Development of a new methodology for the synthesis of chloro(glycinato)1,10-phenanthroline copper(II) monohydrate and analogous complexes and study of their catalytic utility towards selective hydroxylation of phenol

Article abstract of DOI:10.1080/24701556.2017.1357607

A new simple and convenient method has been developed for the synthesis of copper(II)complexes using Proline and Glycine as ligand. The complexes were characterized by using conventional spectroscopic techniques and by determining structure. Methodology developed gives substantial yield of the products. Chloro(Glycinato) 1,10-Phenanthroline Copper(II) monohydrate and other complexes effectively catalyze the selective orthohydroxylation of phenol, in presence of Hydrogen peroxide, in water. Catechol formation was confirmed by IR and NMR spectroscopy. Hydroxylation reaction produces moderate to good yield of the product catechol. Longer time duration results in decrease of yield.

Full text of DOI:10.1080/24701556.2017.1357607

Inorganic and Nano-Metal Chemistry
ISSN: 2470-1556 (Print) 2470-1564 (Online) Journal homepage: http://www.tandfonline.com/loi/lsrt21
Development of a new methodology for the
synthesis of chloro(glycinato)1,10-phenanthroline
copper(II) monohydrate and analogous complexes
and study of their catalytic utility towards
selective hydroxylation of phenol
S. Baruah & A. Puzari
To cite this article: S. Baruah & A. Puzari (2017): Development of a new methodology for
the synthesis of chloro(glycinato)1,10-phenanthroline copper(II) monohydrate and analogous
complexes and study of their catalytic utility towards selective hydroxylation of phenol, Inorganic
and Nano-Metal Chemistry, DOI: 10.1080/24701556.2017.1357607
To link to this article: http://dx.doi.org/10.1080/24701556.2017.1357607
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Jul 2017.
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Development of a new methodology for the synthesis of chloro(glycinato)1,10-phenanthroline
copper(II) monohydrate and analogous complexes and study of their catalytic utility towards
selective hydroxylation of phenol
S.Baruah and A. Puzari1,*
1Department of Chemistry, National Institute of Technology Nagaland, Chumukedima, Dimapur,
Pin-797 103, India
*Corresponding author email: amrit09us@yahoo.com
Abstract
A new simple and convenient method has been developed for the synthesis of
copper(II)complexes using Proline and Glycine as ligand. The complexes were characterized by
using conventional spectroscopic techniques and by determining structure. Methodology
developed gives substantial yield of the products. Chloro(Glycinato) 1,10-Phenanthroline
Copper(II) monohydrate and other complexes effectively catalyze the selective
orthohydroxylation of phenol , in presence of Hydrogen peroxide, in water. Catechol formation
was confirmed by IR and NMR spectroscopy. Hydroxylation reaction produces moderate to
good yield of the product catechol. Longer time duration results in decrease of yield.
Keyword:
1,10-Phenanthroline,Glycine, Methodology, Hydroxylation, Phenol, Catechol, Regioselectivity.
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1. Introduction
Copper(II) ions and its metal complexes have continued to attract attention of synthetic
chemists due to its various interesting structural features, its usefulness as models of the active
centers of various metallo-enzymes, magnetic, electronic, catalytic and biological properties.1
Copper(II) can effectively coordinate with N-donor atom of 1,10-phenanthroline and N,O-
donor atoms of many amino acids through chelation. Copper (II) formed a number of mixed
ligand metal complexes, where two or more ligand coordinates with the metal center. Many
mixed-ligand copper complexes containing 1,10-phenanthroline2 or 2,2’-bipyridine3 and other
ligands such as Schiff bases derived from amino acid4 have been reported. Herein we have
reported the synthesis, characterization and catalytic activity of Chloro(glycinato) 1,10-
phenanthroline copper(II) monohydrate and other few analogous complexes. Utility of such
complexes towards hydroxylation reaction of phenol has also been studied.
Use of Copper(II) complexes for selective hydroxylation of aromatic compounds is
industrially recognized as most challenging chemical reactions in synthetic organic chemistry.
Selective hydroxylation of phenols has lots of industrial significance because phenol and
catechol is widely used in industry as an important intermediate in manufacturing pesticides5 and
medicines6 and can also be used to produce perfumes (e.g., piperonal)7, dyes8, photosensitive
materials9, insecticides10 and many more. Catechol is used in the manufacture of the artificial
flavors vanillin and ethyl vanillin.11 Catechol also has wide applicability in pharmaceutical
industry. The pharmaceuticals used in the treatment of Parkinson’s disease and hypertension, L-
dopa and methyl L-dopa, are manufactured from catechol.12 Catechol is synthesized industrially
from phenol with hydrogen peroxide.13 The most common oxidizing agents used in phenol
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hydroxylation are hydrogen peroxide, and alkyl hydroperoxides. For hydroxylation reactions,
hydrogen peroxide is preferred over Organic peroxides because organic hydroperoxides are not
eco friendly and at the same time they are explosive, corrosive and flamable too.14 Hydrogen
peroxide is usually not selective because of the further oxidation of the phenol ring due to the
introduction of the activating -OH group which eventually causes formation of a mixture of acids
and polymeric compounds.15The reaction yields hydroquinone and catechol. During catechol
synthesis through hydroxylation, in most of the cases low selectivity towards catechol is a
general problem. The industrial catalysts give selectivity on catechol from 50 to 70%.16 Catechol
synthesis using hydrogen peroxide often accompanies with the formation of hydroquinone and o-
quinone as byproducts and product yield is also less.17
Metal complexes are usually employed as catalyst for hydroxylation reaction and in such
catalytic transformations structure of the ligands play a significant role. One of the most
prominent method is silanol-directed, Pd-catalyzed C–H oxygenation of phenols into
catechols.18 This method is highly site selective and general, as it allows for oxygenation of not
only electron-neutral but also electron-poor phenols. Copper(II) complexes are known to
catalyze efficiently the hydroxylation reactions of phenol and numerous research publications
are available. Copper alginate (dry beads and powder) catalysts showed highest conversions of
phenol as 52.9% and 62.5% over dry beads and powder, respectively, with a catechol-to-
hydroquinone ratio of 3:2.19 Copper substituted mesoporous silica (Cu-SBA-15) also shows
excellent catalytic activity towards hydroxylation of phenol using hydrogen peroxide with 62.4%
selectivity for catechol (about 71% selectivity).20The catalytic reaction of cis-bisglycinato copper
(II) monohydrate also catalyze hydroxylation of phenols in presence of hydrogen peroxide which
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yields catechol and hydroquinone (in 1:1.2 ratio) in good yield.21 Use of transition metal
complexes as catalyst generally associated with side reactions, especially when the time lag is
more.16 In all reviewed literature, two types of byproduct, quinone and macromolecular tars,
were formed due to over oxidation. The over oxidation problem is solved, in industry, by using
high phenol/hydrogen peroxide ratios along with high concentrations of phenol.16 It is expected
that catechol should be formed at a higher rate in short time duration and that will help to avoid
over oxidation because in that case high conversion of hydrogen peroxide will not be achieved.
Development of efficient catalytic system for such selective conversion of phenol is an
important research objective.
2. Experimental
2.1. Materials
Copper (II) sulphatepentahydrate, 1,10 – Phenanthroline, Glycine, Phenol, Hydrogen
peroxide, Hydrochloric acid, sulphuric acid, Diethyl ether were procured from TCI, Japan and
Sisco Research Laboratory and were used as received. Solvents are used after drying by standard
procedure.
2.2. Instrumental
IR spectra of the products were recorded on a Perkin Elmer Spectrum-BX IR spectrometer.
Cyclic Voltametry was recorded on a PAR 237A Potentiostate. Scan rate 20mV/S, electrolyte
used 0.1M KCl solution. Elemental analysis were carried out on a Thermo finnigan, FLASH EA
1112 Elemental analyser. NMR spectra were recorded on a Varian make 400 NMR Spectrometer
(Model: Mercury Plus).
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2.1. Synthesis of Chloro(glycinato)(1,10 – Phenanthroline) Copper(II) monohydrate
CuSO4.5H2O (0.249g, 0.001mol) was dissolved in 5.0 ml of 1N HCl. Glycine (0.750g,
0.001mol) and Phenanthroline (0.198g, 0.001mol) were dissolved separately in another 5.0ml of
1N HCl solution. The two solutions were then mixed properly in a 50.0ml round bottom flask to
obtain a blue coloured solution. The resulting solution was then stirred continuously for 1 hour at
700C which results in the formation of a green coloured precipitate. The precipitate obtained was
then filtered and washed with cold water (2 x 5.0ml) and then dried in the oven at 600Cfor 40
minutes to obtain a green coloured complex. Yield = 0.2563g, 69.0%, Anal. Calc.
C14N3O2H11Cl.H2OCu (mol. Wt. 371): C, 45.28; H, 3.51; N, 11.32. Found C, 45.78; H, 2.89; N,
9.042. It is to be noted that for heterocyclic compounds containing nitrogen in the cycle or in the
groups like azide, nitrile, nitro, etc. usually underestimated results are obtained for nitrogen due
to incomplete conversion of different forms of nitrogen to elemental nitrogen. IR spectra of the
complex 3368 cm-1
υ (NH), 3077 cm-1 υ (C-H, aromatic), 1635 cm-1 υ (c=o), 1582 cm-1
υ
(C=N), 1553 cm-1, 1513 cm-1, 1420 cm-1 υ (C-C str), 1351 cm-1, 1145 cm-1, 1108 cm-1, 853 cm-1,
720 cm-1, 610 cm-1 υ (M-N), 407 cm-1 υ (M-O).
2.2. Synthesis of Chloro (1,10 – Phenanthroline)(L-Prolinato) Copper(II) trihydrate
In an analogous manner CuSO4.5H2O (0.249g, 0.001mol) was dissolved in 5.0ml of
1NHCl. L-Proline (0.115g, 0.001mol) and Phenanthroline (0.198g, 0.001mol) were dissolved
separately in another 5.0ml of 1N HCl and both the solutions were mixed in a 50.0ml round
bottom flask to obtain a blue coloured solution. The resulting solution was then stirred
continuously for 1 hour at 700C. With progress of time the colour of the solution changes and a
green colour precipitate is formed. The precipitate obtained was then filtered and washed with
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cold water (2 x 5.0ml) and then dried in the oven for 40 minutes to obtain a green coloured
complex. Yield, 0.2436g, 62.0%, Anal. Calc. C17N3O2H16Cl.3H2OCu (Mol. Wt. 447): C, 45.63;
H, 3.57; N, 9.39. Found C, 45.59; H, 2.99; N, 8.71.For similar reasoning stated above, here also
we have obtained underestimated results for percentage of nitrogen. IR spectra of the complex
3353 cm-1 υ (NH), 3053 cm-1 υ (C-H, aromatic), 1626 cm-1 υ (c=o), 1587 cm-1 υ (C=N), 1553
cm-1, 1517 cm-1, 1424 cm-1 υ (C-C str), 1354 cm-1 , 1226 cm-1, 1104 cm-1, 1047 cm-1, 852 cm-1,
720 cm-1, 639 cm-1 υ (M-N), 408 cm-1 υ (M-O).
2.3. Synthesis of (glycinato)(1,10 – Phenanthroline)(Sulfonato) Copper(II) Monohydrate
A solution (5.0ml) of CuSO4.5H2O (0.249g, 0.001mol) was prepared in 1N H2SO4. Glycine
(0.750g, 0.001mol) and Phenanthroline (0.198g, 0.001mol) were dissolved separately in another
5.0ml of 1N H2SO4. The two solutions were then mixed properly to obtain a blue coloured
solution. The resulting solution was then stirred continuously for 1 hour at 700C. The precipitate
obtained was then filtered and washed with cold water (2 x 5.0ml) and then dried in the oven for
40 minutes to obtain a blue coloured complex. Yield = 0.3864g, 69.0% Anal. Calc.
C14H13N3SO6.H2OCu (Mol. Wt. 432.5): C, 38.84; H, 3.01; N, 9.71, S, 7.40. Found C, 38.598; H,
3.273; N, 7.764; S, 8.772. Reason for underestimated result for nitrogen mentioned above. IR
spectra of the complex shows absorption at 3442cm-1 υ (NH), 3049 cm-1 υ (C-H, aromatic),
1627cm-1 υ (c=o), 1586 cm-1 υ (C=N), 1549 cm-1, 1517 cm-1, 1424 cm-1 υ (C-C str), 1347 cm-1
υ (C-N str), 1213.47 cm-1 1104cm-1 υ (C-O str), 1047cm-1, 852cm-1, 620cm-1, 522 cm-1 υ (M-N),
407 cm-1 υ (M-O).
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2.4. Synthesis of (L-Prolinato)(1,10 – Phenanthroline) (Sulfonato) Copper(II) Tetrahydrate
A solution (5.0ml) of CuSO4.5H2O (0.249g, 0.001mol) was prepared in 1N H2SO4. L-Proline
(0.115g, 0.001mol) and Phenanthroline (0.198g, 0.001mol) were dissolved separately in another
5.0ml of 1N H2SO4. The two solutions were then mixed properly. The resulting solution was then
stirred continuously for 1 hour at 700C. The precipitate obtained was then filtered and washed
with cold water (2 x 5.0ml) and then dried in the oven for 40 minutes to obtain a blue coloured
complex. Yield, 0.2875g, 62.0%, Anal. Calc. C17H18N3SO6.4H2OCu (Mol. Wt.527.5): C, 38.67;
H, 3.41; N, 7.96, S, 6.07. Found C, 38.61; H, 3.273; N, 7.764 S, 8.468. IR spectra of the
complex shows absorption at 3434cm-1 υ (NH), 3020.42 cm-1 υ (C-H, aromatic), 1634.82 cm-1
υ
(c=o), 1586.21 cm-1 υ (C=N), 1553.79 cm-1, 1517.33 cm-1, 1424.15 cm-1 υ (C-C str), 1347.17
cm-1 υ (C-N str), 1213.47 cm-1 1106cm-1 υ (C-O str), 853cm-1, 720cm-1, 620 cm-1 υ (M-N), 405
cm-1 υ (M-O).
2.5. Hydroxylation of Phenol
1.0 ml of Phenol (~10 mmol) was taken in a 25 ml round bottom flask. Specific amount of
(refer to table-1) Chloro(glycinato) 1,10-phenanthroline copper(II) monohydrate was dissolved
separately in 2.0ml of distilled water and the resulting solution was transferred to the above
round bottom flask and mixed properly to obtain a homogeneous solution. 2.0 ml of 30%
H2O2was then added to the reaction mixture. An instantaneous reaction takes place. The reaction
mixture was then stirred at 600C for about 15 minutes. Product of the reaction mixture was then
extracted with 3 x 10 ml of diethyl ether. Progress of the reaction was monitored by using thin
layer chromatography. For all the four cases comparison of the product with authentic catechol
sample indicated exclusive formation of catechol from all the reactions. Final solvent was
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removed to obtain the final product. Reaction yields 63% of product Catechol. IR spectra of the
compound shows absorption at 3450.91 cm-1 ,3326.72 cm-1 υ (O-H stretching) , 3052 cm-1 ,
2961.52 cm-1 , 2924 cm-1 , 2851 cm-1 υ (C-H, aromatic), 2740 cm-1 , 2621 cm-1, 2465 cm-1, 2049
cm-1,1993 cm-1 , 1881.99 cm-1, 1746.04 cm-1, 1718.44 cm-1, 1602.00 cm-1, 1514.09 cm-1, 1363.93
cm-1, 1280 cm-1, 1241.81 cm-1, 849.13 cm-1, 802.68 cm-1, 754 cm-1, 636.96 cm-1, 564 cm-1,
13
499.17 cm-1 1H NMR (CDCl3) 5.52 (s, 2H) 6.74 - 6.79 (m, 4H); C{1H}(CDCl3) 116, 120,
149.
3. Results and discussion
3.1. Mixed Ligand Cu- Complex
Copper(II) complexes with N,N bonded and N,O bonded ligands have attracted significant
scientific interest for their industrial significance as efficient catalytic system. Many of such
complexes catalyze hydroxylation reaction of phenol. The mixed ligand Copper (II) complexes
were found to be useful for selective ortho-hydroxylation of phenol using water as solvent.
Reaction of Phenol with hydrogen peroxide in presence of catalytic amount of Chloro(Glycinato)
1,10-Phenanthroline Copper(II) monohydrate results in exclusive formation of catechol (equation
1). As stated above that was confirmed by comparison of the product with authentic catechol
sample in thin layer chromatography. Similar results were also obtained with other three mixed
ligand copper(II) complexes in water produces exclusively Catechol.
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OH
OH
OH
H2O2
Cu(II) catalyst
Equation - 1
.
Maximum yield obtained for such reaction is 63% with
Chloro(glycinato)(1,10 –
phenanthroline) copper(II) monohydrate as the catalyst. Yield of this reaction for different
catalysts are tabulated in table-1.
Yield of the product was found to be influenced by nature of the ligand and also it depends on
the reaction time. Allowing the reaction for longer time duration results in tar formation and
consequently decreases the yield of the product catechol.
Complexes of copper containing N,N (e.g., bipyridil16,22) or N,O ligands (Salen type and
bis(2-hydroxybenzyl) ethylenediamine type16) have been active in hydroxylation of aromatic
compounds by oxygen or hydrogen peroxide. These ligands form the (μ-ν2:ν2-peroxo)
dicopper(II) complexes that prove to be active toward selective hydroxylation of phenol23.
Copper ions can increase the selectivity of hydroxylation.
Catalytic decomposition of hydrogen peroxide by copper(II) complexes containing
phenanthroline and imidazole ligands were found to generate Cu(I)O2Cu(I) superoxide ion as
intermediate through catalytic decomposition of hydrogen peroxide24 Copper(I)regenerates
copper(II) again by the reaction with O2 and H2O2. The reaction of copper(II) and H2O2 also
generates peroxodicopper(II) [-Cu(II)-O-O-Cu(II)-].25,23 Based on these facts and keeping in
view the exclusive formation of catechol from the reactions, the following reaction mechanism
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can be depicted for selective hydroxylation of phenol (scheme-1). It can be observed from
scheme-1 that formation of hydroquinone from the reaction is only a rare possibility.
O
H2
N
Cl
N
N
II
Cu
H2
N
Cl
N
N
OH
H2O2
II
Cu
O
O
H
O
OH
O
O
H
Phenol
OH
-H2O
OH
Catechol
O
H2
N
Cl
N
N
II
Cu
OH
OH
O
OH
H
Scheme - 1
Formation of Catechol from the reactions was confirmed from FT-IR and NMR
spectroscopic data. The two broad absorption peaks observed in the region 3326.72cm-1 – 3450
cm-1 in FT-IR spectra of the product corresponds to the two –OH groups in the compound. The
1H-NMR spectra of the compounds shows one strong absorption at 5.52 which can be
attributed to the two –OH protons. Absorption due to the aromatic ring protons were observed as
complex multiplet in the region 6.74 - 6.79. The
1H-NMR spectra of catechol is given
below in figure-1.
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Copper is a very good coordinating metal which coordinates to a number of N (e.g.
phenanthroline) and O (e.g. carboxyls and hydroxyl groups) atoms. The reported
Chloro(Glycinato) Copper(II) monohydrate and other analogous mixed ligand Copper(II)
complexes were characterized by using CHN analysis and FT-IR spectroscopy as detailed in
experimental section. FT-IR Spectra of the complexes exhibits broad absorption in the region
3200-3363 cm-1which can be attributed due to N-H stretching in the complexes. The absorptions
around 3050-3053 cm-1 is due to aromatic C-H stretching, which indicates the presence of
aromatic ring i.e. phenanthroline, The presence of C=O group is evident from the observed peaks
around 1640 - 1690 cm-1. Absorption peaks due to Cu-O bond stretching was observed in the
region in the region 426-450 cm-1. Similarly absorption peak due to Cu-N bond stretching was
observed in the region 620-644 cm-1. Elemental analysis of the complexes also shows good
conformity to the structure assigned. However for heterocyclic compounds containing nitrogen
in the cycle or in the groups like azide, nitrile, nitro, etc. usually underestimated results are
obtained for nitrogen due to incomplete conversion of different forms of nitrogen to elemental
nitrogen. Due to this fact we have obtained underestimated results for the values of nitrogen in
elemental analysis. Thermogravimetric study of the complexes also supports the structures
assigned for the complexes.
3.2. Electroanalytical study of the complexes
Cyclic voltamograms for the four complexes were recorded and analyzed. For
Chloro(glycinato)(1,10 – Phenanthroline) Copper(II) monohydrate (1) [Figure 2(a)] and Chloro
(1,10 – Phenanthroline)(L-Prolinato) Copper(II) trihydrate (2) [figure-2(b)], the nature of the
voltamograms were found to be similar where one pair of current peaks is observed for both the
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cases. For (1) the pair of current peak observed in the range -0.77 to 0.53V and for (2), the pair
of peak observed in the range -0.65 to 0.35 V. The observed current peaks can be attributed to
the Cu(II) / Cu(I) redox process.
However in case of (Glycinato) )(1,10 –
Phenanthroline)(Sulfonato) Copper(II) Monohydrate [Figure 2(c)] (3) pair of peak was observed
in the range -0.53 to 0.19 V and for (L-Prolinato)(1,10-phenanthroline)(sulfonato) copper(II)
[Figure 2(d)] (4) we have not observed any significant anodic current peak. Absence of
significant anodic peak for (4) can be ascribed as irreversible reduction of Cu(II) center to Cu(I)
in the complex. The data obtained from the cyclic voltamograms for the four complexes(1), (2),
(3) and (4) from -1.0V to +1.0V are summarized in table-2.
For complexes(1) and (2), where only amine ligand was changed, comparison of the potential
values indicates that significant differences in the potential values of anodic peak potential.
Whereas for (3) and (4), where chloro ligands were exchanged for sulphonato ligand in (1) and
(2) respectively, marked differences in the redox behavior was observed. No significant redox
behavior is shown by (3) and (4). Therefore complexes (3) and (4) exhibit lesser catalytic
activity towards phenolic hydroxylation with maximum ‘Turn Over Number’ (TON) of 26.25 for
complex (3). In contrast complexes (1) and (2) which exhibit redox behavior shows better
catalytic activity towards phenolic hydroxylation with maximum TON of 78.25 for complex (1).
(1) and (2) exhibit one more cathodic current peak at around -0.2V for which corresponding
anodic current peaks were not observed. This might corresponds to some irreversible reduction
(Cu(II)/Cu(I).
4. Conclusion
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This study demonstrates that mixed ligand copper (II) complexes are efficient catalyst for
ortho hydroxylation of phenol by hydrogen peroxide in water. Particularly the regioselectivity
aspect of the catalytic system is an important point to emphasize. As far as yield is concerned,
Chloro(glycinato)(1,10 – Phenanthroline) Copper(II) monohydrate is the best among the four
catalysts. Apart from these facts, these reactions can be carried out in an ecofriendly solvent i.e.
water using again ecofriendly hydrogen peroxide as the oxidant. Therefore it can be concluded
that we have developed an environmentally benign catalytic system for synthesis of catechol.
Acknowledgement
Author sincerely acknowledges Department of Science & technology, Government of India
for financial support received under project grant (Project ID: DST / RFBR / P-221).
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Z. Tyeklar and K. D. Karlin, Acc. Chem. Res., 22, 241-248(1989).
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Figure-1: 1H NMR spectra of product Catechol in CDCl3
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(a)
(b)
(c)
(d)
Figure-2: Cyclic voltamograms of the complexes in acetonitrile solution containing 0.1M
tetraethyl ammonium tetrafluoroborate in the range of 1.0 to -1.0 with a current 1mA and a
scanning voltage of 50mV/s.
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Table-1: Yield of this reaction for different catalysts
S. No. Name of the catalyst
Phenol/catalyst
(mmol)
% yield of
catechol
Chloro(glycinato)(1,10 – Phenanthroline)
Copper(II) monohydrate
1.
10/0.08
10/0.11
10/0.16
10/0.08
63.0
52.0
49.0
44.0
Chloro(glycinato)(1,10 – Phenanthroline)
Copper(II) monohydrate
2.
Chloro(glycinato)(1,10 – Phenanthroline)
Copper(II) monohydrate
3.
Chloro (1,10 – Phenanthroline)(L-Prolinato)
Copper(II) trihydrate
4.
(glycinato)(1,10 – Phenanthroline)(Sulfonato)
Copper(II) Monohydrate
5.
10/0.08
21.0
(L-Prolinato)(1,10 – Phenanthroline)
(Sulfonato)Copper(II) Tetrahydrate
6.
10/0.08
10/0.23
20.0
22.0
7.
Cis-bisglycinato copper(II) monohydrate
Table-2: Data obtained from the Cyclic Voltamograms of the four complexes
Complex Epc1(V) Epa1(V)
∆Ep
Ipa/Ipc
-1.75
-2.4
(1)
(2)
(3)
(4)
-0.77
-0.65
-0.53
-0.82
0.53
0.35
0.19
0.92
-1.3
-1.0
-0.72
-1.74
-1.7
-0.7
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