cis,cis-1,3,5-Tris(diphenylphosphino)cyclohexane (tdppcy). A new tripodal phosphine that forms metal complexes with adamantane-type structures. rystal structure of Ir(tdppcy)Cl3

Recent progress in homogeneous hydrogenation of carbon dioxide to methanol

The requirement of running a new generation of fuel production is inevitable due to the limitation of oil production from reservoirs. On the other hand, enhancing the CO2 concentration in the atmosphere brings global warming phenomenon and leads to catastrophic disasters such as drought and flooding. Conversion of carbon dioxide to methanol can compensate for the liquid fuel requirement and mitigate CO2 emissions to the atmosphere. In this review, we surveyed the recent works on homogeneous hydrogenation of CO2 to CH3OH and investigated the experimental results in detail. We categorized the CO2 hydrogenation works based on the environment of the reaction, including neutral, acidic, and basic conditions, and discussed the effects of solvents’ properties on the experimental results. This review provides a perspective on the previous studies in this field, which can assist the researchers in selecting the proper catalyst and solvent for homogenous hydrogenation of carbon dioxide to methanol.

Homogeneous and heterogeneous catalysts for hydrogenation of CO2 to methanol under mild conditions

This review summarizes the concepts, mechanisms, drawbacks and challenges of the state-of-the-art catalysis for CO₂ to MeOH under mild conditions. Thoughtful guidelines and principles for future research are presented and discussed.

Mechanisms and Beyond: Elucidation of Fluxional Dynamics by Exchange NMR Spectroscopy

Detailed mechanistic information is crucial to our understanding of reaction pathways and selectivity. Dynamic exchange NMR techniques, in particular 2D exchange spectroscopy (EXSY) and its modifications, provide indispensable intricate information on the mechanisms of organic and inorganic reactions and other phenomena, for example, the dynamics of interfacial processes. In this Review, key results from exchange NMR studies of small molecules over the last few decades are systemised and discussed. After a brief introduction to the theory, the key types of dynamic processes are identified and fundamental examples given of intra- and intermolecular reactions, which, in turn, could involve, or not, bond-making and bond-breaking events. Following that logic, internal molecular rotation, intramolecular stereomutation and molecular recognition will first be considered because they do not typically involve bond breaking. Then, rearrangements, substitution-type reactions, cyclisations, additions and other processes affecting chemical bonds will be discussed. Finally, interfacial molecular dynamics and unexpected combinations of different types of fluxional processes will also be highlighted. How exchange NMR spectroscopy helps to identify conformational changes, coordination and molecular recognition processes as well as quantify reaction energy barriers and extract detailed mechanistic information by using reaction rate theory in conjunction with computational techniques will be shown.

Molybdenum dinitrogen complex supported by a cyclohexane-based triphosphine ligand and dmpm

We report the first molybdenum dinitrogen complex supported by a cyclohexane-based triphosphine ligand.

Crystal structures of fac-tri-chlorido-tris-(tri-methyl-phosphane-κP)rhodium(III) monohydrate and fac-tri-chlorido-tris-(tri-methyl-phosphane-κP)rhodium(III) methanol hemisolvate: rhodium structures that are isotypic with their iridium analogs

The crystal structures of two solvates of fac-tri-chlorido-tris-(tri-methyl-phosphane-κP)rhodium(III) are reported, i.e. one with water in the crystal lattice, fac-[RhCl3(Me3P)3]·H2O, and one with methanol in the crystal lattice, fac-[RhCl3(Me3P)3]·0.5CH3OH. These rhodium compounds exhibit distorted octahedral coordination spheres at the metal and are isotypic with the analogous iridium compounds previously reported by us [Merola et al. (2013 ▶). Polyhedron, 54, 67-73]. Comparison is made between the rhodium and iridium compounds, highlighting their isostructural relationships.

A P,O,P'-tridentate mixed-donor scorpionate ligand: 6-[4,6-bis-(diphenyl-phosphino)-10H-phenoxazin-10-yl]hexan-1-ol

The title compound, C(42)H(39)NO(2)P(2), is a P,O,P'-tridentate scorpionate-type ligand and has one mol-ecule in the asymmetric unit. The angles involving the P atoms range from 100.21 (7) to 104.89 (7)°. The N-hexa-nol group was found to be disordered and was refined over two positions with final occupancies of 0.683 (3) and 0.317 (3) which affected the C-O and C-N bond lengths. The bond lengths for C-O range from 1.402 (2) to 1.415 (2) Å and for C-N from 1.410 (2) to 1.448 (3) Å for the major disorder component; the corresponding ranges for the minor disorder component are 1.429 (3)-1.408 (3) and 1.474 (3)-1.474 (4) Å.