Search results for "Ferro"

Phosphine Ligands Based on the Ferrocenyl Platform: Advances in Catalytic Cross-Couplings

2023

Ferrocenyl skeletons tagged with a variety of donor atoms (metalloligands) have become popular in modern metal-catalyzed organic transformations, broadening the applications. Ferrocenylphosphines, such as 1′-bis(diphenylphosphino)ferrocene (dppf), have been widely used as metalloligands in academic and industrial research, motivating further investigation into novel ferrocenylphosphine ligands. The current review concentrated non-exhaustively on emblematic applications of different ferrocenylphosphine ligands in transition metal-catalyzed cross-coupling strategies. Initially, the stereochemical aspects of the ferrocenyl skeleton, nomenclature, and applications of chiral ferrocenyl phosphine…

Manganese/polymetallic nodules: Micro-structural characterization of exolithobiontic- and endolithobiontic microbial biofilms by scanning electron mi…

2009

Polymetallic/ferromanganese nodules (Mn-nodules) provide a rich source for manganese. It is not yet known if the nodules have a biogenic or an abiogenic origin. Here we applied the technique of high-resolution scanning electron microscopy, in combination with energy dispersive X-ray spectroscopical (EDX) analysis, to trace the existence of microbial biofilms. Two spatially separated assemblies exist, the exolithobiontic- and endolithobiontic colonizations. The exolithobiontic colonization is seen in the micro-canals, which traverse the outer surface layer of the nodules and are formed by elongated filamentous organisms, which show no signs of mineralization. In the center of the nodules thr…

Towards Low-Cost Pavement Condition Health Monitoring and Analysis Using Deep Learning

2020

Governments are faced with countless challenges to maintain conditions of road networks. This is due to financial and physical resource deficiencies of road authorities. Therefore, low-cost automated systems are sought after to alleviate these issues and deliver adequate road conditions for citizens. There have been several attempts at creating such systems and integrating them within Pavement management systems. This paper utilizes replicable deep learning techniques to carry out hotspot analyses on urban road networks highlighting important pavement distress types and associated severities. Following this, analyses were performed illustrating how the hotspot analysis can be carried out to…

SUP R DSS: A sustainability-based decision support & system for road pavements

2019

Road pavement community members are increasingly becoming aware of the need to incorporating the principles of sustainable development into the sector. Policies are also going in this direction and as a consequence in the recent years researchers and practitioners are coming up with new materials, technologies and practices designed to reduce the negative impacts of their activities in the surroundings. Within this framework the road pavements sector is witnessing a paradigm shift towards the development of pavement technologies incorporating high-content of recycled materials, as well as best practices to decrease the overall carbon footprint. These are all promising solutions that to the …

Elementi Decorativi in Ferro.

2001

Design considerations of high RAP-content asphalt produced at reduced temperatures

2018

In many countries recycling of reclaimed asphalt pavement (RAP) for road surface layers is limited to a maximum of 10–30%. This is due to technical limitation of common asphalt plant but also to specifications that are still restrictive when it comes to increasing RAP in surface courses. The mistrust in this practice is mainly related to uncertainty in performance of these mixes as well as to existing fundamental issues with the mix design, especially when production temperatures are lowered. This paper analyses some of the factors affecting the design of warm asphalt mixtures for surface course layers containing 50% RAP, and suggests a framework to justify the common assumption of full ble…

Exchange-transfer in mixed-valence clusters with one migrating hole

1996

Abstract A new mechanism for exchange-transfer specific to hole-type mixed-valence clusters is proposed. The intermediate state in the second-order exchange-transfer process is achieved by the jump of the electron from the spin-core of the dn+1 ion into the empty orbital of the dn ion. As distinguished from the mixed-valence clusters with one delocalized electron this intermediate state is the high-spin one giving rise to a ferromagnetic contribution to the ground manifold. On the basis of angular momentum theory a general solution of the exchange-transfer problem is given for arbitrary nuclearity mixed-valence hole-type clusters with many-electron paramagnetic spin-cores. The interplay bet…

ChemInform Abstract: Spin Density Distribution in Transition Metal Complexes: Some Thoughts and Hints

2010

Abstract The spin density distribution in transition metal complexes is discussed in qualitative terms, taking into account the coexistence of spin delocalization and spin polarization mechanisms, with the help of numerical results for several complexes obtained from density functional calculations. The covalent character of the metal-ligand bonds as well as the σ- or π-characteristics of the partially filled d orbitals must be taken into account to qualitatively predict the sign of the spin density at a particular atom within a ligand. The same patterns can be applied to binuclear complexes and can be helpful in determining the ferro- or antiferromagnetic character of the exchange coupling…

J. Vidal-Beneyto (1927-2010)

2010

Discrete Dinuclear Complexes and Two‐Dimensional Architectures from Bridging Polynitrile and Bipyrimidine (bpym) Ligands: Syntheses, Structures and M…

2004

One-pot reactions in aqueous solutions of the polynitrile anion dcne− {2,2-dicyano-1-ethoxyethenolate = [(CN)2CC(O)OEt)]−] with the MII ions (M = Mn, Fe, Co, Cu) in the presence of bpym (2,2′-bipyrimidine) afford the first mixed dcne/bpym compounds [M2(bpym)(dcne)4(H2O)2] (1: M = Mn; 2: M = Co) and [M2(bpym)(dcne)4(H2O)4]·2H2O (3: M = Fe; 4: M = Cu). The new compounds have been characterized by IR spectroscopy and X-ray crystallography. Compounds 1 and 2 are isostructural, with each metal ion being located in an MN5O pseudo-octahedral environment with three N atoms coming from three dcne− ligands, two nitrogen atoms from bpym and one oxygen atom from a water molecule. The extended structure…