Molecular and electronic structure of electron-transfer active main-group organometallics

Abstract

The molecular structure of the single-electron-transfer (SET) reagent 1,4-bis(triisopropylsilyl)-1,4-dihydropyrazine (1) shows a virtually planar ring system with eight conjugating tt electrons, effectively shielded N-Si bonds, and nonbonded contacts between ring and isopropyl hydrogen atoms. The compound undergoes an electrochemically reversible one-electron oxidation at a very low potential; electronic and steric stabilization as well as an apparently small geometry change on oxidation

1,4-Dioxobenzene compounds of aluminium

“…1 The absorptions may be assigned to a ligand-to ligand charge transfer from a Al-C σ to the low lying π* orbital of the pyridine. 9 The solid state structures of compounds 2-4 have been determined by X-ray crystallography and are shown in Fig. 3-5, respectively; selected bond lengths and angles are given in Table 1.…”

Theoretical Prediction of the Heats of Formation, Densities and Relative Sensitivities, and/or Synthetic Approaches Toward the Synthesis of High Energy Dense Materials (HEDMs): 3,5-Dinitro-1,3,5-Oxadiazinane, Bis-Adjacent RDX, Bis-Adjacent HMX, 4,4',6,6'-Tetranitro-1,1'-Bis(N-oxide)-5,5',6,6'-4H,4'H-5,5'-Bisimidazo Oxadiazole, and the Open-Cage Derivative of CL-20

“…If nitrolysis occurs at the methylene carbons of the bridgehead, then the product that forms would be bis-adjacent RDX (2). On the other hand, if nitrolysis occurs preferentially at the ethylene position of the ring fusion, then the product would be the 12-membered macrocycle dodecagen (13). This latter molecule has been described theoretically by McQuaid as having higher performance than HMX, with a crystalline density of 1.93 cm 3 , a detonation velocity of 9230 m/s, and a detonation pressure of 37.0 GPa.…”

“…Disilyl-1,4-dihydropyrazine (18) can be prepared from the known dissolving metal reduction route from commercially available pyrazine. 13 Osmium-catalyzed dihydroxylation of the diene via the Upjohn procedure would furnish tetraol 19 in the required syn-configuration, which could be converted to tetra-mesylate 20. Reaction of this mesylate with methylene bisacetamide, followed by global nitration would yield 5; the open-chain version of CL-20.…”

Synthesis and reactivity of a 1,4-dihydropyrazine derivative

“…The oxidation potential described for N-ethyl-1,4dihydropyrazine is K0.67 V versus SCE. 11 Thus, the high potentials for oxidation of compound 2 can be assigned to the electron-withdrawing effect of the substituents which makes the loss of electrons more difficult. A potential sweep from 0 to K2.8 V showed a reduction peak at K2.14 V versus SCE (Fig.…”