May 20, 1961
COMMUNICATIONS TO THE EDITOR
2393
-H G must contain bromo-I, which although originally I1 I I I b ---+ covalent, may ionize in appropriate solvents to give 111. For cations obtained by protonation of carotenoids an upper limit for A,, has been calculated by For two double bonds, conjugated with a positive charge, this limit is 484 mp, indicating that I11 is not itself the magenta species, but rather a precursor to it. t From the magenta solutions three dimeric +HD' hydrocarbons are recovered, with ultraviolet spectra, characteristic of polyenes. Each upon protonation regenerates the magenta color instantaneously with high e. This indicates that in its simplest form the magenta species is also dimeric. The absence of chromophores of different length, corresponding to progressive extension, follows from the observation of only a single peak a t 552 On the other hand, hindrance is absent in A, the mp. The acetic acid solvent was evaporated in vacuo addition product of I1 to IIIb, as well as in the at 25O from a magenta solution obtained by proto- secondary rearrangement products E and F with nation of 11. The remaining viscous magenta resi- double "retro" structureg (B and D show some due was triturated repeatedly with pentane so as crowding). In VI and VI1 bands a t : 858 (mw), 1720 (w) to extract all but the most strongly protonated compounds. Ice cold aqueous potassium hy- (overtone of 858), 3078 (VW)cm.-l indicate vinyldroxide then was added. Extraction of the result- methylene exocyclic to a strained ring such as in ing suspension with pentane, then evaporation of 11. The low relative intensities indicate a ratio the solvent, gave an orange viscous residue. Sub- of vinyl-methylene to CH3 considerably less than limation a t 0.1 mm. (Dry Ice in condenser) yielded : half that in I1 (2:4). A sharp band a t 800 cm.-' (1) a t SO', a yellow hydrocarbon (VI), after resubin V I and VI1 is absent limation, partially crystallizable from a minimum (mw) [:>C=C(r] of pentane a t -10' to give yellow needles, m.p. 66-75' (prob. impure with VII). Anal. C, 88.85; in VIII, which instead exhibits a sharp band a t H I 11.03; mass spec. mol. wt., 296 (CzzH32). 333.6, 370.0, 390.0 (sh) mp; Emax X , M), . 'L" 2.165, 3.020, 2.890, 0.62'; A ~ a ~ a C o o HCHaS0sH(0.05 cm.-' region, all three exhibit coinplex absorption 552 mp; emax 48,800. Can-Price reactionla A:zcl:, SbC13, 563, 602 mp. ( 2 ) a t 100-110', an orange with a main band a t 1620 cm. (s), These spectra are consistent with the assignhydrocarbon (VII) ; after resublimation and reD. The crystallization from pentane a t - lo', orange ments VI = F, VI1 = E, VI11 = B needles m.p. 140-145'. Anal. C, 89.03; H, 10.97; exceptionally stable magenta species then is premass spec. mol. wt., 296 (C22H32). 350.0, sumably the ion C, which is similar to certain caro369.0, 390.0mp; emax X 1.88, 2.66, 2.32.' tenoid ions.6 Thanks are due to Professor S. Winstein for conA,*,CHaCOOH,CH:SOaH(0.05 W , 552 mp; Emax 49,600. Carr-Price reaction : A ~ ~ C 1 3 ~ S b C 1 a563, , 602 mp. structive criticisms. (3) a t 130°, an orange hydrocarbon (VIII); after CALIFORNIA RESEARCH CORPORATION CALIFORNIA L. DE VRIES resublimation and crystallization from pentane a t RICHMOND, RECEIVED MARCH 30, 1961 -lo', m.p. 151-153', orange needles. Anal. C, 89.23; H, 10.72; mass spec. mol. wt., 296 (Cz2Ha2). Xp?ts"e , 350.0, 369.0, 390.0 mp; Emax X DIPOLE MOMENTS OF BIS1.88,1.27, 1.66, 1.41; 7 A ~ ~ s C 0 0 H ~ C H ~ S 0 ~ HM~ 0) ,~ 0552 5 CYCLOPENTADIENYL TITANIUM AND ZIRCONIUM DICHLORIDES mp ; Emax 49,300. Carr-Price reaction; X22Cla,SbC18 563, 602 mp. Sir: The ultraviolet spectra especially of VI and VII, Metal compounds involving $-bonded bis-cyclowith three intense maxima, are characteristic of pentadienyl groups have evoked a great amount of conjugated polyenes with unhindered coplanarity.9 interest in the past decade, and a recent review' I1 may add to 111either as I I I a or IIIb. Dreid- has critically surveyed the bonding aspects and ing stereomodels10indicate that crowding in the pri- inorganic and physical chemistry of these materials. mary addition product of I1 to IIIa is prohibitive The relative positions of the cyclopentadienyl in all steric configurations. rings have been elucidated by crystal structure and dipole moment determinations for ferrocene and a (6) A. Wassermann, J . Chcm. SOG.,979 (1959). (7) Initially the hydrocarbon was dissolved in a minimum of isofew other similar materials, but no conclusive octane. evidence as to the structure of bis-cyclopentadienyl
zm
+
(8) E. H. Carr and E. A. Price, Biochcm. J . , 31, 497 (1926). (9) W. Oroshnik, c l al., J. A m . Chem. SOC., 74, 295 (1953); 76, 5719
(1959). (10) Rinco Instrument Company, Greenfield, Illinois.
(1) G. Wilkinson and F. A. Cotton in "Progress in Inorganic Chemistry," Vol. I, edited by 1'. A. Cotton, Interscience Publishers Inc., New York, N. Y.,1959, pp. 1-124.
2394
~ O M M U N f C X T I O S STO T H E
EDITOR
Val. bY
titanium dichloride (I) or its zirconium analog TABLE I (11) has been found. LVilkinson and Birmingham2 BIS-CYCLOPESIADIEX~YL TITANIUM DICHLORIDE demonstrated from infrared data that a monomeric Concn Dielectric Dmsity (wt. fract.) constant e (g./cc.) 7% (qo)? s-bonded “sandwich” structure exists for I and 11. 0.000869 2.281 ... Sloan and Barber3 reinforced these observations ,001‘329 2.300 ... by- proton magnetic resonance data on I and 11, ,002870 2 ,313 ... but no mention has been made o€ the spatial con,00169 2.290 0.8695 .. ... figuration of the rings. 000615 2 279 ,8690 ... ... “Xngular” sandwich structures have been postu.000327 2.269 ,8689 ... ... lated for bis-cyclopentadienyl tin and lead on the Solvent 2.265 ,8684 ... ... basis of dipole moments and other measurements,4 and X-ray measurements on (C5H&TiC12.illL ZIRC0.YIC.M L)ICHLOKIDE Concn. (C2H5)2 JIII).’ (wt. fract.) 730D (1ID)S 11-e wish to report that the hzgh values of the 0,002978 2.303 1 ,49439 ‘1 23337‘3 dipole moments obtained, 6.3 and 5.9 D for I and 1 .49454 2.23363 ,001951 2.291 11, respectively, indicate that there are four es.001052 2 276 1.19448 2,23347 sentially equivalent bond angles and that the 1 ,49440 2 23323 ,000472 2.273 structure is similar to the [ (CjH&TiCls ] grouping Solvent 2 . 2 6 5 1 49139 in 111, i.e., approaching the tetrahedral configuration as depicted in Fig. A . I t is of interest that temperature controlled to O.O.Jo. Densities were the structure appears to be independent of the measured in a 23 ml. pycnometer.fi oxidation state. The data were interpreted by the method of Guggenheim and Prue’ and of Halverstadt and Kumler.8 least squares analysis was applied with these results. Ti CoIrlpound I
Zr Compound I1
+(Debyes)
liethod
6.26 i0,39 6 . 2 % zk 0.39 3.90 z!= 0.38
Refractive iiidcs Density
Refractive index
The uncertainty given represents the 937; confidence interval of the data. ( 0 ) Tlre dielectric constant, refractive index a n d density measurements were performed by J. R. Murray of these Laboratories. (7) E. -4.Gupgenheim and J. E . Prue, “Physicochemical Calculations,” Interscience Publishers, Inc., New York, N . Y , 1935, VI). IOfi, el seq.
(8) I . F. Halverstadt and U‘. D. Kumler, J . A r i ? . Chcii?. S O L , 64. 2Y88 (1942).
Fig. 1.
The measurements were conducted in benzene using the “dielectric constant-refractive index” method for I and 11, and the “dielectric constantdensity” method for I. Measurements made both on freshly prepared solutions and on solutions one day old were identical, suggesting that changes in solution, if any, had no effect on the dielectric constant. The results are shown in Table I. Dielectric constant measurements were made a t 30.0° using a heterodyne-beat circuit consisting of two electron coupled oscillators, one controlled with a quartz cryshl a t 5 i 6 . 3 kc. and the frequency of the other one controlled by the variable capacitance. X Balsbaugh model cell made of Pyrex and monel metal was used. The volume was 50 nil., and the interplate air capacitance was 39.4 p p f . Refractive index was measured with a Bausch and Lomb Precision ,ibbe refractometer, ( 2 ) G . Wilkinson arid J . .\I. Hirmingh;irn, J . .Ain. Chciii. S a . , 76, 4281 (195li 13) C I.. SIoan and LV.A Rarher. 9 fl) 1. D. l3.rx.e. I> I‘ I~:vansancl C ( 19 .XI). (S) G. Nxtta, F. Curradini arid I . \V, Bassi, J . 21;i~.Chciii. Sac., 8 0 ,
-i -~- . (1958). )
CHEMICAL RESEARCH A N D RESEARCH SERVICE DEPARTMENTS CENTRAL RESEARCH DIVISION S. .I.GIDDISGS R. J. BEST -&ERICAN CYANAMID COMPAXY STAMFORD, CONSECTICUT RECEIVEDMARCH 25, 1961 THE CONFORMATION OF METALADENOSINE TRIPHOSPHATE COMPLEXES IN SOLUTION
Sir: The fact that adenosine triphosphate (4TP) forms strong complexes with divalent metal ions is well known and quantitative and kinetic studies3have been caried out by several workers. The most important metal binding sites are undoubtedly the phosphate groups, but the role of the rest of the molecule in forming the metal complex has given rise to much speculation ( c f . reference 4 for a review of this subject and pertinent literature citations). Solid state infrared studies, (1) A. II LZartell and G . Schu-arzenbach, H e l w . Ch$iii A l c l a , 39, 033 (183fi).
( 2 ) R. A . Albertp a n d 11. M . Smith, J . . l i n Chc~li..S’oc., 78, 237H ( I 0 SFi). I,’() H.
Uiehler, A I I-igen and C;. C;. Iinmrnes. i!
1SB. . i R 1 (1960). (i)Yi K. Atkinson and I
