Supplementary Material for Dalton Transactions
This journal is © The Royal Society of Chemistry 2004
Paper Title:
A heterodifunctionalised ferrocene derivative that self-assembles through complementary
hydrogen-bonding interactions
Authors:
Hidekazu Miyaji, Miroslav Dudic, Gilles Gasser, Stephen J. Green,* Nina Moran, Ivan Prokes,
Gaël Labat, Helen Stoeckli-Evans, Sharon M. Strawbridge and James H. R. Tucker.*
Graphical Abstract
N
O
O
H
N
H
O
O
2
N
H
Fe
O
N
N
Fe
O
H
H
O
N
O
Fe
OH
A 1,1’-heterodifunctionalised ferrocene derivative self-assembles in organic solvents through
complementary H-bonding interactions, as evidenced by 1H NMR spectroscopy and vapour
pressure osmometry studies.
Electronic Supplementary Information
Synthesis of compound 2:
1,1’-ferrocenedicarboxylic acid, (2g, 7.30 mmol) was added to anhydrous dichloromethane (80
ml) and to this solution oxalyl chloride (12.7 ml, 0.146 mol) was added dropwise and the
mixture left to stir overnight at room temperature. The solution was refluxed until all of the
solid had dissolved (~2.5 hours) and then the solvent was removed under reduced pressure. The
obtained crude dichlorocarbonylferrocene, was dried under vacuum and then dissolved in
anhydrous THF (30 ml) and added to a solution of 2-amino-6-picoline (0.789 g, 7.30 mmol) and
triethylamine (5.1 ml, 36.5 mmol) in anhydrous THF (30 ml). The reaction mixture was stirred
at room temperature over night. THF was removed on a rotary evaporator and the residue
dissolved in chloroform (200 ml) and washed with water (100 ml). The aqueous layer was
extracted with chloroform and the combined organic layers were then dried over magnesium
sulphate. The mixture was filtered and the solvent evaporated. The product was purified by
column chromatography on silica gel (CHCl3:EtOAc=1:20) to yield 1-chlorocarbonyl-1’-[{(6methyl-2-pyridyl)amino}carbonyl]ferrocene (compound 3), as a burnt orange solid (0.87 g, 2.25
mmol, 31%). 1H NMR (400 MHz, CDCl3) (ppm): 2.35 (s, 3H, pyCH3), 4.62 (dd, J=2.0Hz,
1.9Hz, 2H, FcH), 4.63 (dd, J=2.0Hz, 1.9Hz, 2H, FcH), 4.92 (dd, J=2.0Hz, 1.9Hz, 2H, FcH),
5.07 (dd, J=2.0Hz, 1.9Hz, 2H, FcH), 6.85 (d, J=7.6Hz, 1H, pyH), 7.57 (dd, J=8.0Hz, 7.6Hz,
1H, pyH), 8.10 (d, J=8.0Hz, 1H, pyH), 8.77 (s, 1H, amide NH). MS (CI+) m/e 347 (M-Cl)+. 1[{(6-methyl-2-pyridyl)amino}carbonyl]ferrocene-1’-carboxylic acid (compound 2) was also
obtained from same column in a subsequent band as a light orange solid (0.64 g, 1.76 mmol, 24
%) using CHCl3:MeOH as an eluent. 1H NMR (ca. 5 mM, 400 MHz, CDCl3) (ppm): 1.99 (s,
3H, pyCH3), 4.53 (dd, J=2.0Hz, 1.9Hz, 2H, FcH), 4.59 (dd, J=2.0Hz, 1.9Hz, 2H, FcH), 4.93
(dd, J=2.0Hz, 1.9Hz, 2H, FcH), 5.33 (dd, J=2.0Hz, 1.9Hz, 2H, FcH), 6.77 (d, J=7.3Hz, 1H,
pyH), 7.66 (dd, J=8.4Hz, 7.3Hz, 1H, pyH), 8.49 (d, J=8.4Hz, 1H, pyH), 10.65 (s, 1H, amide
NH). 13C NMR(100 MHz, CDCl3) (ppm):21.68, 71.35, 72.35, 72.64, 73.13, 112.32, 119.05,
Supplementary Material for Dalton Transactions
This journal is © The Royal Society of Chemistry 2004
139.91 151.91, 155.72, 169.21, 175.59. MS (CI+) m/e 364 (M+). HRMS(CI+): C18H16O3N2Fe
calc. 364.0510, found 364.0513 = 0.7 ppm. Anal. Calcd. for C18H16O3N2Fe.0.5H2O (373.19):
C, 57.93; H, 4.59; N. 7.51. Found: C, 57.80; H, 4.48; N, 7.64.
Electrochemistry:
Conditions for cyclic voltammetry: reference electrode, Ag/AgCl; counter electrode, Pt wire;
working electrode, glassy carbon; scan rate, 100 mV/s–1, supporting electrolyte, TBAP (0.1
mM). CH2Cl2 was used as a solvent instead of CHCl3 due to the poor electrochemical
reversibility of both 2 and ferrocene in CHCl3. 1H NMR studies on compound 2 in CD2Cl2 (ca.
5 mM) revealed similar aggregation behaviour to that observed in CDCl3.
Vapour pressure osmometry:
A Vapro 5520 vapor pressure osmometer (manufacturer: Wescor) was used for molecular
weight determination. So that organic solvents could be used, the instrument response at 298 K
was calibrated for ferrocene at known concentrations (M). The calibration graph is shown
below.
VPO Calibration with Ferrocene in Chloroform
60
50
y = 5315.8x + 0.3477
R2 = 0.9808
Reading
40
30
20
10
0
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0.009
0.01
[Ferrocene] / M
Compound 4:
0.0161 g (MW = 320.175 g/mol) was dissolved in 10 mL of dry chloroform ([4] = 5.03 mM).
An instrument reading of 26.25(±1.5) was measured, giving an observed concentration of
4.87(±0.3) mM, corresponding to an average molecular mass of 330±40 g/mol.
Compound 2:
0.0210 g (MW = 364.184 g/mol) was dissolved in 10 mL of dry chloroform ([2]mon = 5.77 mM).
An instrument reading of 16.5(±2.5) was measured, giving an observed concentration of
3.04(±0.48) mM, corresponding to an average molecular mass of 708±112 g/mol. Given the
high  value for the NH proton at 5 mM (1H NMR spectroscopy), which is indicative of all
Supplementary Material for Dalton Transactions
This journal is © The Royal Society of Chemistry 2004
available NH protons being strongly H-bonded, a scenario in which equal amounts of a
monomer and a trimer are present in solution at concentrations approaching that of the dimer, is
unlikely.
Determination of the dimerisation constant of 2:
The dimerisation constant (KD) of 2 in 1% DMSO-d6/CDCl3 was determined by 1H NMR
spectroscopy using a dilution technique. The data were analyzed by a linear graphical method
for dimerisation developed by Spurr and Byers.7a The experiment started with the most
concentrated solution (St = 10 mM) of compound 2, which was then diluted gradually until the
detection limit was reached. The 1H NMR spectrum (obs.= the chemical shift of the amide
proton of 2) was recorded for each of these concentrations. The chemical shift of this proton in
a very dilute solution (ca
monomer. The
dimerisation constant (KD) of 2 was then calculated as shown below:
= 22KDSt/(1+4KDSt) (Spurr and Byers equation).
where= obs.-monomer, = dimer-monomer, St = total concentration.
1/ = (1/St)(1/ 22KD) + 2/(linear form).
Slope = 1/ 22KD, Intercept = 2/
Intercept/Slope = 4KD
4KD= 0.539/0.00181
KD = 74.4 M-1