Anticancer diiron aminocarbyne complexes with labile N-donor ligands.

The novel diiron amine complexes [FeCp(CO)(NHR')(μ-CO){μ-CN(Me)(Cy)}]CFSO [R' = H, 3; Cy, 4; CHCHNH, 5; CHCHNMe, 6; CHCH(4-CHOMe), 7; CHCH(4-CHOH), 8; Cp = η-CH, Cy = CH = cyclohexyl] were synthesized in 49-92 % yields from [FeCp(CO)(μ-CO){μ-CN(Me)(Cy)}]CFSO, 1a, using a straightforward two-step procedure. They were characterized by IR and multinuclear NMR spectroscopy, and the structure of 7 was confirmed through X-ray diffraction analysis. Complexes 3-8 and the acetonitrile adducts [FeCp(CO)(NCMe)(μ-CO){μ-CN(Me)(R)}]CFSO (R = Cy, 2a; Me, 2b; Xyl = 2,6-CHMe, 2c) were assessed for their water solubility, octanol-water partition coefficient and stability in physiological-like solutions.

Triiron Complex with -Ferrocenyl Aminocarbyne Ligand Bridging a Diiron Core: DFT, Electrochemical, and Biological Insights.

The first -ferrocenyl aminocarbyne complex, [FeCp(CO)(μ-CO){μ-CN(Me)(Fc)}]CFSO (), was synthesized with an 88% yield from [FeCp(CO)], isocyanoferrocene (CNFc), and methyl triflate. The synthesis proceeded through the intermediate formation of [FeCp(CO)(CNFc)], . Multinuclear NMR experiments revealed the presence of cis and trans isomers for in organic solvents, in agreement with DFT outcomes.

Diiron Aminocarbyne Complexes with NCE Ligands (E = O, S, Se).

Diiron μ-aminocarbyne complexes [FeCp(NCMe)(CO)(μ-CO){μ-CN(Me)(R)}]CFSO (R = Xyl, ; R = Me, ; R = Cy, ; R = CHPh, ), freshly prepared from tricarbonyl precursors , reacted with NaOCN (in acetone) and NBuSCN (in dichloromethane) to give [FeCp(k-NCO)(CO)(μ-CO){μ-CN(Me)(R)}] (R = Xyl, ; Me, ; Cy, ) and [FeCp(k-NCS)(CO)(μ-CO){μ-CN(Me)(CHPh)}], in 67-81% yields via substitution of the acetonitrile ligand. The reaction of with KSeCN in THF at reflux temperature led to the cyanide complexes [FeCp(CN)(CO)(μ-CO){μ-CNMe(R)}], - (45-67%). When the reaction of with KSeCN was performed in acetone at room temperature, subsequent careful chromatography allowed the separation of moderate amounts of [FeCp(k-SeCN)(CO)(μ-CO){μ-CN(Me)(Xyl)}], , and [FeCp(k-NCSe)(CO)(μ-CO){μ-CN(Me)(Xyl)}], .

Alkyne-alkenyl coupling at a diruthenium complex.

Dimetallic complexes are suitable platforms for the assembly of small molecular units, and the reactivity of bridging alkenyl ligands has been widely investigated to model C-C bond forming processes. Here, we report the unusual coupling of an alkenyl ligand, bridging coordinated on a diruthenium scaffold, with a series of alkynes, revealing two possible outcomes. The diruthenium complex [RuCp(Cl)(CO)(μ-CO){μ-η:η-C(Ph)CH(Ph)}], 2, was prepared in two steps from [RuCp(CO)(μ-CO){μ-η:η-C(Ph)CH(Ph)}]BF, [1]BF4, in 69% yield.

η-Coordinated ruthenabenzenes from three-component assembly on a diruthenium μ-allenyl scaffold.

The room temperature reactions with internal alkynes, RCCR, of the μ-allenyl acetonitrile complex [RuCp(CO)(NCMe){μ-η:η-CHCCMe}]BF (1-NCMe), freshly prepared from the tricarbonyl precursor [RuCp(CO){μ-η:η-CHCCMe}]BF, 1, proceeded with alkyne insertion into ruthenium-allenyl bond and allenyl-CO coupling, affording compounds [RuCp(CO){μ-η:η-C(R)C(R)CHC(CMeCH)C(OH)}]BF (R = Ph, 2; R = COMe, 3; R = COEt, 4) in 83-94% yields. Deprotonation of 2-4 by triethylamine gave [RuCp(CO){μ-η:η-C(R)C(R)CHC(CMeCH)C(O)}] (R = Ph, 5; R = COMe, 6; R = COEt, 7) in 75-88% yields, and 2-4 could be recovered upon HBF·EtO addition to 5-7. All the products, 2-7, were fully characterized by elemental analysis, IR and multinuclear NMR spectroscopy.

Cyanide-alkene competition in a diiron complex and isolation of a multisite (cyano)alkylidene-alkene species.

The μ-(amino)alkylidyne complex [FeCp(CO)(μ-CO){μ-CNMe(CHCHCH)}]CFSO, [1]CFSO, reacted with NBuCN in dichloromethane affording the μ-(cyano)(amino)alkylidene [FeCp(CO)(μ-CO){μ-C(CN)N(Me)(CHCHCH)}], 2, in 91% yield. Decarbonylation of 2 by using MeNO in acetone at room temperature yielded [FeCp(CO)(μ-CO){μ-κ-C(CN)N(Me)(CHCHCH)}], 3, containing a multidentate alkylidene-alkene ligand occupying both a bridging site and a terminal site, in admixture with the μ-(amino)alkylidyne cyanide product [FeCp(CN)(CO)(μ-CO){μ-CN(Me)(CHCHCH)}], 4. The reaction of the μ-(amino)alkylidyne imine complex [FeCp(CO)(μ-CO)(NHCPh){μ-CN(Me)(CHCHCH)}]CFSO, [7]CFSO, with NBuCN gave 3 with an optimized yield of 75% imine elimination.

Screening the biological properties of transition metal carbamates reveals gold(I) and silver(I) complexes as potent cytotoxic and antimicrobial agents.

We report a screening study aimed to assess for the first time the air- and water-stability and the biological potential of simple metal-carbamates. These molecular metallic species are based on elements belonging to the groups 4-5, 7-9 and 11, and tin, and are easily available from inexpensive reagents. Complexes [Ag(OCNEt)] (13-Ag) and [Au(OCNMe)(PPh)] (14-Au) resulted substantially stable in aqueous media and exhibited a potent in vitro cytotoxicity.

Diethylammonium iodide as catalyst for the metal-free synthesis of 5-aryl-2-oxazolidinones from aziridines and carbon dioxide.

The catalytic potential of ammonium halide salts was explored in the coupling reaction of a model aziridine with carbon dioxide, highlighting the superior activity of [NH2Et2]I. Then, working at room temperature, atmospheric CO2 pressure and in the absence of solvent, the [NH2Et2]I-catalyzed synthesis of a series of 5-aryl-2-oxazolidinones was accomplished in good to high yields and excellent selectivity, from 2-aryl-aziridines with N-methyl or N-ethyl groups. NMR studies and DFT calculations outlined the pivotal role of both the diethylammonium cation and the iodide anion.

Cervical cancer screening invitations in low and middle income countries: Evidence from Armenia.

Roughly 90 percent of cervical cancer deaths occur in low- and middle-income countries (LMICs), where the lack of adequate infrastructures hampers screening, while informational, cultural, and socio-economic barriers limit participation in the few programs that do exist. We conducted a field experiment with the Armenian cervical cancer screening program to determine whether, despite these barriers, the simple, economical invitation strategies adopted in high-income countries could enhance screening take-up in LMICs. We find that letters of invitation increase screening take-up, especially when there are follow-up reminders.

The chlorinating behaviour of WCl₆ towards α-aminoacids.

Cl/O interchange took place when WCl6 was allowed to interact with a series of α-aminoacids. The α-ammonium-acylchloride salts [NH2(CH2)3CHC(O)Cl][WOCl5], 1a, and [MeNH2CH2C(O)Cl][WOCl5], 1b, were afforded in ca. 55% yields from the reactions of WCl6 with, respectively, L-proline and sarcosine in CH2Cl2.

Oxido-molybdenum complexes obtained by Cl/O interchange between MoCl5 and carboxylic acids: a crystallographic, spectroscopic and computational study.

The direct interaction of MoCl5 with a series of carboxylic acids has been elucidated for the first time. The reactions proceed with release of hydrogen chloride and Cl/O interchange between the metal centre and one equivalent of organic substrate: this feature is unique in the context of the chemistry generally shown by transition metal halides with carboxylic acids. The dinuclear complexes [MoOCl2(κ(1)-CX3CO2H)(μ-Cl)]2 (X = H, 1a; X = Cl, 1b) and Mo2O2Cl6(μ-CH3CO2H), 2a, were isolated as the prevalent metal products of the 1:2 molar reactions of MoCl5 with CH3COOH and CCl3COOH.