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taining a polynitratometal ion, although i t is not unlikely that others exist. It is to be noted that in his work on the preparation of anhydrous metal nitrates Addison3obtained a compound Zn(NO&NnO4 for which he suggested the structure (NO+)2[Zn(ONOZ)d]and he also mentions isolating Co(NO&2Nz04 (red-purple) which is presumably of the same nature. It would appear worthwhile to attempt the preparation of other compounds containing [M(ON02),] anions either by the simple method suggested here or by other metathetical reactions. However, we do not plan to undertake such studies in This Laboratory. Our particular object in preparing this compound was to examine its spectral properties and electronic structure parameters. It recently has been shown4 that there are tetrahedral complexes of Co(I1) which have rather small decrements in the interelectronic repulsion parameter, B, and rather low electronic absorption band intensities. Since several of these are of the type CoL2(0N02)2i t seemed likely that the tetrahedral [CO(ONOZ)~]~ion should also have these properties. From the electronic spectrum we obtain2 A = 4660 ern.-', B = 855 cm.-' andf(v3) = 1.94 X Thus on the previously reporfed plot of AB as. f( va) ,5 the point for [ C O ( O N O ~ ) ~falls ] ~ - very close to the best line through the points for the other compounds. I t is also interesting that the A value places the nitrate ion further toward the strong end of the spectrochemical series than are other oxygen-coordinating ligands. We are grateful to the U. S. Atomic Energy Commission and the Alfred P. Sloan Foundation for financial aid.
in a potassium bromide disk and benzene solution revealed absorption in the 600 and 900 mp regions characteristic of tetrahedral nickel(I1j complexes. The absorption maxima in millimicrons observed in benzene solution (molar extinction coefficients in parentheses) are: 405(2060), 455(2220), 575(320), 925(90), and lOOO(110). A magnetic moment of 3.44 Bohr magnetons was obtained for the solid. This is lower than the values reported for NiXk-2 anions,* and for tetrahedral ((CCH6)3PO)ZN~X~ but NiXn and ( ( C G H ~ ) ~ A S O ) ~cornple~es,~ higher than the values reported for the tetrahedral ( (CaH6)3P)2NiX2 compound^.^ Diiodobis-(pyridine)-nickel(I1) was prepared by refluxing a mixture of anhydrous nickel(I1) iodide and pyridine for eight hours. The excess pyridine was decanted and the solid product washed with boiling alcohol. A light green solid, diiodotetra-(pyridine)-nickel(II) separated from the alcohol on cooling. This was heated a t 110' in an Abderhalden apparatus until the uniform dark green product was obtained. Anal. Calcd. for CloHl&XN2: Ni, 12.47; I , 53.92. Found: Ni, 12.63; I, 33.56. Diiodobis-(P-picoline)-nickel(I1)was prepared in a similar manner, except that the reaction mixture was refluxed only 30 minutes. After decanting the excess picoline, the light green tetrapicoline complex was washed with petroleum ether before converting to the dark green bispicoline complex by heating. The tetrahedral configuration of this compound is indicated by the similarity of its infrared spectra with that of the corresponding blue cobalt(I1) complex and by its visible and near infrared spectra in KBr and benzene solution. The absorption maxima in benzene are 405 mp (2040), (3) C. C. Addison and B . J . Hathaway, "Recent Aspects of t h e 462(2060), 585(300), 925(90) and 1000(100). A Inorganic Chemistry of Nitrogen," t h e Chemistry Society, London, value of 3.21 was obtained for the magnetic moment Special Publication pio. 10, 1957, p, 41. of the solid. Anal. Calcd. for C12H1412NiN2: (4) F. A. Cotton and R. H. Soderberg, J. A m . C h e m . .Sac., 84, 872 C, 28.90; H, 2.83. Found: C, 28.27; H , 3.47. (1962). ( 5 ) AB = 967 - B. It was expected that steric effects would prevent DEPARTMENT OF CHEMISTRY A N D LABORATORY OF halogen bridging in the bis complexes of a-picoline CHEMICAL AEZDSOLIDSTATEPHYSICS with NiC12 and NiBr2. This appears to be the MASSACHUSETTS ISSTITUTEOF TECHNOLOGY F. A. COTTON 39, MASSACHUSETTS T. G. DUNNE case. These compounds are dark blue, indicating CAMBRIDGE that they are tetrahedral. Solid dichlorobis-(aRECEIVED MARCH31, 1962 picoline)-nickel(I1) absorbs a t 555 and 950 mfi (weak) and has a magnetic moment of 3.3. Solid TETRAHEDRAL COMPLEXES CONTAINING dibromobis-(a-picoline)-nickel(I1) absorbs a t 562 NITROGEN-TO-NICKEL BONDS' and 950 nip (weak) and has a magnetic moment of Sir: 3.35. The dibromo complex was prepared by reWe are unaware of any evidence previously re- fluxing anhydrous nickel bromide in an excess of ported for a tetrahedral configuration for solid a-picoline for 30 minutes. The excess ligand was complexes containing nitrogen-to-nickel bonds. removed under vacuum and the product washed The infrared spectrum of dark green diiodobis- several times with petroleum ether and then dried (pyridine)-nickel( 11) was observed to be character- over phosphoric anhydride. It could not be reistic of tetrahedral compounds of the type Mpy~X2, crystallized as i t decomposes in the usual solvents. particularly in the position of the absorption as- Anal. Calcd. for Cl2Hl4Br2XiX2: Ni, 14.26; sociated with the C-H in-plane bending vibration 35.60; H , 3.47. Found: Xi, 14.15; C, 34.36; a t 1068 cm.-l and the splitting (755 and 753 cm.-') H , 4.17. The dichloro compound was prepared by associated with coupling between C-H out-of- adding equivalent portions of nickel(11) chloride plane bending vibrations in adjacent pyridine hexahydrate and a-picoline to absolute ethanol. rings. A typical splitting also was observed in the After considerable stirring the mixture was placed 700 cm.-' region, with peaks a t 693 and 689 ern.-'. in a vacuum desiccator over sulfuric acid for several The mectrum differed in these resDects from those
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May20, 1962
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days. The product was washed several times with petroleum ether. It could not be recrystallized because of decomposition in the usual solvents. Anal. Calcd. for C12H&12NiN2: Ni, 18.58; C1, 22.45. Found: Ni, 18.70; C1, 24.17.
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I1
CHEMISTRY AND RADIATION LABORATORIES Ozonization of I1 and treatment with hydrogen UNIVERSITY O F NOTREDAME S R . M. DESNIS GLONEK 2-methylXOTREDAME,IXDIANA COLUMBA CURRAN peroxide gave 2-isopropyl-5-oxocaproic, FLORIDA STATEUNIVERSITY glutaric, and levulinic acids (isolated as methyl TALLAHASSEE, FLORIDA JAMES 1'. QUACLIANO esters by gas-liquid chromatography, silicone, RECEIVEDMARCH21, 1962 110'). These three acids account for all twenty
carbon atoms of the cembrene molecule. Since all are bifunctional, and since cembrene possesses but one ring, the dihydro derivative and therefore Sir: cembrene must contain a fourteen carbon ring. Cembrene (I) is a crystalline diterpene hydro- There are eight possible structures for the lithiumcarbon (CZOH32, mol. wt. 272 (mass spectrum'), liquid ammonia produced dihydrocembrene (11) 238' (c 1.13, chf.) ) first which could yield these three degradation products. m.p. 59-60', [cL]'~D isolated by Haagen-Smit, Wang and M i r ~ v , ~ Ozonization of cembrene and treatment with from the oleoresin of Pinus albicaulis and subse- hydrogen peroxide gave acetic, malonic, 2-isoquently found to occur in exudate of many other propyl-5-oxocaproic, and levulinic acids (isolated pine tree^.^'^ Cembrene,6 upon catalytic hydro- as methyl esters by gas-liquid chromatography, genation over Pd/C in ethyl acetate, yielded a silicone, 110'). When the ozonide was treated liquid saturated octahydro derivative (CZOHIO, with sodium iodide, then p-nitrophenylhydrazine, mol. wt. 280 (mass spectrum2) ), establishing the the p-nitrophenylosazone of pyruvaldehyde was presence of four double bonds and one ring in the isolated. The absence of 2-methylglutaric acid starting material (I). The ultraviolet and infrared and the appearance of malonic and pyruvic acid spectra of cembrene, X",tH 245 mp ( E 17,000), moieties permits placement of the olefinic bond vzYx 1660 (w), 1640 (w), 967 (s), 840 (m), 811 (m) which was reduced to form dihydrocembrene I1 cm.-', indicated the presence of a conjugated diene and suggests eight related structures for cembrene. Catalytic hydrogenation of cembrene over 57, as well as trans-disubstituted and trisubstituted double bonds. From the n.m.r. spectrum' (quan- Pd/C in ethyl acetate gave a mixture of three titative) of cembrene, it was determined that dihydrocembrenes (gas-liquid chromatography, silithere was an isopropyl group attached to a satu- cone, 200'). The major component I11 (no maxirated carbon (two doublets centered at 9.09 and mum in the ultraviolet; n.m.r., 3 vinyl protons; 9.20 p.p.m., G protons), two methyl groups on no 970 cm.-' band) was different from dihydrodouble bonds (8.47 and 8.38 p.p.m.), and one cembrene I1 and was formed by the hydrogenation methyl group on a conjugated diene (8.20 p.p.m.). of the trans-disubstituted double bond of the The presence of five vinyl protons was established conjugated diene. by a broad absorption band between 3.80 and 5.30 p.p.m. containing a sharp doublet a t 3.80 and 4.07 p.p.m. equal to one proton. The low field position of this doublet characteristic of a proton on a trans-disubstituted double bond further indicated I11 IV that the bond was part of the conjugated diene Ozonization of I11 and treatment with hydrogen system. Reduction of the conjugated diene system of I peroxide gave rise to approximately equal amounts with lithium in liquid ammonia gave a mixture of of neutral and acidic materials. The major comdihydrocembrenes,8 whose ultraviolet spectrum ponents of the latter were levulinic and malonic possessed no maximum above 205 mp, and which acids. The eight possible structures of cembrene may be consisted of two compounds in the ratio of 85:15 (g.l.c., silicone, 215'). The infrared absorption reduced to four by elimination of all structures not a t 973 cm.-l of the major component (11) indicated containing a trans-disubstituted double bond as part the continued presence of the trans-disubstituted of the conjugated system. Two of the remaining double bond and the n.m.r. spectrum showed the four structures also may be eliminated, since the product from their dihydrogenation would not presence of four vinyl protons. yield levulinic and malonic acids upon ozonization. (1) This work was supported in part by Grant No. 14526, National The two remaining structures are isoprenoid I Science Foundation. and the non-isoprenoid IV. ( 2 ) We are indebted t o Dr. D. P . Stevenson of Shell Development Cumpany for all t h e mass spectral d a t a quoted in this work, Hydroboration of 111, then oxidation, gave a (3) A. J. Haagen-Smit, T . H . Wang, and K. T. Mirov, J. A m . triol mixture V, whose n.m.r. spectrum showed a P h a r m . A s s n . , Sci. E d . , 40, 557 (1951). broad peak a t 6.28 p.p.m. corresponding to three ( 4 ) N. T. hlirov, "Composition of G u m Turpentines of Pines," Technical Bulletin S o . 1239, U. S. Department of Agriculture, June, protons attached to carbon atoms bearing hydroxyl 1961. groups. Acetylation of V with acetic anhydride ( 3 W. G. Dauben and C. Ashcraft, unpublished observations. and sodium acetate a t 145' gave the triacetate VI ( 6 ) We are indebted t o Dr S . T.Mirov for t h e supply of oleoresin whose n.m.r. spectrum showed a broad band a t ( 7 ) All chemical shifts are quoted in reference t o t h e r scale. ( 8 ) Satisfactory analyses were obtninad for all new compoundr. 6.20 p , p m corresponding to three protons atCEMBRENE, A 14-MEMBERED RING DITERPENE HYDROCARBON'
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