1,1-Dinitriles malonitrile

Dicyanomethane or Malononitrile (called Malonsaure-dinitril, Malonitril or Methylen-cyanid in Ger), NC.CH2.CN mw 66.06, N 42.41% col crysts, mp 31.6-32.4°, bp 108-09° at 17mm press, cryst d 1.191 at 20°, liq d 1.0494 at 35°, nfi 1.4139 at 34.2° prepd by esterification of cyanoacecic acid, and treatment of the ester with NH3 which leads to cyanoacetamide which, on reaction with phosphorous oxychloride or pentachloride, gives Dicyanomethane (Ref 1)... 

At 130°C or at ambient temperature and in the presence of bases, malonitrile gives rise to a very violent polymerisation. The stability of this dinitrile in the molten state (mp 32°C) decreases with the temperature rise and its fall in purity. It was assumed that decomposition never occurs below 100 C. However, when this compound was heated to 70-80°C for two months, this caused a very violent detonation. 

Complexes of MXs with dinitriles CN(CH2) CN ( = 1-4) have been prepared.Both [MXsL] and [MXsL ] have been isolated in the case of malonitrile, succinonitrile and glutaronitrile, whereas only [(MXs)2L] formed with adiponitrile. In the case of succinonitrile and glutaronitrile, trans conformers have been assigned to the 2 1 adducts, while a gauche conformation was assumed in 1 1 complexes the more stable gauche-trans-gauche conformation for adiponitrile was proposed in its 1 2 adducts. 

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