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Optical Activity at an Asymmetrical Manganese Atom.

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Corresponding to the difference in the covalent radii, the
bond lengths are about 0.02 - 0.03 A shorter than those in
similarly bonded rhenium compounds: the Tc-0 bridge bonds
(1.840 i 0.001 A) are comparable to the ReIV-O and
RuIV-O bonds in the symmetrical linear bridges of
[Cl5Re-0-ReCl5]4- (1.86 A) [41 and [CI5Ru-O-RuCls]4(1.80 A)[5l. The average value for the lengths of the terminal
T c - 0 bonds (1.673 A; c for a single value 0.006 A) corresponds to the Re-0 distances in the tetrahedra of ReO3CI
(1.702 A) [61, Re207 (1.70 A) [I], and Re207(OH2)2 (1.73 A) 171.
Angular distortion of the O-Tc03 tetrahedra is only slight;
the bond angles vary between 107.8 and 110.9 '. It has not yet
been possible t o elucidate completely the nature of the crystalline red phase of probable composition Tc207 . H20 in
the system ditechnetium heptoxide-water.
Received: January 8, 1969
[Z 958 IE1
German version: Angew. Chem. 8/,328 (1969)
[*I Dr. B. Krebs
Anorganisch-Chemisches Institut der Universitat
34 Gottingen, Hospitalstr. 8-9 (Germany)
[l] B. Krebs, A. Miiller, and H. Beyer, Chem. Commun. 1968,
263; Inorg. Chem. 8, 436 (1969); B. Krebs, Habilitationsschrift,
Universitat Gottingen 1968.
[ 2 ] G. E. Boyd, J . W. Cobble, C . M. Nelson, and W. T . Smith, J.
Amer. chem. SOC.74, 556 (1952); W. T . Smith, J . W. Cobble, and
G . E . Boyd, ibid. 75, 5773 (1953).
[3] B. Krebs and A . Miiller, 2. Naturforsch. 236, 415 (1968).
141 J . C . Morrow, Acta crystallogr. 15, 851 (1962).
[5] A . McL. Mathieson, D . P . Mellor, and N . C . Stephenson, Acta
crystallogr. 5 , 185 (1952).
[6] E. Amble, S.L . Miller, A . L . Schawlow, and C . H . Townes, J.
chem. Physics 20, 192 (1952); J. F. Lotspeich, A. Javan, and A.
Engelbrecht, ibid. 31, 633 (1959).
[7] H. Beyer, 0. Glemser, and B. Krebs, Angew. Chem. 80, 286
(1968); Angew. Chem. internat. Edit. 7, 295 (1968).
[ 8 ] T . Ueki, A . Zalkin, and D . H . Templeton, Acta crystallogr.
19, 157 (1965).
Preparation of Pure 2nd and 3rd Phase
Graphite-Iron(I11) Chloride Inclusion Compounds
and of Graphite-Iron(I11)
Bromide Inclusion Compounds
The third phase, with 34-40% FeCI3, is formed at TI =
410-420°C, Tz = 300'C. In the Debyeogram the weak reflections 002 and 004 of the graphite occur in addition to the
basal reflections 002, 003, 004, 005, 006, 007. 009, 0010, 0011
with d = (9.38 2 x 3.35) = 16.08 A.
Iron(n) bromide, bromine, and graphite undergo reaction in a
bomb tube t o give graphite-FeBr3 inclusion compounds. At a
reaction temperature of 100 "C theincluded FeBr3 can amount
t o 55 wt-% (after washing). If the lattice dimensions of the
FeBr3 in the layer planes, like those of the FeC13, do not alter
during the inclusion reaction this FeBr3 content corresponds
analytically t o a compound of the second phase. The observed X-ray reflections, however, have not as yet been interpreted.
+
Received: January 27, 1969
IZ 964 IE]
German version: Angew. Chem. 81, 333 (1969)
[*I D. Hohlwein, Dr. F. D. Grigutsch, and
Prof. Dr. A. Knappwost
Institut fur Physikalische Chemie der Universitat
2 Hamburg 36, Jungiusstrasse 9 (Germany)
[l] J. G. Hooley and M . Bartlett, Carbon 5,417 (1967)
[2] A. Knappwost and F. D . Grigutsch, unpublished.
Optical Activity at an Asymmetrical Manganese
Atom
By H. Brunner [*I
The compounds [C~HsMn(CO)(NO)P(CsH~)~l+[PF61-[~]
(I)
and [C5HsMn(COOCH3)(NO)P(C6H5)3]111, which is prepared from ( I ) by methoxide addition, contain four different
substituents attached to a central manganese atom. Since
these complexes have pseudotetrahedral structures enantiomeric pairs must exist. The diastereomers occurring o n introduction of a n optically active agent into the molecule ought
t o be separable from each other, provided that the configurations are sufficiently stable.
Addition of the optically active L-mentholate anion (2)t o the
carbonyl group of the D,L mixture (1a.b) leads to the formation of the D, L-L derivative ( 3 a , b ) . T h e I R spectrum (KBr) of
the red crystalline product contains, in addition to the bands
of cyclopentadienyl-. triphenylphosphine-, and menthyl residues, the NO stretching vibration at 1724 cm-1 and the absorption of the C O double bond at 1616 cm-1.
By D . Hohlwein, F. D. Grigutsch. and A . Knappwost [*I
From the results of sorption measurements carried out by
Hooley and Bartlett[lI we have developed a process for the
preparation of graphite-FeC13 inclusion compounds in definite phases. Anhydrous FeCI3 and graphite (in the ratio 5:1
by weight) are placed without mixing in opposite ends of a
bomb tube. The tube is evacuated and, by using two ovens,
each end is heated to a different but definite temperature. The
graphite is heated to a higher temperature than that of the
pure FeC13, so that a thermodynamic equilibrium can be set
up between included and pure FeC13. On completion of reaction the equilibrium composition of the product is "frozen
in" by quenching.
The disadvantage mentioned by us 121 regarding the methods
of preparation previously adopted, i.e. formation of higher
(metal-halide deficient) phases by subliming off metal halide
without reaching thermodynamic equilibrium between inclusion compound and sublimate, does not occur in this
process.
The difference in solubility between the two diastereomers
( 3 a ) and ( 3 6 ) is so great that they can easily be separated
from each other; the dextrorotatory isomer ( 3 a ) dissolves in
pentane, whereas the levorotatory isomer ( 3 6 ) is sparingly
soluble in aliphatic hydrocarbons.
In accord with the 35OoC isothermt'l, a pure second phase
with 48-51 wt- % FeCI3 (after washing with 2 N HCl) occurs
at TI (temperature of graphite) = 350 O C and T2 (temperature
of FeCls) = 300OC. The Debyeogram shows the basal
reflections of the second phase with d = (9.38
3.35) =
12.73 8,002, 003, 004, 007, and 008 and, with lesser intensity,
the graphite reflections 002 and 004. Because of the pronounced texture further reflections are not observable.
+
382
Angew. Chem. internat. Edit.
1 Vol. 8 (1959) 1 No. 5
The highspecificrotationsofbothformsslowly decreasein benzene solution and reach an equilibrium value of [ E ] $ ~= +lo5
which is to be ascribed to the remaining optical activity ofthe
menthyl group after racemization a t the manganese atom.
The diastereomers (3a) and (3b) are configurationally stable
in the solid state. On prolonged heating in pentane ( 3 a ) is
converted into the difficultly soluble ( 3 b ) ;conversion of ( 3 b )
into the more easily soluble diastereomer ( 3 a ) is possible by
extraction from the equilibrium mixture with pentane.
All the stable complexes are paramagnetic with p w 1.75 BM.
The UV-absorptions of ca. 4000 and 6050 A for the brown
anions and the blue anions agree with the values given in the
literature [I].
Table 1. Stretching vibrations (cm-1) of the complexes (1)-(6).
FNO Ial
(I).2H20
1935
2142-2170
161
1746
1741
1742
2100; 2110 sh
2110;2120sh
2103; 2110 sh
Experimenial:
To 3.75 g (6.4 mmoles) of compound ( I ) [11 at 0 "C is added a
solution of Na-mentholate (2) [prepared from lg (6.4 mmoles)
(-)-menthol and excess of sodium] in 30 ml of tetrahydrofuran saturated with N2. The deep-red reaction mixture is
evaporated and the residue is dissolved in 50 ml of benzene.
The red benzene solution is filtered over anhydrous Na2S04
and concentrated. Pentane is added to the concentrated
benzene solution and the precipitate thus obtained is
isolated and extracted with pentane until the eluate is colorless. The extract contains 1.5 g (40 %) of the dextrorotatory
diastereomer (3a ) which separates out partially racemized.
The residue from the extraction contains 1.3 g (35 %) of the
= -450'
(c = 0.1
levorotatory diastereomer ( 3 b ) . [or]:&
silo0 ml; benzene). If pentane is added to the extracted product - which, depending on the conditions, is more or less
dextrorotatory - and the mixture is filtered so that the filtrate
drops into a receiver cooled to -5OoC, pure ( 3 u ) , [a]:& =
+460 "C (c = 0.1 g/lOO ml benzene) separates out.
Received: February 4, 1969
[Z 966 IE]
German version: Angew. Chem. 81, 395 (1969)
[*I Dr. H. Brunner
Anorganisch-ChemischesLaboratorium
der Technischen Hochschule
8 Miinchen 2, Arcisstr. 21 (Germany)
[I] H . Brunner, Z . anorg. allg. Chem., in press.
Stable Salts Containing the Unusual Anions
[Fe(CN)5N0]3- and [Fe(CN)sNOH]ZBy R . Nast and J. Schmidt [*I
"0
Ibl
2.2
1.6
1.6
(KBr)
(nujol
(nujol)
(nujol)
(HICCN)
(nujol)
13.4
1.8
13.4
1.8
13.4
1.8
[a] FNO (mdynes/A):VFF force constants in -NOH
sideration of the proton.
without con-
[b] "0: bond order according to H . Sieberf.
The decrease of about 0.6 in the NO bond order on going
from [Fe(CN)sN0]2- to [Fe(CN)sN0]3- supports the concept of Munoharan and Gruy[21, according to which an e*
orbital having predominant &J character is occupied in the
reduction. It seems to us that the increase in bond order of cu.
0.2 on protonation is understandable only if a strong contribution of the H l s orbital to the unpaired e* (xko, electron of
the complex is assumed. This view is further supported by
the difference (observed by us and by van Voorst and Hemmerich [I]) between the ESR spectra of the blue and the brown
anions. Accordingly, the proton must be bound to the NO
group with participation of the unpaired electron in a type of
bonding which has yet to be elucidated. The existence of a
FeCNH grouping can be excluded on the basis of the IR
spectra and chemical reactions.
To regard [Fe(CN)sNOH]Z- as a Brmsted acid having a
pKa value of 6.5 [I] appears to us to be unjustified since the
precipitation of [Ph4X]z[Fe(CN)5NOH]from liquid ammonia
at the high basicity of the solvent cannot then be explained.
Participation of the unpaired electron in the protonation is
plausible since no protonation at the NO has hitherto been
observed in any NO+ complex.
Further reduction of [Fe(CN)sN0]3- yields [Fe(CN)4N0]3and [Fe(CN)3N0]4- r3J.
Received: February 28, 1969
12 971 IE]
German version: Angew. Chem. 81, 399 (1969)
Publication delayed at authors' request
The previously postulated anions [Fe(CN)sN0]3- and
[Fe(CN)5NOH]2- [I] can be prepared by reduction of
N a ~ [ F e ( c N ) ~ N o( lI ) with sodium in liquid ammonia. We
have succeeded in preparing for the first time the ocher-yellow
compound trisodium pentacyanonitrosylferrate-2-ammonia,
N a ~ [ F e ( c N ) ~ N o.l 2NH3 ( 2 ) , which is sparingly soluble
at -7OOC and is sensitive to air. At temperatures above
-3OoC, compound (2) disproportionates - as can be
followed IR spectroscopically - according to the following
scheme:
+ [Fe(CN)4N0]3- + CN-
2 [Fe(CN)sNO],- + [Fe(CN)sNO]*-
On addition of [Et4N]Cl (Et = CzH5) to the brown solution
of this compound in liquid ammonia at - 40 OC, gold-brown
crystals of [Et4N]3[Fe(CN)sNO] ( 3 ) precipitate which are
stable at room temperature. With [Ph4XICl (Ph = C&),
however, we obtained blue stable compounds of the composition [Ph4X]2[Fe(CN)sNOH] ((5): X = P; ( 6 ) : X = As). In
proton active organic solvents such as acetonitrile, ( 3 ) is also
present in the temperature-dependent equilibrium.
[*J Prof. Dr. R. Nast und Dr. J. Schmidt
Institut fur Anorganische Chemie der Universitat
2 Hamburg 13, Papendamm 6 (Germany)
[l] J . D. W. van Voorsr and P. Hemmerich, J. chem. Physics 45,
3914 (1966); see also R . G. Hayes, ibid. 48, 4806 (1968).
[2] P. T.Manoharan and H. B. Gray, J. Amer. chem. SOC.87,
3340 (1965).
[3] R . Nast and J. Schmidt, unpublished.
Synthesis of Pyrimido[4,5-dlpyrimidine
By H . Bredereck, G . Simchen, and M . Kramer [*I
PyrimidoI4.5-dIpyrimidine (2) is a theoretically interesting
compound because of the anellation of two n-electron deficient systems; however, attempts to prepare it or its derivatives bearing substituents in position 2 from 4-aminopyrimidine-5-carbaldehyde[I 921 by condensation with formamidine, acetamidine 131, and benzamidine 131, and with formamidinium acetate, have failed since the water formed during
[E4N13[Fe(CN)sNOl+ H+ + [Et4N]2[Fe(CN)5NOH]+ [Et4N]+
(3)
(41
After addition of acetic acid, the blue stable salt ( 4 ) can be
precipitated with ether.
Angew. Chem. internat. Edit. I Vol. 8 (1969) I No.5
383
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