Syntheses, characterization of and studies on the electrochemical behaviour of ferrocenyl dithiophosphonates and 4-methoxyphenyl dithiophosphonates

Article abstract of DOI:10.1080/10426507.2016.1238368

Some 1,3-dithiadiphosphetane 2,4-disulfides (X₂P₂S₄, X: Fc, FcLR; X: CH₃O?C₆H₄?, LR) were allowed to react with alcohols to obtain dithiophosphonic acids (X(OR)PS₂H). These were converted to the corresponding ammonium salts. The salts were of the structures [Fc(OR)PS₂]^?[NH₄]⁺, R: 3-methyl-1-butyl- for I; 1-phenyl-1-propyl- for II; 3-pentyl- for III; 3-phenyl-1-propyl- for IV and [CH₃O?C₆H₄(OR)PS₂]^?[NH₄]⁺, R: 3-methyl-1-butyl- for V and 1-phenyl-1-propyl- for VI. To the best of our knowledge, all the compounds except V were prepared for the first time. The compounds synthesized were characterized by elemental analysis, NMR (¹H,¹³C,³¹P), MS, FTIR, and Raman spectroscopies. Electrochemical behaviors of I–VI at disposable pencil graphite electrode (PGE) were investigated by using cyclic voltammetry (CV) and square-wave voltammetry (SWV). Adsorption and diffusion patterns of all the compounds on the PGE were also studied. Two electroactive groups were identified in the compounds I–IV and only one in V and VI. The ferrocenyl groups of I-IV were oxidized at around 0.4?V. The same compounds display a second, more intense CV band at 0.8?V. The corresponding band for the compounds V–VI appears at around 0.6?V with a much weaker intensity. It is suggested that the ferrocenyl group introduced into the structures stabilizes the radical species formed as the product of the oxidation of the dithiophosphonato group.

Full text of DOI:10.1080/10426507.2016.1238368

Phosphorus, Sulfur, and Silicon and the Related Elements
ISSN: 1042-6507 (Print) 1563-5325 (Online) Journal homepage: http://www.tandfonline.com/loi/gpss20
Syntheses, characterization of and studies on
the electrochemical behaviour of ferrocenyl
dithiophosphonates and 4-methoxyphenyl
dithiophosphonates
Ertuğrul Gazi Sağlam, Sevcan Erden, Özgür Tutsak, Dilek Eskiköy Bayraktepe,
Zehra Yazan Durmuş, Hakan Dal & Ahmet Ebinç
To cite this article: Ertuğrul Gazi Sağlam, Sevcan Erden, Özgür Tutsak, Dilek Eskiköy
Bayraktepe, Zehra Yazan Durmuş, Hakan Dal & Ahmet Ebinç (2016): Syntheses,
characterization of and studies on the electrochemical behaviour of ferrocenyl
dithiophosphonates and 4-methoxyphenyl dithiophosphonates, Phosphorus, Sulfur, and
Silicon and the Related Elements, DOI: 10.1080/10426507.2016.1238368
To link to this article: http://dx.doi.org/10.1080/10426507.2016.1238368
Accepted author version posted online: 21
Sep 2016.
Published online: 21 Sep 2016.
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Date: 04 January 2017, At: 06:51

PHOSPHORUS, SULFUR, AND SILICON
http://dx.doi.org/./..
Syntheses, characterization of and studies on the electrochemical behaviour of
ferrocenyl dithiophosphonates and -methoxyphenyl dithiophosphonates
a
b
a
b
b
c
Ertu g˘ rul Gazi Sa g˘ lam , Sevcan Erden , Özgür Tutsak , Dilek Eskiköy Bayraktepe , Zehra Yazan Durmu s¸ , Hakan Dal ,
and Ahmet Ebinça
a
b
c
Department of Chemistry, Bozok University, Yozgat, Turkey; Department of Chemistry, Ankara University, Tando g˘ an, Ankara, Turkey; Department of
Chemistry, Anadolu University, Yeniba g˘ lar, Eski s¸ ehir, Turkey
ABSTRACT
ARTICLE HISTORY
Received  April 
Accepted  September 
Some 1,3-dithiadiphosphetane 2,4-disulfides (X P S , X: Fc, FcLR; X: CH O–C H –, LR) were allowed to react
2
2
4
3
6
4
with alcohols to obtain dithiophosphonic acids (X(OR)PS H). These were converted to the corresponding
2
−
+
ammonium salts. The salts were of the structures [Fc(OR)PS ] [NH ] , R: 3-methyl-1-butyl- for I; 1-phenyl-1-
2
4
KEYWORDS
−
+
propyl- for II; 3-pentyl- for III; 3-phenyl-1-propyl- for IV and [CH O–C H (OR)PS ] [NH ] , R: 3-methyl-1-butyl-
3
6
4
2
4
Ferrocenyl Lawesson
reagent; Lawesson reagent;
ferrocenyl-
dithiophosphonate;
thio-phosphorus
compounds; cyclic
voltammetry
for V and 1-phenyl-1-propyl- for VI. To the best of our knowledge, all the compounds except V were prepared
for the first time.
The compounds synthesized were characterized by elemental analysis, NMR ( H, 13C, 31P), MS, FTIR, and
Raman spectroscopies. Electrochemical behaviors of I–VI at disposable pencil graphite electrode (PGE) were
investigated by using cyclic voltammetry (CV) and square-wave voltammetry (SWV). Adsorption and diffu-
sion patterns of all the compounds on the PGE were also studied.
1
Two electroactive groups were identified in the compounds I–IV and only one in V and VI. The ferrocenyl
groups of I-IV were oxidized at around 0.4 V. The same compounds display a second, more intense CV band
at0.8V. ThecorrespondingbandforthecompoundsV–VI appearsataround0.6Vwithamuchweakerinten-
sity. It is suggested that the ferrocenyl group introduced into the structures stabilizes the radical species
formed as the product of the oxidation of the dithiophosphonato group.
GRAPHICAL ABSTRACT
Introduction
organo-dithiophosphates and organo-dithiophosphinates.
Excellent reviews setting background information for future
studies have appeared.1
The reaction of perthiophosphonic acid anhydride with alco-
hols and Grignard reagents is known to produce dithiophos-
phonic acids (DTPOA) and dithiophosphinic acids (DTPA),
respectively.1 Due to their agricultural and industrial applica-
tions these compounds and their metal complexes are of inter-
est. Among the applications are their use as additives to lubri-
0,11
As to the ferrocenyl dithiophosphonates, a ferrocenyl
perthiophoshonic acid anhydride, FcLR, the first example of the
starting materials, was first explored by Woollins and cowork-
–3
12
ers. Similar to other perthiophoshonic acid anhydrides, such
as Lawesson reagent, LR, FcLR reacts with alcohols to give
ferrocenyl-dithiophosphonic acid (Fc-DTPOA). In recent years,
several investigations on ferrocenyl dithiophosphonate deriva-
tives have been carried out. Among these, work involving the
4
5
6,7
cant oils; antioxidant agents; extraction reagents for metals;
insecticides and pesticides.8
,9
Literature reports related to organo-dithiophosphonates
and their metal derivatives are relatively rare compared to
CONTACT Ertu g˘ rul Gazi Sa g˘ lam
saglameg@gmail.com
Department of Chemistry, Faculty of Science and Art, Bozok University,  Yozgat, Turkey.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/gpss.
Supplemental data for this article can be accessed on the publisher’s website at http://dx.doi.org/./..
©
 Taylor & Francis Group, LLC

˘
E. G. SAGLAM ET AL.
2
as expected. The signal of these protons are accidentally over-
lapped with those of the five-proton signals related to the
unsubstituted ferrocene ring (unsbs-Fcring). The integral area
of the combined signal group corresponds to seven-protons as
1
expected. In the H NMR spectra of the compounds I, III and
ꢀ
IV the protons subs-Fcring-C2H and -C2 H appear at around
Scheme . Synthesis of perthiophosphonic acid anhydride through the reaction of 4.6 ppm as multiplets. We suggest that the two protons are
HS and monothiophosphine dichlorides.
chemically nonequivalent; splitting by coupling to phosphorus
into two and further splitting by coupling to the neighbouring
oxidative S-S coupling of the compounds is worth to bi men-
protons so as to appear as a multiplet. The spin-spin coupling
tioned.1
3–16
Electrochemical studies on ferrocenyl dithiophos-
constants are not discernable. Compound II displays the same
phonates and other ferrocene bearing compounds have also
protons at 4.42 and 4.49 ppm as singlets, indicating that the two
appeared.1
5–20
protons are nonequivalent. The two signals are too far apart
3
(
28 Hz) to be regarded as a JPH coupling. We are inclined to
comment that the couplings to phosphorus and also to the
neighbouring protons are too small to be observable. Precise
assigments of these two peaks were not done.
Results and discussion
Perthiophosphonic acid anhydrides, namely, 1,3,2,4-
dithiadiphosphetane 2,4-disulfides, are important starting
1
The H NMR signals of the C9H protons in II, III, and IV are
materials for the synthesis of organodithiophosphorus com-
obviously split by three-bond coupling to phosphorus, which is
pounds.2
1,22
Two different routes are followed for the synthesis
the case for similar structures.2
7–29
The signal of the proton C9H
of the perthiophosphonic acid anhydrides. One route is based
on the reaction of monothiophosphine dichlorides with hydro-
gen sulphide (Scheme 1). This approach is generally avoided
because, the reaction of monothiophosphindichloride and
hydrogen sulphide requires temperatures above 210°C and is
violently exothermic.23
The second route is a milder one and based on the direct reac-
tion of an electron donating aromatic compound with P4S10.24
This reaction is relatively safer and therefore the method of
choice (Scheme 2).
In this work, ammonium salts of four new ferrocenyl dithio-
phosphonic acids and a new dithiophosphonic acid were synthe-
sized through the reaction of two perthiophosphonic acid anhy-
drides and alcohols. The procedure is summarized in Scheme 3.
in compound I is splitted into two lines by coupling to phos-
3
phorus ( JPH = 13.5 Hz) and further splitted by coupling to the
3
geminal two protons ( JHH = 6.8 Hz). Obviously the accidental
magnitudes of the couplings gave rise to a pseudo quartet. The
CH2 protons coded as C10H in compound II are diastereotopic
as reflected by the doublet of multiplets located between 1.7
and 2.0 ppm. The phenyl protons of compounds II, IV, and VI
appear at around 7.1 ppm as expected.
The aromatic protons of compound VI and the phosphorus
nucleus constitute an AA’MM’X spin system. The proton signals
appear essentially in an AMX pattern, because JAM’ and JA’M are
too small to be observable. The chemical shift assignment of the
aromatic protons in this compound was made by referring to the
magnitudes of the coupling constants to phosphorus. The ortho-
protons appear to be splitted by 13.6 Hz by coupling to phospho-
rus (three-bond coupling) and further splitted by 8.7 Hz due to
coupling to the geminal protons. The meta-protons interact with
the phosphorus to the extent of a 2.7 Hz four-bond coupling.
Spectroscopic studies
IR and Raman spectra
3
,30
The prominent IR and Raman bands of the compounds are listed These findings agree well with the literature.
13
in Table 1. In the IR spectra the asymmetric and symmetric (PS)
In the C NMR spectra of all compounds, the two-bond cou-
2
stretching signals (νsym and νasym) of the compounds appear in pling constants J for the P-O-C carbon atoms are observed to
PC
−
1
−1
the regions of 580–523 cm and 650–625 cm , respectively. be in the narrow range of 8.8–7.4 Hz. The one bond couplings
1
In the Raman spectra, similar signals appear in the regions of
JPC for C1 in compounds I, II, III, and IV are in the expected
range (125.3, 123.5, 124.7, and 124.9 Hz, respectively).
The corresponding coupling in compound VI is remarkably
−1
−1
5
85–525 cm and 657–625 cm , respectively.
In the IR spectra the characteristic νN–H band is observed at
−
1
−1
between 3159 and 3080 cm for IR and 3098–3113 cm for different (109.5 Hz), reflecting the difference between five- and
Raman. The frequencies of the corresponding signals in the IR six-membered aromatic rings. These values are in agreement
and the Raman spectra of the same compound are quite com- with those reported for similar structures.2
9–31
parable as expected. All these values are in agreement with the
In compounds I and VI the signals of the carbon atoms C2
literature.3
,13,25,26
ꢀ
and C2 coincide, indicating a chemical equivalence. The same
ꢀ
applies to the signals of C3 and C3 . However, in compounds II
ꢀ
and III the chemical shifts of C2 and C2 differ by 0.5–0.6 ppm
NMR spectra
(
70.9 and 71.4 ppm for compound II and 70.6 and 71.2 ppm for
The H, 13C, and 31P NMR data of the compounds are given in compound III). The signals of the carbon atoms C3 and C3 are
1
ꢀ
the experimental section. The numbering scheme for the pro- also different. This is probably due to the restricted rotation of
tons is given in Figure 1.
the branched alkyl, aryl, and 3-pentyl groups. This comment is
1
In the H NMR spectra of the compounds I, II, III, and supported by the fact that the signals originating from C2 and
ꢀ
IV signals of the protons coded as subs-Fcring-C3H and subs- C2 of compounds I, IV, and VI are chemically equivalent. Pre-
ꢀ
Fcring-C3 H are chemically equivalent in all the compounds sumably, the alkyl groups with a straight chain at the proximity

PHOSPHORUS, SULFUR, AND SILICON
3
Scheme . Synthesis of perthiophosphonic acid anhydride.
Scheme . Synthesis reaction of the compounds.
The 31P NMR spectra of I, II, III, IV, and VI show singlets
of the phosphorus rotate freely. Two- and three-bond P-C cou-
pling constants for compounds I, II, III, and IV are compara- at 107.6, 103.3, 105.9, 108.2, and 105.1 ppm, respectively.
ble to those reported for similar structures.2
7–31
The NMR sig-
nal related to the carbon atoms unsubs-Fcring in compounds I,
II, III, and IV appears at ∼69 ppm, showing almost the same
Mass spectra
32
chemical shift as that of pure ferrocene.
The mass spectra of compounds I, II, III, IV, and VI display
molecular ion peaks. The molecular ion peaks of compounds
I, III, IV, and VI are also the principle peaks whereas in com-
pounds II this is not the case. The natural abundance of isotopes
is observable in the structure of the molecular ion signals. Sig-
nal patterns reported for similar compounds agree well with our
31
13
In compound VI the two-bond P– C coupling for the aro-
matic carbon atoms is observed to be 13.6 Hz in the anisole
group. For the same ring the three-bond 31P– C coupling for
the aromatic carbon atoms meta- to phosphorus is 14.9 Hz. The
13
2
3
JPC coupling for C6 is 7.8 Hz and JPC for C7 is 8.2 Hz. These
values compare well with those given in the literature.3
3,34
35
signals.
Table . Selected FTIR and Raman (R) data (cm ) and assignment of the significant bands.
−
ν(PS)(sym) ν(PS)(asym)
ν
ν
(N-H)
(P-O-C)
Compound
IR
R
IR
R
IR
R
IR
R
I
II
III
IV
VI




;




;




;

;

;
;

















;
—


˘
E. G. SAGLAM ET AL.
4
Figure . Numbering scheme for compound I, II, III, IV, and VI.
Electrochemical behavior of the compounds
compared to the parent molecule, ferrocene (Figures 2A and B;
Table 2). This means that the ferrocenyl group makes the oxida-
tion of the P–S group more difficult. The ꢀEp values are fairly
small (0.1 V) which indicates that the redox reaction is quasi-
reversible (Table 2).
As examples, the number of electrons and protons involved
in the electrochemical oxidation of the P–S group was tested by
CV and SWV studies. The influence of the scan rate on the peak
potential (Ep) and also on the peak current (ip) were investigated
The electrochemical behaviors as well as diffusion and adsorp-
tion properties of alkyl ferrocenyl- (I and III); alkyl- 4-
methoxyphenyl- (V); aryl- ferrocenyl (II and IV) and aryl-
4
-methoxyphenyl (VI) dithiophosphonates were studied by
−3
−1
using CV and SWV. 1.00 × 10 mol · L solutions of the title
compounds in a mixture of ethanol and BR buffer (1/1) were
−1
used for CV runs on disposable PGE at a scan rate of 0.100 Vs
.
The CVs are displayed in Figures 2A and B. Solutions of I-IV
adjusted to pH 2.0 gave rise to two well-defined oxidation peaks
at the potentials of approximately 0.30 V and 0.80 V (Figures
2A and B). The CV peak at 0.30 V almost certainly corresponds
to the oxidation of the ferrocenyl group as the voltammogram
of the pure ferrocene indicates. Literature data obtained for
ferrocenyl groups attached to conjugated backbones are com-
parable, despite some changes due to conjugations in those
structures.3
6–38
To judge which electroactive group in the molecules is oxi-
ꢀ
ꢀ
dized in the first oxidation step (Figures 2.A1-1 and 2.B1-1
inset), the CV of I-IV of ferrocene and of compounds V and VI
Figures 2A and B) were examined as pointed above. The higher-
(
potential peaks presumably correspond to an oxidation on the
P-S groups. Literature reports on the electrochemistry of some
dithiophosphonato compounds indicate that an intermoleculer
oxidative -P-S-S-P- coupling is the most likely alternative.1
As is evident in Figure 2(inset) the CV peak corresponding
to the ferrocenyl group reflects a reversible process. This process
is a well known one-electron oxidation.3 A comparison of the
CV relating to compounds V–VI with those of I–IV suggests
that the presence of the ferrocenyl group in the molecules not
only gives rise to an additional oxidation peak but also causes
at least a ten-fold increase in the intensity of the peak related to
the P-S group (Figures 2A and B). Presumably, the ferrocenyl
group introduced into the structures has a promoting effect on
the formation of the radical species thought to have intervened
in the oxidative coupling of the P–S groups. There is also some
5,16
9
0
.2–0.3 V potential shift in the position of the peak towards more
positive values (Table 2).
−

Figure . A) Cyclic voltammograms of I, II, V, and ferrocene (each .×
The position of the ferrocenyl oxidation peaks in compounds
−
−
−
mol.L ) B) II, IV, VI, and ferrocene (each .× mol.L ) at pH ., scan rate
−

I–IV is located at approximately 0.1 V higher potentials as . Vs (inset ferrocenyl moiety).

PHOSPHORUS, SULFUR, AND SILICON
5
−

Table . The electrochemical data relating to the compounds I-VI (. ×  mol is equal to 0.0296V/(nα), n being the number of electrons in the
−

·
L
each at pH .) obtained in methanol + BR buffer (/) on PGE versus Ag/AgCl
40
rate determining step and α the charge transfer coefficient. By
−

(
M KCl). The scan rate is v =  mVs
.
applying this relation, (nα) values for II and III were calculated
to be 0.62 and 0.42, respectively.
ꢀ
ꢀ
Ipa
(μA)
Ipa
(μA)
Ipc
(μA)
Epa
(V)
Epa
(V)
Epc
(V)
Compounds
ꢀEp
SWV studies were also carried out on compounds II and III.
−1
I
II
III
IV
V
VI
.
.
.
.
—
—
.
.
.
.
.
.
.
—
.
.
.
.
—
—
.
.
.
.
.
—
—
.
.
.
.
.
.
.
—
.
.
.
.
—
.
.
.
.
—
—
.
The influence of the frequency (f, s ) of the excitement sig-
nal on the peak potentials was investigated. The peak potentials
shifted to more anodic values with increasing excitement fre-
quency and the corresponding linear equations are as follows:
2
—
.
Ep(V) = 0.047 × logf + 0.56 (with R = 0.9917) for II; Ep(V)
Ferrocene
2
=
0.079 × logf + 0.58 (with R = 0.9717) for III. Applying
the equation “slope = 0.059/nα” given in the literature for this
−3
−1
40,41
using 1.0×10 mol · L solutions of compounds II and III in case,
the values of (nα) were calculated to be 1.25 and 0.75
−1
a
the 0.01–0.50 Vs range. The slopes of the plots logip versus for II and III, respectively. Here n stands for the number of elec-
logv, (about 0.5) also verify that the electrochemical characteris- trons in the overall reaction and therefore not in the rate deter-
tics of the compounds are not influenced by the adsorption phe- mining step. These analyses indicate that the number of elec-
nomena (Figures 3A and B inset logip–logv).40,41
trons involved are 2 for the both compounds.
The peak potentials shift to more anodic values with increas-
A similar analysis on the other compounds shows exactly the
ing scan rate (Figures 3A and B for II and III) and as it was indi- same behavior.
cated before there is no cathodic peak at reverse scan at low scan
The number of protons involved in the overall electrochem-
rate. These findings support us to propose an irreversible oxida- ical process was studied using the CV runs in solutions of dif-
tion mechanism for the compounds.
p
ferent pH values. For each compound, the E values at media
−1
When the scan rate varied from 0.010 to 0.50 Vs a linear of different pH were measured in the pH range 2.0–11.0. The
dependence of the peak potentials Ep (V) upon the logarithm of change of E against the pH can be expressed by the linear equa-
p
−1
2
scan rate (log Vs ) was found. The dependence is represented tions, E (V) = 0.024 × pH + 0.93 (with R = 0.989751) for II;
p
2
2
by the equations, Ep (V) = 0.048 × logυ + 0.8632 (with R = E (V) = 0.017 × pH + 0.84 (with R = 0.9907) for III. The
p
0
(
.9586) for II (Figure 3A) and Ep (V) = 0.071 × logυ + 0.8901 ratio of the number of protons ( ∂) to that of electrons (n) the
2
42
with R = 0.9367) for III (Figure 3B). The theory of voltamme- following equation was used.
−1
try predicts that the slope of the straight line Ep versus log Vs
RT
nF
[Ox]
[Red]
∂RT
nF
ꢀ
+ꢁ
0
Ep = E +
ln
−
ln H
0
In this equation Ep is peak potential in V (vs. Ag/AgCl); E is
the standard peak potential; R is the ideal gas constant taken as
8
.31 J/(mol · K); T is the absolute temperature (here, 298 ± 3 K);
F is the Faraday constant; and [Ox] and [Red] are the molar con-
centrations of the oxidized and the reduced species. Use of this
relation leads to the conclusion that one proton and two elec-
trons take part in the overall electrode mechanism. A similar
analysis for the other four compounds yielded similar results.
Conclusions
Ammonium salts of four ferrocenyldithiophosphonates and two
4
-methoxyphenyl dithiophosphonates were prepared. All of the
compounds except one were synthesized and characterized for
the first time. The characterizations were done by elemental
1
13
31
analysis as well as MS, FTIR, RAMAN, H, C, and P NMR
1
spectroscopies. The H NMR signal of the CH2 protons on
the (α-ethyl)benzyl group of compound II is found to display
diastereotopic nonequivalence. The structurally similar pairs of
1
13
H and C nuclei on the cyclopentadienyl ring attached to phos-
phorus display chemical nonequivalence as well.
Electrochemical studies on PGE reveal that compounds I-IV
display two well defined CV peaks in the methanol-BR buffer
mixture (1/1). The lower-potential peak belongs to the oxida-
tion of the ferrocene group. The position of this peak is at some
Figure . Influence of potential scan rate to peak currents and peak potentials (A) 0.1 V higher potentials compared to that of the parent molecule,
II, (B) III (inset: Potential versus the logarithm of scan rate and logi vs. logv).
p
ferrocene. The second peak is related to the oxidation of the P–S

˘
E. G. SAGLAM ET AL.
6
group. The former is a one electron process causing ferrocenyl pH measurements were made with Thermo Orion Model 720A
moiety to get oxidized to the corresponding cationic species. pH meter attached to an Orion combined-glass pH electrode
The electrochemical reaction causing the latter peak involves (912600).
two electrons and one proton.
The introduction of the ferrocenyl group to the dithiophos-
phonate center appears to have caused a shift towards more
Reagents and solutions
−
2
positive potentials on the position of the oxidation peak of the Stock solutions of the title compounds (all being of 1.00 × 10
−1
P–S group. Interestingly, the intensity of this peak displays more mol · L concentration) were prepared in the Britton-Robinson
−3
−1
than ten-fold increase as compared to other dithiophosphonates buffer (BR). Working solutions (1.00 × 10 mol · L ) were
without ferrocenyl group.
obtained by diluting the stock solution with the same buffer and
the pH value of these solutions were adjusted to the desired val-
−1
ues by dropwise addition of 0.2 mol · L NaOH.
Experimental
Materials and instruments
Voltammetric procedure
Analytical grade ferrocene, P4S10, xylene, 3-methyl-1-butanol,
For CV, 10.0 mL working solutions of the compounds in BR were
placed in the electrochemical cell for each trial. The solution was
deoxygenated by purging with purified argon (99.9%) for 2 min
before the first running and for 30 s between successive run-
nings. The voltammograms were run in the positive direction
by applying a scan from −0.4 to 1.40 V at PGE. All the experi-
ments were carried out at room temperature. A newly polished
and ethanol-rinsed PGE was used in each run. Each voltammet-
ric signal was obtained as the mean of three successive runs.
1-phenyl-1-propanol, 3-pentanol, 3-phenyl-1-propanol, and LR
were purchased from Merck and used directly without further
purification. Benzene, n-hexane and diethyl ether were pur-
chased from Merck and were distilled under nitrogen over a Na
alloy with benzophenone ketyl indicator. FcLR and V were pre-
pared as described in the literature.1
1,43
The LC/MS spectra were recorded with a Waters Micromass
ZQ connected with Waters Alliance HPLC using ESI(+) method
with the C-18 column. Melting points were measured with an
Electrothermal 9200 melting point apparatus using a capillary
1
13
1
31
1
Syntheses of the compounds
tube. H, C{ H}, and P{ H} NMR spectra were recorded
with a Varian Mercury (Agilent) 400 MHz FT spectrometer in
General procedure for the synthesis of compounds I, II, III, and
IV. A total 15–20 mL of benzene was boiled in a round-bottom
flask under reflux and to the boiling liquid, 0.89 mmol (0.50 g) of
FcLR was added. To this mixture, 1.78 mmol of alcohol (0.16 g of
3-methyl-1-butanol, 0.24 g of 1-phenyl-1-propanol, 0.16 g of 3-
pentanol or 0.24 g of 3-phenyl-1-propanol) was added dropwise.
The reaction was carried on until all the solids were dissolved
during which the colour changed from brick-red to brown. The
mixture was left overnight at room temperature and then the
solid impurities were filtered. The Fc-DTPOA in solution was
treated with ammonia gas and the Fc-DTPOA-ammonium salt
was obtained as a yellow-orange powder. This salt was filtered,
washed with hot benzene, n-hexan and finally diethylether and
dried in vacuum desiccator.
1
13
31
CD3OD. SiMe4 ( H, C) and 85% H3PO4 ( P) were used as
standards. Chemical shifts (δ) are given in ppm. IR spectra were
recorded with a Perkin Elmer Spectrum Two Model FT-IR Spec-
trophotometer using the ATR method (200–4000 cm ) and are
reported in cm units. All Raman spectra were measured in the
range of 4000–100 cm , at room temperature, using a Renishaw
in-Via Raman microscope, equipped with a Peltier-cooled CCD
detectors (−70°C). For Raman microscopy, a 50X objective was
usually used and all the spectra were excited by the 785 line
of a diode laser. Microanalyses were performed using a LECO
CHNS-932 CHNS-O elemental analyzer.
−1
−
1
−1
In the electrochemical part of the study all chemicals used
in the preparation of BR solution, namely phosphoric acid
(
Riedel), boric acid (Riedel), acetic acid (Merck) and sodium
hydroxide (Merck) were of analytical reagent grade. Double-
distilled deionized water was used in preparations of all the solu-
tions. The Supplemental Materials contains sample 1H, 13C, 31P
NMR, and mass spectra for products I–VI (Figures S1–S20).
Syntheses of VI. LR (0.50 g, 1.24 mmol) was mixed with 10–
1
5 mL of benzene in a round-bottomed flask (100 mL) and to
this mixture a stoichiometric amount of alcohol (3-phenyl-1-
propanol), 0.34 g, 2.47 mmol was added dropwise. The mixture
was heated to and kept at 60–70°C until complete dissolution
of all solids, which takes 30 minutes roughly. The crude dithio-
phosphonic acid, DTPOA, was filtered, the filtrate was cooled to
Electrochemical apparatus
Voltammetric measurements were made on a CH-instrument
5–10°C, and the acid was converted to compound VI by bub-
(
CHI 660C) Electrochemical Analyzer with cell stand of C3.
bling dry NH3. The precipitated ammonium salt was filtered off
as a colorless powder. This salt was washed with cold benzene
and dried in air.
The pen-nibs (Tombow, Germany; 0.7 mm diameter), were used
as disposable PGEs. A mechanical pencil (Rotring, Germany, T
0
.7) was used as the holder for PGE. Electrical contact with the
PGE was ensured by a copper wire attached to the metallic tip
of the pencil. The PGE assembly was used as the working elec- Ammonium O-3-methyl-1-butyl(ferrocenyl)
trode. A platinum wire (BAS MW-1034) and Ag/AgCl electrode dithiophosphonate], I. 0.49 g, 72%. m.p. 149–151°C. Anal.
−
1
−1
(
stored in 3.0 mol · L KCl solution; MF-2052 RE-5B) were Calcd. for, C15H24FeNOPS2 (385.31 g · mol ): C, 46.76; H, 6.28;
used as the auxiliary and standard electrodes, respectively. All N, 3.64; S, 16.64. Found: C, 46.69; H, 6.19; N, 3.60; S, 16.59%.

PHOSPHORUS, SULFUR, AND SILICON
7
1
3
H NMR (CD3OD): δ = 0.87 (d, JHH = 6.7 Hz, 6H, C12H), C2 coincide), 86.7 (d, JPC = 124.9 Hz, subs-Fcring-C1), 125.2 (s,
3
3
31
1
1
.45 (dd, JHH = 6.7 Hz, JPH = 13.7 Hz, 2H, C9H), 1.71 (m, C15), 127.8 (s, C14), 128.1 (s, C13), 142.1 (s, C12). P NMR
+
H, C11H), 3.92 (m, 2H, C10H), 4.26 (m, 7H, unsbs-Fcring over- (CD3OD): δ = 108.2. LC/MS: m/z 417.18 ([M–NH4] , 100%).
ꢀ
lapped with subs-Fcring C3H and C3 H), 4.57 (m, 2H, subs-Fcring
ꢀ
13
C2H and C2 H). C NMR (CD3OD): δ = 21.6 (s, C12), 24.3
Ammonium O–3-phenyl-1-propyl-(4-methoxyphenyl)
2
3
(
s, C11), 39.1 (d, JPC = 8.8 Hz, C9), 61.6 (d, JPC = 7.0 Hz,
dithiophosphonate, VI. 0.39 g (91%). m.p. 118°C. Anal. Calcd.
3
ꢀ
C10), 69.2 (d, JPC = 11.5 Hz, subs-Fcring-C3 and C3 coincide),
−1
for C16H22NO2PS2 (355.46 g · mol ): C, 54.06; H, 6.24; N, 3.94;
2
6
9.7 (s, unsubs-Fcring), 71.2 (d, JPC = 14.6 Hz, subs-Fcring-C2
1
S, 18.04; found: C, 54.22; H, 6.20; N, 3.89; S, 18.10%. H NMR
ꢀ
31
and C2 coincide), 86.7 (d, JPC = 125.3 Hz, subs-Fcring-C1).
NMR (CD3OD): δ = 103.3. LC/MS: m/z 369.20 ([M–NH4] ,
00%).
P
3
(
D2O): δ = 1.84 (m, 2H, C7H), 2.53 (t, JHH = 7.7 Hz, 2H,
+
C8H), 3.74 (m, 2H, –C6H), 3.76 (m, 3H, OCH3), 6.88 (A-part
1
4
of AA’MM’X, JPH = 2.7 Hz (JAX), N = JAM + JAM’ = 8.7 Hz,
3
2
H, m-H); 8.01 (M-part of AA’MM’X, JPH = 13.6 Hz (JMX),
3
Ammonium O-1-phenyl-1-propyl(ferrocenyl)
N = 8.70 Hz, 2H, o-H), 7.04 (d, JHH = 7.0 Hz, 2H, C10H), 7.13
3
3
dithiophosphonate], II. 0.57 g, 66%. m.p. 122–123°C. Anal. (t, JHH = 7.0 Hz, 1H, C12H), 7.20 (t, JHH = 7.3 Hz, 2H, C11H).
−1
13
Calcd. for, C19H24FeNOPS2 (433.35 g · mol ): C, 52.66; H, 5.58;
C NMR (D2O): δ = 31.8 (s, C7), 32.0 (s, C8), 55.4 (s, C5), 65.3
2 3
1
N, 3.23; S, 14.80. Found: C, 52.49; H, 5.57; N, 3.21; S, 14.75%. H (d, JPC = 7.8 Hz, C6), 113.5 (d, JPC = 14.9 Hz, C3), 125.8 (s,
3
2
NMR (CD3OD): δ = 0.74 (t, JHH = 7.3 Hz, 3H, –C11H), 1.9 (m, C12), 128.3 (s, C11), 128.5 (s, C10), 132.1 (d, JPC = 13.6 Hz,
3
diastereotopic protons, 2H, H–C10-H), 4.21 (m, 7H, unsubs- C6), 132.7 (d, JPC = 109.5 Hz, C1), 141.5 (s, C9), 161.6 (d,
ꢀ
4
31
FcringH overlapped with subs-Fcring-C3H and C3 H), 4.49 (s,
JPC = 2.9 Hz, C4). P NMR (D2O): δ = 105.1. LC/MS: m/z
ꢀ
+
H, subs-Fcring C2H), 4.42 (s, 1H, subs-Fcring C2 H), 5.43 (m, 340.00 ([M
–
4
NH ] , 100%).
1
1
(
13
H, C9H-), 7.20 (m, 5H, Ar–CH). C NMR (CD3OD): δ = 8.4
3
3
s, C11), 30.9 (d, JPC = 4.3 Hz, C10), 69.0 (d, JPC = 11.5 Hz,
Funding
3
ꢀ
subs-Fcring-C3), 69.1 (d, JPC = 11.5 Hz, subs-Fcring-C3 ), 69.6
2
(
(
8
(
1
7
s, unsubs-Fcring), 70.9 (d, JPC = 14.6 Hz, subs-Fcring-C2), 71.4 We gratefully acknowledge the financial assistance of The Scientific and
2
ꢀ
2
Technological Research Council of Turkey (grant number TBAG 114Z091)
and Ankara University Research Fund (Project No: 20050705094 and
d, JPC = 14.7 Hz, subs-Fcring-C2 ), 78.1 (d, JPC = 7.4 Hz, C9),
7.7 (d, JPC = 123.6 Hz, subs-Fcring-C1), 126.7 (s, C14), 127.2
1
3L4240009).
3
31
s, C13), 142.6 (d, JPC = 4.0 Hz, C12). P NMR (CD3OD): δ =
+
+
07.6. LC/MS: m/z 455.01 ([M+Na] , 6%), 416.03 ([M–NH4] ,
+
%), 298.95 ([FcPS2O+H] , 100%).
References
1
2
3
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Ammonium O-3-pentyl(ferrocenyl)dithiophosphonate], III.
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0
(
2
−1
385.31 g · mol ): C, 46.76; H, 6.28; N, 3.64; S, 16.64. Found:
1
C, 46.72; H, 6.20; N, 3.63; S, 16.55%. H NMR (CD3OD): δ =
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ꢀ
ꢀ
C3 H), 4.35 (m, 1H, C9H), 4.57 (m, 2H, subs-Fcring C2H and
13
3
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ꢀ
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(
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1
24.7 Hz, subs-Fcring-C1). 31P NMR (CD3OD): δ = 105.9.
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+
LC/MS: m/z 367.30 ([M–NH4] , 100%).
1
1
1
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1
1
1
1
1
1
dithiophosphonate], IV. 0.59 g, 69%. m.p. 122–12 3°C. Anal.
−
1
Calcd. for, C19H24FeNOPS2 (433.35 g · mol ): C, 52.66; H, 5.58;
1
N, 3.23; S, 14.80. Found: C, 52.55; H, 5.57; N, 3.18; S, 14.71%. H
2
281-2284.
NMR (CD3OD): δ = 1.85 (m, 2H, C10H), 2.65 (m, 2H, C11H),
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ꢀ
subs-Fcring C3H and C3 H), 4.59 (m, 2H, subs-Fcring C2H and
ꢀ
13
C2 H), 7.15 (m, 5H, Ar–CH). C NMR (CD3OD): δ = 31.9
3
3
(
s, C1), 32.3 (d, JPC = 8.6, C9), 62.8 (d, JPC = 7.0 Hz, C10),
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