Can boron form coordination complexes with diffuse electrons? Evidence for linked solvated electron precursors

Density functional theory and ab initio multi-reference calculations are performed to examine the stability and electronic structure of boron complexes that host diffuse electrons in their periphery. Such complexes (solvated electron precursors or SEPs) have been experimentally identified and studied theoretically for several s- and d-block metals. For the first time, we demonstrate that a p-block metalloid element can form a stable SEP when appropriate ligands are chosen. We show that three ammonia and one methyl ligands can displace two of the three boron valence electrons to a peripheral 1s-type orbital. The shell model for these outer electrons is identical to previous SEP systems (1s, 1p, 1d, 2s). Further, we preformed the first examination of a molecular system consisting of two SEPs bridged by a hydrocarbon chain. The electronic structure of these dimers is very similar to that of traditional diatomic molecules forming bonding and anti-bonding σ and π orbitals. Their ground state electronic structure resembles that of two He atoms, and our results indicate that the excitation energies are nearly independent of the chain length for four carbon atoms or longer. These findings pave the way for the development of novel materials similar to expanded metals and electrides.

Simultaneous CO2 capture and functionalization: solvated electron precursors as novel catalysts

Metal complexes with diffuse solvated electrons are proposed as alternative catalysts for the simultaneous CO2 capture and utilization. Quantum chemical calculations were used to study the reaction of CO2 with...

Catalytic Role of Solvated Electron in the Spontaneous Degradation of Insensitive Munition Compounds : Computational Chemistry Investigation

The DNAN (2,4-dinitroanisole), NTO (3-nitro-1,2,4-triazol-5-one), and NQ (nitroguanidine) are important insensitive energetic materials used in military applications. They may find their way to the environment during manufacturing, transportation, storage, training, and disposal. A detailed investigation of possible mechanisms for self-degradation of radical-anions formed by addition of solvated electron to DNAN, NTO, and NQ species was performed by computational study using the PCM(Pauling)/M06-2X/6-311++G(d,p) approach. Obtained results suggest that only NQ radical-anion is able for self-degradation by elimination of nitrite anion. Formation of urea radical on the earlier stage of the NQ radical-anion degradation was also predicted.

Superatomic Nature of Metal Encapsulated Dodecahedrane: The Case of M@C20H20 (M = Li, Na, Mg+)

The idea of designing unprecedented materials made of superatomic building blocks, motivated the present study on endohedral M@C20H20 (M = Li, Na, Mg+) species. Ground and excited electronic structures of M@C20H20 (M = Li, Na, Mg+) were analyzed by means of high-level quantum calculations. In their ground states, one electron occupies a defuse superatomic s-orbital that lies around the C20H20 cage. These entities populate higher angular momentum p-, d-, f-, g-superatomic orbitals in their low-lying electronic states. The proposed superatomic Aufbau shell model for Li@C20H20 and Na@C20H20 is 1s, 1p, 1d, 2s, 1f, 2p, 2d, 1g, 2f slightly different from that of Mg@C20H20+ which is 1s, 1p, 1d, 2s, 1f, 2p, 2d, 1g, 3s, 2f, 2g, 3p. These introduced superatomic orbital series resemble the Aufbau principle of solvated electron precursors.

Trap Seeker and Digger: The Dual Identity of the Solvated Electron in Methanol

<div> <div> <div> <p>The structure of the solvated electron in methanol is less studied but more complicated than the one of the hydrated electron. In this condensed-phase first principles molecular dynamics study we reveal the nature of the recently discovered shallow and deep trap states of the excess electron and suggest a more complex picture including four bound cavity states classified by the number of the hydroxy-groups coordinated to the electron, their binding energy gradually increasing with the OH-coordination. The initial shallow bound states are formed via a transient diffusion mechanism, in a trap-seeking fashion, whereas, deeper bound states are formed via a slower methanol molecules reorientation. Despite apparent similarity of the absorption spectrum of the solvated electron in methanol to that in water, the origin of the absorption maximum is drastically different. The previously assumed model of hydrogenic transitions (s-p etc.) as is the case in water does not hold for methanol. Instead, the main bands arise due to the charge-transfer states, promoting the excess electron to the nearby cavity, naturally abundant in this solvent. We propose an alternative simple model to describe electronic states of the solvated electron in methanol: the double square well.</p> </div> </div> </div>

Trap Seeker and Digger: The Dual Identity of the Solvated Electron in Methanol

<div> <div> <div> <p>The structure of the solvated electron in methanol is less studied but more complicated than the one of the hydrated electron. In this condensed-phase first principles molecular dynamics study we reveal the nature of the recently discovered shallow and deep trap states of the excess electron and suggest a more complex picture including four bound cavity states classified by the number of the hydroxy-groups coordinated to the electron, their binding energy gradually increasing with the OH-coordination. The initial shallow bound states are formed via a transient diffusion mechanism, in a trap-seeking fashion, whereas, deeper bound states are formed via a slower methanol molecules reorientation. Despite apparent similarity of the absorption spectrum of the solvated electron in methanol to that in water, the origin of the absorption maximum is drastically different. The previously assumed model of hydrogenic transitions (s-p etc.) as is the case in water does not hold for methanol. Instead, the main bands arise due to the charge-transfer states, promoting the excess electron to the nearby cavity, naturally abundant in this solvent. We propose an alternative simple model to describe electronic states of the solvated electron in methanol: the double square well.</p> </div> </div> </div>