COMMUNICATIONS TO THE EDITOR
2020
with its partner in the planar complex in one of the Amolecular orbitals of the c ~ m p l e x . ~ The Co(TDT)z- anion is the first example of a highspin, planar ds metal complex. The exceptionally weak field of the T D T ligand is indicated from the position of the first band in Ni(TDT)2-, which is tentatively assigned t o the dxy + dX2--2 transition. For a AI (xy + x 2 - y2) in the neighborhood of 7000 cm.-l, the planar Co+ complex is predicted to be high-spin, even in the absence of axial interactions6 Since the electronic spectrum of [(C~H&AS(CH~)] [ C O ( T D T ) ~is] the same in acetone, acetonitrile and pyridine, axial effects probably are of no importance in this case The M(MNT)2- complexes, which we reported earlier,' on oxidation give M(MNT)z- complexes,s which apparently are composed of M + and M N T radical anion m ~ i e t i e s . ~Of interest is the reaction of Fez+ and MNT, which gives Fe(MNT)2- directly. The Fe(MNT)2- complex has S = 3/2, with d-d electronic bands a t practically the same energies as planar, high-spin CO(MNT)~*-.Thus Fe(MNT)2- and Fe(TDT)s- are probably the first examples of high-spin Fe+ in a planar situation. It is important t o note that the ligand field strength of MNT is the same as a dianion with d7 Co2+ and as a radical anion with d7 Fe+. (5) Evidence has been presented t h a t t h e Ni
({'if:)
complex
is planar and contains Nil and two radical anions. T h e two odd electrons are supposedly paired in t h e a-molecular system of the complex; see G. N. Schrauzer and V. Maywea. The . . J. A m . Chem. Sac., 843 3221 (1962). +
):mplex
can be reduced t o h'i
(";/..)
:which
\S/'\Ph 2 has S = 1/z and shows a highly anisotropic e.s.r. spectrum: see ref. 8. T h e reduced complex may be electronically similar t o N ( T D T ) z - . (6) C. J. Ballhausen and A. D. Liehr, i b i d . , 81, 538 (1959). suggested t h a t high-spin, rigorously planar ds Nil is possible for a AI less t h a n 10,000 cm. (7) The RII(MNT!zZ- complexes have been shown t o consist of Ma+ and +
R. Williams, I. Bernal and E. Billig, i b i d . , 8 4 , 3596 (1962). ( 8 ) For M = N i , Pd and P t , see A. Davison, N. Edelstein, K. H. Holm and A, H . Maki, i b i d . , 85, 2029 (1963). We thank Dr. R. H. Holm for allowing us t o see a preprint of these results prior t o publication. (9) T h u s for the coplanar ring system, a slable eleclronic siluolion exists for eilher ten or twelve eleclrons in the s-molecular orbitals composed of the nine p ( a ) valence orbitals. We are now carrying o u t a complete molecular orbital analysis of these systems.
DEPARTMENT OF CHEMISTRY COLUMBIA UNIVERSITY NEWYORK27, NEWYORK RECEIVED APRIL 23, 1963
HARRY B. GRAY E. BILLIG
An Unusual Boron Exchange Reaction' Sir: We wish t o report an unprecedented type of exchange reaction involving complete isotopic substitution in a Blo framework. Previous studies of exchange and interconversion processes in boron hydrides and boron hydride ions containing ten or more boron atoms have concentrated almost exclusively2 on exchange and tracer experiments using deuterium. Deuterated decaboranes have been prepared specifically labeled in a variety of positions by exchange of (1) Interconversion of Boranes. V I I . For paper V I of this series see D. F. Gaines, R. Schaeffer and F. Tebhe, I n o r g . Chem., 2 , 526 (1963). (2) Absence of boron exchange between LOB labeled diborane, 'OBzHa, and normal decaborane, BloHu, has been demonstrated: I. Shapiro and R . E. Williams, J . A m . Chem. Sac., 81, 4787 (1959).
Vol. 85
decaborane with d i b ~ r a n e - d ~deuterium ,~ ~ x i d e , or ~!~ deuterium chloride,8and by reaction of the monosodium salt of decaborane, NaBloH13, with deuterium ~ h l o r i d e . ~ Although within the limits of these experiments decaborane and the closely related salt NaBloHl~have appeared immune t o framework disruptions, the initial results in the present study of skeletal rearrangements in the higher boron hydrides indicate that diborane undergoes complete boron interchange with NaBloHla in ethereal solution. A sample of NaBloH13was prepared4,' by reaction of decaborane (0.778 mmole) of normal (20% log) isotopic content with sodium hydride in diethyl ether solution. Hydrogen evolution according t o the equation BloH14
+ NaH -+NaB10Hla + Hz
(1)
was complete (97.3% of calculated) within 25 min. a t room temperature. The solution was filtered under vacuum t o give a pale yellow filtrate. Diborane, 96.470 O ' B (4.58 mmoles), was condensed into the flask ' and shaken for and the coiitents were warmed t o 0 1 hr., during which time no hydrogen formed. By mass spectrometric analysis the loB content of the recovered diborane was shown t o have decreased t o 62.7%, in close agreement with the value calculated (61.9% log, taking into account the incomplete hydrogen evolution for (1)) for diborane exchange with all ten borons of the NaBloH13. Boron-10 enriched decaborane was recovered by treatment of the solution with hydrogen c h l ~ r i d eaccording ~~~ t o the equation NaBloHlt
+ HC1+
BloHIA
+ NaCl
(2)
With suitable recorder amplitude variation, the llB n.m.r. spectrum of the loB enriched decaborane w;bs nearly coincident with an isotopically normal decaborane spectrum, in agreement with the mass spectral determination of participation of all boron positions. Although the NaBloH13structure has not been determined, it is probable, from the n.m.r. spectrums and the ready interconversion of decaborane and the salt by (1) and (2) (presumably involving primary removal and replacement of a bridge proton4), t h a t the boron skeleton is similar t o that of decaborane. With the implication that, in the absence of diborane, the boron framework of NaBloH13 undergoes neither dissociative nor internal rearrangement,4 i t therefore seems more probable that in loBexchange the borane-lOB (lOBH3) adds to the normal BIOH13-, forming an exchange intermediate of over-all composition BllH16-, capable of losing an isotopically normal borane to regenerate B10H13- containing the labeled boron in a position different from that originally occupied by the leaving boron. Considering only the boron framework, a model meeting these requirements can be formed by adding a boron t o a decaborane-like cage between the 5 and 10 positions9 t o produce an icosahedral fragment with 11 of the 12 positions occupied, similar to the boron structure proposed10 for the known" BllH14- ion. If the labeled boron is capable of losing its identity among the five top borons, perhaps by tautomerism of the ten (3) J . J. Kaufman and W. S. Koski, i b i d . , 78, 5774 (1956). (4) J . J. Miller and M. F. Hawthorne, ibid., 81, 4501 (1959). (5) I. Shapiro, M. Lustig and R. E. Williams, i b i d . , 81, 838 (1959). (6) (a) M . F. Hawthorne and J. J. Miller, ibid., 80, 754 (1958); (h) J. A. Dupont and M. F. Hawthorne, i b i d . , 8 4 , 1804 (1962). (7) W. V. Hough and L. J. Edwards, Abstracts of Papers, 133rd Kational Meeting of t h e American Chemical Society, San Francisco, Calif., 1958, P. 28-L. (8) P;.J. Blay, K. J. Pace and R. I.. Williams, J . Chem. SOL.,3416 (1962). (9) T h e numbering system used is reproduced in ref. 5 . (10) E. B. Moore, L. L. Lohr and W. N. Lipscomb, J . Chem. P h y s . , 36, 1329 (1961). (11) V. D. Aftandilian, H . C. Miller, G. W. Parshall and E. L. Muetterties, Inorg. Chem., 1, 734 (1962).
July 5, 1963
2021
COMMUNICATIONS TO THE EDITOR
associated hydrogen^,'^^^^ there is, in the absence of an appreciable isotope effect, equal probability of loss of any of the top five borons as borane groups. After removal of one normal borane the labeled boron could be found in a 6(9) or 5(7,8,10) position in the resulting B10H13- fragment, and, after a second exchange, the label, if it remained in the molecule, could be found in any position. As yet there is no evidence for the existence of an isolable BllHla- salt but the model is useful in rationalizing this most unusual exchange reaction. Irrespective of the precise mechanism of exchange, the fact that boron randomization occurs implies that interpretation of the results of isotopic tracer studies will have t o be made with caution in this and related boron hydride systems. Acknowledgments.-This work was supported by National Science Foundation Grant G-14595. We acknowledge the useful discussions of this work with Donald F. Gaines.
non-condensable gas formed gave 32.5 cc. (1.45 mmoles) of carbon monoxide and 3.25 cc. (0.145 mmole) of hydrogen. On the basis of a composition HzGe[Mn(CO)5]2 the volumes of carbon monoxide and hydrogen expected were 34.0 and 3.4 cc., respectively. The proton n.m.r. spectrum (60 Mc.) of bis-(pentacarbonylmanganese) -germane in chloroform shows a single absorption a t 6.67 r . Proton resonances in germanes have been observed a t 6.6-6.9 T . ~Under high resolution, the infrared spectrum of the new germanium-manganese compound (cyclohexane solution) shows a Ge-H stretching band a t 2083 (s) cm.-', and carbonyl bands a t 2016 (vs), 2008 (s) and 1992 (s) an.-'. Additional bands occur a t 654 (s), 645 (s) and 633 (m) crn.-'. Bis-(pentacarbony1manganese)-germane has been stored for months in air without apparent decomposition. I t is also formed, but in small amount, by heating dimanganese decacarbonyl with germane a t 140', but the desired product is difficult t o recover (12) From M.O. arguments it is not desirable t o propose full 5-fold symfrom unreacted manganese carbonyl, and the gas metry for both boron and hydrogen positions in a diamagnetic model of this form, a s pointed out by W. N. Lipscomb (private communication). T h u s non-condensable a t - 196' contains appreciable quana static form of t h e BuHls- model may be constructed with t h e 5 hydrogens tities of carbon monoxide. No manganese pentain excess of 1 per boron distributed among both bridging and -BHa positions carbonyl-substituted germanes were recovered from around t h e open t o p of t h e molecule. reactions between germane or potassium germy1 and (13) Hydrogen tautomerism in boron hydrides has been discussed by R. E. Williams, J . Inorg. Nucl. Chem., 20, 198 (1061). manganese pentacarbonyl chloride or bromide. Apparently the reaction between germane and manCONTRIBUTION No. 1113 RILEYSCHAEFFER DEPARTMENT OF CHEMISTRY FREDTEBBE ganese pentacarbonyl hydride does not proceed via a INDIANA UNIVERSITY simple substitution mechanism BLOOMINGTON, INDIANA GeH4 nHMn( C0)s + GeH4-.[ Mn( CO),] ,, nHz RECEIVED MAY16, 1963 since we have been unable t o detect even a trace of H3GeMn(C0)5 or HGe [Mn(CO)5]3among the products. Chemistry of the Metal Carbonyls. XXIV. Perhaps the first stage of the reaction is reduction, by the manganese pentacarbonyl hydride, of germane t o Bis-(pentacarbony1manganese)-germanelr2 GeH2, followed by addition of two manganese pentaSir : carbonyl groups. Some support for this idea comes We wish t o report air-stable bis-(pentacarbonylmanfrom preliminary observations on the effect of manganese) -germane. This unusual compound was obganese pentacarbonyl hydride on silane. Reaction is tained by a new type of reaction involving treatment of slow and appears t o follow a different course from that a transition metal hydride with a volatile hydride of a involving germane, forming very air-sensitive colored main group element. solids and manganese carbonyl. It is well known t h a t In a typical preparation 630 mg. (3.23 mmoles) of the Si(I1) state is not as easily attained as the Ge(I1) manganese pentacarbonyl hydride3 and 102.5 cc. state. (4.57 mmoles) of germane4 were sealed under vacuum Acknowledgment.-We wish to thank the Gerwith 390 mg. (3.19 mmoles) of tetrahydrofuran in a manium Research Committee for a gift of germanium 100-cc. Pyrex bulb. After 8 days a t room temperature dioxide. (15") the reaction vessel was opened t o the vacuum system and hydrogen (64.8 cc., 2.89 mmoles) containing (6) J. E. Drake and W.L. Jolly, J . Chem. Soc., 2807 (1962). a trace of carbon monoxide was removed with a Toepler DEPARTMENT OF CHEMISTRY A. G. MASSEY pump. Fractionation of the condensable gases showed A . J. PARK QUEENMARYCOLLEGE F. G. A. STONE that 1.61 mmoles of germane and 2.72 mmoles of manUNIVERSITY OF LONDON E. l., ENGLAND LONDON, ganese pentacarbonyl hydride had reacted. SublimaRECEIVED MAY13, 1963 mm.) of the crystals remaining in the tion (80' a t reaction vessel afforded 600 mg. (95% yield based on Mn(C0)gH consumed) of very pale yellow HzGe[MnElectron-Donor Properties of Zinc Phthalocyanine (C0)5Ir (m.p. 87-88'), moderately soluble in organic Sir : solvents. Analytical samples from this and other I t has been shown that electron transfer from preparations were obtained by additional sublimations. phthalocyanine, in the ground and excited states, to .4nd Calcd. for CloHzOloGeMnz: C, 25.8; H, 0.4; chloranil is an efficient mechanism of charge carrier Mn, 23.6; mol. wt., 465. Found: C, 25.5, 25.5, production in semiconducting films. Such processes 26.6; H , 0.3, 0.2, 0.4; Mn, 23.1; mol. ~ t . , ~ 4 7 4 . also have considerable biological importance. Recent A sample (70.6 mg., 0.152 mmole) of bis-(pentastudies of the luminescence and associated properties of carbony1manganese)-germane was heated a t 180' (8 phthalocyanines in this Laboratory appear to demonhr.) with iodine (2 g.). Combustion analysis of the strate analogous electron-donor tendencies in fluid (1) P a r t XXIII: P . M. Treichel, M. A. Chaudhari a n d F. G. A . Stone, solution. J . Ovgonometallic Chem., in press; p a r t XXII: D. W. McBride, S. L. StafI t was found that the absorption band of zinc phthaloford and F.G. A. Stone, J. Chem. Soc., 723 (1963). cyanine a t 668 mp is depressed and broadened in the (2) T h e research reported herein has been sponsqred by t h e U. S.Department of t h e Army, through its European Research Office. presence of the strong acceptors (ie., Lewis acids)
+
(3) (a) W. Hieber and G. Wagner, Z . Nalurforsch., 13b,338 (1958);
+
(b)
I
