7,7,8,8-Tetracyanoquinodimethane

The Tetracyanoquinodimethane, with the CAS registry number 1518-16-7 and EINECS registry number 216-174-8, has the systematic name of 2,2'-cyclohexa-2,5-diene-1,4-diylidenedipropanedinitrile. And the molecular formula of this chemical is C₁₂H₄N₄. It is an kind of orange to green crystalline powder, and belongs to the following product categories: Aromatic Nitriles; Acceptors (Charge Transfer Complexes); Charge Transfer Complexes for Organic Metals; Functional Materials; TCNQ Derivatives. In addition, it is an electron-acceptor that is used to prepare charge transfer salts, which are of interest in the area of molecular electronics.

The physical properties of Tetracyanoquinodimethane are as following: (1)# of Rule of 5 Violations: 0; (2)ACD/BCF (pH 5.5): 1; (3)ACD/BCF (pH 7.4): 1; (4)ACD/KOC (pH 5.5): 14.927; (5)ACD/KOC (pH 7.4): 14.927; (6)#H bond acceptors: 4; (7)#H bond donors: 0; (8)#Freely Rotating Bonds: 0; (9)Polar Surface Area: 95.16 Å²; (10)Index of Refraction: 1.63; (11)Molar Refractivity: 53.488 cm³; (12)Molar Volume: 150.343 cm³; (13)Polarizability: 21.204×10^-24cm³; (14)Surface Tension: 83.235 dyne/cm; (15)Density: 1.358 g/cm³; (16)Flash Point: 99.674 °C; (17)Enthalpy of Vaporization: 49.212 kJ/mol; (18)Boiling Point: 254.677 °C at 760 mmHg; (19)Vapour Pressure: 0.017 mmHg at 25°C.

Preparation of Tetracyanoquinodimethane: It can be prepared by the condensation of 1,4-cyclohexanedione with malononitrile, followed by dehydrogenation of the resulting diene with bromine:
C₆H₈O₂ + 2 CH₂(CN)₂ → C₆H₈(C(CN)₂)₂ + 2 H₂O
C₆H₈(C(CN)₂)₂ + 2 Br₂ → C₆H₄(C(CN)₂)₂ + 4 HBr

You should be cautious while dealing with this chemical. It is harmful by inhalation, in contact with skin and if swallowed. Therefore, you had better take the following instructions: Wear suitable protective clothing, gloves and eye/face protection, and in case of contacting with eyes, rinse immediately with plenty of water and seek medical advice; Avoid contact with skin and eyes; Do not breathe dust.

You can still convert the following datas into molecular structure:
(1)SMILES: c1cc(=C(C#N)C#N)ccc1=C(C#N)C#N
(2)InChI: InChI=1/C12H4N4/c13-5-11(6-14)9-1-2-10(4-3-9)12(7-15)8-16/h1-4H
(3)InChIKey: PCCVSPMFGIFTHU-UHFFFAOYAI

The toxicity data is as follows:

Organism	Test Type	Route	Reported Dose (Normalized Dose)	Effect	Source
mouse	LD50	intravenous	56mg/kg (56mg/kg)		U.S. Army Armament Research & Development Command, Chemical Systems Laboratory, NIOSH Exchange Chemicals. Vol. NX#00796,