1386
Inorg. Chem. 1996, 35, 1386-1388
Synthesis and Molecular Structure of a Novel
Monocarbon Hydridorhodacarborane:
Scheme 1
closo-2,7-(PPh ) -2-H-2-Cl-1-(NMe )-2,1-RhCB H
3
2
3
10
9
,
†,1a
Irina V. Pisareva,†
Igor T. Chizhevsky,*
†
†
Pavel V. Petrovskii, Vladimir I. Bregadze,
†
†
Fedor M. Dolgushin, Alexandr I. Yanovsky,
†
,‡,1b
Yuri T. Struchkov, and M. Frederick Hawthorne*
Institute of Organoelement Compounds, Russian Academy of
Sciences, Vavilova Str. 28, 117813 Moscow, Russia, and
Department of Chemistry and Biochemistry,
deduced from spectroscopic and analytical data. The 31P{ H}
1
NMR spectrum of 4 exhibited one doublet at 37.3 ppm with
JP-Rh ) 152 Hz due to the PPh3 group attached to rhodium.
Both the chemical shift and coupling constant values associated
with this signal proved to be very similar to those observed in
University of California, Los Angeles, California 90095
ReceiVed August 2, 1995
3
1
1
the P{ H} NMR spectra of the previously described 16-
electron Rh(III) mononuclear monocarbon closo-rhodacarbo-
Introduction
6
1
ranes. The H NMR spectrum of 4 revealed phenyl multiplets
centered at 7.45 ppm as well as a singlet at 3.69 ppm, as
expected for equivalent methyl groups in the N(CH3)3 cage
substituent. The latter complex was obtained in reasonable yield
when the reaction was terminated and the products were isolated
Since the first demonstration of the exceptional efficacy of
hydridometallacarboranes derived from the 7,8- and 7,9-isomers
of nido-C2B9H112 as homogeneous catalyst precursors, sig-
-
2
nificant advances have been achieved in the development of
their unique chemistry.3 In addition, many related hydrido-
7
after 3.5 h. The latter observation suggests 4 as one of the
metallacarboranes of the platinum group metals based upon a
3c,4
possible intermediates leading to the formation of 3.
variety of carborane derivatives have been obtained.
We here
Complex 3 was obtained as an air-stable crystalline material,
and its structure was elucidated as described below. The
report the synthesis and single-crystal X-ray diffraction study
of a novel monocarbon hydridometallacarborane derived from
nido-B10H12CNMe3 (1), viz. closo-2,7-(PPh3)2-2-H-2-Cl-1-
3
1
1
P{ H} NMR spectrum of 3 in CH2Cl2 contained two reso-
nances, a sharp doublet (δPa ) 26.2 ppm, JP-Rh ) 104.5 Hz)
and a broadened signal (δPb ) 11.0 ppm, JP-B ≈ 120 Hz) which
resembled a quadruplet. These resonances were attributed to
PPh3 groups at rhodium and boron atoms, respectively. This
(
NMe3)-2,1-RhCB10H9 (3), which is the first structurally
characterized mononuclear hydride complex with an icosahedral
monocarbon carborane ligand.
1
1
1
Results and Discussion
was confirmed by the B{ H} NMR spectrum of 3 which
revealed a unique sharp doublet at -7.8 ppm (JB-P ≈ 127 Hz)
originating from the boron atom substituted by a PPh3 group
within a set of broad resonances derived from the BH vertices
5
The reaction of 1 with 1 molar equiv of Rh(PPh3)3Cl (2) in
hot methanol produced 3 as a yellow precipitate in 72% yield,
together with a small amount of a 16-electron rhodacarborane,
closo-2-(PPh3)-2-Cl-1-(NMe3)-2,1-RhCB10H10 (4), which was
isolated from the reduced mother liquor by column chroma-
tography on silica gel (Scheme 1). The structure of 4 was
1
of the carborane cage. The H NMR spectrum of 3 in CD2Cl2
exhibited complex overlapping multiplets originating from both
of the PPh3 groups, a singlet at 2.92 ppm from equivalent methyl
groups at the N(CH3)3 substituent, and a doublet of doublets of
doublets at -9.63 ppm due to the terminal hydride at the
rhodium atom. The multiplicity of the hydride resonance
observed is consistent with the coupling of hydrogen to two
†
Russian Academy of Sciences.
University of California at Los Angeles.
‡
(
1) (a) To whom correspondence from the former Soviet Union should
be directed. (b) To whom other correspondence should be directed.
2) (a) Paxson, T. E.; Hawthorne, M. F. J Am. Chem. Soc. 1974, 96, 4674.
31
31
103
nonequivalent PPh3 groups ( Pa and Pb) and a Rh nucleus.
(
3
1
Selective decoupling of Pb nuclei caused a collapse of the
(b) Belmont, J. A.; Soto, J.; King, R. E., III; Donaldson, A. J.; Hewes,
J. D.; Hawthorne, M. F. J. Am. Chem. Soc. 1989, 111, 7475 and
references therein.
3) (a) Kalb, W. C.; Demidowicz, Z.; Speckman, D. M.; Knobler, C. B.;
Teller, R. G.; Hawthorne, M. F. Inorg. Chem. 1982, 21, 4027. (b)
Long, J. A.; Marder, T. B.; Hawthorne, M. F. J. Am. Chem. Soc. 1984,
hydride signal to a doublet of doublets with JH-Rh ) 11.0 Hz
31
and JH-Pa ) 46 Hz. The small coupling constant of the Pb
(
(
(
nucleus with the hydride at the Rh center (JH-P ≈ 7 Hz) was
1
31
elucidated from a second decoupling H{ Pa} NMR experiment
and gave additional confirmation of the nature of this PPh3
group.
106, 3004. (c) Doi, J. A.; Mizusawa, E. A.; Knobler, C. B.; Hawthorne,
M. F. Inorg. Chem. 1984, 23, 1482. (d) Long, J. A.; Marder, T. B.;
Behnken, P. E.; Hawthorne, M. F. J. Am. Chem. Soc. 1984, 106, 2979.
The solid state structure of complex 3 was determined by an
X-ray diffraction study which proved this species to be a closo-
hydridorhodacarborane (Figure 1) with quaternary nitrogen and
phosphorus groups attached to a monocarbon carborane ligand
(
1
e) Walker, J. A.; Knobler, C. B.; Hawthorne, M. F. Inorg. Chem.
985, 24, 2688. (g) Zakharkin, L. I.; Chizhevsky, I. T.; Zhigareva, G.
G.; Petrovskii, P. V.; Polyakov, A. V.; Yanovsky, A. I.; Struchkov,
Yu. T. J. Organomet. Chem. 1988, 358, 449. (f) Chizhevsky, I. T.
Metalloorg. Khim. 1991, 4, 1416.
4) (a) Wong, E. H. S.; Hawthorne, M. F. Inorg. Chem. 1978, 17, 2863.
(b) Hewes, J. D.; Knobler, C. B.; Hawthorne, M. F. J. Chem. Soc.,
(6) Chizhevsky, I. T.; Pisareva, I. V.; Petrovskii, P. V.; Bregadze, V. I.;
Yanovsky, A. I.; Struchkov, Yu. T.; Knobler, C. B.; Hawthorne, M.
F. Inorg. Chem. 1993, 32, 3393.
Chem. Commun. 1981, 206. (c) Busby, D. C.; Hawthorne, M. F. Inorg.
Chem. 1982, 21, 4101. (d) Delaney, M. S.; Knobler, C. B.; Hawthorne,
M. F. Inorg. Chem. 1981, 20, 1341. (e) Walker, J. A.; O’Con, C. A.;
Zheng, L.; Knobler, C. B.; Hawthorne, M. F. J. Chem. Soc., Chem.
Commun. 1983, 803. (g) Hewes, J. D.; Thompson, M.; Hawthorne,
M. F. Organometallics 1985, 4, 13. (f) Alcock, N. W.; Taylor, J. G.;
Wallbridge, M. G. H. J. Chem. Soc., Dalton Trans. 1987, 1805. (h)
Nestor, K.; Fontaine, X. L. R.; Greenwood, N. N.; Kennedy, J. D.;
Plecek, J.; Stibr, B.; Thornton-Pett, M. Inorg. Chem. 1989, 28, 2219.
5) Knoth, W. H.; Little, J. L.; Lawrence, J. R.; Scholer, F. R.; Todd, L.
J. Inorg. Synth. 1968, 11, 35.
(7) In this case another new crystalline product was isolated from the
reaction mixture by the procedure given in the Experimental Section.
Although this compound was not available in sufficient quantities to
allow complete characterization from spectroscopic data, it was
concluded that the species can be regarded as a 12-vertex monocarbon
rhodacarborane with PPh3 (δP ) 30.9 ppm, JP-Rh ) 164.2 Hz in CD2-
Cl2) and NMe3 (δH ) 3.49 ppm in CD2Cl2) ligands at the rhodium
and at the carbon cage atoms, respectively. No other attempts, however,
were made to characterize this compound.
0
020-1669/96/1335-1386$12.00/0 © 1996 American Chemical Society
Chizhevsky, Igor T.
