Rare-Earth Metal Boroxide with Formal Triple Metal-Oxygen Orbital Interaction:Synthesis from B(C_(6)F_(5))_(3)·H_(2)O and Radical-Anion Ligated Rare-Earth Metal Amides

Rare-earth metal boroxides are not only rare and of great synthetic challenge but also important theoretically due to their unrevealed bonding characteristics.In this paper,we report the synthesis,characterization,and bonding characteristics of the 4f-block metal boroxide complexes ^(Mes)DAD_(2)LuOB(C_(6)F_(5))X(4-Lu,X=C_(6)F_(5);5-Lu,X=NC_(13)H_(10))with two chelating radical-anionic 1,4-diazabutadiene(DAD)ligands.The synthesis of 4-Lu or 5-Lu involved three steps,during which the radical-anionic DAD ligands could be kept stable:(1)the reaction of LuCl_(3),^(Mes)DAD,and potassium graphite(KC8)afforded the diradical rare-earth metal chloride ^(Mes)DAD_(2)LuCl·tetrahydrofuran(THF)(1-Lu);(2)the salt metathesis of 1-Lu with two alkali metal amides gave lutetium bis(diazabutadiene)amides 2-Lu or 3-Lu,respectively;and(3)2-Lu or 3-Lu reacted with B(C_(6)F_(5))_(3)·H_(2)O,resulting in the formation of rare-earth metal boroxides 4-Lu or 5-Lu.The radical-anionic nature of DAD ligands in these complexes were proven by their bond lengths and coordination modes in single-crystal structures.DFT calculations clearly show the bonding of 4-Lu can be divided into three major types of Lu-O orbital interactions,which can be categorized asσ-donation,π-donation,and d-π-conjugation.The triple Lu-O orbital interactions cooperatively make a Lu-O single bond and contribute to the linear Lu-O-B structure.

Advances in electrochemical transformation of N_(2)using molecular catalysts

The conversion of N_(2)to NH_(3)holds great importance due to the essential role of NH_(3)in fertilizer production,energy storage and the synthesis of key industrial chemicals.Development of novel methods for N_(2)transformation is a worthwhile goal and researchers have turned their attention to electrochemical N_(2)reduction as a potentially sustainable solution.The development of molecular electrocatalysts has gained considerable momentum over the last decades,and this review focuses on the advances and challenges in the field of molecular electrochemical nitrogen fixation and aims to inspire further research into the realm of nitrogen fixation chemistry from an electrochemical perspective.

Light-Driven Dinitrogen Activation with Transition Metal Complexes:Mechanisms and Applications

Comprehensive Summary,The Haber-Bosch process,which is used for ammonia(NH3)synthesis,requires vast amounts of energy,accounting for approximately 1%—2%of the world's annual energy consumption.Therefore,researchers in both industry and academia are interested in developing sustainable and environmentally friendly methods for synthesizing nitrogenous compounds at ambient conditions using renewable energy sources such as visible light.While several examples of thermal activation of dinitrogen molecules have been demonstrated using various transition metals and ligand frameworks,the use of light to weaken or split the strong N—N bond has been less explored.This article presents an overview of molecular complexes capable of dinitrogen photocleavage and provides mechanistic insights into the photoactivation process through experimental and theoretical studies.We believe this review will provide readers with an in-depth understanding of the current state-of-the-art and future research perspectives,particularly in the use of visible light for dinitrogen activation and transformation.

Synthesis and structural analysis of titanium-μ-dinitrogen complex supported by di-anionic guanidinate ligands

The synthesis,characterization,and theoretical studies of titanium-μ-N_(2) complexes with di-anionic guanidinate ligands were reported as the first example of its kind.Thus,with(Me_(3)Si)_(2)N-guanidinate ligands,the mono-anionic guanidinate-supported titanium-μ-N2complex 1 was obtained.Then,reduction of 1 with potassium afforded the di-anionic guanidinate-supported titanium-μ-N_(2) complex 2 via cleavage of one N–Si bond of the(Me3Si)2N substituents in 1,changing the guanidinate ligands automatically from mono-anionic to di-anionic and remarkably lengthening the bond length of theμ-N_(2).Characteristic studies and DFT calculations were performed to reveal that the di-anionic guanidinate ligands stabilized the geometry of 2 and increased the charge density on the bridging dinitrogen.

One-Electron Reduction of Constrained and Unsymmetric Diiron Dinitrogen Complexes

Iron sites in both nitrogenase enzymes and chemical catalysts for N2 fixation are typically at constrained distances and angles.Herein,we report a one-electron reduction reaction realized by constrained diiron dinitrogen cores.Using the semicircular bis(β-diketiminate)ligand,a series of diiron dinitrogen complexes were synthesized,in which the N2 groups were allowed to bind with Fe-Ct_(N2)-Fe angles ranging from 154°to 158°(Ct_(N2)=centroid of N2).One-electron reduction of complex 2a[LFe(μ-N_(2))Fe(Et2O)]gave dimer product 3a[LFe(μ-N_(2))FeK]_(2)(μ-N_(2))or monomer 3b[LFe(μ-N_(2))Fe(DMAP)K].Based on superconducting quantum interference device measurements and density functional theory calculations,2a,3a,and 3b exhibited ground spin states of S=3,S=5,and S=5/2,respectively.In addition,complex 3 underwent N_(2)derivatization via a silylation pathway followed by an acidic cleavage to yield N_(2)H_(4)as the product.

Isolation and Characterization of Four Phosphorus Cluster Anions P7^3-,P14^4-,P16^2- and P26^4- from the Nucleophilic Functionalization of white Phosphorus with 1,4-Dilithio-1,3-butadienes

Summary of main observation and conclusion Studies on the aggregation degrees of negatively charged phosphides derived from the nucleophilic P4 functionalization could help understand the pathway of phosphorus atoms degradation or aggregation.In this report,we have isolated and characterized four phosphorus cluster anions (P7^3-,P14^4-,P16^2-,and P26^4-)from the nucleophilic functionalization of P4 with 1,4-dilithio-1,3-butadienes.These phosphorus clusters could be rationalized as the P-atom-containing products besides the main phospholyl lithium.Their structural features and 31p NMR behaviors are discussed based on single crystal X-ray diffraction analysis and 31P{1H}COSY NMR analysis.

Dinitrogen Functionalization Affording Structurally Well-Defined Cobalt Diazenido Complexes

Cobalt-bis(dinitrogen)complexes[LCo(N_(2))_(2)]−(3,4)with simple and commercially available bidentate phosphine ligands(L:Cy_(2)PCH_(2)CH_(2)PCy_(2))were synthesized and structurally characterized.Further N2 functionalization by treating the complex 3b with i Pr_(3)SiCl afforded the first structurally characterized cobalt diazenido complex 5.These complexes 3–5 were found to be effective catalysts for the transformation of N2 into N(SiMe_(3))_(3).The electronic structure of the cobalt diazenido complex 5 is supported by quantum computational calculations based on stateof-the-art energy decomposition analysis(EDA)in conjunction with the natural orbitals for chemical valence(NOCV)method.

Dinitrogen Activation of Cyclopentadienyl-Phosphine–Iron Complexes of Three Different Valences

A series of structurally well-defined iron-dinitrogen complexes(LFe-N2)bearing cyclopentadienylphosphine ligands(L)were synthesized and analyzed by single-crystal X-ray structural analysis,IR/Raman spectra,magnetometry,Mössbauer spectroscopy,and elemental analysis.The conversion relationship and the change of the spin states among the iron complexes with different valences were studied in detail.