated gold(I) complex [Au2(μ-2-C6H4AsMe2)2]: a computational study insight into solvent-effected optical properties.

Two solvates of an arsena-aura-metallocyclic molecule, which, apart from the different solvents, have the same molecular stoichiometry, display different optical properties. We develop an ab initio model, benchmarked against X-ray diffraction experiment, to explore the possible causes of this change in behavior. We study the bonding and electronic properties of the crystals, their local environments, and consider possible effects of the solvents used for crystallization.

Synthesis of gold(I) phosphine complexes containing the 2-BrC6F4PPh2 ligand: Evaluation of anticancer activity in 2D and 3D spheroidal models of HeLa cancer cells

Newly synthesised mononuclear gold complexes containing the 2-BrC6F4PPh2 ligand have been fully characterised and their anticancer activity towards five human tumor [prostate (PC3), glioblastoma (U87MG), cervical (HeLa), fibrosarcoma (HT1080), ovarian (SKOV-3)] and normal human embryonic kidney (Hek-293T) cell lines investigated. Some of the synthesised gold complexes displayed higher cytotoxicity than cisplatin towards PC-3, HeLa and U87MG cells and inhibited the thioredoxin reductase (TrxR) enzyme, which is considered a potential target for new compounds in cancer treatment. The more physiologically relevant tumor spheroid assay demonstrated the superior potency of these gold phosphine complexes in inhibiting the growth of cervical carcinoma cell line HeLa (3D) spheroidal models. The mechanism of cell death was shown to be apoptotic cell death through cell cycle arrest, mitochondrial membrane depolarisation and increased ROS production.

Trinuclear Mixed-valent Gold Complexes Derived from 2-C 6 F 4 PPh 2 : Phosphine Oxide Complexes of Gold(III) and an ortho-Metallated Complex of Gold(I)

Crystals of two mixed-valent gold complexes [(O2NO)AuI(μ-2-C6F4PPh2)AuIII{κ2-2-C6- F4P(O)Ph2}(μ-2-C6F4PPh2)AuI(ONO2)] (14) and [(O2NO)AuI(μ-2-C6F4PPh2)AuIII{κ3-2-C6F4- P(O)Ph(C6H4)}(μ-2-C6F4PPh2)AuI] (15) have been obtained from the reaction of the digold(I,III) complex [ClAuI(μ-2-C6F4PPh2)(κ2-2-C6F4PPh2)AuIIICl] (5) with, respectively, a small and a large excess of silver nitrate. Both complexes contain three, approximately collinear metal atoms, the central gold(III) atom being planar-coordinated by a chelate (O,C)-phosphine oxide formed by oxidation of 2-C6F4PPh2 and the carbon atoms of two bridging 2-C6F4PPh2 groups. In 14 each of the terminal gold(I) atoms is coordinated by a monodentate nitrate ion and the phosphorus atom of μ-2-C6F4PPh2, whereas in 15 the nitrate ion on one of the gold(I) atoms of 14 has been replaced by the carbon atom of a bridging C6H4 group derived by Ag+-promoted cyclometallation of a phenyl group on the neighbouring phosphine oxide Graphical Abstract Trinuclear Mixed-valent Gold Complexes Derived from 2-C6F4PPh2: Phosphine Oxide Complexes of Gold(III) and an ortho-Metallated Complex of Gold(I)