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Imidophosphinatotin Halides.

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contribute to delocalization of the unpaired electron, or
by their space-filling reduce the chemical reactivity at C2,
are particularly effective in prolonging the life. When R 2 or
R3 = H n o anion radical was observed.
Table 1 shows the properties of the new nitroalkenes ( I ) ,
together with the nitrogen and proton coupling constants
U N and aH, respectively, of the radicals (2) that could be
unambiguously assigned. Fig. 1 illustrates a particularly
simple ESR spectrum.
8.76
c
?
)
Fig. 1. ESR spectrum of the anion radical from 2methyl-l-nitro-2-tbutylethylene (Zf), and the line spectral diagram.
culations 11 gauss and 6-7 gauss, respectively, are to be
expected for these anion radicals. ON values of ca. 24 gauss
are characteristic of anion radicals from aliphatic nitro
compoundsrg]. The existence of radicals of this structure is
also indicated by the number of proton coupling constants
that has been givenIzl for the radicals from 2-nitropropene
and o-nitrostyrene.
Received: January 2nd, 1967
[ Z 418 IEl
German version: Angew. Chem. 79, 240 (1967)
[*] Dr. A. Berndt
Institut fur Organische Chemie der Universitat
Bahnhofstr. 7
335 Marburg (Germany)
[l] K . Tsuji, H . Yamaoka, K. Hayushi, H . Kamiyama, and H . Yoshida, J. Polymer Sci. B 4, 629 (1966).
[2] I. A . Prokof’ev, V. M . Chibrikin, 0. A.Yuzhakova, and R. G.
Kostyanovsky, Izvest. Akad. Nauk SSSR, Ser. chim. 1966, 1105;
Chem. Abstr. 65, 12084c (1966).
[3] Polarographic measurements by Dr. F. Steuber, Marburg.
[4] Short paper, EUCHEM Conference on “Organic Radicals”,
October 24 to 28, 1966, Schloss Elmau/Oberbayern.
[5] A. D . McLachlan, Molecular Physics 3, 233 (1960).
[61 P. H . Rieger and G. K . Fraenkel, J. chem. Physics 39, 609
(1963).
[7] In collaboration with Dr. A. Schweig, Marburg, at the
Deutsche Rechenzentrum, Darmstadt.
[S] L. H. Piette, P. Ludwig, and R . N. Adams, J. Amer. chern.
SOC.84, 4221 (1962).
Table 1. Properties ofnitroalkenes ( I ) and radicals (2).
(1)
R’
Rz
R3
M.P. (“C)
or b.p.
(“C/mm)
85
56
(72/0.05)
(93/0.14)
(99/20)
149
(2)
By A . Schmidpeter and K . StoN[*J
ON
aH(R1) aH(R3 = CH3)
6.0
-
-
6.3
7.0
3.2
3.5
- [a1
7.9
10.4
11.9
11.6
2.8
3.0
3.5
3.2
9.3
8.7
9.0
-
-
2.8
behave as univalent bidentate ligands toward transition
metals 12931and toward main group elements [41 of coordination
number 6 ; in the latter case a larger variety of typeslof
compounds are formed.
-
L
[a1 Coupling constants (in gauss) of the phenyl protons: .a and ap
1.2; am = 0.6.
(3),
=
[bl Stable radicals are also obtained from 9-nitromethylenefluorene
(R1 = H, RZ
R3 = biphenylylene) and 9-(a-nitrobenzylidene)fluorene
(R’ = C ~ H SRz
, iR3 = biphenylylene), m.p. 123 ‘C. Their ESR spectra
are under study.
+
-HBnX,
It
(41,
+2HX
r
The spin density distribution was calculated (71 by McLachfun’s method 151 with the parameters for aromatic nitro anion
radicals 161. The nitrogen coupling constants aN were calculated from the resulting spin densities on nitrogen F N and
oxygen PO from equation (a) [61.
a N = (99.0& 10.2) PN - (71.6 & 11.8) po
(a)
The calculated and the experimental coupling constants are
compared in Table 2.
Nitrogen coupling constants of 24.0 and 23.3 gauss have
been given for the reduction products of 2-nitropropene 121
and w-nitrostyrene 121, respectively. According to our cal-
252
1
Rz
(u),
P = d \o-PQ
R2
R2
(5)
Table 2. Experimental and calculated nitrogen coupling constants
aN (in gauss).
z = snxiz = 2 c10,-
x = c1
(b), X = Br
(c),
x
= I
SnC14 or SnBr4 and ((C&&PO)zNH give first adducts ( I ) ,
which yield bis(imid0diphosphinatotin dihalides (2) under
the action of a weak base, e.g. when boiled with water. This
reaction appears to indicate structure (3) for the adduct
which however is not in accord with the Mossbauer spectrum
(only one resonance line with a n isomeric shift that is
distinctly different from that of SnX62-; on the other hand
the shifts come close to those of 2.2’-dipyridyltin(1v) halide
adducts [51).
Angew. Chem. internat. Edit. 1 Vol. 6 (1967) I No. 3
286-292
278-280
(Ib)
I
i
0.40
0.63
342, 330, 304, 170
244, 226,209
[a] Relative to SnOz. - Shifts for SnC1& 0.50 mmisec, for SnBr6Z0.87 mmjsec [51.
In agreement with structure ( I ) the I R spectra contain three
to four absorption bands assignable, very probably, to SnX
vibrations; the presence of the H N group is shown by a band
at 3130 cm-1. The molecular size could not be determined
since ( l a ) and ( I b ) are insoluble in non-solvolysing media,
(20) and (2b) are formed, not only by the solvolytic disproportionation of ( l a ) and ( I b ) , but also by melting ( I n )
or ( I b ) with further ((GjHs)zPO)zNH, from SnX4 and
((C~HS)~PO)~N
and
N ~by
, addition of Clz or Br2 to tin(1r)
bis(tetrapheny1imidodiphosphinate) ( 5 ) .
The Molecules Pd6ClI2and Pt6C11, in the Gaseous
State. A Contribution to the Problem of M6X12
Groups
By H. Schafer, U . Wiese, K . Rinke, and K . Brendel[*I
Palladium(r1) chloride crystallizes in an or-form which,
according to Wells [ I ] , contains endless chains of coplanar
PdC1412 units (m[PdCl4/2]; Fig. la). We have found a @-form
which, according to Guinier photographs, is isotypic with the
modification of platinum(~r)chloride described by Broderson,
Thiele, and von Schnering[21. Thus the Pd6C112 molecules
assume a space-centered arrangementk([PdsC11~];Fig. 1b).
When tempered at 500 "C, this p-form passes into the or-form.
The $-modification [Pd6C112] is formed when either form is
sublimed in a vacuum.
(5) is formed on melting together tin(@ acetate and
((C6H5)2PO)NH in a vacuum. It is soluble and monomolecular in polar organic solvents and aromatic compounds,
and according to its 31P-NMR spectrum it contains only
equivalent phosphorus atoms, so that it is also a chelate.
(2c) is obtained directly from SnI4 and ( ( C & S ) ~ P O ) ~ N H .
The complexes (2) apparently exist in the cis-form; their
dipole moments in dioxane amount to 7 to 8 Debyes. (2c) in
CH2C12 gives two 31P-resonance signals of comparable
intensity.
(5)
M.p. ( "C)
325-327
283-285
8 (3'P)
-28.8
-28.4
(ppm)
yellow,
258-260 (dec.)
-28.0; -26.3
215-217
--17.9
[bl
I n the mass spectrometer both modifications yield Pd6C112
molecules (mean mol. wt. 1064) with high intensity; (PdClz),
6 d o not occur. It is therefore improbable
molecules with n
that the Pd6C112 molecules observed have a chain or ring
structure. Pd6C112 molecules (as in Fig. l b ) apparently occur
in the gas phase, as in the @-modification[ 3 1 .
Particular interest attaches to the ready transition: chain 2
polyhedron. We attribute this to the fact that a Pd6C112
polyhedron can be developed from a [PdC14/2]chain (Fig.lc).
Starting from the end o f the chain, one has only to break
one of t h e four bonds attached to each Pd atom, whereby
the connection through the chain remains but free rotation
becomes possible around each bond. In terms of molecular
kinetics this doubtless occurs by opening of alternate bonds
and reclosure thereof in their new positions. All the bond
angles (Pd-CI-Pd
and CI-Pd-CI) remain unchanged. It
should be emphasized that this is the first reasonable demonstration of the way i n which such M6X12 groups can
be formed.
Evaluation of data in the literature [3,41 gives the following
bond energies for the Pd-CI bond: m[PdC14!2] chain
(rw-PdCI2) 48 kcal; gaseous Pd6C112 46 kcal; gaseous monomeric PdC12 62 kcal. The bond energy for the chain is almost
identical with that for the polyhedron. It is significant that
the first of the four Pd-C bonds of a PdC14.2 unit is more
easily broken than the others and it is for this reason that
the chain is not disrupted in forming the polyhedron.
On vaporization of the platinum(1r) chloride from a preparation that contains a high proportion of the [Pt&112]
modification, the heaviest particles seen in the mass spectrometer are Pt6C112 molecules (mean mol. wt. 1596)[51. However, ions such as Pt4CIt and PtsCllo" (of somewhat lower
intensity than Pt6C112@)are found. This behavior is different
from that of Pd6C112.
If the dsp2-orbitals of the metal atom are used for binding
C1° ions in planar arrangement, the remaining d-orbitals
of the palladium or platinum are fully occupied and are not
available for metal-metal bonding. The existence of Pd&112
+
[bl Measured in CHzCIz; relative to 85 % H3P04;negative values refer to
lower field strengths.
Compounds (2) are cleaved back to ( I ) and ((c6H5)zPo)zNH
by hydrogen halides; anhydrous perchloric acid, however, is
added, yielding (4). Structure ( 4 ) is proved by equivalence
of the phosphorus atoms in the 31P-NMR spectrum, the
appearance of N H bands at 2925 and 2640 cm-1, and solvolytic removal of HC104 by acetonitrile or methanol, to give ( 6 )
or (2), respectively.
The 1R spectra of (4) d o not correspond with those of the
adducts from SnX4 and ( ( C ~ H ~ ) ~ P O ) Z NThis
H . confirms
chemically that the correct formula for the adduct is ( I ) ,
and not (3).
Received: January 12th, 1967
[Z 417 IE]
German version: Angew. Chem. 79, 242 (1967)
-
I*]Dr. A. Schmidpeter and Dip1.-Chem. K. Stoll
Institut fur Anorganische Chemie der Universitat
Meiserstr. 1
8 Munchen 2 (Germany)
[lJ Part 6 of Phosphazenes. - Part 5 : A . Schmidpeter and J . Ebeling, Angew. Chem. 79, 100 (1967); Angew. Chem. internat.
Edit. 6, 87 (1967). - The 31P-NMR spectra were determined by
Dip1.-Chem. H . Brecht. We are grateful to Prof. N.N . Greenwood,
Dr. B. P . Sfraughan and Mr. J. N. R. Ruddick, Newcastle, for
determination of the Mossbauer and IR spectra in the iong-wave
region and for discussions.
[2] A . Schmidpeter, R . Bohm, and H . Groeger, Angew. Chem. 76,
860 (1964); Angew. Chem. internat. Edit. 3, 704 (1964).
131 H. J. Keller and A . Schmidpeter, Z . Naturforsch. 226 (1967),
in press.
[41 Recently diphosphinimide complexes of beryllium ( K . L. Paciorek and R. H . Kratzer, Inorg. Chem. 5 , 538 (1966)) and boron
(H. Nofh, personal communication) have been obtained.
151 N. N . Greenwood, personal communication.
Angew. Chem. internat. Edit.
Vol. 6 (1967)
No. 3
253
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