A Comprehensive Analysis of the Metal–Nitrile Bonding in an Organo-Diiron System

Nitriles (N≡CR) are ubiquitous in coordination chemistry, yet literature studies on metal–nitrile bonding based on a multi-technique approach are rare. We selected an easily-available di-organoiron framework, containing both π-acceptor (CO, aminocarbyne) and donor (Cp = η5−C5H5) ligands, as a suitable system to provide a comprehensive description of the iron–nitrile bond. Thus, the new nitrile (2–12)CF3SO3 and the related imine/amine complexes (8–9)CF3SO3 were synthesized in 58–83% yields from the respective tris-carbonyl precursors (1a–d)CF3SO3, using the TMNO strategy (TMNO = trimethylamine-N-oxide). The products were fully characterized by elemental analysis, IR (solution and solid state) and multinuclear NMR spectroscopy. In addition, the structures of (2)CF3SO3, (3)CF3SO3, (5)CF3SO3 and (11)CF3SO3 were ascertained by single crystal X-ray diffraction. Salient spectroscopic data of the nitrile complexes are coherent with the scale of electron-donor power of the R substituents; otherwise, this scale does not match the degree of Fe → N π-back-donation and the Fe–N bond energies, which were elucidated in (2–7)CF3SO3 by DFT calculations.

Engaging African Men through Sexual, Reproductive Health, and Rights Interventions

This article examines how research and ideas related to so-called positive masculinities have emerged and proliferated among employees of a Dutch development organization, enabling it to establish itself as a frontrunner in engaging men in campaigns to improve sexual and reproductive health and rights (SRHR). Arguments draw on organizational ethnography conducted from September 2016 until July 2018 and analysis of discursive practices embedded in documents and training materials that have helped establish men as a new target for intervention. These ideas circulate within a Dutch-funded, globally distributed knowledge network that is for the most part invisible to the African men being targeted. At the same time, the Dutch experts developing these “men engagement” interventions are also largely unaware of how unspoken Dutch norms around gender equality, masculinity, and race are used to legitimize these interventions. This paper emphasizes the importance of considering how donor agendas and donor power work, while at the same time exploring how these elements can, often unconsciously, be inserted into programs, often skewing them in a particular direction.

Systematic evaluation of the electronic effect of aluminum-containing ligands in iridium–aluminum and rhodium–aluminum bimetallic complexes

A library of heterobimetallic complexes are investigated to determine the electron donor power of an aluminum-containing ligand on a late transition metal.

1,2-Diaryl-1,2-disodioethanes: Versatile, Highly Reactive, and Tunable Synthetic Equivalents of Sodium Metal

1,2-Diaryl-1,2-disodioethanes are easily prepared, versatile, and stable diorganometals finding application in 1,2-reductive eliminations as well as in the degradation of several persistent organic pollutants as homogeneous synthetic equivalents of a highly reactive form of Na metal. Understanding their reactivity in terms of their different electron-donor power, which is strongly affected by the nature of substituents located either on the aromatic ring(s) or on the carbanionic centers, allowed rationalization of their employment not only as chemoselective single electron transfer reducing reagents, but also as bases in the generation of enediolates of arylacetic acids bearing easily reducible carbon–halogen bonds.

Atomic Level Mechanism of the White Phosphorous Demolition by Di-iodine

A detailed mechanism of the I2-induced transformation of white phosphorus into PI3 emerges from a DFT analysis. The multi-step process implies at any stage one P P and two I I bond cleavages, associated to the formation of two P I bonds plus an in situ generated brand new I2 molecule. Significant electron transfer between atoms is observed at any step, but the reactions better define as concerted rather than redox. Along the steepest descent to the product, no significant barrier is encountered except for the very first P4 activation, which costs +14.6 kcal mol-1. At the atomic level, one first I2 molecule, a typical mild oxidant, is first involved in a linear halogen bonding interaction (XB) with one P donor, while its terminal I atom is engaged in an additional XB adduct with a second I2. Significant electron transfer through the combined diatomics allows the external I atom of the dangling I3 grouping to convey electrons into the * level of one P P bond with its consequent cleavage. This implies at some point the appearance of a six-membered ring, which alternative switches its bonding and no-bonding interactions. The final transformation of the P2I4 diphosphine into two PI3 phosphines is enlightening also for the specific role of the I substituents. In fact, it is proved that an organo-diphosphine analogue hardly undergoes the separation of two phosphines, as reported in literature. This is attributable to the particularly high donor power of the carbo-substituted P atoms, which prevents the concertedness of the reaction but favors charge separation in an unreactive ion pair. <br>

On the relation between carbonyl stretching frequencies and the donor power of chelating diphosphines in nickel dicarbonyl complexes

We unravel the mechanisms of chelation-bond formation in nickel dicarbonyl complexes with bidentate phosphines and demonstrate that σ donation drives the carbonyl stretching response to the metal–ligand bond formation.

N-type semiconducting perylene diimide based molecules for organic solar cells

ABSTRACTCore substituted perylene diimides (PDIs) are promising candidates as non-fullerene acceptor materials for organic solar cells. The functionalization of PDIs in the bay positions using chemical groups with different electron donating abilities and with steric hindrance is a versatile tool to modify both the optoelectronic properties and the morphology in the solid state.Herein we present two new PDI based molecules having bulky aromatic substituents linked into the bay positions: PDI-SF with spirobifluorene group and PDI-BSF with bithienyl-spirobifluorene moieties. The high steric hindrance of spirobifluorene reduce the tendency to form aggregates that has been identified as a limiting factor for the photovoltaic performances in PDI based solar cells.The PDI molecules were tested as electron acceptors in bulk heterojunction solar cells with P3HT as electron donor. Power conversion efficiencies (PCE) of 1.58% and 1.18% were obtained for PDI-SF and PDI-BSF devices.