CHAPTER V

IRON (Ill), MANGANESE (111) AND CHROMIUM (Ill) COMPLEXES OF

N, N" - DIETHYLENEAMINE - BIS ( 3 - CARBOXYPROPENAMIDE )

Han et al. reported the synthesis and antitumour activity of polyanion

platinum complexes containing acyclic amines, like diethylenetriamine as

ligands 178. Hu in 1997 also reported the studies on the antitumour activity of

antimony (Ill) triaminocarboxylic complexonates ·of diethylenetriamine penta

acetic acid205. Studies on metal complexes of maleic anhydride derivative of

diethylenetriamine, N, N" - diethyleneamine - bis (3 - carboxypropenamide)

(DEABCPH2) has not been carried out so far.

Present chapter deals with the preparation and characterization of

iron(III), chloride, bromide, thiocyanate, nitrate and perchlorate, chromium(III),

chloride and thiocyanate and manganese(III) acetate, chloride, bromide,

thiocyanate, nitrate, and perchlorate complexes of the ligand,

N, N" - diethyleneamine - bis (3 - carboxypropenamide), DEABCPH2, which is

prepared by the condensation of diethylene triamine with maleic anhydride.

Experimental

The details of the preparation of the ligand and the purity of the reagents

used are described in chapter II.

Preparation of the iron (Ill) complexes with DEABCPH2

1. Iron (111) chloride and bromide

A solution of the metal salt (0.01 mole) was prepared in methanol. A hot

aqueous methanolic solution of the sodium salt of the ligand (0.01 mole) was

added to the above solution. The resulting solution was stirred well and kept

for settling down the precipitate. The brown solid complex was filtered,

washed several times with methanol and finally dried over P 4010.

125

2. Iron (Ill) nitrate

An aqueous solution of the sodium salt of DEABCPH2 (0.01 mole) in

methanol was added to a solution of iron (Ill) nitrate (0.01 mole) in methanol.

The resulting solution was refluxed on a water bath for about one hour. On

concentrating the solution, a brown solid complex separated. It was filtered,

washed several times with methanol and finally dried over P 4010.

3. Iron (111) thiocyanate

An ether solution of iron (Ill) thiocyanate (0.01 mole) was mixed with the

solution of sodium salt_ of DEABCPH2 (0.01 mole) in aqueous methanol. The

resulting brown precipitate formed was filtered, washed several times with

ether and methanol and dried over P 40 10.

4. Iron (Ill) perchlorate complex

An aqueous methanolic solution of sodium salt of the DEABCPH2

(0.01 mole) was added to methanolic solution of iron (Ill) perchlorate

(0.01 mole). The resulting solution was refluxed on a water bath for about one

hour. The reddish brown precipitate separated on concentration was filtered,

washed with methanol and dried over P 4010.

Preparation of manganese (111) complexes with DEABCPH2

1. Manganese (Ill) acetate complex

A hot aqueous methanolic solution of 0.01 mole sodium salt of the ligand,

DEABCPH2 was added to 0.01 mole of manganese (Ill) acetate dihydrate in

methanol. The resulting mixture was refluxed on a water bath for about three

hours. The brownish black precipitate formed was filtered, washed with

methanol and dried over P 4010.

2. Manganese (111) chloride, bromide, nitrate and perchlorate complexes

0.01 mol of manganese (Ill) acetate dihydrate was dissolved in methanol.

To this 0.01 mole of lithium chloride, bromide, nitrate or perchlorate in

methanol was added. To the resulting solution 0.01 mole hot aqueous

126

methanolic solution of the sodium salt of the ligand, DEABCPH2 was added

and refluxed on a water bath for about two hours. The resulting solution was

concentrated on a water bath. On cooling, a brownish black solid separated. It

was filtered, washed several times with methanol and dried over P 4010.

3. Manganese (111) thiocyanate complex

A hot aqueous methanolic solution of 0.01 mole sodium salt of the

DEABCPH2 was added to 0.01 mole of manganese (Ill) acetate dihydrate in

methanol containing about 1 g of ammonium thiocyanate. The resulting

mixture was refluxed on a water bath for three hours. The brownish black

precipitate formed was filtered, washed several times with methanol and dried

over P4010.

Preparation of chromium (Ill) complexes with DEABCPH2

1. Chromium (Ill) chloride complex

A hot aqueous methanolic solution of the sodium salt of the DEABCPH2

(0.01 mole) was added to a solution of the chromium (Ill) chloride (0.01 mole)

in methanol. The resulting mixture was refluxed on a water bath for two hours.

The grey precipitate formed was filtered, washed with methanol and dried

over P4010.

2. Chromium (111) thiocyanate complex

To a solution of the chromium (Ill) chloride (0.01 mole) in methanol about

1 gm of ammonium thiocyanate was added. A hot aqueous methanolic

solution of sodium salt of the ligand, DEABCPH2, (0.01 mole) was added to

this solution. The resulting mixture was refluxed on a water bath for about two

hours. The violet crystalline precipitate formed was filtered, washed several

times with methanol and dried over P 4010.

Some general properties of the complexes

All the complexes are stable at room temperature and non-hygroscopic.

The complexes are only slightly soluble in methanol and ethanol and insoluble

127

in common organic solvents like ether, acetone, benzene, carbon tetrachloride

and nitro benzene but are freely soluble DMF, DMSO and acetonitrile. Dark

brown or reddish brown iron (Ill) complexes and grey coloured chromium (Ill)

chloride complex of DEABCPH2 were obtained as fine powder. The

chromium (Ill) thiocyanate complex is violet in colour and is found to be

crystalline in nature. All the manganese (Ill) complexes of DEABCPH2 are

brownish black in colour and obtained as microcrystalline powder in high yield.

ANALYSIS

Metal percentage in the complexes was estimated as described in

chapter Ill. Manganese was estimated by spectrophotometric method.

Peaceful pyrolysis was adopted for the estimation of iron in perchlorate

complex256. The chloride and bromide were estimated by Volhard's

method254. Kurz's method was employed to estimate perchlorate255

. The

complexes were analysed for carbon, hydrogen and nitrogen on a Carlo Erba

elemental analyser. Sulphur in thiocyanate complex was oxidized to sulphate

and determined as barium sulphate254. Details of the procedures are given in

chapter II.

PHYSICAL MEASUREMENTS

The molar conductance values of the complexes in DMF, acetonitrile and

methanol were measured using Systronic direct reading type conductivity

meter. The magnetic susceptibilities were determined at room temperature by

Gouy method or on a Vibrating Sample Magnetometer (VSM) PAR model 155

at RSIC, IIT Madras. The infrared and electronic spectral studies, X-ray

powder and thermal studies were carried out as described in chapter II.

RESULTS AND DISCUSSION

The analytical data and empirical formulae of the complexes are

presented in Table 5.1. The data indicate that the complexes can be

represented as Fe (DEABCP) X (X = Cl, Br, NCS, N03 or CI04 ) ,

128

Mn (DEABCP) Y (Y = Cl, Br, NCS, N03, CI04 or CH3COO) and

Cr (DEABCP)Z ( Z = Cl or NCS).

Electrical Conductance

The molar conductance values of the complexes in DMF, acetonitrile and

methanol using approximately 10-3M solutions were determined at room

temperature. The results are given in Table 5.2. The molar conductance

values expected for 1 :1 electrolytic behaviour in DMF, acetonitrile and

methanol are 65-90, 120-170 and 80-115 Ohm· 1 cm2 moi- 1 respectively262• 263·

All the above complexes are found to be non-electrolytes in DMF, acetonitrile

and methanol.

Infrared spectra

The important ir spectral bands of the free ligand, DEABCPH2 and

its iron (Ill), chromium (Ill) and manganese (Ill) complexes are given in

Tables 5.3 and 5.4.

The ir spectrum of the free ligand DEABCPH2 shows a weak band at

3320 cm·1 and a strong band at 3300 cm·1, which are assigned to the NH

stretching frequencies of the secondary amino and secondary amide groups

respectively247•

251. The broad band at 3100 cm· 1 is assigned to the OH

stretching vibration of the carboxylic acid groups246. The low value of the OH

stretching vibration indicates the possibility of intramolecular hydrogen boding

with oxygen atom of the amide groups (-OH- - - -O=C<) in the molecule 265• 266.

A strong band observed at 1715 cm· 1 in the free ligand is assigned to

Yas(C=O) of the carboxylic acid groups 167•

248•

249. Another strong band at

1625 cm·1 in the spectrum of the free ligand, assignable to vc=o of the

secondary amide groups, remains almost unchanged in the

complexes 167• 250•267, indicating non-participation in complexation.

Halide complexes

In the iron (111), chromium (Ill) and manganese (Ill) halide complexes of

DEABCPH2 . the NH stretching frequency band is observed around

129

3210-3220 cm·1, showing that coordination has occurred through nitrogen

atoms of both the amide groups 268• 269. The characteristic carboxylic group

absorption band at 1715 cm· 1 disappears and two new bands at -1595 cm· 1

and -1410 cm· 1 are observed in the complexes, which may be assigned to

asymmetric and symmetric stretching frequencies respectively of the

coordinated carboxylate groups 270 •

273. The strong band observed at

1625 cm· 1 in the ir spectrum of the tree ligand is assigned to stretching

frequency of carbonyl group of secondary amide. This band is noted almost at

the same position in the ir spectra of the complexes, indicating non­

participation of amido oxygen in complex formation 167• 267.

The band at 3320 cm· 1 in the ir spectrum of free ligand assigned to NH

stretching frequency of secondary amino group is observed at -3280 cm· 1 in

the complexes, indicating the participation of nitrogen atom of the secondary

amino group in coordination251. From the above observations it may be

concluded that in these complexes the ligand is pentadentate, coordination

sites being the amino nitrogen, two amido nitrogen and two oxygen atoms of

carboxylate groups. The halide ions are also coordinated to the metal ion as

evidenced by the non-electrolytic nature of the complexes.

The bands observed in the regions 550-570 cm· 1 and 450-470 cm· 1 in the

ir spectra of the complexes are assigned to VM-N and YM-o respectively 274• 275.

Perchlorate complexes

The ir spectrum of iron (Ill) and manganese (Ill) perchlorate complexes

shows that in this case also DEABCPH2 acts as a penta dentate ligand. The

band near 3285 cm· 1 in the ir spectra of iron (Ill) and manganese (111)

complexes indicates the participation of amino nitrogen in coordination. The

strong bands near 3225 cm· 1 in the spectra of complexes indicate the

involvement of amide nitrogen in complexation. The characteristic carboxylic

group absorption band at 1715 cm· 1 disappears and two strong bands, one at

1600 cm· 1 and other at 141 O cm· 1 in the case of iron (111) and 1595 and

130

1415 cm- 1 in the case of manganese (Ill) complexes, are observed. These are

assigned respectively to Vas (OCO) and Vs (OCO) of coordinated carboxylate

groups. The strong band observed at 1625 cm·1 in the ir spectrum of the

ligand, assigned to vco of amide does not undergo significant shift in the ir

spectrum of complexes. Therefore it may be concluded that carbonyl group of

amide is not involved in coordination to the metal ions.

The perchlorate complexes under study show few additional bands,

which are attributable to coordinated perchlorate group. The strong band

observed at -1115 cm· 1 and another medium band -1090 cm· 1 are assigned

to v4 and v 1 of monodentate perchlorate group. Similarly, two bands of

medium intensity, occurring around 660 and around 640 cm· 1 in the case of

iron (Ill) and around 665 and 645 cm· 1 in the case of manganese (Ill)

complexes are assigned respectively to the v3 and v5 of coordinated CI04·.

The weak band observed around 940 cm· 1 in the iron (111) and manganese (Ill)

complexes can be attributed as v2 band of the coordinated perchlorate group.

The v5 vibration expected around 480 cm· 1 for coordinated perchlorate could

not be located since the metal ligand stretching frequencies are also expected

in this region. The position of bands in the region 1150-1080 cm-1 and

700-620 cm·1 and the magnitude of separation between them suggest the

monodentate nature for the coordinated perchlorate group (C3v) in these

complexes. The conductance data are also in support of the non-ionic nature

of the perchlorate group and is therefore coordinated to the metal ions.

Nitrate complexes

The ir spectra of iron (Ill) and manganese (Ill) nitrate complexes of

DEABCPH2 show bands assignable to the coordinated nitrate groups. The

strong band observed at -1385 cm·1 and another medium band at -1460 cm· 1

in the complexes are assignable to the split components of v3. The nitrate

complexes of iron (Ill) and manganese (Ill) also show two weak bands in the

region 1700-1800 cm·1. These bands are observed at 1785 and 1770 cm· 1 for

131

the iron (Ill) complex, 1760 and 1755 cm· 1 for the manganese (Ill) complex.

These bands are attributed to the combination bands (v1+v4), which also

support the monodentate nature of the nitrate group287. The bands observed

at -825 cm· 1 for the iron (Ill) and manganese (111) nitrato complexes are

assigned to non-polar rocking vs vibration.

Evidences are available from ir spectra of the nitrato complexes to show

that the ligand, DEABCPH2 , is penta dentate. A strong band near 3215 cm·1

in the ir spectra of iron (Ill) and manganese (Ill) complexes indicates the

involvement of amide nitrogen in coordination. The characteristic carboxylic

group absorption at 1715 cm·1

disappears and two strong bands, one at

1595 cm· 1 and other at 1415cm·1

in the case of iron (Ill) and 1585cm·1 and

1410 cm· 1 in the case of manganese (Ill) complexes, are observed. These are

assigned respectively to Vas (OCO) and vs (OCO) of coordinated carboxylate

groups. The band around 3320 cm·1 in the free ligand, due to VNH of

secondary amino group, is shifted to -3280 cm· 1 in the complexes indicating

the participation of secondary amino group in complexation. The strong band

observed at 1625 cm·1 in the ir spectrum of the ligand and assigned to vco of

amide does not undergo significant shift in the spectra of complexes.

Therefore it may be concluded that carbonyl groups of amide are not involved

in coordination to the metal ion.

Acetate complex

The ir spectrum of the manganese (Ill) acetate complex shows that the

ligand DEABCPH2 is pentadentate, the coordination sites being the amino

nitrogen, two amido nitrogen and the two oxygen atoms of the carboxylate

groups. The strong band observed at 1625 cm·1 in the ir spectrum of the

ligand is assigned to stretching frequency of carbonyl group of amide. This

band is found almost unchanged in the spectrum of the complex, indicating

non-involvement of amido oxygen in coordination. The NH stretching

frequency of the secondary amino group is observed at 3275 cm·1. The band

132

at 3210 cm-1 is assigned to the VNH of amide groups. The asymmetric and

symmetric stretching vibration of the coordinated carboxylate groups are

observed at 1590 and 1410 cm- 1 respectively. The different modes by which

the acetate group can coordinate to the metal are discussed in chapter Ill. In

the present investigation, the nature of the acetate group in the

manganese (Ill) acetate complex of DEABCPH2 cannot be predicted from the

ir spectra alone because there are ligand transitions in the same region where

carboxyl group vibration are also expected. However, the coordinated nature

of the acetate ion is confirmed from the conductivity measurements.

Thiocyanate complexes

Evidences are available from infrared spectra of the thiocyanate

complexes to show that in this case also the ligand, DEABCPH2 acts as

pentadentate. Strong bands near 3215 cm- 1 in the spectra of iron (Ill),

chromium (111) and manganese (Ill) complexes indicate the involvement of

amido nitrogen in coordination. The Vas (OCO) and Vs (OCO) of coordinated

carboxylate groups are observed at -1585 and -1415 cm- 1 respectively. The

energy separation between the bands, l:,.v (OCO) is -170 cm- 1• The strong

band at 1625 cm-1 in the ir spectrum of the ligand is assigned to stretching

vibration of C=O group of amide. This band is noted almost at the same

position in the complexes, indicating non-participation of amido oxygen in

coordination. The weak band at -3320 cm- 1 in the spectrum of the free ligand

assigned to NH stretching frequency of secondary amino group is shifted to

around 3280 cm- 1 in the complexes, implying that the amino nitrogen is also

coordinated to the metal ions.

The thiocyanate complexes show few additional bands that are not

present in the ir spectra of the ligand as well as of the other complexes. Very

strong band observed at 2065, 2080 and 2055 cm- 1 in iron (Ill), chromium (Ill)

and manganese (Ill) thiocyanate complexes respectively are assignable to

vc-N of thiocyanate group. The C-S stretch could not be identified since the

ligand itself has bands in that region. Hence the NCS bending vibration is

133

used for ascertaining the coordination sites. The medium band observed at

475, 485 and 470 cm-1

respectively are assignable to the NCS bending

vibration. This clearly indicates that thiocyanate group is coordinated through

nitrogen. The conductance data also reveal the non-ionic nature of the

thiocyanate group.

Magnetic behaviour

The magnetic susceptibility, diamagnetic corrections and

effective magnetic corrections and effective magnetic moments of iron (Ill),

chromium (111) and manganese (Ill) complexes of DEABCPH2 are presented in

Table 5.5.

For high-spin iron (Ill) complexes, the spin only value of 5.92 BM may be

decreased as a result of greater splitting of the 5T 2 state or the presence of

antiferromagnetic coupling between two metal atoms320-325

.

In the present study, the magnetic moment values of [Fe(DEABCP)X],

where X= Cl, Br, NCS, N03 or CI04, are found to be in the range

4.49-5.32 BM. The lower values observed for iron (111) complexes suggest the

presence of considerable antiferromagnetic interactions in them.

The magnetic moments of chromium (Ill) complexes are expected to be

close to the spin only value of 3.88 BM. However, the magnetic moment

values for monomeric chromium (Ill) complexes were reported in the range

3.5 - 4.0 BM327-329

. The deviation from the spin only value is explained in

terms of coupling between the two paramagnetic (8=3/2) chromium (Ill)

centers. In the present study, the magnetic moment values observed for the

complexes, [Cr(DEABCP)CI] and [Cr(DEABCP)NCS] are 3.74 and 3.68 BM

respectively. This corresponds to three unpaired electrons. The deviations

from the theoretically expected value show the presence of metal-metal

interactions in these complexes.

For the manganese (Ill) high-spin octahedral complexes, the magnetic

moments differ from the spin only value for four unpaired electrons (4.9 BM)

134

by the factor (1 -�J , Where "A - spin orbit coupling constant due to theIODq -

mixing of 5T29 and 5Eg states. With a value of 90 cm-1 for A, the magnetic

moment calculated for an octahedral high-spin complex is reported to

be 4.8 BM and for low-spin complexes with A= -180 cm-1, the magnetic

moment is 3.5 BM257.

The present manganese (Ill) complexes, [Mn(DEABCP)Y], where Y = Cl,

Br, NCS, N03, CI04 or CH3COO, the magnetic moments are close to the spin

only value expected for four unpaired electrons (4.9 BM). However, the nitrate

and acetate complexes show lower values, 4.46 and 4. 78 BM respectively.

This lowering can be attributed to the presence of antiferromagnetic

interactions in these complexes. It is worthwhile to carry out the magnetic

moment measurements at different temperatures to ascertain the nature of

magnetic behaviour of these complexes. Such an investigation could not be

carried out due to lack of facilities.

Electronic spectrum

The electronic spectral bands of the complexes in DMF solution and their

probable assignments are given in Tables 5.6, 5.7 and 5.8.

The iron (Ill) complexes, [Fe(DEABCP)X] (X= Cl, Br, NCS, N03 or CI04),

show bands at around 33,330 , 27,780 and 26,315cm-1, which are assigned

to charge transfer bands. The high spin Fe (Ill) complexes with d5

configuration have the ground state 6A19 and all d-d transitions are

spin and Laporte forbidden334. Hence rather weak bands with extinction

coefficient, s = 0.01 - 0.1, are observed in such systems. The weak broad

band with maximum at around 20,370 cm·1 is assigned to spin forbidden

transition 6A19 74T19.

The expected spin allowed d-d transitions for octahedral chromium (Ill)

complexes are 4A297 4T29, 4A297 4T, 9(F) and 4A2

97 4T,9(P). The electronic

spectra of present chromium (Ill} complexes, [Cr(DEABCP)Z] (Z = Cl or NCS),

135

show strong bands with maximum at around 33,330 and 26,670 cm-1, whichare assigned to charge transfer bands. The 4A29 74T19

(P) transition

is probably obscured by the charge transfer band maxima at 26,670 cm-1.

The weak bands with maxima appearing at 21,665 cm-1 and at around

16,170 cm-1, for the halide complex, [Cr(DEABCP)CI], are assigned to the 4A29

7 4T19(F) and 4A2974T2

9(F) transition respectively. The broad band with

maximum at 17,880 cm-1 in the thiocyanate complex [Cr(DEABCP)NCS] is

assigned to the 4A297 4T19

(F) transition. The 4A297 4T19

(F) transition in this

case may be overlapped with 4A297 4T� (F) and hence could not be located.

The d-d transition, 5E975T29, is the only one expected electronic

transition for octahedral manganese (Ill) complexes. However, high spin

octahedral Mn (Ill) complexes are susceptible to Jahn-Teller distortion. Hence

the electronic spectra of manganese (111) complexes usually show two or three

bands in the visible region 340-343

• The electronic spectra of present

manganese (Ill) complexes, [Mn(DEABCP)Y] (Y= Cl, Br, NCS, N03, CI04 or

CHCOO), show two medium intensity broad bands with maxima at 33,335 and

27,775 cm-1, which are assigned as charge transfer bands. The broad band

with maximum at -18690 cm-1 is attributed to 5E9

7 5T 29. The nitrate

complex of manganese (Ill) shows a shoulder at -17595 cm- 1. This

absorption may be due to the electronic transition between the split

components of the 5T29 and 5E9 levels of the distorted octahedral complex.

X-ray powder diffraction study of [Fe (DEABCP) Cl]

The x-ray powder pattern of the iron (Ill) complex, (Fig 5.4), was taken on

Philips PW 1710 ray powder diffractometer in chart recorder. A sample spinner was used to remove the effect of orientation. Reflections from various sets of planes have been recorded for 50 to 70° at a sample rotation 0.05°/sec with Co Ka(A=1.7902 A) radiation using 40KV20MA. All the lines, by employing Hesse and Lipson's procedure344

-345

, could be indexed successfullyfor the orthorhombic system.

136

The sin28 difference value 0.0073, occurring eleven times in the sin28

difference chart, was taken as the reflection from (001) plane. This penacoidal

reflection is present in the experimental sin28 values. The sin28 difference

value 0.0176 was chosen as the reflection from (020) plane and occurs six

times in the sin28 difference value chart. Then the sin28 value from (010) plane

will be 0.0044, which occurs four times in the sin28 difference value chart.

This penacoidal reflection is not present in the observed sin28 values but the

higher order reflection (020) is present in the experimental sin28 values. The

value 0.0092 which occurs seven times in the sin28 difference chart was

chosen as the reflection from (200) plane. Then the sin28 value for (100)

plane will be 0.0023 and it occurs two times in the sin28 difference chart. This

penacoidal reflection is not present in the experimental sin28 values.

However, the higher order reflection (200) and (500) are present in the

observed sin28 values. Using these lattice constants, A=0.0023, B=0.0044

and C=0.0073, all the thirty - five lines of the powder pattern of the Fe (Ill)

complex could be indexed successfully for orthorhombic system. The

observed and calculated sin28 values together with their relative intensities are

given in Table 5.9.

By successfully substituting the values of sin28(1oo), sin28(010) and sin28(001)

in the relation,

·2 2 2 2 � � � S1n 8 (hk1)=A h + B k + C I where, A= -2

, B = -2

andC = -2

4a 4b 4c

the unit cell dimensions a, b and c for the complex were calculated. The

values are 18.6642A, 13.4942A and 10.4764A respectively. The unit cell

volume for the orthorhombic system V = a b c = 2.638 6x10"2 cm3• The density

of the Fe (Ill) complex, d = 0.9675 g/cm3. The molecular mass of the complex

M = 388.

137

dNoV .9675x6.023x1023 x2.6386xl0-21

n = -- = --�--.:..._:___�...:___:__:__

M 388

= 3.96 � 4

The number of molecules per unit cell is calculated and found to be four.

The presence of four molecules per unit cell confirms the correctness of our

assumption. The diffraction pattern of Cr (Ill) and Mn (Ill) complexes showed

only very few lines of weak intensity so they could not be analysed.

SUMMARY

Iron (Ill), manganese (Ill) and chromium (Ill) complexes with the ligand

DEABCPH2 having formulae [Fe(DEABCP)X] (X = Cl, Br, NCS, N03 or CI04),

[Mn(DEABCP)Y] (Y= Cl, Br, NCS, N03, CI04 or CH3COO)and [Cr(DEABCP)Z]

(Z = Cl or NCS), were synthesized and characterized using physicochemical

studies. The molar conductance values in DMF, acetonitrile and methanol and

the ir spectral values show that all the complexes are non-electrolytes. Hence

the anions are also coordinated to the metal ion. Infrared spectra of

complexes show that DEABCPH2 behaves as a divalent pentadentate ligand

coordinating through the amino nitrogen, two amido nitrogen and two oxygen

atoms of the carboxylate groups. The magnetic moment values suggest that

all the complexes are high-spin type. Lower value of magnetic moments

obtained for iron (Ill) complexes and manganese (Ill) nitrate and acetate

complexes suggest anti-ferromagnetic interactions in them. From the

electronic spectral data it is concluded that all the three metal ions, Fe (Ill),

Cr (Ill) and Mn (Ill), have octahedral environment.

X - ray powder diffraction study of a typical sample, [Fe(DEABCP)CI],

was also done to ascertain the crystalline nature and to determine the unit cell

parameters. It is found to be orthorhombic with the unit cell dimensions,

a= 18.6642A, b = 13.4942A and c = 10.4764A

Analytical, spectral and magnetic studies suggest that the possible

structures of the complexes are as given in the next three pages.

X

/HN

�

C H2

/

C H, NH "c

,f'o

c� \

I C H

C H2

/

Fe- II

>N

� C;

H

o==c

�

\H /0

0

�C H --c

11 Fig. 5.1

0 X = Cl, Br, NCS, N0

3 or C10

4

l;.)

00

y

0

/HN-CH

2 CH

2-NH" �

CH2 �

, /

C

\

I � CH

CH2

/

M\ �

H

\HN ""' /

/ o c�

o-c �o

Fig. 5.2

\CH /O

�CH-�

O Y = Cl, Br, NCS, N03

, CIO 4

or CH3COO

, .�

z

/HN

�

CH2

CH2

- NH

�#

O

_ CH

2

/

\.

I . CH

CH, /c,- . II

\ HN

� )H

o-c/o c�

\H /0

0

�cH --c

11 0 Fig. 5.3 Z= Cl or NCS

-

Table 5.1 Some physical and analytical data of DEABCPH2 and its Fe(III) , Cr(III) and Mn(III) complexes SI. Emperical Colour Found {calculated}% No. formula M C ·H N Cl/Br S/C104

1 C12H17N30a White - 48.22 5.61 13.96

[DEABCPH2] - (48.16) (5.69) (14.05)

2 Fe(DEABCP)CI Deep 13.97 36.9 3.74 10.93 9.05

Brown (14.38) (37.08) (3.86) (10.82) (9.13)

3 Fe(DEABCP)Br Dark 12.68 33.05 3.33 9.54 18.29

Brown (12.91) (33.28) (3.47) (9.70) (18.46)

4 Fe(DEABCP)NCS Reddish 13.36 37.69 3.55 13.77 - 7.84 -

Brown (13.59) (37.97) (3.65) (13.63) - (7.79)

5 Fe(DEABCP)N03 Brown 13.92 34.57 3.48 13.43

(13.46) (34.71) (3.62) (13.50)

6 Fe(DEABCP)CI04 Reddish 12.04 31.68 3.24 9.11 - 22.01

brown (12.35) (31.84) (3.32) (9.28) - (21.99)

7 Cr(DEABCP)CI Grey 13.71 37.35 3.78 10.81 9.29

(13.53) (37.46) (3.90) (10.92) (9.22)

8 Cr(DEABCP)NCS Violet 12.67 38.08 3.54 13.58 - 7.65

(12.78) (38.33) (3.69) (13.76) - (7.86)

Table 5.1 {contd .... }

SI. Emperical Colour Found (calculated)% �-

No. formula M C H N Cl/Br S/C104

9 Mn(DEABCP)CI Brownish 13.98 37.26 3.68 10.98 9.02

black (14.18) (37.17) (3.87) (10.84) (9.15)

10 Mn(DEABCP)Br Brownish 12.61 33.17 3.40 9.65 18.32

black (12.72) (33.35) (3.47) (9.73) (18.50)

11 Mn(DEABCP)NCS Brownish 13.27 37.96 3.54 13.75 - 7.94 N

black (13.40) (38.05) (3.66) (13.66) - (7.81)

12 Mn(DEABCP)N03 Brownish 13.36 34.62 3.48 13.43

black (13.27) (34.79) (3.62) (13.53)

13 Mn(DEABCP)Cl04 Brownish 12.06 31.68 3.14 9.22 - 21.94

black (12.18) (31.90) (3.32) (9.30) - (22.03)

14 Mn(DEABCP)CH3COO Brownish 13.06 40.64 4.14 10.07

black (13.37) (40.88) (4.38) (10.22)

Table 5.2 Molar conductance values of Fe(III), Cr(III) and Mn(III) complexes of DEABCPH 2

Dimeth;tl formamide Acetonitrile Methanol SI. Complex Concn� Molar Concn. Molar Concn. Molar Assignment

No. x1 ff3M Conductance* x1 f

f3M Conductance* x1 ff3M Conductance*

1 [Fe(DEABCP)CI] 1.23 15.5 0.98 32.1 1.07 13.9 non-electrolyte

2 [Fe(DEABCP)Br] 1.00 28.3 0.95 29.6 0.99 28.7 non-electrolyte

3 [Fe(DEABCP)NCS] 1.20 29.4 1.11 21.8 1.21 35.5 non-electrolyte

4 [Fe(DEABCP)N03] 1.14 11.0 0.97 26.4 1.13 17.6 non-electrolyte

5 [Fe(DEABCP)C104] 1.04 10.1 1.01 23.6 1.07 9.2 non-electrolyte

6 [Cr(DEABCP)CI] 1.04 15.2 1.12 19.1 1.21 15.3 non-electrolyte

7 [Cr(DEABCP)NCS] 1.08 12.6 1.14 27.6 1.06 19.1 non-electrolyte

8 [Mn(DEABCP)CI] 1.06 27.5 1.05 29.0 1.08 19.6 non-electrolyte

9 [Mn(DEABCP)Br] 1.02 25.8 1.04 34.8 1.00 26.7 non-electrolyte

10 [Mn(DEABCP)NCS] 1.12 18.8 0.96 28.7 1.03 30.5 non-electrolyte

11 [Mn(DEABCP)N03] 1.04 27.3 1.02 25.3 1.10 32.1 non-electrolyte

12 [Mn(DEABCP)Cl04] 0.94 21.6 1.02 24.7 0.95 32.4 non-electrolyte

13 [Mn(DEABCP)CH3COOO] 0.95 32.1 1.03 24.6 1.09 15.8 non-electrolyte

*Ohm-1 cm2 mor1

Table 5.3 Infrared spectral bands (cm-1) of DEABCPH2(L"' �) and its Fe(III) and Cr(III) complexes

DEABCPH2(L"' �) [Fel"' Cl] [Fel'" Br] [Fel'" NCS] [Fel'" N03] [Fel"' Cl�] [Crl"' Cl] [Crl"' NCS] Tentative Assignments

3320(w) 3280(s) 3285(s) 3280(s) 3280(s) 3285(s) 3285(s) 3285(s) VNH of sec.amine

3300(s) 321 S(b) 3210(s) 321 S(s) 321 S(s) 3225(s) 321 S(b) 3225(s) VNH of sec.amide

31 OO(b) voH of the carboxylic acid

2460(w) 2460(w) 2460(w) 2460(w) 2460(w) 2460(w) 2460(w) 2460(w)

2350(w) 2350(w) 2355(w) 2350(w) 2350(w) 2350(w) 2350(w) 2355(w)

2065(s) 2080(w) vc-N (Thiocyanate)

1900(w) 1900(w) 1900(w) 1900(w) 1900(w) 1900(w) 1900(w) 1900(w) 1785(w) v1 + v4 N03 coordinated

1770(w) 1715(s) vc=o of carboxylic acid

1625(s) 1623(s) 1622(s) 1623(s) 1623(s) 1624(s) 1622(s) 1624(s) vco of amide I band

1590(s) 1595(s) 1585(s) 1595(s) 1600(s) 1605(s) 1590(s) vco asym. of coordinated

carboxylate group

1570(s) 1550(s) 1550(s) 1555(s) 1550(s) 1560(s) 1550(s) 1550(s) VNH inplane amide II band

1460(m) v 4 N03 coordinated

1410(s) 1405(s) 1410(s) 1415(s) 1410(s) 1415(s) 1415(s) vCO sym. of coordinated

carboxylate group 1385(s) v 1 N03 coordinated

1365(s) 131 S(m) 1320(s) 1315(s) 131 S(w) 1320(s) 131 S(m) 1315(s) VCN + NH bending

amide Ill , combination band

1220(w) 1215(w) 1220(w) 121 S(w) 1215(w) 1220(w) 1215(w) 1215(sh)

� �

Table 5.3 {contd ...... } DEABCPH2(L'" H2} [Fel"' Cl] [Fel"' Br] [Fel"' NCS] [Fel'" N03] [Fel'" CIOi] [Crl'" Cl] [Crl'" NCS] Tentative Assignments

1115(s) v4 CI04 coordinated

1090(m) v 1 CI04 coordinated

1060(w) 1060(w) 1060(w) 1060(w) 1065(vw) 1060(w) 1065(w) 1055(w) 1035(m) V2 N03 coordinated

990(m) 990(m) 1 OOO(m) 990(w) 995(w) 990(w) 985(w) 990(w)

950(w) 950(w) 950(w) 950(w) 950(w) 950(w) 955(w) 950(w) 940(w) v2 CI04 coordinated

885(w) 885(w) 890(w) 885(w) 890(w) 885(w) 885(w)

860(m) 860(w) 860(w) 860(w) 860(w) 860(w) 860(w) 860(w) 825(s) v6 rocking of N03

785(w) 785(w) 785(w) 785(w) 785(w) 785(w) 785(vw) 785(w)

690(w) 685(w) 680(w) 680(w) 685(w) 680(w) 690(w) 660(m) v3 CI04 coordinated

640(m) v5 CI04 coordinated

565(w) 570(m) 565(m) 570(w) 570(w) 565(w) 565(w) VM-N

520(w) 520(w) 525(w) 520(w) 525(w) 520(w) 520(w) 520(w)

475(m) 485(m) Ncs deformation

460(w) 465(w) 450(w) 460(m) 455(w) 470(w) 465(w) VM-0

s=strong, vs=very strong, m = medium, b = broad, w = weak, vw = very weak, mb = medium broad and sh = shoulder

Table 5.4 Infrared spectral bands (cm-1) of DEABCPH2(L"' �) and its Mn(III) complexes

DEABCPH2(L"' �) [Mnl"' Cl] [Mnl'" Br] [Mnl'" NCS] [Mnl"' NOa] [Mnl"' CI04] [Mnl"' C�COO] Tentative Assignments

3320(w) 3285(w) 3285(w) 3283(s) 3280(w) 3285(w) 3275(s) VNH of sec. amine

3300(s) 3215(b) 3210(s) 3245(s) 321 S(s) 3225(s) 321 O(b) VNH of sec. amide

31 OO(b) voH of the carboxylic acid

2460(w) 2460(w) 2460(w) 2460(w) 2460(w) 2460(w) 2460(w)

2350(w) 2355(w) 2350(w) 2350(w) 2350(w) 2350(w) 2350(w)

2055(s) vc-N (Thiocyanate)

1900(w) 1900(w) 1900(w) 1900(w) 1900(w) 1900(w) 1900(w) 1760(w) v1 +v4 N03 coordinated

1755(w)

171 S(s) vc=o of carboxylic acid

1625(s) 1624(s) 1622(s) 1623(s) 1622(s) 1623(s) 1622(s) vc=o of amide I band.

1590(s,br) 1595(s) 1585(s) 1585(s) 1595(s) 1590(s) vc=o asy. Of coordinated

carboxylate group

1570(s) 1550(s) 1540(s) 1555(m) 1 SSO(s) 1 SSO(s) 1545(s) VNH inplane amide II band

1445(m) v4 N03 coordinated

1410(s) 1410(s) 1415(s) 1410(s) 1415(s) 1410(s) vco sym. of coordinated

carboxylate group

1385(vs) v, N03 coordinated

1365(s) 1320(m) 1320(m) 1305(m) 131 S(m) 1320(m) 1300(m) VCN + NH bending

amide Ill , combination band

1220(w) 1215(w) 1220(w) 121 S(w) 1220(w) 121 S(w) 121 S(w)

Table 5.4 {contd ...... }

DEABCPH2(L'" �) [Mnl"' Cl] [Mnl"' Br] [Mnl"' NCS] [Mnl"' NOJ] [Mnl"' CI04] [Mnl'" Crl:3COO] Tentative Assignments

1110(s) v4 C104 coordinated

1090(m) v 1 C104 coordinated

1060(w) 1055(w) 1075(w) 1050(m) 1060(w) 1060(w) 1060(w) 1040(m) v2 N03 coordinated

990(m) 980(w) 985(w) 980(w) 985(w) 985(m) 985(w)

950(w) 950(w) 950(w) 950(W) 950(w) 955(w) 950(w) 940(w) v2 CI04 Coordinated

885(w) 880(w) 880(w) 880(w) 880(w) 880(w)

860(m) 860(m) 855(m) 860(m) 860(m) 860(m) 865(w) 825(m) v6 rocking of N03

785(w) 785(w) 770(w) 785(w) 780(w) 780(w) 785(w)

685 690 685 695 685 690 665(m) v3 CI04 coordinated

645(m) v5 CI04 coordinated

550(w) 560(w) 555(w) 555(w) 555(w) 550(w) VM-N

520(w) 520(w) 520(w) 520(w) 525(w) 520(w) 520(w)

470(m) Ncs deformation

470(w) 475(w) 460(w) 465(w) 455(w) 460(w) VM-0

s=strong, vs=very strong, m = medium, b = broad, w = weak, vw = very weak, mb = medium broad and sh = shoulder

Table 5.5 Magnetic susceptibities and magnetic moments of Fe(III), Cr(III) and Mn(III) complexes of DEABCPH2

SI. Complex XMX106

No. cgs.units

1 [Fe(DEABCP)CI] 10851

2 [Fe(DEABCP)Br] 8440

3 [Fe(DEABCP)NCS] 11727

4 [Fe(DEABCP)N03] 10862

5 [Fe(DEABCP)Cl04] 8288

6 [Cr(DEABCP)CI] 5695

7 [Cr(DEABCP)NCS] 5509

8 [Mn(DEABCP)CI] 9976

9 [Mn(DEABCP)Br] 9995

10 [Mn(DEABCP)NCS] 9671

11 [Mn(DEABCP)N03] 8187

12 [Mn(DEABCP)Cl04] 10125

13 [Mn(DEABCP)CH3COO] 9409

XoX106

c.g.s.urnts

149

159

158

143

157

174

182

152

162

161

146

160

184

X'Mx10s

c.g.s. units

11000

8599

11885

11005

8445

5869

5691

10128

10157

9832

8333

10285

9593

XM=Molar susceptibility xo=Diamagnetic correction x'M = corrected Molar susceptibility

µett· At 298K !:3M

5.12

4.53

5.32

5.12

4.49

3.74

3.68

4.91

4.92

4.84

4.46

4.95

4.78

Table 5.6 Absorption bands of Fe(III) complexs of DEABCPH 2

SI. Complex No.

1 [Fe(DEABCP)CI]

2 [Fe(DEABCP)Br]

3 [Fe(DEABCP)NCS]

4 [Fe(DEABCP)N03]

5 [Fe(DEABCP)Cl04]

vw = very weak

Amax nm

380

490(vw)

380

495(vw)

380

490(vw)

380

490(vw)

380

495(vw)

V

cm-1

26,315

20,370(vw)

26,315

20,200(vw)

26,300

20,390(vw)

26,300

20,21 O(vw)

26,315

20, 175(vw)

Assignments

Charge Transfer

6 74 A1g T1g

Charge Transfer

6 74 A1g T1g

Charge Transfer

6 4 A1g

7 T1g

Charge Transfer

6 74 A1g T1g

Charge Transfer

6 4 A1g

7 T1g

•

Table 5.7 Absorption bands of Cr(III) complexs of DEABCPH 2

SI. Complex Amax V Assignments

No. nm cm-1

1 [Cr(DEABCP)CI] 375 26,670 Charge Transfer

461 (w) 21665(w) 4 7 4 A2g T1g

(F)

614(w) 16270(w) 4 7 4 A2g T2

g(F)

2 [Cr(DEABCP)NCS] 375 26,665 Charge Transfer

559(b) 17880(b) 4 74 A2g T 1g

(F)

4 74 A2g T2g(F)

b = broad and w = weak

Table 5.8 Absorption bands of Mn(III) complexs of DEABCPH2

SI. Complex Amax V

No. nm cm· 1

1 [Mn(DEABCP)CI] 360(mb) 27725(mb)

535(b) 18690(b)

2 [Mn(DEABCP)Br] 360(mb) 27770(mb)

534(b) 18700(b)

3 [Mn(DEABCP)NCS] 360(mb) 27750(mb)

535(b) 18690(b)

4 [Mn(DEABCP)N03] 362(mb) 27560(mb)

535(b) 18690(b)

568(sh) 17595(sh)

5 [Mn(DEABCP)Cl04] 360(mb) 27775(mb)

534(b) 1871 O(b)

6 [Mn(DEABCP)CH3COO] 360(mb) 27750(mb)

535(b) 18670(b)

b = broad, mb = medium broad and sh = shoulder

Assignments

Charge Transfer

5 '75 Eg T2g

Charge Transfer sE

g 7 s

T2g

Charge Transfer

5 '75 Eg

T2g

Charge Transfer

5 '75 Eg

T2g

Charge Transfer

5 '75 Eg

T2g

Charge Transfer 5E 7 5T

g 2g

.....

152

Table 5.9 The observed and calculated sin28, (hkl) values and relative intensities of [Fe{DEABCP}CI]

Line No. [hkl] Sin28 observed sin28 calculated Relative intensity 1 (110) 0.0061 0.0067 53 2 (001) 0.0077 0.0073 55 3 (200) 0.0085 0.0092 67 4 ( 111) 0.0153 0.014 53 5 (201) 0.0168 0.0165 42 6 (020) 0.0177 0.0176 44 7 (211) 0.0209 0.0209 42 8 (301) 0.0283 0.028 43 9 (112) 0.0356 0.0359 35

10 (410) 0.04 0.0412 43 11 (401) 0.0447 0.0441 42 12 (302) 0.0497 0.0499 69 13 (500) 0.0576 0.0575 65 14 (322) 0.0667 0.0675 67

15 (103) 0.0684 0.068 74 16 (203) 0.0751 0.0749 53

17 (521) 0.0822 0.0824 90

18 (332) 0.0893 0.0895 82 19 (042) 0.0996 0.0998 42 20 (442) 0.137 0.1366 33

21 (052) 0.1393 0.1392 33

22 (243) 0.1454 0.1456 65

23 (640) 0.1529 0.1534 55

24 (352) 0.1599 0.1599 34 25 (015) 0.1869 0.1869 39

26 (543) 0.1944 0.1938 100

27 (154) 0.2298 0.2291 55 28 (661) 0.2496 0.2485 35

29 (525) 0.2569 0.2576 39

30 (345) 0.2746 0.2738 54

31 (226) 0.2896 0.2896 40

32 (364) 0.2955 0.2959 46 33 (136) 0.3048 0.3047 38

34 (336) 0.3244 0.3231 33

35 (555) 0.3488 0.35 39

a=18.6642A, b=13.4942A and c=10.4764A

153

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