74-90-8 Usage
Chemical Description
Hydrogen cyanide, potassium cyanide, and sodium diethyl cyanomethylphosphonate are all reagents used in the synthesis of these compounds.
Description
Hydrogen cyanide, also known as hydrocyanic acid (HCN), is a highly corrosive and toxic chemical compound. It is a dangerous fire and explosion risk due to its wide flammable range of 6%-41% in air. Hydrogen cyanide has a boiling point of 79°F (26°C), a flash point of 0°F, and an ignition temperature of 1004°F (540°C). It is toxic through inhalation, ingestion, and skin absorption, with a threshold limit value (TLV) of 10 ppm in air.
Uses
Used in Chemical Production:
Hydrogen cyanide is used as a key intermediate in the manufacture of various chemical products and intermediates for organic syntheses. It is used in the production of acrylonitrile, acrylates, cyanide salts, dyes, rodenticides, and other pesticides.
Used in Fumigation:
Hydrogen cyanide is used as a horticultural fumigant and sometimes applied as a disinfectant in gas form or cellulosic disks impregnated with HCN.
Used in Ore Processing and Metal Treating:
In the mining industry, cyanides are widely used for ore processing and metal treating.
Used in Manufacturing Synthetic Fibers, Plastics, and Dyes:
Hydrogen cyanide is used as an intermediate in the production of synthetic fibers, plastics, and dyes.
Used in Producing Methyl Methacrylate, Cyanuric Chloride, and Triazines:
Hydrogen cyanide is used in the production of methyl methacrylate, cyanuric chloride, and triazines.
Used in Chelate Production:
Hydrogen cyanide is used in the production of chelates such as ethylenediaminetetraacetic acid (EDTA).
Used in Electroplating:
Hydrogen cyanide is used in the electroplating industry.
Sources:
Hydrogen cyanide occurs naturally in beet sugar residues, coke oven gas, and the roots of certain plants such as sorghum, cassava, and peach tree roots. It is also found in trace amounts in apricot seeds and tobacco smoke.
History
Hydrogen cyanide in pure form was prepared first in 1815 by Gay-Lussac.Earlier, in 1782, Scheel prepared this compound in dilute solution. The mostimportant application of hydrogen cyanide is to produce methyl methacrylatefor methacrylate resins and plastics. Other products made from hydrogencyanide include potassium cyanide, sodium cyanide, adiponitrile, methionine,cyanuric chloride, cyanogen, nitrilotriacetic acid, and several triazine pesti-cides. The compound also is used in small amounts for extermination ofrodents.
Production Methods
Hydrogen cyanide can be prepared from a mixture of NH3, methane, and air by partial combustion in the presence of a platinum catalyst: HN3 + CH4 + 1.5 O2 +6 N2 → HCN +3 H2O + 6N2 The process is carried out at about 900–1,000 °C; yield ranges from 55–60%. In another process, methane (contained in natural gas) is reacted with NH3 over a platinum catalyst at from 1,200–1,300 °C, the reaction requiring considerable heat input. In still another process, a mixture of methane and propane is reacted with NH3 : C3H8 + 3NH3 → 3HCN + 7H2; or CH4 + NH3 → HCN + 3H2. An electrically heated fluidized bed reactor is used. Reaction temperature is approximately 1,510 °C.
Production Methods
Hydrogen cyanide has been manufactured from sodium
cyanide and mineral acid and from formamide by catalytic
dehydration. Two synthesis processes account for most of the
hydrogen cyanide produced. The dominant commercial process
for direct production of hydrogen cyanide is based on
classic technology involving the reaction of ammonia,
methane (natural gas), and air over a platinum catalyst; it
is called the Andrussow process. The second process, which involves the reaction of ammonia and methane, is called the
Blaus€aure–Methan–Ammoniak (BMA) process;
it was developed by Degussa in Germany. Hydrogen cyanide
is also obtained as a by-product in the manufacture of
acrylonitrile by the ammoxidation of propylene (Sohio
process).
Preparation
Hydrogen cyanide is generally produced in industrial quantities by hightemperature catalytic reaction between ammonia, methane, and air (theAndrussow process). The stoichiometry of the process is:
2CH4 + 2NH3 + 3O2 → HCN + 3H2O ΔHrxn = 230.4 kcal
The above reaction is endothermic requiring a temperature of 1,100°C and acatalyst such as platinum or rhodium. Other hydrocarbons may be usedinstead of methane.
The compound may be made by several other methods, which include:1. Heating methanol and ammonia in the absence of air at elevated temperatures (600 to 950°C) using a catalyst:
CH3OH + NH3 → HCN + H2O + H2
2. Thermal decomposition of formamide at elevated temperatures and reduced pressure:
HCONH2 → HCN + H2O
3. Heating acetonitrile and ammonia at 1,100 to 1,300°C:
CH3CN + NH3 → 2HCN +2H2
4. Reaction of sodium cyanide or potassium cyanide or potassium ferrocyanide with a mineral acid:
NaCN + HCl → HCN + NaCl
K4Fe(CN)6 + 6HCl → 6HCN + 4KCl + FeCl2
Reactions
Hydrogen cyanide reacts with hydrogen at 140 °C in the presence of a catalyst, e.g., platinum black, to form methyl amine CH3NH2. When burned in air, it produces a pale violet flame; when heated with dilute sulfuric acid, it forms formamide HCONH2 and ammonium formate HCOONH4; when exposed to sunlight with chlorine it forms cyanogen chloride CNCl, plus hydrogen chloride. An important reaction of hydrogen cyanide is that with aldehydes or ketones, whereby cyanhydrins are formed, e.g., acetaldehyde cyanhydrin CH3CHOH·CH, and the resulting cyanhydrins are readily converted into alpha-hydroxy acids, e.g., alphahydroxypropionic acid CH3·CHOH·COOH.
Reactivity Profile
This particular record contains hydrogen cyanide dissolved in water. Hydrogen cyanide is a very volatile liquid or colorless gas smelling of bitter almonds, b.p. 26° C. A deadly human poison by all routes. The gas (hydrogen cyanide) forms explosive mixtures with air, HYDROGEN CYANIDE reacts violently with acetaldehyde. HYDROGEN CYANIDE is a severe explosion hazard when heated or exposed to oxidizers. HYDROGEN CYANIDE may polymerize explosively at elevated temperature (50-60° C) or in the presence of traces of alkali [Wohler, L. et al., Chem. Ztg., 1926, 50, p. 761, 781]. In the absence of a stabilizer (e.g., phosphoric acid) HYDROGEN CYANIDE may undergo explosively rapid spontaneous (autocatalytic) polymerization leading to a fire. The reaction is autocatalytic because of ammonia formation. The anhydrous acid should be stabilized by the addition of acid. [Bond, J., Loss Prev. Bull., 1991, 101, p.3]. During the preparation of imidoester hydrochlorides, hydrogen chloride was rapidly passed over alcoholic hydrogen cyanide. An explosion ensued, even with cooling of the process, [J. Org. Chem., 1955, 20, 1573].
Hazard
Flammable, dangerous fire risk, explosive
limits in air 6–41%. Toxic by ingestion, inhalation,
and skin absorption. TLV: ceiling 4.7 ppm.
Health Hazard
TOXIC; inhalation, ingestion or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.
Health Hazard
Exposures to hydrogen cyanide cause adverse health effects to animals and humans.
Hydrogen cyanide is readily absorbed from the lungs and the symptoms of poisoning
begin within seconds to minutes. The symptoms of toxicity and poisoning include, but
are not restricted to, asphyxia, lassitude or weakness, exhaustion, headache, confusion,
nausea, vomiting, increased rate and depth of respiration, or respiration slow and gasp-
ing, thyroid and blood changes. Inhalation of hydrogen cyanide causes headache, dizzi-
ness, confusion, nausea, shortness of breath, convulsions, vomiting, weakness, anxiety,
irregular heart beat, tightness in the chest, and unconsciousness, and these effects may be
delayed. The target organs of induced toxicity and poisoning include the CNS, cardiovas-
cular system, thyroid, and blood.
Health Hazard
HCN is particularly dangerous because of its toxic and asphyxiating effects on all life
requiring oxygen to survive. HCN combines with the enzymes in tissue associated with
cellular oxidation. The signs and symptoms of HCN poisoning are non-specifi c and very
rapid. The symptoms include excitement, dizziness, nausea, vomiting, headache, weakness, drowsiness, gasping, thyroid, blood changes, confusion, fainting, tetanic spasm,
lockjaw, convulsions, hallucinations, loss of consciousness, coma, and death. When oxygen becomes unavailable to the tissues, it leads to asphyxia and causes death. Children are
more vulnerable to HCN exposure. HCN is readily absorbed from the lungs; symptoms of
poisoning begin within seconds to minutes. Inhalation of HCN results in the rapid onset
of poisoning, producing almost immediate collapse, respiratory arrest, and death within
minutes (Table 1)
Health Hazard
The acute toxicity of hydrogen cyanide is high, and exposure by inhalation,
ingestion, or eye or skin contact can be rapidly fatal. Symptoms observed at low
levels of exposure (e.g., inhalation of 18 to 36 ppm for several hours) include
weakness, headache, confusion, nausea, and vomiting. Inhalation of 270 ppm can
cause immediate death, and 100 to 200 ppm can be fatal in 30 to 60 min. Aqueous
solutions of HCN are readily absorbed through the skin and eyes, and absorption of
50 mg can be fatal. In humans, ingestion of 50 to 100 mg of HCN can be fatal.
Because there is wide variation in the ability of different individuals to detect the
odor of HCN, this substance is regarded as having poor warning properties.
Effects of chronic exposure to hydrogen cyanide are nonspecific and rare
Health Hazard
Hydrogen cyanide is a dangerous acute poison by all toxic routes. Acute inhalation may cause death in seconds. Lethal effects due to inhalation of its vapor depend on its concentration in air and time of exposure. Inhalation of 270 ppm HCN in air can be fatal to humans instantly, while 135 ppm can cause death after 30 minutes (Patty 1963; ACGIH 1986). Exposure to high concentration can cause asphyxia and injure the central nervous system, cardiovascular system, liver, and kidney. HCN is extremely toxic via ingestion, skin absorption, and ocular routes. Swallowing 50 mg can be fatal to humans. The symptoms of HCN poisoning at lethal dosage are labored breathing, shortness of breath, paralysis, unconsciousness, convulsions, and respiratory failure. At lower concentrations toxic effects are headache, nausea, and vomiting. LD50 value, intravenous (mice): 0.99 mg/kg LD50 value, oral (mice): 3.70 mg/kg Investigating the relationship between pH (in the range 6.8–9.3) and the acute toxicity of HCN on fathead minnow, Broderius et al. (1977) observed that similar to H2S, the toxicity of HCN increased at an elevated pH value. This was attributed to certain chemical changes occurring at the gill surface and possible penetration of the gill by both molecular and anionic forms. In an acute lethal toxicity study on the influence of exposure route, Ballantyne (1983a) observed that the blood cyanide concentrations varied with the route. Concentrations in certain specific tissues varied markedly with exposure route. The blood cyanide concentration was lowest by inhalation and skin penetration. For a given exposure route, the cyanide level in blood were similar for different species. Among the most toxic cyanides, HCN was more toxic than NaCN or KCN by intramuscular and transocular routes. Blank et al. (1983) carried out inhalation toxicity studies of hydrogen cyanide on Sprague-Dawley rats. Exposure at 68 ppm HCN in air 6 hours per day for three consecutive days showed symptoms of hypoactivity, breathing difficulties, signs of hypoxia, convulsions, and chromorhinorrhea. Death resulted in three of the five male rats after 1 day of exposure, caused by cyanosis of the extremities, moderate to severe hemorrhage of the lung, and pulmonary edema. All female rats survived. In a 4-week study, no mortality was observed at concentrations up to 58 ppm HCN. A brief exposure to 125 ppm HCN for 15 minutes, however, was fatal to 20% of the test animals. Increased urine thiocyanate levels were observed in test animals However, no adverse effects were observed in rats exposed at 29 ppm HCN 6 hour’s weekday in 4-week studies. Alarie and Esposito (1988) proposed a blood cyanide concentration of 1 mg/L as the fatal threshold value for HCN poisoning by inhalation. A cyanide concentration of 1.2 mg/L was measured in test animals exposed to nylon carpet smoke. The combined toxicities of fire-effluent gases CO and HCN was found to be additive (Levin et al. 1988). The study indicated that the sublethal concentrations of the individual gases became lethal when combined. Furthermore, the presence of CO2 combined with decreasing oxygen concentration enhanced the toxicity of the CO–HCN mixture (Levin et al. 1987). HCN and nitric oxide hastened the incapacitation in rats produced by carbon monoxide. Such incapacitation occurred at a carbonyl hemoglobin concentration of 42.2–49%; while for CO alone 50–55% carbonyl hemoglobin manifested the same effect (Conditet al. 1978).
Fire Hazard
Hydrogen cyanide is a highly flammable liquid. Liquid HCN contains a stabilizer
(usually phosphoric acid), and old samples may explode if the acid stabilizer is not
maintained at a sufficient concentration.
Fire Hazard
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.
Flammability and Explosibility
Hydrogen cyanide is a highly flammable liquid. Liquid HCN contains a stabilizer
(usually phosphoric acid), and old samples may explode if the acid stabilizer is not
maintained at a sufficient concentration.
storage
Hydrogen cyanide should be stored in a cool, dry, well-ventilated area in tightly sealed
containers and with the correct label. Containers of hydrogen cyanide should be protected
from physical damage and should be stored separately from amines and oxidizers, such
as perchlorates, peroxides, permanganates, chlorates, and nitrates. It should be kept sepa-
rated from strong acids, such as hydrochloric, sulfuric, and nitric acids, away from sodium
hydroxide, calcium hydroxide, sodium carbonate, water, ammonia, acetaldehyde, and
caustics.
Purification Methods
HCN is prepared from NaCN and H2SO4, and dried by passage through H2SO4 and over CaCl2, then distilled in a vacuum system and degassed at 77oK before use [Arnold & Smith J Chem Soc, Faraday Trans 2 77 861 1981]. Cylinder HCN may contain stabilisers against explosive polymerisation, together with small amounts of H3PO4, H2SO4, SO2, and water. It can be purified by distillaton over P2O5, then frozen in Pyrex bottles at Dry-ice temperature for storage. [Zeigler Org Synth Coll Vol I 314 1941, Glemser in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I pp 658-660 1963.] Liquid HCN, like liquid ammonia, evaporates very slowly since the latent heat of evaporation is high and keeps it in the liquid state because the temperature of the liquid is lowered to below its boiling point. EXTREMELY POISONOUS; all due precautions should be taken.
Incompatibilities
HCN can polymerize explosively if heated above 50 °C or in the presence of trace
amounts of alkali.
Waste Disposal
In the event of a spill, remove all ignition sources. Cleanup should be conducted
wearing appropriate chemical-resistant clothing and respiratory protection
Disposal Excess hydrogen cyanide and waste material containing this substance should be
placed in an appropriate container, clearly labeled, and handled according to your
institution's waste disposal guidelines. For more information on disposal procedures,
see Chapter 7 of this volume.
Precautions
Occupational workers should be very careful in the management of HCN since the gas in
air is explosive at concentrations over 5.6%, equivalent to 56,000 ppm and it does not provide adequate warning of hazardous concentrations. HCN at a concentration of 300 mg/m3
in air becomes fatal within about 10 min and HCN at a concentration of 3500 ppm (about
3200 mg/m3
) kills a human in about 1 min.
Check Digit Verification of cas no
The CAS Registry Mumber 74-90-8 includes 5 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 2 digits, 7 and 4 respectively; the second part has 2 digits, 9 and 0 respectively.
Calculate Digit Verification of CAS Registry Number 74-90:
(4*7)+(3*4)+(2*9)+(1*0)=58
58 % 10 = 8
So 74-90-8 is a valid CAS Registry Number.
InChI:InChI=1/CN/c1-2/q-1/p+1
74-90-8Relevant articles and documents
-
Howard,Hilbert
, p. 1918,1921, 1922 (1938)
-
Observation of high vibrational excitation in HCN molecules produced from 193 nm photolysis of 1,3,5-triazine
Goates, S. R.,Chu, J. O.,Flynn, G. W.
, p. 4521 - 4525 (1984)
Infrared emission from the ν2 bending mode and ν3 C-H stretching mode of HCN have been observed following 193 nm pulsed excimer laser photolysis of 1,3,5-triazine.Using a simple harmonic oscillator analysis, the number of ν2 bending quanta produced in HCN from photolysis of sym-triazine was found to be 70 times larger than the number of ν3 C-H stretching quanta.The combination of a high density of bending vibrational states in HCN and favorable geometry changes which occur in going from 1,3,5-triazine to three HCN molecules, appear to give an unusually pure distribution which maximizes vibrational energy in the HCN bending mode.
King, C. M.,Nixon, E. R.
, p. 1685 - 1695 (1968)
Multicomponent reaction of conjugated enynones with malononitrile and sodium alkoxides: Complex reaction mechanism of the formation of pyridine derivatives
Kuznetcova, Anastasiya V.,Odin, Ivan S.,Golovanov, Alexander A.,Grigorev, Iakov M.,Vasilyev, Aleksander V.
, p. 4516 - 4530 (2019)
Reaction of conjugated enynones,1,5-diarylpent-2-en-4-yn-1-ones, with malononitrile and sodium alkoxides in the corresponding alcohols at room temperature for 3–23 h results in the formation of two types of compounds (E)-/(Z)-6-aryl-4-(2-arylethenyl)-2-alkoxypyridine-3-carbonitriles (substituted nicotinonitriles), as the major reaction products in yields up to ca. 40–80%, and 6-aryl-4-arylethynyl-2-alkoxypyridines, as the minor reaction products in yields of 5–17%. Plausible mechanism of this complex and multistep reaction is discussed. The obtained pyridines possess fluorescent properties.
Yates,Heider
, p. 4153 (1952)
Investigations of Small Carbon Cluster Ion Structures by Reactions with HCN
Parent, Denise C.,McElvany, Stephen W.
, p. 2393 - 2401 (1989)
The results of a detailed study of the primary and secondary reactions of carbon cluster ions, Cn(1+) (3=20), with HCN are used as a probe of the structures of small carbon cluster ions.The experiments were performed in a Fourier transform ICR mass spectrometer (FTMS), using direct laser vaporization of graphite to form the carbon cluster ions.The only ionic products observed for the HCN reactions were CnX(1+) (primary reaction product) and CnXY(1+) (secondary reaction product) where X and Y = H, CN, or HCN.Radiative association is an important reaction channel.Products resulting from fragmentation of the reactant carbon cluster ion were not observed.Evidence for two structural forms of the n = 7-9 cluster ions is presented.The anomalous behavior of C7(1+) is interpreted by an isomerization mechanism.Low-energy collision-induced dissociation studies of the primary product ions support a mechanism of carbene insertion into the H-CN bond and formation of covalently bonded products.In contrast, the HCN associates weakly with most primary product ions.
Analysis of products from a C2H2/N2 microwave discharge: New nitrile species
Fujii, Toshihiro
, p. 733 - 740 (1999)
The production of gaseous hydrocarbons, nitriles, amines, and hydrazines in a continuous-flow microwave plasma discharge excited in a 20% C2H2+80% N2 mixture at a pressure of 20 Torr is reported. The product analysis was made by Li+ ion attachment mass spectrometry. A variety of N-containing organics (identified as HCnN (n=1-7), NC(CC)nCN (n=0-2), NC(CH2)nCN (n=0-6), CnH2n-1NH2 (n=0-6), CnH2n+1N(H)NH2 (n=0-5), etc.) were formed and these were tentatively assigned to nitriles, amines, and hydrazines. The mass-spectral analysis exhibited progressions differing by 14 mass units. Reaction schemes were proposed to explain the formation of some molecules.
Charge-transfer complexes of hypoglycemic sulfonamide with π-acceptors: Experimental and DFT-TDDFT studies
Soltani, Sara,Magri, Pierre,Rogalski, Marek,Kadri, Mekki
, p. 105 - 116 (2019)
Charge-transfer interactions (CT) between the electron donor gliclazide (GLC) and the π-acceptors 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and tetracyanoethylene (TCNE) were studied in a chloroform solution and in the solid state. The CT complexes were discussed in terms of formation constants (KCT), molar extinction coefficients (εCT), standard reaction quantities (ΔG° ΔH° and ΔS°), oscillator strength (f), transition dipole moment (μEN), and ionization potential (Ip). The limits of detection (LOD) and limits of quantification (LOQ) have also been reported. The stoichiometry of these complexes was found to be in a 1:1 M ratio. The formed solid CT complexes were also synthesized and characterized using electronic methods, FT-IR, 1H and 13C NMR spectroscopy. Thermogravimetric analysis techniques (TGA/DTA) and differential scanning calorimetry (DSC) were used to determine the thermal stability of the synthesized CT complex. The kinetic parameters (ΔG* ΔH* and ΔS*) were calculated from thermal decomposition data using the Coats-Redfern method. Moreover, density functional theory (DFT) studies are discussed for the charge transfer complex GLC-TCNE, using the B3LYP with 6–311++G (d, p) basis set. The harmonic vibrational frequencies were calculated, and the scaled values have been compared with experimental FT-IR spectra. The calculated 1H and 13C NMR chemical shifts using the GIAO method showed good correlations with the experimental data. The theoretical UV–visible spectrum of the compound and the electronic properties, such as HOMO and LUMO energies, were performed using the time-dependent (TD-DFT) approach with CAM-B3LYP, employing the 6–311++G (d, p) basis set, and good agreement with the theoretical and experimental UV–visible data was found.
Atakan, B.,Jacobs, A.,Wahl, M.,Weller, R.,Wolfrum, J.
, p. 449 - 453 (1989)
Gartaganis,Winkler
, p. 1457,1461 (1956)
Temperature Dependence of the Reaction of Nitrogen Atoms with Methyl Radicals
Marston, George,Nesbitt, Fred L.,Nava, David F.,Payne, Walter A.,Stief, Louis J.
, p. 5769 - 5774 (1989)
The discharge-flow mass spectrometry technique has been used to measure the kinetics of the reaction N + CH3 -> products over the temperature range 200-423 K.The results are as follows (10-11 cm3 s-1): k1(200 K)
Surface chemistry of CN bond formation from carbon and nitrogen atoms on Pt(111)
Herceg, Eldad,Trenary, Michael
, p. 17560 - 17566 (2005)
The mechanism of CN bond formation from CH3 and NH3 fragments adsorbed on Pt(111) was investigated with reflection absorption infrared spectroscopy (RAIRS), temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). The surface chemistry of carbon-nitrogen coupling is of fundamental importance to catalytic processes such as the industrial-scale synthesis of HCN from CH4 and NH3 over Pt. Since neither CH4 nor NH3 thermally dissociate on Pt(111) under ultrahigh vacuum (UHV) conditions, the relevant surface intermediates were generated through the thermal decomposition of CH 3I and the electron-induced dissociation of NH3. The presence of surface CN is detected with TPD through HCN desorption as well as with RAIRS through the appearance of the vibrational features characteristic of the aminocarbyne (CNH2) species, which is formed upon hydrogenation of surface CN at 300 K. The RAIRS results show that HCN desorption at a??500 K is kinetically limited by the formation of the CN bond at this temperature. High coverages of Cads suppress CN formation, but the results are not influenced by the coadsorbed I atoms. Cyanide formation is also observed from the reaction of adsorbed N atoms and carbon produced from the dissociation of ethylene. ? 2005 American Chemical Society.
-
Garner,Matsuno
, p. 1903 (1921)
-
Herries, D. G.,Richards, F. M.
, p. 1155 - 1156 (1964)
Suarez, M. Patricia,Loeffler, Daniel G.
, p. 240 - 242 (1986)
-
Onyszchuk,Winkler
, p. 368,369 (1955)
-
The hexacyanotitanate ion: Synthesis and crystal structure of [NEt4]3[Ti(III)(CN)6]·4MeCN
Entley, William R.,Treadway, Christopher R.,Wilson, Scott R.,Girolami, Gregory S.
, p. 6251 - 6258 (1997)
The hexacyanotitanate salt, [Et4N]3[Ti(CN)6]·4MeCN, has been prepared by addition of tetraethylammonium cyanide to the titanium(III) triflate salt Ti(O3SCF3)3(MeCN)3. The orange crystalline product has been characterized by X-ray diffraction, and the d1 anion is only slightly distorted from ideal O(h) symmetry. The anion resides on a center of symmetry and is characterized by the following parameters: Ti-C = 2.195(2), 2.197(3), and 2.213(3) A?; C-N (av) = 1.141(4) A?; C-Ti-C (cis) = 88.01(9), 88.02(9), 89.02(9), and 89.78(9)°; C-Ti-C (trans) = 180°. In addition to the crystallographic study, details of the IR (ν(CN) = 2071 cm-1), EPR, and UV-vis spectra (Δ(o) = 22800 cm-1) are given. Crystal data for [Et4N]3[Ti(CN)6]·4MeCN are as follows: monoclinic, space group I2/a, a = 18.171(6) A?, b = 12.200(4) A?, c = 20.989(5) A?, β = 91.17(2)°, V = 4652(2) A?3, Z = 4, wR2 = 0.2054 for 3831 data, 27 restraints, and 318 parameters.
Characterization of a carbon-nitrogen network solid with NMR and high field EPR
Rovnyak, David,Baldus, Marc,Itin, Boris A.,Bennati, Marina,Stevens, Andrew,Griffin, Robert G.
, p. 9817 - 9822 (2000)
Considerable attention has been focused on developing a synthetic route to a carbon-nitrogen material with mechanical and thermal properties comparable or superior to those of diamond. To date, no substance with the desired C3N4 stoichiometry in a silicon-nitride crystal lattice has been reported. One of the principal difficulties in the pursuit of ultrahard carbon-nitrogen (CN) solids is the characterization of amorphous CN samples. We describe a solid-state NMR study of a paracyanogen-like solid utilizing 13C-15N adiabatic-passage Hartmann-Hahn cross-polarization (APHH-CP) to perform dipolar filtering and show that this method is well-suited for recoupling 13C-15N in network solids. In addition, high-frequency electron paramagnetic resonance (EPR) indicates a density of electron spins of approximately 1 × 1017 e-/cm3. We conclude by discussing how NMR and EPR data may be useful for optimizing CN-polymer samples as potential precursors for ultrahard carbon nitrogen solids.
-
Fosse,Hieulle
, (1922)
-
Hasenberg, D.,Schmidt, L. D.
, p. 441 - 453 (1987)
Bassett, H.,Corbet, A. S.
, p. 1358 - 1358 (1924)
Facile Synthesis of the Dicyanophosphide Anion via Electrochemical Activation of White Phosphorus: An Avenue to Organophosphorus Compounds
Liu, Liu Leo,Mei, Yanbo,Yan, Zeen
supporting information, p. 1517 - 1522 (2022/02/01)
Organophosphorus compounds (OPCs) have gained tremendous interest in the past decades due to their wide applications ranging from synthetic chemistry to materials and biological sciences. We describe herein a practical and versatile approach for the trans
Large Faraday Rotation in Optical-Quality Phthalocyanine and Porphyrin Thin Films
Nelson, Zachary,Delage-Laurin, Leo,Peeks, Martin D.,Swager, Timothy M.
supporting information, p. 7096 - 7103 (2021/05/29)
The magneto-optical phenomenon known as Faraday rotation involves the rotation of plane-polarized light as it passes through an optical medium in the presence of an external magnetic field oriented parallel to the direction of light propagation. Faraday rotators find applications in optical isolators and magnetic-field imaging technologies. In recent years, organic thin films comprised of polymeric and small-molecule chromophores have demonstrated Verdet constants, which measure the magnitude of rotation at a given magnetic field strength and material thickness, that exceed those found in conventional inorganic crystals. We report herein the thin-film magnetic circular birefringence (MCB) spectra and maximum Verdet constants of several commercially available and newly synthesized phthalocyanine and porphyrin derivatives. Five of these species achieved maximum Verdet constant magnitudes greater than 105 deg T-1 m-1 at wavelengths between 530 and 800 nm. Notably, a newly reported zinc(II) phthalocyanine derivative (ZnPc-OT) reached a Verdet constant of -33 × 104 deg T-1 m-1 at 800 nm, which is among the largest reported for an organic material, especially for an optical-quality thin film. The MCB spectra are consistent with resonance-enhanced Faraday rotation in the region of the Q-band electronic transition common to porphyrin and phthalocyanine derivatives, and the Faraday A-term describes the electronic origin of the magneto-optical activity. Overall, we demonstrate that phthalocyanines and porphyrins are a class of rationally designed magneto-optical materials suitable for applications demanding large Verdet constants and high optical quality.
Trapping of Br?nsted acids with a phosphorus-centered biradicaloid - synthesis of hydrogen pseudohalide addition products
Beer, Henrik,Bl?sing, Kevin,Bresien, Jonas,Chojetzki, Lukas,Schulz, Axel,Stoer, Philip,Villinger, Alexander
supporting information, p. 13655 - 13662 (2020/10/27)
The trapping of classical hydrogen pseudohalides (HX, X = pseudohalogen = CN, N3, NCO, NCS, and PCO) utilizing a phosphorus-centered cyclic biradicaloid, [P(μ-NTer)]2, is reported. These formal Br?nsted acids were generatedin situas gases and passed over the trapping reagent, the biradicaloid [P(μ-NTer)]2, leading to the formation of the addition product [HP(μ-NTer)2PX] (successful for X = CN, N3, and NCO). In addition to this direct addition reaction, a two-step procedure was also applied because we failed in isolating HPCO and HNCS addition products. This two-step process comprises the generation and isolation of the highly reactive [HP(μ-NTer)2PX]+cation as a [B(C6F5)4]?salt, followed by salt metathesis with salts such as [cat]X (cat = PPh4,n-Bu3NMe), which also gives the desired [HP(μ-NTer)2PX] product, with the exception of the reaction with the PCO?salt. In this case, proton migration was observed, finally affording the formation of a [3.1.1]-hetero-propellane-type cage compound, an OC(H)P isomer of a HPCO adduct. All discussed species were fully characterized.
