Synthesis and reactions of new 1,2- and 1,3-cyclopentadienyl disubstituted cobalt sandwich compounds (η5-C5H3R 2)Co(η4-C4Ph4) (RCH 2OH, CHO, CCH, CH2N3, CH2NH 2, CH2OAc, CHNPh)

Article abstract of DOI:10.1016/j.jorganchem.2012.07.023

Synthesis and characterization of a series of 1,3- and 1,2-cyclopentadienyl disubstituted derivatives of η⁵-C_pCo(η ⁴-C₄Ph₄) has been described. The 1,3- and 1,2-cyclopentadienyl diester derived cobalt sandwich compounds {η⁵-C₅H₃[C(O)OMe]₂} Co(η⁴-C₄Ph₄) were prepared by literature procedure and were separated by column chromatography. The reduction of these diester derivatives using LiAlH₄ gave the bis(hydroxymethyl) derivatives, [1,3-η⁵-C₅H₃(CH ₂OH)₂] Co(η⁴-C₄Ph₄) 1 and [1,2-η⁵-C₅H₃(CH₂OH) ₂]Co(η⁴-C₄Ph₄) 2 which were oxidized to the dialdehydes [1,3-η⁵-C₅H ₃(CHO)₂]Co(η⁴-C₄Ph₄) 3 and [1,2-η⁵-C₅H₃(CHO)₂] Co(η⁴-C₄Ph₄) 4 by using tetrapropylammonium perruthenate along with N-methyl morpholine oxide. Reaction of the dialdehydes with (chloromethyl)triphenylphosphonium chloride/n-BuLi followed by elimination of HCl using n-BuLi resulted in the 1,2- and 1,3-cyclopentadienyl disubstituted dialkynes [1,3-η⁵-C₅H₃(CCH) ₂]Co(η⁴-C₄Ph₄) 5 and [1,2-η⁵-C₅H₃(CCH)₂] Co(η⁴-C₄Ph₄) 6. The reactions of 1 and 2 with NaN₃ in acetic acid resulted in the bis(azidomethyl) derivatives [1,3-η⁵-C₅H₃(CH₂N ₃)₂]Co(η⁴-C₄Ph₄) 7 and [1,2-η⁵-C₅H₃(CH₂N ₃)₂]Co(η⁴-C₄Ph₄) 8. Heating of bis(hydroxymethyl) compounds 1 and 2 in acetic acid at 85-90 °C resulted in the formation of bis(2-acetoxymethyl) derivatives [1,3-η⁵-C₅H₃(CH₂OAc) ₂]Co(η⁴-C₄Ph₄) 9 and [1,2-η⁵-C₅H₃(CH₂OAc) ₂]Co(η⁴-C₄Ph₄) 10. The reactions of 1 and 2 with thiophenol in the presence of trifluoroacetic acid in dichloromethane gave bis(phenylmethyl thioether) derivatives 11 [1,3-η⁵-C₅H₃(CH₂SPh) ₂]Co(η⁴-C₄Ph₄) and [1,2-η⁵-C₅H₃(CH₂SPh) ₂]Co(η⁴-C₄Ph₄) 12. The click reaction of the 1,2-dialkyne 6 with benzyl azide resulted in the 1,2-bis(triazole) derivative 13. The 1,3-diazide 8 was reduced to bis(aminomethyl) derivative [1,3-η⁵-C₅H ₃(CH₂NH₂)₂]Co(η⁴- C₄Ph₄) 14. Condensation of the 1,3-dialdehyde 3 with aniline resulted in the 1,3-bis(phenylimino) derivative 15. All the new compounds synthesized in this study were characterized by ¹H and ¹³C NMR, FT-IR, HRMS, CHN analysis. The compounds 2-6, 8 and 10 have also been structurally characterized by single crystal X-ray diffraction analysis.

Full text of DOI:10.1016/j.jorganchem.2012.07.023

Journal of Organometallic Chemistry 717 (2012) 99e107
Contents lists available at SciVerse ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis and reactions of new 1,2- and 1,3-cyclopentadienyl disubstituted cobalt
sandwich compounds (h h
5-C5H3R2)Co( 4-C4Ph4) (R]CH2OH, CHO, C^CH, CH2N3,
CH2NH2, CH2OAc, CH]NPh)
*
Nem Singh, Bhanu P.R. Metla, Anil J. Elias
Department of Chemistry, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110016, India
a r t i c l e i n f o
a b s t r a c t
Synthesis and characterization of a series of 1,3- and 1,2-cyclopentadienyl disubstituted derivatives of h5
-
Article history:
CpCo(
compounds {
rated by column chromatography. The reduction of these diester derivatives using LiAlH4 gave the
bis(hydroxymethyl) derivatives, [1,3- and [1,2-
5-C5H3(CH2OH)2] Co( 4-C4Ph4) 5-C5H3(CH2OH)2]
Co(
4-C4Ph4) 2 which were oxidized to the dialdehydes [1,3- 5-C5H3(CHO)2]Co( 4-C4Ph4) 3 and [1,2-h5
C5H3(CHO)2]Co(
4-C4Ph4) 4 by using tetrapropylammonium perruthenate along with N-methyl mor-
h
4-C4Ph4) has been described. The 1,3- and 1,2-cyclopentadienyl diester derived cobalt sandwich
Received 31 May 2012
Received in revised form
9 July 2012
h
5-C5H3[C(O)OMe]2}Co( 4-C4Ph4) were prepared by literature procedure and were sepa-
h
Accepted 16 July 2012
h
h
1
h
h
h
h
-
Keywords:
h
Cyclopentadienyl
Cyclobutadiene
Cobalt
bis(hydroxymethyl)
bis(azidomethyl)
pholine oxide. Reaction of the dialdehydes with (chloromethyl)triphenylphosphonium chloride/n-BuLi
followed by elimination of HCl using n-BuLi resulted in the 1,2- and 1,3-cyclopentadienyl disubstituted
dialkynes [1,3-
of 1 and 2 with NaN3 in acetic acid resulted in the bis(azidomethyl) derivatives [1,3-
Co(
4-C4Ph4) 7 and [1,2- 5-C5H3(CH2N3)2]Co( 4-C4Ph4) 8. Heating of bis(hydroxymethyl) compounds 1
and 2 in acetic acid at 85e90 ꢀC resulted in the formation of bis(2-acetoxymethyl) derivatives [1,3-h5
C5H3(CH2OAc)2]Co(
4-C4Ph4) 9 and [1,2- 5-C5H3(CH2OAc)2]Co( 4-C4Ph4) 10. The reactions of 1 and 2
with thiophenol in the presence of trifluoroacetic acid in dichloromethane gave bis(phenylmethyl thi-
oether) derivatives 11 [1,3-
5-C5H3(CH2SPh)2]Co( 4-C4Ph4) and [1,2- 5-C5H3(CH2SPh)2]Co( 4-C4Ph4) 12.
The click reaction of the 1,2-dialkyne 6 with benzyl azide resulted in the 1,2-bis(triazole) derivative 13.
The 1,3-diazide 8 was reduced to bis(aminomethyl) derivative [1,3-
5-C5H3(CH2NH2)2]Co( 4-C4Ph4) 14.
h
5-C5H3(C^CH)2]Co(
h
4-C4Ph4) 5 and [1,2-
h
5-C5H3(C^CH)2]Co(
h
4-C4Ph4) 6. The reactions
5-C5H3(CH2N3)2]
h
h
h
h
-
h
h
h
h
h
h
h
h
h
Condensation of the 1,3-dialdehyde 3 with aniline resulted in the 1,3-bis(phenylimino) derivative 15. All
the new compounds synthesized in this study were characterized by 1H and 13C NMR, FT-IR, HRMS, CHN
analysis. The compounds 2e6, 8 and 10 have also been structurally characterized by single crystal X-ray
diffraction analysis.
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
Recently there has been a surge of activity in preparing such
bidentate ligands using stable metal sandwich compounds, espe-
Aryl rings with functional groups at the 1,2 and 1,3 positions and
heteroaryl rings with functional groups flanking the heteroatom
are excellent precursors for preparing a wide variety of chelating
and multidentate ligands. The classic examples for such bidentate
ligands are the chiral box (bis oxazoline) ligands which, along with
metal compounds have been used extensively in asymmetric
catalysis [1e5]. Achiral bidentate ligands have also been prepared
from 1,2 to 1,3-disubstituted aryl rings, the latter being used
extensively for the preparation of pincer type complexes [6e8].
cially with ferrocene as the substrate [9e14]. 1,2- and 1,3-
disubstitution of a Cp ring of ferrocene can be achieved with rela-
tive ease and many examples of multiple phosphine, amine and
heterocycle derived ferrocenes are available in the literature
[15e19]. Such compounds have shown promising activity in diverse
areas such as antitubercular agents, as receptors for recognition of
barbiturates and glucose sensors [20e22]. Apart from realizing
bidentate ligands, the ferrocene scaffold has also been derivatized
with terminal alkyne units at the 1 and 2 positions to prepare novel
alkyne linked multiferrocenyl assemblies [23e28].
Among non-ferrocenyl, highly stable and easily accessible
sandwich compounds, (
erable interest especially for the synthesis of chiral and sterically
h h
5-Cp)Co( 4-C4Ph4) has attracted consid-
* Corresponding author. Tel.: þ91 11 26591504.
E-mail address: eliasanil@gmail.com (A.J. Elias).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.07.023

100
N. Singh et al. / Journal of Organometallic Chemistry 717 (2012) 99e107
bulky derivatives [29e38]. Unlike ferrocene, only a handful of
yields of the bis(hydroxymethyl) derivatives 1 and 2. These were
readily converted to the dialdehydes 3 and 4 by catalytic amounts
of tetrapropylammonium perruthenate along with N-methyl mor-
pholine oxide as oxidant (Schemes 1 and 2), a method which results
in high yields of the aldehyde [38].
Reaction of the dialdehydes 3 and 4 with (chloromethyl)tri-
phenylphosphonium chloride/n-BuLi followed by elimination of
HCl by n-BuLi resulted in the 1,2 and 1,3 Cp disubstituted dialkynes,
5 and 6 [38]. The bis(hydroxymethyl) derived cobalt sandwich
compounds 1 and 2 were converted to bis(azidomethyl) derivatives
7 and 8 by the reaction with NaN3 in acetic acid at 50 ꢀC, similar to
the procedure reported by Francisco and coworkers for the
synthesis of azidomethylferrocene [43].
examples having 1,2 and 1,3-disubstitution on the Cp ring of
(h h
5-Cp)Co( 4-C4Ph4) has been reported so far and most of these
have methyl group as one of the Cp substituents which limits their
usefulness as bidentate ligands [39e41]. Recently, using methyl
chloroformate, we have reported an easy way of synthesizing
the 1,2- and 1,3-cyclopentadienyl diester derivatives of (
h
5-Cp)
Co(h
4-C4Ph4). A chiral 1,3-bis(oxazoline) and a 1,2-acenequinone
having both iron and cobalt sandwich units in the molecule were
also prepared from the diesters [42]. In this paper we report the
easy synthesis and characterization of a range of hitherto unknown
1,2- and 1,3-difunctional derivatives of this cobalt based sandwich
compound (h h
5-Cp)Co( 4-C4Ph4).
Interestingly the reactions of 1 and 2 in acetic acid at 85e90 ꢀC
resulted in bis(2-acetoxy methyl) derivatives 9 and 10 [44]. A
modified procedure reported for the synthesis of thioglycosylated
ferrocene was used to convert the bis(hydroxymethyl) derivatives 1
and 2 to the bis(phenyl thioether) derivatives 11 and 12 [43]. Our
reaction using phenyl mercaptan and trifluoroacetic acid was
considerably faster and was completed in 5 min instead of the 2 h
reported for the thioglycosylated ferrocene. Click reaction of the
1,2-dialkyne 6 with benzyl azide resulted in the 1,2-bis(triazole)
derivative 13. The 1,3-bis(azidomethyl) derivative 8 was readily
reduced to amino methyl derivative 14 by LiAlH4 in refluxing THF
[45]. A novel 1,3-bis(phenylimino) derivative 15 was also prepared
in quantitative yield by condensation reaction of aldehyde 3 with
aniline using toluene as solvent.
2. Results and discussion
Recently we have reported the synthesis of a palladium complex
based on the bidentate 1,3-bis oxazoline derived
(h
5-Cp)
Co(h
4-C4Ph4) which has been found to be an excellent catalyst
for conversion of achiral trichloroacetimidates to chiral tri-
chloroacetamides in good enantiomeric excess [42]. This finding
prompted us to explore the possibility of preparing analogous
cyclopentadienyl disubstituted derivatives of (h h
5-Cp)Co( 4-C4Ph4)
with a range of functionalities which can function as bidentate
ligands or can be precursors for realizing the same.
The reduction of 1,2- and 1,3-cyclopentadienyl diester derived
cobalt sandwich compounds with LiAlH4 gave almost quantitative
O
O
Ph
Ph
MeO2C
Ph
CO2Me
Ph
O
O
N
N
Co
Ph
Co
Ph
Ph
Co
Ph
Ph
Ph
Ph
Ph
15 98%
Ph
Ph
H
O
O
9 95%
C
C
°
CH 3
0
PhNH2/Toluene
Reflux, 1 h
9
-
5
LiAlH4/ THF
HOH2C
8
N3H2C
Ph
CH2N3
Ph
CH2OH
Ph
OHC
Ph
CHO
Ph
N-methyl morpholine
N-Oxide/Tetrapropyl
Co
Co
Ph
Co
NaN3/ CH3COOH,
50 °C
amm. perruthenate
Ph
Ph
Ph
Ph
Mol. sieves 4Å
Ph
92%
3
Ph
7 95%
1 97%
LiAlH4/ THF
Reflux
PhSH / TFA
Ph3P
CH2Cl2, 5 min
Cl
n-BuLi
H2NH2C
Ph
CH2NH2
PhSH2C
Ph
CH2SPh
Ph
Co
Ph
Co
Ph
Ph
Co
Ph
Ph
Ph
Ph
Ph
14 91%
Ph
11 92%
5
45%
Scheme 1. Synthesis and reactions of 1,3-bis(hydroxymethyl) derived (h h
5-Cp)Co( 4-C4Ph4).

N. Singh et al. / Journal of Organometallic Chemistry 717 (2012) 99e107
101
O
O
O
CO2Me
CO2Me
O
Ph
Co
Ph
Ph
Co
Ph
Ph
Ph
Ph
Ph
H
°
L
O
i
A
O
C
l
10 96%
C
3
H
4
H
/
90
-
T
C
H
85
F
CHO
CH2N3
CH2OH
CH2OH
CHO
CH2N3
N-methyl morpholine
N-oxide/Tetrapropyl
amm. perruthenate
Ph
Co
NaN3 / CH3COOH,
50 °C
Ph
Ph
Co
Ph
Ph
Co
Ph
Ph
Ph
Mol. sieves 4A
Ph
Ph
Ph
Ph
4
91%
2
96%
8 94%
PhSH / TFA
Ph3P
CH2Cl2, 5 min
n-BuLi
Cl
N
N
N
Ph
N
CH2SPh
CH2SPh
N
N
PhCH2N3
Ph
Co
Ph
Ph
Ph
Ph
Co
Co
Ph
Ph
Ph
Click Reaction
Ph
12 94%
Ph
Ph
Ph
Ph
13 78%
6
42%
Scheme 2. Synthesis and reactions of 1,2-bis(hydroxymethyl) derived (h h
5-Cp)Co( 4-C4Ph4).
2.1. Spectral studies
2.2. Structural studies
The 1H NMR spectrum of 1,2- and 1,3-cyclopentadienyl
disubstituted compounds 1e15 showed two peaks indicating
the presence of two unequal sets of protons on the cyclo-
pentadienyl ring. The spectral data of compounds 1e6 is mostly in
accord with analogous cyclopentadienyl monosubstituted deriv-
The crystal structure of the 1,2-bis(hydroxymethyl) derivative 2
indicated the two OH groups pointing away from the bulky C4Ph4
unit. Although no intramolecular hydrogen bonding was observed
in its crystal structure, weak OeH$$$O intermolecular hydrogen
ꢀ
bonding between hydroxyl groups with HeO$$$O distance 2.837 A
atives of
(
h
5-Cp)Co(
h
4-C4Ph4) as reported by Richards and
and OeH$$$O angle 165ꢀ were observed linking two molecules into
a dimer (Fig. 1).
coworkers [38].
The bis(azidomethyl) derivatives 7 and 8 are the first examples
of such disubstituted derivatives on a metal sandwich compound.
In the 1H NMR spectra of both 7 and 8, the CH2 hydrogens were
found to be diastereotopic showing two doublets in the range of
The crystal structures of dialdehydes 3 and 4 are given in
Figs. 2 and 3. The structure of 3 shows one of the two different
molecules present within the asymmetric unit. In both the
compounds, the aldehyde moiety was found to be coplanar with
the cyclopentadienyl ring and the exocyclic CeC bond was found
to show partial double bond character with bond distances in the
3.44e3.70 ppm, (2JCeH
¼
13.5 Hz). The infrared spectra of
compounds 7 and 8 showed strong azide vibrational bands at 2095
and 2102 cmꢁ1 respectively. Although 1, 2-Cp substituted diacetate
is known for ferrocene [50] no example of 1,3-Cp substituted
diacetates of sandwich compounds are known so far. The diaster-
eotopic CH2 protons of 9 and 10 were found to be further
ꢀ
range of 1.445(8) to 1.465(7) A. Although 1,2- and 1,3-dialkynyl
derived ferrocene and CpMn(CO)3 compounds are known [46],
crystal structures of terminal dialkyne derived sandwich
compounds have not been reported so far.
2
deshielded (4.37e4.54 ppm, JCeH ¼ 12.0 Hz). Compounds 11 and
The bond angles of the alkynyl group in compounds 5 and 6
(Figs. 4 and 5) were appearing in the range of 177.5(5) to 179.1(7)ꢀ
which were similar to the bond angle [178.1(3)ꢀ] of the alkynyl
group in the crystal structure of monoalkynyl cobalt sandwich
12 are the first examples of phenylthiomethyl derivatives of
(h h
4-Cp)Co( 4-C4Ph4). The diastereotopic CH2 protons of these
compounds were found to be shielded compared to azidomethyl
2
and acetate derivatives (3.10e3.37 ppm, JCeH ¼ 13.5 Hz). For the
compound [h h
5-(C5H4(C^CH)]Co( 4-C4Ph4) [35]. These values were
novel 1,3-bis(phenylimino) derivative 15, the imino hydrogens
were found to be deshielded as expected and were observed at
7.75 ppm.
also found to be closer to the alkynyl bond angles reported for
cyclopentadienyl 1,2 and 1,3-bis(trimethylsilylalkynyl) derived
CpMn(CO)3 compounds [46].

102
N. Singh et al. / Journal of Organometallic Chemistry 717 (2012) 99e107
Fig. 1. ORTEP diagram of 2 (showing intermolecular hydrogen bonding) with thermal ellipsoids at the 30% probability level. Phenyl hydrogen atoms have been omitted for clarity.
ꢀ
ꢀ
Selected bond lengths (A), Co(1)eC(1) 2.072(3), O(1)eC(10) 1.431(4), C(1)eC(2) 1.425(4), C(2)eC(3) 1.419(4), C(1)eC(10) 1.500(5). Selected bond angles ( ) O(1)eC(10)eC(1)
109.2(3), C(2)eC(1)eC(10) 127.9(3), C(5)eC(1)eC(10) 125.0(3).
The structure of the 1,2-bis(azidomethyl) derivative 8 (Fig. 6) is
the first crystal structure of an azidomethyl substituted metal
sandwich compound. The two azidomethyl groups are oriented
away from each other and the NeNeN angles are almost linear in
the range of 171.8(7) to 173.4(6)ꢀ. Although cyclopentadienyl 1,2-
bis(2-acetoxymethyl) derived ferrocene is known [47], analogous
were readily converted to bis(2-acetoxymethyl), bis(azidomethyl)
and bis(phenylthiomethyl) derivatives in very high yields. Both
bis(hydroxymethyl) derivatives were also oxidized to dialdehydes
using tetrapropylammonium perruthenate/N-methyl morpholine
ꢀ
N-oxide in the presence of molecular sieves 4 A in 90e91% yields.
The first examples of 1,2- and 1,3-Cp derived terminal dialkynes of
derivatives were so far unknown for (
h
4-Cp)Co(
h
4-C4Ph4). The
(h h
5-Cp)Co( 4-C4Ph4) were prepared using these dialdehydes as
crystal structure of compound 10 (Fig. 7) shows the two acetox-
ymethyl groups oriented upwards away from the bulky C4Ph4 unit.
precursors in 42e45% yields. Click chemistry was used successfully
to convert the 1,2-dialkyne derivative 6 to 1,2-triazole derivative 13.
The 1,3-dialdehyde was also converted to a novel bis(phenylimino)
derivative in good yield. All the new compounds reported are
highly stable to air and moisture and are precursors for the
synthesis of a range of basal bulky bidentate chiral and achiral
ligands with potential applications in catalysis.
3. Conclusions
The first synthesis and characterization of 1,2- and 1,3-
difunctional derivatives of the cobalt sandwich compound, (h5
-
Cp)Co(
C^CH, CH2N3, CH2SPh, CH2OAc, CH2NH2, CH]NPh has been
described. 1,2- and 1,3-bis(hydroxymethyl) compounds
h5
C5H3(CH2OH)2]Co(
4-C4Ph4) prepared from 1,2- and 1,3-
h
4-C4Ph4) with functional groups such as CH2OH, CHO,
4. Experimental
[
-
h
4.1. General procedures
cyclopentadienyl diester derived cobalt sandwich compounds
All manipulations were carried out using standard Schlenk
techniques under a nitrogen atmosphere. THF and xylene were
freshly distilled from sodium benzophenone ketyl and hexane was
distilled and dried over sodium and used. [(1,3-dicarbomethoxy)
h
5-cyclopentadienyl]
[(1,2-dicarbomethoxy)
(
h
h
4-tetraphenylcyclobutadiene)cobalt and
5-cyclopentadienyl]( 4-tetraphenylcyclo-
h
butadiene)cobalt [42] were prepared according to reported proce-
dures. Diphenylacetylene, triphenylphosphine, dicyclopentadiene
and methyl chloroformate procured from Aldrich were used as
such. 1H and 13C{1H} spectra were recorded on a Bruker Spectrospin
DPX-300 NMR spectrometer at 300 and 75.47 MHz respectively. IR
spectra in the range 4000e250 cmꢁ1 were recorded on a Nicolet
Protége 460 FT-IR spectrometer as KBr pellets. Elemental analyses
were carried out on a Carlo Erba CHNSO 1108 elemental analyzer.
Mass spectra were recorded in the EI and TOF mode using a JEOL SX
102/DA-6000 and MALDIeTOF Q-Star Micromass.
4.2. X-ray crystallography
The crystal structures of the 2e6, 8 and 10 were obtained by
slow evaporation of their respective solutions in a mixture of
hexane/ethylacetate. The compounds 2, 5, 6, 8 and 10 were found to
crystallize in the monoclinic system, compounds 3, 4 crystallized in
triclinic and orthorhombic crystal lattices respectively. The data
was collected using Bruker AXS SMART Apex CCD diffractometer.
Fig. 2. ORTEP diagram of 4 with thermal ellipsoids at the 50% probability level. Phenyl
hydrogen atoms have been omitted for clarity. Selected bond lengths (A), Co(1)eC(1)
2.072(3), Co(1)eC(6) 1.993(3), O(1)eC(10) 1.431(4), C(1)eC(2) 1.425(4), C(2)eC(3)
1.419(4), C(1)eC(10) 1.500(5). Selected bond angles (ꢀ), O(2)eC(11)eC(2) 114.4(3),
C(2)eC(1)eC(10) 127.9(3), C(5)eC(1)eC(10) 125.0(3), C(1)eC(2)eC(11) 128.3(3), C(3)e
C(2)eC(1) 107.5(3).
ꢀ

N. Singh et al. / Journal of Organometallic Chemistry 717 (2012) 99e107
103
Fig. 3. ORTEP diagram of 3 with thermal ellipsoids at the 30% probability level (two molecules in asymmetric unit). Phenyl hydrogen atoms have been omitted for cꢀlarity. Selected bond
ꢀ
lengths (A), O(1)eC(10) 1.199(6), O(2)eC(11) 1.114 (10), C(1)eC(2) 1.418(6), C(2)eC(3) 1.396(7), C(1)eC(10) 1.465(7), C(3)eC(11) 1.465(8). Selected bond angles ( ), O(1)eC(10)eC(1)
122.7(6), C(2)eC(1)eC(10) 124.7(5), C(2)eC(3)eC(4) 108.8(5), C(6)eC(7)eC(8) 89.8(3).
All the crystal structures were solved and refined using the
SHELXTL (version 6.12) software [48e51]. The ORTEP diagrams for
all the crystals 2e6, 8 and 10 are shown in the Figs. 1e7 respec-
tively. Data collection and structure refinement parameters of
crystals 2e6, 8 and 10 are given in Table 1. The relatively higher but
acceptable R factors of compounds 4, 5 and 10 which could not be
improved after repeated attempts are possibly the consequence of
room temperature data collection.
brs, OH), 3.97e4.10 (4H, m, CH2), 4.53 (2H, s, CpH), 4.69 (1H, s, CpH),
7.23e7.25 (12H, m, m/p-PhH), 7.41e7.45 (8H, m, o-PhH). 13C NMR (
75 MHz, CDCl3): 59.20 (CH2), 74.98 (C4Ph4), 79.39, 81.94, 98.66
(CpC), 126.76, 128.36, 128.47, 135.85 (PhC). HRMS: Calcd. for
C35H29O2CoNa: 563.1397, found 563.1395.
d,
4.4. Preparation of [
h
h
5-1,2-(CH2OH)2C5H3]Co( 4-C4Ph4) (2)
{
h
5-1,2-[MeOC(O)]2C5H3}Co(
h
4-C4Ph4) (2.39 g, 4.00 mmol) was
4.3. Preparation of [
h
5-1,3-(CH2OH)2C5H3]Co(
h
4-C4Ph4) (1)
taken in an identical reaction by which 1 was synthesized to
prepare 2. Yield: 2.08 g, 3.85 mmol, 96%. Mp: 201e203 ꢀC. Anal.
Found: C, 77.89; H, 5.32. Calcd. for C35H29O2Co: C, 77.77; H, 5.41. IR
{h
5-1,3-[MeOC(O)]2C5H3}Co(
h
4-C4Ph4) (2.39 g, 4.00 mmol) was
(n d, 300 MHz, CDCl3): 1.94 (2H,
, cmꢁ1): 3359 vs (eOH). 1H NMR (
dissolved in 60 mL of dry THF. To this solution, LiAlH4 (0.34 g,
9.00 mmol) was added and the reaction mixture was stirred at
room temperature for 15 h. The reaction was quenched and
extracted with EtOAc (2 ꢂ 30 mL) using a separating funnel. The
organic layer was dried over Na2SO4, filtered and evaporated to get
a yellow powder which was recrystallised with dichloromethane/
hexane mixture to get reddish yellow crystals of the pure
compound 1. Yield: 2.10 g, 3.88 mmol, 97%. Mp: 170e172 ꢀC. Anal.
Found: C, 77.89; H, 5.32. Calcd. for C35H29O2Co: C, 77.77; H, 5.41. IR
brs, OH), 4.03e4.13 (4H, m, CH2) 4.52e4.54 (1H, t, 3J ¼ 2.7 Hz, CpH),
4.69 (2H, d, 3J ¼ 2.4 Hz CpH), 7.23e7.25 (12H, m, m/p-PhH),
(n d, 300 MHz, CDCl3): 0.93 (2H,
, cmꢁ1): 3359 vs (eOH). 1H NMR (
Fig. 5. ORTEP diagram of 6 with thermal ellipsoids at the 30% probability level. Phenyl
ꢀ
Fig. 4. ORTEP diagram of 5 with thermal ellipsoids at the 30% probability level. Phenyl
hydrogen atoms have been omitted for clarity. Selected bond lengths (A), Co(1)eC(1)
ꢀ
hydrogen atoms have been omitted for clarity. Selected bond lengths (A), C(10)eC(11)
2.066(4), Co(1)eC(6) 1.980(3), C(1)eC(2) 1.427(5), C(2)eC(3) 1.418(5), C(1)eC(10)
1.441(5), C(10)eC(11) 1.163(5), C(2)eC(12) 1.427(6), C(12)eC(13) 1.156(6). Selected bond
angles (ꢀ), C(1)eC(10)eC(11) 178.3(5), C(2)eC(12)eC(13) 177.5(5), C(2)eC(1)eC(10)
125.6(4), C(5)eC(1)eC(10) 126.0(4).
1.183(9), C(3)eC(12) 1.427(9), C(12)eC(13) 1.176(9). Selected bond angles (ꢀ), C(1)eC(10)e
C(11) 177.6(8), C(3)eC(12)eC(13) 179.1(7), C(2)eC(1)eC(10) 125.5(5), C(5)eC(1)eC(10)
126.9(6).

104
N. Singh et al. / Journal of Organometallic Chemistry 717 (2012) 99e107
7.41e7.45 (8H, m, o-PhH). 13C NMR (
d, 75 MHz, CDCl3): 57.93 (CH2),
74.98 (C4Ph4), 83.73, 84.04, 95.14 (CpC), 126.64, 128.21, 128.62,
135.73 (PhC). HRMS: Calcd. for C35H29O2CoNa: 563.1397, found:
563.1403.
4.5. Preparation of [h h
5-1,3-(CHO)2C5H3]Co( 4-C4Ph4) (3)
To a solution of compound 1 (0.65 g, 1.20 mmol) in 15 mL of
ꢀ
CH2Cl2, molecular sieves 4 A and N-methyl morpholine-N-oxide
(0.48 g, 4.08 mmol) were added. To this, tetrapropylammonium
perruthenate (0.04 g, 0.12 mmol) was added. The mixture was
found to darken and it was stirred at room temperature for 2 h. The
reaction mixture was then washed with saturated sodium sulphite
(20 mL), brine (20 mL) and saturated CuSO4 solution (20 mL). The
organic layer was dried (Na2SO4), filtered and the solvent was
evaporated off. The remaining residue was chromatographed on
neutral alumina using 4:1 hexane/ethylacetate as eluent. The only
yellow fraction was collected which on evaporation of solvent gave
a reddish orange powder which was characterized as 7. Yield:
0.59 g, 1.10 mmol, 92%. Mp: 185e187 ꢀC. Anal. Found: C, 78.47; H,
4.59. Calcd. for C35H25O2Co: C, 78.35; H, 4.70. IR (
(C]O). 1H NMR (
, 300 MHz, CDCl3): 5.43 (2H, s, CpH), 5.83 (1H, s,
CpH), 7.24e7.36 (12H, m, m/p-PhH), 7.43e7.45 (8H, m, o-PhH), 9.35
(2H, s, CHO). 13C NMR (
, 75 MHz, CDCl3): 79.33 (C4Ph4), 82.91,
87.47, 96.17 (CpC), 127.85, 128.43, 128.78, 133.51 (PhC), 190.30
(CHO). HRMS: Calcd. for C35H25O2CoNa: 559.1081, found: 559.1086.
n
, cmꢁ1): 1676 vs
d
d
Fig. 6. ORTEP diagram of 8 with thermal ellipsoids at the 30% probability level. Phenyl
hydrogen atoms have been omitted for clarity. Selected bond lengths (A), Co(1)eC(1)
2.067(4), Co(1)eC(4) 2.076(4), N(1)eN(2) 1.207(6), N(5)eN(6) 1.118(7), N(4)eC(11)
1.466(6), C(3)eC(4) 1.413(6), C(2)eC(11) 1.483(6). Selected bond angles (ꢀ), N(1)e
N(2)eN(3) 173.5(6), N(4)eN(5)eN(6) 171.8(6), N(2)eN(1)eC(10) 119.0(4), N(5)eN(4)e
C(11) 116.1(4), N(1)eC(10)eC(1) 109.3(4), N(4)eC(11)eC(2) 114.3(4).
ꢀ
4.6. Preparation of [h h
5-1,2-(CHO)2C5H3]Co( 4-C4Ph4) (4)
Compound 2 (0.65 g, 1.20 mmol) was taken in place of 1 in an
identical reaction by which 3 was synthesized to prepare 4. Yield:
0.59 g, 1.10 mmol, 91%. Mp: 220e222 ꢀC. Found: C, 78.22; H, 4.76.
Calcd. for C35H25O2Co: C, 78.35; H, 4.70. IR (
1H NMR (
, 300 MHz, CDCl3): 5.05 (1H, s, CpH), 5.50 (2H, s, CpH),
7.24e7.35 (12H, m, m/p-PhH), 7.40e7.43 (8H, m, o-PhH), 9.79 (2H, s,
CHO). 13C NMR (
, 75 MHz, CDCl3): 79.61 (C4Ph4), 89.42, 91.22, 92.04
n
, cmꢁ1): 1674 vs (C]O).
d
d
(CpC), 127.84, 128.38, 128.70, 133.49 (PhC), 191.18 (CHO). HRMS:
Calcd. for C35H25O2CoNa: 559.1081, found: 559.1084.
4.7. Preparation of [h h
5-1,3-(CH^C)2C5H3]Co( 4-C4Ph4) (5)
n-BuLi (2.40 mL, 1.6 M in hexanes, 3.84 mmol) was added to
solution of (chloromethyl) triphenylphosphonium chloride
a
(0.82 g, 3.80 mmol) in 30 mL of THF at ꢁ78 ꢀC. The solution was
warmed to room temperature while stirring and then re-cooled
to ꢁ78 ꢀC. To the deep red-orange solution of the resulting ylide
was added a solution of 3 (1.17 g, 2.05 mmol) in THF (20 mL) via
cannula over a period of 5 min. The resulting reaction mixture was
warmed to room temperature and stirred for 15 h. After evapora-
tion of the solvent, the residue was extracted with 10% aqueous
NH4Cl (50 mL) and Et2O (2 ꢂ 30 mL) The combined organic layers
were dried (Na2SO4), filtered and evaporated to get a dark orange
residue. This residue was washed with hexane, dried in vacuum
and dissolved in 35 mL of THF. The solution was cooled to ꢁ40 ꢀC
and n-BuLi (4.00 mL, 1.6 M, 6.40 mmol) was added while stirring,
The reaction mixture was found to darken slowly and after 15 min,
the solution was cooled further to ꢁ80 ꢀC. To the cooled solution,
20% H2SO4 (5 mL) was added upon which it turned yellow. The
reaction mixture was warmed to room temperature and was
extracted with diethyl ether (2 ꢂ 30 mL), washed with brine
(30 mL) and dried over Na2SO4. The dried ether extract was filtered
and the solvent was evaporated off to get a yellow residue which
was chromatographed on alumina using ethyl acetateehexane as
eluent. The first band was collected at 2% ethyl acetate/hexane
which upon evaporation of solvent gave a yellow crystalline
Fig. 7. ORTEP diagram of 10 with thermal ellipsoids at the 30% probability level. Phenyl
hydrogen atoms have been omitted for clarity. Selected bond lengths (A), O(1)eC(11)
1.303(9), O(2)eC(11) 1.170(10), O(4)eC(14) 1.196(7), C(1)eC(10) 1.488(10), C(1)eC(2)
1.437(8), C(2)eC(3) 1.393(8). Selected bond angles (ꢀ), O(1)eC(11)eO(2) 121.8(9),
O(2)eC(11)eC(12) 124.9(9), O(4)eC(14)eO(3) 124.9(7), O(1)eC(10)eC(1) 110.7(6),
C(2)eC(1)eC(10) 128.0(6).
ꢀ

N. Singh et al. / Journal of Organometallic Chemistry 717 (2012) 99e107
105
Table 1
X-ray crystal structure parameters of compounds 2e6, 8 and 10.
Parameters
2
3
4
5
6
8
10
Empirical formula
Formula weight
Crystal system
Space group
C35H29CoO2
540.51
Monoclinic
C2/c
21.195(5)
16.947(4)
15.867(4)
90
110.629(4)
90
5334.0(2)
8
C35H25CoO2
536.48
Triclinic
P
9.683(4)
14.309(6)
20.351(9)
101.771(8)
94.356(9)
104.851(8)
2643.5(2)
4
C35H25CoO2
536.48
Orthorhombic
Pbca
16.953(2)
15.521(2)
19.524(2)
90
C37H25Co
528.50
Monoclinic
P21/c
9.537(2)
15.933(3)
17.997(4)
90
93.846(5)
90
2728.6(10)
4
C37H25Co
528.50
Monoclinic
P21/c
10.423(3)
15.407(4)
17.166(5)
90
105.669(6)
90
2654.3(12)
4
C35H27CoN6
590.56
Monoclinic
P21/n
17.524(3)
12.633(2)
13.439(3)
90
103.753(4)
90
2889.9(9)
4
C39H32CoO4
624.58
Monoclinic
P21/n
13.297(2)
17.806(3)
13.394(2)
90
98.018(3)
90
3140.2(9)
4
ꢀ
a (A)
ꢀ
b (A)
ꢀ
c (A)
a
b
g
(deg)
(deg)
(deg)
90
90
3
ꢀ
V (A )
5137.6(10)
8
Z
T/K
298
0.71073
1.346
0.674
1.039
1.58e25.00
25274
4693
3730
0.051
298
0.71073
1.348
0.680
1.057
1.51e25.00
19171
9253
6760
0.046
150
0.71073
1.387
0.700
1.406
2.08e25.0
46756
4522
4429
0.068
298
0.71073
1.287
0.653
1.065
1.71e25.00
14140
4800
3092
0.076
298
0.71073
1.323
0.671
1.016
1.81e25.00
13824
4686
3123
0.069
298
0.71073
1.357
0.629
1.014
1.2e25.00
15651
3522
5077
0.050
298
0.71073
1.319
0.587
1.266
1.20e25.00
14806
5520
4631
0.048
ꢀ
l
(A)
rcalcd (g/cm3)
(mm-1)
Goodness of fit
range
m
q
Total reflections
Unique reflections
Ovserved data [I >
Rint
s
(I)]
R1a[F2 > 2
CCDC number
s
(F2)], wR2b(F2)
0.0440, 0.1243
880636
0.0647, 0.1469
880637
0.0864, 0.1646
880638
0.0712, 0.1898
880639
0.0575, 0.1377
880640
0.0539, 0.1792
880641
0.0919, 0.1974
880642
a
R1 ¼ SjFoj ꢁ jFcjj/SjFoj.
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ
P
P
ꢀ
ꢀ
ꢀ
wR2 ¼ f ½wð F2 ꢁ Fc2 Þ2ꢃ=
wðF2Þ2 g1=2
.
b
ꢀ
ꢀ
ꢀ
o
o
powder characterized as 5. Yield: 0.49 g, 0.93 mmol, 45%. Mp:
181e183 ꢀC. Anal. Found: C, 84.23; H, 4.71. Calcd. for C37H25Co: C,
(CH2), 75.84 (C4Ph4), 82.22, 83.85, 92.35 (CpC), 126.85, 128.25,
128.58, 135.27 (PhC). HRMS: Calcd. for C35H27CoN6Na 613.1527,
found 613.1538.
84.08; H, 4.77. IR (n d, 300 MHz,
, cmꢁ1): 2109 m (C^CH). 1H NMR (
CDCl3): 2.44 (1H, s, C^CH), 4.76 (2H, s, CpH), 4.93 (1H, s, CpH),
7.24e7.26 (12H, m, m/p-PhH), 7.46e7.49 (8H, m, o-PhH). 13C NMR
(d, 75 MHz, CDCl3): 77.19 (C4Ph4), 76.73 (C^CH), 78.73(C^CH),
4.10. Preparation of [h h
5-1,2-(CH2N3)2C5H3]Co( 4-C4Ph4) (8)
87.28, 88.67 (CpC), 126.66, 127.95, 128.6, 134.46 (PhC). HRMS: Calcd.
for C37H25CoNa: 551.5186, found: 551.5186.
Compound 2 (0.27 g, 0.50 mmol) was used instead of 1 in an
identical reaction by which 7 was synthesized. The reaction yielded
8 Yield: 0.28 g, 0.47 mmol, 94%. Mp: 158e161 ꢀC. Found: C, 71.36; H,
4.8. Preparation of [h h
5-1,2-(CH^C)2C5H3]Co( 4-C4Ph4) (6)
4.50; N,14.37. Calcd. for C35H27N6Co: C, 71.18; H, 4.61; N,14.23. IR (n,
cmꢁ1): 2102 vs (N3). 1H NMR (
d, 300 MHz, CDCl3): 3.55e3.60 (2H, d,
Compound 4 (1.17 g, 2.05 mmol) was taken in place of 3 in an
identical reaction by which was synthesized to prepare
compound 6. Yield: 0.45 g, 0.86 mmol, 42%. Mp: 172e174 ꢀC. Anal.
Found: C, 84.30; H, 4.83. Calcd. for C37H25Co: C, 84.08; H, 4.77. IR (
2J ¼ 13.5 Hz CH2), 3.66e3.70 (2H, d, 2J ¼ 13.5 Hz, CH2), 4.65e4.67
(1H, t, 3J ¼ 2.7 Hz, CpH), 4.75e4.76 (2H, d, 3J ¼ 2.7 Hz, CpH),
7.23e7.25 (12H, m, m/p-PhH), 7.40e7.42 (8H, m, o-PhH). 13C NMR
5
n
,
(d, 75 MHz, CDCl3): 46.67 (CH2), 75.65(C4Ph4), 84.41, 89.71 (CpC),
126.90, 128.34, 128.65, 135.23 (PhC). HRMS: Calcd. for
C35H27CoN6Na 613.1527, found 613.1560.
cmꢁ1): 2113 m (C^CH). 1H NMR (
d, 300 MHz, CDCl3): 2.64 (2H, s,
C^CH), 4.56e4.58 (1H, t, 3J ¼ 2.7 Hz, CpH), 4.78e5.79 (2H, d,
3J ¼ 2.7 Hz, CpH), 7.15e7.26 (12H, m, m/p-PhH), 7.40e7.55 (8H, m, o-
PhH). 13C NMR (
d, 75 MHz, CDCl3): 77.20 (C4Ph4), 78.54 (C^CH),
4.11. Preparation of [h h
5-1,3-(CH2OAc)2C5H3]Co( 4-C4Ph4) (9)
80.78(C^CH), 85.24, 87.06 (CpC), 126.70, 127.99, 128.89, 134.56
(PhC). HRMS: Calcd. for C37H25CoH: 529.1366, found 529.1362.
Compound 1 (0.15 g, 0.27 mmol) was dissolved in 3 mL of
glacial acetic acid and stirred at 80 ꢀC for 1 h. The reaction mixture
was neutralized with aq. NaHCO3 and extracted with CH2Cl2
(3 ꢂ 25 mL). The combined organic layer was dried over Na2SO4
and after evaporating the solvent, the residue was purified by
column chromatography on silica gel using 10% ethyl acetate/
hexane as eluent. Evaporation of the solvent gave yellow crystal-
line solid characterized as 9 (Yield: 0.16 g, 0.26 mmol, 95%). Mp:
150e152 ꢀC. Anal. Found: C, 74.95; H, 5.32; Calcd. for C39H33CoO4:
4.9. Preparation of [h h
5-1,3-(CH2N3)2C5H3]Co( 4-C4Ph4) (7)
Compound 1 (0.27 g, 0.50 mmol) was dissolved in 5 mL of glacial
acetic acid. Sodium azide (0.26 g, 4.00 mmol) was added to the
solution and stirred at 70 ꢀC for 15 h. The reaction mixture was
neutralized with aq. NaHCO3, extracted with CH2Cl2 (3 ꢂ 25 mL)
and combined organic layer was dried over Na2SO4. After evapo-
rating the solvent, the residue was purified by column chroma-
tography on silica gel using 10% ethyl acetate/hexane as eluent.
Evaporation of the solvent gave yellow crystalline solid character-
ized as 7 Yield: 0.28 g, 0.48 mmol, 95%. Mp: 150e152 ꢀC. Found: C,
71.39; H, 4.56; N, 14.40. Calcd. for C35H27N6Co: C, 71.18; H, 4.61; N,
C, 74.99; H, 5.33; IR (n d, 300 MHz,
, cmꢁ1): 1739 vs (C]O). 1H NMR (
CDCl3): 1.96(6H, s, CH3), 4.37e4.41 (2H, d, 2J ¼ 12.0 Hz CH2),
4.50e4.54 (2H, d, 2J ¼ 12.0 Hz, CH2), 4.81 (2H, s, CpH), 4.96 (1H, s,
CpH), 7.07e7.34 (12H, m, m/p-PhH), 7.53e7.55 (8H, m, o-PhH). 13C
14.23. IR (
n
, cmꢁ1): 2095 vs (N3). 1H NMR (
d
, 300 MHz, CDCl3):
NMR (d, 75 MHz, CDCl3): 20.75 (CH3), 60.73 (CH2), 75.59 (C4Ph4),
3.44e3.48 (2H, d, 2J ¼ 13.5 Hz CHH), 3.64e3.70 (2H, d, 2J ¼ 13.5 Hz,
CHH), 4.70 (2H, s, CpH), 4.79 (1H, s, CpH), 7.23e7.26 (12H, m, m/p-
82.22, 83.95, 92.39 (CpC), 126.67, 128.13, 128.58, 135.43 (PhC),
170.52 (C]O). HRMS: Calcd. for C35H27CoO4Na 647.1608, found
647.1614.
PhH), 7.40e7.42 (8H, m, o-PhH). 13C NMR (
d, 75 MHz, CDCl3): 48.40

106
N. Singh et al. / Journal of Organometallic Chemistry 717 (2012) 99e107
4.12. Preparation of [
h
5-1,2-(CH2OAc)2C5H3]Co(
h
4-C4Ph4) (10)
85.51 (CpC), 122.18, 126.14, 127.73, 128.39, 128.63, 128.87, 135.01
(PhC), 135.16 (C]CH), 142.20 (C]CH). HRMS: Calcd. for
Compound 2 (0.15 g, 0.27 mmol) was used instead of 1 in an
identical reaction by which 9 was synthesized. The reaction yiel-
ded 10 Yield: 0.16 g, 0.26 mmol, 96%. Mp: 158e161 ꢀC. Found: C,
C
51H39CoN6Na: 817.2466, found: 817.2458.
4.16. Preparation of [ h
h
5-1,3-(CH2NH2)2C5H3]Co( 4-C4Ph4) (14)
74.93; H, 5.30; Calcd. for C39H33CoO4: C, 74.99; H, 5.33. IR (
n,
cmꢁ1): 1740 vs (C]O). 1H NMR (
d, 300 MHz, CDCl3): 1.88 (6H, s,
To the solution of 7 (0.30 g, 0.51 mmol) in 30 mL of THF, LiAlH4
(0.06 g, 1.58 mmol) was added and the reaction mixture was
refluxed for 3 h. The reaction was quenched and extracted with
EtOAc (2 ꢂ 30 mL). The organic layer was dried over Na2SO4, filtered
and solvent was evaporated to get a yellow powder which was
recrystallised to get pure fine crystals of 14 Yield: 0.25 g, 0.46 mmol,
91%. Mp: 150e152 ꢀC. Anal. Found: C, 77.97; H, 5.77; N, 5.26. Calcd.
CH3), 4.45e4.50 (4H, m, CH2), 4.62 (1H, s, CpH), 4.77e4.78 (2H, s,
CpH), 7.23e7.25 (12H, m, m/p-PhH), 7.40e7.42 (8H, m, o-PhH). 13C
NMR (d, 75 MHz, CDCl3): 20.80 (CH3), 59.18 (CH2), 75.50 (C4Ph4),
84.71, 85.02, 90.32 (CpC), 126.75, 128.21, 128.67, 135.42 (PhC),
170.53 (C]O). HRMS: Calcd. for C39H33CoO4Na 647.1608, found
647.1616.
for C35H31N2Co: C, 78.05; H, 5.80; N, 5.20. IR (n
, cmꢁ1): 2095 vs (N3).
4.13. Preparation of [h h
5-1,3-(CH2SPh)2C5H3]Co( 4-C4Ph4) (11)
1H NMR (
d
, 300 MHz, CDCl3): 3.11e3.15 (2H, d, 2J ¼ 14.4 Hz CH2),
3.18e3.23 (2H, d, 2J ¼ 14.4 Hz, CH2), 4.58 (2H, s, CpH), 4.70 (1H, s,
CpH), 7.15e7.30 (12H, m, m/p-PhH), 7.44e7.45 (8H, m, o-PhH). 13C
To the solution of 1 (0.27 g, 0.50 mmol) in 5 mL of dry
dichloromethane was added phenyl mercaptan (0.06 g, 0.50 mmol).
Trifluoroacetic acid (0.12 g, 1.05 mmol) was added drop wise to the
solution and stirred for 2 min. The solvent was evaporated and
residue was chromatographed on an alumina column using 1:3
ethylacetateehexane mixture as eluent. The yellow fraction on
evaporation of solvent gave 11 Yield: 0.34 g, 0.46 mmol, 92%. Mp:
200e204 ꢀC (decom). Anal. Found: C, 77.69; H, 5.19. Calcd. for
NMR (d, 75 MHz, CDCl3): 39.16 (CH2), 74.60 (C4Ph4), 79.07, 81.12,
100.47 (CpC), 126.40, 128.18, 128.56, 136.25(PhC). HRMS: Calcd. for
C35H31CoN2 538.1819, found 538.1823.
4.17. Preparation of h h
5-1,3-[(PhN]CH)2C5H3]Co( 4-C4Ph4) (15)
To the solution of 3 (0.28 g, 0.50 mmol) in 10 mL of toluene,
C47H37S2Co: C, 77.88; H, 5.14. IR (n
, cmꢁ1): 1566 vs (CH2SPh) 1H
ꢀ
molecular sieves 4 A and aniline (0.50 mL) were added and the
NMR (
d
, 300 MHz, CDCl3): 3.10e3.15 (2H, d, 2J ¼ 13.3 Hz CH2),
reaction mixture was refluxed for 1 h. After cooling, the solvent
was evaporated and the residue was purified by column chroma-
tography on silica gel using 15% ethyl acetate/hexane as eluent.
Evaporation of the solvent gave red crystalline solid characterized
as 15 Yield: 0.34 g, 0.49 mmol, 98%. Mp: 161e163 ꢀC. Anal. Found:
C, 82.26; H, 5.18; N, 4.12. Calcd. for C47H35CoN2: C, 82.20; H, 5.14; N,
3.26e3.30 (2H, d, 2J ¼ 13.3 Hz, CH2), 4.4e4.44 (2H, s, CpH), 4.51 (1H,
s, CpH), 7.04e7.07 (4H, m, o-SPhH), 7.13e7.23 (18H, m, m/p-PhH, m/
p-SPhH), 7.38e7.41 (8H, m, o-PhH). 13C NMR (
d, 75 MHz, CDCl3):
31.75 (CH2), 75.20 (C4Ph4), 83.06, 83.47, 94.04 (CpC), 126.12, 126.40,
128.15, 128.60, 128.69, 129.81 (PhC), 135.75 (ipso-Ph), 136.30 (ipso-
SPh) HRMS: Calcd. for C47H37S2Co 724.1669, found 724.1695.
4.08. IR (n d, 300 MHz,
, cmꢁ1): 1620, 1589 vs (C]N). 1H NMR (
CDCl3): 5.39 (2H, s, CpH), 5.79 (1H, s, CpH), 6.60e6.71 (4H, m,
PhH), 7.08e7.29 (18H, m, PhH), 7.44e7.47 (8H, m, PhH), 7.75 (2H, s,
4.14. Preparation of [h h
5-1,2-(CH2SPh)2C5H3]Co( 4-C4Ph4) (12)
CH]N). 13C NMR (
d, 75 MHz, CDCl3): 77.74 (C4Ph4), 81.59, 86.11,
Compound 2 (0.27 g, 0.50 mmol) was used instead of 1 in an
identical reaction to synthesize 12 Yield: 0.34 g, 0.47 mmol, 94%.
Mp: 155e157 ꢀC. Anal. Found: C, 77.96; H, 5.05. Calcd. for
95.52 (CpC), 120.78, 125.51, 127.00, 128.16, 128.79, 128.83,
134.67(PhC) 151.86 (ipsoph), 157.10 (C]N). HRMS: Calcd. for
C47H35CoN2Na 709.2030, found 709.2034.
C47H37S2Co: C, 77.88; H, 5.14. IR (n
, cmꢁ1): 1564 vs (CH2SPh). 1H
NMR (
d
, 300 MHz, CDCl3): 3.27e3.32 (2H, d, 2J ¼ 13.5 Hz CH2),
Acknowledgements
3.33e3.37 (2H, d, 2J ¼ 13.5 Hz, CH2), 4.43e4.44 (1H, t, 3J ¼ 2.7 Hz,
CpH), 4.49e4.50 (2H, d, 3J ¼ 2.7 Hz, CpH), 7.10e7.28 (22H, m, m/p-
We thank the Department of Science and Technology (DST) of
India for financial assistance in the form of research grant to A.J.E.
(No. SR/SI/IC-43/2010). N.S. thanks the UGC India for JRF and SRF.
We thank DST-FIST and IITD for funding of the single-crystal X-ray
diffraction and HRMS facilities at IIT Delhi.
PhH, -SPhH), 7.39e7.42 (8H, m, o-PhH). 13C NMR (
d, 75 MHz, CDCl3):
29.70 (CH2), 74.93 (C4Ph4), 83.05, 83.83, 91.85 (CpC), 126.03,126.35,
127.47, 128.12, 128.67, 129.63, (PhC), 135.62 (ipso-Ph), 136.61 (ipso-
SPh) HRMS: Calcd. for C47H37S2Co 724.1669, found 724.1682.
4.15.
h h
5-{1,2-[PhCH2(C2HN3)]2C5H3}Co( 4-C4Ph4) (13)
Appendix A. Supplementary material
1,2-dialkyne 6 (0.26 g, 0.50 mmol) was dissolved in 10 mL
tBuOH; benzyl azide (0.13 g, 1.00 mmol) was added to this solution
and stirred for 5 min. CuSO4.5H2O (0.02 g, 0.10 mmol in 7 mL water)
followed by sodium ascorbate (0.04 g, 0.2 mmol in 3 mL water) was
added and the reaction mixture was stirred for 15 h at room
temperature. CH2Cl2 (50 mL) was added to the reaction mixture,
washed with brine (15 mL) and the organic layer was dried over
sodium sulfate. After evaporating the solvent, the residue was
purified by column chromatography on silica gel using 20% ethyl
acetate/hexane as eluent. Evaporation of the solvent gave yellow
crystalline solid characterized as 13 (Yield: 0.31 g, 0.39 mmol, 78%).
Mp: 174e176 ꢀC. Found: C, 77.16; H, 4.90; N, 10.48. Calcd. for
Crystallographic data for the structural analysis has been
deposited with the Cambridge Crystallographic Data Centre, CCDC
Nos. 880636 to 880642 for compounds 2e6, 8 and 10 respectively.
Copies of this information may be obtained free of charge from: The
Director, CCDC, 12 Union Road, Cambridge, CB2 1EZ UK (fax (int
code): þ44 1223 336 033 or e-mail: deposit@ccdc.cam.ac.uk or
www: http://www.ccdc.cam.ac.uk).
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