IR spectra of acetamide complexes were recordedon Specord 75 in nujol phase whereas those of other~ompounds were recorded on a perkin-Elmer gratingmfrared spectrophotometer model 577 in KBr.

The imido and imidoisopropoxy derivatives ofzirconium(lV) were obtained by heating Zr(OPri)4'PriOH with amide in benzene under reflux. Typi-cally, acetamide (0.249 g) was added to Zr(OPri)4'PriOH (l.37 g) in dry benzene (70 mI). The mixturewas refluxed for 12 hr, during which time liberatedisopropanol was collected in the form of a benzene-isopropanol azeotrope at 72°. The excess of benzenewas removed from the insoluble product by frac-tionation at 80°. The white insoluble product obtainedwas washed first with ethanol (3 X 1.5 ml) to removetraces of unreacted acetamide, if any, present andfinally washed with dry benzene (3 X 2 mI). Thecomplex was dried to constant weight under reducedpressure (10-2 torr) at room temperature. (PriO)JZr(NHCOCH3), yield 90%. [Found: Zr, 27.84;N, 4.25. Calc. Zr, 27.87; N, 4.97%]. Iso-propanol in the azeotrope: [Found: 0.420 g; Calc.for replacement of two moles, 0.423 g]. The details ofother reactions are summarised in Table 1.

Zirconium was determined after ignition to dioxideand nitrogen was determined by the kjeldahal's method.Isopropanol was estimated by oxidation with normaldichromate solution in 12.5 % sulphuric acid and backtitration of the excess dichromate iodornetrically'",

Thanks are due to Prof. R. N. Kapoor, ChemistryDepartment, University of Delhi, for helpful dis-cussions. Thanks are also due to Prof. R. C. Kapoor,Head, Department of Chemistry, University ofJodhpur, for providing laboratory facilities and theUGC, New Delhi for a research fellowship to oneof us (KRN).

References1. BRADLEY, D. C., Progress in inorganic chemistry, Vol. 2

(Interscience, New York), 1960, 303.2. MEHROTRA, R. C., Inorg. chim. Acta Rev., 1 (1967), 99.3. BRADLEY, D. C. & FISHER, K. J., M. T. P. Int. Rev. Sci .•

Pt. I, Inorganic chemistry series. 1 (1972), 5.4. BHATIA, D., Thio derivatives of aluminium, titanium &

zirconium Ph. D. Thesis, University of Jodhpur, 1973.5. UTTAMCHANDANI, J., Reactions of AI. n, z-, Nb & Ta

alkoxides with N & 0 donor ligands, Ph.D. ThesisUniversity of Jodhpur, 1977.

6. JAIN, S. C. & RIvEST, R., J. inorg. nucl. Chem.. 29(1967), 2787.

7. MATSUBAYASHI, G. E., HIROSHIMA, M. & TANKA, T.,J. inorg. nucl. Chem., 33 (1971), 3787.

8. SRIVASTAVA, T. N., Indian J. Chem., 12 (1974), 98.9. PAUL, R. C., SINGH, H. & CHADDHA, S. L. Indian J.

Chem. 15A (1977), 121.10. PAUL, R. C., CHADDHA, S. L. & YASISTH, S. K., J. less-

common Metals, 16 (1968), 288.11. SHARMA, K. K., MEHROTRA, S. K. & MEHROTRA, R. C.,

(Personal Communication).12. NOTES, J. C., Recl. Trav. chim. Pays Bas, Belg., 84 (1965),

799.13. BRADLEY, D. C. & WESTLAKE, A. H., Proceedings of

symposium on coordination chemistry, Tihany, Hungary,1964.

14. RICHARDS, R. E. & THOMPSON, H. W., J. chem. Soc.,(1974), 1248.

15. RICHARDS, R. E. & THOMPSON, H. W., The chemistry ofpenicillin (Princeton Univ. Press, N. J.) 1949, 390.

16. ELLIOTT, A., Infrared spectra and structure of organiclong chain polymers (Edward Arnold Ltd., London),1969, 85.

NOTES

17. KONORALOV, L. Y., KASLESSNIKOVA, I. S. & SHINYAKlN,Y. N., Zh. neorg. Khim., 15 (1970), 1993.

18. ZYGMUNT, W., Rocz, Chem., 49 (1975), 1069.19. KLEBE, J. E., BUSH, Jr., J. B. & LYONS, J. E., J. Am.

chem. Soc., 86 (1964), 4400.20. BARRACLOUGH, C. G., BRADLEY, D. c., LEWIS, J. &

THOMAS, I. M., J. chem. Soc., (1961), 2601.21. KATRIKZKY, A. R., Physical methods in heterocyclic

chemistry, Vol. 2 (Academic Press, New York), 1963.22. NAHAR, K. R., SOLANKI, A. K. & BHANDARI, A. M~,

Z. anorg. allgem. Chem., 449 (1979), 187; SOLANKI,A. K., NAHAR, K. R. & BHANDARI, A. M., Synth. React.Inorg. Met. Org. Chem., 8 (1978), 335

23. BRADLEY, D. C., ABAD-EL-HALIM, F. M. & WARDLAW, W.,J. chem. Soc., (1950), 3450.

Synthesis & Characterisation of New Molybdenum(VI)Complexes

P. S. ZACHARIAS* & C. SUBRAMANI

School of Chemistry, University of Hyderabad,Hyderabad 500 001

Received 9 April 1979; revised and accepted 3 August 1979

Some new molybdenum (VI) complexes of triazene f-oxldesof composition Mo02L. are reported. Evidences suggest cis-dioxo structure for them.

THE recognition of molybdenum as an active sitein many biosystems has given a new impetus

to the synthesis and study of new molybdenumcompounds in different oxidation states'. Duringthe course of our study of the transition metal com-plexes of triazene l-oxides (I, X = H, OCH3,

OC2Hs), new molybdenum compounds were synthe-sised and studied using these ligands, since very little

work is reported on molybdenum complexes. Forconvenience the ligand system (1) has been abbrevia-ted as (R-C6H4X) and the complex as (R-C6H4X)zMo02·

The ligands used here were synthesised by a generalmethod". The molybdenum complexes were pre-pared as follows: one mol equivalent of molybdenum(ammonium molybdate) was dissolved in minimumquantity of water by adding a few drops of ammoniasolution. This was added to a clear solution of 2 molequivalent of ligand in methanol with stirring.The solution was acidified with cone. HN03 topH 3-4. An orange coloured solution was formedwhich on cooling gave yellow-orange crystals. Thecrude product was recrystallised from methanol anddried in vacuo. Characterisation data of the com-plexes are presented in Table 1.

All the molybdenum complexes are stable in airand soluble in many organic solvents. These com-plexes are diamagnetic and monomeric in methanol

71

INDIAN J. CHEM., VOL. 19A, JANUARY 1980

TABLE 1-CHARACTERISATION DATA AND IR FREQUENCIES FOR THE MOLYBDENUM CoMPLEXES

C(%) H(%) Mo (%)* tIR VmaxCompound (cmr<)

Calc. Found Calc. Found Calc. Found

(C.H.-C.H.)2Mo02 52.18 52.30 3.62 3.60 17.37 16.85 930,960(CeH5-C.H.OCH3)2Mo02 50.98 51.24 3.92 3.90 15.67 15.02 905,940(CH3-C.H5)2Mo02 39.26 39.05 3.74 3.62 22.42 22.50 920,950(CH3-C.H.OCH')2MoO• 39.34 39.62 4.10 4.18 19.66 19.06 918,952(C.H.-C.H5)2MoO• 42.11 41.R9 4.38 4.21 925,954(C.H5-C.H.OCH3).MoO. 41.86 41.05 4.65 4.51 900,950(C2H5-C.H.OC2H.).MoO. 44.12 44.81 5.14 5.04 17.63 16.85 900,930

*Determined gravimetrically as oxinide!+Recorded in KBr on a Perkin-Elmer spectrophotometer, model 297.

(mol. wts determined with Knaver vapour pressureosmometer). These experimental results suggestthat these molybdenum complexes can be representedas Mo02L2• This is in agreement with the fact thatmajority of Mo(VI) complexes of organic ligandshave the composition+" Mo02L2 while Mo(V)complexes are dinuclear with oxo-bridges, thoughsome monomeric species are reported recently".

In complexes of this type the dioxo groups can beeither cis or trans. The cis-dioxo grouping ischaracterised by two IR and Raman active stret-ching modes while trans-dioxo by a single IRactive and a single Raman active stretch at differentfrequencies. The presence of two Mot), bands inthe region 900-960 cm" in six-coordinate MoO~+compounds is strongly indicative of the cis dioxostructure". The IR frequencies observed for ourcompounds, presented in Table 1, correspondwith the bands observed for other six-coordinatecis-MoO ~+ species!".

Mo(VI) octahedral complexes do not showany electronic transition in the IR and visible regionsbut exhibit some high intensity transitions in theUV region. The presence of bands in the 27,00030,000 cm" region has been taken to be characteris-tic of the molybdenyl groups. In ~-djketonates anintense band assignable to O--,>-Mo charge transferhas been located near 52,000 cm". The molyb-denum complexes reported here exhibit an intensetransition at 25,000 cm", No other transition isobserved in the IR or visible region. We couldnot go below 26,000 cm" in the UV region dueto instrument limitation. The transition at 25,000cm? is a ligand transition since the same transitionis observed in other triazene I-oxides. The absenceof any other transition in the visible or IR region isan indirect evidence to show that molybdenum is notin the V oxidation state in these complexes".

References

1. EDWARD, I. STIEFEL, Progress in inorganic chemistry,edited by S. J. Lippard, (John-Willey, New York),22 (1977), 1.

2. CHAKRAVORTY,A., BEHERA, B. & ZACHARIAS,P. S.,Inorg. Chim. Acta, 2 (1968), 85.

3. VOGEL, A. I., A text book of quantitative analysis, (ELBS,London) 1975; 508.

72

4. MOORE, F. W. & RICE, R. E., Inorg. Chem., 7 (1968).2511; MOORE,F. W. & LARSON, M. L., Inorg. Chem.,6 (1967), 998.

5. YAMANOUCHI,K. & YAMADA, S. Inorg. chim. Acta,9 (1974), 161; YAMANOUCHI,Y. & YAMADA, S., Inorg.chim. Acta, 9 (1974), 83.

6. YAMANOUCHI,K. & ENEMARK, G. H., Inorg. Chem.,17 (1978), 1981.

7. Corrox, F. A. & WING, R. M., Inorg. Chem., 4 (1965),867.

8. BARTECKI,A., Cliem, Zvesti, 19 (1965), 161.9. KAy, A. & MITCHELL, P. C. H., J. chem. Soc. (A

(1970), 2421.

Di-2-pyridyl ketone & Benzotriazole Complexesof Zinc(II)

B. PRADHAN& D. V. RAMANARAo·Department of Chemistry, Regional Engineering College,

Rourkela 769 008

Received 17 May 1979; revised 21 July 1979; accepted3 August 1979

Zinc(II) pseudohaJides (cyanate, thiocyanate and azide)have been reacted with di-2-pyridyl ketone (dpk) and benzotri-azole(bzt) in ethanolic medium and six compounds have beenisolated and characterised on the basis of analytical, conductanceand infrared spectral data. The compound Zn(dpk)(N3)2 isfour coordinated; Zntbzt), (NCO)2 and Zn(bzt)3(N3). arefive coordinated; and Zn(dpk).(NCS)2' Zn(dpk).(NCO)2 andZn(bzt).(NCS)2 are six coordinated.

THE ligands, di-2-pyridyl ketone (dpk) andbenzotriazole(bzt), are interesting ligands

as they exhibit different modes of coordination.Di-z-pyr idyl ketone may function as a neutral biden-tate ligand coordinating either through N, 0 orN, N and a number of its complexes withdifferent metal ions, viz. Cu(II), Mn(II), Fe (II) ,Co(I1), Ni(Il), have been reported>". Benzotria-zole may function as a neutral mono dentate or aci-dic bidentate ligand and its complexes with Pd(II),Cu(1I) , Ni(II), Co(I1 & III), Rh(II), Os(III),Mn(I1)6-13 have been already reported. The pseudo-halides, thiocyanate, cyanate and azide, are interest-ing for their different modes of coordination.In the present note an attempt has been made to