Download IJCA 40A(6) 652-655

Indi an Journal of Chemistry
Vol 40A June 200 I, pp 652-655
Synthesis and characterization of some novel
6
mixed-ligand cyanonitrosyl {MnNO}
complexes of manganese(!) involving
multifunctional bioactive organic donors
R C Maurya * & S Batalia
Coordination Chemistry Laboratory, Department of P G Studies
& Research in Chemistry,
R D Unive rsity, Jabalpur 482 00 I, Indi a
Received II September 2000: revised 12 Ma rch 2001
Novel mixed-l igand cyanonitrosyl complexes of manganese( l),
formed by interaction of pentacyanoni trosylmanganate(l) anion,
[Mn(NO)(CN)] 3-. wi th 2,3-pyridincdiearboxylic acid (PDA),
7-ch loro-4-(3-di ethylami nomct hyl-4-hydrox yan iIino )qui no!ine dihydrochloride dih ydrate (C DAHQ) and 4,4'-diami nodiphenyl
su lphone (DADPS), have been synthesized and characteri zed by
eleme ntal analyses, molar conductances, mag netic and
decomposition temperature measurements, in frared and electronic
spectral studies. The compl exes have the compositi ons .
[Mn (NO)(CN)o(PDA)>(H
O)].Mn(NO)(CN),(CDAHQ)(H
,O),)
and
2
[Mn (N O)(CN)z( DADPS)(H20)b- Suitab le octahedral structures
have been proposed for these complexes.
Although in recent years there has been great interest
in the synthe sis and characterization of neutral mixed5
liga nd cyanonitrosyllisoth iocyanatonitrosyl {CrNO )
complexes of Cr(I) involvin g bioactive molecul es,
1
there is a single re port on mi xed-li gand nitrosyl
6
compl exes of {MnNO} complexes of manganese(!)
with bioactive organic donors. It was, therefore,
thought of interest to synthesize and characterize
6
some cyanonitrosyl
{MnNO}
complexes of
manganese(!) with multifunctional bioacti ve organic
donors , viz., 2, 3-pyridinedicarboxylic acid (PDA),
7 -chloro-4-(3-diethy laminomethyl-4-hydrox yan iIi no)quinoline dihydrochloride dihydrate (CDAHQ) and
4,4'-diaminodiphenyl sulfone (DADPS). PDA is
2
metabolite of tryptophan. Sch warcz has reported its
ne uroexcitatory acttvtty and possible role in
neurodegenerative disorders. CDAHQ is well known
antimalarial drug 3 . DADPS is reported to be a
leprostatic drug 3 . As the biological activity is often
4
augmented when the ligand forms complexes with
metal ions, the res ulting mixed-ligand complexes may
be of potenti al biological importance.
Experimental
Potassium cyanide (M & B C he micals, Bombay),
(Robert
Johnson ,
hydroxyl ammoniumchloride
Bombay), potass ium hydroxide and KMn0 4 (BDH),
2,3-pyridinedicarboxylic acid (Aldri c h Chemic al Co.
USA), CDAHQ (obta ined as g ift sa mple from JDPL,
Hyderabad) and 4,4'-diaminodiphe yl sulfone (Sigma
Chemical Co., U.S.A.), were used as supplied. The
parent anion, pentacya nonitrosylmanga nate (I), [Mn
(NO) (CN) 5 ] 3-, was prepared by foll ow ing the
5
procedure of Bhattac harya et al.
Synthesis of th e complexes
To a red-purple solution of the parent anion ,
[Mn(NO)(CN)s] 3- (obtained by th e procedure of
Bhattac harya et a/. ), an aqueous acetic acid sol ution
(7-10 mL, 1:1 ) of PDA (1.057 g), C DAHQ (1.474 g)
or DADPS (0.785 g) was added with shaking. The
resultin g so luti on was reflu xed [2h; PDA : 3h;
CDAHQ: 45 min ; DADPS], w hen a coloured so lid
was prec ipitated. The resulting precipitate was
filtered by suction, washed several cimes with dilute
acetic acid, finally with water and dried in vacuo at
room temperature to a constant weight. Yi eld : 4052% .
Carbon, hydrogen and nitrogen we re determined
by microanalys is at CDRI, Luckn ow . Manganese was
determined grav imetricall / as MnNH4P0 4.H20 .
Conductance meas urements were performed at
room temperature 1t1 ethanol using Toshniwal
conductivity bridge and dip-type cell with a smooth
platinum e lectrode. Solid-state infra red spectra of the
ligands and complexes were recorded on a Ff 1R
spectrophotometer in Nujol mulls in the range 4000500 cm- 1• Electronic spectra of the compl exes were
recorded in 10· 3 M solutions in ethanol on a
Shimadzu, model UV -160 spectrophotometer. The
magnetic susceptibility was meas ured at room
temperature on a Gouy balance usi ng Hg[Co(NCS)4]
as calibrant, at Central Salt and Marine Chemical
Research
Institute,
Bhavnagar.
Decomposition
temperatures of compounds were determined using an
electrothermal apparatus having capacity to record
temperatures upto 360°C.
NOTES
Analytical data and important lR spectral bands (cm-1) of the com plexes
Table 1Sl.
Compound
Found (Ca lc.), %
c
H
N
39 .1 0
(39.26)
2.21
(2.45)
14.58
( 14.31)
4.42
(4.65)
13.68
( 13 .96)
3.22
(3 .47)
17.65
( 17 .36)
No. (Empirical Formula, M ol. Wt.)
I.
[Mn (N0)(CN )2(PDA )2(Hz0 ))
(C, 6H 12Ns010Mn, 489)
2.
[Mn (NO)(CN)2(CDAHQ) (H zOh J 43 .62
(43 .89)
(C22H2sN60• Cl]M n. 60 1.5)
3.
[Mn (NQ)(CN)2(DADPS) (1-hO)h
(CzsHzsN100s S2Mn 2, 806)
41.78
(41.68)
S!C l
v(NOt
v (C=N) v(M nNO)
2142
17 .39
( 17.70)
9.68
(9 .14)
1840
211 1
2 144
7.72
(7 .94)
13.39
( 13.64)
1800
2109
2 140
CH3COOH
[Mn(NO)(CNh
H20
(PDAh (H20)] +3HCN + CH3COOCH3COOH
1Mn(NO)(CN) 5] 3-+CDAHQ - ---+
Hp
[Mn(NO)(CNh(CDAHQ)(H 20) 2]+3HCN+ CH 3COO
CH3COOH
2[M n(NO)(CN) 5] 3-+2DADPS
H20
[M n(NO)(CNh(DADPS)(H 20)h+6HCN +6CH 3COO
The partial rep lacement of the cyano groups in the
parent an ion, [Mn (NO) (CN) 5 ] 3- by two molecu les of
PDA , or one molecule of DADPS or CDAHQ is
fac ilitated due to the trans directing effec t of the
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nitrosy l group, as observed by Maurya et al. in the
interac tion of pentacyanonitrosylchromate(l) ani on
with different bio log ically ac tive organic donors.
The ana lytical data of these synthesized complexes
are g iven in Table 1. The res ulting compounds
synthes ized in thi s investigation are non-hygroscopic
and air-stable coloured so lids. They are thermally
stable and the ir thermal decomposition temperatures
are: [Mn(NO)(CNh(PDAh(H20)] (>250°C); fMn (NO)
(CN h (CDAHQ) (H20 h ] (>250°C);[Mn (NO)
(CNh(DADPS) (H20 )h (80- 120°C). These compounds
are moderately so lub le in ethanol , methano l and
dimethylformamide but insolubl e in water. All the
compo und s, after decomposi ti o n with KOH , fol lowed
by acid ifying with acetic acid , g ive a pink colour with
8
a few drops of Griess reagent . Thi s test show s the
7
presence of NO+ groupin g in these complexes. The
res ultin g complexes were charac te ri zed on the bas is
of following ph ys ica l studi es.
v (OH) Pyridin e
ring
Breathin g
mode
17 88
The mixed -li ga nd complexes reported here, were
prepared according to the follow ing equations:
v(C=N)
Mn
11 .42
( 11.24)
Results and discussion
[M n(NO)(CN) 5 ] 3-+2PDA
653
2 11 0
62 1
1601
3528
1086
665
1609
3238
3550
3400
1033
543
1600
3580
3460
The mol ar conductances of these complexes in
3
10- M ethanol solution are in the range 2.8-7.0
1
2
1
ohm- cm mor • These values are indicative of the
9
non-el ectrolytic nature of these complexes. The
magnetic susceptibility meas ure ments of these
complexes indicate that they are di amagnetic and
hence they should have a ground state with a
2
10
(2e)\ 1b2) . Thi s
mo lec ul ar orbital configuration
6
result is consistent with a low-spin {MnN0} e lec tron
10
configuration of manganese(!) in these complexes.
The diamagnetic and non-e lec trol ytic nature of these
complexes a lso supports the presence of NO+
grouping in these complexes.
The electronic spectra of two compound s (1 and 3)
are recorded in 10- 3 M DMF so luti ons. They ex hi bit
three characteristic absorpti on peaks at 285-295 , 360370 and 450-430 nm. The e lectronic trans itions
responsible for these c haracteristic UV -vis . peaks in
the compounds are like ly to be 1b2 ------? 4a 1, 1b 2
----?1b 1 and lb 2 ----?3e, res pec ti ve ly, considering an
MO
diagram
applicable
to
hexa-coordin ate
0
mononitrosy l comp lexes of C4 v sy mmetr/ . These
observation s are comparable to the resu lts reported
5
elsew here .
The important infrared spectra l bands for the three
synthes ized complexes under stud y are presented in
1
Table 1. The very strong band at 1788- 1840 cm- , a
strong band at 2 140-2 144 cm-1 wi th a shoulder band
at 2109-2111 cm- 1 and a weak band at 543-663 cm-1
are assigned to v(NOt, v(CN) and v(M nNO),
This is in agreement with results
respective ly .
1
reported e lsewhere 5· 1,1 2 . The appeara nce of a broad
1
band at 3528-3238 c m- in all the comp lexes due to
v(OH) suggest the presence of coordinated water
molecule(s) in these complexes. For the sake of
convenience, the remainin g interpretation is divided
into three parts :
INDIAN J CHEM, SEC. A, JUNE 2001
654
(2)
(3)
PDA complex
The heterocyclic base PDA used in the present
investigation contains three functional groups: (i) and
(ii) the carboxyl oxygens (iii ) the ring nitrogen. The
v(COO) mode appearing at 1670 em·' in the free
ligand remains unchanged (seems to be merged with
vNO+ mode) after complexation. This suggests that
the carboxyl oxygens of the ligand under study are
not taking part in coordination. Coordination through
the pyridine ring nitrogen causes an increase in the
13
v(C=N) and ring breathing modes • The appearance
of v(C=N) and ring breathing modes due to the ring
nitrogen in the complex under study at 1601 and 1086
em·', respectively, (as compared to that of the free
ligand at 1590 and 994 em·', respectively) is
indicative of the coordination of this ligand through
the ring nitrogen atom.
DADPS complex
The present ligand under discussion contains four
potential functional groups: (i) and (ii) the amino
nitrogens, (iii) and (iv) the sulphone group oxygens.
The appearance of v(S=O) mode in the complex
around the same frequency as that of the free ligand
indicates the inertness of sulfone group oxygen in
bonding. The Vas(N-H) and V5 (N-H) bands which
occur at 3450 and 3350 em·' in the free ligand
undergo a low energy shift and appears at 3330 and
3230 em·', respectively, after complexation . Th is
observation suggests the coordin a;:ion of both th e
to manganese.
amino nitrogen of DADPS
Considering the far apart p-amin o nitrogen in the
ligand, the formation of a binuclear complex is
expected. This is because coordination of both the
amino nitrogens to the same metal centre in a
mononuclear complex is quite diffi cult. Such a result
is reported by Maurya et al. 1'1 in a dimeric
dioxomolybdenum(VI) complex, w herein a Schiff
base ligand derived from benzid ine acted as a
bridging bidentate ligand between two molybdenum
centres.
CDAHQ complexes
The ligand CDAHQ under study contains three
potential functional groups: (i) the quinoline ri ng
nitrogen (ii) the secondary amino nitrogen (i ii) the
tertiary amino nitrogen. A comparison of the infrared
spectral bands of the free ligand and its complex
2
shows that the sp v(C-N) and sp 3v(C-N ) for
secondary and tertiary amino groups, respectively,
undergo no significant changes. T he se observations
suggest that the secondary and tertiary amino nitrogen
of the ligand CDAHQ are not in vol ved in bonding.
However, the evidence of coordination of the
quinoline ring nitrogen is manifested by the
significant shift to higher wave numbers of the ring
13
v(C=N) and ring breathing modes of the free ligand
occurring at 1590 and 990 em·', respectively (see
Table 1). These observations sugges t the unidentate
coordination of the ligand CDAHQ to manganese.
Such a result is expected because of the presence of
two amino groups far apart from the ring nitrogen in
the ligand. The possibility of this ligand to function as
a bridging bidentate between the two metal centres in
a dimer, is ruled out, because of the steric demands of
the ligand.
The satisfactory analytical data and physical
studies presented above suggest that the complexes
understudy are of the compositions, [Mn (NO)
(CNh(PDAh(H 20)] ,Mn NO)(CN)2(CDAHQ)(Hz0 h ]
and [Mn (NO) (CNh(DADPS) (H20)]z. Considering
the structures of the first and third aquated species of
pentacyanonitrosylchromate(l) anion {similar to
pentacyanonitrosylmanganate(l) anion} used as a
parent compound in the present investigation
NOTES
15
reported by Raynor and co-workers ; it is reasonable
to propose, for the analogues manganese complexes,
the octahedral structures, monomeric for compounds
1 and 2, and dimeric for compound 3 as shown in Fig.
Acknowledgement
Financial assi stance from the UGC, is gratefully
acknowledged . The authors are thankful to Prof. M C
Agrawal , Head , Dept. of Chemistry, for providing
laboratory facilities and helpful discussion and to
Prof. S. Sharma, Vice-Chancellor, R D University, for
encouragement.
References
I Maurya R C & Verma R, Indian J Chem, 37A (1998) 147.
2 Schwarcz R, Science, 219 ( 1983) 316.
3 The Merck Index, An encyclopedia of chemicals drugs and
biolog icals, lOth Edn (Merck and Co. Inc, Rah way, N1 ,
USA ) 1983 .
4 Ti an 1 L, Gao E Q, Liand Y T & Liu S X, Synth react inorg
met-org chem, 25 (1995) 417 .
655
5 Bhattacharya R, Ghosh N & Bhattacharjee G P, J chem Soc
Dalton Tran s, ( 1989) 1963 .
6 Vogel A I, A text book of quantitative inorganic analysis
including elementary instrumental analysis, 4th Edn. (ELBS
and Longman, London ), 1979 470.
7 (a) Maurya R C, Shukl a R, An and am N & Shri vastava S K,
Tran met Chem, 12 ( 1987) 203.(b) Maurya R C, Mi shra D
D, Awasthi S & Mukherjee S, Synth react inorg met-org
chem, 21 , 1447 (1991 ).
8 Gri ess P, Chem Ber, 12 (1979 ) 427.
9 Geary W 1, Coo rd. clu m Rev, 7 ( 1971 ) 82.
I 0 Enemark 1 H & Feltham R D, Coord chem Rev, 13, 339
( 1974).
II Ferraro 1 R, Low-frequency vibrations of inorganic and
coordination compounds (Plenum Press, New York,) 1977, 240.
12 Nakamoto K, Infrared and Raman spectra of inorganic and
coordination compounds, 3rd Edn (John Wiley, New York)
1978, 296, 259 .
13 Zaidi SA A, Kh an T K & Neelama N S, In dian J Chem, 19A
( 1980) 169.
14 Maurya R C, Mishra D D, 1aiswal M N & Rao N S,
Polyhedron, 12 ( 1993) 2045.
15 Burgess 1, Goodman B A & Raynor 1 B, J chem Soc, A
( 1968) 50 I.