Synthesis and characterization of copper(II), nickel(II) - NOPR

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a square planar geometry27 . The diamagnetic. [Pci(HBMPxH)2] and [Pd(H2BMPxH)CI2] complexes show absorption band near 23500 cm-1 which may be.
Indian Journal of Chemi stry Vol. 39A, Decembcr2000, pp. 1301-1305

Synthesis and characterization of copper(II), nickel(II), cobalt(II), palladium(II), rhodium(III) and dioxouranium(VI) complexes with biacetylmonoxime phenoxyacetyl hydrazone Sahar I Mostafa*, Tawfik H Rakha & MedhaL M El -Agez Chemi stry Department, Faculty of Sci ence, Mansoura University, Mansoura, Egypt Received 8 March 1999; re vised 27 Seplember 1999

Biacetylmonox ime phenoxyacetyl hydrazo ne (H 2BMPxH) is used in the synthesis of compl exes of the types [Co(HBMPxHM OAc)], [M(H2BMPxH)CI 2] (M = Co(JI), Pd(II)), [Cu(HBMPxH)CI (H20)], [M ' (HBMPxHM H20 )nl (M' = Ni(II), n = 2; M' = Pd(IT) , n = 0), [Rh(HBMPxHMbipy)]CI and [M"(BMPxH)h (M" = Ni(II), Cu(II), UO/+). The isolated complexes have been characterised by elemental analysi s, molar conductivities, magnetic measurements, IR , 11-I NMR and UV -vi sible spectroscopy. The spectral data showed that H2BMFxH function s as neutral bidentate, mononegative bidentate or binegative tridentate li gand .

Biacetylmonoxime phenoxyacetyl hydrazone (H 2BMPxH) is of interest since it has the ability to chelate metal ion through nitrogen and I or oxygen donor centres. The neutron diffraction of dimethyl glyoxime showed the presence of OH bonds with 1.02 A bond length as well as the intramolecular hydrogen bond OH ... ... N with bond length of 2.8 A in the solid 1 state • There are few known transition metal 26 7 complexes containing aromatic · and heterocyclic •8 hydrazone derivatives of biacetylmonoxime. Al so , complexes of biacetylmonoxime Schiff bases have bee n reportedY.Jo. This report describes the preparation and characterisation of some transition metal complexes of biacetylmonoxime phenoxyacetyl hydrazone (H 2BMPxH) on the bases of their IR, 1 H NMR, electronic spectra, magnetic moment and molar conductance measurements.

Materials and Methods Preparation of the ligand Biacetylmonoxime phenoxyacetyl hydrazone (H 2BMPxH) was prepared by refluxing biacetylmonoxime (0.1 mol) and phenoxyacetyl hydrazine (0.1 mol) in I 00 ml ethanol for 2h . The white crystals obtained were filtered, washed and recrystallised from ethanol and dried ove r anhydrous CaCb. Preparation of complexes The [Co(HBMPxHh(OAc)] complex was prepared by refluxing a hot solution of H 2BMPxH (0.002 mol)

and Co(OAc )2.2H 20 (0.00 l mol) in 50 ml ethanol fo r I h. The solid complex was isolated after the additi on of diethylether with scratching. Th e [Co(H 2BMPxH)Cl 2] was produced by the same procedure using equimolar rati o of CoCI 2 and H 2 BMPxH. The complexes [Pd(H 2 BMPxH)Clz] and [Cu(HBMPxH)Cl(H 20)] were isolated by refluxin g H 2BMPxH (0.001 mol) and PdCI 2 or CuCh (0.001 mol) in 50 ml ethanol for 0 .5h and the complexes were obtained after adding doubl y distilled water to the cold reaction mixture. The same method was applied for the isolation of [Pd(HBMPxH ) 2] and [Ni(HBMPxHh(H20hl complexes with 2: I mo lar ratio (H 2BMPxH to metal chloride) follow ed by the addition of 0.5 g of sodium acetate in 30 ml H 20 as a buffering agent. The complex [Rh(HBMPxHh (bipy)]Cl was isolated by refluxing H 2 BMPxH (0.001 mol), 2,2'-bipyridyl (0.001 mol) a nd RhCldH 20 (0.0005 mol) in 50 ml ethanol for 3h when the microcrystalline needles were obtained after coolin g. The dimeric complexes [M(BMPxH)h (M = Ni (II ), Cu(II), UO/+) were prepared by refluxing H 2 BMPxH (0.001 mol) and the corresponding metal acetate (0.00 I mol) in 25 ml ethane,! for 0.5h. In the case o f [Cu(BMPxH)]z, the complex was isolated by usin g aqueous solution of copper acetate. The complexes obtained were filtered, washed with ethanol, ether and dried over anhydrous CaCI 2 • The metal and chloride contents were analysed usin g 11 standard methods • Carbon and hydrogen were determined by the Microanalytical Unit of Mansoura

INDIAN J CHEM, SEC. A, DECEMBER 2000

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Univers ity. Magnetic moments at 25°C were determined using a Johnson Matthey magnetic susceptibility balance and Hg[Co(SCN) 4 ] as calibrant. Electronic spectra in DMF were recorded using Unicam UV2-100 UV-Vis spectrometer. JR spectra were measured as KBr discs on a Matson 5000 FJ'IR 1 spectrometer. H NMR spectra were measured on a Varian Gemini WM-200 spectrometer at National Research Centre, Cairo. Molar conductivities in DMF were measured on Tacussel conductivity bridge CD6NG.

Results and Discussion The analytical data of the complexes are in agreement with their molecular formulae as shown in Table 1. The molar conductivities (1\,11 ) in DMF at 25 °C suggest that [Rh(HBMPxH)2(bipy)]Cl is a 1: 1 electrolyte and the other complexes showed their nonelectrolytic nature. The main vibrational bands (cm- 1) of H 2BMPxH and its complexes are reported. The IR spectrum of the free ligand shows three intense bands at 1692, 1 12 1640 and 1404 cm- assigned to v(C=0) , v(C=N) 13 14 imine and v(C=N) oxime , respectively. The medium intense bands at 1023 and 982 cm- 1 are 10 attributed to v(NO) and v(N-N) stretches. The two 1 bands observed at 3305 and 3207 cm- are probably 13 due to v(N-OH) oxime and v(NH) ; the broad nature of the v(OH) stretching vibration and its wave number suggests the intramolecular hydrogen 15 bonding • Also, the broad weak bands in the regions 1 1960-1800 and 2400-2300 cm- may support the presence of intramolecular hydrogen bonding (OH .. .... N) 3 (Structure 1). 1 The H NMR spectrum of H 2BMPxH in DMSO-d6 shows two singlets at 8 10.0 and 10.75 ppm, which disappeared upon adding D 2 0.-This may be attributed to NH and NOH protons. The noticed downfield shift of these resonances can be related to the amide-imide tautomeric form (HN-C=O) ¢=> (N=C-OH), suggesting the imide formation in solution as well as CIIJ

.

· -o Nii-C-cH 2

"-c =N / CHJ-C

/

~

'

.

11 0

16

the intramolecular hydrogen bonding • The characteristic absorption bands of the free ligand are shifted on complexation and new vibration bands characteristic of complexes appeared, showing that H 2BMPxH behaves in a bidentate and/or tridentate manner depending on the metal salt used, conditions of preparation and the pH of the medium. The IR spectrum of the [Pd(HBMPxHh] complex shows that, H 2BMPxH behaves as a mononegative bidentate ligand coordinating through (C=N) imine and the deprotonated oxime oxygen (NO-). This mode of chelation is expected due to the 10 disappearance of v(OH) stretch , the shift of v(C=N) 2 17 imine to lower wave number ' with the remaining v(C=O) stretch nearly in the same position indicates 2 its non-participation in coordination (Structure II). 1 This view is further supported by the HNMR spectrum of [Pd(HBMPxH) 2] complex , which shows that the resonance arising from NOH oxime proton at 8 10.75 ppm disappears while that at 8 10.0 ppm due to NH proton remains as a singlet nearly in the same 2 position , indicating the trans configuration of the 18 complex • The JR spectra of the complexes; [Ni(HBMPxH)2(H 20) 2], [Co(HBMPxHh(OAc)] , [Cu(HBMPxH)Cl(H20)] and [Rh(HBMPxH) 2(bipy)]Cl exhibit downfield shift of v(C=N) imine with the upfield shift of v(N-N) stretch, disappearance of v(C=O) and v(NH) with the observation of new 1 bands appearing at 1445 and 1225 cm- which may be 3 19 attributed to v(C=N/ and v(C-0) · stretches. The vibration band of v(OH) oxime is shifted to higher wave number due to its non-participation in coordination. These features showed that H 2 BMPxH acts as mononegative bidentate, coordinating to metal ion via (C=N) imine and the deprotonated enolic carbonyl oxygen (=C-0-) centres. TheIR spectrum of [Co(HBMPxH)z(OAc)] shows two extra bands at

-o ~ ~

',H

N-o/

R

-NH-C-CH-0 II

0

~

!2_~

Structure (I)

Structure (II)

Biacctylmonoximc phenoxyacetyl hydrazone (I-I 2 BMPxH)

[Pd(HBMPxHM

MOSTAFA eta/.: Cu(II), Ni(II), Co(II), Pd(Il) , Rh(TII) & UO/+ COMPLEXES

1303

Table !-Characterization data of H2BMPxH and its complexes Complexes (Empi rical Formula), yield(%)

c

Found (Calc.)% H M

B

Dq

!letT

Cl

H2BMPxH (C 12H 15 N30 3 ), 82

57.8 (57.7)

6.1 (6.2)

[Co(HBMPxHMOAc)] (CoC 26 H31 N60 8) , 72 [Ni(HBMPxHMH 20)2l (NiC24H32N60s). 64

50.8 (50.8) 48 .8 (48 .7)

5.1 (5 .0) 5.5 (5.4)

9.6 (9 .6) 9.9 (I 0.1)

[Rh(HBMPxHMbipy)]CI (RhC 34 H38 N80 6), 66

46.0 (45 .9)

4.5 (4.3)

11.6 (11.6)

[Pd(HBMPxHh] (PdC24H2sN6 0 6), 74

47.8 (47.9)

4.7 (4 .5)

17.6 17.4)

lCo(H2BMPxH)CI 2] (CoC 12H, 5CI 2N30 3), 53

38.0 (38.1)

4.0 (4.2)

15 .5 ( 15 .3)

18.7 ( 18.5)

[Pd(H 2BMPxH)CI 2] (PdC 12H 15CI 2NP 3), 65

33.8 (33.7)

3.5 (3.4)

24.9 (24 .7)

16.6 (16.4)

dia

[Cu(HBMPxH)CI(H 20)] (CuC 12 H 16CIN 30 4 ), 68

39.5 (39.3)

4.4 (4.6)

17.4 (17 .2)

7.9 (7.5)

1.94

[Ni(BMPxH)h (Ni2C24H26N606), 50

47.1 (47.0)

4.3 (4.5)

19.2 (19.3)

dia

[Cu(BMPxH)b (Cu2C24H2 6N60 6), 77

46.4 (46.5)

4.2 (4.1)

20.4 (20.6)

dia

[U0 2(BMPxH)h (U2C24H26N60w). 54

27 .9 (27 .9)

2.5 (2.4)

46 .0 (46.0)

dia

ro

1

'

:

o//-~o,yc-cHJ

"'---N Structure (III) [Co(HBMPxHMOAc)].

(o 11

N---L---,-

'"- I

~,.

~ Rb ~

11

v ""'- /

N ----1- - -~ "'--.o

(A)

Structure (IV) A & B isomers of [Rh(I-IBMPxHM Bipy)t. 1

0.49

2214

di a

967

0.93

981

2.9

dia

3.9 (4 .0)

dia 677

0.70

375

4.6

1

/~);?-\ Co

536

1540 and 1440 cm- which may be attributed to Vas(OC-0) and Vs(O-C-0) stretches of acetato group. The

difference between these two bands (100 cm- ) indicates the symmetric bidentate donor behaviour of the acetate 15 as shown in Structure III. The [Ni(HBMPxH)2(H 20)z] and [Cu(HBMPxH)Cl(H20)] show IR bands at 3500, 1605, 890 and 760 cm- 1 assigned to v(OH) , v(H 20), pr(H20) and pw(H 20) stretches of the coordinated water . these mo Iecu Ies, respectt.vc I y 13 ·Is . 0 n drymg complexes upto l20°C, no water molecules are lost indicating their presence in the coordinatior: sphere. 1 The H NMR spectrum of the complex [Rh(HBMPxHh(bipy)]CI shows the formation of two geometrical isomers (A, B; Structure IV) . In the first isomer (A), the methyl resonances are observed at 8 0.90 and 1.75 ppm, whereas for the other isomer (B) at 8 0.94 and 1.65 ppm. Also, only the resonances arising from NOH oximt> proton is observed at 8 10.75, 10.62 ppm for the two isomers while those near 8 10.0 ppm arising from NH proton disappear, indicating the participation of the deprotonated hydroxo-imide oxygen (N=C-0-) and the (C=N) imine in the coordination .

INDIAN J CHEM , SEC. A, DECEMBER 2000

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Structure (V) [Ni(BMPx H)b.

Structure (VI) [[Cu (BMPxH)b

,-. ._ C

~

o-- ------o------N ?! ~~~I . U ~u I '-..__ U I

"""?.

_./"11'-.,__

_./"

o

I

/11"\.

-......__ 1 /

o "\,

N------- 0---- 0

I

I

~ Structure (VII) trans-[ U0 2(BM PxH)h

ln the complexes [M(H 2BMPxH)C I2] (M = Co(Il), Pd(II)) , H2BMPxH behaves as a neu tral bidentate li ga nd coordinatin g Pd(II) throu gh (C=N) imine and th e ox ime oxygen (NO H) centres du e to th e shift of their IR bands to lower wavenumber without affec tin g th e (C=O) stretc h2 . ln th e case of Co(ll) complex, the ligand is coordinat ing via (C=N) imine and (C=N) oxi me centres clue to the shift of v(C=N) imine to lower wavenumber with the sh ift of v(C=N) oxime, v(OH) and v(NO) stretches to higher wavenumber without affecting the v(C=O) stretch es. In the dimeric complexes [M(BMPxH)h (M = Ni(II) , Cu(ll) , U0 22+), H2 BMPxH acts as a bi negative tridentate li gand coordinating metal ion through its (C=N) imine, deproto natecl oxime oxygen(NO-) and the deprotonatecl enolic carbonyl oxygen (=C-0-) centres . This behaviour is supported by the disappearance of v(OH), v(NH) and v(C=O) stretches accompanied by the observation of new bands at - 1545 and 1233 cm- 1 which may be assigned to v(C=N) and v(C-0) 19 stretches, respectively as well as the shift of v(C=N) imine to lo\ver wave number 17.

The 1H NMR spectra of th e complexes [M(BMPxH)h (M = Ni(II), UO/+) support thi s feature clue to the di sappearance of the reso nances ari sing from NOH and NH protons at 8 10.75 and 10.0 ppm . Also, molec ular weight determination supports the dimeric nature of these complexes, H2 BMPxH behaves as a tridentate li gand and one oxygen atom acts as a bridge between th e two metal ions . Structure V- VII show the structures of [M(BMPxH)h (M = Ni(Il), Cu(IT) and UO/+, respecti vely). The complex lU0 2(BMPxH)h shows strong lR band at 925 cm- 1 which may be assig ned to V 0 ,(U0 2) of the trans-O=U=O moiet/ 0 . The observation of new bands near 505 , 395 and 265 cm- 1 in the complexes may probably be assigned to v(M-0)21 , v(M-N) 22 and v(M-CI) 23 , respectively. The magnetic moments, ejectronic sprctra in DMF or DMSO and li gand fie ld parameters of some of the complexes are present in Table I. The electronic spectru m of th e diamagnetic redbro wn [Co(HBMPxHh(OAc)] compl ex exhibits two abso rpti on bands at 20000 and 28570 em-I whi ch may be ass igned to 1A 1g ---7 1T 1g and 1A1g ---7 1T2g transitions, respectivel y in low spin octahedral cobalt (lll) system-'4 . The elec troni. c spectrum of the green [Co(H 2BMPxH)CI2] complex shews a main ba nd at 14925 crn- 1 which may be due to '1A2 ---7 4 T 1(P) transition i.e., v 3 in the tetrahedral fie ld . There is al so a shoulder at 16475 cm- 1 which is attrib uted to spinorbital coupling. Thi s complex is para magneti c wi th magnetic moment va lue 4 .6 B.M . wh ich is normal for tetrahedral Co(ll) com pl. excs25 . The eiectroni c spectrum of [Ni (HBMPxHh( H20 ) 2] complex ex hib its two bands at 16 130 and 277 80 cm- 1 due to 3A 2g ---7 3 T 1g(F) and 3A2g ---7 3T 1g(P) transitions, respectively. The calculated Iiga nd fie ld parameters, v 2/ v 1 ( 1.6) and the magnetic moment va lue (2.90 B.M.) lie within the range reported for octahedral ni ckel (ll) chelates 24'26 . On the other hand, the dimeric diamagneti c [Ni (BM PxH)h complex ex hibits a characteristic absorption band at 19570 cm- 1 wh ich may corres pond to 1A 1g ---7 1A2g transiti on, attributed to a sq uare planar geometry27 . The diamagnetic [Pci(HBMPxH) 2] and [Pd(H2BMPxH)CI 2] complexes show absorption band near 23500 cm- 1 which may be 24 clue to 1A 1g ·-7 1B 1g tran sition in square plan ar (ct system) configuration. The electron ic spectrum of [Rh(HBMPxHh( bipy)]CI ex hibits three bands at 24100 , 19600 and 16950 cm- 1 which may be assigned

MOSTAFA eta/.: Cu(ll), Ni(ll), Co(! I), Pd(ll), Rh(lll) &

to I A lg -> I T2 1:> I A lg -7 ITlg ancliA lg -7 JT lg trans1..t1ons, respectively in an octahedral configuration 18. The dimeric [Cu(BMPxH)h complex is considered to be one of the few Cu(II) complexes in which the spinparamagnetism is quenched completely ()le~r = 0) at room temperature and this may be attributed to metalmetal interaction between the two copper atoms (Structure VI). The electronic spectrum of this complex shows two bands at 16390 and 27030 cm- 1 which may be due to d-d transition and chargetransfer in a square planar geometry around the copper ions. On the other hand, the magnetic moment value ()len 1.94 B.M.) of the complex [Cu(HBMPxH)Cl(H20)], indicates neither spin coupling betwceil unpaired electrons belonging to different copper atoms nor dimeric or polymeric structure. The electronic spectrum shows broad band with a maximum at 14815 cm- 1 which may be due to the combination of 2B 1g -7 2 £ 2x and 2B1g -7 2A1g transition in square planar geometr/ 8 . The electronic spectrum of trans-[U0 2(BMPxH)h complex shows two absorption bands at 22985 and 27400 cm- 1 which is assigned to 1.2:/ -7 2 nu and charge transfer n -7 n*, respectively. References I 2 3 4 5

Barrett A N & Palmer R A, Acta Crystallagr, 23 ( 1969) 688. Bekheit M M, Synth React inorg org-111et Clwn, 21 (1991) 681. Rakha T H, Bekheit M M & EI-Agez M M , Synth React inorg org-111et Che111 , 28 ( 1999) in press. Mostafa M M, Ibrahim K M & Moussa M N H, Tran s 111et Che111, 9 (1984) 243. Mostafa M M, Kattab M A & Ibrahim K M, Polyhedron, 2 (1984) 583.

6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

27

Uo/• COMPLEXES

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Ibrahim K M, El Asmy A A, Bekheit M M & Mostafa M M , Trans 111et Che111, 10 ( 1985) 175. Ibrahim K M, Bekheit M M & Abu El-Reash G M, Tram 111et Che111, 16 ( 1991) 189. Ibrahim K M, Bekheit M M, Abu EI-Reash G M & Mostafa M M, Polyhedron , 5 ( 1986) 1635. Panda A K, Dash A K & Panda M R. Indian J Che111, 35A (1996) 324. Satpathy K C, Panda A K & Panda M R, Trans 111et Ch e111. 16 (1991) 4 10. Vogel A I, Text book of quantitatil'e che111ical analysis 5th Edn(Longmm1 , London) 1989. Castellan G W, Physical che111istry, edited by L Rogers (Benjamin, California) 1983 . Ramadan A M, EI-Mehasseb I M & lssa R M. Tran s 111et Che111, 22 ( 1997) 529. Kahraman A & Irez G , Synth React inorg org-111et Chem , 26 ( 1996) 79 . Nakamoto N, Infrared and Ra111an spectra of inorgan ic and coordination co111pounds, 4th Edn (Wiley, New York ) 1986 . Abu EI-Reash G M, Taha F I, Shallaby A M & EI-Gamal 0 A, Synth Reach inorg org-nzet ChCJn , 20 ( 1990) 887. Ma M S & Angclici R J, ln org ChCJn , 19 ( 1986) 363 . Mostafa S I, Trans 111et Chon , 23 ( 1998) 397. Moszner M, Glowiak T, Kubiak M , Ziolkowski J, Costa G & Tavagnacco C, Polyhedron, 16 (1997) 307. Griftlth W P & Mostafa S M, Polyhedron, II (1992) 2997. Hingorani S, Singh K & Agurwala B V, J Indian che111 Soc, 71 (1994) 183. Bansal S K, Tikku S & Sindhu R S , J Indian che111 Soc, 68 ( !991) 566. Ferraro J R, Low frequency vibration of inorganic anti coordination c0111pound~· (Plenum Press, New York) 1971. Lever A B P, Inorganic electronic spectroscopy 2nd Edn (Elsevier, Amsterdam) 1984. Bekheit M M, Synth React inorg orfi-lll et Che111 , 20 ( 1990) 1273. EI-Asmy A A, Hafez M A, Saad E M & Taha F I, Trans 1net Clze111, 19 ( 1994) 603. Singh S, Yadava B P & Agarwala R C, Indiwz J Che111, 23A ( 1984) 441.