Heats of combustion and heats of formation of 3,4-dicyanofuroxan, 3,4-dicyanofurazan, and sesquimer of 3,4-dicyanofuroxan

Lupton, Elmer C.; Hess, Guillermo Nudelman

doi:10.1021/je60065a011

Cited by 11 publications

(3 citation statements)

References 2 publications

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“…Another known synthesis of dicyanofuroxan, possibly involving the intermediacy of NCCNO, is based on the nitric acid oxidation of cyanoacetic acid. 60,61 The TR2 and TR3 trimer structures have been suggested as by-products of this route, 62 and more recently 63 these trimers were isolated (characterised by X-ray crystallography) from the reaction mixture supporting, indirectly, NCCNO formation, and in agreement with the calculations (Fig. 8).…”

Section: Polymerisation Of Nccnosupporting

confidence: 77%

Dimerisation of nitrile oxides: a quantum-chemical study

Pasinszki

Hajgató

Havasi

et al. 2009

Phys. Chem. Chem. Phys.

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The [3 + 2] and [3 + 3] cyclodimerisation processes of small nitrile oxides, XCNO (X = F, Cl, Br, CN, CH(3)) are investigated by ab initio coupled cluster theory at the CCSD, CCSD(T) and MR-AQCC levels for the first time. The favoured dimerisation process is a multi-step reaction to furoxans (1,2,5-oxadiazole-2-oxides) involving dinitrosoalkene-like intermediates with diradical character. The rate determining step for all but the F-species is the first, corresponding to the C-C bond formation. The kinetic energy barrier depends on the nature of the substituent X, generally increasing with decreasing electronegativity and increasing pi-donor ability of the substituent: F (DeltaG(298) = 0 kJ mol(-1)) < Cl (72) < Br (90) < CH(3) (104) < CN (114) (MR-AQCC(2,2)//UB3LYP/cc-pVTZ). Following initial C-C bond formation, three possible dinitrosoethylene diradical pathways are explored. Two of them are new, and one of them is a low-energy three-step path with implications for cycloreversion, tautomerism and detection of dinitrosoethylene intermediates. Alternative one-step, concerted [3 + 2] and [3 + 3] cyclodimerisation processes leading to 1,2,4-oxadiazole-4-oxides and 1,4,2,5-dioxadiazines have kinetic energy barriers around 100-240 kJ mol(-1) (CCSD//B3LYP), some 1.6 to 2.5 times higher than those leading to furoxans, supporting the experimental observations of furoxan formation as nitrile oxide loss channels during storage, trapping/re-vaporisation and reactions of nitrile oxides. Potential polymerisation initiation processes for NCCNO, involving the 1,2-dipolar NC substituent are also explored.

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Section: Polymerisation Of Nccnosupporting

confidence: 77%

Dimerisation of nitrile oxides: a quantum-chemical study

Pasinszki

Hajgató

Havasi

et al. 2009

Phys. Chem. Chem. Phys.

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“…Consideration of the possible structure of the transition state for the tautomerization of 4-nitrobenzofurazan-1-oxide shows that the anti dinitroso configuration would not be permitted, so that steric hindrance in the transition state would increase considerably the activation energy in this case. (33) 107.323.8 (33) 254.224.0 21.221.0 (34) 10.821.9 (34) 238.822.1 465.720.8 (cr) (35) 456.125.4 (cr) (35) 240210 a a Assuming D g cr H°m for this furazan and furoxan are equal.…”

Section: (4)mentioning

confidence: 96%

Enthalpies of combustion of 5-methoxybenzofurazan, 5-methoxybenzofurazan-1-oxide, 5-methylbenzofurazan-1-oxide, 5-chlorobenzofurazan-1-oxide and 4-nitro-benzofurazan-1-oxide: the dissociation enthalpies of the N–O bonds

Acree

Bott

Tucker

et al. 1996

The Journal of Chemical Thermodynamics

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“…The solvent was removed on a rotary evaporator, and the residue was purified by sublimation to provide 4.92 g (86.4%) of dimeric nitroso compound 9 as a khaki solid: mp 79-80 °C; UV-VIS (CCl 4 , l max /nm): 750. IR (KBr, n/cm 3,4-Dicyanofuroxan 4 is an important building block in organic synthesis, 4,[9][10][11][12][13][14][15] and exhibits interesting biological and pharmacological properties, for instance, as a vasodilator. 16 It can be used as an ingredient of explosives 17 and rocket propellants.…”

mentioning

confidence: 99%