13826-83-0

Basic information

• Product Name: Ammonium fluoborate
• Synonyms: ammoniumfluoroborate[qr];ammoniumtetrafluoroborate(1-);ammoniumtetrafluoroborate(1-)[qr];ammoniumtetrafluoroborate[qr];Borate(1-),tetrafluoro-,ammonium;tetrafluoro-borate(1-ammonium;tetrafluoro-borate(1-ammonium[qr];AMMONIUM FLUOROBORATE
• CAS NO: 13826-83-0
• Molecular Formula: BF₄*H₄N
• Molecular Weight: 104.84
• EINECS: 237-531-4
• Product Categories: Industrial/Fine Chemicals;Inorganics;halometallate salts;Ammonium Salts;Materials Science;Metal and Ceramic Science;Salts;Fluoride;resin finishing catalyst in printing
• Mol File: 13826-83-0.mol

Chemical Properties

• Melting Point: 230 °C
• Appearance: White/Powder
• Density: 1.871 g/mL at 25 °C(lit.)
• Storage Temp.: Store below +30°C.
• Water Solubility: soluble
• Sensitive: Moisture Sensitive
• CAS DataBase Reference: Ammonium fluoborate(CAS DataBase Reference)
• NIST Chemistry Reference: Ammonium fluoborate(13826-83-0)
• EPA Substance Registry System: Ammonium fluoborate(13826-83-0)

Safety Data

• Hazard Codes: C
• Statements: 36/37/38-34
• Safety Statements: 26-36-45-36/37/39
• RIDADR: UN 9088
• WGK Germany: 3
• RTECS: BQ6100000
• TSCA: T
• HazardClass: MOISTURE SENSITIVE, CORROSIVE
• Hazardous Substances Data: 13826-83-0(Hazardous Substances Data)

Usage

Uses

Used in Analytical Chemistry:
Ammonium fluoborate is used as an analytical reagent in the field of chemistry. It is particularly useful for its ability to dissolve certain substances that are otherwise difficult to analyze, making it a valuable tool for researchers and scientists.
Used in Textile Printing and Dyeing Industry:
In the textile industry, ammonium fluoborate is applied as a catalyst for resin finishing. Its use in this industry is due to its ability to enhance the quality and durability of the finished product, leading to improved performance and appearance.
Used in Metals Industry:
Ammonium fluoborate is primarily used for the high-temperature fluxing action required by the metals industry. It helps in the smelting process by lowering the melting point of metals, making it easier to extract them from their ores.
Used as a Catalyst:
Ammonium fluoborate also serves as a catalyst in various chemical reactions, speeding up the process and increasing the efficiency of the reaction. Its catalytic properties make it a valuable component in the production of various chemicals and materials.
Used in Flame Retardants:
In the field of fire safety, ammonium fluoborate is used as a component in flame retardants. Its inclusion in these products helps to slow down the spread of fire, providing additional protection against火灾 (fire).
Used as a Solid Lubricant:
Lastly, ammonium fluoborate acts as a solid lubricant in cutting-oil emulsions for aluminum rolling and forming. Its use in this application is due to its ability to reduce friction and wear, leading to smoother and more efficient manufacturing processes.

Air & Water Reactions

Sublimes above 238°C. to form toxic fumes [AAR 1991]. Water soluble.

Reactivity Profile

Acidic inorganic salts are generally soluble in water. The resulting solutions contain moderate concentrations of hydrogen ions and have pH's of less than 7.0. They react as acids to neutralize bases. These neutralizations generate heat, but less or far less than is generated by neutralization of inorganic acids, inorganic oxoacids, and carboxylic acid. They usually do not react as either oxidizing agents or reducing agents but such behavior is not impossible. Many of these compounds catalyze organic reactions.

Health Hazard

INHALATION: May cause irritation of respiratory passages, nose bleeds, and nausea. EYES: May irritate.

Fire Hazard

Behavior in Fire: Sublimes above 238°C yielding toxic fumes.

Safety Profile

A poison and strong irritant. See also FLUORIDES and BORON COMPOUNDS. When heated to decomposition it emits very toxic fumes of F-, NO,, and NH3.

Purification Methods

Crystallise it from conductivity water (1mL/g) between 100o and 0o. 450 Purification of Inorganic Compounds

InChI:InChI=1/BF4.H3N/c2-1(3,4)5;/h;1H3/q-1;/p+1

Synthetic route

ammonium hydroxide + pyridinium tetrafluoroborate → pyridine (110-86-1) + ammonium tetrafluroborate (13826-83-0)

Conditions	Yield
In water dropwise addn. of NH4OH to C5H5NHBF4; extn. of pyridine with CHCl3 three times, filtration of the aq. soln., slow evapn. on a water-bath at 60 - 70°C, pptn., drying in vac. over P2O5, elem. anal.;	A n/a B 92%

{((η5-C5H5)Mo)2(S2CH2)(μ-S)(μ-SH)}BF4 + propiononitrile (107-12-0) → ammonium tetrafluroborate (13826-83-0) + {((η5-C5H5)Mo)(S2CH2)(S2CCH2CH3)(Mo(η5-C5H5))}BF4

Conditions	Yield
With hydrogen In neat (no solvent) dry solvents; degassing Mo-compd. dissolved in EtCN, placing under hydrogen (400 Torr at -196°C), stirring react. mixt. at room temperature (1 day); removal of solvent under reduced pressure, extn. (water), dissolving in MeCN, pptn. by addn. of Et2O; elem. anal.;	A 47% B 40%

{((η5-C5H5)Mo)2(S2CH2)(μ-S)(μ-SH)}BF4 + benzonitrile (100-47-0) → ammonium tetrafluroborate (13826-83-0) + {((η5-C5H5)Mo)(S2CH2)(S2CC6H5)(Mo(η5-C5H5))}BF4

Conditions	Yield
With hydrogen In benzonitrile dry solvents; degassing Mo-compd. dissolved in PhCN, placing under hydrogen (400 Torr at -196°C), stirring react. mixt. at room temperature (1 day); removal of solvent under reduced pressure, extn. (water), , dissolving in MeCN, pptn. by addn. of Et2O;	A 39% B 30%

{((η5-C5H5)Mo)2(S2CH2)(μ-S)(μ-SH)}BF4 + acetonitrile (75-05-8) → ammonium tetrafluroborate (13826-83-0) + {((η5-C5H5)Mo)(S2CH2)(S2CCH3)(Mo(η5-C5H5))}BF4

Conditions	Yield
With hydrogen In acetonitrile dry solvents; degassing Mo-compd. dissolved in acetonitrile, placing under hydrogen (400 Torr at -196°C), stirring react. mixt. at room temperature (1 day); removal of solvent under reduced pressure, extn. (water), dissolving in MeCN, pptn. by addn. of Et2O;	A 32% B 35%

ammonium thiocyanate + 2-methylphenyl diazonium tetrafluoroborate (2093-46-1) → ammonium tetrafluroborate (13826-83-0) + nitrogen (7727-37-9)

Conditions	Yield
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; dimethyl sulfoxide byproducts: 2-MeC6H4CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 2-MeC6H4N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.), Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMSO (1:4) for 30 min; evolution of gas at 10-15°C for 45 min;
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; N,N-dimethyl-formamide byproducts: 2-MeC6H4CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 2-MeC6H4N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.), Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMF (1:3)for 30 min; evolution of gas at 10-15°C for 45 min;

ammonium thiocyanate + 1,4-Butanediol diacrylate (1070-70-8) + benzenediazonium tetrafluoroborate (369-57-3) → ammonium tetrafluroborate (13826-83-0) + nitrogen (7727-37-9) + 4-(2-thiocyanato-3-phenylpropionyloxy)butyl acrylate

Conditions	Yield
copper(II) bis(tetrafluoroborate) In water; acetone addn. of C6H5N2BF4 to 1,4-bis(acryloyloxy)butane, Cu(BF4)2 and NH4SCN inaq. acetone (1:2) for 45-60 min; cooling at -10 - -5°C for 2 h; evolution of N2, treatment of residual with Et2O, extn., washing with water, drying with MgSO4, removal of ether, chromy.;

ammonium thiocyanate + 1,4-Butanediol diacrylate (1070-70-8) + 4-nitrobenzenediazonium tetrafluoroborate (456-27-9) → ammonium tetrafluroborate (13826-83-0) + nitrogen (7727-37-9) + acrylic acid 4-[3-(4-nitro-phenyl)-2-thiocyanato-propionyloxy]-butyl ester

Conditions	Yield
copper(II) bis(tetrafluoroborate) In water; acetone addn. of NO2C6H4N2BF4 to 1,4-bis(acryloyloxy)butane, Cu(BF4)2 and NH4SCNin aq. acetone (1:2) for 45-60 min; cooling at -10 - -5°C for 2 h; evolution of N2, treatment of residual with Et2O, extn., washing with water, drying with MgSO4, removal of ether, chromy.;

ammonium thiocyanate + 1,4-Butanediol diacrylate (1070-70-8) + 4-methylbenzenediazonium tetrafluoroborate (459-44-9) → ammonium tetrafluroborate (13826-83-0) + nitrogen (7727-37-9) + acrylic acid 4-(2-thiocyanato-3-p-tolyl-propionyloxy)-butyl ester

Conditions	Yield
copper(II) bis(tetrafluoroborate) In water; acetone addn. of CH3C6H4N2BF4 to 1,4-bis(acryloyloxy)butane, Cu(BF4)2 and NH4SCNin aq. acetone (1:2) for 45-60 min; cooling at -10 - -5°C for 2 h; evolution of N2, treatment of residual with Et2O, extn., washing with water, drying with MgSO4, removal of ether, chromy.;

ammonium thiocyanate + 2,5-dichloroaniline diazonium fluoroboric salt → ammonium tetrafluroborate (13826-83-0) + nitrogen (7727-37-9)

Conditions	Yield
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; dimethyl sulfoxide byproducts: 2,5-Cl2C6H3CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 2,5-Cl2C6H3N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.) , Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMSO (1:4) for 30 min; evolution of gas at 10-15°C for 45 min;
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; N,N-dimethyl-formamide byproducts: 2,5-Cl2C6H3CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 2,5-Cl2C6H3N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.) , Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMF (1:3) for 30 min; evolution of gas at 10-15°C for 45 min;

ammonium thiocyanate + 4-methoxybenzenediazonium tetrafluoroborate (459-64-3) → ammonium tetrafluroborate (13826-83-0) + nitrogen (7727-37-9)

Conditions	Yield
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; dimethyl sulfoxide byproducts: 4-MeOC6H4CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 4-MeOC6H4N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.), Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMSO (1:4) for 30 min; evolution of gas at 10-15°C for 45 min;
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; N,N-dimethyl-formamide byproducts: 4-MeOC6H4CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 4-MeOC6H4N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.) , Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMF (1:3) for 30 min; evolution of gas at 10-15°C for 45 min;

ammonium thiocyanate + benzenediazonium tetrafluoroborate (369-57-3) → ammonium tetrafluroborate (13826-83-0) + nitrogen (7727-37-9)

Conditions	Yield
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; dimethyl sulfoxide byproducts: C6H5CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of PhN2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.), Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMSO (1:4) for 30 min; evolution of gas at 10-15°C for 45 min;
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; N,N-dimethyl-formamide byproducts: C6H5CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of PhN2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.), Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMF (1:3) for 30 min; evolution of gas at 10-15°C for 45 min;

ammonium thiocyanate + 4-nitrobenzenediazonium tetrafluoroborate (456-27-9) → ammonium tetrafluroborate (13826-83-0) + nitrogen (7727-37-9)

Conditions	Yield
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; N,N-dimethyl-formamide byproducts: 4-NO2OC6H4CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 4-NO2C6H4N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.), Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMF (1:3) for 30 min; evolution of gas at 10-15°C for 45 min;
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; dimethyl sulfoxide byproducts: 4-NO2OC6H4CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 4-NO2C6H4N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.) , Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMSO (1:4) for 30 min; evolution of gas at 10-15°C for 45 min;

ammonium thiocyanate + 4-methylbenzenediazonium tetrafluoroborate (459-44-9) → ammonium tetrafluroborate (13826-83-0) + nitrogen (7727-37-9)

Conditions	Yield
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; dimethyl sulfoxide byproducts: 4-MeC6H4CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 4-MeC6H4N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.), Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMSO (1:4) for 30 min; evolution of gas at 10-15°C for 45 min;
With N,N-methylediacrylamide; copper(II) tetrafluroborate hexahydrate In water; N,N-dimethyl-formamide byproducts: 4-MeC6H4CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 4-MeC6H4N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.), Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMF (1:3)for 30 min; evolution of gas at 10-15°C for 45 min;

ammonium thiocyanate + 3-methylbenzenediazonium tetrafluoroborate (1422-76-0) → ammonium tetrafluroborate (13826-83-0) + nitrogen (7727-37-9)

Conditions	Yield
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; N,N-dimethyl-formamide byproducts: 3-MeC6H4CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 3-MeC6H4N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.) , Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMF (1:3) for 30 min; evolution of gas at 10-15°C for 45 min;
With N,N-methylenediacrylamide; copper(II) tetrafluroborate hexahydrate In water; dimethyl sulfoxide byproducts: 3-MeC6H4CH2CH(SCN)CONHCH2NHCOCHCH2; addn. of 3-MeC6H4N2BF4 (1.1 equiv.) to N,N-methylenediacrylamide (1 equiv.) , Cu(BF4)2*6H2O (0.1 equiv.) and NH4SCN (1.1 equiv.) in H2O-DMSO (1:4) for 30 min; evolution of gas at 10-15°C for 45 min;

tetrafluoroboric acid + ammonia (7664-41-7) → ammonium tetrafluroborate (13826-83-0)

nitrosylchloroborate (69525-31-1) + ammonium chloride → ammonium tetrafluroborate (13826-83-0)

boron trifluoride amine (1092538-47-0) → boron nitride (10043-11-5) + ammonium tetrafluroborate (13826-83-0)

Conditions	Yield
125-150°C;
125-150°C;

boron trifluoride amine (1092538-47-0) → ammonium tetrafluroborate (13826-83-0)

Conditions	Yield
In neat (no solvent) optimum conditions discussed;; 252°C, 36h, N2;;
by heating;
by heating;

boron trifluoride amine (1092538-47-0) + water (7732-18-5) → ammonium tetrafluroborate (13826-83-0)

Conditions	Yield
In neat (no solvent) heating in H2O containing atmosphere;;

Upstream product

• 2093-46-1 2-methylphenyl diazonium tetrafluoroborate 
• 1070-70-8 1,4-Butanediol diacrylate 
• 369-57-3 benzenediazonium tetrafluoroborate 
• 456-27-9 4-nitrobenzenediazonium tetrafluoroborate 
• 459-44-9 4-methylbenzenediazonium tetrafluoroborate 
• 459-64-3 4-methoxybenzenediazonium tetrafluoroborate 
• 1422-76-0 3-methylbenzenediazonium tetrafluoroborate 
• 7664-41-7 ammonia 
• 69525-31-1 nitrosylchloroborate 
• 1092538-47-0 boron trifluoride amine 
• 7732-18-5 water 
• 11113-50-1 boric acid 
• 7664-39-3 hydrogen fluoride 
• 16961-83-4 fluorosilicic acid 

Downstream Products

• 170487-40-8 1H-indazole-6-carboxylic acid methyl ester 
• 199172-01-5 6-bromo-3-ethyl-1H-indazole 
• 53857-57-1 5-bromo-1H-indazole 
• 7789-24-4 lithium fluoride 
• 19287-45-7 diborane 
• 14104-20-2 silver tetrafluoroborate 
• 108548-16-9 (Pt(S₂N₂H)(P(C₆H₅)3)2)⁽¹⁺⁾*BF₄^(1-)=(Pt(S₂N₂H)(P(C₆H₅)3)2)BF₄ 
• 429-42-5 tetrabutylammonium tetrafluoroborate 
• 7637-07-2 boron trifluoride 
• 13755-29-8 sodium tetrafluoroborate 
• 420-56-4 trimethylsilyl fluoride 
• 10043-11-5 boron nitride 
• 122874-51-5 RhCO(tris(2-(diphenylphosphino)ethyl)phosphine) tetrafluoroborate 

Relevant articles and documents

Production and decomposition of (NH4)[BF4] and H3N-BF3

(NH4)[BF4] is produced as single crystals during the reaction of elemental boron and NH4HF2 (B:NH4HF2 = 1:2) and NH4F (B:NH4F = 1:4), respectively, in sealed copper ampoules at 300°C. The crystal structure (baryte type, orthorhombic, Pnma, Z = 4) was redetermined at ambient temperature (a = 909.73(18), b = 569.77(10), c = 729.47(11) pm, Rall = 0.0361) and at 140 K (a = 887.3(2), b = 574.59(12), c = 717.10(12)pm, Rall = 0.0321). Isolated (NH4)+ and [BF4]- tetrahedra are the important building units. The thermal behaviour of (NH4)[BF4] was investigated under inert (Ar, N2) and reactive conditions (NH3) with the aid of DTA/TG and DSC measurements and with in-situ X-ray powder diffraction as well. Finally, (NH4)[BF4] is decomposed yielding NH3 and BF3, BN is not produced under the current conditions. Colourless single crystals of H3N-BF3 were prepared directly from the components NH3 and BF3. The crystal structure was determined anew at 293 and 170 K (orthorhombic, Pbca, Z = 8, a = 815.12(10), b = 805.91(14), c = 929.03(12) pm, Rall = 0.0367; a = 807.26(13), b = 800.48(10), c = 924.31(11)pm, Rall = 0.0292, T = 170 K). The crystal structure contains isolated molecules H3N-BF3 in staggered conformation with a B-N distance of 158 pm. The thermal behaviour of H3N-BF3 was studied likewise.

Interaction of datolite concentrate with ammonium hydrodifluoride

The interaction of datolite concentrate with ammonium hydrodifluoride were studied. Under heating, ammonium hydrodifluoride fluorinates datolite to form complex fluoroammonium salts of boron, silicon, and impurity metals. The activation energy and rate constants were calculated for the reaction of datolite concentrate with ammonium hydrodifluoride in the range 100-150°C. The composition of the vola-tiles formed upon the heating of the fluorinated concentrate was studied, the temperature parameters of the evolution of boron and silicon to the gas phase were determined, and a process for separating these elements was proposed. Pleiades Publishing, Ltd., 2010.

Reductive cleavage of the N-N bond of hydrazine induced by a cationic trinuclear ruthenium hexahydride complex, [(Cp'Ru)3(μ-H) 6]X (Cp' = ν5-C5Me5; X = 1/2 SO4, BF4, PF6, BPh4) and dihydrogen

The reaction of the monocationic triruthenium hexahydride [(Cp'Ru) 3(μ-H)6]X (1; X = 1/2 SO4, BF4, PF6, BPh4) with hydrazine leads to the formation of the mono(μ3-imido) complex (Cp'Ru)3(μ3-NH) (μ-H)3 (3) and the triruthenium pentahydride complex (Cp'Ru) 3(μ3-H)2(μ-H)3 (2). Complex 1 is in equilibrium with 2 in the presence of NH4X or N 2H5X, and complex 1 is regenerated upon treatment of 2 with such a protic salt. Complex 3 further reacts with hydrazine to yield the bis(μ3-imido) complex (Cp'Ru)3(μ3-NH) 2(μ-H) (4) as a result of cleavage of the nitrogen-nitrogen bond, which is formally catalyzed by a proton. Both 3 and 4 undergo hydrogenation to generate 2 together with ammonia. Thus, reductive cleavage of the nitrogen-nitrogen bond of hydrazine leading to ammonia is achieved by the use of the monocationic trinuclear hexahydride complex 1 and dihydrogen under conditions without any added proton source and a reducing agent.

Reaction of arenediazonium tetrafluroborates with N,N-methylenediacryalmide in the presence of thiocyanate anions

The reactions of arenediazonium tetrafluoroborates with N,N-methylenediacrylamide in H2O-DMF (1:3) and H2O-DMSO (1:4) in the presence of thiocyanate anions involve thiocyanatoarylation by one or two multiple bonds to give [(3-aryl-2-

Reactions of arenediazonium tetrafluoroborates with 1,4-bis(acryloyloxy)butane in the presence of thiocyanate ion

The first thiocyanatoarylation reaction with an unsaturated compound containing two isolated multiple bonds, 1,4-bis(acryloyloxy)butane, was effected. The reactions of 1,4-bis(acryloyloxy)butane with arenediazonium tetrafluoroborates occur in aqueous acet

Reactions of a sulfido-bridged dinuclear molybdenum complex with nitriles and isonitriles under hydrogen: Facile C≡N bond cleavage

The dinuclear complex [(CpMo)2(S2CH2)(μ-S)(μ-SH)] +X- (X = SO3CF3, BF4; Cp = C5H5; 1(X)) reacted with nitriles RCN under 1-2 atm of H2 at 25-50°C to form the new cationic complex [CpMo(S2CH2)(S2CR)MoCp]+ and ammonia. The reaction has been characterized for HCN as well as for a series of alkyl- and aryl-substituted nitriles. Complex 1 reacted with isonitriles (RNC) and hydrogen under similar conditions to form the cationic complex [CpMo(S2CH2)(S2CH)MoCp]+ and the primary amine RNH2. The reactions were inhibited by excess acid. In order to probe the mechanisms of these reactions, the interactions of nitriles and isonitriles with 1 in the absence and presence of a protic acid and in the absence and presence of hydrogen have been studied. In the absence of hydrogen, 1 reacted with isonitriles to form [(CpMo)2(S2CH2)(S2CNH(R))] + (2), but no reaction of 1 with nitriles was detected spectroscopically. Under similar conditions in the presence of excess protic acid, 1 reacted with n-butyl isocyanide to form [(CpMo)2(S2CH2)(μ-S)(μ-SCH=NHBu)] 2+ (4) and with acetonitrile to form [(CpMo)2(S2CH2)(μ-S)(μ-SC(CH 3)=NH2)]2+ (5). These S-H insertion products were identified by spectroscopic methods. The reaction of 4 and 5 with hydrogen appeared to involve carbon-sulfur bond hydrogenolysis; e.g., in the reaction of 5 with H2, ethylammonium ion was identified as a product. The C-N bond cleavage reactions are proposed to involve the deprotonated forms of the insertion products 4 and 5, [(CpMo)2(S2CH2)(μ-S)(μ-SCH=NBu)] + and [(CpMo)2(S2CH2)(μ-S)(μ-SC(CH 3)=NH)]+. The former complex was tentatively identified by NMR spectroscopy. Reactions of these derivatives with hydrogen are proposed to lead to intramolecular S-H insertion products [(CpMo)2(S2CH2)(S2CH(NH 2Bu))]+ (6) and [(CpMo)2(S2CH2)(S2C(CH 3)NH3)]+ (7). A precedent for this type of reaction has been characterized in a related molybdenum system. Complexes 6 and 7 are expected to eliminate BuNH2 and NH3, respectively, to form the final molybdenum products. The possible relevance of these reactions to the reductions of nitriles and isonitriles effected by the nitrogenase enzymes is discussed.