Devanarayanan, S

John, Annamma

Zdravkova, Z

IACS Institutional Repository

Indian J. Phys. 73B (4), 679-684 (] 999) N O T EI J P  Ban international journalV ib r a tio n a l a n a ly s is  o f  N ick el (II) an d  Z in c  (II) co m p lex es  o f  D ie th y l (2 -o x o - l-p h e n y l)  e th y l p h osp h on ateAnnammaJohnSt, John s College, Anchal, Kollam-691 306, Kerala, India S DevanarayananD epartm ent of Physics, University of Kerala, Kariavattom, T hiruvanan thapuram -695  581. K erala, IndiaandZ ZdravkovaFaculty o f Chemistry, Sofia University, 1 J Bourehier Avenue, 1164 Sofia, Bulgaria R e c e i v e d  1 5  M a t c h  7999. a t t e s t e d  2 0  M a v  7999A bstract The FT-IR and FT-Raman spectra of | ( C H , C H , O K  P ( 0 ) C C f H s -  C H - O j ,N i.2H ,() and | ( C H (C H , 0 ) :  P ( O )  C C , H ,  ==CH-(>], Z n \Vj 1 1 , 0  arc recorded and analysed on the basis o f vibiations of benzene ring, ethoxy and ethenc group. P  =  O  bond and P  ( ) - C  bond. It is confirm ed that the zinc complex is a mixture o f (7 ) and (E) isomer while the nickel com plex is (Z)-isom er alone A strong hydrogen bonding is identified between the oxygen atom in P = O and the Hydiogcn atom m the ethenc group in the (E) isomcr of the zinc com plexKeywords FT-IR and FT-Raman spectrum, hydrogen bonding FACS Nos, 31 20 Ha, 33 20 Fb. 33.20.TpSynthesis and characterization of complexes of alkyl phosphonates arc of con^ " * l^ n‘J ,n recent years because of the variety of structural coordination mod* pment intta.ni- Spectroscopic (1R. electronic and EPR) and magnetochemica) studies on cobalt (II). mckcl (1). copper (II) and zinc (ID complexes of diethyl (2-oxo-1 -phenyl) ethyl using the corresponding metal acetates and halides arc reported m the htcratu e l l . - f  S studies reveal that the lithium salt of diethyl (l-methyl-2-oxochyl >mixture of «Z) and (E) forms, while f 1*1 'crilll) complexes"^phosphonate have (Z)-chelate structure [3,4]. The Fe( ) * , • ol thc FT-IRZ,-chelate and (E)-eno.ate forms [5], In thc present work we reportand FT-Ramau speetra or two newly s y n ,Desired p h “  diethoxyphosphonyl-2-phenyl-clhcnolalc) nickel III) D,hydrate. l(CH,CH;Ol, P(O) C ,  ,©19991ACS680 Annamma John, S Devanarayanan and Z Zdravkova==CH-0]2Ni.2H20 , hereafter abbreviated as PN and Bis(2-diethoxyphosphonyl-2-phenyl -  ethenolate) zinc (II). 1 »/2 Hydrate, [(CH3 CH20 )2P(0)CC6 H5 = CH -0]2 Zn. lVtf^O, hereafter abbreviated as PZ.The nickel (II) and zinc (II) complexes were obtained from the corresponding metal halides (NiBr2.3H20  and ZnCl2) and diethyl (2-oxo-1 -phenyl) ethyl phosphonate in the presence of potassium hydroxide. The reaction was carried out at room temperature in CH3 0H/H20  solution. The PN and PZ complexes are obtained as green and white powders, respectively. The FT-IR and FT-Raman spectra of both the samples are recorded using a Bruker IFS 66V FT- IR/FT-Raman Spectrometer. The FT-Raman spectra, over the range 50-3000 cm"1 are recorded using an Nd-YAG laser of wavelength 1064 nm and power 200 mW. The FT-IR spectra are obtained over the range 400-4000 cm '1 with the samples as KBr pellets using globar source.The structural studies of these complexes [2] reveal that PN is octahedrally coordinated by the bidentate phosphonyl ligand, two of the coordination sites being occupied by water molecules. The *H, ,3C and 31P NMR data for the zinc complex prove that the product is a mixture of (Z) and (E)-isomers, with the (Z)-isomer being predominant.The characteristic frequencies observed in the FT-IR and FT-Raman spectra recorded for both the complexes are listed in Table 1. The interpretation of the spectra is done on the basis of characteristic vibrations of phenyl (Ph) and Ethoxy (EtO) groups. Vibrations of P = O, P-O-C, CH of the ethene group, etc are also identified. The EtO group provides 18 normal vibrations, of which 15 are attributed to ethyl and the remaining 3 are attributed to the C-OT able 1. Spectra) data (cm ') and band assignm ents o f [(CH , C H 30 ) ,  P (O) C C ftH s = C H -O J, Ni. 2 H ,0  and [(CH, C H .O ), P (O) C C ,H , = CH -  O], Zn. P/j H , 0 ‘[(C H 3 c h 2o >= C H -O J.2 P (O) c c 6h ,, N i 2H zO[(C H 3 c h 2o >: = CH -  0 ] 2, P (O) C CftH 5 Zn. m  h 2o A ssignm en tsR am an IR R am an 1RP h en y lgroupE th o x y /E th e n egroup M iscellaneous3431 m br 3456 w br v H 20308 5 v w 3085 vw 12 a3 0 5 9 s 305 6 v w 3 0 3 9 s 3056vw 13 0 1 7 v w 301 7 v w 15b vC H2 9 7 9 m 2 9 8 1 m 2 9 7 3 m 2 9 8 2 m V .C H ,2 9 4 3 m 29 2 9 w 2 9 3 0 s 2 9 2 8 m V»CH ,29 0 6 w 29 0 5 w 2 8 9 7 m 2 9 0 5 sh v 4C H 32 8 8 8 v w 2866  vw 2 870w 2 854w v,c h 22 7 6 5 v w 5C H 2 + o)CH22 7 2 4 v w A BandI9 5 5 v w b r B Band2 1 2 9 m 17b + 19a2 1 0 9 m coC H 2 + pC H 22 0 3 3 m 16v +  18a1741vw C Band681Vibrational analysis of Nickel (U) and Zinc (II) complexes etcT a b le  1 ( C a n t ’d )I5 9 4 v s 1 6 0 3 sh 1596 v v s I6 0 3 sh 16a 8H 201 5 5 6 m 1 5 5 1 v v s I5 5 5 sh 1548vvs 16bUIIV14 9 8 v w 1493w 1493vw I493w 13a 6 0  - C H ,1 4 7 3 v v w 1478vw 1476vvw 1476sh28, C H ,1 4 3 3 m 1444w 1445w 1444w 13ba 38C H ,13 9 3 sh 13 9 4 shltoO -  C H 21350w 1359s 1341 w 1365s 5s C H ,1 3 3 2 sh 1335m 91 3 2 0 m 1321 w 1318m coC H 213 00w I3 0 2 w 1296m 312 8 4 w I  C H ,1 2 6 6 m 1 2 5 4 m 1267s 1257m 15a1244s v C -O118 7 v w 1 I8 4 w 17a P C H ,1 1 7 3 m 1 167m vP = O1 158vw 1 156w 17b1082w br 1 102w 1099w 1098w v C -O /v C -C1053s 1052s VaP - 0 - C1 0 3 8 m 1 0 2 5 v s 1305w 1023vslOOOvs 1001 vs 69 7 0 w 9 6 3 s 9 5 5vw 96 5 s 19a8 3 7 v w 821 sh 8 19sh 8CH791 vw 7 9 4  m 790vw 7 9 6 m P C H ,7 7 0 v w 7 5 9 m 761 vw 7 6 1 m 4 v sP ~ O C6 9 7 m 7 0 0 m 693w 7 0 0 m 86 7 1 m 6 6 8 m H20  libration6 2 7 v w b r 6 2 3 v w 62 Iw 620vw 18b5 54w 5 5 1 m 551 vw 5 4 9 m 20b513w 5 I2 w 507 w H ,Q  libration4 8 3 w 4 8 7 v w 476vw 18a M etal-465w O xygen442vw V ibrations426vw4 1 4 w 4 0 9 vw 2 0 a 5 O -C -C397  w 340vw 14b2 7 8 m25 2 w E x te rn a l133m M odes112s8 4 v v s 9 7 v sAbbreviations : w -  weak m -  medium s -  strong v verybr -  broad sh -  shoulder t  -  tw isting v -  stretching(0 -  wagging 8 -  bending p -  rockingSubscript a — asym m etric Subscript s — sym m etric682 Annamma John. 5 Devanarayanan and Z Zdravkovastretching vibration, C -0  deformation and EtO torsion. In monosubstituted benzenes, 6 of the 30 number of normal vibrations are substituent sensitive [6]. The numbering of these modes are done according to Herzberg’s convention [7,8]. However, in the present study, since some of the modes have the same frequency range an unambiguous assignment of certain normal vibrations is not possible.The CH stretching vibrations of the benzene ring usually absorb weakly to moderately between 3120 and 3000 cm"1 [6]. The three weak IR bands at 3085,3056 and 3017 cm”1 in the case of both nickel and zinc compounds may be assigned to the 12a, l and 15b modes. The CH stretching frequency which corresponds to mode 1 is observed with strong intensity at 3059 e n r1 in the Raman spectra of both the compounds. The CH stretching vibration (CH) of the ethene group also appear in this region [9]. The methyl and methylene stretching vibrations namely v ;CHv v,CH2, v CH, and v CH2 are observed in the region between 2982 and 2854 cm '1 (6,10]. These frequencies are such that v CH, > vrtCH2 > vyCH, > vCHrThe ring stretching vibrations 16a, 16b, 13a and 13b arc good group vibrations. When the Benzene ring is substituted by C = C, the 16a and 16b are expected at 1620 -  1585 cm*1 and 1590- 1565 cm"1 respectively [6,1 lj. The very intense Raman band at 1594 and 1596 cm-1 in PN and PZ, respectively are assigned to the 16a mode. The corresponding IR band is observed as shoulder at 1603 cm '1 in both the compounds. The bands of 16b mode arc observed as very intense IR bands at 1551 and 1548 cm '1 and as medium intense Raman bands at 1556 and 1555 cm '1 (shoulder) for PN and PZ, respectively. However, the IR bands of 16b mode is usually weaker than the 16a mode [6, 11 ]. The intensity reversal of these modes of vibration and the shifting of the 16b mode to the lower frequency side may be due to the strong coupling between this mode and the vC = C vibration of the alkene group which occurs in the same region [9]. The bending mode of water also appears in this region.The asymmetric deformation 5CH , is observed at 1478 cm 1 m PN and 1476 cm 1 in PZ and the symmetric deformation 5 CH, is observed around 1350 cm '1. The methyl rock (pCH^) is assigned to the absorption lines at 1187 and 1184 cm '1 in PN and PZ respectively. An ethoxy group on a phosphorous atom absorbs near 1485 (50-CH-,) and 1395 cm"1 (ft)0-CH?) [ 11 ]. In the present study, 50-CH7 mode appears as weak bands at 1493 cm"1 in both the compounds and coO-CH2 as shoulders at 1393 c m 1 (PN) and 1394 cm”1 (PZ).The P-O-C stretching is characterized by a very strong band in the region 1050-970 cm '1 [ 11 - 13]. In most ethoxy phosphorous compounds, this band is a doublet 111). Both the compounds under investigation shows very strong doublets in this region. These are probably due to the asymmetric P-O-C stretching vibration. The medium intense IR bands at 751 cm 1 (PN) and 761 cm"1 (PZ) may be due to the symmetric stretching of P-O-C. Very weak Raman bands are observed in this region. The stretching of the P = O bond gives rise to a strong band at 1300 -  1140 cm-1 [11,14]. Zdravkova et al [2] has assigned the P = O stretching band at 1170 and 1175 cm '1 for the nickel and zinc complexes. In the present investigation, this band is observed as medium intense band at 1173 and 1167 cm '1, respectively, for PN and PZ.A very strong Raman band at 1000 ± 10 cm-1 is a good group frequency characteristic of monosubstituted benzenes [8], This band is due to the in plane trigonal ring deformation (mode 6) in which successive carbon atoms move toward and away from the centre of the hexagon. In the IR, it is usually weak. In the present study, the very intense Raman band at 1000 and 1001 e n r 1 for PN and PZ respectively, are assigned to the mode 6. No IR band is observed for this mode.Vibrational analysis of Nickel (II) and Zinc (II) complexes etc 683The CH out of plane deformation near 770 cm'1 (mode 4) and the out-of-plane ring deformation absorbing near 690 cm-1 (mode 8) form a pair of strong bands characteristic of monosubstituted benzene derivatives [6]. Both these modes appear as medium intense bands in the IR and as weak bands in the Raman. The ring breathing mode 2 of monosubstituted benzenes usually contribute a strong Raman band, whose position is highly substituent sensitive [8, 15]. Its frequency moves in the range 1100-620 cm '1 depending on the mass of the substituent. In the present study, no strong Raman band other than the band around 1 OCX) cm '1 is observed in this region. This may be because of the overlapping of this mode with the in-piane ring deformation mode 6.The substituent sensitive modes 20b, 18a and 14b are assigned around 551,483 and 360 c m '1, respectively [16,17). The weak Raman bands around 625 (mode 18b) and 410cm"1 (mode 20a) are characteristic bands of monosubstituted benzene ring 111]. The metal -  oxygen vibrations shows very weak bands in the region 487-426 cm’1 [ 181. In the case of zinc complex, four bands arc observed in this region which may be due to the presence of metal-oxygen bonds of varying strength. This observation supports the presence of both (Z) and (E)-isomers in the compound as suggested in the structural report (2). The nickel compound shows only one band in this region, indicating that only one structure, namely the (Z)-isomer alone is present in the compound.The broad absorption band at 3431 and 3456 cm’1 for PN and PZ respectively, are due to the stretching vibrations of the water molecules. Librations of water molecules arc observed as medium intense bands around 670 cm"1 and as weak bands around 510 cm '.Combination bands are observed in the range of 2765-2033 cm"1.Strong hydrogen bonded systems are characterised by the appearance of a trio ol very weak broad bands in the region 2800-2400.2350-1900 and 1720-1600 cm"1119]. In the present investigation, the weak and broad bands at 2724, 1955 and 1741 cm"1 in the spectra of PZ suggest the presence of a strong hydrogen bonding in the compound. In the (H)-isomcr of the PZ compound, the hydrogen atom in the ethene group come closer to the oxygen atom ol the P = O bond. Hence, a strong hydrogen bond (O-H-C) may be expected between the two 120] This type of bond formation has a tendency to reduce the energy of P -  O. The red shitt ol i cm"1 in the frequency of the stretching vibrations of P = O bond in PZ when compared to hat in PN confirms the lowering of the P = O bond energy, which is a clear indication of Us participation in a strong hydrogen bonding.AcknowledgmentThank, am due .0 Dr. Dairy Philip. Department of Physic,. Ma, Thiruvananthapuram, India for Ihc valuable suggeslions dnrmg ihc course of tins wo*.R e fe re n c e sII! Z Zdrovkova, I PcU..a, M Mnew. a*  D Mcchaad),.. W " « .  W -  -,21 1 Petrova, D M.chaadha, -  M Mitn.a » « »  *«•" “131 Dtek-1 « “  S i T " ’|4, , Pelrova, Z  Zdrnvko... 1 C Tabby and BTK M  '(5 , 1 Pelrova. Z Zdravkova, O Angelova and I Macieek /  <",r nra. . .

Vibrational Analysis of Nickel (II) and Zinc (II) Complexes of Diethyl (2-oxo-1-Phenyl) Ethyl Phosphonate

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Vibrational Analysis of Nickel (II) and Zinc (II) Complexes of Diethyl (2-oxo-1-Phenyl) Ethyl Phosphonate

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