Synthesis & IR Spectral Studies of Some Metal Chelates of 3-Nitrosoformazans K. C. KALlA*, ANIL KUMAR & JIWAN MALHOTRA Department of Chemistry, Punjabi University, Patiala Received 26 October 1978; accepted 9 July 1979 3-Nitrosoformazans (la-c) form metal chelates (!Va-i) with -Ni(II). CUlII) and Co(II or ill). The IR spectra of these chelates .are very different from those of the ligands. The chelates appear- -to have a nitronic type of linkage as indicated by the disappearance of the frequency of nitroso group and the appearance of a new intense and broad absorption around 1200-1300 cm-l. The oxime .aniont Hl) of 3-nitrosoformazans{I) also reacts with these metal ions to give chelates identical with IV. The IR spectra of IV are similar to those of the corresponding metal chelates (IX) of .arylazooximes showing similarity in their structures. NITROSOFORMAZANS of the type (I) act as strong chelating agents and readily react with metal ions like Ni 2 +, Cu 2 + and C03+ etc. to form well-defined brown to black crystalline compounds. The synthesis and IR studies of some of these metal complexes are reported in this note. The ligands (la-c) were prepared by the controlled reduction of 3-nitroformazans (IIa-c) with H 2 S in -ethanolic ammoniacal solutions at low temperature'. Bis (3-nitroso-l, 5-diphenylJormazan)Ni(II) (IVa)- It was prepared by reacting a methanolic solution of Ia with aq. methanolic solution of Ni(II) acetate. The resulting solution was refluxed for 2 hr, and the brownish black precipitate formed was crystallized -from chloroform-hexane to give IVa. Bis(3-nitroso- 1,5-di-p-tolylformazan)Ni(II)(IVb) and bis (3-nitroso- 1,5-di-o-tolylformazan)Ni(Il)(IVc) were also prepared -in a similar manner. Nickel was estimated by oxidising a known amount of the complex with a mixture of cone. HN0 3 , cone. H 2 S0 4 and HCI0 4 and dissolving the residue in dis- tilled water. Ni was estimated as Ni(DMG)2 in the .above solution. Bis (3-nitroso - 1, 5-diphenylJormazan)Cu(Il)( IVd)- An aq. solution of excess Cu(II) acetate tetrahydrate was added slowly to the methanolic solution of Ia. The resulting solution was refiuxed for 1 hr and the reddish brown precipitate filtered and crystallized from chloroform-hexane to give IVd. Bis (3-nitroso-l, 5-di-p-tolylformazan)Cu(II) (IVe) and bis (3-nitroso-l, 5-di-o-tolylformazan(Cu)(II) (IVf) were also prepared in a similar manner. The organic matter of a known amount of complex was oxidised with cone. HN0 3 , ·conc. H 2 S0 4 and HCI0 4 mixture and the residue dissolved in distilled water. Copper was estimated gravimetrically" in this solution. Tris(3-nitroso-l, 5-diphenylJormazan)Co(III) (IVg) - An aq. solution of excess hexammine ·cobalt(IIl) chloride was mixed with a solution of Ia in acetone or methanol at room temperature, refiuxed -for 1 hr and the violet coloured precipitate filtered .and crystallized from chloroform-hexane to give IVg. Tris(3-nitroso-l 5-di-p-tolylformazan)Co(III) ';(IVh) and tris(3-nitroso-l, 5-di-o-tolylformazan)Co (lID (IVi) were also prepared in a similar manner. -- Alternatively, the complex IVh could be prepared ,. NOTES (11) /Ar N=N (+1(_) / KON-c "N=N Q I 9 '-.....Ar c,Ar - C6HS: M. N'i : n _ 2 b. Ar - CeH4CH3(P-)!M- Ni; ",.l c. Ar. C6H4CH3(O-l,M•.NI; n. 2 d. Ar. C 6 H S ,M.Cu. 0.2 e, Ar. CeH 4 CHjP-"t,.1. Cu; 0.2 f I Ar· C6HaCH3'O-);M-Cuj n.2 g. A r. C6H5: M • Co, T> • 3 h. Ar. C6Ha CH 3 (P-); Ms Co; n. 3 I. Ar - C 6 H4 CH 3 (O-l;Mc. Co ~n. 3- I Ar N-N f '\... ON-C /' M/o 2 "W" (VIII) ~ N .•.•...• Ar 1-lilondV-VIl a, Ar • C6H.5 b , Ar = C 6 H 4 CHjP-' c, Ar - C 6 H a CHjO-J TABLE 1- FHYSICAL DATA OF THE METAL COMPLEXES OF 3-NITROSOFORMAZANS Metal Mol. formula m.p, complex °C* N(%)t . M(%) , Found Calc. Found Calc. IVa C••H2oNlo02Ni 240 24.80 24.86 1036 10-42 IYb C 30 H. s N loO.Ni 215 22,51 22.62 932 9-48 IVc C30H2SNloO.Ni 238 22.51 22.62 9.34 9-48 IYd C26H.oN lOO.CU 213 24.50 24.65 11.00 11.18 IVe C30H2SN,002CU 180 2231 22-44 10.00 10.18 IYf C30H. s N,002CU 190 22,29 22..44 10.04 10.18 IVg C••H 30 Nj.0 3 Co 170 26.80 25.76 7.10 7.22 IVh C4.H42N ,.03CO 163 n18 23.34 6-46 6.55 IVht C4.H42N,.03CO 1635 23.20 2334 6-42 6.55 IVi C4.H4.N l.03CO 190 n12 2334 6.38 6.55 *The melting points reported are uncorrected. +All the metal complexes gave satisfactory analyses for C and H. tPrepared from Co(ll) acetate. by taking aq.· Co(Il) acetate instead of hexammine Co(IlI) chloride. Cobalt was estimated by a new reagent phenylazoacetaldoxime''. The melting points and microanalytical data of all the above complexes are given in Table 1. 3-Nitrosoformazans (la-c) are green coloured compounds showing .\max at 630 nm in benzene. Their IR spectra exhibit bands at ,.....1500-1520 (vN=O), 1120-1150(vCN of C-N=O)4 and 2900 -3200 cm? (vNH) indicating that they are strongly conjugated, intramolecularly hydrogen bonded mono- meric nitroso compounds'. Their pmr spectra in CDCI 3 show them to have a symmetrical structure of the type 1'. Addition of a little alkali to the solution of I converts it completely to the corresponding azooxime anion (III) which is yellow in colour and exhibits typical azo absorptions, However.in metha- nol it shows no absorption at 630 nm. The IR spect- rum of III also shows the disappearance of vNH and. 525
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Synthesis & IR Spectral Studies of Some MetalChelates of 3-Nitrosoformazans
K. C. KALlA*, ANIL KUMAR & JIWAN MALHOTRA
Department of Chemistry, Punjabi University, Patiala
Received 26 October 1978; accepted 9 July 1979
3-Nitrosoformazans (la-c) form metal chelates (!Va-i) with-Ni(II). CUlII) and Co(II or ill). The IR spectra of these chelates.are very different from those of the ligands. The chelates appear--to have a nitronic type of linkage as indicated by the disappearanceof the frequency of nitroso group and the appearance of a newintense and broad absorption around 1200-1300 cm-l. The oxime.aniont Hl) of 3-nitrosoformazans{I) also reacts with these metalions to give chelates identical with IV. The IR spectra of IVare similar to those of the corresponding metal chelates (IX) of
.arylazooximes showing similarity in their structures.
NITROSOFORMAZANS of the type (I) act asstrong chelating agents and readily react with
metal ions like Ni2+, Cu2+ and C03+ etc. to formwell-defined brown to black crystalline compounds.The synthesis and IR studies of some of these metalcomplexes are reported in this note.
The ligands (la-c) were prepared by the controlledreduction of 3-nitroformazans (IIa-c) with H2S in-ethanolic ammoniacal solutions at low temperature'.
Bis (3-nitroso-l, 5-diphenylJormazan)Ni(II) (IVa)-It was prepared by reacting a methanolic solution ofIa with aq. methanolic solution of Ni(II) acetate. Theresulting solution was refluxed for 2 hr, and thebrownish black precipitate formed was crystallized-from chloroform-hexane to give IVa. Bis(3-nitroso-1,5-di-p-tolylformazan)Ni(II)(IVb) and bis (3-nitroso-1,5-di-o-tolylformazan)Ni(Il)(IVc) were also prepared-in a similar manner.
Nickel was estimated by oxidising a known amountof the complex with a mixture of cone. HN03, cone.H2S04 and HCI04 and dissolving the residue in dis-tilled water. Ni was estimated as Ni(DMG)2 in the.above solution.
Bis (3-nitroso - 1,5-diphenylJormazan)Cu(Il)( IVd)-An aq. solution of excess Cu(II) acetate tetrahydratewas added slowly to the methanolic solution of Ia.The resulting solution was refiuxed for 1 hr and thereddish brown precipitate filtered and crystallizedfrom chloroform-hexane to give IVd. Bis (3-nitroso-l,5-di-p-tolylformazan)Cu(II) (IVe) and bis (3-nitroso-l,5-di-o-tolylformazan(Cu)(II) (IVf) were also preparedin a similar manner. The organic matter of a knownamount of complex was oxidised with cone. HN03,
·conc. H2S04 and HCI04 mixture and the residuedissolved in distilled water. Copper was estimatedgravimetrically" in this solution.
Tris(3-nitroso-l, 5-diphenylJormazan)Co(III) (IVg)- An aq. solution of excess hexammine·cobalt(IIl) chloride was mixed with a solution of Iain acetone or methanol at room temperature, refiuxed-for 1 hr and the violet coloured precipitate filtered.and crystallized from chloroform-hexane to giveIVg. Tris(3-nitroso-l 5-di-p-tolylformazan)Co(III)
';(IVh) and tris(3-nitroso-l, 5-di-o-tolylformazan)Co(lID (IVi) were also prepared in a similar manner. --
Alternatively, the complex IVh could be prepared
,.
I
(
NOTES
(11)/Ar
N=N(+1(_) /
KON-c
"N=NQI9 '-.....Ar
c , Ar - C6HS: M. N'i : n _ 2b. Ar - CeH4CH3(P-)!M- Ni; ",.lc. Ar. C6H4CH3(O-l,M•.NI; n. 2d. Ar. C6HS,M.Cu. 0.2e , Ar. CeH4CHjP-"t,.1. Cu; 0.2f I Ar· C6HaCH3'O-);M-Cuj n.2g. A r. C6H5: M • Co, T> • 3h. Ar. C6Ha CH3(P-); Ms Co; n. 3I. Ar - C6H4 CH3(O-l;Mc. Co ~n. 3-
IAr
N-Nf '\...ON-C /' M/o2 "W"
(VIII) ~N .•.•...•Ar1-lilondV-VIl a, Ar • C6H.5
b , Ar = C6H4CHjP-'
c , Ar - C6HaCHjO-J
TABLE 1- FHYSICAL DATA OF THE METAL COMPLEXES OF3-NITROSOFORMAZANS
Metal Mol. formula m.p,complex °C*
N(%)t . M(%) ,
Found Calc. Found Calc.
IVa C••H2oNlo02Ni 240 24.80 24.86 1036 10-42IYb C30H.sN loO.Ni 215 22,51 22.62 932 9-48IVc C30H2SNloO.Ni 238 22.51 22.62 9.34 9-48IYd C26H.oN lOO.CU 213 24.50 24.65 11.00 11.18IVe C30H2SN,002CU 180 2231 22-44 10.00 10.18IYf C30H.sN,002CU 190 22,29 22..44 10.04 10.18IVg C••H30Nj.03Co 170 26.80 25.76 7.10 7.22IVh C4.H42N ,.03CO 163 n18 23.34 6-46 6.55IVht C4.H42N,.03CO 1635 23.20 2334 6-42 6.55IVi C4.H4.N l.03CO 190 n12 2334 6.38 6.55
*The melting points reported are uncorrected.+All the metal complexes gave satisfactory analyses for
C and H.tPrepared from Co(ll) acetate.
by taking aq.· Co(Il) acetate instead of hexammineCo(IlI) chloride. Cobalt was estimated by a newreagent phenylazoacetaldoxime''.
The melting points and microanalytical data of allthe above complexes are given in Table 1.
3-Nitrosoformazans (la-c) are green colouredcompounds showing .\max at 630 nm in benzene.Their IR spectra exhibit bands at ,.....1500-1520(vN=O), 1120-1150(vCN of C-N=O)4 and 2900-3200 cm? (vNH) indicating that they are stronglyconjugated, intramolecularly hydrogen bonded mono-meric nitroso compounds'. Their pmr spectra inCDCI3 show them to have a symmetrical structure ofthe type 1'. Addition of a little alkali to the solutionof I converts it completely to the correspondingazooxime anion (III) which is yellow in colour andexhibits typical azo absorptions, However.in metha-nol it shows no absorption at 630 nm. The IR spect-rum of III also shows the disappearance of vNH and.
525
INDIAN J. CHEM., VOL. 18A, DECEMBER 1979
(-)(+)appearance of "NO of C=N- 0 K at 1120 cnr '(ref. 1).
The Ni(II) and Cu(II) chelates (IVa-f) are deepbrown whereas Co(III) chelates (IVg-i) are violet incolour and can be prepared either from Co(III) orCo(II) salts. The Co(II) solution is easily oxidisedto Co(III) in the presence of the ligands (la-c) as hasbeen observed in the preparation of Co(III) chelatesof arylazooximes-.
3-Nitrosoformazans(I) have many coordinatingcentres. If these ligands act as bidentate chelatingagents, structures of the types IV, V, VI and VII arepossible for their metal chelates. The present investi-gations are in favour of IV due to the followingreasons.
(i) The IR spectra of the chelates are very differentfrom those of ligands, The basic structural featuresof V, VI and VII are essentially the same as those of1. In case V, VI and VII were the correct structures,one should have expected similar IR spectra for themetal chelates and the ligands(I) with slight variationsin "N=N (in V and VI) and "N=O (in VII) alongwith the disappearance of '1NH of the ligands. Forexample, the IR of 3-nitroformazans (Ila-c) and theirmetal chelates VIII (N02 group does not take partin coordination) are very similar with no majorchange in the intensity or position of "N02 and otherother important frequencies".
But, in the IR of the metal chelates of 3-nitroso-formazans (la-c) the broad and strong "N=O and"C-N of C-N=O appearing in the ligands around1500-1520 and 1100-1150 cnr ' respectively, disap-pear. However; vN=N and"C=N bands are observedaround 1420-1430 (ref. 5) and 1640-1660 cnr?respectively both in the ligands (la-c) and their metalchelates. A very intense and broad absorptioncharacteristic of nitronic linkage appears in the IRof metal chelates between 1200 and 1320 cnr '. Thisband is absent in the IR of 1. This absorption alsoappears in many other dimeric nitroso compoundscontaining N -+ 0 linkage. Thus, the IR of metalchelates of I can best be explained by assuming IVto be the correct structure for the metal chelates.
(ii) If IV is the correct structure, it should showIR spectra similar to those of the correspondingmetal chelates (IX) of arylazooximes; the two struc-tures are similar except for an additional azo groupin IV. A comparison of the IR of IV and IX of thesame metal ion shows them to be very similar.
(iii) The oxime anions (IlIa-c) react with Ni(II),Cu(II) and Co(III) salts to form metal chelates identi-cal with IVa-i as confirmed by their spectroscopicand microanalytical data. It is now a well knownfact that oximes react with metal ions through nitro-gen? to form complexes containing N -+ 0 type oflinkages6's-H. Thus, "NO of the simple oximesappears between 900 and 1050 cm-1 which shows anupward shift on chelation of the oximes with metalto 1200-1350 cm'". The "NO in the oxime anionIlIa or IIIb also shows an upward shift from 1120to 1200-1320 em= on chelation with the metal ions,confirming the presence of nitronic linkage. Themonomeric nitroso compounds are labile and have atendency to get converted into the oxime15•16• It there-
526
/
I
fore, appears from the above evidences that thenitroso ligands probably react with metal ions in theoxime form to give metal chelates of the type IV.
Thanks are' due to the CSIR, New Delhi for theaward of a senior and a junior research fellowshipsto A.K. and J.M .• respectively.
References1, KALlA, K. c., KUMAR, A. & MALHOTRA,J., Indian J.
Chern. (communicated)- 2. KALlA, K. C, & KUMAR,A., Indian J. Chem., 14A (1976),
545.3. VOGEL,A. I., A text book of quantitative inorganic analysis
(Longman Green, London), 3rd edn, 1975, 479.4. LUTTKE, W., Z. Elektrochern., 61 (1957), 302.5. CHAKRAVORTY,A. & KALlA, K. C., J. org. Chern. 55
(1970), 2231.6. KALlA, K. C. & KUMAR,A., Indian J. Chern., 16A (1978),
52,7. PFEIFFER,P. & RICHARZ,J., Ber. dt. chern. Ges., 61 (1928),
103.8. GODYCKI, L. E. & RUNDLE. R. E., Acta. Crystallogr., 6
(1953), 487.9. FRASSON,E., PANATTONI,C. & ZANNETTI,R., Acta. Crys-
tallogr., 12 (1959), 1027.10. FRASSON, E., BARDI, R. & BEZZI, S., Acta. Crystcllagr.,
12 (1959), 201.1J. KALlA, K. C. & CHAKRAVORTY,A., Inorg. Chem., 7 (1968),
2016.12. BLlNC, R. & HADZI, D., J. chern. Soc., (1958),4536.13. BURGER,K., RUFF, I. & RUFF, F., J. inorg. nucl. Chem.,
27 (1965), 179.14. PATEL. N. J. & HALDAR, B. c., J. inorg. nuc/. Chern., 29
(1967), 1037.15. AVRAM, M. & MATEESCU, GH., Infrared spectroscopy
(John-Wiley, New York), 1966, 213.16. HADZI, D., J. chern. Soc., (1956), 2725.
Binuclear Thallium(Ill) Complex of Triethanolamine
M. R. UDUPA*, V. R. S. RAO & G. TATAIHtDepartment of Chemistry, Indian Institute of Technology,
Madras 600 036
Received 23 April 1979; revised and accepted 16 June 1979
The interaction of TI(III) chloride with triethanolamine,H.TEA, results in the isolation of a binuclear TI. (TEA)(HTEA)CI complex, which has been characterized by X-ray powder diff-raction pattern, thermal behaviour, conductivity measurements andelectronic and infrared spectral studies.
TRIETHANOLAMINE (HgTEA) is basi-cally a tetradentate ligand and forms a variety
of complexes with transition and representativemetals':". Though the alcoholic protons in HgTEAare not acidic, on bonding to a metal theymay become acidic, which facilitates deprotonationresulting in anionic metal complexes", Thecoordinated alkoxide groups may further formadditional bonds through the oxygen bridges to givepolynuclear complexes". In this communication,the preparation, thermal behaviour, X-ray powderdata and spectral characteristics of a Tl(III) complexof HgTEA, TI2(HTEA)(TEA)Cl are reported.
The complex was prepared by mixing an aqueoussolution of HTIC14, obtained by dissolving Tl20a
tDeceased
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