Phosphonium bis(glycolates) and phosphinoglycolates: Synthesis, solvolysis, oxidation to (thio)phosphinoylglycolates and use as ligands in Ni-catalyzed ethylene oligomerization

Article abstract of DOI:10.1016/j.poly.2012.04.019

Secondary phosphines, glyoxylic acid hydrate and amines react to form organoammonium phosphonium bis(glycolates) 1a-d. In CD₃OD solution, diphenylphosphonium bis(glycolates) undergo reversible solvolysis to phosphinoglycolates 2a,b and acetalic glyoxylic species. The P-dialkyl species 1c avoids this and maintains the phosphonium bis(glycolate) structure in CD ₃OD (cHex₂P) or undergoes further solvolysis with partial formation of R₂PH (R = tBu). Condensation to phosphinoglycines, e.g. 3b, observed for primary amines, does not take place with N-secondary amines at room temperature. Heating leads to condensation but is followed by decarboxylation as shown for the conversion of 2a to 4a. Because of the kinetic lability, the phosphonium compounds 1a-d are sensitive to oxidation by air, H₂O₂, or sulfur. The resulting phosphinoyl and thiophosphinoyl glycolates and glycolic acids 5-8 are kinetically stable. Precatalyst solutions formed from 1a, c, d and Ni(COD)₂ in THF developed moderate to good activity in the oligo- or polymerization of ethylene to linear products containing methyl and vinyl end groups. Activity and molecular weights increased with the +I-effect of the P-substitutents. The solution structures of the novel compounds were elucidated by multinuclear NMR spectroscopy. For 7a a crystal structure analysis is also presented.

Full text of DOI:10.1016/j.poly.2012.04.019

Polyhedron 41 (2012) 61–69
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Polyhedron
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Phosphonium bis(glycolates) and phosphinoglycolates: Synthesis, solvolysis,
oxidation to (thio)phosphinoylglycolates and use as ligands in Ni-catalyzed
ethylene oligomerization
Normen Peulecke a,b, Markus K. Kindermann a, Martin Köckerling c, Joachim Heinicke a,
⇑
a Institut für Biochemie, Ernst-Moritz-Arndt-Universität Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
b Leibniz-Institut für Katalyse e. V. an der Universität Rostock, Albert-Einstein-Str. 29a, D-18059 Rostock, Germany1
c Anorganische Festkörperchemie, Universität Rostock, Albert-Einstein-Str. 3a, D-18051 Rostock, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
Secondary phosphines, glyoxylic acid hydrate and amines react to form organoammonium phosphonium
bis(glycolates) 1a–d. In CD3OD solution, diphenylphosphonium bis(glycolates) undergo reversible solvol-
ysis to phosphinoglycolates 2a,b and acetalic glyoxylic species. The P-dialkyl species 1c avoids this and
maintains the phosphonium bis(glycolate) structure in CD3OD (cHex2P) or undergoes further solvolysis
with partial formation of R2PH (R = tBu). Condensation to phosphinoglycines, e.g. 3b, observed for pri-
mary amines, does not take place with N-secondary amines at room temperature. Heating leads to con-
densation but is followed by decarboxylation as shown for the conversion of 2a to 4a. Because of the
kinetic lability, the phosphonium compounds 1a–d are sensitive to oxidation by air, H2O2, or sulfur.
The resulting phosphinoyl and thiophosphinoyl glycolates and glycolic acids 5–8 are kinetically stable.
Precatalyst solutions formed from 1a, c, d and Ni(COD)2 in THF developed moderate to good activity in
the oligo- or polymerization of ethylene to linear products containing methyl and vinyl end groups. Activ-
ity and molecular weights increased with the +I-effect of the P-substitutents. The solution structures of
the novel compounds were elucidated by multinuclear NMR spectroscopy. For 7a a crystal structure anal-
ysis is also presented.
Received 29 February 2012
Accepted 17 April 2012
Available online 4 May 2012
Dedicated to Prof. P.G. Jones on the occasion
of his 60th birthday
Keywords:
Phosphine
Phosphonium
P,O Ligand
Three-component synthesis
Nickel
Ethylene oligomerization
Ó 2012 Elsevier Ltd. All rights reserved.
1. Introduction
of
[10], which extend the research of other groups on synthetic phos-
phino amino acids with the phosphino group in b- or -position or
a-phosphino amino acids [9], in particular phosphinoglycines
Addition reactions of phosphines or phosphine oxides to alde-
hydes or ketones have long been studied [1,2] but the behaviour to-
c
at a phenyl group [11–13]. For our one-pot synthesis of N-mono-
substituted phosphinoglycines from primary amines, diphenyl-
phosphine and glyoxylic acid hydrate, monitoring by NMR gave
evidence of a stepwise condensation via organoammonium phos-
phinoglycolates. In reactions with secondary amines the second
step was not observed. With N-methylaniline the corresponding
diphenylphosphinoglycolate salt was isolated [10c], whereas in
the reaction of diethylamine with dicyclohexylphosphine and gly-
oxylic acid hydrate (despite a 1:1:1 M ratio) diethylammonium
dicyclohexylphosphoniumbis(glycolate) (1a) was obtained [10a].
This hints at a more complicated reaction behavior and prompted
us to investigate such conversions as well as the properties and se-
lected reactions of organoammonium phosphoniumbis- and phos-
phino-glycolates in more detail. Because of the close structural
relationship of the phosphino glycolates with phosphino acetic
acids [14], which are industrially used as catalyst ligands in the
first step of the Shell Higher Olefin Process [15], the applicability
as ligands in the nickel catalyzed ethylene oligomerization was
also investigated.
wards
a-ketocarboxylic acids has attracted little attention.
Concerning phosphines, to our knowledge only the condensation
of 1-adamantylphosphine with two equivalents of glyoxylic acid
to AdaP(CHOH-COOH)2 has been reported [3]. More important was
the reaction of the secondary phosphine oxide Me2PHO with glyoxy-
lic acid, which afforded the potent herbicide Me2P(O)CH(OH)COOH
(Hoe704) [4,5]. Dimethylthiophosphinoylglycolic acid was synthe-
sized analogously from Me2P(S)H and glyoxylic acid and structurally
characterized by X-ray crystallography [6]. Finally, by reaction of
secondary phosphine oxides or sulfides with pyruvic or benzoylfor-
mic acid or their esters, other types of 2-phosphinoyl 2-hydroxy-
carboxylic acids or their esters have also been obtained [7]. The
latter also allowed kinetic resolution of enantiomers by lipases [8].
Our studies of the reactions of phosphines with glyoxylic acid
are part of broader investigations on the synthesis and reactivity
⇑
Corresponding author. Fax: +49 3834 864377.
E-mail address: heinicke@uni-greifswald.de (J. Heinicke).
Present address.
1
0277-5387/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.poly.2012.04.019

62
N. Peulecke et al. / Polyhedron 41 (2012) 61–69
Scheme 1. Formation and solvolysis of phosphonium bis(glycolates) and phosphinoglycolates.
decarboxylation, leading to the formation of the known [16] diethyl-
2. Result and discussion
aminomethylphosphine 4a.
To evaluate if primary alkylamines, which form N-monosubsti-
tuted phosphinoglycines in the 1:1:1 three-component reaction
with diphenylphosphine and glyoxylic acid hydrate in diethyl
ether [10a–c], are able to provide phosphoniumbis(glycolates),
the behavior of N-tert-butyl-diphenylphosphinoglycine (3b) to-
wards glyoxylic acid hydrate was studied. On dissolution of 3b in
D2O, solvolysis to 2b (d 6.7 ppm) was observed. Stronger dilution
with water or aqueous NaOH(D) caused further decomposition
with formation of Ph2PH and Ph2PD. The addition of small amounts
of acetic acid, which binds the tert-butylammonium cations as ace-
tate, led to the appearance of the signals of 1b, i.e. phosphorus sig-
nals for two pairs of diastereoisomers and two PCHO proton and
carbon doublets, which is indicative for the phosphoniumbis(gly-
colate). A quantitative conversion of 3b to 1b was observed in
D2O solution by addition of an equimolar amount of glyoxylic acid
hydrate. The NMR spectra of the white precipitate, measured in
D2O solution, indicated pure 1b. In analogy to 1a, in CD3OD, a sol-
volysis equilibrium of 1b with formation of monoglycolate 2b, gly-
oxylic acid CD3OH-semiacetale and smaller amounts of 3b along
with partial decarboxylation to 4b were observed (d 31P 27.2,
26.1; 7.4, 3.1, À19.9 ppm; rel. int. 8:6:60:14:12%).
2.1. Phosphoniumbis(glycolates) and phosphinoglycolates
Our investigations began with the three component reaction of
diphenylphosphine and diethylamine with glyoxylic acid hydrate
in diethyl ether in a 1:1:1 M ratio. A few minutes after combining
the solutions a white precipitate was formed. Elemental analyses
and NMR spectra provided evidence that the product is the phos-
phoniumbis(glycolate) 1a (yield 47%). When the synthesis was re-
peated in a 1:1:2 M ratio the yield of 1a was improved to 70%. NMR
spectra measured in D2O confirmed the phosphoniumbis(glyco-
late) structure by two phosphorus resonances in the range of phos-
phonium signals (d 27.7, 27.5 ppm) and two PCH doublets in the
proton and 13C NMR spectra. This was evidence of formation of
both of the two diastereoisomer pairs, rac and meso, caused by
the two asymmetric P-CH(OH) carbon centers. NMR spectra in
CD3OD, however, indicated solvolysis with formation of phosphi-
noglycolate 2a and glyoxylic acid semiacetale (Scheme 1). Because
crystallization of 1a from a concentrated methanol solution still
lead to the isolation of 1a, the solvolysis must be an equilibrium
reaction. This indicates that 2a reacts with glyoxylic acid methanol
semiacetale back to 1a when the latter precipitates after exceeding
its solubility. The phosphinoglycolate 2a was obtained in high yield
and with satisfying elemental analyses by reaction of the oil
formed from glyoxylic acid and diethylamine in diethyl ether2 with
diphenylphosphine in THF. X-ray diffraction of crystals of 2a con-
firmed the diethylammonium phosphino glycolate nature but poor
crystallinity prevented sufficient refinement (R1 ca. 14%) to afford
detailed data. In solution the structure was confirmed by 31P, 13C
and 1H NMR spectra. In contrast to 1a, which decomposed in at-
tempts to prepare CDCl3 solutions by warming, 2a was sufficiently
soluble in this solvent to allow for measuring without interference
by solvolysis reactions. Compound 2a displayed the phosphorus res-
onance at d 6.2 ppm and conclusive proton and 13C doublets for
PCHOH in the OCH signal range. In D2O and CD3OD solutions, how-
ever, signals due to solvolysis equilibria were observed. Attempts to
achieve conversion of 2a to the N,N-disubstituted diphenylphosphi-
noglycin 3a by thermally induced condensation failed due to facile
In addition to diphenylphosphine, dicyclohexyl- and di-tert-
butylphosphine were also used in this study to evaluate the behav-
ior of the more P-basic dialkylphosphines to this condensation. The
reactions with diethylamine and glyoxylic acid hydrate (molar ra-
tios ca. 1:1:1) proceeded analogous to the above conversions, and
instead of monoglycolates, they furnished phosphinobis(glyco-
lates) 1c and 1d; these were identified by elemental analysis and
solution NMR spectra. The solution of 1c in D2O and also in CD3OD
displayed the signals characteristic for the rac/meso bis(glycolates).
Only a trace of the solvolysis product 2c was observed in CD3OD.
The bulky di-tert-butylphosphine derivative 1d was sufficiently
soluble in CDCl3 to allow for characterization by solution NMR
spectra but suffered from partial decomposition to tBu2PH and gly-
oxylic acid derivatives and was labile in D2O or CD3OD solution. In
these solvents mixtures were formed including large amounts of
tBu2PH. The monoglycolate 2d was prepared in an inverse proce-
dure with addition of tBu2PH to a THF solution of diethylammo-
nium glyoxylate (molar ratio ca. 1:1:1, 10% excess of Et2NH).
Product separation with extraction by diethyl ether lead to a prod-
uct that could be conclusively characterized by NMR in CDCl3
2
Proton and carbon NMR spectra indicate formation of diethylammonium
glyoxylate hydrate along with small signals of a labile hemiaminal (see supplemen-
tary data).

N. Peulecke et al. / Polyhedron 41 (2012) 61–69
63
solution. This compound also underwent major solvolysis in
CD3OD with formation of large amounts of tBu2PH.
In summary, the solution NMR spectra show that (i) both, phos-
phoniumbis(glycolates) 1 and phosphinoglycolates 2, are kineti-
cally labile towards protic solvents, (ii) compounds 2 are less
stable in D2O than 1 and shift the equilibrium towards 1 and (iii)
the dialkylphosphinoglycolates 2c,d are less stable in CD3OD than
the diphenylglycolates 2a,b and thus form either only trace
amounts of phosphinoglycolate, e.g. 2c, or tend to undergo further
solvolysis with partial formation of secondary phosphine, e.g. in
the case of 2d.
Scheme
thiophosphinoylglycolates.
3. Alternative
synthesis
of
phosphinoylglycolates
and
2.2. Phosphinoylglycolates
Phosphonium salts are usually air stable. However, because of
the solvolysis equilibrium with 2, solutions of 1 were attacked by
air and gave mixtures of products. Pure diphenylphosphinoylgly-
colates 5a–d were obtained by oxidation of 1a–d with aqueous
H2O2. The free diphenylphosphinoylglycolic acids 6ab,c,d were
then liberated by treatment of 5a–d with H+-charged cation ex-
changer (Amberlyst-15Ò) (Scheme 2). The oxidation by sulfur
was studied for 1a and 1b in methanolic solution, which furnished
thiophosphinoylglycolate 7a and 7b, and treatment with H+-
charged cation exchanger gave for both the same free thiophosphi-
noylglycolic acid 8ab. The (thio)phosphinoylglycolates and -gly-
colic acids were much more stable to hydrolysis than their
counterparts with three-valent phosphorus.
The organoammonium phosphinoylglycolates 5a–d and the
phosphinoylglycolic acids 6ab,c,d were also synthesized indepen-
dently by reaction of the respective phosphine oxides and glyoxylic
acid hydrate in ethereal solution at room temperature with and
without the amine, respectively (Scheme 3). Condensation with
the amines to phosphinoylglycines, i.e. Kabachnik–Fields-reaction
[17], was not observed under these mild conditions. The mass
spectrum of 5d after thermal volatilization on the push rod
(130 °C) of the mass spectrometer provided evidence of a ther-
mally induced replacement of the hydroxyl by the diethylamino
group. The peak with the highest mass fits with expected m/z-ratio
of tBu2PCH@NEt2+ and is consistent with loss of CO2 of a thermally
labile phosphinoylglycine.
Fig. 1. Molecular structure of 7a in the crystal (thermal ellipsoids at the 50%
probability level). Selected bond lengths (Å) and angles (°): P1–C1 1.862(1), P1–C3
1.812(1), P1–C9 1.815(1), P1–S1 1.9500(4), C1–O1 1.409(1), C1–C2 1.537(1), C2–O2
1.238(2), C2–O3 1.248(2); C3–P1–C9 103.24(5), C3–P1–C1 108.47(5), C3–P1–S1
114.45(4), C9–P1–S1 112.71(4), C1–P1–S1 112.71(4), O1–C1–C2 112.16(10), O1–
C1–P1 108.48(7), C2–C1–P1 109.51(7).
assignment of the carbon NMR data (except some superimposed
cyclohexyl signals), which displayed characteristic 13C NMR chem-
ical shifts for the P-substituents and different position-dependent
P–C coupling constants for phosphines, phosphonium compounds,
phosphine oxides and phosphine sulfides [18]. Thus, the PCHN
signals of 4a and 3b appeared at d 57.89 (d, 1J = 2.7 Hz) and d
1
58.3 (d, JPC = 12.2 Hz) [10a], respectively. On the other hand, the
PCHO signals of the phosphoniumbis(glycolates) 1a,c,d (d 66–69
(d, 1J = 33–57 Hz)), phosphinoglycolates 2a,b (d 71–74 (d, 1J = 23–
25 Hz)), phosphinoylglycolates 5a–d (d 68–74 (d, 1J = 65–82 Hz))
and thiophosphinoylglycolates 7 (d 74–75 (d, 1J = 58–60 Hz)) were
observed at lower field with one-bond P-C coupling constants
2.3. Structure elucidation
The structures of the products were confirmed by satisfactory
elemental analyses, conclusive NMR data, and for 7a by Xray crys-
tal structure analysis (Fig. 1). Several compounds form hydrates,
which may be attributed to hydrogen bonds to the carboxylate
and/or the hydroxyl group. The structures of 1 in D2O and 2 in
CD3OD or CDCl3 solution and the solution structures of the
kinetically stable compounds 4–8 were elucidated chiefly by the
1
increasing in the order JPC(2a,b) < 1JPC(1c) < 1JPC(1d) < 1JPC(1a) <
1JPC(7a,b) < 1JPC(5d) 6 1JPC(5c) < 1JPC(5b) 6 1JPC(5a). Similarly, the
PCHO proton signals of these compounds are downfield shifted (d
4.44–6.00) compared to the PCHN-signals of 4a or 3b (d 3.27,
2
4.12 [10a]) but the JPH coupling values are angle dependent and
unsuitable to distinguish the various compound types. The easiest
Scheme 2. Formation of (thio)phosphinoylglycolates and (thio)phosphinoylglycolic acids.

64
N. Peulecke et al. / Polyhedron 41 (2012) 61–69
Fig. 2. Packing of the ions of 7a in the crystal. Dashed lines mark the shortest intermolecular contacts.
way to assign the different Ph2P compound types presented here is
provided by the phosphorus resonance, which appeared increas-
ingly downfield shifted in the order 4a (d À26.4) < 3b (d
3.4) < 2a,b (d 6.7) < 1a,b (d 27.5–27.7) < 5a,b (d in CDCl3 31–33,
in D2O 37–38) < 7a,b (d 45.8–47.4). This allowed for the evaluation
of the above discussed equilibrium reactions (see Section 2.1.). For
the dicyclohexyl- (1c (d 31–32) < 5c (d in CDCl3 52.6–55.2, in D2O
57.7)) and the di-tert-butyl phosphorus compounds (2d (d
30.1) 6 1d (d 30–39) < 5d (d in CDCl3 61)) the trend is similarly
but the differences vary and limit the diagnostic value of the phos-
phorus resonance compared to the PCHO carbon doublet.
products of the ethylene conversion (Table 1) were mainly lower
-olefins in the case of the Ni/1a catalyst and linear polymers for
a
Ni/1c and Ni/1d. The molecular weights increased with the +I-ef-
fect of the P-substituents, just as it was observed in earlier screen-
ing tests of 2-phosphinophenolate/Ni catalysts with varying
P-substituents [19]. The high selectivity for linear products with
vinyl and methyl end group hints at an oligo/polymerization mech-
anisms in analogy to that discussed for nickel phosphinoacetate,
-enolate or -phenolate catalysts with chain start via a NiH species
and chain growth termination by b-hydride elimination [15,19].
More detailed structure information was obtained for 7a by
crystal structure analysis (Figs. 1 and 2). The bond lengths and
angles display usual values. The hydroxyl group forms an intramo-
lecular hydrogen bond to the O2 atom of the carboxyl unit at an
O1–H1BÁ Á ÁO2 distance of 2.526 Å (O1–H distance fixed at 0.82 Å),
fixing it in a syn-conformation to the OH group. Further intermo-
lecular OÁ Á ÁH contacts exist at distances of 2.680 Å and NÁ Á ÁH
contacts at 2.059 and 2.374 Å. The packing of ions in crystals of
7a is depicted in Fig. 2, which shows the intermolecular contacts
as dashed lines. Along the crystallographic a-direction all the
P-connected phenyl rings are aligned parallel to each other.
3. Conclusion
Secondary phosphines, glyoxylic acid hydrate and amines react
in the aprotic polar solvent diethyl ether at room temperature with
precipitation of organoammonium phosphonium bis(glycolates),
even in a 1:1:1 M ratio. These compounds are observed also in
D2O solution as clean compounds and hydrolyze only on strong
dilution. Surprisingly, in CD3OD the solutions of diphenylphospho-
nium bis(glycolates) 1a,b display reversible solvolysis with forma-
tion of diphenylphosphinoglycolates and acetalic glyoxylic acid
species. This behavior hints at an energy controlled balance of sol-
vated phosphonium compounds versus phosphinoglycolates and
MeO(HO)CHCOOH. The dialkylphosphonium bis(glycolates) exhi-
bit lower tendency to form phosphinoglycolates in CD3OD and
either show preferably the NMR signals of the starting material
(1c) or extended solvolysis with partial formation of secondary
phosphine (tBu2PH from 1d). The higher P-donor strength of the
dicyclohexylphosphino- compared to the diphenylphosphinogly-
colate may disfavor the transfer of the second glycolate group to
methanol as a competing O donor whereas 1d may be sterically
destabilized with two glycolate in addition to two bulky tert-butyl
groups at phosphorus. The low barrier for the transfer of the
(HO)C+H-COOÀ M H+–O@CH–COOÀ substituent to O-donor sol-
vents makes the solutions of phosphonium bis(glycolates) suscep-
tible to oxidation and electrophiles. In combination with the good
storability of dry solid phosphonium bis(glycolates) (under nitro-
gen for years) they are suitable as precursors for the synthesis of
2.4. Tests for applicability
The close structural relationship of the phosphinoglycolates 2
with phosphinoacetic acids [14], used as ligands in nickel P^OÀ
chelate catalysts for ethylene oligomerization [15], and the easy
conversion of 1 to 2 inspired us to test if phosphonium bis(glyco-
lates) 1a–d and Ni(1,5-COD) form in situ catalysts for batch oligo-
merization of ethylene. The reactions were carried out at 100 °C
(starting pressure 30–50 bar, Table 1) in THF, which was found
suitable in the screening of catalysts formed in situ from 3b or re-
lated phosphinoglycines and Ni(COD)2 [10a–d]. The catalysts gen-
erated with phosphonium bis(glycolates) 1a, 1c and 1d gave
moderate to good conversion, increasing with the +I-effect of the
P-substituents. However, 1b did not form a catalyst under these
conditions. No pressure decrease was observed in this case. The

N. Peulecke et al. / Polyhedron 41 (2012) 61–69
65
Table 1
Screening of ethylene oligomerization catalysts formed in situ from 1a–d, Ni(COD)2 in THFa.
e
Entry
Catalyst
mol)
Ethylene (g, mol); Conversion (%);b
TON (mol/mol)
Cond. butenes (g); oligomers
in flash dist. (Cx wt.%)c
Polymer;d mp. (°C);
MNMR (g/mol)
%Vin/olefin; Me/Vin;
Me/1000 Ce
(
l
d (g/cm3)
1
1a/Ni (120, 120)
10.0 (0.356); 44; 1307
C4 (22), C6 (34), C8 (28),
C10 (14), C12 (2)
traces
1.3 g wax
n.d.
n.d.
2
3
1c/Ni (104, 110)
1d/Ni (102, 106)
7.3 (0.260); 59; 1476
12.6 (0.449); 75; 3303
4.3 g PE; 124–6; 0.96
9.3 g PE; 129–132; 0.96
1900
5350
>99:1; 1.2;9.4
97:3; 1.2; 3.1
traces
a
Starting pressure 30–50 bar, heating to 100 °C (bath) for 15 h. A blind experiment showed that Ni(COD)2 or Ni(COD)2 in THF without phosphonium glycolate did not
convert ethylene. 1b did not form an active catalyst.
b
Conversion of C2H4 by mass difference after releasing unconverted ethylene.
Relative content of linear a-olefins Cx estimated from GC for assumption of mass proportional sensitivity of the FID.
c
d
e
Polymer purified with aqueous methanolic hydrochloric acid.
By 1H NMR after swelling for 1d at 100 °C in C6D5Br and measuring at 100 °C.
kinetically stable phosphinoyl- or thiophosphinoyl glycolates or of
complexes which, even if they are not isolable as defined species,
may be useful as catalysts.
Found: C, 58.91; H, 6.72; N, 3.28%. 1H NMR and CH-COSY
(D2O): d = 1.19 (t, 3J = 7.3 Hz, 6H, CH3), 2.99 (q, 3J = 7.3 Hz,
2
6H, N+CH2), 5.84 (d, JPH = 7.3 Hz, 1H, PCHA), 6.00 (d,
2JPH = 7.7 Hz, 1H, PCHB), 7.53–7.65 (m, 4H, H-m), 7.68–7.82
(m, 5H, 3H-o, 2H-p), 7.85–7.94 (m, 1H, H-o); N+H and OH
of solvent 4.72. 13C NMR and CH-COSY (D2O): d = 10.27
(CH3), 41.98, 42.08 (NCH2), 68.99 (d, 1J = 56.6 Hz, PCHA),
69.70 (d, 1J = 51.3 Hz, PCHB), 114.93 (d, 1J = 78.9 Hz, Cq-i),
115.13 (d, 1J = 77.8 Hz, Cq-i), 115.51 (d, 1J = 79.2 Hz, Cq-i),
129.01 (d, 3J = 12.0 Hz, CH-m), 129.11 (d, 3J = 11.9 Hz, CH-
m), 129.21 (d, 3J = 12.1 Hz, CH-m), 133.89 (d, 2J = 8.4 Hz,
CH-o), 134.00 (d, 2J = 8.3 Hz, CH-o), 134.26 (d, 2J = 8.2 Hz,
CH-o), 134.39 (d, 4J = 3.0 Hz, CH-p), 134.46 (d, 4J = 3 Hz,
CH-p), 170.74 (COO–). 31P{1H} NMR (D2O): d = 27.7, 27.5
(rac/meso ca. 1:1); after storage two additional small signals
d = 27.61, 27.46, relative intensity increasing with the time,
attributed to CH-CD exchange.
4. Experimental
4.1. General remarks
All operations were conducted under nitrogen atmosphere by
using Schlenk techniques and freshly distilled dry solvents. Ph2PH,
Cy2PH and tBu2PH were prepared via the corresponding chloro-
phosphines and reduction with LiAlH4 in diethyl ether [20]. Gly-
oxylic acid monohydrate, the amines, Ni(COD)2 and ethylene
(99.5%, Air Liquide) were used as purchased. NMR solvents were
recondensed before use, CDCl3 after drying with P4O10. Solution
NMR spectra were recorded at 25 °C on a multinuclear FT-NMR
spectrometer ARX300 (Bruker) at 300.1 (1H), 75.5 (13C), and
121.5 (31P) MHz in CDCl3 unless indicated otherwise. Chemical
shifts (d in ppm) are referred to tetramethylsilane for 1H and 13C
and H3PO4 (85%) for 31P. Coupling constants mean JHH in 1H and
JPC in 13C NMR data unless indicated otherwise. For signals that
could be assigned, the positions of the respective proton and car-
bon nuclei are indicated, for phenyl by o, m, p or i, for cyclohexyl
(b) (2:1:1 Molar ratio): A solution of glyoxylic acid (1.096 g,
11.9 mmol) in diethyl ether (50 mL) was added to a solution
of diphenylphosphine (1.11 g, 5.96 mmol) and diethylamine
(0.63 mL, 6.12 mmol) in diethyl ether (20 mL). After stirring
overnight the precipitate was worked up as described in (a),
yield: 1.69 g (70%). The NMR data are in good accordance
with the above values.
by
a, b, c, d; else only phenyl or cHex is noted. Detection of CH
and Cq is based on CH-COSY or DEPT-135 measurements or NOE-
mediated higher intensities of CH than Cq signals. NMR measure-
ments of oligo- and polyethylenes were performed as described
earlier [19a]. The mass spectrum of thermolyzed 5d was measured
with a single focusing mass spectrometer AMD40 (Maurer) with
direct inlet and heating the sample in a small crucible in the push
rod. Elemental analyses were carried out with a CHNS-932 ana-
lyzer from LECO using standard conditions.
4.2.2. tert-Butylammonium-(rac/meso)-
diphenylphosphoniumbis(glycolate) semihydrate (1b)
Glyoxylic acid hydrate (32 mg, 0.35 mmol) and 3b (122 mg,
0.35 mmol) were dissolved in D2O and slightly warmed for dissolu-
tion. 31P and 1H NMR spectra in D2O displayed quantitative forma-
tion of 1b. Removal of the solvent in vacuum gave the semihydrate.
Anal. Calc. for C20H26NO6PÁ0.5H2O (407.40 + 9.08): C, 57.68; H,
6.48; N, 3.36. Found: C, 57.56; H, 6.34; N, 3.29%. This was recrystal-
lized from a small amount of methanol, mp. 111–113 °C. 1H NMR
(D2O): d = 1.29 (s, 9H, CMe3), 3.28 (s, 3H, 1 MeOH), 5.84 (d,
4.2. Synthesis and characterization of phosphonium- and
phosphinoglycolates
2
2JPH = 7.5 Hz, 1H, PCHA), 6.00 (d, JPH = 7.5 Hz, 1H, PCHB), 7.50–
7.95 (m, 10H, 2 phenyl); NH3 and OH of solvent 4.72. 31P{1H}
+
4.2.1. Diethylammonium-(rac/meso)-diphenylphosphoniumbis
(glycolate) (1a)
NMR (D2O): d = 27.67, 27.63; small signals at d = 27.60, 27.56,
intensity increasing with the time, attributed to CH-CD exchange).
(a) (1:1:1 Molar ratio): A solution of glyoxylic acid (494 mg,
5.37 mmol) in diethyl ether (10 mL), prepared in an ultra-
sound bath, was added to a solution of diphenylphosphine
(1.00 g, 5.37 mmol) and diethylamine (0.56 mL, 5.44 mmol;
small excess to compensate for volatility) in diethyl ether
(20 mL). Precipitation started after few minutes. After stir-
ring overnight the product was collected by filtration,
washed twice with ether and dried in vacuum to give
0.80 g (47%) white powder, mp. 121–122 °C. The diastereo-
isomer mixture was soluble in methanol (with solvolysis),
in water (D2O) and insoluble in CDCl3, CD2Cl2 or THF. Anal.
Calc. for C20H26NO6P (407.40): C, 58.96; H, 6.43; N, 3.44.
4.2.3. Diethylammonium-(rac/meso)-
dicyclohexylphosphoniumbis(glycolate) (1c)
A solution of glyoxylic acid hydrate (345 mg, 3.75 mmol) in
diethyl ether (10 mL) was added to a solution of dicyclohexylphos-
phine (0.743 g, 3.75 mmol) and diethylamine (0.39 mL, 3.75 mmol)
in diethyl ether (20 mL). Precipitation started immediately. After
stirring for 24 h the precipitate was filtered, was washed with
diethyl ether and dried in vacuum, yield 0.75 g (48%). Anal. Calc.
for C20H38NO6P (419.50): C, 57.26; H, 9.13; N, 3.34. Found: C,
57.45; H, 9.23; N, 3.20%. 1H NMR (D2O): d = 1.20 (t, 3J = 7.3 Hz,
6H, CH3), 1.15–2.10 (m, 20H, cHex), 2.50–2.80 (m, 2H, cHex),

66
N. Peulecke et al. / Polyhedron 41 (2012) 61–69
Table 2
solution. The white precipitate formed on cooling (4 °C, 1d)
Crystal data and structure refinement for 7a.
was filtered, washed with diethyl ether and dried in vacuum
to give 1.7 g (94%) white powder. Anal. Calc. for C18H24NO3P
(333.36): C, 64.85; H, 7.26; N, 4.20. Found: C, 64.75; H, 7.40;
N, 4.35%. 1H NMR (CDCl3): d = 1.19 (t, 3J = 7.3 Hz, 6H, CH3),
Compound
7a
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
Unit cell dimensions
a (Å)
C
18H24NO3PS
365.41
296(2)
0.71073
triclinic
2
2.83 (q, 3J = 7.3 Hz, 4H, N+CH2), 4.93 (d, JPH = 7.4 Hz, 1H,
CH), 7.25–7.36 and 7.48–7.65 (m, 10H, 2 phenyl), 9.88
(vbr, 2H, OH, NH+). 13C{1H} NMR (CDCl3): d = 11.25 (CH3),
42.12 (NCH2), 73.63 (d, 1J = 23.0 Hz, PCH), 127.93 (d,
3J = 7.0 Hz, 2 CH-m), 128.28 (d, 3J = 6.4 Hz, 2 CH-m), 128.31
(CH-p), 128.80 (CH-p), 133.36 (d, 2J = 18.4 Hz, 2 CH-o),
134.37 (d, 2J = 19.2 Hz, 2 CH-o), 135.24 (d, 1J = 14.6 Hz, Cq-
i), 137.17 (d, 1J = 11.6 Hz, Cq-i), 176.65 (d, 2J = 8.9 Hz, COOÀ).
31P{1H} NMR (CDCl3): d = 6.2. In D2O and in CD3OD solvolysis
equilibria were observed: 31P{1H} NMR (D2O): d = 6.7; traces
at d = –40.3 (Ph2PH), –41.7 (t, 1JPD = 33.8 Hz, Ph2PD); 31P{1H}
ꢀ
P1
8.9596(2)
9.5050(2)
12.9697(3
76.038(1)
70.521(1)
66.231(1)
945.63(4), 2
1.283
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
Volume (Å3), Z
DCalc (g/cm3)
Absorption coefficient (mmÀ1
Crystal size (mm)
h range (°)
)
0.271
1
NMR (CD3OD): d = 8.1; traces at d = –41.2 (t, JPD = 33.7 Hz,
0.53 Â 0.50 Â 0.37
3.06–36.59
58728
9049 (0.0294)
Multi scan (SADABS
Ph2PD), –14.0 (unidentified).
(b) Detection by solvolysis of 1a in CD3OD. 1H NMR (CD3OD):
d = 1.27 (t, 3J = 7.3 Hz, 6H, CH3), 3.01 (q, 3J = 7.3 Hz, 6H,
Reflections collected
Independent reflections (Rint
Absorption correction
Maximum/minimum transmissions
Refinement method
)
2
N+CH2), 5.04 (d, JPH = 3.9 Hz, ca. 0.8H, CH, partial H-D
)
0.906/0.870
exchange), 7.25–7.40 (m, 4H, phenyl), 7.45–7.65 (m, 6H,
phenyl); 4.77 (s, CH(OH)2); N+H and OH with solvent 4.88.
13C NMR (CD3OD): d = 11.55 (CH3), 43.40 (N+CH2), 74.1 (d,
1J = 24.9 Hz, PCH), 129.2 (d, 3J = 8.6 Hz, 2 CH-m), 129.3 (d,
3J = 6.9 Hz, 2 CH-m), 129.7 (CH-p), 130.1 (CH-p), 134.6 (d,
2J = 19.4 Hz, 2 CH-o), 135.4 (d, 2J = 19.8 Hz, 2 CH-o), 136.2
(Cq-i), 137.6 (Cq-i), 173.92 (s, COO–); 95.61 (s, CH(OH)2),
185.5 (COO–, glyoxylic acid). 31P{1H} NMR (CD3OD): d = 7.4.
Full-matrix least-squares on F2
217
L.S. parameters
Goodness-of-fit on F2
1.033
Final R indices [I > 2
r
(I)]
R1 = 0.0437, wR2 = 0.1217
R1 = 0.0663, wR2 = 0.1390
0.583 and À0.527
R indices (all data)
Largest difference in peak and hole (eÅÀ3
)
2.99 (q, 3J = 7.3 Hz, 4H, NCH2), 5.17 (d, JPH = 9.3 Hz, 1.3H, PCHA),
2
5.19 (d, JPH = 9.9 Hz, 0.7H, PCHB). 13C{1H} NMR (D2O + d8-THF):
2
d = 12.2 (CH3), 26.8 (CH2-d), 27.3–28.1 (m, CH2-
c
, CH2-b), 31.8 (d,
1J = 36.2 Hz, CH- ), 32.7 (d, 1J = 30.8 Hz, CH-
a
a), 43.9, 44.0 (NCH2),
65.9 (d, 1J = 33.5 Hz, PCHB), 66.5 (d, 1J = 33.7 Hz, PCHA), 173.6
(COO–). 31P{1H} NMR (D2O): d = 33.2 (A), 34.0 (B) (intensity A:B
ca. 2:1). 1H NMR (CD3OD/Et2O): d = 1.18 (t, 3J = 7.2 Hz, 6H, CH3),
1.20–2.20 (m, 20H, cHex), 2.60–2.90 (m, 2H, cHex), 3.04 (q,
4.2.6. Detection of tert-butylammonium-diphenylphosphinoglycolate
(2b)
Dilution of a solution of 3b methanol solvate [10a] in D2O with
water led to spectra indicating formation of 2b. 1H NMR (D2O):
2
2
3J = 7.2 Hz, 4H, NCH2), 5.12 (d, JPH = 7.2 Hz, 1.3H, PCHA), 5.19 (d,
d = 1.35 (s, 9H, CMe3), 3.34 (s, 3H, MeOH), 5.09 (d, JPH = 3.3 Hz,
2JPH = 8.1 Hz, 0.7H, PCHB). 31P{1H} NMR (CD3OD): d = 31.0 (B),
1H, CH), 7.38–7.45 (m, 6H, phenyl), 7.45–7.60 (m, 4H, phenyl).
13C{1H} NMR (D2O): d = 24.15, 24.20 (2s, CMe3), 46.45, 46.47 (2d,
J = 2.0 Hz, CMe3), 50.7 (MeOH), 71.1 (d, 1J = 23 Hz, PCH), 126.1 (d,
3J ꢀ8 Hz, 2 CH-m), 126.2 (d, 3J = 6.3 Hz, 2 CH-m), 126.4 and 127.4
(2s, 2 CH-p), 130.2 (d, 2J = 17.1 Hz, 2 CH-o), 132.0 (d, 2J = 19.3 Hz,
2 CH-o), 130.7 (d, 1J = 10.9 Hz, Cq-i), 133.0 (d, 1J = 11.2 Hz, Cq-i),
175.1 (d, 2J = 8.0 Hz, COOÀ). 31P{1H} NMR (D2O): d = 6.7.
32.0 (A) (intensity A:B ca. 2:1).
4.2.4. Detection of diethylammonium-(rac/meso)-di-tert-
butylphosphoniumbis(glycolate) (1d)
Reaction of a solution of glyoxylic acid hydrate (529 mg,
5.75 mmol) in diethyl ether (10 mL) with di-tert-butylphosphine
(840 mg, 5.75 mmol) and diethylamine (0.60 mL, 5.80 mmol) in
diethyl ether (20 mL) and workup as described for 1c furnished
0.5 g white sticky solid. (Attempts at crystallization from dry
methanol, CD3OD/D2O, methanol/THF or precipitation with hexane
failed and gave mixtures.) 1H NMR (CDCl3): d = 1.29 (t, 3J = 7.2 Hz,
4.2.7. Diethylammonium-di-tert-butylphosphinoglycolate (2d)
Diethylamine (0.87 mL, 8.40 mmol) was added to a solution of
glyoxylic acid hydrate (0.70 g, 7.60 mmol) in diethyl ether
(20 mL). A precipitate was formed which slowly turned to an oil.
Therefore, ether was removed in vacuum and replaced by THF.
To the resulting turbid solution di-tert-butylphosphine (1.11 g,
7.59 mmol), dissolved in THF (10 mL), was added. The solution be-
came clear, but after some time a precipitate was formed. After
stirring overnight the main part of THF was evaporated in vacuum,
diethyl ether was added, the solid separated, washed several times
with dry ether and dried in vacuum to give 1.5 g (67%) white pow-
der. Anal. Calc. for C14H32NO3P (293.38) with 5% (HO)2CHCOOH: C,
55.75; H, 10.66; N, 4.53. Found: C, 55.75; H, 10.76; N, 4.70%. 1H
NMR (CDCl3): d = 1.24 (t, 3J = 7.3 Hz, 6H, CH3), 1.63 (d,
3JPH = 11.6 Hz, 18H, tBu2P), 2.96 (br q, 3J = 7.3 Hz, 4H, N+CH2),
3
6H, CH3), 1.63 (d, JPH = 14.7 Hz, 18H, 2 tBu), 3.03 (br s, 4H,
2
2
NCH2), 5.38 (d, JPH = 6.0 Hz, 0.2H, PCHA), 5.60 (d, JPH = 6.3 Hz,
1.8H, PCHB), 9.04 (vbr s, 2H, NH+); 2 OH/H2O for different samples
from 3.8 to 6.1 (vbr s, 4–6H, 2 OH, H2O). 13C{1H} NMR (CDCl3):
d = 11.26 (CH3), 28.66 (CMe3), 37.83 (d, 1J = 26.4 Hz, PCMe3),
42.26 (NCH2), 67.39 (d, 1J = 38.6 Hz, 1.8 PCHB), 170.34 (COO–);
PCHA at noise level. 31P{1H} NMR (CDCl3): d = 30.4 (B), 38.7 (A)
(intensity A:B ca. 1:9).
4.2.5. Diethylammonium-diphenylphosphinoglycolate (2a)
(a) Synthesis: Diethylamine (0.62 mL, 6.00 mmol, 1.1 equiv.)
was added to
a solution of glyoxylic acid (500 mg,
2
5.43 mmol) in diethyl ether. After stirring overnight all vol-
atiles were removed in vacuum. THF and then Ph2PH (1.01 g,
5.43 mmol) were added to the residual oil. The oil dissolved
after short warming and afforded a clear, slightly yellow
4.75 (br s, 1H, OH), 5.59 (d, JPH = 6.4 Hz, 1H, PCH), 7.90 (vbr, 2H,
3
NH2+); dissociated products 1.23 (d, JPH = 11.6 Hz, tBu2PH), 3.14
1
(d, JPH = 206 Hz, PH, tBu2PH), 4.50 (br s, CH, uncertain). 31P{1H}
NMR (CDCl3): d = 30.1 (2d); 20.5 (tBu2PH), 44.2 (minor, unknown).

N. Peulecke et al. / Polyhedron 41 (2012) 61–69
67
4.2.8. Conversion of 2a to N,N-diethyl-
diphenylphosphinomethylamine (4a)
3J = 11.7 Hz, 4 CH-m), 129.89 (superimposed d, 1J = 103 Hz,
Cq-i), 130.79 (d, 1J = 100.9 Hz, Cq-i), 133.04 (d, 2J = 9.3 Hz, 2
CH-o), 133.14 (d, 2J = 8.9 Hz, 2 CH-o), 134.45 (d, 4J = 2.2 Hz,
CH-p), 134.57 (d, 4J = 2.2 Hz, CH-p), 174.33 (COOÀ). 31P{1H}
NMR: d(D2O) = 37.6, d(CDCl3) = 32.0.
Heating of 2a in d8-THF for 1 h (reflux) caused almost quantita-
tive amine condensation and decarboxylation to 4a. 1H NMR (d8-
THF): d = 0.96 (t, 3J = 7.1 Hz, 6H, CH3), 2.69 (qd, 3J = 7.1,
2
4JPH = 0.6 Hz, 4H, N+CH2), 3.27 (d, JPH = 4.2 Hz, 1H, CH), 7.25–7.30
(b) A solution of glyoxylic acid hydrate (764 mg, 8.3 mmol) in
diethyl ether (10 mL) was added at room temperature to an ethe-
real solution (20 mL) of tBuNH2 (0.96 mL, 9.14 mmol) and Ph2PHO
(1.68 g, 8.3 mmol), freshly prepared from chlorodiphenylphos-
phine and aqueous soda solution in ether. A white precipitate
was formed immediately. The mixture was stirred overnight, the
precipitate collected, washed with diethyl ether and dried in vac-
uum to give 2.3 g (79%) colourless crystals. The NMR data are in
good accordance with the values given above.
and 7.40–7.50 (m, 10H, 2 phenyl). 13C{1H} DEPT-135 NMR (d8-
THF): d = 12.02 (CH3), 48.60 (d, 3J = 8.9 Hz, NCH2), 57.89 (d,
1J = 2.7 Hz, PCH2N), 128.87 (d, 3J = 11.1 Hz, 4 CH-m), 128.89 (2
CH-p), 133.72 (d, 2J = 18.1 Hz, 4 CH-o), 140.00 (d, 1J = 13.4 Hz, 2
Cq-i). 31P{1H} NMR (d8-THF): d = –26.4. The phosphorus chemical
shift is in good agreement with the reported value [16].
4.3. Synthesis and characterization of phosphinoylglycolates
4.3.1. Diethylammonium-diphenylphosphinoylglycolate (5a)
4.3.3. Diethylammonium-dicyclohexylphosphinoyl glycolate (5c)
(a) Aqueous hydrogen peroxide (0.10 mL, 30%, 0.88 mmol) was
added at 20 °C to a solution of 1b (150 mg, 0.368 mmol) in
water (10 mL). After stirring overnight to complete the oxi-
dation, the solvent was removed in vacuum. The residual
oil was washed with a small amount of hexane and diethyl
ether to give 130 mg (98%) white solid, mp. 150 °C. Anal.
Calc. for C18H24NO4PÁH2O (349.36 + 18.02): C, 58.85; H,
7.13; N, 3.81. Found: C, 59.07; H, 7.16; N, 3.89%. 1H NMR
(CDCl3): d = 1.10 (br m, 6H, CH3), 2.85 (br m, 4H, NCH2),
(a) Aqueous H2O2 (100 lL, 30%) was added at room temperature
to a solution of 1c (163 mg, 0.50 mmol) in water (10 mL).
Workup as described for 5a gave 120 mg of a hygroscopic
viscous material that slowly solidified, mp. 112–115 °C. Anal.
Calc. for C18H36NO4PÁH2O (379.58): C, 56.97; H, 10.09; N,
3.69. Found: C, 57.31; H, 9.87; N, 3.49%. 1H NMR (CDCl3):
d = 1.15–2.20 (m, 22H, cHex), 1.31 (t, 3J = 7.2 Hz, 6H, CH3),
2
3.49 (q, 3J = 7.2 Hz, 4H, NCH2), 4.44 (d, JPH = 8.5 Hz, 1H,
PCH), 8.80 (vbr, 5H, H2O, OH, NH2+). 13C{1H} NMR (CDCl3):
d = 11.09 (CH3), [24.89 (d, J = 2.4 Hz), 25.03 (d, J = 2.4 Hz),
25.41 (d, J = 2.2 Hz), 25.63 (d, J ꢀ 2 Hz), 25.80 and 25.87
2
4.87 (d, JPH = 7.1 Hz, 1H, PCH), 7.35–7.55 (m, 6H, phenyl),
7.75–7.80 (m, 4H, phenyl), 8.40 (vbr, 5H, H2O, OH, NH2+).
31P{1H} NMR (CDCl3): d = 33.1; trace at d = 21.7 (Ph2PHO).
(b) Diethylamine (0.57 mL, 5.46 mmol) and Ph2PHO (1.10 g,
5.44 mmol) was added to a solution of glyoxylic acid hydrate
(500 mg, 5.43 mmol) in THF (5 mL) in a Teflon autoclave
(10 bar). The mixture was heated in a microwave system
(microCHEMIST from MLS) twice for 5 min at 60 °C. After
cooling, the white precipitate was collected by filtration,
washed with a small amount of THF and dried in vacuum
to give a spectroscopically pure product (yield not deter-
mined). 1H NMR (CDCl3): d = 1.16 (t, 3J = 7.3 Hz, 6H, CH3),
(2s) or 25.84 (d, J = 5.2 Hz), four CH2-
c and CH2-d], 26.39
(d, 2J = 12.6 Hz, 2 CH2-b), 26.60 (d, 2J = 12.6 Hz, CH2-b),
26.68 (d, 2J = 12.6 Hz, CH2-b), 34.12 (d, 1J = 62.0 Hz, CH-
),
a
34.73 (d, 1J = 60.7 Hz, CH-
a), 42.18 (NCH2), 68.26 (d,
1J = 68.3 Hz, PCHO), 174.17 (COOÀ). 31P{1H} NMR (CDCl3):
d = 55.2.
(b) A solution of glyoxylic acid hydrate (558 mg, 6.06 mmol) in
diethyl ether (20 mL) was added at room temperature to
an ethereal solution (10 mL) of Et2NH (0.64 mL, 6.1 mmol)
and cHex2PHO (1.30 g, 6.06 mmol). The initial precipitate
turned after some minutes to viscous oil but after stirring
over night back to a white solid. Filtration, washing with
Et2O and drying in vacuum gave 1.3 g (59%) white powder.
1H NMR indicates OH/NH2+ at d = 9.59 (vbr s, 3H); the other
1H and 13C NMR data are in good accordance with the above
values. 31P{1H} NMR: d(CDCl3) = 52.6, d(D2O) 57.7.
2
2.93 (m, 4H, NCH2), 4.75 (d, JPH = 8.4 Hz, 1H, PCH), 5.9
(vbr s, 1H, OH), 7.38–7.55 (m, 6H, phenyl), 7.78–7.89 (m,
4H, phenyl), 9.4 (vbr, 2H, NH2+). 31P{1H} NMR (CDCl3):
d = 31.4. 13C{1H} NMR (CDCl3): d = 11.20 (CH3), 42.03
(NCH2), 71.48 (d, 1J = 82.1 Hz, PCH), 128.22 (d, 3J = 11.8 Hz,
2
CH-m), 128.35 (d, 3J = 11.6 Hz,
2 CH-m), 131.67 (d,
2J = 9.4 Hz, 2 CH-o), 131.73 (d, 2J = 8.8 Hz, 2 CH-o), 131.82
(superimposed d, 4J = 3 Hz, CH-p), 132.00 (d, 4J = 2.7 Hz,
CH-p), 129.74 (d, 1J = 98.2 Hz, Cq-i), 132.00 (d, 1J = 99.8 Hz,
Cq-i), 171.86 (COOÀ).
4.3.4. Diethylammonium-2-di-tert-butylphosphinoyl glycolate (5d)
(a) Aqueous H2O2 (30%, 150 lL, 1.32 mmol) was added at room
temperature to a solution of 1d (245 mg, 0.89 mmol) in
4.3.2. tert-Butylammonium-diphenylphosphinoylglycolate (5b)
water (10 mL). Workup as described for 5a gave 200 mg
(77%) white solid, mp. 134–136 °C. Anal.
Calc. for
(a) Compound 3bÁMeOH [10a] (379 mg, 1.09 mmol) was dis-
C
14H32NO4PÁH2O (309.38 + 18.02): C, 51.36; H, 10.47; N,
solved in water / THF (2:1) to form an equilibrium mixture
4.28. Found: C, 51.46; H, 10.44; N, 4.53%. 1H NMR (CDCl3):
3
of 1b and 2b. Aqueous H2O2 (30%, 122
lL) was added at
d = 1.30 (t, 3J = 7.3 Hz, 6H, CH3), 1.32 (d, JPH = 13.6 Hz, 9H,
3
0 °C to this solution. After 24 h the solvent was removed in
vacuum. The sticky residue was washed with diethyl ether
and dried in vacuum to give 350 mg (92%) white powder,
mp. 177–179 °C. Anal. Calc. for C18H24NO4P (349.36): C,
61.88; H, 6.92; N, 4.01. Found: C, 61.43; H, 7.02; N, 4.06%.
1H NMR (CDCl3): d = 1.18 (s, 9H, CMe3), 4.79 (d, 2JPH = 4.1 Hz,
1H, PCH), 7.34–7.50 (m, 6H, phenyl), 7.80–7.90 (m, 4H, phe-
nyl), 8.2 (vbr, 3H, OH, NH2+); 1H NMR (D2O): d = 1.22 (s, 9H,
CMe3), 1.38 (d, JPH = 13.4 Hz, 9H, CMe3), 3.05 (q,
3J = 7.3 Hz, 4H, NCH2), 4.47 (d, JPH = 9.4 Hz, 1H, PCH), 8.75
2
(vbr, 5H, H2O, OH, NH2+). 13C{1H} NMR (CDCl3): d = 11.22
(CH3), 26.78 (CMe3), 27.05 (CMe3), 36.26 (d, 1J = 55.5 Hz,
PCMe3), 36.86 (d, 1J = 53.7 Hz, PCMe3), 41.98 (NCH2), 69.89
(d, 1J = 65.3 Hz, PCH), 174.06 (COOÀ). 31P{1H} NMR (CDCl3):
d = 60.8. Thermolysis mass spectrum (70 eV, 130 °C): m/z
(%) = 246 (2.5) [tBu2PCH = NEt2+], 244 (13), 200 (18), 199
(24), 198 (48), 99 (41), 57 (100).
2
CMe3), 4.96 (d, JPH = 6.1 Hz, 1H, PCH), 7.35–7.45 (m, 4H,
phenyl), 7.45–7.53 (m, 2H, H-p), 7.60–7.72 (m, 4H, phenyl).
13C{1H} NMR (D2O, THF): d = 28.34 (CMe3), 53.58 (d,
J = 6.1 Hz, CMe3), 73.34 (d, 1J = 79.2 Hz, PCH), 130.49 (br d,
(b) A solution of glyoxylic acid hydrate (290 mg, 3.15 mmol) in
diethyl ether (10 mL) was added at room temperature to
an ethereal solution (10 mL) of Et2NH (0.33 mL, 3.2 mmol)

68
N. Peulecke et al. / Polyhedron 41 (2012) 61–69
and tBu2PHO (512 mg, 3.16 mmol). After stirring overnight
The crude product was crystallized from methanol (ca. 4 °C) to give
350 mg (60%) white crystals. Crystal data are compiled in Table 2,
selected bond lengths and angles in Fig. 1. Anal. Calc. for
the precipitate was separated, washed with a small amount
of diethyl ether and dried in vacuum to give 538 mg (55%)
white solid. 31P{1H} NMR (CDCl3): d = 61.2. 1H NMR indicates
C
18H24NO3PS (365.43): C, 59.16; H, 6.62; N, 3.83. Found: C,
+
OH/NH2 at d = 3.9 (vbr, 2H), 9.75 (vbr s, 1H); the other 1H
59.62; H, 6.71; N, 3.84%. 1H NMR (CDCl3): d = 1.06 (t, 3J = 7.2 Hz,
and 13C NMR data (CH-COSY spectra see supplementary
data) are in good accordance with the above values.
6H, Me), 2.79 (br, 4H, NCH2), 4.98 (d, JPH = 2.7 Hz, 1H, PCH),
2
7.35–7.55 (m, 6H, phenyl), 7.80–8.03 (m, 4H, phenyl), 9.23 (vbr,
2H, NH2+). 13C{1H} NMR (CDCl3): d = 11.31 (Me), 42.51 (NCH2),
74.45 (d, 1J = 60.1 Hz, PCHO), 128.14 (d, 3J = 12.2 Hz, 2 CH-m),
128.18 (d, 3J = 12.0 Hz, 2 CH-m), 130.20 (d, 1J = 78.8 Hz, Cq-i),
131.20 (d, 4J = 2.9 Hz, CH-p), 131.64 (d, 4J = 2.8 Hz, CH-p), 131.96
(d, 2J = 9.9 Hz, 2 CH-o), 132.26 (d, 2J = 9.4 Hz, 2 CH-o), 132.57
4.3.5. Diphenylphosphinoyl glycolic acid (6ab)
(a) A solution of 5b (49 mg, 0.14 mmol) in water (20 mL) was
treated with H+ charged cation exchange resin (Amberlyst-
15, 14 g) for 30 min at room temperature and separated.
After washing of the resin with a small amount of water
and with THF the solvent was removed in vacuum to give
38 mg (98%) white solid. 1H NMR (CDCl3): d = 5.14 (d,
2JPH = 7.9 Hz, 1H, PCH), 7.35–7.62 (m, 6H, phenyl), 7.77 (dd,
1
(d, JPC = 81.1 Hz, Cq-i), 171.88 (COOÀ). 31P{1H} NMR (CDCl3):
d = 45.8.
4.4.2. tert-Butylammonium-diphenylthiophosphinoylglycolate
semihydrate (7b)
3
3JPH = 11.7, 3J = 7.2 Hz, 2H, H-o), 7.90 (dd, JPH = 11.9,
Sulfur (25 mg, 0.78 mmol) was added to a solution of the pre-
cipitate mixture of 2b/3bÁH2O, freshly prepared from equimolar
amounts of Ph2PH, tBuNH2 and glyoxylic acid hydrate in diethyl
ether (175 mg, 0.52 mmol 2b), heated shortly to reflux and stirred
for 1d. Evaporation of the solvent gave a pale yellow solid which
was washed with diethyl ether to give 140 mg (73%) pale yellow
powder. Crystallization from a small amount of methanol provides
spectroscopically pure 7b, mp. 150 °C, easily soluble in methanol.
Anal. Calc. for C18H24NO3PSÁ½H2O (365.43 + 9.01): C, 57.74; H,
6.74; N, 3.74. Found: C, 57.79; H, 6.77; N, 4.05%. 1H NMR (CD3OD):
d = 1.34 (s, 9H, CMe3), 5.13 (d, 2JPH = 1.2 Hz, 1H, PCH), 7.38–7.54 (m,
6H, phenyl), 7.90–8.03 (m, 4H, phenyl); OH 4.87. 13C{1H} NMR
(CD3OD): d = 27.71 (CMe3), 52.64 (CMe3), 75.11 (d, 1J = 58.7 Hz,
PCH), 129.02 (d, 3J = 12.1 Hz, 2 CH-m), 129.15 (d, 3J = 11.9 Hz, 2
CH-m), 132.20 (d, 4J = 2.8 Hz, CH-p), 132.35 (d, 4J = 2.9 Hz, CH-p),
3J = 7.2 Hz, 2H, H-o). 13C{1H} NMR (CDCl3): d = 70.68 (d,
1J = 75.9 Hz, PCH), 127.38 (d, 1J = 102.4 Hz, Cq-i), 128.58 (d,
3J = 12.8 Hz, 2 CH-m), 128.75 (d, 3J = 12.5 Hz, 2 CH-m),
128.90 (d, 1J = 102.3 Hz, Cq-i), 131.65 (d, 2J = 9.5 Hz, 2 CH-
o), 132.18 (d, 2J = 9.5 Hz, 2 CH-o), 132.78 (br, 2 CH-p),
170.73 (COOH). 31P{1H} NMR (CDCl3): d = 34.0.
(b) A solution of glyoxylic acid hydrate (210 mg, 2.28 mmol) in
diethyl ether (10 mL) was added at room temperature to
an ethereal solution (20 mL) of Ph2PHO (460 mg,
2.28 mmol). An oily precipitate was formed slowly which
on treating in an ultrasound bath (30 min) turned to a solid
precipitate. Filtration and washing with a small amount of
ether gave 520 mg (82%) white powder. Anal. Calc. for
C
14H13O4P (276.22): C, 60.87; H, 4.74. Found: C, 60.64; H,
4.85%. The 1H, 31P and 13C NMR data are in very good accor-
dance with the above data.
133.40 (d, 2J = 9.7 Hz,
133.46 (d, 2J = 9.7 Hz,
2
2
CH-o), 133.42 (d, 1J = 79.3 Hz, Cq-i),
CH-o), 133.75 (d, 1J = 78.6 Hz, Cq-i),
172.95 (COO–). 31P{1H} NMR: d(CD3OD) = 47.4, d(CDCl3) = 46.5.
4.3.6. Dicyclohexylphosphinoyl glycolic acid hydrate (6c)
A solution of 5c (69 mg, 0.182 mmol) in water/THF (18/2 mL)
treated with H+ charged Amberlyst-15 (10 g) gave 47 mg (84%)
white solid. Anal. Calc. for C14H25O4PÁH2O (306.33): C, 54.89; H,
8.88. Found: C, 54.71; H, 9.02%. 1H NMR (CDCl3): d = 1.18–2.25
4.4.3. Diphenylthiophosphinoylglycolic acid (8ab)
A solution of 7a (155 mg, 0.42 mmol) in H2O/THF was treated
with H+ charged Amberlyst 15, filtered and washed with THF. Re-
moval of THF gave 90 mg (73%) of water-insoluble white solid,
mp. 156.5–158 °C. Anal. Calc. for C14H13O3PS (292.29): C, 57.53;
H, 4.48. Found: C, 57.2; H, 4.50%. 1H NMR (CDCl3): d = 4.3 (vbr,
1H, OH), 5.12 (d, 2JPH = 7.1 Hz, 1H, PCH), 7.45–7.66 (m, 6H, phenyl),
7.85–8.03 (m, 4H, phenyl), 8.8 (vbr, 1H, COOH). 13C{1H} NMR
(CDCl3): d = 73.01 (d, 1J = 55.6 Hz, PCH), 126.98 (d, 1J = 81.0 Hz,
Cq-i), 128.24 (d, 1J = 78.1 Hz, Cq-i), 128.84 (d, 3J = 12.5 Hz, 2 CH-
m), 128.92 (d, 3J = 12.7 Hz, 2 CH-m), 132.17 (d, 2J = 10.7 Hz, 2 CH-
o), 132.48 (d, 2J = 10.0 Hz, 2 CH-o), 132.79 (d, 4J = 2.6 Hz, CH-p),
132.99 (d, 4J = 3.6 Hz, CH-p), 170.18 (COOH). 31P{1H} NMR (CDCl3):
d = 45.0.
2
(m, 22H, cHex), 4.67 (d, JPH = 8.9 Hz, 1H, PCH), 5.80 (vbr, 3H, OH,
H2O). 13C{1H} NMR (CDCl3): d = [24.71 (d, J = 2.6 Hz), 25.00 (d,
J = 3.5 Hz), 25.20 (d, J = 2.1 Hz), 25.67 (d, 3J = 5.5 Hz), 26.30 (d,
2J = 11.8 Hz), 26.35 (d, 2J = 13.1 Hz), 2 CH2-d, 4 CH2-
c
, 4 CH2-b],
33.87 (d, 1J = 60.9 Hz, CH- ), 34.77 (d, 1J = 61.1 Hz, CH-
a a), 66.07
(d, 1J = 64.6 Hz, PCH), 172.36 (COOH). 31P{1H} NMR (CDCl3):
d = 58.2.
4.3.7. Di-tert-butylphosphinoyl glycolic acid (6d)
A solution of 6d (50 mg, 0.16 mmol) in water (20 mL) treated
with H+ charged Amberlyst-15 (12 g) gave 38 mg (98%) white solid,
1
mp. 160–162 °C. Anal. Calc. for C10H21O4PÁ 4H2O (236.25 + 4.50): C,
4.5. Oligomerization of ethylene
49.89; H, 9.00. Found: C, 49.69; H, 9.14%. 1H NMR (CDCl3): d = 1.37
3
3
(d, JPH = 13.6 Hz, 9H, PCMe3), 1.41 (d, JPH = 13.5 Hz, 9H, PCMe3),
Screening of 1a–d for formation of nickel ethylene oligomeriza-
tion catalysts with Ni(COD)2 in the presence of ethylene (30–
50 bar) was performed as batch procedure in a stainless steel auto-
clave (75 mL) as reported earlier in more details [19a]). Solutions of
4.66 (d, JPH = 9.0 Hz, 1H, PCH); (OH d > 10). 13C{1H} NMR (CDCl3):
2
d = 25.93 (CMe3), 26.21 (CMe3), 35.97 (d, 1J = 54.4 Hz, PCMe3), 37.16
(d, 1J = 53.0 Hz, PCMe3), 65.29 (d, 1J = 63.7 Hz, PCH), 173.56
(COOH). 31P{1H} NMR (CDCl3): d = 68.3.
Ni(COD)2 (ca. 100
lmol) in THF (10 mL) were added at ca. 0 °C (for
1a 20 °C) to 1a-d (ca. 100
lmol) in THF (10 mL). The mixture was
4.4. Synthesis and characterization of thiophosphinoylglycolates
stirred for 30 min at 20 °C and added by syringe into the N2-filled
autoclave. Then the autoclave was pressurized with ethylene (30–
50 bar) and heated for 15 h with electronic pressure monitoring.
After cooling to 0–10 °C unconverted ethylene was released and
the weight difference determined to calculate ethylene conversion.
The product mixture was transferred to a flask and separated by
flash distillation (80 °C/1 Torr). The distillate was analyzed by GC.
4.4.1. Diethylammonium-diphenylthiophosphinoylglycolate (7a)
A mixture of 1a (650 mg, 1.60 mmol) with sulfur (99 mg,
3.09 mmol) in THF (15 mL) and a small amount of MeOH was
heated shortly to reflux and stirred for 1d. Evaporation of the sol-
vent gave a pale yellow solid which was washed with diethyl ether.

N. Peulecke et al. / Polyhedron 41 (2012) 61–69
69
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The residual polymer was stirred for 1d with methanol/hydrochlo-
ric acid (1:1, v/v), then thoroughly washed with methanol and fi-
nally air dried. The polymer was characterized by 1H NMR after
swelling in 0.5 mL of C6D5Br at 120 °C for 24 h (under nitrogen).
The density of the polymer was determined with a small tablet,
prepared at 10 kbar, by the floating method in ethanol/water. Re-
sults are compiled in Table 1.
4.6. Crystal structure analysis of 7a
A suitable single crystal of 7a was mounted on a glas⁄s fiber
with inert oil. Data were recorded at room temperature on a Bru-
ker-Nonius Apex X8-CCD diffractometer using Mo Ka-radiation
(k = 0.71073 Å). Crystal data are summarized in Table 2. The struc-
ture was solved by direct methods and refined by full-matrix least-
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were fixed on idealized positions and refined using riding models.
Selected bond lengths and angles are given in Fig. 1.
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Acknowledgements
We thank B. Witt and I. Siegert for numerous solution NMR
spectra.
(b) C. Meyer, M. Scherer, H. Schönberg, H. Rügger, S. Loss, V. Gramlich, H.
Grützmacher, Dalton Trans. (2006) 137.
Appendix A. Supplementary data
[13] (a) M. Tepper, O. Stelzer, T. Häusler, W.S. Sheldrick, Tetrahedron Lett. 38
(1997) 2257;
CCDC 863611 contains the supplementary crystallographic data
for 7a. These data can be obtained free of charge via http://
www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ,
UK; fax: +44 1223 336 033; or e-mail: deposit@ccdc.cam.ac.uk.
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.poly.2012.04.019.
(b) D.J. Brauer, S. Schenk, S. Roßenbach, M. Tepper, O. Stelzer, T. Häusler, W.S.
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