Chemistry of mangana- and rhenatricarbadecaboranyl tricarbonyl complexes: Evidence for an associative mechanism of ligand substitution involving an η6-η4 cage-slippage process analagous to η5-η3-cyclopentadienyl

Article abstract of DOI:10.1021/ja062201u

The reaction of the tricarbadecaboranyl anion, 6-Ph-nido-5,6,9-C ₃B₇H₉^-, with M(CO)₅Br [M = Mn, Re] or [(η⁶-C₁₀H₈)Mn(CO) ₃⁺]BF₄^-<

Full text of DOI:10.1021/ja062201u

Published on Web 06/14/2006
Chemistry of Mangana- and Rhenatricarbadecaboranyl
Tricarbonyl Complexes: Evidence for an Associative
Mechanism of Ligand Substitution Involving an η6-η4
Cage-Slippage Process Analagous to η5-η3-Cyclopentadienyl
Ring-Slippage
Robert Butterick III, Bhaskar M. Ramachandran, Patrick J. Carroll, and
Larry G. Sneddon*
Contribution from the Department of Chemistry, UniVersity of PennsylVania,
Philadelphia, PennsylVania 19104-6323
Received April 7, 2006; E-mail: lsneddon@sas.upenn.edu
Abstract: The reaction of the tricarbadecaboranyl anion, 6-Ph-nido-5,6,9-C3B7H9-, with M(CO)5Br [M )
Mn, Re] or [(η6-C10H8)Mn(CO)3+]BF4 yielded the half-sandwich metallatricarbadecaboranyl analogues of
-
(η5-C5H5)M(CO)3 [M ) Mn, Re]. For both 1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MC3B7H9 [M ) Mn (2) and Re
(3)], the metal is η6-coordinated to the puckered six-membered open face of the tricarbadecaboranyl cage.
Reactions of 2 and 3 with isocyanide at room temperature produced complexes 8-(CNBut)-8,8,8-(CO)3-
9-Ph-nido-8,7,9,10-MC3B7H9 [M ) Mn (4), Re (5)], having the cage η4-coordinated to the metal. Photolysis
of 4 and 5 then resulted in the loss of CO and the formation of 1-(CNBut)-1,1-(CO)2-2-Ph-closo-1,2,3,4-
MC3B7H9 [M ) Mn, Re (6)], where the cage is again η6-coordinated to the metal. Reaction of 2 and 3 with
1 equiv of phosphine at room temperature produced the η6-coordinated monosubstituted complexes 1,1-
(CO)2-1-P(CH3)3-2-Ph-closo-1,2,3,4-MC3B7H9 [M ) Mn (7), Re (9)] and 1,1-(CO)2-1-P(C6H5)3-2-Ph-closo-
1,2,3,4-MC3B7H9 [M ) Mn (8), Re (10)]. NMR studies of these reactions at -40 °C showed that substitution
occurs by an associative mechanism involving the initial formation of intermediates having structures similar
to those of the η4-complexes 4 and 5. The observed η6-η4 cage-slippage is analogous to the η5-η3 ring-
slippage that has been proposed to take place in related substitution reactions of cyclopentadienyl-metal
complexes. Reaction of 9 with an additional equivalent of P(CH3)3 gave 8,8-(CO)2-8,8-(P(CH3)3)2-9-Ph-
nido-8,7,9,10-ReC3B7H9 (11), where the cage is η4-coordinated to the metal. Photolysis of 11 resulted in
the loss of CO and the formation of the disubstituted η6-complex 1-CO-1,1-(P(CH3)3)2-2-Ph-closo-1,2,3,4-
ReC3B7H9 (12).
Introduction
We have previously shown that, although the coordination
properties1 of the tricarbadecaboranyl ligand, 6-R-nido-5,6,9-
C3B7H9 [R ) Me,2 Ph1h ], are in many ways similar to those
-
of the cyclopentadienide monoanion (Figure 1), the metalla-
tricarbadecaboranyl complexes have increased oxidative, chemi-
cal, thermal, and hydrolytic stabilities compared to their
metallocene counterparts. For example, the vanadatricarba-
decaboranyl complexes (Me-C3B7H9)2V are air- and moisture-
(1) (a) Plumb, C. A.; Carroll, P. J.; Sneddon, L. G. Organometallics 1992, 11,
1665-1671. (b) Plumb, C. A.; Carroll, P. J.; Sneddon, L. G. Organome-
tallics 1992, 11, 1672-1680. (c) Barnum, B. A.; Carroll, P. J.; Sneddon,
L. G. Organometallics 1996, 15, 645-654. (d) Weinmann, W.; Wolf, A.;
Pritzkow, H.; Siebert, W.; Barnum, B. A.; Carroll, P. J.; Sneddon, L. G.
Organometallics 1995, 14, 1911-1919. (e) Barnum, B. A.; Carroll, P. J.;
Sneddon, L. G. Inorg. Chem. 1997, 36, 1327-1337. (f) Mu¨ller, T.;
Kadlecek, D. E.; Carroll, P. J.; Sneddon, L. G.; Siebert, W. J. Organomet.
Chem. 2000, 614-615, 125-130. (g) Wasczcak, M. D.; Wang, Y.; Garg,
A.; Geiger, W. E.; Kang, S. O.; Carroll, P. J.; Sneddon, L. G. J. Am. Chem.
Soc. 2001, 123, 2783-2790. (h) Ramachandran, B. M.; Carroll, P. J.;
Sneddon, L. G. Inorg. Chem. 2004, 43, 3467-3474. (i) Ramachandran, B.
M.; Carroll, P. J.; Sneddon, L. G. J. Am. Chem. Soc. 2000, 122, 11033-
11034. (j) Ramachandran, B. M.; Trupia, S. M.; Geiger, W. E.; Carroll, P.
J.; Sneddon, L. G. Organometallics 2002, 21, 5078-5090.
Figure 1. Comparison of the structures and bonding modes of the
tricarbadecaboranyl and cyclopentadienyl monoanions.
stable,1g whereas the corresponding vanadocene (η5-C5H5)2V
is not. We have also recently reported1i,j that the tricarba-
decaboranyl ligand is capable of undergoing an η6-η4 cage-
slippage process, with a concomitant decrease in its electron
donation to the metal from six to four electrons, that is analogous
to that of the η5-η3 ring-slippage processes which has been
proposed to occur in the associative substitution reactions of
(2) Kang, S. O.; Furst, G. T.; Sneddon, L. G Inorg. Chem. 1989, 28, 2339-
2347.
9
8626
J. AM. CHEM. SOC. 2006, 128, 8626-8637
10.1021/ja062201u CCC: $33.50 © 2006 American Chemical Society

Mn and Re Tricarbadecaboranyl Tricarbonyl Complexes
A R T I C L E S
Table 1. NMR Data
compd
nucleus
δ (multiplicity, J (Hz), assignment)
2
11Ba,c
1Ha,d
11.4 (d, 162, 1B), 5.5 (d, 142, 1B), 4.6 (d, 147, 1B), 0.3 (d, 149, 1B), -14.4 (d, 150, 1B), -18.2 (d, 159, 1B), -27.2 (d, 162, 1B)
7.03-7.45 (Ph), 6.52 (s, C3H), 2.35 (s, C4H)
3
4
11Ba,c
1Ha,d
4.7 (d, 157, 1B), 1.8 (d, 173, 1B), -0.4 (d, 149, 1B), -4.1 (d, 151, 1B), -18.7 (d, 149, 1B), -20.5 (d, 162, 1B), -31.1 (d, 159, 1B)
6.90-7.23 (Ph), 6.29 (s, C3H), 2.60 (s, C4H)
11Ba,c
1Ha,d
6.8 (d, 137, 1B), 4.8 (d, 129, 1B), -1.4 (d, 133, 1B), -9.7 (d, 139, 1B), -13.7 (d, 175, 1B), -20.5 (d, 140, 1B), -21.2 (d, 165, 1B)
6.93-7.27 (Ph), 3.33 (s, CH), 2.35 (s, CH), 0.89 (s, But)
5
11Ba,c
1Ha,d
6.4 (d, 136, 1B), 2.1 (d, 129, 1B), -3.3 (d, 134, 1B), -11.9 (d, 138, 1B), -15.6 (d, 146, 1B), -23.2 (d, 150, 1B), -24.1 (d, 150, 1B)
6.96-7.23 (Ph), 3.35 (s, CH), 2.74 (s, CH), 0.94 (s, But)
6
11Be,f
1He,g
4.0 (d, 160, 1B), 1.4 (d, 171, 1B), -2.5 (d, 141, 1B), -8.0 (d, 153, 1B), -24.5 (d, 145, 1B), -25.8 (d, 160, 1B), -33.8 (d, 160, 1B)
7.23-7.60 (Ph), 6.23 (s, C3H), 2.68 (s, C4H), 1.25 (s, But)
7
11Ba,c
1Ha,d
4.6 (d, 144, 1B), 1.3 (d, 150, 1B), -0.2 (d, 150, 1B), -3.0 (d, 145, 1B), -20.6 (d, 140, 1B), -24.7 (d, 146, 1B), -32.9 (d, 153, 1B)
7.05-7.72 (Ph), 5.38 (d, 24, C3H), 2.06 (s, C4H), 0.93 (d, 10, Me)
8
11Bb,c
1Hb,d
5.2 (d, 145, 1B), 1.8 (d, 125, 2B), 0.4 (d, 120, 1B), -18.6 (d, 145, 1B), -22.5 (d, 139, 1B), -30.8 (d, 148, 1B)
7.28-7.80 (Ph), 5.59 (d, 23, C3H), 2.34 (s, C4H)
9
11Ba,c
1Ha,d
4.9 (d, 155, 1B), 1.7 (d, 154, 1B), -4.1 (d, 141, 1B), -7.4 (d, 149, 1B), -25.3 (d, 145, 1B), -26.3 (d, 165, 1B), -31.4 (d, 154, 1B)
6.96-7.40 (Ph), 5.06 (d, 15, C3H), 2.06 (s, C4H), 0.95 (d, 10, Me)
10
11
12
11Bb,c
1Hb,d
4.4 (d,h1B), 2.4 (d, 149, 1B). -1.1 (d, 133, 1B), -3.4 (d, 128, 1B), -22.0 (d, 135, 2B), -30.5 (d, 137, 1B)-30.5 (d, 137, 1B)
7.20-7.61 (Ph), 5.57 (d, 17, C3H), 2.69 (s, C4H)
11Be,f
1He,g
-0.4 (d, 140, 1B), -6.9 (d, 139, 1B), -9.0 (d, 141, 1B), -13.7 (d, 130, 1B), -15.4 (d, 170, 1B), -22.1 (d, 145, 1B), -31.4 (d, 139, 1B)
6.95-7.12 (Ph), 2.92 (s, CH), 1.95 (d, 9, Me), 1.92 (d, 9, Me), 1.54 (d, 13, CH)
11Be,f
1He,g
7.5 (d, 144, 1B), -1.5 (d, 148, 1B), -8.8 (d, 132, 1B), -18.8 (d, 142, 1B), -26.0 (d, 146, 1B), -31.6 (d, 130, 1B), -32.6 (d, 170, 1B)
6.97-7.82 (Ph), 3.69 (s, C3H), 1.65 (d, 9, Me), 1.54 (d, 10, Me), 1.50 (d, 22, C4H)
a In C6D6. b In CD2Cl2. c 160.5 MHz. d 500.1 MHz. e In CDCl3. f 128.4 MHz. g 400.1 MHz. h Broad; coupling constant could not be determined.
some metallacyclopentadienyl3 and metalladicarbaborane4 com-
solvents were used as received unless noted otherwise. The yields of
plexes (Figure 1).5 We also suggested1i,j that, since the η6-η4
all metallatricarbaborane products are calculated on the basis of the
starting metal reagents.
process was more facile than the η5-η3 process, metallatricar-
1
Physical Methods. 11B NMR spectra at 128.4 MHz and H NMR
badecaboranyl complexes may exhibit enhanced reactivities
spectra at 400.1 MHz were obtained on a Bruker DMX-400 spectrom-
eter equipped with appropriate decoupling accessories. 11B NMR spectra
compared to their cyclopentadienyl counterparts. In this paper,
we report synthetic, structural, and chemical studies of man-
ganese and rhenium tricarbadecaboranyl tricarbonyl complexes
and demonstrate that these complexes undergo facile carbonyl
substitution reactions with isocyanide and phosphines by an
associative process involving cage-slipped η4-coordinated in-
termediates.
1
at 160.5 MHz, 13C NMR spectra at 125.7 MHz, and H NMR spectra
at 500.1 MHz were obtained on a Bruker AM-500 spectrometer
equipped with the appropriate decoupling accessories. All 11B chemical
shifts are referenced to BF3‚OEt2 (0.0 ppm), with a negative sign
indicating an upfield shift. All proton chemical shifts were measured
relative to internal residual protons from the lock solvents (99.5% C6D6
and 99.9% CD2Cl2) and then referenced to (CH3)4Si (0.0 ppm). NMR
data are summarized in Table 1. Photolyses were performed in Pyrex
vessels using a 450 W medium-pressure Hanovia lamp at 25 °C. High-
and low-resolution mass spectra, employing chemical ionization with
negative ion detection, were obtained on a Micromass AutoSpec high-
resolution mass spectrometer. IR spectra were obtained on a Perkin-
Elmer System 2000 FTIR spectrometer. Elemental analyses were carried
out at Robertson Microlit Laboratories in Madison, NJ. Melting points
were determined using a standard melting point apparatus and are
uncorrected.
Experimental Section
General Synthetic Procedures and Materials. Unless otherwise
noted, all reactions and manipulations were performed in dry glassware
under a nitrogen or argon atmosphere using the high-vacuum or inert-
atmosphere techniques described by Shriver.6
The Li+[6-Ph-nido-5,6,9-C3B7H9-] (1-)1h and [(η6-C10H8)Mn(CO)3+]-
[BF4-]7 were prepared by the reported methods. Re(CO)5Br (Strem),
P(CH3)3, P(C6H5)3, tert-butylisocyanide (Aldrich), spectrochemical grade
diethyl ether, dichloromethane, n-pentane, and hexanes (Fisher) were
used as received. Glyme and tetrahydrofuran (Fisher) were freshly
distilled from sodium benzophenone ketyl prior to use. All other
Synthesis of 1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MnC3B7H9 (2). A
glyme solution of Li+[6-Ph-nido-5,6,9-C3B7H9-] (1-) (3.0 mL of a 0.5
M solution, 1.5 mmol) was added dropwise to a stirring glyme (35
mL) solution of Mn(CO)5Br (412 mg, 1.5 mmol). After being stirred
for 12 h at room temperature, the deep red solution was exposed to air
and filtered through a short plug of silica gel. The silica gel was washed
with diethyl ether to extract any remaining product. The solvent was
vacuum evaporated from the filtrate to give a dark red residue, which
was then redissolved in n-pentane and eluted through a silica gel column
with 100% n-pentane as the eluent. The first red band was collected,
and the solvent was vacuum evaporated to yield a red powder. The
product was further purified by recrystallization from n-pentane at -78
°C to give the red-orange product. For 2: 1,1,1-(CO)3-2-Ph-closo-
1,2,3,4-MnC3B7H9, yield 26% (130 mg, 0.39 mmol); red-orange; mp
66 °C. Anal. Calcd: C, 42.79; H, 4.19. Found: C, 42.37; H, 4.41.
(3) For some examples, see: (a) Basolo, F. New J. Chem. 1994, 18, 19-24
and references therein. (b) Basolo, F. Polyhedron 1990, 9, 1503-1535 and
references therein. (c) O’Connor, J. M.; Casey, C. P. Chem. ReV. 1987,
87, 307-318 and references therein. (d) Schuster-Woldan, H. G.; Basolo,
F. J. Am. Chem. Soc. 1966, 88, 1657-1663. (e) Rerek, M. E.; Basolo, F.
J. Am. Chem. Soc. 1984, 106, 5908-5912. (f) Simanko, W.; Tesch, W.;
Sapunov, V. N.; Mereiter, K.; Schmid, R.; Kirchner, K.; Coddington, J.;
Wherland, S. Organometallics 1998, 17, 5674-5688. (g) Calhorda, M. J.;
Gamelas, C. A.; Roma˜o, C. C.; Veiros, L. F. Eur. J. Inorg. Chem. 2000,
331-340.
(4) Shen, J. K.; Zhang, S.; Basolo, F.; Johnson, S. E.; Hawthorne, M. F. Inorg.
Chim. Acta 1995, 235, 89-97.
(5) For more examples of cage-slipped metalladicarbaboranes, see: (a)
Hawthorne, M. F.; Dunks, G. B. Science 1972, 178, 462-471. (b) Warren,
L. F.; Hawthorne, M. F. J. Am. Chem. Soc. 1968, 90, 4823-4828. (c)
Warren, L. F.; Hawthorne, M. F. J. Am. Chem. Soc. 1970, 92, 1157-1173.
(6) Shriver, D. F.; Drezdzon, M. A. The Manipulation of Air-SensitiVe
Compounds, 2nd ed.; Wiley: New York, 1986.
(7) Sun, S.; Yeung, L. K.; Sweigart, D. A.; Lee, T.-Y.; Lee, S. S.; Chung, Y.
K.; Switzer, S. R.; Pike, R. D. Organometallics 1995, 14, 2613-2615.
LRMS: m/z calcd for 12C11 H1411B716O255Mn- (P-CO) 310, found 310.
1
9
J. AM. CHEM. SOC. VOL. 128, NO. 26, 2006 8627

A R T I C L E S
Butterick et al.
IR (KBr, cm-1): 2963 (s), 2566 (s), 2051 (vs), 2002 (vs), 1964 (vs),
1801 (w), 1582 (w), 1498 (m), 1449 (s), 1261 (s), 1091 (m), 794 (m),
649 (w).
Re-formation of 3 from 5. A CH2Cl2 solution of 5 was vacuum
evaporated, and the resulting yellow powder was dried in vacuo
overnight. The 11B NMR spectrum of a CH2Cl2 solution of the resulting
gold-colored powder was identical to that of 3.
1-(CNBut)-1,1-(CO)2-2-Ph-closo-1,2,3,4-ReC3B7H9 (6). Photolytic
treatment of a CH2Cl2 (10 mL) solution of 5 (50 mg, 0.09 mmol) at
room temperature under a flow of Ar for 1 h resulted in a color change
from yellow to orange. The solvent was vacuum evaporated, and the
resulting orange oil was chromatographed on a TLC plate (3:1
n-pentane/CH2Cl2 eluent) to give 6 (Rf ) 0.66) and other unidentified
minor bands. For 6: 1-(CNBut)-1,1-(CO)2-2-Ph-closo-1,2,3,4-ReC3B7H9,
yield 75.9% (36 mg, 0.07 mmol); orange; mp 101.0 °C. Anal. Calcd:
Alternate Synthesis of 1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MnC3B7H9
(2). A glyme solution of 1- (4.6 mL of a 0.5 M solution, 2.3 mmol)
was added dropwise to a stirring yellow suspension of [(η6-C10H8)-
Mn(CO)3+][BF4-] (797 mg, 2.3 mmol) in CH2Cl2 (25 mL). After being
stirred for 2 h at room temperature, the deep red solution was exposed
to air, and the product was worked up as described above. The red-
orange material, obtained in 42% yield (322 mg, 0.96 mmol), was
1
identified by its 11B NMR and H NMR spectra, mass spectrum, and
melting point.
C, 36.73; H, 4.43; N, 2.68. Found: C, 36.87; H, 4.21; N, 2.70. HRMS
1,1,1-(CO)3-2-Ph-closo-1,2,3,4-ReC3B7H9 (3). Re(CO)5Br (1088 mg,
2.68 mmol) was dissolved in THF (60 mL) and heated at reflux for 16
h. The pale yellow solution was then cooled, a glyme solution of 1-
(3.8 mL of a 0.70 M solution, 2.68 mmol) was added, and the mixture
was refluxed for 4 h. The gold-colored solution was exposed to air
and filtered through a plug of silica gel, and then the filtrate solvent
was vacuum evaporated. The resulting oil was redissolved in CH2Cl2
and eluted through a silica gel column with 10:1 n-pentane:CH2Cl2 as
the eluent. The first gold band was collected, and the solvent was
vacuum evaporated to yield a gold powder. The product was further
purified by recrystallization from n-pentane at -78 °C. For 3: 1,1,1-
(CO)3-2-Ph-closo-1,2,3,4-ReC3B7H9, yield 40.7% (510 mg, 1.09 mmol);
gold; mp 99.5 °C. Anal. Calcd: C, 30.79; H, 3.01. Found: C, 31.01;
12
m/z calcd for
C
1H2311B714N16O2187Re- 525.1937, found 525.1924.
16
IR (KBr, cm-1) 2987 (w), 2566 (s), 2178 (vs), 2001 (vs), 1915 (vs),
1496 (w), 1447 (w), 1372 (w), 1204 (m), 1115 (w), 939 (w), 747 (w),
695 (m).
1,1-(CO)2-1-P(CH3)3-2-Ph-closo-1,2,3,4-MnC3B7H9 (7). A THF
solution of P(CH3)3 (0.60 mL of a 1.0 M solution, 0.60 mmol) was
added dropwise to a stirring n-pentane (10 mL) solution of 2 (100 mg,
0.30 mmol) at room temperature in air, resulting in an immediate color
change from red to red-brown. The solution was filtered through Celite,
and slow evaporation of the filtrate solvent gave dark red-brown colored
crystals. For 7: 1,1-(CO)2-1-P(CH3)3-2-Ph-closo-1,2,3,4-MnC3B7H9,
yield 84.3% (96 mg, 0.25 mmol); dark red-brown; mp 139.5 °C. Anal.
Calcd: C, 43.68; H, 6.02. Found: C, 43.61; H, 5.87. HRMS: m/z calcd
H, 2.83. HRMS: m/z calcd for 12C12 H1411B716O3187Re- 470.1154, found
1
12
-
for
C
1H1411B755Mn16O2 (P-P(CH3)3) 310.1026, found 310.1076.
11
470.1167. IR (KBr, cm-1): 3064 (w), 2612 (m), 2595 (m), 2568 (m),
2063 (vs), 2055 (vs), 1997 (vs), 1947 (vs), 1119 (w), 935 (w), 692
(w), 607 (w).
IR (KBr, cm-1): 2919 (w), 2614 (m), 2583 (m), 2548 (s), 1991 (vs),
1916 (vs), 1294 (w), 1124 (w), 949 (s), 860 (w), 737 (w), 696 (w),
672 (w).
8-(CNBut)-8,8,8-(CO)3-9-Ph-nido-8,7,9,10-MnC3B7H9 (4). CNBut
(0.04 mL, 0.33 mmol) was added dropwise to a stirring n-pentane (2
mL) solution of 2 (100 mg, 0.30 mmol) at room temperature in air,
resulting in an immediate color change from deep red to yellow and
the formation of a yellow precipitate. The solution was cooled at -78
°C to completely precipitate the product, which was then filtered to
yield a yellow powder. For 4: 8-(CNBut)-8,8,8-(CO)3-9-Ph-nido-8,7,9,-
10-MnC3B7H9, yield 94.2% (118 mg, 0.28 mmol); yellow; mp 87.0 °C
(dec). Anal. Calcd: C, 48.62; H, 5.52; N, 3.34. Found: C, 48.71; H,
1,1-(CO)2-1-P(C6H5)3-2-Ph-closo-1,2,3,4-MnC3B7H9 (8). A CH2-
Cl2 (2 mL) solution of P(C6H5)3 (77 mg, 0.30 mmol) and 2 (100 mg,
0.30 mmol) was stirred for 12 h at room temperature in air, resulting
in a color change from dark red to brown. Addition of n-pentane
precipitated a brown powder, which was then filtered and washed with
additional n-pentane. For 8: 1,1-(CO)2-1-P(C6H5)3-2-Ph-closo-1,2,3,4-
MnC3B7H9, yield 73.1% (124 mg, 0.22 mmol); brown; mp 146.0 °C.
Anal. Calcd: C, 60.99; H, 5.12. Found: C, 60.90; H, 4.92. HRMS:
12
-
m/z calcd for
C
1H1411B755Mn16O2 (P-P(C6H5)3) 310.1026, found
11
5.64; N, 3.33. LRMS: m/z calcd for 12C11 H1411B755Mn16O2- (P-CNBut,
1
310.1023. IR (KBr, cm-1): 3058 (w), 2567 (s), 1991 (vs), 1918 (vs),
1435 (m), 1092 (w), 744 (w), 693 (m).
-CO) 310, found 310. IR (KBr, cm-1): 2987 (m), 2594 (m), 2550
(s), 2187 (s), 2055 (vs), 2000 (vs), 1992 (vs), 1194 (m).
1,1-(CO)2-1-P(CH3)3-2-Ph-closo-1,2,3,4-ReC3B7H9 (9). A THF
solution of P(CH3)3 (0.21 mL of a 1.0 M solution, 0.21 mmol) was
added dropwise to a stirring CH2Cl2 (2 mL) solution of 3 (100 mg,
0.21 mmol) at room temperature in air, resulting in an immediate color
change from gold to bright yellow, which then faded to orange after 5
min. Addition of n-pentane precipitated an orange powder that was
then filtered and washed with additional n-pentane. For 9: 1,1-(CO)2-
1-P(CH3)3-2-Ph-closo-ReC3B7H9, yield 93.9% (104 mg, 0.20 mmol);
Re-formation of 2 from 4. A CH2Cl2 solution of 4 was vacuum
evaporated, and the resulting yellow powder was dried in vacuo
overnight. The 11B NMR spectrum of a CH2Cl2 solution of the resulting
red powder was identical to that of 2.
Attempted Synthesis of 1-(CNBut)-1,1-(CO)2-2-Ph-closo-1,2,3,4-
MnC3B7H9. Photolytic treatment of a CH2Cl2 (10 mL) solution of 4
(84 mg, 0.20 mmol) at room temperature under a flow of Ar for 1 h
resulted in a color change from yellow to brown. The 11B NMR
spectrum consisted of seven equal intensity peaks (2.4, 0.4, -0.5, -5.0,
-23.8, -27.2, -33.7 ppm) and indicated the formation of an
η6-coordinated complex; however, because of fast decomposition, the
product could not be isolated.
orange; mp 188.0 °C. Anal. Calcd: C, 32.58; H, 4.49. Found: C, 31.95;
12
H, 4.20. HRMS: m/z calcd for
C
1H2311B716O231P187Re- 518.1644,
14
found 518.1622. IR (KBr, cm-1): 2570 (s), 1994 (vs), 1876 (vs), 1293
(w), 942 (m).
1,1-(CO)2-1-P(C6H5)3-2-Ph-closo-1,2,3,4-ReC3B7H9 (10). A CH2-
Cl2 (2 mL) solution of P(C6H5)3 (56 mg, 0.21 mmol) and 3 (100 mg,
0.21 mmol) was stirred for 12 h at room temperature in air, resulting
in a color change from gold to orange. Addition of n-pentane
precipitated an orange powder, which was then filtered and washed
with additional n-pentane. For 10: 1,1-(CO)2-1-P(C6H5)3-2-Ph-closo-
1,2,3,4-ReC3B7H9, yield 93.1% (140 mg, 0.20 mmol); orange; mp 253.0
8-(CNBut)-8,8,8-(CO)3-9-Ph-nido-8,7,9,10-ReC3B7H9 (5). CNBut
(0.03 mL, 0.23 mmol) was added dropwise to a stirring n-pentane (2
mL) solution of 3 (100 mg, 0.21 mmol) at room temperature in air,
resulting in an immediate color change from yellow-gold to yellow
and the formation of a yellow precipitate. The solution was cooled at
-78 °C to completely precipitate the product, which was then filtered
to yield a yellow powder. For 5: 8-(CNBut)-8,8,8-(CO)3-9-Ph-nido-
8,7,9,10-ReC3B7H9, yield 88.3% (104 mg, 0.19 mmol); yellow; mp
137.0 °C (dec). Anal. Calcd: C, 37.04; H, 4.21; N, 2.54. Found: C,
°C. Anal. Calcd: C, 49.59; H, 4.16. Found: C, 49.23; H, 3.91.
12
LRMS: m/z calcd for
C
1H1411B716O231P187Re- (P-P(C6H5)3) 442,
11
found 442. IR (KBr, cm-1): 3059 (w), 2565 (m), 1996 (vs), 1903 (vs),
1435 (m), 1094 (w), 744 (w), 693 (m).
37.25; H, 3.99; N, 2.59. LRMS: m/z calcd for 12C12 H1411B716O3187Re-
1
(P-CNBut) 470, found 470. IR (KBr, cm-1): 2989 (w), 2583 (m),
8,8-(CO)2-8,8-(P(CH3)3)2-9-Ph-nido-8,7,9,10-ReC3B7H9 (11). A
THF solution of P(CH3)3 (0.21 mL of a 1.0 M solution, 0.21 mmol)
2552 (s), 2202 (s), 2059 (vs), 2000 (vs), 1979 (vs), 1192 (m).
9
8628 J. AM. CHEM. SOC. VOL. 128, NO. 26, 2006

Mn and Re Tricarbadecaboranyl Tricarbonyl Complexes
A R T I C L E S
was added dropwise to a stirring CH2Cl2 (2 mL) solution of 9 (100
mg, 0.21 mmol) at room temperature in air, resulting in an immediate
color change from orange to dull yellow. Addition of n-pentane
precipitated a yellow powder that was then filtered and washed with
additional n-pentane. For 11: 8,8-(CO)2-8,8-(P(CH3)3)2-9-Ph-nido-
8,7,9,10-ReC3B7H9, yield 87.4% (100 mg, 0.17 mmol); yellow; mp
Results and Discussion
Syntheses and Structural Characterizations of 1,1,1-
(CO)3-2-Ph-closo-1,2,3,4-MC3B7H9 [M ) Mn, Re]. Analogous
to the reaction of Tl+[C5H5-] with Mn(CO)5Cl,16 the room-
temperature reaction of 1- with Mn(CO)5Br resulted in the
displacement of two carbonyl groups and the bromide to give
the η6-tricarbadecaboranyl manganese tricarbonyl product, 2 (eq
1), in a 26% yield after 12 h.
140.0 °C (dec). Anal. Calcd: C, 34.48; H, 5.45. Found: C, 34.39; H,
12
5.18. HRMS: m/z calcd for
C
1H2311B716O231P187Re- (P-P(CH3)3)
14
518.1644, found 518.1630. IR (KBr, cm-1): 2916 (w), 2548 (s), 1981
(vs), 1903 (vs), 1426 (w), 1292 (w), 952 (s).
Mn(CO)5Br + Li+[6-Ph-nido-5,6,9-C3B7H9 ] (1-) f
-
1-CO-1,1-(P(CH3)3)2-2-Ph-closo-1,2,3,4-ReC3B7H9 (12). Photolytic
treatment of a CH2Cl2 (2 mL) solution of 11 (100 mg, 0.17 mmol) at
room temperature under a flow of Ar for 5 h resulted in a color change
from yellow to orange. The solvent was then vacuum evaporated,
resulting in a dark orange oil. The oil was then chromatographed on a
TLC plate (toluene eluent) to give 12 (Rf ) 0.55), 11 (Rf ) 0.65), and
9 (Rf ) 0.76). Compounds 11 and 9 were identified by their 11B NMR
shifts and melting points. For 12: 1-CO-1,1-(P(CH3)3)2-2-Ph-closo-
1,2,3,4-ReC3B7H9, yield 15.1% (14.5 mg, 0.03 mmol); dark orange;
mp 192.0 °C. Anal. Calcd: C, 34.06; H, 5.72. Found: C, 33.97; H,
1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MnC3B7H9 (2) +
2CO + LiBr (1)
Alternatively, the room-temperature reaction of the naphtha-
lene manganese tricarbonyl transfer agent,17 [(η6-C10H8)Mn-
(CO)3+][BF4-], with 1- gave 2 in 42% yield in only 2 h (eq
2).
+
-
[(η6-C10H8)Mn(CO)3 ][BF4 ] +
Li+[6-Ph-nido-5,6,9-C3B7H9 ] (1-) f
-
5.47. HRMS: m/z calcd for 12C16 H3211B716O31P2187Re- 566.2137, found
1
566.2121. IR (KBr, cm-1) 2974 (w), 2911 (w), 2543 (s), 1868 (vs),
1623 (w, br), 1598 (w), 1493 (w), 1429 (m), 1420 (m), 1308 (w), 1287
(s), 1115 (w), 958 (s), 945 (s), 865 (m), 729 (m), 694 (w), 675 (m).
1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MnC3B7H9 (2) +
C10H8 + LiBF4 (2)
Crystallographic Data. Single crystals of compounds 2-12 were
grown via slow solvent evaporation from dichloromethane or n-pentane
solution in air.
The synthesis of 3, in 41% yield, was achieved by the reaction
of Re(CO)3(THF)2Br,18 obtained by THF reflux of Re(CO)5Br
for 16 h, with 1- (eq 3).
Collection and Reduction of the Data. Crystallographic data and
structure refinement information are summarized in Table 2. X-ray
intensity data for 2 (Penn3186), 3 (Penn3232), 4 (Penn3233), 5
(Penn3236), 6 (Penn3259), 7 (Penn3214), 8 (Penn3235), 9 (Penn3242),
10 (Penn3239), 11 (Penn3258), and 12 (Penn3262) were collected on
either Rigaku R-AXIS IIC (for 2) or Mercury CCD area detectors
employing graphite-monochromated Mo KR radiation (λ ) 0.71069
Å). Indexing was performed from a series of twelve 0.5° rotation images
with exposures of 30 s and a 36 mm crystal-to-detector distance, except
for 2, where a series of 1° oscillation images with exposures of 100
s/frame and an 82 mm crystal-to-detector distance were employed.
Oscillation images were processed using bioteX8 (for 2) and Crystal-
Clear,9 producing a list of unaveraged F 2 and σ(F 2) values which were
then passed to the teXsan10 (for 2) or CrystalStructure11 program
packages for further processing and structure solution on a Silicon
Graphics Indigo R4000 computer (for 2) or a Dell Pentium III computer.
The intensity data were corrected for Lorentz and polarization effects
and for absorption except for 2, which was corrected for Lorentz and
polarization effects, but not for absorption.
Re(CO)3(THF)2Br+Li+[6-Ph-nido-5,6,9-C3B7H9 ](1-) f
-
1,1,1-(CO)3-2-Ph-closo-1,2,3,4-ReC3B7H9 (3) +
2THF + LiBr (3)
2 and 3 were easily separated in pure form from other
unidentified minor products and Mn2(CO)10 and Re2(CO)10,
respectively, by column chromatography. 2 and 3 are soluble
in a wide variety of both polar and nonpolar organic solvents,
including diethyl ether, methylene chloride, and toluene, but
unlike 2, 3 is only slightly soluble in n-pentane. Both 2 and 3
are air- and moisture-stable.
The 11B NMR spectra (Table 1) of 2 and 3, like those of the
previously known 1,1,1-(CO)3-2-Me-closo-1,2,3,4-MnC3B7H9,1a
indicate C1 cage symmetry, showing seven doublets at chemical
shifts consistent with those observed for other closo-1,2,3,4-
1
MC3B7H9 cluster systems.1 Their H NMR spectra each show
two C-H resonances, one occurring at a higher-field shift (2.4-
2.6 ppm), characteristic of a proton attached to the C4 cage
atom, and the other at a lower-field shift (6.3-6.5 ppm),
characteristic of a proton attached to a low-coordinate carbon
adjacent to the metal (C3H).1
In agreement with the spectroscopic data and the predicted
closo-electron count of their MC3B7H9 fragments (24 skeletal
electrons), crystallographic determinations of 2 and 3 confirm
that the metallatricarbadecaboranyl cages adopt octadecahedral
geometries (Figures 2 and 3) with the metal η6-coordinated to,
and approximately centered over, the puckered six-membered
face of the tricarbadecaboranyl cage. The closest metal-cage
interactions are with the two carbons that are puckered out of
Solution and Refinement of the Structures. The structures were
solved by direct methods (SIR9212 (for 2) or SIR9713). Refinement was
by full-matrix least-squares based on F 2 using SHELXL-9314 (for 2)
or SHELXL-97.15 All reflections were used during refinement (values
of F 2 that were experimentally negative were replaced with F 2 ) 0).
(8) bioteX: A suite of Programs for the Collection, Reduction and Interpretation
of Imaging Plate Data; Molecular Structure Corporation, 1995.
(9) CrystalClear; Rigaku Corporation, 1999.
(10) teXsan: Crystal Structure Analysis Package; Molecular Structure Corpora-
tion, 1985, 1992.
(11) CrystalStructure: Crystal Structure Analysis Package; Rigaku Corp. Rigaku/
MSC, 2002.
(12) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, M.; Giacovazzo, C.;
Guagliardi, A.; Polidoro, G. J. Appl. Crystallogr. 1994, 27, 435.
(13) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, M.; Giacovazzo, C.;
Guagliardi, A.; Moliterni, A.; Polidori, G. J.; Spagna, R. J. Appl.
Crystallogr. 1999, 32, 115-119.
(14) Sheldrick, G. M. SHELXL-93: Program for the Refinement of Crystal
Structures; University of Go¨ttingen: Germany, 1993.
(15) Sheldrick, G. M. SHELXL-97: Program for the Refinement of Crystal
Structures; University of Go¨ttingen: Germany, 1997.
(16) Nesmeyanov, A. N.; Anisimov, K. N.; Kolobova, N. E. IzV. Akad. Nauk
SSSR, Ser. Khim. 1964, 12, 2220.
(17) Oh, M.; Reingold, J. A.; Carpenter, G. B.; Sweigart, D. A. Coord. Chem.
ReV. 2004, 248, 561-596.
(18) Ellis, D. D.; Jelliss, P. A.; Stone, F. G. A. Organometallics 1999, 18, 4982-
4994.
9
J. AM. CHEM. SOC. VOL. 128, NO. 26, 2006 8629

A R T I C L E S
Butterick et al.
2.
Table
9
8630 J. AM. CHEM. SOC. VOL. 128, NO. 26, 2006

Mn and Re Tricarbadecaboranyl Tricarbonyl Complexes
A R T I C L E S
Mn(CO)319 (2.133(3)-2.142(3) Å), (η5-C5Me5)Mn(CO)320 (2.112-
(7)-2.137(8) Å), (η5-C5H5)Re(CO)321 (2.280(7)-2.292(9) Å),
and (η5-C5Me5)Re(CO)3 (2.286(8)-2.313(7) Å). Although
22
there are no statistical differences between the C-O bond
distances observed in 2 and 3 and those of their corresponding
cyclopentadienyl counterparts, the average M-C(carbonyl)
distances in 2 (1.818(3) Å) and 3 (1.943(4) Å) are longer than
the M-C(carbonyl) distances in (η5-C5H5)Mn(CO)3 (1.793(3)
Å) and (η5-C5Me5)Mn(CO)3 (1.725(11) Å) and in (η5-C5H5)-
Re(CO)3 (1.894(7) Å) and (η5-C5Me5)Re(CO)3 (1.891(10) Å),
respectively.
Consistent with the differences observed in their M-C(car-
bonyl) distances, the CO stretching absorptions in the IR
spectrum of 1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MnC3B7H9 are at
higher energies (2051, 2002, and 1964 cm-1, KBr) than those
of (η5-C5H5)Mn(CO)3 (2027 and 1944 cm-1, KBr) and (η5-C5-
Me5)Mn(CO)3 (2004 and 1910 cm-1, KBr).23 Likewise, the CO
stretching absorptions in 1,1,1-(CO)3-2-Ph-closo-1,2,3,4-ReC3B7H9
are at higher energies (2055, 1997, and 1947 cm-1, KBr) than
those of (η5-C5H5)Re(CO)3 (2025 and 1926 cm-1, KBr) and
(η5-C5Me5)Re(CO)3 (2007 and 1909 cm-1, KBr).23 Thus, both
the IR and M-C(carbonyl) bond distance data indicate that, in
2 and 3, there is less metal-to-CO back-bonding than in their
cyclopentadienyl analogues. As previously noted, this is con-
sistent with tricarbadecaboranyl ligands being more electron-
withdrawing than their cyclopentadienyl counterparts.1a The CO
stretching absorptions of the previously synthesized 1,1,1-(CO)3-
Figure 2. ORTEP representation of the structure of 1,1,1-(CO)3-2-Ph-closo-
1,2,3,4-MnC3B7H9 (2). Selected distances (Å) and angles (deg): Mn1-
C2, 2.096(2); Mn1-C3, 2.050(2); Mn1-C4, 2.415(2); Mn1-B5, 2.345(3);
Mn1-B6, 2.342(3); Mn1-B7, 2.408(3); C2-C12, 1.490(3); C2-C4,
1.509(3); C4-B7, 1.754(4); B7-C3, 1.577(4); C3-B6, 1.561(4); B6-B5,
1.886(4); B5-C2, 1.582(3); Mn1-C18, 1.836(3); C18-O19, 1.145(3);
Mn1-C20, 1.792(2); C20-O21, 1.149(3); Mn1-C22, 1.826(3); C22-O23,
1.141(3); C2-Mn1-C3, 103.7(1); Mn1-C2-C12, 123.0(2); C2-Mn1-
C18, 83.1(1); C2-Mn1-C20, 108.5(1); C2-Mn1-C22, 155.9(1); C3-
Mn1-C18, 153.5(1); C3-Mn1-C20, 111.1(1); C3-Mn1-C22, 80.6(1);
Mn1-C18-O19, 177.1(2); Mn1-C20-O21, 177.3(2); Mn1-C22-O23,
179.4(2).
2-Me-closo-1,2,3,4-MnC3B7H9 (2040, 2008, and 1960 cm-1
,
KBr) are also at lower energies than those of 2, indicating, as
noted before,1h that the phenyl-functionalized tricarbadecabor-
anyl ligand is more electron-withdrawing than the methyl
derivative.
Monosubstitution Reactions. The carbonyl substitution
reactions of cyclopentadienyl manganese and rhenium tricar-
bonyl have been extensively studied.24 These reactions could,
in principle, go by either a dissociative mechanism, involving
initial dissociation of one carbonyl followed by ligand attack
(eq 4), or an associative mechanism, involving coordination of
the incoming ligand before loss of the carbon monoxide (eq
5).
Figure 3. ORTEP representation of the structure of 1,1,1-(CO)3-2-Ph-closo-
1,2,3,4-ReC3B7H9 (3). Selected distances (Å) and angles (deg): Re1-C2,
2.202(4); Re1-C3, 2.169(3); Re1-C4, 2.546(4); Re1-B5, 2.432(5); Re1-
B6, 2.450(5); Re1-B7, 2.543(4); C2-C12, 1.500(5); C2-C4, 1.517(5);
C4-B7, 1.772(6); B7-C3, 1.587(6); C3-B6, 1.577(7); B6-B5, 1.915(6);
B5-C2, 1.602(6); Re1-C18, 1.971(4); C18-O19, 1.142(5); Re1-C20,
1.906(4); C20-O21, 1.140(5); Re1-C22, 1.953(4); C22-O23, 1.134(5);
C2-Re1-C3, 98.6(2); Re1-C2-C12, 121.6(3); C2-Re1-C18, 83.7(2);
C2-Re1-C20, 110.9(2); C2-Re1-C22, 155.9(1); C3-Re1-C18, 154.4(2);
C3-Re1-C20, 113.3(2); C3-Re1-C22, 83.6(2); Re1-C18-O19, 178.8(4);
Re1-C20-O21, 174.9(3); Re1-C22-O23, 179.5(4).
(η5-C5H5)M(CO)3 -CO8
(η5-C5H5)M(CO)2
9
L8 (η5-C5H5)M(CO)2L (4)
(η5-C5H5)M(CO)3
9
L8 (η3-C5H5)M(CO)3L -CO8
(η5-C5H5)M(CO)2L (5)
The latter mechanism has been proposed to involve an η5-
η3 ring-slippage process that both opens up a metal coordination
the ring, for 2 (Mn1-C2, 2.096(2) and Mn1-C3, 2.050(2) Å)
and for 3 (Re1-C2, 2.202(4) and Re1-C3, 2.169(3) Å). Longer
and approximately equivalent distances are observed between
the metal and the remaining four atoms of the tricarbadecabor-
anyl bonding face, for 2 (Mn1-C4, 2.415(2); Mn1-B5, 2.345-
(3); Mn1-B6, 2.342(3); Mn1-B7, 2.408(3) Å) and for 3 (Re1-
C4, 2.546(4); Re1-B5, 2.432(5); Re1-B6, 2.450(5); Re1-B7,
2.543(4) Å). The phenyl group in both compounds is attached
to the C2 cage carbon adjacent to the metal. The M-C2 and
M-C3 distances are significantly shorter than the M-C
distances to the ring carbons found in the analogous (η5-C5H5)-
(19) Cowie, J.; Hamilton, E. J. M.; Laurie, J. C. V.; Welch, A. J. J. Organomet.
Chem. 1990, 394, 1-13.
(20) Fortier, S.; Baird, M. C.; Preston, K. F.; Morton, J. R.; Ziegler, T.; Jaeger,
T. J.; Watkins, W. C.; MacNeil, J. H.; Watson, K. A.; Hensel, K.; Le Page,
Y.; Charland, J.-P.; Williams, A. J. J. Am. Chem. Soc. 1991, 113, 542-
551.
(21) Fitzpatrick, P. J.; Le Page, Y.; Butler, I. S. Acta Crystallogr. 1981, B37,
1052-1058.
(22) Huang, Y.; Butler, I. S.; Gilson, D. F. R. Inorg. Chem. 1992, 31, 4762-
4765.
(23) Bencze, EÄ .; Mink, J.; Ne´meth, C.; Herrmann, W. A.; Lokshin, B. V.; Ku¨hn,
F. E. J. Organomet. Chem. 2002, 642, 246-258.
(24) (a) Caulton, K. G. Coord. Chem. ReV. 1981, 38, 1-43. (b) Manuel, T. A.
AdV. Organomet. Chem. 1965, 3, 181-261.
9
J. AM. CHEM. SOC. VOL. 128, NO. 26, 2006 8631

A R T I C L E S
Butterick et al.
site for the incoming ligand and enables the metal to maintain
its 18-electron configuration following ligand association.
Because (η5-C5H5)Mn(CO)3 is thermally inert,25 substitution
has usually been achieved through the photolysis of the complex
in a donor solvent (eq 6), followed by addition of the substituting
ligand (eq 7).
process, analogous to the η5-η3 ring-slippage of the cyclopen-
tadienyl complexes discussed above, to yield η4-coordinated
complexes (eqs 8 and 9).1i,j
1-(η5-C5Me5)-2-Me-closo-1,2,3,4-RuC3B7H9 + CNBut f
8-(η5-C5Me5)-8-(CNBut)-9-Me-nido-8,7,9,10-RuC3B7H9
(8)
(η5-C5H5)Mn(CO)3 + THF
(η5-C5H5)Mn(CO)2(THF) + CO (6)
9
hV8
1-(η5-C5Me5)-2-Ph-closo-1,2,3,4-FeC3B7H9 + CNBut f
8-(η5-C5Me5)-8-(CNBut)-9-Ph-nido-8,7,9,10-FeC3B7H9 (9)
(η5-C5H5)Mn(CO)2(THF)
L8 (η5-C5H5)Mn(CO)2L (7)
9
It was likewise found that, when tert-butyl isocyanide was
added to solutions of 2 and 3, the yellow η4 cage-slipped
tricarbonyl isocyanide complexes, 4 and 5, were produced (eq
10).
The rate of THF substitution from (η5-C5H5)Mn(CO)2(THF)
(eq 7) was shown to be dependent upon the THF concentration
but independent of the nature of the incoming ligand, L,26 thus,
indicating a dissociative process. Likewise, the thermal substitu-
tion of (η5-C5H4C(O)CH3)Mn(CO)2SC4H8, (η1:η5-C5H4C(O)CH2-
SCH3)Mn(CO)2, and (η1:η5-C5H4C(O)CH2CH2SCH3)Mn(CO)2,
derivatives of (η5-C5H5)Mn(CO)3, by a number of phosphines
and phosphites was also proposed to proceed through a
dissociative pathway, because the observed rate constants were
independent of both the solvent and the concentration of the
incoming ligand, and the reactions were determined to have a
positive entropy of activation.27
In contrast to the dissociative reactions described above,
Basolo found that the monosubstitution reactions of (η5-C9H7)-
Mn(CO)3 and (η5-C13H9)Mn(CO)3 with phosphines were second
order and had large, negative entropies of activation, indicating
that they were reacting via an associative mechanism involving
η3 ring-slipped intermediates.28 Supporting such a process, Son
structurally confirmed29 that the (η3-C10H9)Mn(CO)3P(OMe)3
complex was produced by the reaction of (η5-C10H9)Mn(CO)3
with P(OMe)3 and then showed that, upon heating29 or pho-
tolysis,30 this complex lost CO to produce (η5-C10H9)Mn(CO)2P-
(OMe)3.
Substitution reactions of (η5-C5H5)Re(CO)3 have been achieved
through photolytic means similar to those discussed above for
(η5-C5H5)Mn(CO)3,24 but (η5-C5H5)Re(CO)3, unlike (η5-C5H5)-
Mn(CO)3, also readily undergoes thermally activated substitu-
tion. For example, Casey and co-workers demonstrated that the
reaction of (η5-C5H5)Re(CO)3 with P(CH3)3 produced both fac-
(η1-C5H5)Re(CO)3(P(CH3)3)2 and (η5-C5H5)Re(CO)2P(CH3)3.31
It was reported that the rate of these reactions depended on the
concentration of both (η5-C5H5)Re(CO)3 and P(CH3)3, and
therefore the formation of both (η1-C5H5)Re(CO)3(P(CH3)3)2 and
(η5-C5H5)Re(CO)2P(CH3)3 must proceed through an associative
mechanism via a ring-slipped intermediate, (η3-C5H5)Re(CO)3P-
(CH3)3.
1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MC3B7H9 + CNBut f
[M ) Mn (2), Re (3)]
8-(CNBut)-8,8,8-(CO)3-9-Ph-nido-8,7,9,10-MC3B7H9
[M ) Mn (4), Re (5)]
(10)
4 and 5 precipitated when the reaction was carried out in
n-pentane. Both compounds are air- and moisture-stable. The
11B NMR spectra (Table 1) of 4 and 5 are similar to those of
1-(η5-C5Me5)-2-Me-closo-1,2,3,4-RuC3B7H9 and 1-(η5-C5Me5)-
2-Ph-closo-1,2,3,4-FeC3B7H9.1i,j The 1H NMR spectra of 4 and
5 show, as in compounds 2 and 3, a higher-field C-H resonance
(2.4-2.7 ppm) and a lower-field resonance (3.3-3.4 ppm) for
each hydrogen attached to a cage carbon.
The change in cage hapticity observed in these reactions, like
the η5-η3 ring-slippage process, reduces the electron donation
of the tricarbadecaboranyl anion from six to four electrons, thus
allowing the preservation of the 18-electron count of the metal
upon the association of an incoming two-electron ligand. From
a skeletal electron counting viewpoint, the addition of the two-
electron isocyanide ligand to 2 and 3 increases the skeletal
electron count of the metallatricarbadecaboranyl fragment to
26 skeletal electrons. Therefore, 4 and 5 should adopt open-
cage 11-vertex nido geometries, based on an icosahedron
missing one vertex. Crystallographic determinations of 4 and 5
confirm the predicted nido (i.e., slipped cage) geometries. In
principle, the metal could slip to either the C7-B3-B4-C9
face or the C9-C10-B11-C7 face of the tricarbadecaboranyl
cage. However, in agreement with the known preference of
carbon atoms to adopt low-coordinate positions on the open
face of clusters,32 the slip occurs such that the metals become
η4-coordinated to, and approximately centered over, the C7-
B3-B4-C9 faces of the tricarbadecaboranyl cages (Figures 4
and 5), thus producing five-membered (M-C7-B11-C10-
C9) open faces containing all three cage carbons. The Mn8-
C7 (2.244(2) Å), Mn8-C9 (2.267(2) Å), Re8-C7 (2.308(4)
Å), and Re8-C9 (2.330(4) Å) distances are longer than the
analogous distances in 2 and 3, while the Mn8-B4 (2.311(2)
Å), Mn8-B3 (2.340(3) Å), Re8-B4 (2.395(4) Å), and Re8-
B3 (2.420(5) Å) distances are shorter. Because of these
differences and the fact that the C10 and B11 cage atoms are
not within bonding distances to the metals (Mn8-C10, 3.135-
(2) Å; Mn8-B11, 3.146(3) Å; Re8-C10, 3.210(5) Å; Re8-
In the reactions of 1-(η5-C5Me5)-2-Me-closo-1,2,3,4-RuC3B7H9
and 1-(η5-C5Me5)-2-Ph-closo-1,2,3,4-FeC3B7H9 with tert-butyl
isocyanide, the addition of two electrons to the metal caused
the 6-Ph-nido-5,6,9-C3B7H9- ligand to undergo a cage-slippage
(25) Angelici, R. J.; Loewen, W. Inorg. Chem. 1967, 6, 682-686.
(26) Coleman, J. E.; Dulaney, K. E.; Bengali, A. A. J. Organomet. Chem. 1999,
572, 65-71.
(27) Pang, Z.; Johnston, R. F. Polyhedron 1999, 18, 3469-3477.
(28) Ji, L.-N.; Rerek, M. E.; Basolo, F. Organometallics 1984, 3, 740-745.
(29) Son, S. U.; Paik, S.-J.; Lee, I. S.; Lee, Y.-A.; Chung, Y. K.; Seok, W. K.;
Lee, H. N. Organometallics 1999, 18, 4114-4118.
(30) Georg, A.; Kreiter, C. G. Eur. J. Inorg. Chem. 1999, 651-654.
(31) Casey, C. P.; O’Connor, J. M.; Jones, W. D.; Haller, K. J. Organometallics
1983, 2, 535-538.
(32) Williams, R. E. AdV. Inorg. Chem. Radiochem. 1976, 18, 67-142.
9
8632 J. AM. CHEM. SOC. VOL. 128, NO. 26, 2006

Mn and Re Tricarbadecaboranyl Tricarbonyl Complexes
A R T I C L E S
Figure 4. ORTEP representation of the structure of 8-(CNBut)-8,8,8-(CO)3-
9-Ph-nido-8,7,9,10-MnC3B7H9 (4). Selected distances (Å) and angles
(deg): Mn8-C9, 2.267(2); Mn8-C7, 2.244(2); Mn8-C10, 3.135(2); Mn8-
B4, 2.311(2); Mn8-B3, 2.340(3); Mn8-B11, 3.146(3); C9-C12, 1.501(3);
C9-C10; 1.518(3); C10-B11, 1.656(3); B11-C7, 1.586(3); C7-B3,
1.585(3); B3-B4, 1.924(3); B4-C9, 1.593(3); Mn8-C18, 1.838(2); C18-
O19, 1.142(3); Mn8-C20, 1.840(2); C20-O21, 1.138(3); Mn8-C22,
1.832(2); C22-O23, 1.137(3); Mn8-C24, 1.974(2); C24-N25, 1.154(3);
C9-Mn8-C7, 80.9(1); Mn8-C9-C12, 112.6(1); C9-Mn8-C18, 91.8-
(1); C9-Mn8-C20, 110.0(1); C9-Mn8-C22, 164.1(1); C9-Mn8-C24,
81.4(1); C7-Mn8-C18, 164.0(1); C7-Mn8-C20, 110.4(1); C7-Mn8-
C22, 89.6(1); C7-Mn8-C24, 78.6(1); Mn8-C18-O19, 178.9(2); Mn8-
C20-O21, 175.0(2); Mn8-C22-O23, 179.2(2); Mn8-C24-N25, 175.3(2).
Figure 6. ORTEP representation of the structure of 1-(CNBut)-1,1-(CO)2-
2-Ph-closo-1,2,3,4-ReC3B7H9 (6). Selected distances (Å) and angles (deg):
Re1-C2, 2.200(3); Re1-C3, 2.114(3); Re1-C4, 2.559(3); Re1-B5, 2.423-
(4); Re1-B6, 2.413(4); Re1-B7, 2.505(4); C2-C12, 1.506(4); C2-C4,
1.521(4); C4-B7, 1.745(5); B7-C3, 1.611(5); C3-B6, 1.605(5); B6-B5,
1.874(5); B5-C2, 1.603(5); Re1-C18, 1.945(3); C18-O19, 1.133(5); Re1-
C20, 1.907(4); C20-O21, 1.151(5); Re1-C22, 2.039(3); C22-N23, 1.148-
(4); C2-Re1-C3, 99.6(1); Re1-C2-C12, 122.7(2); C2-Re1-C18,
165.7(1); C2-Re1-C20, 106.6(1); C2-Re1-C22, 83.7(1); C3-Re1-C18,
83.2(1); C3-Re1-C20, 122.6(1); C3-Re1-C22, 139.9(1); Re1-C18-
O19, 178.6(3); Re1-C20-O21, 176.2(3); Re1-C22-N23, 174.7(3).
to 4 and 5, the isocyanide was lost and 2 and 3 were
quantitatively re-formed (eq 11).
8-(CNBut)-8,8,8-(CO)3-9-Ph-nido-8,7,9,10-MC3B7H9 vacuum8
[M ) Mn (4), Re (5)]
1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MC3B7H9 + CNBut
[M ) Mn (2), Re (3)]
(11)
On the other hand, photolysis of a CH2Cl2 solution of 5 for
1 h resulted in loss of CO and formation of the monosubstituted
product, 6 (eq 12).
8-(CNBut)-8,8,8-(CO)3-9-Ph-nido-8,7,9,10-ReC3B7H9 (5)
9
hV8 1-(CNBut)-1,1-(CO)2-2-Ph-closo-1,2,3,4-ReC3B7H9 (6)
Figure 5. ORTEP representation of the structure of 8-(CNBut)-8,8,8-(CO)3-
9-Ph-nido-8,7,9,10-ReC3B7H9 (5). Selected distances (Å) and angles
(deg): Re8-C9, 2.330(4); Re8-C7, 2.308(4); Re8-C10, 3.210(5); Re8-
B4, 2.395(4); Re8-B3, 2.420(5); Re8-B11, 3.229(5); C9-C12, 1.509(5);
C9-C10, 1.519(5); C10-B11, 1.651(6); B11-C7, 1.593(6); C7-B3,
1.583(6); B3-B4, 1.946(6); B4-C9, 1.614(5); Re8-C18, 1.947(4); C18-
O19, 1.147(5); Re8-C20, 1.967(4); C20-O21, 1.141(5); Re8-C22, 1.963-
(4); C22-O23, 1.128(5); Re8-C24, 2.088(4); C24-N25, 1.160(5); C9-
Re8-C7, 78.3(1); Re8-C9-C12, 112.2(2); C9-Re8-C18, 92.4(2); C9-
Re8-C20, 109.6(2); C9-Re8-C22, 163.8(2); C9-Re8-C24, 81.0(1); C7-
Re8-C18, 163.6(2); C7-Re8-C20, 109.4(2); C7-Re8-C22, 91.9(2); C7-
Re8-C24, 78.4(2); Re8-C18-O19, 178.0(4); Re8-C20-O21, 176.4(4);
Re8-C22-O23, 177.9(4); Re8-C24-N25, 175.9(3).
+ CO (12)
The 11B NMR spectrum (Table 1) of 6 is similar to that of 3.
The H spectrum of 6, like those of 2 and 3, shows two C-H
1
resonances: a higher-field (2.68 ppm) peak, consistent with a
proton attached to the C4 carbon, and a lower-field (6.23 ppm)
peak, consistent with a proton attached to the C3 carbon.
6 is isoelectronic with 3 and should adopt a similar 11-vertex
closo geometry. In agreement with the spectroscopic data and
its predicted closo geometry, a crystallographic determination
of 6 confirmed that the metallatricarbadecaboranyl cage adopts
an octadecahedral geometry (Figure 6) with the metal again η6-
coordinated to, and approximately centered over, the puckered
six-membered face of the tricarbadecaboranyl cage. The metal-
to-cage distances in 6 are similar to those found in 3, with the
exception of shorter Re1-C3 (2.169(3) Å, 3; 2.114(3)Å, 6),
Re1-B6 (2.450(5) Å, 3; 2.413(4) Å, 6), and Re1-B7 (2.543-
B11, 3.229(5) Å), the dihedral angles between the C7-M-C9
and C9-C10-B11-C7 planes in 4 (29.4(1)°) and 5 (29.3(3)°)
are significantly smaller than the equivalent dihedral angle
between the C2-M-C3 and C2-C4-B7-C3 planes in 2
(62.4(1)°) and 3 (61.2(1)°).
As previously observed for the ruthenium and iron systems
discussed above,1i,j it was found that, when vacuum was applied
9
J. AM. CHEM. SOC. VOL. 128, NO. 26, 2006 8633

A R T I C L E S
Butterick et al.
(4) Å, 3; 2.505(4) Å, 6) bonds. This is likely due to a trans
influence of the isocyanide ligand on the cage atoms (C3, B6,
and B7) trans to it through the rhenium center. There are no
statistical differences between the C-O distances in 3, 5, and
6, nor between the C-N distances in 5 and 6. However, the
Re1-C22 (2.039(3) Å) and average Re1-C(carbonyl) (1.926-
(4) Å) distances in 6 are shorter than the corresponding Re8-
C24 (2.088(4) Å) and the average Re8-C(carbonyl) (1.959(5)
Å) distances found in the cage-slipped compound, 5. This is
likely due to the increased steric interactions of the isocyanide
ligand and three carbonyl groups in 5 compared to the
isocyanide ligand and only two carbonyl groups in 6.
In contrast to the reactions with isocyanide, the room-
temperature reactions of 2 and 3 with PMe3 and PPh3 resulted
in both phosphine addition and CO loss to form the monosub-
stituted dicarbonyl phosphine products, 7-10 (eqs 13 and
14).
Figure 7. ORTEP representation of the structure of 1,1-(CO)2-1-P(CH3)3-
2-Ph-closo-1,2,3,4-MnC3B7H9 (7). Selected distances (Å) and angles
(deg): Mn1-C2, 2.079(2); Mn1-C3, 2.013(2); Mn1-C4, 2.478(2); Mn1-
B5, 2.282(2); Mn1-B6, 2.297(2); Mn1-B7, 2.416(2); C2-C12, 1.495(2);
C2-C4, 1.506(2); C4-B7, 1.727(3); B7-C3, 1.579(3); C3-B6, 1.580(3);
B6-B5, 1.860(3); B5-C2, 1.585(3); Mn1-P18, 2.284(1); Mn1-C22,
1.769(2); C22-O23, 1.152(2); Mn1-C24, 1.826(2); C24-O25, 1.142(2);
C2-Mn1-C3, 103.7(1); Mn1-C2-C12, 123.6(1); C2-Mn1-P18, 161.9-
(1); C2-Mn1-C22, 105.1(1); C2-Mn1-C24, 82.5(1); C3-Mn1-P18,
81.2(1); C3-Mn1-C22, 120.5(1); C3-Mn1-C24, 144.4(1); Mn1-C22-
O23, 179.5(2); Mn1-C24-O25, 179.0(2).
1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MnC3B7H9 (2) + PR3 -CO8
1,1-(CO)2-1-PR3-2-Ph-closo-1,2,3,4-MnC3B7H9
[R ) Me (7), Ph (8)] (13)
1,1,1-(CO)3-2-Ph-closo-1,2,3,4-ReC3B7H9 (3) + PR3 -CO8
1,1-(CO)2-1-PR3-2-Ph-closo-1,2,3,4-ReC3B7H9
[R ) Me (9), Ph (10)] (14)
Unlike for (η5-C5H5)Mn(CO)3, the carbonyl substitution
reactions of 2 and 3 proceeded at room temperature in air,
without the need for UV irradiation. In the case of 9, reaction
was complete in 5 min, and in the case of 7, reaction was
complete in less than 5 s!
The 11B NMR spectra (Table 1) of 7-10 are similar to those
1
of 2 and 3. The H spectra of 7-10, like those of 2 and 3,
show two C-H resonances: a higher-field (2.1-2.7 ppm) peak,
consistent with a proton attached to the C4 carbon, and a lower-
field (5.1-5.6 ppm) peak coupled to phosphorus, consistent with
a proton attached to the C3 carbon.
In agreement with both the spectroscopic data and the
predicted closo electron count of their MC3B7H9 fragments,
crystallographic determinations of 7-10 confirm that the
metallatricarbadecaboranyl cages still adopt octadecahedral
geometries with the metals η6-coordinated to the puckered six-
membered face of the tricarbadecaboranyl cages (Figures 7-10).
Other than the expected longer metal-cage distances for the
rhenium compounds, the intracage distances in the tricarbade-
caboranyl ligands for the manganese complexes, 7 and 8, and
the rhenium complexes, 9 and 10, are similar. The M-B5,
M-B6, M-C2, and M-C3 distances in 7-10 (see the captions
of Figures 7-10) are much shorter than in the corresponding
compounds 2 and 3 (see the captions of Figures 2 and 3), while
the M-C4 and M-B7 bond distances are longer. As a result,
the dihedral angles between the C2-C4-B7-C3 and the C2-
M-C3 planes decrease from 62.4(1)° in 2 to 57.6(1)° in 7 and
57.2(1)° in 8 and from 61.2(1)° in 3 to 59.7(1)° in 9 and 55.8(1)°
in 10. Additionally, the metal is shifted from its position
approximately centered over the six-membered open face in 2
and 3, to a position in 7-10 where it is closer to the center of
the C2-B5-B6-C3 plane than the C2-C4-B7-C3 plane.
Probably due to steric constraints, the phosphine ligands in 7-10
are situated opposite the phenyl cage subsituent. There are only
Figure 8. ORTEP representation of the structure of 1,1-(CO)2-1-P(C5H6)3-
2-Ph-closo-1,2,3,4-MnC3B7H9 (8). Selected distances (Å) and angles
(deg): Mn1-C2, 2.080(2); Mn1-C3, 2.012(2); Mn1-C4, 2.499(3); Mn1-
B5, 2.305(3); Mn1-B6, 2.309(3); Mn1-B7, 2.419(3); C2-C12, 1.499(3);
C2-C4, 1.510(3); C4-B7, 1.726(4); B7-C3, 1.585(4); C3-B6, 1.585(4);
B6-B5, 1.857(4); B5-C2, 1.589(4); Mn1-C18, 1.842(3); C18-O19,
1.131(3); Mn1-C20, 1.771(3); C20-O21, 1.157(3); Mn1-P22, 2.313(1);
C2-Mn1-C3, 103.5(1); Mn1-C2-C12, 124.2(2); C2-Mn1-C18, 81.4-
(1); C2-Mn1-C20, 101.8(1); C2-Mn1-P22, 161.6(1); C3-Mn1-C18,
141.2(1); C3-Mn1-C20, 121.9(1); C3-Mn1-P22, 83.1(1); Mn1-C18-
O19, 177.5(2); Mn1-C20-O21, 177.7(2).
small differences among complexes 7-10 in their metal-cage
and intracage distances, even though the cone angles differ
significantly for the two phosphines (118° for PMe3 and 145°
for PPh3).33
No intermediate species were observed by 11B NMR spec-
troscopy at room temperature in the reaction of 2 with PMe3,
(33) Tolman, C. A. Chem. ReV. 1977, 77, 313-348 and references therein.
9
8634 J. AM. CHEM. SOC. VOL. 128, NO. 26, 2006

Mn and Re Tricarbadecaboranyl Tricarbonyl Complexes
A R T I C L E S
Figure 9. ORTEP representation of the structure of 1,1-(CO)2-1-P(CH3)3-
2-Ph-closo-1,2,3,4-ReC3B7H9 (9). Selected distances (Å) and angles (deg):
Re1-C2, 2.162(3); Re1-C3, 2.150(3); Re1-C4, 2.543(3); Re1-B5,
2.402(3); Re1-B6, 2.428(4); Re1-B7, 2.528(4); C2-C12, 1.493(4); C2-
C4, 1.517(4); C4-B7, 1.741(4); B7-C3, 1.596(4); C3-B6, 1.587(4); B6-
B5, 1.869(5); B5-C2, 1.609(4); Re1-P18, 2.417(1); Re1-C22, 1.873(3);
C22-O23, 1.158(4); Re1-C24, 1.939(3); C24-O25, 1.145(4); C2-Re1-
C3, 99.3(1); Re1-C2-C12, 123.0(2); C2-Re1-P18, 148.9(1); C2-Re1-
C22, 114.7(1); C2-Re1-C24, 84.0(1); C3-Re1-P18, 85.1(1); C3-Re1-
C22, 112.8(1); C3-Re1-C24, 157.0(1); Re1-C22-O23, 178.0(3); Re1-
C24-O25, 178.3(3).
Figure 11. ORTEP representation of the structure of 8,8-(CO)2-8,8-
(P(CH3)3)2-9-Ph-nido-8,7,9,10-ReC3B7H9 (11) (non-cage hydrogens have
been removed for clarity). Selected distances (Å) and angles (deg): Re8-
C9, 2.320(3); Re8-C7, 2.288(3); Re8-C10, 3.232(3); Re8-B4, 2.341(3);
Re8-B3, 2.357(3); Re8-B11, 3.265(4); C9-C12, 1.522(4); C9-C10,
1.521(4); C10-B11, 1.633(5); B11-C7, 1.608(5); C7-B3, 1.625(5); B3-
B4, 1.879(5); B4-C9, 1.648(5); Re8-P18, 2.473(1); Re8-P22, 2.455(1);
Re8-C26, 1.942(4); C26-O27, 1.155(4); Re8-C28, 1.922(3); C28-O29,
1.168(4); C9-Re8-C7, 77.7(1); Re8-C9-C12, 114.6(2); C9-Re8-P18,
94.1(1); C9-Re8-P22, 108.8(1); C9-Re8-C26, 91.5(1); C9-Re8-C28,
166.5(1); C7-Re8-P18, 77.9(1); C7-Re8-P22, 124.3(1); C7-Re8-C26,
157.2(1); C7-Re8-C28, 89.0(1); Re8-C26-O27, 176.9(3); Re8-C28-
O29, 174.8(3).
Figure 10. ORTEP representation of the structure of 1,1-(CO)2-1-P(C6H5)3-
2-Ph-closo-1,2,3,4-ReC3B7H9 (10). Selected distances (Å) and angles
(deg): Re1-C2, 2.179(3); Re1-C3, 2.127(3); Re1-C4, 2.628(3); Re1-
B5, 2.386(3); Re1-B6, 2.409(3); Re1-B7, 2.565(4); C2-C12, 1.502(4);
C2-C4, 1.518(4); C4-B7, 1.737(5); B7-C3, 1.599(5); C3-B6, 1.593(5);
B6-B5, 1.872(5); B5-C2, 1.624(4); Re1-C18, 1.957(3); C18-O19,
1.137(4); Re1-C20, 1.872(3); C20-O21, 1.166(4); Re1-P22, 2.417(1);
C2-Re1-C3, 98.2(1); Re1-C2-C12, 122.6(2); C2-Re1-C18, 82.4(1);
C2-Re1-C20, 106.8(1); C2-Re1-P22, 158.8(1); C3-Re1-C18, 146.6(1);
C3-Re1-C20, 122.2(1); C3-Re1-P22, 84.2(1); Re1-C18-O19, 176.9-
(3); Re1-C20-O21, 177.0(3).
Figure 12. ORTEP representation of the structure of 1-CO-1,1-(P(CH3)3)2-
2-Ph-closo-1,2,3,4-ReC3B7H9 (12). Although the gross geometry is con-
firmed, the observed bond distances and angles are not listed because of
disorder.
coordinated complex, 4 and is thus consistent with the formation
of the η4-coordinated intermediate, 8,8,8-(CO)3-8-(P(CH3)3)-9-
Ph-nido-8,7,9,10-MnC3B7H9. The 11B NMR spectrum and color
did not change, nor was there any gas formation noted as the
complex was warmed from -78 to -40 °C (eq 15). However,
when the temperature was increased to room temperature, this
but when the reaction was performed at -78 °C, the solution
color immediately changed from red-orange to yellow and a
new 11B NMR spectrum was observed that was different than
that of either 2 or 7. This yellow species was stable over a period
of days at -78 °C. As can be seen in Figure 13, the 11B NMR
spectrum of this intermediate is similar to that of the η4-
9
J. AM. CHEM. SOC. VOL. 128, NO. 26, 2006 8635

A R T I C L E S
Butterick et al.
Figure 13. (a) 11B NMR spectrum (taken at -40 °C) of the proposed η4-
coordinated intermediate, 8,8,8-(CO)3-8-P(CH3)3-9-Ph-nido-8,7,9,10-MnC3-
B7H9, initially formed at -78 °C in the reaction of 1,1,1-(CO)3-2-Ph-closo-
1,2,3,4-MnC3B7H9 (2) with P(CH3)3. (b) 11B NMR spectrum of the η4-
coordinated complex 8-(CNBut)-8,8,8-(CO)3-9-Ph-nido-8,7,9,10-MnC3B7H9
(4).
intermediate slowly converted to 7 with evolution of CO (eq
Figure 14. Series of 11B{1H} NMR spectra taken every 15 min over 2 h
at -40 °C of the reaction of 1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MnC3B7H9 (2)
with PMe3, showing the initial formation of the proposed η4-coordinated
intermediate, 8,8,8-(CO)3-8-P(CH3)3-9-Ph-nido-8,7,9,10-MnC3B7H9 (1),
which gradually lost carbon monoxide to produce the final η6-coordinated
product, 1,1-(CO)2-1-P(CH3)3-2-Ph-closo-1,2,3,4-MnC3B7H9 (7) (#).
16).
1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MnC3B7H9 (2) + PMe3
-78 to -40 °C8 8,8,8-(CO)3-8-(P(CH3)3)-9-Ph-nido-8,7,9,10-
MnC3B7H9 (15)
lower-field C-H resonance (2.92 ppm) and a higher-field
resonance (1.54 ppm) for each hydrogen attached to a cage
carbon.
8,8,8-(CO)3-8-(P(CH3)3)-9-Ph-nido-8,7,9,10-MnC3B7H9
-40 °C to rt 8 1,1-(CO)2-1-(P(CH3)3)-2-Ph-closo-1,2,3,4-Mn-
or -40oC, 2 h
C3B7H9 (7) + CO (16)
11 should be isoelectronic with 4 and 5, and a crystallographic
determination confirmed its predicted nido geometry, with the
formation of a five-membered, Re8-C7-B11-C10-C9, open
face. The metal is again η4-coordinated to and approximately
centered over the C7-B3-B4-C9 face of the tricarbadecabor-
anyl cage (Figure 11). The Re8-P18 (2.473(1) Å) and Re8-
P22 (2.455(1) Å) bond distances in 11 are longer than the Re1-
P18 bond distance in 9 (2.417(1) Å) due to the increased electron
donation provided by the second P(CH3)3 ligand. Because of
the change in hapticity of the tricarbadecaboranyl cage and the
formation of the Re8-C7-B11-C10-C9 open face, the
dihedral angle between the C7-Re8-C9 and C9-C10-B11-
C7 planes (25.7(2)°) in 11 is much smaller than the equivalent
dihedral angle between the C2-Re1-C3 and the C2-C4-B7-
C3 planes (59.7(1)°) in 9. This dihedral angle in 11 is also
smaller than the equivalent dihedral angle in the cage-slipped
isocyanide complexes 4 (29.4(1)°) and 5 (29.3(3)°). This is likely
due to the increased steric requirements of two P(CH3)3 ligands.
It was found that, if a solution of 8,8,8-(CO)3-8-(P(CH3)3)-
9-Ph-nido-8,7,9,10-MnC3B7H9 was maintained at -40 °C, it
slowly converted to 7. This conversion was monitored by
recording the 11B NMR spectrum of the reaction mixture
every 15 min over a 2 h period (Figure 14). As the reaction
proceeded (spectra a-i), it was noted that concurrent with the
disappearance of the peaks (1) representative of the yellow
intermediate was the formation of peaks (#) representative of
the product, 7.
Disubstitution Reactions. The disubstitution reactions of (η5-
C5H5)Mn(CO)3,34 (η5-C5Me5)Re(CO)3,35 and their derivatives
have been accomplished by photolysis of the parent complex
in the presence of the substituting ligand, but they required much
longer reaction times than the monosubstitution reactions.
On the other hand, the reaction of 9 with another equivalent
of PMe3 did not require photolysis but proceeded readily at room
temperature to produce the cage-slipped complex 11 (eq 17).
Like 5, photolysis of 11 with a slight excess of P(CH3)3
resulted in the loss of CO to form the disubstituted complex 12
(eq 18).
1,1-(CO)2-1-PMe3-2-Ph-closo-1,2,3,4-ReC3B7H9 (9) +
PMe3 f 8,8-(CO)2-8,8-(P(CH3)3)2-9-Ph-nido-
8,7,9,10-ReC3B7H9 (11) (17)
(34) Strohmeier, V. W.; Barbeau, C. Z. Naturforsh. 1962, 17b, 848-849.
(35) Bergman, R. G.; Seidler, P. F.; Wenzel, T. T. J. Am. Chem. Soc. 1985,
107, 4358-4359.
The 11B NMR spectrum (Table 1) of 11 is similar to those
of 4 and 5. The H NMR spectrum shows, as in 4 and 5, a
1
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8636 J. AM. CHEM. SOC. VOL. 128, NO. 26, 2006

Mn and Re Tricarbadecaboranyl Tricarbonyl Complexes
A R T I C L E S
8,8-(CO)2-8,8-(P(CH3)3)2-9-Ph-nido-8,7,9,10-ReC3B7H9 (11)
9
hV8 1-CO-1,1-(P(CH3)3)2-2-Ph-closo-1,2,3,4-ReC3B7H9 (12)
+ CO (18)
The 11B NMR spectrum (Table 1) of 12 is similar to that of
1
3. The H NMR spectrum shows, as in 3, a higher-field C-H
resonance for the proton attached to C4 (1.50 ppm) and a lower-
field C-H resonance for the proton attached to C3 (3.69 ppm).
The resonances for the protons attached to C3 and C4 shift
upfield on going from 3 (6.29 and 2.60 ppm) to 9 (5.06 and
2.06 ppm) and 12 (3.68 and 1.54 ppm), thus indicating an
increase in electron donation to the metal and cage system as
CO is replaced with P(CH3)3.
12 should be isoelectronic with 3, and a crystallographic
determination confirmed its predicted closo geometry (Figure
12). Unfortunately, disorder in the crystal structure prevents any
detailed analysis of bond lengths and angles.
Conclusions
Figure 15. Proposed associative mechanism for the (a) mono- and (b)
dicarbonyl substitution reactions of 1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MC3B7H9
[M ) Mn, Re] with CNBut and PR3 (R ) Me, Ph) via cage-slipped η4-
intermediates.
A possible associative mechanism for the carbonyl substitu-
tion reactions of 1,1,1-(CO)3-2-Ph-closo-1,2,3,4-MC3B7H9 [M
) Mn (2) and Re (3)], that is consistent with the results of the
crystallographic and spectroscopic studies reported herein, is
given in Figure 15a. As evidenced by both the isolation of
8-(CNBut)-8,8,8-(CO)3-9-Ph-nido-8,7,9,10-MC3B7H9 [M ) Mn
(4), Re (5)] and the observance of an 8,8,8-(CO)3-8-(P(CH3)3)-
9-Ph-nido-8,7,9,10-MnC3B7H9 intermediate species in the NMR
studies of the PMe3 substitution reaction of 2, the incoming
ligands attack at the metals before dissociation of a carbonyl
group. To maintain the 18-electron count of the resulting
complexes, the tricarbadecaboranyl ligand reduces its electron
donation to the metal from six to four electrons by the η6-η4
cage-slippage. Following carbonyl dissociation, the cage then
undergoes an η4-η6 coordination change with a concurrent
increase in electron donation to the metal center from four to
six electrons, thereby restoring the 18-electron count of the metal
in the new monosubstituted dicarbonyl complexes. Because of
the additional steric crowding, an associative reaction mecha-
nism should be less likely to be involved in the formation of
disubstituted complexes, such as 1-CO-1,1-(P(CH3)3)2-2-Ph-
closo-1,2,3,4-ReC3B7H9 (12), but even here the isolation of the
cage-slipped complex 8,8-(CO)2-8,8-(P(CH3)3)2-9-Ph-nido-
8,7,9,10-ReC3B7H9 (11) and its subsequent conversion to 12
confirms an associative reaction pathway (Figure 15b).
Other recent studies of 2 and 3 have shown that both Mn
and Re readily undergo one- and two-electron electrochemical
and chemical reductions that are also facilitated by the η6-η4
cage-slippage. The fact that one-electron reduction potentials
for 2 and 3 are each ∼1.9 V more positive of those of (η5-
C5H5)M(CO)3 [M ) Mn, Re] again illustrates that the cage-
slippage is dramatically more favorable than the η5-η3 ring-
slippage of their cyclopentadienyl counterparts.36 The ability
to readily open a vacant coordination site at the metal by such
a facile cage-slippage process may prove to be valuable in many
potential catalytic reactions of tricarbadecaboranyl metal car-
bonyl complexes. We are now exploring these possibilities.
Acknowledgment. The National Science Foundation is grate-
fully acknowledged for their support of this research.
Supporting Information Available: X-ray crystallographic
data for structure determinations of 2-12 (CIF). This material
is available free of charge via the Internet at http://pubs.acs.org.
JA062201U
(36) Nafady, A.; Geiger, W. E.; Butterick, R.; Carroll, P. J.; Sneddon, L. G.,
unpublished results.
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