- Email: [email protected]
Methyl group replacement on pentamethylantimony with organophosphorus substituents
233
Journal of Organomeiallic Ckemisby, 150 (1578) 233-237 0 Elsevier Sequoia S-A., Lausanne - Priited in The Netherlands
METHYL GROUP REPLACEMENT ON PENTAMETHYLANTIMONY ORGANOPHOSPHORUS SUBSTITUENTS
GUY E. GRAVES
and JOHN R. VAN WAZER
Department of Chemistry,
WITH
*
Vanderbilt University, Nashville, Tennessee 37235
(U.S.A.)
(Received April 4th, 1977)
Phosphinic and phosphonic acids were treated with pentamethylantimony one of its methyl groups (with formation of methane) to give the following new compounds: (CH,),SbOP(O)(C,H,),, (CH,),SbOP(O)(OH)CH,, and (CH,),SbOP(O)(OH)C,H,. The latter two.compounds are associated, presumably through hydrogen bonding.
to replace
Introduction The chemistry of trivalent organoantimony compounds is much more extensive than the chemistry of the pentavalent organoantimony compounds containing five antimony-carbon bonds El]_ Wittig and co-workers first reported the latter type of compound with the preparation of pentaphenylantimony [2,3] and pentamethylantimony [4]. Additional derivatives include pentaalkyl compounds containing unsaturated organic groups [ 5-101, pentaethylantimony ill], and various mixed methylethyl organoantimony compounds [2]. The chemistry of pentamethyl&imony has received virtually no attention except for the series of papers by Schmidbaur and co-workers [ 13-191. The present article describes the results of our work in replacing methyl groups on pentamethylantimony with organophosphorus substituents. In this presentation we have not speculated about the reaction mechanisms; however mechanisms of somewhat related reactions of pentaphenylantimony have been reported [ 20-231. Experimental Pentamethylantimony [4] and methylphosphonic acid [24] were prepared according to the literature_ Phenylphosphonic and diphenylphosphinic acids were obtained from Aldrich. Cblorodiphenylphosphine was purchased from Alfa Venfron.
TABLE
1
ELEMENTAL
ANALYSES
AND
Compound
PHYSICAL
43.33
by osmometry
in
P
H
5.70
(5.82) 5.51 (5.35)
30.54
Yield (5)
398
(7.76) (30.S) 11.16 43.80 (11.19) 9.07 (9.14)
MO1 S.-k0
M-P.
ec,
(Found caled.)
6b
7.69
(48.16) (5.66) 21.92 5.90 (21.69) 35.29 (35.43)
-
(calcd.)(Z))
Analysis@xmd
C
a Run
CONSTANTS
(43.97) 35.80 (35.92)
(399) 668 (276) 720 (338)
83
150-156
74
145-148
94
204-205
GHc13.
Microanalyses were carried out by Galbraith Laboratories, Inc., Knoxville, Tennessee. Melting points were determined in open capillaries on a Mel-Temp apparatus &rd are uncorrected_ The ‘H nuclear magnetic resonance (NMR) spectra were run on a JEOLCO JNM-MD-100 spectrometer in CDCIS and are referenced to tetramethylsihme (7 10 ppm) as an internal standard. The 31P 6JMR measurements were carried out using a Varian XL-100-15 spectrometer equipped with Fourier-transform accessories supplied by Nicolet Technology Corporation. The spectra were run in CH,C& with broad-band proton decoupling. The chemical shifts were referenced to 85% H3P04 by the tube-interchange method, with negative shifts being downfield. The compounds were prepared in a similar manner and are white solids. A typical preparation was as follows. Synthesis of (CH&3bOP(O)(C&& Pentamethylantimony (0.239 g, 1.17 mmol) was weighed into a nitrogenfilled flask. The flask was then cooled to -78°C in a dry-ice/acetone bath. Di-
TABLE
2
NUCLE*xR
MAkNETIC
Conpouad
RESONANCE
DATA
a (r. ppm)
‘N
6<31P)
T(Sb-CH;) (CH3WbOP(O)(C~H5)2 (CH3)4SbOP(O)(OH)CH3 (CHg)qSbOP(O)(OH)CgHg
8.55 (s) 12H 8.51 (s) 12H 8.55 (s) 12H
8.82 (d. J 16 Hz) 3H -
2.32 (m) 2.78 (m) 2.30 (m) 2.58 (m) 5H
a Abbrevikions: s = singlet. d = doublet. m = multipfet. H = relative number integration. Negative 3IP shifts are downfield from 85% H3P04.
-13.48 -18.92
-8.87
of hydrogens
found
by
235
phenylphosphinio
acid (0.250
g, 1.15
mmol)
was added to the flask along with
about two ml of dried dichloromethane. The reaction flask was allowed to warm slowly under a nitrogen atmosphere. Upon reaching room temperature, gas evolution was noted by the presence of bubbles rising through the solution. After allowing the reaction mixture to.remain at room temperature overnight, the solvent was stripped from the clear, colorless solution to give a white solid identified as (CH&SbOP(0)(C6H& (yield 0.383 g, 83%). Physical properties for the new compounds are listed in Table 1, while spectral properties are given in Table 2.
Results and discussion The room-temperature reaction of diphenylphosphinid acid with pentamethylantimony went as shown in eq. 1 with no evidence for any higher substituted Sb(CH,),
+ (C,H,),P(O)OH
+ (CH,),SbOP(O)(C,H&
+ CH,
(1)
products. Heating a 5/l ratio of diphenylphosphinic acid to pentamethylantimony in a sealed tube at 100°C for 72 h again resulted in the monosubstituted product only as evidenced by ‘H NMR. The proton NMR of the product showed a single peak in the methyl region downfield from the resonance for Sb(CH,),. Although one might expect more than one peak due to the methyl groups being in different environments, this is not the case. Even at -lOO%, Sb(CH,)S is reported to have only a single peak in CS, [25], while the previously described tetramethylantimony derivatives also exhibited just a single peak [13-B]. This equivalence of the four methyl groups was attributed to ligand reorganization (pseudorotation) processes, an argument that probably applies to the new compound also. The interaction of methyl- and phenyl-phosphonic acids with pentamethylantimony gave white crystalline &lids. According to elemental analyses and cryoscopic molecular weight determinations, a product of type I was obtained
(eq. 2) with n being 2.1 to 2.5. The ‘H NMR spectrum exhibited a single peak Sb(CH&
+ RP(O)(OH),
+= [(CH,),SbO&L)OH],
+ CH,
(2)
(I) (R = C,H,,
CH,)
for the antimony
methyl groups, while integration
established
a ratio of four
antimony methyls to one phosphorus phenyl or methyl group. In all phosphorus compounds containing=P(O)(OH) and -P(O)(OH), groups, association through H bonding is almost certain to occur in organic solvents not exhibiting hydrogen bonding 1261. This association has been reported for lqifluoromethylphosphonous acid (dimer)
[27]
and phenylphosphonic
acid (high order of association)
[28] and is almost certainly present in our new compounds. The “P NMR spectra for the three new compounds discussed above exhibited a single sharp peak upfield from the parent acid. The upfield shift increases from the parent phosphoric acids ranged from 1.47 to 5G33ppm. The reaction of pentamethylantimony with chlorodiphenylphosphine was
-_236:1
:
-.
..
ekp&t& ~‘&oceed with the elimination’of.methyl chloride (eq. 3), as previously. .fomid in the-case of methyl phosphorus -[28,23].and ars&nic compdunds [31]_
_ Sb(CH,),i~(C,H,~~P-CI.~
(CE&bP(C,H,), +-&--l&l . ~~ .. (3) _ .. :- -... However, %&pears th&‘the following reaction took place in meth$fene &lo&de with precipitation of the tetramethylstibonium chloride (eq. 4). Sb(CH&
t (C,H,),PCl
+ (CH,),Sb’Cl__ i- (C,H,),PCH,
(4)
The ‘H NMR spectrum of the reaction product gave a doublet (J 5 Hz) at T 1.62 ppm corresponding to T 1.51 ppm (J 6 Hz), as reported for (C,H,),PCH, [32]; and the ‘lP measurements yielded a single peak at -1-26.2 ppm, as compared to a literature value of +28 ppm [33]_ The tetramethylstibonium chloride was identified by elemental analysis_ Acknowledgements We wish to thank the National Science ‘Foundation for partial support of this work under Grant CHE76-04287. References 1 2 3 4 5 6 7 8 9 10 11 12 13 14
15 16 17 18
G_O_ Doak.&d L_D_ Freedman. Organometallic Compounds of Arsenic. Adimon~. and Bismuth. Wiley-Interscknce. New York. 1970. Chapters VII and VIII. G. W&and 5. Claus. dustus Lieb&s Ann. Chem.. 677 (1952) 26. G. mttig and D. rdeElainge1. Chim. Ber.. 97 (1964) 789. G. F&tti.g and K. Tonell. Act+ Chem. Stand., 7 (1953) 1293. A-N_ Nesmeyanov. A-E. Borisov and N.V. Novikova. Izv. Akad. Nauk.SSSR. Otd. Khim- N2uk. <1961) 3.578. A.N.Nesmeyano~. A.E. Borisov and N.V. Novikova, Izv. Akad. Nauk SSSR. Otd. EQdm. Nauk. (1960) 952. A-Ii_ Nesmeyanov. A-R. Bdhov and N.V. Novikova. Izv. Akad. Nauk SSSR. Otd. Khim. N&L&. (19 61) 612; A-N. Nermemov. AX_ Borisov and N.V. Novikova. Izv. Akad. Nauk SSSR. Otd. Kbim- Nauk. <1961) 730. ASI. Nesmeyanov. A.E. Borisov and N-V. Novikove. Izv. Akad. Nauk SSSR. Otd. Khim. Nauk. (1950) 147. A-N. Nesmeyanov, A_% Bolisov and N.V. Novigova, Tetahedron X.&t., (1960) 23. Y. Takashi, J_ Organomefa?. Chem.. 8 (1967) 225. HA_ Meimema and J_G_ Noltes. J. Organometal. Chem.. 22 (1970) 653. H_ Schmidbaur, 3. Weidlein and K.-H. Mitschke, Chem. Ber., 102 (1969) 4136. H. Schmid?xur. K.-H. Mitschke. J. Weidlein and St. Cradock. 2. Anor&!. Aug. Clxem.. 386 <1971) 139. H. Scbmidbatu, EL S&midbaur
K--H- ?&schke,and J. Wtidlein. Z. Anor% Al& Chem.. and K--H_ _Mitschke. t&em_ Ber_. 104 (1971). 1837.
386 (1971)
147.
H:Schmidbaur and K.-H. Mifschke. Chem. Ber.. 104 (1971) 1842. H.-X. Mie. W. Buchner, R. Stiibler and J. Weiaein. Chem. Ber.. 106 (1973) H. uchmidbaur, c 1226. 19 H. Schmidbaur and H.-H- bfitschke. Angew. Chem. Int. Ed. Eng.. 10 (1971) 136. Wikholm. CT. Lin and W-E. McEwen, J. Organomehf. Chem.. 85 (1975) 179. 20 G-F. Laxmea&~~;J. 3 (1974) 229. 21 W-E:. McEwen and CT. L%n. Phosphorus, S.&t_. 42 (1966) 5191. 22 G-EL Briles and W-EL McEwen..Tetzahedxon Amer. Chem. Sot.. 91(1969) 1283. ‘23 K.-W. Shen, W.E. McEwen and A.P. wolf,J_ 3. Amer. Che& Sot.. 75 (1953) 3379. 24 P;C. Crofts and G.&Xi gosolapoff. W. i%Qlz~x~ ILJ. Packer and R. Schmufzler. Iuorg. Chem.. 3 (1964) 1298. 25 E.L. Muetterties. The Structural Chemistry of.~os~horus. Elsetier. New York. 1970. P. 247. 26 D_Y_:.C_ CorI&dge. 4333. 27 A.33. B-.zcg and J-E. Griftiths. J. Amer. Chem. Sot.. 83.(1961) and J.S. Powell. J. C&m. Sot.. (i950) 3635. 28 GJL Kos&poff
237 29 30 31 32 33
K-M. K&f_ RX& I&L S.O.
Abreham Abraham Abraham GelIagber. Gzim. D.A.
and J.R. van Wazer. Phosphorus. 6 (1975) 23. and J_R_ van Wazer. Inorg. C&em_, 14 (1975) 1099. and JJL. van Wazer. J. Organometel. Chem.. 113 (1976) 265. Aust. J. Chem,, 21 (1968) 1197. Wheatland and W. McFarlane. J. Amer. Chem. SOL. 89 (1967)
5573.
Journal of Organomeiallic Ckemisby, 150 (1578) 233-237 0 Elsevier Sequoia S-A., Lausanne - Priited in The Netherlands
METHYL GROUP REPLACEMENT ON PENTAMETHYLANTIMONY ORGANOPHOSPHORUS SUBSTITUENTS
GUY E. GRAVES
and JOHN R. VAN WAZER
Department of Chemistry,
WITH
*
Vanderbilt University, Nashville, Tennessee 37235
(U.S.A.)
(Received April 4th, 1977)
Phosphinic and phosphonic acids were treated with pentamethylantimony one of its methyl groups (with formation of methane) to give the following new compounds: (CH,),SbOP(O)(C,H,),, (CH,),SbOP(O)(OH)CH,, and (CH,),SbOP(O)(OH)C,H,. The latter two.compounds are associated, presumably through hydrogen bonding.
to replace
Introduction The chemistry of trivalent organoantimony compounds is much more extensive than the chemistry of the pentavalent organoantimony compounds containing five antimony-carbon bonds El]_ Wittig and co-workers first reported the latter type of compound with the preparation of pentaphenylantimony [2,3] and pentamethylantimony [4]. Additional derivatives include pentaalkyl compounds containing unsaturated organic groups [ 5-101, pentaethylantimony ill], and various mixed methylethyl organoantimony compounds [2]. The chemistry of pentamethyl&imony has received virtually no attention except for the series of papers by Schmidbaur and co-workers [ 13-191. The present article describes the results of our work in replacing methyl groups on pentamethylantimony with organophosphorus substituents. In this presentation we have not speculated about the reaction mechanisms; however mechanisms of somewhat related reactions of pentaphenylantimony have been reported [ 20-231. Experimental Pentamethylantimony [4] and methylphosphonic acid [24] were prepared according to the literature_ Phenylphosphonic and diphenylphosphinic acids were obtained from Aldrich. Cblorodiphenylphosphine was purchased from Alfa Venfron.
TABLE
1
ELEMENTAL
ANALYSES
AND
Compound
PHYSICAL
43.33
by osmometry
in
P
H
5.70
(5.82) 5.51 (5.35)
30.54
Yield (5)
398
(7.76) (30.S) 11.16 43.80 (11.19) 9.07 (9.14)
MO1 S.-k0
M-P.
ec,
(Found caled.)
6b
7.69
(48.16) (5.66) 21.92 5.90 (21.69) 35.29 (35.43)
-
(calcd.)(Z))
Analysis@xmd
C
a Run
CONSTANTS
(43.97) 35.80 (35.92)
(399) 668 (276) 720 (338)
83
150-156
74
145-148
94
204-205
GHc13.
Microanalyses were carried out by Galbraith Laboratories, Inc., Knoxville, Tennessee. Melting points were determined in open capillaries on a Mel-Temp apparatus &rd are uncorrected_ The ‘H nuclear magnetic resonance (NMR) spectra were run on a JEOLCO JNM-MD-100 spectrometer in CDCIS and are referenced to tetramethylsihme (7 10 ppm) as an internal standard. The 31P 6JMR measurements were carried out using a Varian XL-100-15 spectrometer equipped with Fourier-transform accessories supplied by Nicolet Technology Corporation. The spectra were run in CH,C& with broad-band proton decoupling. The chemical shifts were referenced to 85% H3P04 by the tube-interchange method, with negative shifts being downfield. The compounds were prepared in a similar manner and are white solids. A typical preparation was as follows. Synthesis of (CH&3bOP(O)(C&& Pentamethylantimony (0.239 g, 1.17 mmol) was weighed into a nitrogenfilled flask. The flask was then cooled to -78°C in a dry-ice/acetone bath. Di-
TABLE
2
NUCLE*xR
MAkNETIC
Conpouad
RESONANCE
DATA
a (r. ppm)
‘N
6<31P)
T(Sb-CH;) (CH3WbOP(O)(C~H5)2 (CH3)4SbOP(O)(OH)CH3 (CHg)qSbOP(O)(OH)CgHg
8.55 (s) 12H 8.51 (s) 12H 8.55 (s) 12H
8.82 (d. J 16 Hz) 3H -
2.32 (m) 2.78 (m) 2.30 (m) 2.58 (m) 5H
a Abbrevikions: s = singlet. d = doublet. m = multipfet. H = relative number integration. Negative 3IP shifts are downfield from 85% H3P04.
-13.48 -18.92
-8.87
of hydrogens
found
by
235
phenylphosphinio
acid (0.250
g, 1.15
mmol)
was added to the flask along with
about two ml of dried dichloromethane. The reaction flask was allowed to warm slowly under a nitrogen atmosphere. Upon reaching room temperature, gas evolution was noted by the presence of bubbles rising through the solution. After allowing the reaction mixture to.remain at room temperature overnight, the solvent was stripped from the clear, colorless solution to give a white solid identified as (CH&SbOP(0)(C6H& (yield 0.383 g, 83%). Physical properties for the new compounds are listed in Table 1, while spectral properties are given in Table 2.
Results and discussion The room-temperature reaction of diphenylphosphinid acid with pentamethylantimony went as shown in eq. 1 with no evidence for any higher substituted Sb(CH,),
+ (C,H,),P(O)OH
+ (CH,),SbOP(O)(C,H&
+ CH,
(1)
products. Heating a 5/l ratio of diphenylphosphinic acid to pentamethylantimony in a sealed tube at 100°C for 72 h again resulted in the monosubstituted product only as evidenced by ‘H NMR. The proton NMR of the product showed a single peak in the methyl region downfield from the resonance for Sb(CH,),. Although one might expect more than one peak due to the methyl groups being in different environments, this is not the case. Even at -lOO%, Sb(CH,)S is reported to have only a single peak in CS, [25], while the previously described tetramethylantimony derivatives also exhibited just a single peak [13-B]. This equivalence of the four methyl groups was attributed to ligand reorganization (pseudorotation) processes, an argument that probably applies to the new compound also. The interaction of methyl- and phenyl-phosphonic acids with pentamethylantimony gave white crystalline &lids. According to elemental analyses and cryoscopic molecular weight determinations, a product of type I was obtained
(eq. 2) with n being 2.1 to 2.5. The ‘H NMR spectrum exhibited a single peak Sb(CH&
+ RP(O)(OH),
+= [(CH,),SbO&L)OH],
+ CH,
(2)
(I) (R = C,H,,
CH,)
for the antimony
methyl groups, while integration
established
a ratio of four
antimony methyls to one phosphorus phenyl or methyl group. In all phosphorus compounds containing=P(O)(OH) and -P(O)(OH), groups, association through H bonding is almost certain to occur in organic solvents not exhibiting hydrogen bonding 1261. This association has been reported for lqifluoromethylphosphonous acid (dimer)
[27]
and phenylphosphonic
acid (high order of association)
[28] and is almost certainly present in our new compounds. The “P NMR spectra for the three new compounds discussed above exhibited a single sharp peak upfield from the parent acid. The upfield shift increases from the parent phosphoric acids ranged from 1.47 to 5G33ppm. The reaction of pentamethylantimony with chlorodiphenylphosphine was
-_236:1
:
-.
..
ekp&t& ~‘&oceed with the elimination’of.methyl chloride (eq. 3), as previously. .fomid in the-case of methyl phosphorus -[28,23].and ars&nic compdunds [31]_
_ Sb(CH,),i~(C,H,~~P-CI.~
(CE&bP(C,H,), +-&--l&l . ~~ .. (3) _ .. :- -... However, %&pears th&‘the following reaction took place in meth$fene &lo&de with precipitation of the tetramethylstibonium chloride (eq. 4). Sb(CH&
t (C,H,),PCl
+ (CH,),Sb’Cl__ i- (C,H,),PCH,
(4)
The ‘H NMR spectrum of the reaction product gave a doublet (J 5 Hz) at T 1.62 ppm corresponding to T 1.51 ppm (J 6 Hz), as reported for (C,H,),PCH, [32]; and the ‘lP measurements yielded a single peak at -1-26.2 ppm, as compared to a literature value of +28 ppm [33]_ The tetramethylstibonium chloride was identified by elemental analysis_ Acknowledgements We wish to thank the National Science ‘Foundation for partial support of this work under Grant CHE76-04287. References 1 2 3 4 5 6 7 8 9 10 11 12 13 14
15 16 17 18
G_O_ Doak.&d L_D_ Freedman. Organometallic Compounds of Arsenic. Adimon~. and Bismuth. Wiley-Interscknce. New York. 1970. Chapters VII and VIII. G. W&and 5. Claus. dustus Lieb&s Ann. Chem.. 677 (1952) 26. G. mttig and D. rdeElainge1. Chim. Ber.. 97 (1964) 789. G. F&tti.g and K. Tonell. Act+ Chem. Stand., 7 (1953) 1293. A-N_ Nesmeyanov. A-E. Borisov and N.V. Novikova. Izv. Akad. Nauk.SSSR. Otd. Khim- N2uk. <1961) 3.578. A.N.Nesmeyano~. A.E. Borisov and N.V. Novikova, Izv. Akad. Nauk SSSR. Otd. EQdm. Nauk. (1960) 952. A-Ii_ Nesmeyanov. A-R. Bdhov and N.V. Novikova. Izv. Akad. Nauk SSSR. Otd. Khim. N&L&. (19 61) 612; A-N. Nermemov. AX_ Borisov and N.V. Novikova. Izv. Akad. Nauk SSSR. Otd. Kbim- Nauk. <1961) 730. ASI. Nesmeyanov. A.E. Borisov and N-V. Novikove. Izv. Akad. Nauk SSSR. Otd. Khim. Nauk. (1950) 147. A-N. Nesmeyanov, A_% Bolisov and N.V. Novigova, Tetahedron X.&t., (1960) 23. Y. Takashi, J_ Organomefa?. Chem.. 8 (1967) 225. HA_ Meimema and J_G_ Noltes. J. Organometal. Chem.. 22 (1970) 653. H_ Schmidbaur, 3. Weidlein and K.-H. Mitschke, Chem. Ber., 102 (1969) 4136. H. Schmid?xur. K.-H. Mitschke. J. Weidlein and St. Cradock. 2. Anor&!. Aug. Clxem.. 386 <1971) 139. H. Scbmidbatu, EL S&midbaur
K--H- ?&schke,and J. Wtidlein. Z. Anor% Al& Chem.. and K--H_ _Mitschke. t&em_ Ber_. 104 (1971). 1837.
386 (1971)
147.
H:Schmidbaur and K.-H. Mifschke. Chem. Ber.. 104 (1971) 1842. H.-X. Mie. W. Buchner, R. Stiibler and J. Weiaein. Chem. Ber.. 106 (1973) H. uchmidbaur, c 1226. 19 H. Schmidbaur and H.-H- bfitschke. Angew. Chem. Int. Ed. Eng.. 10 (1971) 136. Wikholm. CT. Lin and W-E. McEwen, J. Organomehf. Chem.. 85 (1975) 179. 20 G-F. Laxmea&~~;J. 3 (1974) 229. 21 W-E:. McEwen and CT. L%n. Phosphorus, S.&t_. 42 (1966) 5191. 22 G-EL Briles and W-EL McEwen..Tetzahedxon Amer. Chem. Sot.. 91(1969) 1283. ‘23 K.-W. Shen, W.E. McEwen and A.P. wolf,J_ 3. Amer. Che& Sot.. 75 (1953) 3379. 24 P;C. Crofts and G.&Xi gosolapoff. W. i%Qlz~x~ ILJ. Packer and R. Schmufzler. Iuorg. Chem.. 3 (1964) 1298. 25 E.L. Muetterties. The Structural Chemistry of.~os~horus. Elsetier. New York. 1970. P. 247. 26 D_Y_:.C_ CorI&dge. 4333. 27 A.33. B-.zcg and J-E. Griftiths. J. Amer. Chem. Sot.. 83.(1961) and J.S. Powell. J. C&m. Sot.. (i950) 3635. 28 GJL Kos&poff
237 29 30 31 32 33
K-M. K&f_ RX& I&L S.O.
Abreham Abraham Abraham GelIagber. Gzim. D.A.
and J.R. van Wazer. Phosphorus. 6 (1975) 23. and J_R_ van Wazer. Inorg. C&em_, 14 (1975) 1099. and JJL. van Wazer. J. Organometel. Chem.. 113 (1976) 265. Aust. J. Chem,, 21 (1968) 1197. Wheatland and W. McFarlane. J. Amer. Chem. SOL. 89 (1967)
5573.