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New xanthato nickel complexes
3166
Notes
Several observations were made for each of the samples and the average results are shown in Table 1, where the Mg to Fe ratio relative to the standard is expressed as a % excess of magnesium. These figures are therefore directly comparable with the parameter x (when this is expressed as a percentage) in the formula (MgO)x • MgFe204 used by Paladino, except that no claim concerning the oxygen content is made in our case. Table !. Mg to Fe ratio relative to equimolar standard Specimen
Magnesium excess(%)
Check sample with 5% Mg excess Check sample with 5% Mg deficiency Sample sintered at 1100"(2 Sample sintered at 1200°C Sample sintered at 1400°C
4'0±0.8 --5"6±1"5 6'9±1"1 5"7±1"0 6-3±1"0
CONCLUSIONS Although our measurements do not reveal information concerning oxygen content, it is clear that the present results are consistent with the earlier conclusions drawn by Paladino. His equilibrium value for x is somewhat higher than the average magnesium excess given here. However, it is noteworthy that within our experimental uncertainty this excess is also independent of sintering temperatures at least up to 1400°C. It is also evident that the present results do not support Reijnen's claim for the existence of stoichiometric MgFe204 spinel, in spite of the fact that we have followed his recommendations concerning preparation.
Department of Physics University of Aston in Birmingham Gosta Green, Birmingham 4 England
T. V I L A I T H O N G * D. C R U M P T O N P.E. FRANCOIS N.W. GRIMES
*On leave from the University of Chiengmai. In receipt of a grant from the British Council.
J. inorg, nucl. Chem., 197 I, Vol. 33, pp. 3166 to 3169.
P~rgamon Press.
Printed in Great Britain
New xanthato nickel complexes (Received 11 February 1971) A XANTHATE ion generally acts as a bidentate ligand in the complexes it forms with transition metals. I.R. studies of these complexes have shown that they may be described by three canonical forms (Fig. 1). Forms b and c, are the nearest of the true electronic structure. These structures, in which the electronic interaction between the sulfurs and the Px nickel orbital is the lowest, are the more favorable
(a)
(b)
Fig. 1.
(c)
Notes
3167
for the formation of adducts with nitrogenous bases. This interaction, which is more marked in the case of dithiocarbamates and especially dithiolates, explains their different behavior towards nitrogenous bases, mainly for dithiolates. On the other hand, study of complexes such as L2Au (dialkyldithiocarbamate)[2] and L2Sn (dialkyldithiocarbamate)2 [3] has shown that an increase in the electron withdrawing character of L. causes a decrease in the contribution of forms b and c (Fig. 1). We have tried to synthetize new xanthate complexes in which the electronic environment of the nickel can be changed by varying the nature of the ligands used, and to study them. For bis(alkylxanthate) nickel we substituted one of the alkylxanthate anions by a halogen atom, and the new complexes thus obtained were stabilized with tertiary phosphine. The formula of the compounds thus obtained is represented in Fig. 2. R_O_..C,~,S~ Ni/X "~S/ Fig. 2.
~pR 3
These compounds are generally synthetized by the reaction between a bis(alkylxanthate) nickel and a nickel halogenide complexed by two molecules of phosphine in a solvent such as diethyl ether or benzene. We have observed that, starting from uncomplexed nickel halogenide, adding phosphine to the reaction medium results in a decrease in the reaction rate in the order I > Br > CI which seems to indicate that the limitative step of the reaction is the formation of the complexe X2Ni(PR3)2. It is interesting to note that sometimes, with nickel methylxanthate as the starting material, derivative of methylthiol are obtained. The reaction of a hydracid with a nickel xanthate together with phosphine in diethyl ether gives products with the same aspect as those obtained in other ways but for which the analysis are not entirely satisfactory. A N M R study of the compounds thus obtained shows the presence of an ethyl group (Hen31"= 7'2 ppm, Hcns'r = 5'02 ppm, Zcn3cn, = 0"13 ppm in the compound G) whose origin can presumably be found in the action of hydracid on diethyl ether. Unfortunately, we are not yet able to fully define the position of this ethyl radical in these complexes. The complexes represented in Fig. 2 are not very stable and cannot be stored long in air. They are soluble in a number of organic solvents in which they are stabilized by an excess of phosphine. The molecular weights measured in acetonitrile indicate that they are slightly dissociated monomeres. Their electronic spectra are characteristic of square planar structures. For instance, the following transitions are observed for iodo (ethylxanthate) (triphenylphosphine) nickei(II) in acetonitrile: JA1o-+1A2o 18,200cm -1 ( e = 2 6 0 ) JAlo--+lBza 21,000cm -1 ( e = 5 4 0 ) JA1o--~IEo 24,100cm -~ (~ = 1200). The diamagnetism of these compounds is consistent with a square planar structure. Small shifts in the C - - O frequency are observed in their i.r. spectra. It is possible that, due to their polarization, the phosphines play a compensating part in the electron withdrawing nature of the halogen. It is interesting to note that some of these complexes seem to form adducts with another molecule of phosphine at low temperature resulting in a pentaccordinated nickel. Complexes with similar structure have already been described [5, 6]. EXPERIMENTAL Bis(alkylxanthate)nickel and dihalogeno bis(phosphine)nickel were prepared by published methods [7, 8]. 1. D. N. Coucouvanis, Ph.D. Thesis, University of Cleveland (1967). 2. H . J . A . Blaauw, R. J. F. Nivard and G. J. M. Van der Kerk, J. organomet. Chem. 2, 236 (1964). 3. M. Honda, M. Komura, Y. Kawasaki, T. Tanaka and R. Okawara, J. inorg, nucl. Chem. 30, 3231 (1968). 4. G. Maki, J. chem. Phys. 29, 162 (1958). 5. D. Walter, G. Wilke, Angew. Chem. 78, 941 (1966). 6. F. Guerrieri and G. P. Chiusolo, J. organomet. Chem. 15,209 (1968). 7. G.W. Watt and B. J. McCormick, J. inorg. Chem. 27,898 (1965). 8. L. M. Venanzi, J. chem. Soc. 719 (1958).
3168
Notes
I.R. Spectra were recorded on a Perkin-Elmer 457, electronic spectra on a Perkin-Elmer 402, N M R spectra by Mr. J. C. Roussel on a Varian A 60.
A. Bromo( ethylxant hate)( triphe nyl phosphine )nickel( l l ) 0"6 of nickel ethylxanthate are dissolved in 100 ml of diethyl ether with good stirring. 1"3 g of nickel bis(triphenylphosphine)bromide are added. The solution becomes red, is stirred during one hour allowed to stand for the night and filtered. The violet crystals are dissolved in 30 ml of benzene containing 0-2 g of triphenylphosphine. The solution is reduced to 10 ml and allowed to crystallize during two days. 1.2 g of violet crystals are collected Pt = 108-109 °. Anal. Calcd. For C2tH~0OSsNiBrP: C, 48"31; H, 3.86; S, 12"28; Ni, 11"24; Br, 15.30; P, 5.93. Found: C, 48.33; H, 3.92; S, 12.13; Ni, 11"39; Br, 15.41; P, 5"77.
B. l odo( ethylxanthate )( triphenylphosphine )nickel( l l ) (a) In the same way as for the bromo derivative A, using nickel bis(triphenylphosphine)iodide, 1"25 g brown crystals are obtained pt = 118-119 °. Anal. Calcd. For C~H~0OS2NilP: C, 44.32; H, 3.54; S, 11"27; Ni, 10"32; I, 22.30; P, 5.44. Found: C, 44"33; H, 3.32; S, 11"76; Ni, 10-76; I, 22"40; P, 5.57. (b) 1-8 g of nickel ethylxanthate are dissolved in 1000 ml of diethyl ether, and 3 g of nickel iodide and 3.15 g of triphenyl phosphine are added while stirring. Stirring is maintained during two days during which time the solution becomes brown. Filtration gives a brown compound which is crystallized from benzene. Ps = 119". Anal. Found: C, 44.03; H, 3"88; S, 11 "38; Ni, 10.43; I, 22"48; P, 5"53.
C. C hloro( ethylxanthate )( triphenylphosphine )nickel( l l ) The same method is used as for the bromo derivative A, starting from nickel bis(triphenylphosphine)chloride; violet crystals (0.95 g) are obtained. Anal. Calcd. For C21H20OS2NiCIP: C, 52-81 ; H, 4.22; S, 13"43; Ni, 12.29; CI, 7.42; P, 6.48. Found: C, 52.64; H, 4.35; S, 13"24; Ni, 12' 11 ; CI, 7.46; P, 6"31.
D. l odo( isopropylxanthate )( triphenylphosphine )nic ke l( l l ) The same method as for the ethylxanthate derivative B(a) is used, starting from nickel isopropylxanthate; brown crystals are obtained (1.15 g). Anal. Calcd. For C22H22OS2NilP: C, 45"31; H, 3.80; S, 11.00; Ni, 10"07; I, 21-76; P, 5"31. Found: C, 45.51; H, 3.74; S, 10.86; Ni, 10"17; I, 21.97; P, 5.23.
E. l odo( ethylxanthate )( triphenylphosphine )nickel( l l ) In the same way as for the triphenylphosphine derivative B(b), using triphenylphosphite, 1.3 g of red brown crystals are obtainedps = 135-136 °. Anal. Calcd. For C21H~004S2NilP: C, 40.89; H, 3'25; S, 10.40; Ni, 9"52; I, 20-57; P, 5.02. Found: C, 40.76; H, 3.27; S, 10.55; Ni, 9.79; I, 20.66; P, 4.94.
F. C hloro( ethylxant hate)( tricyclohexyl phosphine )nickel( l l ) 1 g of nickel ethylxanthate, 2'4 g of tricyclohexylphosphine and 1 g of nickel chloride are dissolved with stirring in 20 ml of dimethoxyethane. The solution is warmed to 80°C and maintained at that temperature during 1 hr and filtered while hot. After standing for 2 days at room temperature, brown crystals are collected and recrystallized from benzene. Anal. Calcd. For CzlHasOS2NiC1P: S, 12.90; Ni, 11"89; C1, 7"16; P, 6.26. Found: S, 13-39; Ni, 12'32; CI, 7.21 ; P, 6.26.
G. Syntheses from hydracid 1 g of nickel methylxanthate are dissolved in 500 ml of diethylether together with 1.55 g of triphenylphosphine. While stirring, a solution of 0.85 ml BrH(d = 1.8) to 5 ml of absolute ethanol is
Notes
3169
added dropwise. The solution becomes red and a small amount of nickel bromide is formed. Stirring is maintained during 1 hr and the solution is filtered. The filtrate is reduced to 200 ml and left to stand for 2 days. 0.6 g of violet crystals are obtained. Anal. Calcd. For C22H2aOS~NiBrP: C, 49-21; H, 4.46; S, 11.88; Ni, 10.95; Br, 14.81; P, 5.76. Found: C, 49.29; H, 3.80; S, 11-87; Ni, 10"95; Br, 14.89; P, 5"62. H. Synthesis o f a thiol derivative The method described for preparing iodo(ethylxanthate)(triphenylphosphine) nickel Ba is used with nickel methylxanthate. Brown crystals are obtained. Anal. Calcd. For C~HIsSNilP: S, 6.48; Ni, 11.92; I, 25"68; P, 6.28. Found: S, 6-74; Ni, 12.21; 1, 26-31; P, 6.40. lnstitut Fran9ais du P~trole BP. 1 8 . 9 2 - R euil-Malmaison France
C. BLEJEAN J. L. C H E N O T
J. inorg,nucI.Chem., 1971.Vol.33, pp. 3169to 3171. PergamonPress. Printedin Great Britain
Raman spectrum of the NF~ radical* (First revived 14 September 1970; in revised form 4 January 1971 ) THE FREE radical NF2 was discovered by Colburn et a/.[1] at the beginning of the last decade. It results from dissociation of tetrafluorohydrazine at elevated temperatures. Several infrared studies of this radical have been reported. A study of the i.r. gas spectrum of NF~ by Harmony et a/.[2] permitted only the definite assignment of the symmetric stretching fundamental v~ at 1074.3 cm -1, although the gas spectrum indicated another band between 930 and 940 cm -~ almost obscured by N2F4 bands. A subsequent matrix isolation i.r. spectrum[3] located this latter band definitely, at 930.7 cm -j, and in addition a very weak band at 573.4 cm -~ which was assigned to the bending mode, vs. We felt it worthwhile to investigate the Raman spectrum of this system, since the totally symmetric bending frequency should be intense and sharp in the Raman spectrum and easily identifiable because it should be strongly polarized. Moreover, frequencies obtained in matrices, are occasionally shifted from the gas values, and thus redetermination of these values from a gas phase Raman spectrum is desirable. Research grade tetrafluorohydrazine was obtained from Air Products and Chemicals Inc. The i.r. spectrum of the gas agreed with those given in the literature[4, 5] and showed no detectable impurities. Samples were sealed into silica cells 45 mm long and 25 mm dia., rounded offat both ends. Prior to filling, the bulbs were seasoned with CIF3 and baked out at 300°C under vacuum overnight. Runs were made on cells filled with initial pressures of ½, l, and 2 atmospheres of N2F4. The Raman apparatus, details of which are published elsewhere[6], included a Coherent Radiation Laboratories *Work performed under the auspices of the U.S. Atomic Energy Commission. 1. C. B. Colburn and F. A. Johnson, J. chem. Phys. 33, 1869 ( 1960); F. A. Johnson and C. B. Colburn. J. Am. chem. Soc. 83, 3043 (1961 ); L. H. Piette, F. A. Johnson, K. A. Booman and C. B. Colburn, J. chem. Phys. 35, 1481 (1961). 2. M. D. Harmony, R. J. Myers, L. J. Schoen, D. R. Lide and D. E. Mann, J. chem. Phys. 35, 1129 (1961). 3. M. D. Harmony and R. J. Myers,J. chem. Phys. 37, 636 (1962). 4. D. F. Koster and F. A. Miller, Spectroehim. A cta 24A, 1487 (1968). 5. J. R. Durig and J. W. Clark, J. chem. Phys. 48, 3216 (1968). 6. H. H. Claassen, G. L. Goodman, J. H. Holloway and H. Selig, J. chem. Phys. 53, 341 (1970).
Notes
Several observations were made for each of the samples and the average results are shown in Table 1, where the Mg to Fe ratio relative to the standard is expressed as a % excess of magnesium. These figures are therefore directly comparable with the parameter x (when this is expressed as a percentage) in the formula (MgO)x • MgFe204 used by Paladino, except that no claim concerning the oxygen content is made in our case. Table !. Mg to Fe ratio relative to equimolar standard Specimen
Magnesium excess(%)
Check sample with 5% Mg excess Check sample with 5% Mg deficiency Sample sintered at 1100"(2 Sample sintered at 1200°C Sample sintered at 1400°C
4'0±0.8 --5"6±1"5 6'9±1"1 5"7±1"0 6-3±1"0
CONCLUSIONS Although our measurements do not reveal information concerning oxygen content, it is clear that the present results are consistent with the earlier conclusions drawn by Paladino. His equilibrium value for x is somewhat higher than the average magnesium excess given here. However, it is noteworthy that within our experimental uncertainty this excess is also independent of sintering temperatures at least up to 1400°C. It is also evident that the present results do not support Reijnen's claim for the existence of stoichiometric MgFe204 spinel, in spite of the fact that we have followed his recommendations concerning preparation.
Department of Physics University of Aston in Birmingham Gosta Green, Birmingham 4 England
T. V I L A I T H O N G * D. C R U M P T O N P.E. FRANCOIS N.W. GRIMES
*On leave from the University of Chiengmai. In receipt of a grant from the British Council.
J. inorg, nucl. Chem., 197 I, Vol. 33, pp. 3166 to 3169.
P~rgamon Press.
Printed in Great Britain
New xanthato nickel complexes (Received 11 February 1971) A XANTHATE ion generally acts as a bidentate ligand in the complexes it forms with transition metals. I.R. studies of these complexes have shown that they may be described by three canonical forms (Fig. 1). Forms b and c, are the nearest of the true electronic structure. These structures, in which the electronic interaction between the sulfurs and the Px nickel orbital is the lowest, are the more favorable
(a)
(b)
Fig. 1.
(c)
Notes
3167
for the formation of adducts with nitrogenous bases. This interaction, which is more marked in the case of dithiocarbamates and especially dithiolates, explains their different behavior towards nitrogenous bases, mainly for dithiolates. On the other hand, study of complexes such as L2Au (dialkyldithiocarbamate)[2] and L2Sn (dialkyldithiocarbamate)2 [3] has shown that an increase in the electron withdrawing character of L. causes a decrease in the contribution of forms b and c (Fig. 1). We have tried to synthetize new xanthate complexes in which the electronic environment of the nickel can be changed by varying the nature of the ligands used, and to study them. For bis(alkylxanthate) nickel we substituted one of the alkylxanthate anions by a halogen atom, and the new complexes thus obtained were stabilized with tertiary phosphine. The formula of the compounds thus obtained is represented in Fig. 2. R_O_..C,~,S~ Ni/X "~S/ Fig. 2.
~pR 3
These compounds are generally synthetized by the reaction between a bis(alkylxanthate) nickel and a nickel halogenide complexed by two molecules of phosphine in a solvent such as diethyl ether or benzene. We have observed that, starting from uncomplexed nickel halogenide, adding phosphine to the reaction medium results in a decrease in the reaction rate in the order I > Br > CI which seems to indicate that the limitative step of the reaction is the formation of the complexe X2Ni(PR3)2. It is interesting to note that sometimes, with nickel methylxanthate as the starting material, derivative of methylthiol are obtained. The reaction of a hydracid with a nickel xanthate together with phosphine in diethyl ether gives products with the same aspect as those obtained in other ways but for which the analysis are not entirely satisfactory. A N M R study of the compounds thus obtained shows the presence of an ethyl group (Hen31"= 7'2 ppm, Hcns'r = 5'02 ppm, Zcn3cn, = 0"13 ppm in the compound G) whose origin can presumably be found in the action of hydracid on diethyl ether. Unfortunately, we are not yet able to fully define the position of this ethyl radical in these complexes. The complexes represented in Fig. 2 are not very stable and cannot be stored long in air. They are soluble in a number of organic solvents in which they are stabilized by an excess of phosphine. The molecular weights measured in acetonitrile indicate that they are slightly dissociated monomeres. Their electronic spectra are characteristic of square planar structures. For instance, the following transitions are observed for iodo (ethylxanthate) (triphenylphosphine) nickei(II) in acetonitrile: JA1o-+1A2o 18,200cm -1 ( e = 2 6 0 ) JAlo--+lBza 21,000cm -1 ( e = 5 4 0 ) JA1o--~IEo 24,100cm -~ (~ = 1200). The diamagnetism of these compounds is consistent with a square planar structure. Small shifts in the C - - O frequency are observed in their i.r. spectra. It is possible that, due to their polarization, the phosphines play a compensating part in the electron withdrawing nature of the halogen. It is interesting to note that some of these complexes seem to form adducts with another molecule of phosphine at low temperature resulting in a pentaccordinated nickel. Complexes with similar structure have already been described [5, 6]. EXPERIMENTAL Bis(alkylxanthate)nickel and dihalogeno bis(phosphine)nickel were prepared by published methods [7, 8]. 1. D. N. Coucouvanis, Ph.D. Thesis, University of Cleveland (1967). 2. H . J . A . Blaauw, R. J. F. Nivard and G. J. M. Van der Kerk, J. organomet. Chem. 2, 236 (1964). 3. M. Honda, M. Komura, Y. Kawasaki, T. Tanaka and R. Okawara, J. inorg, nucl. Chem. 30, 3231 (1968). 4. G. Maki, J. chem. Phys. 29, 162 (1958). 5. D. Walter, G. Wilke, Angew. Chem. 78, 941 (1966). 6. F. Guerrieri and G. P. Chiusolo, J. organomet. Chem. 15,209 (1968). 7. G.W. Watt and B. J. McCormick, J. inorg. Chem. 27,898 (1965). 8. L. M. Venanzi, J. chem. Soc. 719 (1958).
3168
Notes
I.R. Spectra were recorded on a Perkin-Elmer 457, electronic spectra on a Perkin-Elmer 402, N M R spectra by Mr. J. C. Roussel on a Varian A 60.
A. Bromo( ethylxant hate)( triphe nyl phosphine )nickel( l l ) 0"6 of nickel ethylxanthate are dissolved in 100 ml of diethyl ether with good stirring. 1"3 g of nickel bis(triphenylphosphine)bromide are added. The solution becomes red, is stirred during one hour allowed to stand for the night and filtered. The violet crystals are dissolved in 30 ml of benzene containing 0-2 g of triphenylphosphine. The solution is reduced to 10 ml and allowed to crystallize during two days. 1.2 g of violet crystals are collected Pt = 108-109 °. Anal. Calcd. For C2tH~0OSsNiBrP: C, 48"31; H, 3.86; S, 12"28; Ni, 11"24; Br, 15.30; P, 5.93. Found: C, 48.33; H, 3.92; S, 12.13; Ni, 11"39; Br, 15.41; P, 5"77.
B. l odo( ethylxanthate )( triphenylphosphine )nickel( l l ) (a) In the same way as for the bromo derivative A, using nickel bis(triphenylphosphine)iodide, 1"25 g brown crystals are obtained pt = 118-119 °. Anal. Calcd. For C~H~0OS2NilP: C, 44.32; H, 3.54; S, 11"27; Ni, 10"32; I, 22.30; P, 5.44. Found: C, 44"33; H, 3.32; S, 11"76; Ni, 10-76; I, 22"40; P, 5.57. (b) 1-8 g of nickel ethylxanthate are dissolved in 1000 ml of diethyl ether, and 3 g of nickel iodide and 3.15 g of triphenyl phosphine are added while stirring. Stirring is maintained during two days during which time the solution becomes brown. Filtration gives a brown compound which is crystallized from benzene. Ps = 119". Anal. Found: C, 44.03; H, 3"88; S, 11 "38; Ni, 10.43; I, 22"48; P, 5"53.
C. C hloro( ethylxanthate )( triphenylphosphine )nickel( l l ) The same method is used as for the bromo derivative A, starting from nickel bis(triphenylphosphine)chloride; violet crystals (0.95 g) are obtained. Anal. Calcd. For C21H20OS2NiCIP: C, 52-81 ; H, 4.22; S, 13"43; Ni, 12.29; CI, 7.42; P, 6.48. Found: C, 52.64; H, 4.35; S, 13"24; Ni, 12' 11 ; CI, 7.46; P, 6"31.
D. l odo( isopropylxanthate )( triphenylphosphine )nic ke l( l l ) The same method as for the ethylxanthate derivative B(a) is used, starting from nickel isopropylxanthate; brown crystals are obtained (1.15 g). Anal. Calcd. For C22H22OS2NilP: C, 45"31; H, 3.80; S, 11.00; Ni, 10"07; I, 21-76; P, 5"31. Found: C, 45.51; H, 3.74; S, 10.86; Ni, 10"17; I, 21.97; P, 5.23.
E. l odo( ethylxanthate )( triphenylphosphine )nickel( l l ) In the same way as for the triphenylphosphine derivative B(b), using triphenylphosphite, 1.3 g of red brown crystals are obtainedps = 135-136 °. Anal. Calcd. For C21H~004S2NilP: C, 40.89; H, 3'25; S, 10.40; Ni, 9"52; I, 20-57; P, 5.02. Found: C, 40.76; H, 3.27; S, 10.55; Ni, 9.79; I, 20.66; P, 4.94.
F. C hloro( ethylxant hate)( tricyclohexyl phosphine )nickel( l l ) 1 g of nickel ethylxanthate, 2'4 g of tricyclohexylphosphine and 1 g of nickel chloride are dissolved with stirring in 20 ml of dimethoxyethane. The solution is warmed to 80°C and maintained at that temperature during 1 hr and filtered while hot. After standing for 2 days at room temperature, brown crystals are collected and recrystallized from benzene. Anal. Calcd. For CzlHasOS2NiC1P: S, 12.90; Ni, 11"89; C1, 7"16; P, 6.26. Found: S, 13-39; Ni, 12'32; CI, 7.21 ; P, 6.26.
G. Syntheses from hydracid 1 g of nickel methylxanthate are dissolved in 500 ml of diethylether together with 1.55 g of triphenylphosphine. While stirring, a solution of 0.85 ml BrH(d = 1.8) to 5 ml of absolute ethanol is
Notes
3169
added dropwise. The solution becomes red and a small amount of nickel bromide is formed. Stirring is maintained during 1 hr and the solution is filtered. The filtrate is reduced to 200 ml and left to stand for 2 days. 0.6 g of violet crystals are obtained. Anal. Calcd. For C22H2aOS~NiBrP: C, 49-21; H, 4.46; S, 11.88; Ni, 10.95; Br, 14.81; P, 5.76. Found: C, 49.29; H, 3.80; S, 11-87; Ni, 10"95; Br, 14.89; P, 5"62. H. Synthesis o f a thiol derivative The method described for preparing iodo(ethylxanthate)(triphenylphosphine) nickel Ba is used with nickel methylxanthate. Brown crystals are obtained. Anal. Calcd. For C~HIsSNilP: S, 6.48; Ni, 11.92; I, 25"68; P, 6.28. Found: S, 6-74; Ni, 12.21; 1, 26-31; P, 6.40. lnstitut Fran9ais du P~trole BP. 1 8 . 9 2 - R euil-Malmaison France
C. BLEJEAN J. L. C H E N O T
J. inorg,nucI.Chem., 1971.Vol.33, pp. 3169to 3171. PergamonPress. Printedin Great Britain
Raman spectrum of the NF~ radical* (First revived 14 September 1970; in revised form 4 January 1971 ) THE FREE radical NF2 was discovered by Colburn et a/.[1] at the beginning of the last decade. It results from dissociation of tetrafluorohydrazine at elevated temperatures. Several infrared studies of this radical have been reported. A study of the i.r. gas spectrum of NF~ by Harmony et a/.[2] permitted only the definite assignment of the symmetric stretching fundamental v~ at 1074.3 cm -1, although the gas spectrum indicated another band between 930 and 940 cm -~ almost obscured by N2F4 bands. A subsequent matrix isolation i.r. spectrum[3] located this latter band definitely, at 930.7 cm -j, and in addition a very weak band at 573.4 cm -~ which was assigned to the bending mode, vs. We felt it worthwhile to investigate the Raman spectrum of this system, since the totally symmetric bending frequency should be intense and sharp in the Raman spectrum and easily identifiable because it should be strongly polarized. Moreover, frequencies obtained in matrices, are occasionally shifted from the gas values, and thus redetermination of these values from a gas phase Raman spectrum is desirable. Research grade tetrafluorohydrazine was obtained from Air Products and Chemicals Inc. The i.r. spectrum of the gas agreed with those given in the literature[4, 5] and showed no detectable impurities. Samples were sealed into silica cells 45 mm long and 25 mm dia., rounded offat both ends. Prior to filling, the bulbs were seasoned with CIF3 and baked out at 300°C under vacuum overnight. Runs were made on cells filled with initial pressures of ½, l, and 2 atmospheres of N2F4. The Raman apparatus, details of which are published elsewhere[6], included a Coherent Radiation Laboratories *Work performed under the auspices of the U.S. Atomic Energy Commission. 1. C. B. Colburn and F. A. Johnson, J. chem. Phys. 33, 1869 ( 1960); F. A. Johnson and C. B. Colburn. J. Am. chem. Soc. 83, 3043 (1961 ); L. H. Piette, F. A. Johnson, K. A. Booman and C. B. Colburn, J. chem. Phys. 35, 1481 (1961). 2. M. D. Harmony, R. J. Myers, L. J. Schoen, D. R. Lide and D. E. Mann, J. chem. Phys. 35, 1129 (1961). 3. M. D. Harmony and R. J. Myers,J. chem. Phys. 37, 636 (1962). 4. D. F. Koster and F. A. Miller, Spectroehim. A cta 24A, 1487 (1968). 5. J. R. Durig and J. W. Clark, J. chem. Phys. 48, 3216 (1968). 6. H. H. Claassen, G. L. Goodman, J. H. Holloway and H. Selig, J. chem. Phys. 53, 341 (1970).