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PHOSPHORUS-FLUORINE CHEMISTRY, XXXI 8 7 9

Phosphorus-Fluorine Chemistry, X X X I 1

Synthesis and Nuclear Magnetic Resonance Investigation of Methyl-substituted Piperidyl-fluorophosphoranes

M . J. C . HEWSON a n d R . SCHMUTZLER

Lehrstuhl B für Anorganische Chemie der Technischen Universität Braunschweig

(Z. Naturforsch. 27 b, 879—884 [1972] ; received May 26, 1972)

Methvlpiperidyl fluorophosphoranes, dynamic stereochemistry, nuclear magnetic resonance

The preparation of a series of methyl-substituted piperidyl-fluorophosphoranes is described, of general formula RR'NPF4_TCPhn (where RR 'N = 2-Me-piperidyl-, 3-Me-piperidyl-, or 4-Me-piperi-dyl; n = 0, 1, or 2) , from the cleavage of silicon-nitrogen bonds in methyl-substituted piperidyl silanes by fluorophosphoranes. The structures of the new compounds are deduced from 19F and 3 , P n.m.r. data.

The cleavage reactions of silicon-nitrogen bonds in aminosilanes by fluorophosphoranes have proved to be a general method for the preparation of amino-substituted fluorophosphoranes 2' 3. In general these reactions are characterised by monosubstitution as has been observed for the reactions of trimethyl-silyl thioethers with fluorophosphoranes4 but con-trast to reactions of aryltrimethylsilyl ethers with fluorophosphoranes5 which are characterised by multisubstitution.

Further interest has arisen, concerning the pre-paration of fluorophosphoranes containing asymme-tric amino groups, and the compounds thus pre-pared have been shown to have interesting stereo-chemical properties resulting from the restriction of the P — N bond rotation 6' 7. Aminotetrafluorophos-phoranes of the type RNHPF4 (where R = Et, Bul, 2,6-Et2C6H3-, 2,6-Me2C6H3-, 2,4-Me2C6H3- or P r 1 ) 8 ' 9 ; aminotrifluorophosphoranes of the type RR'PFg (where R = Me2N or Et2N; R' = MeNH, Pr'NH or BuNH) 1 0 ; and (RNH)2PF3 (where R = Me, Et or Bu l) 8 ' 9 ; aminodifluorophosphoranes of the type RR'MePF, (where R = MeNH, EtNH or Pr'NH; R' = Et2N, IVNH or C 6HUNH) 11 have been prepared from the reaction of the respective fluoro-phosphoranes with the corresponding amines. A silicon-nitrogen bond cleavage reaction was em-ployed for the preparation of MeNHPF4 12 from the reaction of phosphorus pentafluoride with

Requests for reprints should be sent to Prof. R. SCHMUTZ-LER, Lehrstuhl B für Anorgan. Chemie d. T.U., D-3300 Braunschweig, Pockelsstraße 4.

methylaminotrimethylsilane, MeNHSiMe3 . In all of these compounds the asymmetry is due to the pre-sence of a primary amine group.

Our interest was directed towards the prepara-tion and investigation of aminofluorophosphoranes containing an asymmetric secondary amino group. The compounds investigated were methyl-substituted piperidyl phenyl fluorophosphoranes.

Results and Discussion

We have found that cleavage of the silicon-nitro-gen bond of methyl-substituted piperidyl silanes (1) by fluorophosphoranes proceeds with the formation of trimetylfluorosilane and the corresponding me-thylpiperidyl fluorophosphoranes (2) ,

[ ^ M e + Ph„PF 5 _ n

N SiMe3

1 (n = 0,1 or 2)

o PhnPF 4 -n

Me + Me3SiF

This proved to be no exception to the well docu-mented routes to aminofluorophosphoranes 2' 3,

R» 'PF5 -„ +R 2 NSiMe 3 ^ R2NPF4-nR,/ + Me3SiF

Table I lists the methyl-substituted piperidyl silanes prepared and Table II lists the fluorophosphoranes obtained from them.

The piperidyl-tetra- and tri-fluorophosphoranes are all colourless liquids and the corresponding di-fluorophosphoranes are white crystalline solids. They all show a stability to hydrolysis comparable to other fluorophosphoranes 2.

8 8 0 M. J. C. HEWSON AND R. SCHMUTZLER

Compound Reactants Reaction Yield b. p. Analysis [moles] Conditions [%] [ °C/mm]

hr (temp. °C) C H N Si

2-MeC5H9NSiMe3 2-MeC5H9NH Me3SiCl Et3N Ether

(1.26) (1.26) 12 (reflux) (1.26) (11.)

65 90/66 63.2 63.7

12.3 12.0

8.2 8.1

16.4 16.2

Calc. Found

3-MeC5H9NSiMe3 3-MeC5H9NH Me3SiCl Et3N Ether

(1.3) (1.3) (1.3) (11.)

12 (reflux) 70 108/120 63.2 63.3

12.3 12.6

8.2 8.0

16.4 16.1

Calc. Found

4-MeC5H9NSiMe3 4-MeC5H9NH Me3SiCl Et3N Ether

(1.2) (1-2) (1.2) (11.)

12 (reflux) 67 106/120 63.2 63.0

12.3 12.3

8.2 8.1

16.4 16.3

Calc. Found

Table I. Methyl-substituted piperidyl silanes from the reaction of methyl-substituted piperidines with trimethylchlorosilane.

Compound Reactants (moles)

Reaction Con-ditions [hr./°C]

Yield [%] b. p. [ °C/mm]

C

Analysis

H F N P

2-MeC5H9NPF4 2-MeC5H9NSiMe3 PFS (0.08)

(0.08) 72 ( — 78) 61 54/20 calc. found

35.1 35.0

5.8 5.8

37.1 37.3

3-MeC5H9NPF4 3-MeC5H9NSiMe3 PF5 (0.08)

(0.08) 72 ( — 78) 32 58/20 calc. found

35.1 35.2

5.8 5.8

37.1 37.0

4-MeC5H9NPF4 4-MeC5H9NSiMe3 PF5 (0.06)

(0.06) 72 ( — 78) 57 54/20 calc. found

35.1 35.2

5.8 5.8

37.1 36.6

2-MeC5H9NPF3Ph 2-MeC5H9NSiMe3 PhPF4 (0.05)

(0.05) 1/60 61 85/0.01 calc. found

54.7 56.1

6.4 6.8

3-MeC5H9NPF3Ph 3-MeC5H9NSiMe3 PhPF4 (0.05)

(0.05) 1/60 40 83/0.01 calc. found

54.7 54.7

6.4 6.4

21.6 21.8

11.7 11.3

4-MeC5H9NPF3Ph 4-MeC5H9NSiMe3 PhPF4 (0.08)

(0.08) 1/50 96 82/0.01 calc. found

54.7 54.7

6.4 6.4

21.6 21.6

11.7 11.7

2-MeC5H9NPF2Ph2 2-MeC5H9NSiMe3 Ph2PF3 (0.05)

(0.05) 2.5/80 93 166/0.05 calc. found

67.3 68.7

6.8 7.3

3-MeC5H9NPF2Ph2 3-MeC5H9NSiMe3 Ph2PF3 (0.05)

(0.05) 2.5/80 92 165/0.05 calc. found

67.3 67.7

6.8 6.8

11.8 11.6

4-MeC5H9NPF2Ph2 4-MeC5H9NSiMe3 Ph2PF3 (0.05)

(0.05) 2.5/80 93 165/0.03 calc. found

67.3 67.5

6.8 6.9

11.8 12.0

4.3 4.4

Table II. Methyl-substituted piperidylfluorophosphoranes from the cleavage reaction of piperidyl-A-trimethyl-silanes with fiuorophosphoranes.

The thermal stability of the piperidyl fiuorophos-phoranes is dependent on the number of fluorine atoms present in the molecule. Both the trifluoro-phosphoranes and the tetrafluorophosphoranes show a tendency, under the influence of heat, to rearrange to their ionic isomers in the same fashion as has been observed for other aminofluorophosphora-nes 2 ' 1 3 - 1 5 the rearrangements proceeding according

to the equations,

2 RR'NPF4 [ (RR'N)2PF2] + [PF6]" 16

2RR'NPF 3Ph-> [ (RR'N) 2PFPh]+ [PhPF5] ~ 16

Formation of ionic products was also observed upon prolonged standing of the samples but if stored at low temperatures the compounds could be kept for indefinite periods. In contrast, the piperidyl difluoro-

PHOSPHORUS-FLUORINE CHEMISTRY, XXXI 881

phosphoranes show no tendency to decompose or rearrange even on heating for long periods.

All the compounds prepared were characterised by 19F and 31P n.m.r. spectroscopy and by elemental analysis.

Nuclear Magnetic Resonance Data

Table III lists room temperature 31P n.m.r. data for the various compounds, TablesIV and Y list the room temperature and low temperature 19F n.m.r. data obtained for the tetrafluorophosphoranes, tri-and di-fluorophosphoranes, respectively.

Compound (5 P. JPF Multipli-[p.p.m.p [Hz] city

2-MeC5H9NPF4 (2 a) +70.6 846 quintet 3-MeC5H9NPF4 (2 b) +72.2 849 quintet 4-MeC5H9NPF4 (2 c) +72.4 856 quintet 2-MeC5H9NPF3Ph (3 a) +53.5 815 (ax)e doublet of 2-MeC5H9NPF3Ph (3 a)

960 (eq) triplets 3-MeC5H9NPF3Ph (3 b) + 55.0 825 (ax) doublet of 3-MeC5H9NPF3Ph (3 b)

955 (eq) triplets 4-MeC5H9NPF3Ph (3 c) + 55.6 820(ax) doublet of 4-MeC5H9NPF3Ph (3 c)

965 (eq) triplets 2-MeC5H9NPF»Ph2 (4 a) d + 51.8 712 triplet 3-MeC5H9NPF„Ph2 (4 b) d + 51.7 708 triplet 4-MeC5H9NPF2Ph2 (4 c) d +55.1 715 triplet

Table III. Room temperature 31P n.m.r. data for methyl-sub-stituted piperidyl fluorophosphoranes a .

a All values refer to neat liquids. b Phosphorus chemical shifts measured relative to 85% H3P04 as external standard. c ax-, eq- = axial, equatorial. d Spectra run on sample as super-

cooled liquid.

The room temperature 31P n.m.r. data are con-sistent with trigonal bipyramidal geometry in every case in which the amino group and the phenyl groups occupy equatorial s i tes 2 ' 1 7 . Interesting features are seen in the 19F n.m.r. spectra.

As has been observed for mercapto-substituted tetrafluorophosphoranes4 the piperidyl tetrafluoro-phosphoranes undergo a positional exchange of axial and equatorial fluorine atoms. Consequently, the room temperature 19F n.m.r. spectra of these com-pounds show a simple doublet instead of more com-plicated spectra which wTould be expected for a rigid molecule. This "pseudorotation" process is common in mono-substituted fluorophosphoranes, and is thought to occur in the parent compound, phospho-rus pentafluoride, as well 1 8 _ 2 ° . However, as has been observed for diorganoaminotetrafluorophos-phoranes, R 2NPF 4 1 8 , 1 9 on cooling to below

Compound Temp. [°C]

J [Hz] <5F [p.p. .M.] B

2-MeC5H9NPF4 + 30 JPF 8 4 6 (5F (average) + 66.9

(2 a) - 1 0 0 JPF5 921 (5F3 + 72 .2 (in JPF4 9 0 5 <5F4 + 7 4 . 2 toluene) JPF1 781 8F1 + 60 .3

JPF* 7 8 1 ÖF2 + 60.3 JF'F4 51 JF'F1 74 JF'F1 67

3-MeC5H9NPF4 + 30 JPF 8 4 9 <5F (average) + 67 .8

(2 b) - 1 0 0 JPF' 9 4 0 <5F3 + 72.1 (in JPF4 9 4 0 <5F4 + 7 4 . 0 toluene) JPF1 7 6 3 ÖF1 + 60 .2

JPF' 7 6 3 <5F2 + 60 .2 JF'F4 50 JF'F1 77 JF'F1 63

4-MeC5H9NPF4 + 3 0 ° JPF 8 6 5 <5F (average) (2 c) + 67 .6

Table IV. 19F n.m.r. data for methylpiperidyltetrafluorophos-phoranes a .

a F1 and F2 refer to the axial fluorine atoms: F3 and F4 refer to the equatorial fluorine atoms. b Fluorine chemical shifts were measured relative to CC13F as internal standard. c Due to viscosity problems no adequate low temperature spectrum

could be obtained.

— 60 °C, the rate of positional exchange is slowed down sufficiently, relative to the n.m.r. time scale, to permit the observation of distinct axial and equa-torial fluorine environments. The axial fluorine atoms are characterised by low chemical shifts, rela-tive to CC13F, and the equatorial fluorine atoms are characterised by high chemical shifts.

The piperidyl tetrafluorophosphoranes, 2-methyl-piperidyltetrafluorophosphorane (2 a) and 3-methyl-piperidyltetrafluorophosphorane (2 b) , however, show another change, quite distinct from the "freez-ing" of pseudorotation, as the temperature is lowered. This change appears to be due to the hin-drance of free rotation about the P —N bond, and it is manifest in non-equivalence of the two equa-torial fluorine atoms in the low temperature spectra of these compounds 21. In contrast, the low tempera-ture spectrum of 4-methyl-piperidyltetrafluorophos-phorane (2 c ) indicates magnetically equivalent fluorine atoms, independent of the temperature.

A similar phenomenon is also observed for the piperidyl-di- and tri-fluorophosphoranes that we have investigated21. The room temperature 19F n.m.r. spectra of 2-, 3- and 4-methyl-piperidyl-

8 8 2 M. J. C. HEWSON AND R. SCHMUTZLER

Compound Temp. t°C]

J 1Hz] <3F[p.p.m.l

2-MeC5H9NPF3Ph + 30 JPF1 828 dF1 + 42.6 (3 a) Jp r- 814 (5F2 + 44.3 (3 a)

JPF® 965 ÖF3 + 67.8 JF'F2 14 JF'F3 55 JF2F' 55

3-MeC5H9NPF3Ph + 30 JPF1 823 ÖF1 + 43.4 (3 b) JPFS 820 <3F2 + 43.7 (3 b)

JPF3 1066 <5F3 + 69.1 JF'F2 14 JF'F5 55 JF=F5 55

4-MeC5H9NPF3Ph + 30 JPF1 820 5F1 + 43.5 (3 c) JPF2 820 <5F2 + 43.5 (3 c)

JPF3 965 <5F3 + 68.1 JF'F2 0 JF'F3 56 JF2FS 56

- 9 0 No significant spectral (in change was observed. toluene)

2-MeC5H9NPFoPh2 + 30 JPF 712 8F + 37.9 (4 a) - 7 0 JPF1 689 8F1 + 34.6 (4 a)

(in JPF2 689 ÖF2 + 36.8 toluene) JF'F2 14

3 -MeC5H9NPF2Ph2 + 30 JPF 708 6F + 37.6 (4 b) (in toluene)

- 7 0 (c) (in ether)

4-MeC5H9NPF2Ph2 + 3 0 JPF 715 ÖF + 38.1 (4 c) (in toluene)

- 7 0 (in toluene)

No significant spectral change was observed.

Table V. 1!,F n.m.r. data for methylpiperidyl-tri- and di-fluorophosphoranes a .

F1 and F2 refer to the axial fluorine atoms: F3 refers to the single equatorial fluorine atom. b Fluorine chemical shifts were measured relative to CC13F as internal standard. c No adequate low temperature spectrum could be obtained but collapse of the room temperature doublet indicates magnetic

non-equivalence of the two axial fluorine atoms.

difluorophosphorane also show a simple doublet. On cooling below — 60 °C this doublet disappears, and in the case of 2- and 3-methyl-piperidyldifluoro-phosphorane (4 a and 4 b ) one observes a.b. sub-spectra 22, suggesting magnetic non-equivalence of the axial fluorine atoms, F1 and F 2 ; for 4-methyl-piperidyldifluorophosphorane (4 c ) no significant spectral change is observed between room tempera-ture and — 70 °C. This observation is consistent with the axial fluorine atoms, F1 and F2 remaining magnetically equivalent over a wide range of tem-perature.

The room temperature spectra of 2- and 3-methyl-piperidyltrifluorophosphorane, (3 a and 3 b ) , indi-cate three different fluorine atom environments, the axial fluorine atoms, F1 and F2 , being magnetically non-equivalent, while in the spectrum of 4-methvl-piperidyltrifluorophosphorane (3 c) , even on cooling to — 90 °C, only two fluorine atom environments are apparent.

The observations made for the di- and tri-fluoro-phosphoranes can also be explained by the rate of rotation about the P — N bonds being within the time scale of the n.m.r. measurements.

We therefore suggest, in the light of this evidence, that the observed non-equivalence of either axial or equatorial fluorine atoms, as reflected in the 19F n.m.r. spectra, for these methylpiperidylfluorophos-phoranes, is due to the slowing down of the free rotation about the phosphorus-nitrogen bond, with respect to the n.m.r. time scale. It is further sug-gested that the piperidyl ring will take the position of least stereochemical hindrance, this being in the equatorial plane for the tetrafluorophosphoranes (2,

12; n =0)

Me

MG

f2

y i > x

• \ i 2 . - x >N-P<.

(3; n =1,X=Ph)

(4 ; n =2, X=Ph)

Fig. 1. Suggested structures for methyl-substituted piperidyl-fluorophosphoranes showing the apparent orientation of the piperidyl ring, relative to the trigonal-bipyramidal framework

of the fluorophosphorane.

n = 0) and the axial plane for the tri- and di-fluoro-phosphoranes (3, n = 1, 4, = 2 ) . Fig. 1 shows the proposed structures for the compounds prepared. It can be clearly seen that the position of the methyl groups on the piperidyl ring influences the environ ments of the axial or equatorial fluorine atoms.

From the results obtained for 2- and 3-methyl-piperidylfluorophosphoranes one can, by analogy, assume that the structures of the 4-methylpiperidvl-

PHOSPHORUS-FLUORINE CHEMISTRY, XXXI 8 8 3

V I PF,

V " I PFQPh

\ / K N PF2Ph2

4

R1 R2 R3

H H Me

H Me H

Me H H

b;

Fig. 2. Explanation of substituent positions in methyl-substi-tuted piperidyl fluorophosphoranes.

fluorophosphoranes are similar, although because of the symmetrical nature of the 4-methylpiperidyl group the axial or equatorial fluorine atoms remain magnetically equivalent.

Although the observed 19F room temperature spectra of 2-methyl- and 3-methyl-piperidyltrifluoro-phosphoranes show magnetically non-equivalent axial fluorine atoms, the 31P n.m.r. spectra show no extra peaks due to the non-equivalence of the fluorine atoms. This observation might be explained from the fact that the chemical shift difference be-tween the two axial fluorine atoms is small in com-parison to the large chemical shift difference be-tween phosphorus and fluorine, and that the 31P n.m.r. resonance lines are probably too broad, due to nitrogen quadrupole relaxation, for any extra spin-spin coupling to be observed.

Experimental

The usual precautions required in handling moisture-sensitive phosphorus compounds were observed.

31P and 19F n.m.r. spectra were obtained on a Varian Associates 60 Mc/sec HA 60 spectrometer, fitted with an external frequency generator to enable measurement of 19F n.m.r. spectra by wide lode techni-que. Sealed capillaries containing 85% phosphoric acid solution were used as an external reference for the phosphorus spectra, and fluorotrichloromethane was used as an internal standard in all of the 19F n.m.r. spectra. All low temperature spectra were run in toluene solution.

The methyl-substituted piperidyl silanes were pre-pared from the reaction of trimethylchlorosilane with the respective methyl piperidyl compounds in the presence of triethylamine as acid acceptor. After sepa-ration of the amine hydrochloride the filtrates were distilled under vacuum, affording the iV-trimethylsilyl compounds as colourless liquids in high yields. Table I lists the compounds prepared.

Preparation of methyl-substituted piperidylfluoro-phosphoranes

The following examples of the syntheses of tetra-, tri- and di-fluorophosphoranes illustrate the procedures used in the preparation of all the methyl-substituted piperidylfluorophosphoranes. In all cases the amount of trimethylfluorosilane formed was determined and this invariably corresponded to a quantitative or nearly quantitative yield, assuming the cleavage of one P —F bond per molecule of the original fluorophosphorane.

2-Methylpiperidyltetrafluorophosphorane

Phosphorus pentafluoride (9.5 g; 0.08 mole) was condensed onto 2-methylpiperidyltrimethylsilane (12.9 g; 0.08 mole) in vacuo in a glass reaction tube at —196 °C. The tube was sealed and left to stand in a bath at — 78 °C for three days. The tube was then opened, trimethylfluorosilane was allowed to eva-porate at room temperature, and the remaining liquid was distilled under reduced pressure from a 25 ml. flask. 2-Methylpiperidyltetrafluorophosphorane (10.1 g; 61%) was obtained as a colourless liquid of b. p. 54 °C/20 mm. The liquid was transferred to a Teflon vial and stored at low temperature.

2-Methylpiperidylphenyltrifluorophosphorane

2-Methylpiperidyltrimethylsilane (8.5 g; 0.05 mole) was added dropwise, with stirring, to phenyltetra-fluorophosphorane (9.2 g; 0.05 mole) at 50 °C. An exothermic reaction was observed, the temperature rising to about 60 °C. After the mixture had been heated at 60 °C for 0.5 h. the reaction appeared to be complete. A total of 3.6 g (79%) of gas was collected in a —78 °C trap and was identified as trimethylfluoro-silane. Distillation of the residue in vacuo yielded 2-methylpiperidylphenyltrifluorophosphorane (8.2 g; 61%) b. p. 86 °C/0.01 mm as a colourless, mobile liquid.

2-Methylpiperidyldiphenyldi fluorophosphorane

2-Methylpiperidyltrimethylsilane (8.5 g; 0.05 mole) was added, with stirring, to diphenyltrifluorophospho-rane (12.2 g; 0.05 mole) at 50 °C. An exothermic reaction was observed, the temperature rising to about 60 °C. The mixture was heated at 80 °C for 2 h and a volatile product was collected in a trap at — 78 °C. This was identified as trimethylfluorosilane (4.3 g; 93%). Distillation of the residue in vacuo yielded 2-methylpiperidyldiphenyldifluorophosphorane (14.7 g; 93%) b. p. 166°C/0.05 mm as a colourless oil which subsequently solidified. The compound was further purified by sublimation at 100 °C/0.03 mm using a water-cooled probe, and affording white needle-like crystals.

We are indebted to Dr. R. SCHLIEBS and Prof. H. HOFFMANN of Farbenfabriken Bayer A.G. for some organophosphorus intermediates employed in this work.

884 F. HOLSBOER UND W. BECK

Prof. H. JONAS of Farbenfabriken Bayer A.G., Lever-kusen, is thanked for generous samples of trimethyl-chlorosilane. M. J. C. HEWSON acknowledges a main-

1 For Part XXX in this series, see: W. STADELMANN, O. STELZER, and R. SCHMUTZLER, Z. anorg. allg. Chem. 385, 142 [1971].

2 R. SCHMUTZLER, in: Halogen Chemistry, vol. 2, p. 31, (ed. V. GUTMANN) , Academic Press, London, New York 1967.

3 a) R. SCHMUTZLER, Angew. Chem. 76, 893 [1964] ; Angew. Chem. Internat. Edne. 3, 753 [1964]. b) G. C. DEMITRAS and A. G. MCDIARMID, Inorg. Chem. 6, 1903 [1967].

4 S . C . PEAKE a n d R . S C H M U T Z L E R , J . c h e m . S o c . [ L o n d o n ] (A) 1970, 1049.

5 S . C . PEAKE, M . F I L D , M . J . C . H E W S O N , a n d R . S C H M U T Z -LER, Inorg. Chem. 10, 2723 [1971].

6 R . SCHMUTZLER and G. S. REDDY, Inorg. Chem. 4, 191 [1965].

7 M . A . L A N D A U , V . V . SHELUCHENKO, G . I . D R O Z D , S . S . DUBOV, and S. Z. IVIN, Zhur. Strukt. Khim. 8, 1097 [1967].

8 J . S . H A R M A N a n d D . W . A . S H A R P , J . d i e m . S o c . [ L o n -don] (A) 1970, 1138.

9 J . J . HARRIS a n d B . R U D N E R , J . o r g . C h e m i s t r y 3 3 , 1 3 9 2 [1968].

1 0 G . I . D R O Z D , M . A . SOKAL'SKII , M . A . L A N D A U , a n d S . Z . IVIN, Zhur. obshchei Khim. 39, 1888 [1969].

tenance grant from Deutsche Forschungsgemeinschaft. Finally, support through Fonds der Chemischen Indu-strie is gratefully acknowledged.

1 1 G . I . D R O Z D , S . Z . IVIN, M . A . L A N D A U , a n d V . V . SHELUCHENKO, Zhur. obshchei Khim. 38, 1654 [1968].

12 J. S. HARMAN and D. W . A . SHARP, Inorg. Chem. 10, 1538 [1971].

1 3 G . S . R E D D Y a n d R . SCHMUTZLER, I n o r g . C h e m . 5 , 1 6 4 [1966].

14 R. SCHMUTZLER, J. Amer. diem. Soc. 86, 4500 [1964]. 15 R. SCHMUTZLER, J. chem. Soc. [London] 1965, 5630. 1 6 M . J . C . H E W S O N , S . C . PEAKE, a n d R . S C H M U T Z L E R , u n -

published results. 1 7 J . F . N I X O N a n d R . SCHMUTZLER, S p e c t r o c h i m . A c t a 2 0 .

1 8 3 5 [ 1 9 6 4 ] . 1 8 E . L . MUETTERTIES, W . M A H L E R , K . J . P A C K E R , a n d R .

SCHMUTZLER, Inorg. Chem. 3, 1298 [1964]. 1 9 F . N . TEBBE a n d E . L . MUETTERTIES, I n o r g . C h e m . 7 , 1 7 2

[ 1 9 6 8 ] . 20 R. S. BERRY, J. chem. Physics 32, 933 [I960]. 2 1 M . J . C . H E W S O N , S . C . PEAKE, a n d R . S C H M U T Z L E R , C h e m .

Comm. 1971, 1454. 2 2 J . W . EMSLEY, J . FEENEY, a n d L . H . SUTCLIFFE, " H i g h R e -

solution Nuclear Magnetic Resonance Spectroscopy", vol. 1, p. 310, Pergamon Press, 1967.

Röntgenphotoelektronenspektroskopische Untersuchungen an einigen planaren Pseudohalogeno-d8-Übergangsmetallkomplexen *

X-ray Photoelectron Spectra of Some Planar Pseudohalogeno-d8-Transition

Metal Complexes

F . H O L S B O E R u n d W . BECK

Institut für Anorganische Chemie der Universität München

(Z. Naturforsdi. 27 b, 884—887 [1972] ; eingegangen am 26. Mai 1972)

X-ray photoelectron spectra, pseudohalide complexes of gold (III), linkage isomerism Core binding energies of metals in the isomeric (Ph3As) 2Pd (NCS) 2 and (Ph3As) 2Pd (SCN) 2 ,

and in [AsPhJ [AuX4] (X = CN", tetrazolate, Cl", N3~) are reported. S- and N-Bonding mode can be distinguished in accord with semiemperical MO-calculations. XPS-results are correlated with M ö ß b a u e r spectra and the metal-cyanide and metal-tetrazolate bonds are discussed.

Mit Hilfe der Röntgenphotoelektronenspektrosko-pie1 können die Ionisierungsenergien von Elektro-nen innerer Schalen direkt gemessen werden. Da diese Energien in erster Linie von der Elektronen-dichte an den untersuchten Atomen abhängen, hat sich diese Technik als wertvolles physikalisches Hilfsmittel zur Aufklärung der Bindungsverhältnisse

Sonderdruckanforderungen an Prof. Dr. W. BECK, Institut für Anorganische Chemie der Universität München, D-8000 München 2, Meiserstr. 1.

u. a. auch von Metallkomplexen2 erwiesen. Im fol-genden berichten wir über einige XPS-Untersuchun-gen an quadratisch-planaren Pseudohalogeno-d8-Metallkomplexen und vergleichen sie mit den Er-gebnissen aus der M ö ß b a u e r - Spektroskopie, der Röntgenstrukturanalyse und quantenmechanischen Nährungsverfahren.

* XVVI. Mitt. über Spektroskopische Untersuchungen an Komplexverbindungen; XV. Mitt. R. SCHLODDER, S. VOG-LER u. W. BECK, Z. Naturforsch. 27 b, 463 [1962].