Redox-Neutral Transformations of Carbon Dioxide Using Coordinatively Unsaturated Late Metal Silyl Amide Complexes.

Two-coordinate silylamido complexes of nickel and copper rapidly react with CO to selectively form a new cyanate ligand along with hexamethyldisiloxane byproducts. Mechanistic insight into these reactions was obtained from the synthesis of proposed intermediates, several silyl- and phenyl- substituted amido analogues, and their subsequent reactivity with CO. These studies suggest that a unique intramolecular double silyl transfer step facilitates CO deoxygenation, which likely contributes to the rapid rates of reaction.

Facile Addition of B-H and B-B Bonds to an Iron(IV) Nitride Complex.

The nitride ligand in the iron(IV) complex PhB(PrIm)Fe≡N reacts with boron hydrides to afford PhB(PrIm)FeN()H ( = 9-BBN (), Bpin ()) and with (Bpin) to afford PhB(PrIm)FeN(Bpin) (). The iron(II) borylamido products have all been structurally and spectroscopically characterized, demonstrating facile insertion into B-H and B-B bonds by PhB(PrIm)Fe≡N. Density functional theory (DFT) calculations reveal that the quintet state ( = 2) is significantly lower in energy than the singlet ( = 0) and triplet ( = 1) states for all products.

An Integrated View of Nitrogen Oxyanion Deoxygenation in Solution Chemistry and Electrospray Ion Production.

There has been an increasing interest in chemistry involving nitrogen oxyanions, largely due to the environmental hazards associated with increased concentrations of these anions leading to eutrophication and aquatic "dead zones". Herein, we report the synthesis and characterization of a suite of MNO complexes (M = Co, Zn: = 2, 3). Reductive deoxygenation of cobalt bis(nitrite) complexes with bis(boryl)pyrazine is faster for cobalt than previously reported nickel, and pendant O-bound nitrito ligand is still readily deoxygenated, despite potential implication of an isonitrosyl primary product.

Nickel-mediated N-N bond formation and NO liberation nitrogen oxyanion reduction.

The syntheses of (DIM)Ni(NO) and (DIM)Ni(NO), where DIM is a 1,4-diazadiene bidentate donor, are reported to enable testing of bis boryl reduced N-heterocycles for their ability to carry out stepwise deoxygenation of coordinated nitrate and nitrite, forming O(Bpin). Single deoxygenation of (DIM)Ni(NO) yields the tetrahedral complex (DIM)Ni(NO)(ONO), with a linear nitrosyl and κ-ONO. Further deoxygenation of (DIM)Ni(NO)(ONO) results in the formation of dimeric [(DIM)Ni(NO)], where the dimer is linked through a Ni-Ni bond.

A Redox-Active Tetrazine-Based Pincer Ligand for the Reduction of N-Oxyanions Using a Redox-Inert Metal.

The reaction chemistry of the bis-tetrazinyl pyridine ligand (btzp) towards nitrogen oxyanions coordinated to zinc is studied in order to explore the reduction of the NO substrates with a redox-active ligand in the absence of redox activity at the metal. Following syntheses and characterization of (btzp)ZnX for X=Cl, NO and NO , featuring O-Zn linkage of both nitrogen oxyanions, it is shown that a silylating agent selectively delivers silyl substituents to tetrazine nitrogens, without reductive deoxygenation of NO . A new synthesis of the highly hydrogenated H btzp, containing two dihydrotetrazine reductants is described as is the synthesis and characterization of (H btzp)ZnX for X=Cl and NO , both of which show considerable hydrogen bonding potential of the dihydrotetrazine ring NH groups.