Synthesis of (η6-arene)(η5-cyclopentadienyl) iron (II) complexes with heteroatom and carbonyl substituents Part II, Amino substituents

Article abstract of DOI:10.1016/j.jorganchem.2006.08.028

A variety of methods have been used in the synthesis of amino-substituted (η⁶-arene)(η⁵-cyclopentadienyl) iron(II) complexes. Conventional thermal ligand exchange of 2-fluoroaniline with ferrocene in the presence of Devarda's alloy gave an Ullmann coupling product, 2,2′ diaminobiphenyl complex, whereas omitting metal powder gave the 2-fluorobenzene complex. Double S_NAr substitution of the 1,2-dichlorobenzene complex by dimethylamine is reported. Microwave-assisted S_NAr reactions have led to the development of a one-pot synthesis of N-arylaminoacids. Acetylation of amino-complexes is described and the product anilide complexes used in S_NAr displacements to form aminoanilide analogues. Hexamethyldisilazane was found to be an efficient aminating agent in the presence of alcohols or phenols in DMSO, leading to the synthesis of the (η⁶-1,2-diaminobenzene)(η⁵-Cp) iron(II) complex, the first (ArFeCp)⁺ species reported containing two primary amino groups.

Full text of DOI:10.1016/j.jorganchem.2006.08.028

Journal of Organometallic Chemistry 691 (2006) 4926–4930
www.elsevier.com/locate/jorganchem
Synthesis of (g6-arene)(g5-cyclopentadienyl) iron (II) complexes
with heteroatom and carbonyl substituents
q
Part II, Amino substituents
R.M.G. Roberts
Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
Received 11 August 2006; accepted 11 August 2006
Available online 22 August 2006
Abstract
A variety of methods have been used in the synthesis of amino-substituted (g6-arene)(g5-cyclopentadienyl) iron(II) complexes. Con-
ventional thermal ligand exchange of 2-fluoroaniline with ferrocene in the presence of Devarda’s alloy gave an Ullmann coupling prod-
uct, 2,20 diaminobiphenyl complex, whereas omitting metal powder gave the 2-fluorobenzene complex. Double SNAr substitution of the
1,2-dichlorobenzene complex by dimethylamine is reported. Microwave-assisted SNAr reactions have led to the development of a one-pot
synthesis of N-arylaminoacids. Acetylation of amino-complexes is described and the product anilide complexes used in SNAr displace-
ments to form aminoanilide analogues. Hexamethyldisilazane was found to be an efficient aminating agent in the presence of alcohols or
phenols in DMSO, leading to the synthesis of the (g6-1,2-diaminobenzene)(g5-Cp) iron(II) complex, the first (ArFeCp)+ species reported
containing two primary amino groups.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Amino; Iron; Cyclopentadienyl; Synthesis
1. Introduction
can be synthesized using water as a solvent under mild con-
ditions [6]. This paper reports new synthetic routes to
amino-substituted (ArFeCp)+ complexes1 and includes
the preparation of 1,2-disubstituted species. No attempt
has been made to optimize yields in these reactions.
Synthesis of (g6-arylamino)(g5-cyclopentadienyl) iron-
(II) complexes (ArFeCp)+ is usually accomplished by either
direct ligand exchange [1] or by SNAr displacements, using
halobenzene complexes as the substrate and amines as
nucleophilic reagents [2]. Microwave-mediated ligand
exchange reactions have led to great reductions in reaction
times and in some cases increased yields [3]. SNAr reactions
by oxygen nucleophiles can result in double displacements
in dihalobenzene complexes [4]. For primary amines as
nucleophiles, however, only mono-substitution is observed
for 1,2-dichlorobenzene complexes [4], whereas disubstitu-
tion occurs for 1,4 analogues using piperazines as nucleo-
philes [5]. Recent work has shown that amino complexes
2. Results and discussion
2.1. Thermal ligand exchange reactions
These reactions proceed readily for most arylamines
according to
1
For structural formulae, these complexes are represented by
q
Part 1.
E-mail address: rogermgroberts@yahoo.com
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.08.028

R.M.G. Roberts / Journal of Organometallic Chemistry 691 (2006) 4926–4930
4927
This complex has been previously reported but with no
experimental details [8]. The reason for disubstitution in
this case is the lack of an acidic hydrogen on the N atom
in the intermediate mono substituted complex. Such a
hydrogen is present when primary amines are used as
nucleophiles and is easily removed in basic media to form
an electron rich conjugate base which inhibits further
nucleophilic substitution [4].
ð1Þ
However, a difficulty arises where X = F, particularly
where the fluorine is in the ortho position to the amino
group. Using Devarda’s alloy (DA) (50%Cu, 45%Al, and
5%Zn) 2-fluoroaniline, and 1,2,4-trichlorobenzene (TCB)
as solvent, Ullmann coupling reactions [7] dominate giving
a yield of 28% of the 2,2-diaminobiphenyl complex
SNAr reactions of (ArFeCp)+ complexes take place over
several hours and in some cases days. The use of micro-
wave radiation greatly accelerates the rates of these reac-
tions leading to SNAr displacements which do not occur
using conventional methods. Thus the diphenylamine com-
plex can be made in moderate yields by reaction of the flu-
orobenzene complex with aniline
ð2Þ
ð4Þ
The product exists as two diastereomeric forms due to the
enantiomeric nature of the moiety
The above technique was used to devise a one-pot synthesis
[9] of an arylated aminoacid in moderate yield
ð5Þ
and biphenyl isomerism. These isomers occur in a 3:1 ratio
though it is difficult to assign structure to them from 13C
NMR data. Normal Ullmann reactions are activated by
electron withdrawing substituents such as NO2 groups [7].
The [CpFe+] unit is equivalent to approximately two NO2
groups in its electron withdrawing power and activates even
fluorine substituents which are normally unreactive. The
fact that no coupling was observed for 2-fluoroaniline itself
under the above conditions for (2) testifies to this strong
activation.
The use of Al powder instead of DA resulted in mainly
the desired 2-fluoroaniline complex with ꢀ10% of the
coupling product. Omitting metal powder altogether, and
using a lower boiling solvent (80–100ꢁ pet. ether), the 2-flu-
oroaniline complex alone was formed in 42% yield. 4-Flu-
oroaniline gave much less coupling when metal powders
were used – a 3.5:1 mixture of the 4-fluoroaniline and
4,4-diaminobiphenyl complex was obtained with DA.
2.3. Activation of halo-aniline complexes to SNAr
substitution
Halo-aniline complexes do not normally undergo SNAr
displacements by nitrogen nucleophiles (vide supra). Acet-
ylation of the halo amino complexes provides an alterna-
tive route for delocalisation of the incipient lone pair of
the deprotonated complex, thus reducing electron donation
to the complexed arene thus lessening inhibition to nucleo-
philic substitution. The acetanilide complexes are readily
prepared and easily hydrolysed.
ð6Þ
2.2. SNAr displacements
Mono-substitution is usually observed in SNAr reactions
of dichlorobenzene complexes with primary amines [4].
However, for dimethylamine, it is possible to doubly sub-
stitute the 1,2-dichlorobenzene complex under mild condi-
tions using a very large excess of 40% aq. Me2NH.
This strategy enables SNAr reactions to be performed on
the intermediate anilide complex and the NH2 group to
be regenerated. Trifluoroacetylation should, of course, be
a much stronger electron attracting N-substituent, but
unfortunately is extremely sensitive to hydrolysis which
now dominates over the SNAr process. In passing, it is
worth noting that acetylation reactions can be monitored
easily from the Cp signals in 13C NMR spectra. For aniline
ð3Þ

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R.M.G. Roberts / Journal of Organometallic Chemistry 691 (2006) 4926–4930
complexes these signals lie in the range 75.3–76.6 ppm; for
haloaniline complexes, 78.0–79.4 ppm and for anilide com-
plexes, 79.9–80.4 ppm.
ð10Þ
The effect of acetylation in SNAr reactions is shown by
the fact that substitution occurs for the chloroacetanilde
complexes but not for the chloroaniline complexes
themselves.
The SNAr product in Eq. (7) shows a doubling of some
signals in the 13C NMR spectrum indicating the existence
of two isomeric species. From signal intensities, these iso-
mers are present in a 1:1 ratio and could occur due to
restricted rotation about both C–N bonds resulting in
cis/trans isomerism.
This reaction can be used (phenol replacing ethanol as the
ammonia forming reagent) to give a 14% yield of the 1,2-
phenylenediamine complex, isolated as a monohydrate.
This is the first example of an (ArFeCp)+ complex contain-
ing two primary amino groups. Thermal and photochemi-
cal ligand exchange involving 1,2-phenylenediamine itself
gave no product.
3. Conclusion
The reactions described here offer some alternative
routes to the synthesis of (g6-arylamine)(g6-Cp) iron(II)
complexes and hence by decomplexation [3,10] to new aryl-
amines, though decomplexation is more difficult for aryl-
amine complexes due to the dominant contribution of the
iminocyclohexadienyl mesomeric form to the structure
which strengthens iron-ligand bonding [6].
ð7Þ
Using ammonia as a nucleophile, SNAr substitution was
observed in the case of the 2-fluoroacetanilide complex
yielding the 2-aminoacetanilide analogue
4. Experimental
1H and 13C NMR were obtained using a JEOL EX270
spectrometer; chemical shifts, d, are in ppm relative to
TMS [s, single; d, doublet; tr, triplet for H NMR]. JCF
1
ð8Þ
coupling constants are in Hz. Solvents used were [2H]6-ace-
tone for PF6 salts and [2H]6-DMSO for BPh4 salts. For the
latter, the BPh4 signals are omitted in the interest of brev-
ity. CHN analyses were obtained from the Microanalytical
Laboratory, University of Manchester. Mass Spectra were
recorded using a Kratos MS 50 Double Focusing mass
spectrometer with an FAB source. Synthesis of (ArFeCp)+
complexes as starting materials followed microwave-medi-
ated techniques described in Ref. [1].
Interestingly, the 2-fluoroaniline complex gave a 40%
yield (as estimated from 13C NMR) of the 1,2-phenylenedi-
amine complex but was contaminated with starting mate-
rial which proved difficult to remove. A 6% yield of the
2-chloroaniline complex was obtained from reaction with
the 1,2-dichlorobenzene complex. The 1,3- and 1,4-dichlo-
robenzene complexes did not react which suggests activa-
tion by an ortho inductive effect. A 40% yield of the
4-aminoacetanilide complex was obtained by this method.
Hydrolysis of the 2-aminoacetanilide complex formed
above resulted in an inseparable mixture of the 1,2-pheny-
lenediamine and aniline complexes in a 3:1 ratio. The cause
of the de-amination is unclear but appears to be due to the
ortho nature of the substitution since the 1,4-phenylenedi-
amine complex can be prepared in 30% yield without this
complication.
4.1. Synthesis of (g6-2-fluoroaniline)
(g5-cyclopentadienyl) iron(II) hexafluorophosphate
Ferrocene (5.6 g, 0.030 mol) and AlCl3 (4.8 g, 0.036 mol)
were ground together and added to 80–100 ꢁC pet.ether
(10 ml). Flaked graphite (1.0 g) and 2-fluoroaniline (1.1 g,
0.010 mol) were added to the mixture. [NB: Al powder or
Devarda’s alloy were not used, see below]. After thorough
stirring, the mixture was microwaved for 4 min on a MED-
IUM setting in the apparatus described in Ref. [1]. After
careful quenching with ice, followed by the usual work-
up, 1.6 g (42%) of the desired product was obtained.
2.4. Hexamethyldisilazane (HMDS) as an aminating agent
3
2
Treatment of HMDS with alcohols or phenols produces
ammonia in accordance with
13CMR, d, 71.82, JCF 3.5 (C6); 76.54, JCF 17.6 (C3);
3
2
79.01, JCF 5.6 (C4); 84.83, (C5); 117.63, JCF 13.3 (C1);
1
124.84, JCF 272.9 (C2).
(Me3Si)2NH + 2ROH ! NH3 + 2Me3SiOR
ð9Þ
The synthesis of (g6-2,21-diaminobiphenyl)bis-[g5-
cyclopentadienyl iron(II) hexafluorophosphate] followed
the above procedure, except that Devarda’s alloy (12.4 g)
was added and TCB used as the solvent. The product
was obtained in 28% yield.
This reaction can be used to generate NH3 in situ as a
nucleophile for SNAr displacements. Thus reaction of the
chlorobenzene complex with HMDS gives an excellent
yield of the aniline complex.

R.M.G. Roberts / Journal of Organometallic Chemistry 691 (2006) 4926–4930
4929
CHN analysis: Found, C, 36.8; H, 3.1; N, 3.9%. Calcd.
for C22H22F12Fe2N2P2: C, 36.90; H, 3.10; N, 3.91. Using Al
powder (3.0 g 0.111 mol), a mixture of the 2-fluoraniline
complex and the above biphenyl complex was obtained in
a ratio of 10:1.
[(PhF)FeCp] PF6 (1 g, 2.8 mmol), glycine hydrochloride
ethylester (0.8 g 5.7 mmol) Et3N (1.0 g, 10 mmol), and
flaked graphite (2 g) in DMF (10 mls) were microwaved
for 5 min on a MEDIUM setting. t-BuOK (1.0 g,
8.9 mmol) was added, and the whole microwaved for a fur-
ther 3 min, then filtered into Et2O (200 ml) to give a ppt.
This was filtered off and the residue washed with MeOH
and leached into the ethereal filtrate. After further filtra-
tion, the Et2O extract was warmed with a little decolouris-
ing charcoal and filtered. The Et2O and DMF were
removed by rotary evaporation at 40 ꢁC and 95 ꢁC, respec-
tively. The brown residue was extracted with CH2Cl2
(100 ml) and washed with dist. H2O to remove residual
DMF. Evaporation gave an oil (0.20 g) whose 13C NMR
showed it to be N-phenylglycine of ꢀ95% purity. Yield:
43%.
The 13C NMR of the biphenyl complex showed a dou-
bling of signals suggesting two isomeric species. The shifts
for the main isomer (74%) only are reported, using conven-
tional numbering for the biphenyl system. 13C NMR, d,
71.17(C3), 81.17 (C5), 86.70 (C1), 86.84 (C4,C6), 126.14
(C2).
The corresponding reaction using 4-fluoroaniline and
Devarda’s alloy resulted in the formation of the 4-fluoroan-
iline complex and the 4,41-diaminobiphenyl complex in a
ratio of 3.5:1 13C NMR of the latter: d, 71.21(C3,5),
86.90 (C2,6), 89.74 (C1) 125.33 (C4).
6.2. Acetylation of aniline complexes
5. SNAr reactions
The following procedure was adopted for all acetyla-
tions. A solution of (g6-aniline)(g5-Cp) iron(II) PF6
(0.70 g 1.95 mmol) in acetic anhydride (5 g) was refluxed
for 0.5 h. After cooling, the mixture was poured into ether
(100 ml) to give yellow ppt. This was filtered off, washed
5.1. Synthesis of (g6-1,2-N-dimethylaminobenzene)
(g5-cyclopentadienyl) iron(II) PF6
(g6-1,2-Dichlorobenzene)(g5-Cp) iron(II)PF6 (1.0 g,
2.4 mmol) in CH2Cl2 (30 ml) was stirred at RT for three
days with 40% Me2NH(50 ml) in a stoppered flask. The
two layers were then separated and the aqueous phase
extracted with CH2Cl2 (3 · 25 ml). The combined CH2Cl2
extracts were dried (anhyd MgSO4), filtered and evapo-
rated to give 1.0 g orange-red oil. This was redissolved
in CH2Cl2 and chromatographed on neutral alumina to
give 0.32 g (30%) red-orange solid whose 13C NMR [dc,
40.66(Me), 74.77 (Cp), 75.80 (C3,6), 81.70 (C4,5)
117.12 (C1)] agreed well with calculated and literature
values [8].
1
with ether and air dried to give 0.60 g product (77%). H
NMR: d, 1.18s (CH3), 5.14 s (Cp), 6.26 tr (H4), 6.41d
(H2,6), 6.87 tr(H3,5). 13C: d, 24.40 (Me), 77.81 (Cp),
78.99 (C2,6), 85.71 (C4), 87.62 (C3,5), 111.60 (C1),
171.44 (CO). CHN analysis: Found: C, 38.62; H,3.50; N,
3.74%. Calcd. For C13H14F6Fe NOP: C, 38.93; H, 3.51;
N, 3.49. Mass spectrum Found 256.0: Calcd. 256.1 (loss
of H+).
The following acetylated aniline complexes were also
prepared (yields in parentheses) 4-chloroacetanilide
(84%): 13C NMR, d, 24.39 (Me), 78.33 (C2,4), 80.20
(Cp), 87.96 (C3,5), 104.69 (C4), 111.33 (C1), 171.47 (CO).
2-Methyl-3-chloroacetanilide (44%): 13C 18.80 (aryl Me),
24.37 (acetyl Me), 77.29, 77.36 (C6), 79.01, 79.09 (C2),
80.41 (Cp), 87.93 (C5), 99.99 (C4), 107.13 (C3), 110.83,
110.92 (C1), 171.49 (CO). 2-Fluoroacetanilide (75%): 13C,
6. Microwave-mediated SNAr reactions
6.1. Synthesis of (g6-diphenylamine)(g5-cyclopentadienyl)
iron(II) PF6
3
24.36 (Me), 77.48, JCF 19.9 (C3), 77.87 (C6), 79.23 (Cp)
3
2
84.02, JCF 6.0 (C4), 85.77 (C5), 102.64, JCF 11.9 (C1),
A mixture of (g6-fluorobenzene)(g5-Cp) iron(II) PF6
(1.0 g 2.8 mmol), aniline (0.6 g, 6.4 mmol). Et3N (1.0,
10 mmol), and flaked graphite (2 g) in dry DMF (10 ml)
was microwaved for 5 min. on a MEDIUM setting. The
mixture was filtered into Et2O (200 ml) and the residue lea-
ched with MeOH into the Et2O. The whole was cooled to
0 ꢁC overnight. The supernatant Et2O was then decanted
off and the residue triturated with a further portion of ether
then extracted with CH2Cl2 (50 ml). After filtration, the fil-
trate was washed with 5% aq. NaOH, separated, dried
(MgSO4), filtered and evaporated to give 0.52 g orange-
brown solid whose IR spectrum was identical to the desired
product. Yield: 33%.
1
129.37, JCF271.3 (C2), 171.68 (CO). 4-Fluoroacetanilide:
CHN analysis: Found: C, 36.6; H, 3.2; N, 3.0%. Calcd.
For C13H13F7FeNOP: C, 37.32; H, 3.13; N, 3.34.
6.3. Hydrolysis of anilide complexes
(g6-Acetanilide)(g5-Cp) iron(II) PF6 (1.0 g 2.5 mmol)
was added to 0.18 M H2SO4 (20 ml) and the whole
refluxed for 2.5 h. The mixture was filtered, cooled in
ice, and 10% NaOH (15 ml) added dropwise. After filtra-
tion, an aq. solution of 0.26 M NaBPh4 (10 ml) was added
and the resultant ppt. filtered off, washed with dist. H2O
and dried at 85 ꢁC for 2 h to give the aniline complex
(0.89 g 67%).
The above method was used to devise a one-pot synthe-
sis of an N-arylated aminoacid.

4930
R.M.G. Roberts / Journal of Organometallic Chemistry 691 (2006) 4926–4930
7. SNAr displacements in halo-acetanilide complexes
plex gave a 40% yield of the 4-aminoacetanilide complex.
Hydrolysis of the 2-aminoacetanilide complex by 0.2 M
H2SO4 gave an inseparable mixture of the 1,2-phenylenedi-
amine and aniline complexes in a 3:1 ratio. Similar hydro-
lysis of the 4-aminoacetanilide complex gave a 30% yield of
the 1,4-phenylenediamine complex.
7.1. [g6-4-(Ethylglycinylacetanilide)](g5-cyclopentadienyl)
iron(II) BPh4
Glycine hydrochloride ethylester (4.2 g, 30.0 mmol) was
dissolved in dry DMSO (10 ml.) and Et3N (4.0 g,
39.6 mmol) added. The resultant ppt. of Et3N. HCl was fil-
tered off and dry THF (10 ml) added to the filtrate followed
by further filtration. (g6-4-Chloroacetanilide)(g5-Cp) iron-
(II) PF6 (0.9 g 2.0 mmol) was added and the mixture
refluxed overnight, excluding moisture. On cooling, CH2Cl2
(25 ml) was added and the whole filtered. The filtrate was
rotary evaporated at 55 ꢁC to remove CH2Cl2 and THF
and the resulting brown red solution was washed with
Et2O (3 · 50 ml). The brown residue was extracted with
CH2Cl2 filtered and re ppted. with Et2O. The oily sludge
was taken up in MeOH (20 ml) and added dropwise to
aq. 0.15 M NaBPh4 (20 ml). The MeOH was removed by
rotary evaporation and the resultant mixture extracted with
CH2Cl2, dried, and evaporated to give a brown oil (1.4 g)
This was chromatographed on neutral alumina eluting with
acetone to give a yellow-orange solid (0.25 g, 20%). 13C
NMR, d, 14.45 (CH3CH2–), 24.23, 24.26 (CH3CO–),
44.86, 44.97 (–NHCH2–), 62.00 (–CH2OCO–), 66.85 (C3),
76.67, 76.76 (C2), 77.33 (Cp), 105.59, 105.68 (C1), 123.79,
123.85 (C4) 170.30 (–CO2–), 170.86, 170.92 (CH3CO–)
Mass spectrum; found 357.1: Calcd 357.2
1H NMR: 4.60 (Cp), 5.43 (H2,3,4,6), 5.56 (NH2). 13C
NMR 67.33 (C2,3,5,6), 75.56 (Cp), 119.56 (C1,4).
CHN analysis: Found C, 76.10; H, 6.08; N, 4.83%.
Calcd. for C35H33BFeN2: C, 76.67; H, 6.07; N, 5.11.
7.3. Hexamethyldisilazane (HMDS) as an arninating
reagent
A solution of (g6-chlorobenzene)(g5-cyclopentadienyl)
iron(II) PF6(0.5 g, 1.3 mmol) ethanol (0.6 ml, 10 mmol),
and HMDS (1.0 ml. 4.7 mmol) in dry DMSO (3 ml) was
heated at 70 ꢁC for 0.5 h using a condenser. After cooling
to RT, the mixture was added to aq. 0.05 M NH4PF6
(50 ml). The orange-yellow ppt. was filtered off, washed
with cold dist H2O and Et2O then air dried to give 0.29 g
product. Extraction of the aqueous layer with CH2Cl2
(100 ml) gave a further 0.07 g. Total yield 77%.
A cognate synthesis using (g6-2-fluoroaniline)(g5-cyclo-
pentadienyl) iron(II) PF6 but replacing ethanol with phe-
nol, gave a 14% yield of the 1,2-phenylenediamine
complex as a monohydrate 13C NMR 70.74 (C3,6), 75.22
(Cp), 77.65 (C4,5), 109.00 (C1,2).
A similar reaction using the 2-chloroacetanilide complex
gave a mixture of the 2-[ethylglycinyl] aniline (47%) and 2-
[ethylglycinyl] acetanilide (17%) complexes. The 2-chloro-
aniline complex gave no reaction.
CHN analysis: Found C, 74.9; H, 6.1; N, 4.7%. Calcd.
for C35H35BFeN2O: C, 74.23; H, 6.23; N, 4.95.
Acknowledgements
7.2. (g6-2-Aminoacetanilide)(g5-cyclopentadienyl) iron(II)
tetraphenylborate
The author thank the University of Essex for laboratory
facilities and Mr. R.J. Ranson and Mr. N. Barnard for
NMR and mass spectra respectively.
A slurry of (g6-2-fluoroacetanilide)(g5-Cp) iron(II) PF6
(0.5 g, 1.2 mmol) in conc. [NH4][OH] (40 ml) was refluxed
for 1.5 h with stirring, then filtered and the orange filtrate
evaporated to dryness. The yellow residue was extracted
with acetone (15 ml) and filtered into ice-cold aq. 0.04 M
NaBPh4 (25 ml). The flocculent yellow ppt. was filtered
off, washed with a little dist. H2O then dried at 60 ꢁC to
give 0.35 g yellow solid. (50%) whose IR showed the pres-
ence of H2O.
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13C, 23.86 (Me), 71.95, (C3), 76.35, 76.52 (C6), 77.15,
77.59 (Cp) 79.84, 80.09 (C5), 83.94, 84.57 (C4), 91.43
(C1), 119.35 (C2), 171.06, 171.15 (CO). CHN analysis:
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iline complex, partial substitution occurred giving a 40%
yield of the 1,2-phenylenediamine complex admixed with
starting material. However, it was not possible to separate
the two materials by column chromatography.
´
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The 1,2-dichlorobenzene complex gave a 6% yield of the
2-chloroaniline complex, but the 1,3- and 1,4-dichloroben-
zene complexes did not react. The 4-fluoroacetanilide com-