Synthesis, Structure, and Reactivities of [η2-P7M(CO)4]3- , [η2-HP7M(CO)4]2- , and [η2-RP7M(CO)4]2- Zintl Ion Complexes Where M = Mo, W

Article abstract of DOI:10.1021/ic9511534

Ethylenediamine (en) solutions of [η⁴-P₇M(CO)₃]^3- ions [M = W (1a), Mo (1b)] react under one atmosphere of CO to form microcrystalline yellow powders of [η²-P₇M(CO)₄]^3- complexes [M = W (4a), Mo (4b)]. Compounds 4 are unstable, losing CO to re-form 1, but are highly nucleophilic and basic. They are protonated with methanol in en solvent giving [η²-HP₇M(CO)₄]^2- ions (5) and are alkylated with R₄N⁺ salts in en solutions to give [η²-RP₇M(CO)₄]^2- complexes (6) in good yields (R = alkyl). Compounds 5 and 6 can also be prepared by carbonylations of the [η⁴-HP₇M(CO)₃]^2- (3) and [η⁴-RP₇M(CO)₃]^2- (2) precursors, respectively. The carbonylations of 1-3 to form 4-6 require a change from η⁴- to η²-coordination of the P₇ cages in order to maintain 18-electron configurations at the metal centers. Comparative protonation/deprotonation studies show 4 to be more basic than 1. The compounds were characterized by IR and ¹H, ¹³C, and ³¹P NMR spectroscopic studies and microanalysis where appropriate. The [K(2,2,2-crypt)]⁺ salts of 5 were characterized by single crystal X-ray diffraction. For 5, the M-P bonds are very long (2.71(1) A?, average). The P₇^3- cages of 5 are not displaced by dppe. The P₇ cages in 4-6 have nortricyclane-like structures in contrast to the norbomadiene-type geometries observed for 1-3. ³¹P NMR spectroscopic studies for 5-6 show C₁ symmetry in solution (seven inequivalent phosphorus nuclei), consistent with the structural studies for 5, and C_s symmetry for 4 (five phosphorus nuclei in a 2:2:1:1:1 ratio). Crystallographic data for [K(2,2,2-crypt)]₂[η²-HP₇W(CO) ₄]·en: monoclinic, space group C2/c, a = 23.067(20) A?, b = 12.6931(13) A?, c = 21.433(2) A?, β= 90.758(7)°, V= 6274.9(10) A?³, Z = 4, R(F) = 0.0573, R_w(F²) = 0.1409. For [K(2,2,2-crypt)]₂[η²-HP₇Mo(CO) ₄]·en: monoclinic, space group C2/c, a = 22.848(2) A?, b = 12.528(2) A?,c = 21.460(2) A?, β= 91.412(12)°, V = 6140.9(12) A?³, Z = 4, R(F) = 0.0681, R_w(F²) = 0.1399.

Full text of DOI:10.1021/ic9511534

1540
Inorg. Chem. 1996, 35, 1540-1548
Synthesis, Structure, and Reactivities of [η2-P7M(CO)4]3-, [η2-HP7M(CO)4]2-, and
[η2-RP7M(CO)4]2- Zintl Ion Complexes Where M ) Mo, W
Scott Charles, James C. Fettinger, and Bryan W. Eichhorn*
Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
ReceiVed August 29, 1995X
Ethylenediamine (en) solutions of [η4-P7M(CO)3]3- ions [M ) W (1a), Mo (1b)] react under one atmosphere of
CO to form microcrystalline yellow powders of [η2-P7M(CO)4]3- complexes [M ) W (4a), Mo (4b)]. Compounds
4 are unstable, losing CO to re-form 1, but are highly nucleophilic and basic. They are protonated with methanol
in en solvent giving [η2-HP7M(CO)4]2- ions (5) and are alkylated with R4N+ salts in en solutions to give [η2-
RP7M(CO)4]2- complexes (6) in good yields (R ) alkyl). Compounds 5 and 6 can also be prepared by
carbonylations of the [η4-HP7M(CO)3]2- (3) and [η4-RP7M(CO)3]2- (2) precursors, respectively. The carbonylations
of 1-3 to form 4-6 require a change from η4- to η2-coordination of the P7 cages in order to maintain 18-electron
configurations at the metal centers. Comparative protonation/deprotonation studies show 4 to be more basic than
1. The compounds were characterized by IR and 1H, 13C, and 31P NMR spectroscopic studies and microanalysis
where appropriate. The [K(2,2,2-crypt)]+ salts of 5 were characterized by single crystal X-ray diffraction. For
3-
5, the M-P bonds are very long (2.71(1) Å, average). The P7 cages of 5 are not displaced by dppe. The P7
cages in 4-6 have nortricyclane-like structures in contrast to the norbornadiene-type geometries observed for
1-3. 31P NMR spectroscopic studies for 5-6 show C1 symmetry in solution (seven inequivalent phosphorus
nuclei), consistent with the structural studies for 5, and Cs symmetry for 4 (five phosphorus nuclei in a 2:2:1:1:1
ratio). Crystallographic data for [K(2,2,2-crypt)]2[η2-HP7W(CO)4]‚en: monoclinic, space group C2/c, a )
23.067(20) Å, b ) 12.6931(13) Å, c ) 21.433(2) Å, â ) 90.758(7)°, V ) 6274.9(10) Å3, Z ) 4, R(F) ) 0.0573,
Rw(F2) ) 0.1409. For [K(2,2,2-crypt)]2[η2-HP7Mo(CO)4]‚en: monoclinic, space group C2/c, a ) 22.848(2) Å,
b ) 12.528(2) Å, c ) 21.460(2) Å, â ) 91.412(12)°, V ) 6140.9(12) Å3, Z ) 4, R(F) ) 0.0681, Rw(F2) )
0.1399.
Introduction
The chemistry of the soluble p-block polyanions (Zintl ions)
with transition metal complexes is an emerging area of science.
Although the first reports of naked Zintl ions are now over 100
years old,1-6 the chemistry of these compounds7,8 and, in
particular, the first compounds containing Zintl ions bound to
transition metals have only recently been reported.9-17 We have
been investigating the chemistry of the E73- Zintl ions (E ) P,
As, Sb) that have the nortricyclane-like structure. In recent
papers, we and others have described the synthesis and
X Abstract published in AdVance ACS Abstracts, February 15, 1996.
characterization of the [η4-E7M(CO)3]3- complexes (1), where
(1) Joannis, A. C. R. Hebd. Seances Acad. Sci. 1891, 113, 795.
(2) Joannis, A. C. R. Hebd. Seances Acad. Sci. 1892, 114, 585.
(3) Kraus, C. A. J. Am. Chem. Soc. 1907, 29, 1557.
E ) P, As, Sb and M ) Cr, Mo, W, in which the nortricyclane-
3-
like E7 fragment is transformed into a norbornadiene-type
fragment bound η4 to the M(CO)3 center.12,18,19 The reactions
are accelerated by the use of 2,2,2-crypt “activators” that break
the K+--E73- ion pairing in solution and facilitate coordination
(4) Kraus, C. A. J. Am. Chem. Soc. 1922, 44, 1216.
(5) Zintl, E.; Harder, A. Z. Phys. Chem. Abt. A 1931, 154, 47.
(6) Zintl, E.; Goubeau, J.; Dullenkopf, W. Z. Phys. Chem. Abt. A 1931,
154, 1.
(7) von Schnering, H. G. Angew. Chem., Int. Ed. Engl. 1981, 20, 33.
(8) Corbett, J. D. Chem. ReV. 1985, 85, 383.
3-
of the E7 ion to the transition metal center (eq 1).
(9) Fritz, G.; Hoppe, K. D.; Ho¨nle, W.; Weber, D.; Mujica, C.; Manriquez,
V.; von Schnering, H. G. J. Organomet. Chem. 1983, 249, 63.
(10) von Schnering, H. G.; Wolf, J.; Weber, D.; Ramirez, R.; Meyer, T.
Angew. Chem., Int. Ed. Engl. 1986, 25, 353.
(11) Eichhorn, B. W.; Haushalter, R. C.; Pennington, W. T. J. Am. Chem.
Soc. 1988, 110, 8704.
(12) Eichhorn, B. W.; Haushalter, R. C.; Huffman, J. C. Angew. Chem.,
Int. Ed. Engl. 1989, 28, 1032.
(13) Eichhorn, B. W.; Haushalter, R. C. J. Chem. Soc., Chem. Commun.
1990, 937.
(14) Charles, S.; Eichhorn, B. W.; Bott, S. G. J. Am. Chem. Soc. 1993,
115, 5837.
(15) Fenske, D. Abstracts of Papers; 209th National Meeting of the
American Chemical Society; Anaheim, CA, 1995; American Chemical
Society: Washington, DC, 1995; INOR 299.
K3P7 + LM(CO)3 + 3(2,2,2-crypt) f
[K(2,2,2-crypt)]3[η4-E7M(CO)3] + L (1)
E ) P, As, Sb; M ) Cr, Mo, W
Molecular orbital calculations of complexes 1 show high-
lying pnictogen-based lone pairs that are localized on the E(1)
site.18,19 It is not surprising, therefore, that electrophiles such
as R+, H+, and W(CO)3Lx react with these complexes at the
E(1) site to form [η4-XE7M(CO)3]n- complexes (X ) H, R,
(16) Teixidor, F.; Leutkens, M. L., Jr.; Rudolph, R. W. J. Am. Chem. Soc.
1983, 105, 149.
(17) Baudler, M.; Etzbach, T. Angew. Chem., Int. Ed. Engl. 1991, 30, 580.
(18) Charles, S.; Bott, S. G.; Rheingold, A. L.; Eichhorn, B. W. J. Am.
Chem. Soc. 1994, 116, 8077.
(19) Bolle, U.; Tremel, W. J. Chem. Soc., Chem. Commun. 1994, 217.
0020-1669/96/1335-1540$12.00/0 © 1996 American Chemical Society

Metalated Zintl Ion Complexes
Inorganic Chemistry, Vol. 35, No. 6, 1996 1541
Scheme 1
W(CO)3). Scheme 1 summarizes the reactions of [η4-P7W-
(CO)3]3- (1a) with various electrophiles (transformations A-C)
and the nucleophile carbon monoxide (transformation D) as an
example of the chemistry of the [η4-E7M(CO)3]3- complexes.
The potent nucleophilicity of these compounds is unusual in
that extremely weak electrophiles such as R4N+ ions serve as
efficient alkylating agents in the formation of [η4-RP7W(CO)3]2-
ions, (2), at room temperature (Scheme 1, transformation A).20
In contrast to their high nucleophilicity, these compounds are
only modestly basic. For example, [η4-P7W(CO)3]3- will
deprotonate NH4+ but will not deprotonate MeOH in en or dmf.
Its conjugate acid, [η4-HP7W(CO)3]2- (3a), is efficiently depro-
tonated by MeO- in the same solvents (Scheme 1, transforma-
tion B).21
The transition metals in 1-3 have 18 valence electrons and
are not susceptible to subsequent additions of Lewis bases under
normal conditions. For example, 1-3 do not react with
phosphines or amines and are in fact prepared in neat ethyl-
enediamine solutions. However, under a carbon monoxide
atmosphere, these compounds will reversibly bind a fourth CO
ligand to form tetracarbonyl complexes (i.e. Scheme 1, trans-
formation D). In these reactions, the P7 ligand is driven from
an η4- to an η2-coordination mode in order to accommodate
the fourth CO ligand and maintain an 18 electron configuration
at the transition metal center. In this paper, we report the
synthesis, characterization, and interconversions of three types
of tetracarbonyl complexes; namely [η2-P7M(CO)4]3- and [η2-
HP7M(CO)4]2- complexes, where M ) W and Mo, and [η2-
RP7W(CO)4]2-, where R ) alkyl.22 The formation of these
compounds from the tricarbonyl precursors and their unusual
trends in relative basicities, acidities, and stabilities are also
described.
Results
Syntheses. Ethylenediamine (en) solutions of [η4-P7M-
(CO)3]3- ions [M ) W (1a), Mo (1b)] react under 1 atm of CO
to form microcrystalline powders of [η2-P7M(CO)4]3- complexes
in 71% (M ) W) and ∼18% (M ) Mo) yields (eq 2) as the
[η2-P M(CO) ]3-
M ) W (4a)
M ) Mo (4b)
[η4-P7M(CO)3]3-
+ CO a
(2)
7
4
1
[K(2,2,2-crypt)]+ salts. The [η2-P7M(CO)4]3- ions [M ) W
(4a), Mo (4b)] are bright yellow and very air and moisture
sensitive in solution and the solid state. Both compounds readily
lose one CO ligand under N2 atmospheres although the W
complex 4a is less prone to CO loss than 4b. In addition, both
compounds are more soluble but less stable in dmf than they
are in en. Because of this instability, 4b is always contaminated
by 1b impurities when under N2 and low pressures of CO.
Compounds 4 were characterized by IR, 13C and 31P NMR
spectroscopic studies and microanalysis (4a). Although we were
unable to obtain crystals suitable for a single crystal X-ray
diffraction study, spectroscopic studies clearly indicate that
complexes 4 contain an η2-P7 unit and Cs point symmetry.
Direct synthesis of 4a from W(CO)4(py)2 and P73- proceeds
very slowly at room temperature according to eq 3 and is not
an efficient synthetic route. Warming the solutions to accelerate
the reactions affects a decarbonylation of the product to form
1a. Reactions of Mo(CO)4(piperidine)2 and P73- at room temp-
erature do not give 4b but yield instead mixtures of the
protonated [η2-HP7Mo(CO)4]2- complex (5b) and the unpro-
tonated tricarbonyl 1b according to eq 4. The ratios of 5b to
1b obtained in eq 4 are dependent upon reaction conditions.
(20) Charles, S.; Fettinger, J. C.; Eichhorn, B. W. J. Am. Chem. Soc. 1995,
117, 5303.
(21) Charles, S.; Eichhorn, B. W.; Fettinger, J. C. Manuscript in preparation.
(22) The κ designations for all η4-P7 and η4-XP7 complexes (X ) R, H,
MLn) described herein are -κP4,κP5,κP6,κP7 and refer to a common
numbering scheme for the E7 units used throughout this and previ-
ous18,20,23 publications. The kappa designations for all η2-P7 and η2-
XP7 complexes (X ) R, H) described herein are -κP4,κP5 and refer to
the same common numbering scheme. For brevity, the κ designations
have been omitted in text.
(23) Charles, S.; Eichhorn, B. W.; Bott, S. G.; Fettinger, J. C. Submitted
for publication.
3-
Addition of Mo(CO)4(piperidine)2 to P7 in hot en (> ∼70

1542 Inorganic Chemistry, Vol. 35, No. 6, 1996
Charles et al.
°C) yields 1b exclusively whereas room temperature reactions
give ∼ 5:1 ratios of 5b to 1b. The formation of 1b formally
involves a loss of CO from 4b whereas 5b is a protonation
product of 4b. The actual mechanisms of these reaction
pathways and source of the proton are unknown at present.
Proteo impurities in the solvent are unlikely proton sources in
that pure unprotonated 1 and 4a can be prepared under identical
conditions.
P73- + W(CO)4(py)2 3(2,2,2-crypt)8
3- + 2py
2
[η -P7W(CO)4]
4a
(3)
P73- + Mo(CO)4(pip)2 + x“H+” 3(2,2,2-crypt)8
4
3-
2- + (1 - x)
+
x[η2-HP7Mo(CO)4]
[η -P7Mo(CO)3]
Figure 1. ORTEP drawing of the [η2-HP7Mo(CO)4]2- ion (5b). The
H atom was placed in an idealized position and was not located
crystallographically.
5b
1b
(1 - x)CO + 2pip (4)
Compounds 5 are most conveniently prepared by direct
protonation of 4 with methanol in en solvent (eq 5) but can
also be prepared by carbonylation of the [η4-HP7M(CO)3]2- ions
(3) in en as shown in eq 6. Using eq 5 chemistry, 5a can be
(instead of LiNH(CH2)2NH2) are stirred in en show unreacted
5b after 48 h at room temperature. These experiments show
that the 1b formed by deprotonating 5b with LiNH(CH2)2NH2
proceeds through 4b as outlined in eq 8 and not through 3b as
shown in eq 9. If 3b were the intermediate in the formation of
1b, the reaction with NaOMe would have been equally effective
in the preparation of 1b from 5b (i.e. MeO- readily deprotonates
3b). In addition, the corresponding tungsten chemistry yields
4a as an isolable intermediate in the deprotonation reactions.
Ethylenediamine solutions of [η4-(PhCH2)P7W(CO)3]2- (2a)
react under an atmosphere of CO to form the yellow [η2-
(PhCH2)P7W(CO)4]2- complex (6) according to eq 10. The
reaction between Me3(PhCH2)N+ and [η2-P7W(CO)4]3- also
affords 6 according to eq 11. This reaction appears to proceed
3- + MeOH f
2- + MeO-
2
[η2-P7M(CO)4]
[η -HP7M(CO)4]
4
5
(5)
2
2-
3- + CO a
(6)
[η4-HP7M(CO)3]
[η -HP7M(CO)4]
3
5
isolated as the [K(2,2,2-crypt)]2[η2-HP7W(CO)4]‚en salt in 76%
crystalline yield. Because of the lower solubility of 5b relative
to 1b, eq 4 chemistry is the most convenient route for the
preparation of [K(2,2,2-crypt)]2[η2-HP7Mo(CO)4]‚en which was
isolated in 40% crystalline yield using this method. The
compounds are golden yellow in color and moderately air and
moisture sensitive in solution and the solid state. As implied
by the equilibrium shown in eq 6, 5a and 5b slowly lose one
CO ligand under N2 atmosphere in solution but are much more
stable than 4. Compounds 5 were characterized by microanaly-
2- + CO f
[η4-(PhCH2)P7W(CO)3]
2a
[η2-(PhCH2)P7W(CO)4]2-
(10)
6
3- + Me3(CH2Ph)N+ f
[η2-P7W(CO)4]
1
ses, IR and H, 13C, and 31P NMR spectroscopic studies, and
4a
single crystal X-ray diffraction.
2- + Me3N (11)
[η2-(PhCH2)P7W(CO)4]
Unlike the tricarbonyl complexes 3 (see Scheme 1, transfor-
mation B), MeO- is not a strong enough base to deprotonate 5
in en or dmf. However, 5a is efficiently deprotonated by LiNH-
(CH2)2NH2 in en to give 4a according to eq 7. For 5b,
6
faster (t∞ e 4 h) than the alkylations reactions of 1a (t∞ ≈ 12h)
at room temperature20 (Scheme 1, path A), however, neither
reaction rates were quantitatively measured. Through the use
of eq 10 chemistry, transparent yellow crystals of 6 were isolated
in 61% yield as the [K(2,2,2-crypt)]2[η2-(PhCH2)P7W(CO)4]‚
en salt and have been characterized by microanalysis and IR
2- + NH2(CH2)2NH- f
[η2-HP7W(CO)4]
5a
3- + en (7)
[η2-P7W(CO)4]
4a
and H, 13C, and 31P NMR spectroscopic studies. Repeated
1
2- + NH2(CH2)2NH- f
[η2-HP7Mo(CO)4]
attempts to grow X-ray quality crystals were unsuccessful,
however, the spectroscopic studies show that 6 contains an η2-
P7 unit (see below) and is isostructural to the protonated analog
5. Carbonylations of other [η4-RP7W(CO)3]2- complexes where
R ) Me, Et, and n-Bu20 appear to proceed similarly but were
not studied in detail.
5b
2
3-
4
+ en f
3- + CO (8)
“[η -P7Mo(CO)4] ”
[η -P7Mo(CO)3]
4b
1b
MeO
N
2- + CO
-8
4
[η2-HP7Mo(CO)4]2- [η -HP7Mo(CO)3]
Structural Studies. The [K(2,2,2-crypt)]+ salts of the [η2-
HP7M(CO)4]2- complexes 5a and 5b are isotypic and crystallize
in space group C2/c. An ORTEP drawing of 5b is shown in
Figure 1. A summary of the crystallographic data is given in
Table 1 and a listing of selected bond distances and angles is
given in Table 2.
5b
3b
[η4-P7Mo(CO)3]
3- + MeOH (9)
1b
deprotonation with LiNH(CH2)NH2 presumably gives 4b as an
transient intermediate, however 1b is the only detectable product
(eq 8). Identical experiments in which 5b and excess NaOMe
The [η2-HP7M(CO)4]2- ions have C1 point symmetry due to
the H atom on P(1) that destroys the mirror plane observed in

Metalated Zintl Ion Complexes
Inorganic Chemistry, Vol. 35, No. 6, 1996 1543
Table 1. Crystallographic Data for [K(2,2,2-crypt)]2[η2-HP7M-
(CO)4] Where M ) Mo, W
M ) Mo
M ) W
formula
fw
space group
a, Å
b, Å
C42H81K2MoN6O16P7 C42H81K2WN6O16P7
1317.10
C2/c
22.848(2)
12.528(2)
21.460(2)
90
1405.01
C2/c
23.067(20)
12.6931(13)
21.433(2)
90
c, Å
R, deg
â, deg
91.412(12)
90
6140.9(12)
4
90.758(7)
90
6274.9(10)
4
γ, deg
V, Å3
Z
cryst dimens, mm
cryst color
D(calcd), Mg/m3
µ(Mo KR), mm-1
temp, K
2θ scan range, deg
no. of reflns colld
no. of ind reflns
data/restraints/
params
0.50 × 0.20 × 0.20
0.50 × 0.20 × 0.20
golden yellow
1.455
0.395
293(2)
2.06-22.50
4478
yellow
1.419
0.595
153(2)
Figure 2. Ball-and-stick representation of [η2-HP7W(CO)4]2- showing
the orientational disorder of the HP7 fragment in the crystal lattice.
2.57-22.50
4125
4008 [R(int) ) 0.0505] 4096 [R(int) ) 0.0220]
4008/0/357
a nortricyclane-like η2-HP7 fragment that is virtually unperturbed
from the parent anion, P73-. The metric parameters for 5a and
5b are virtually identical as illustrated in Table 2. The M-P
bonds to P(4) and P(5) average 2.71 Å and are exceedingly
long in comparison with typical M-P distances in related
zerovalent carbonyl compounds which range between 2.4 and
2.5 Å.24,25 The length of the M-P bonds does not seem to
indicate weak M-P interactions in that the clusters are not
dissociating on the NMR time scale and are not displaced by
en or dppe. The lack of correlation between M-P bond length
and bond strength was recently described.26 The M-P(6) and
M-P(7) separations are clearly nonbonding (> 3.6 Å) which
defines the η2 coordination mode of the HP7 unit. The P-P
bonds range in length from 2.15 to 2.29 Å with the longest
bonds located in the basal triangle defined by P(3), P(6), and
P(7). The P(1)-P(2) bond of 2.09(2) Å in 5a is anomalous
and may be an artifact of the orientational disorder in the crystal.
This range in bond lengths is similar to those of both the parent
anion, P73-, in Sr3P14 (2.17-2.25 Å)27 and [η4-P7Cr(CO)3]3-
(2.114-2.237 Å).18
4096/0/363
no. of ind obsd reflns 2697
2833
Fo > 4σ(Fo)
R(F)a
Rw(F2)b
∆/σ(max)
GOF
0.0681
0.0573
0.1409
e0.001
1.004
0.1399
e0.001
1.135
2
a R(F) ) ∑|Fo| - |Fc|/∑Fo. b Rw(F2) ) (∑w(|Fo - Fc|)2/∑wFo )1/2
.
the [η2-P7M(CO)4]3- complexes. However, a 2-fold disorder
of the P7 group (see Figure 2) generates a crystallographic C2
axis and C2/c crystal symmetry. In one orientation, the P7
cluster is positioned with P(2) “up” as illustrated in Figure 1
whereas the second orientation involves a 180° rotation of the
P7 cluster that leaves P(2)′ “down” (Figure 2). The two
orientations exist in a 1:1 ratio and share a common M(CO)4
fragment. The disorder was successfully modeled in both
refinements. The P-H hydrogen is most likely disordered over
four sites and was not located crystallographically.
The M-C(1) distances (2.01(3) Å, average) of the mutually
trans carbonyls are slightly longer than the M-C(2) distances
(1.92(1) Å, average) due to the higher trans influence of CO
relative to phosphorus ligands. The M-C(1) distances are typical
In contrast to the [η4-XP7M(CO)3]2- complexes where X )
H, R, M(CO)3, the [η2-HP7M(CO)4]2- structure type contains
Table 2. Selected Bond Distances (Å) and Angles (deg) for the [η2-HP7M(CO)4]2- Ions
M ) Mo
M ) W
M ) Mo
M ) W
Bonds
M-C(1)
2.025(10)
1.141(10)
2.722(6)
2.15(2)
2.148(8)
2.24(2)
2.000(13)
1.116(14)
2.691(11)
2.09(2)
2.174(13)
2.29(2)
M-C(2)
1.919(10)
1.173(10)
2.717(6)
2.190(12)
2.180(8)
2.25(2)
1.920(12)
1.178(12)
2.714(11)
2.18(2)
2.151(12)
2.29(2)
C(1)-O(1)
M-P(4)
C(2)-O(2)
M-P(5)
P(1)-P(2)
P(2)-P(4)
P(3)-P(6)
P(4)-P(5)
P(5)-P(7)
P(1)-P(3)
P(2)-P(5)
P(3)-P(7)
P(4)-P(6)
P(6)-P(7)
3.268(8)
2.169(7)
3.238(13)
2.155(12)
2.175(7)
2.195(7)
2.155(10)
2.178(9)
Angles
P(1)-P(2)-P(4)
P(1)-P(3)-P(6)
P(2)-P(1)-P(3)
P(2)-P(5)-P(7)
P(3)-P(6)-P(7)
P(3)-P(7)-P(6)
P(4)-P(6)-P(7)
P(6)-P(3)-P(7)
P(2)-P(5)-M
P(4)-M-C(1)
P(5)-M-C(1)
P(6)-P(4)-M
C(1)-M-C(1)'
C(2)-M-C(2)'
M-C(2)-O(2)
99.2(5)
99.3(10)
103.7(12)
99.8(3)
60.9(4)
60.6(4)
104.3(2)
58.5(4)
81.4(2)
83.6(3)
86.6(3)
96.8(2)
172.3(6)
87.7(5)
178.8(9)
105.4(7)
P(1)-P(2)-P(5)
P(1)-P(3)-P(7)
P(2)-P(4)-P(6)
P(3)-P(6)-P(4)
P(3)-P(7)-P(5)
P(4)-P(2)-P(5)
P(5)-P(7)-P(6)
P(2)-P(4)-M
P(4)-M-P(5)
P(4)-M-C(2)
P(5)-M-C(2)
P(7)-P(5)-M
C(1)-M-C(2)
M-C(1)-O(1)
102.5(6)
102.3(11)
99.8(3)
108.2(5)
107.7(5)
98.1(2)
104.3(3)
81.8(2)
73.86(12)
169.6(3)
169.1(3)
96.6(3)
100.8(7)
103.1(10)
102.8(10)
99.3(5)
61.6(5)
61.7(5)
104.2(4)
56.8(4)
81.9(4)
86.6(4)
84.5(4)
98.0(4)
172.6(8)
90.6(7)
175.3(12)
100.1(10)
99.3(5)
106.3(6)
105.9(6)
97.0(3)
104.3(4)
82.1(4)
73.6(2)
168.1(4)
169.0(4)
97.5(4)
91.3(5)
173(2)
91.0(4)
171.6(11)

1544 Inorganic Chemistry, Vol. 35, No. 6, 1996
Charles et al.
Figure 3. 31P NMR spectrum of [η2-P7W(CO)4]3- (4a) recorded at 25 °C and 202 MHz in dmf-d7 solution. The resonanaces marked with (*) arise
from [η2-HP7W(CO)4]2- impurities. The resonances marked with (#) arise from an unidentified impurity.
for trans carbonyls on zerovalent tetracarbonyl complexes24,25
of Mo and W whereas the M-C(2) distances are somewhat
shorter. The C(1) carbonyls are bent only slightly away from
the HP7 cage as evidenced by the C(1)-M-C(1)′ angles of
172.3(6)° for 5a and 162.6(8)° for 5b. Aside from the acute
P(4)-M-P(5) angles of 73.7° (average) that result from the
steric constraints of the HP7 fragment, the geometry at the metal
centers represent typical octahedra.
of the 65 and -3 ppm resonances indicate that they arise from
P(3) and P(2), respectively. The former resonance is unusual
in that basal phosphorus resonances are typically found upfield
of other resonances. The 13C NMR spectrum of 4a shows three
resonances between 208 and 218 ppm in a 2:1:1 integral ratio,
which is also consistent with the proposed structure. The
downfield resonance of intensity two shows P-C coupling of
13 Hz whereas the upfield resonances appear as broad singlets.
The 13C chemical shifts are downfield of the W(CO)6 (δ ) 192.1
ppm) and upfield of 1a (δ ) 231.7 ppm).
On the basis of the spectroscopic features of the [η2-P7M-
(CO)4]2- ions 4 (see below) and structural comparisons between
1, 2, and 5, it is clear that 4 contains a η2-P7 fragment and Cs
point symmetry. The mirror plane is defined by P(1), P(2),
P(3), the transition metal, and the mutually trans carbonyl
ligands as depicted in the schematic drawing shown previously.
The [η2-(PhCH2)P7W(CO)4]2- ion 6 contains seven inequiva-
lent phosphorus atoms as determined by 31P NMR spectroscopic
studies (see below) which is indicative of C1 point symmetry.
The spectroscopic similarities to 5 suggest the two are iso-
structural as implied by the schematic drawing of 6.
The 31P NMR spectra for 5 show seven equal intensity
resonances corresponding to the seven inequivalent phosphorus
atoms observed in the solid state structure (see Figure 1). The
2-D 31P-31P COSY NMR spectrum of 5b is shown in Figure
4 as an example. In the proton-coupled 31P NMR spectra, the
resonance furthest downfield [35.5 ppm (5a), 49.5 ppm (5b)]
1
shows JP-H coupling of 174 Hz, which is identical to that
observed in the 1H NMR spectra, and can therefore be assigned
to P(1). Following this assignment, one can assign all seven
resonances by way of 2-D 31P-31P COSY NMR spectroscopy.
Figure 4 shows a contour of the 2-D spectrum of 5b in which
only cross-peaks due to one-bond couplings are observed.
Therefore, the two coordinate atoms P(1), P(4), and P(5) give
resonances showing only two cross-peaks each whereas the other
four phosphorus resonances show three cross-peaks. The peak
labels shown in Figure 4 correspond to the labeling scheme used
NMR Spectroscopic Studies. The 31P NMR spectra for the
[η2-P7M(CO)4]3- ions 4 show five second-order resonances
between +65 and -127 ppm of relative intensities 1:1:1:2:2
(see Figure 3) which is the basis for the proposed solid state
structures. The mirror plane of the ion bisects two sets of
phosphorus atoms, rendering them pairwise equivalent. On the
basis of comparisons with related compounds, we propose the
following assignments. The -127 and -46 ppm resonances
of relative intensity two are assigned to the equivalent basal
phosphorus atoms and the transition-metal-bound phosphorus
atoms, respectively. The pseudotriplet-like character of the 3
ppm resonance is indicative of a two-coordinate phosphorus,
and this resonance is assigned to P(1). The splitting patterns
1
in Figure 1. The H NMR spectrum of 5a is shown in Figure
5. The P-H resonances for 5a and 5b appear as doublets of
doublets of multiplets centered at 1.78 ppm. The resonance
shows one-bond H-P coupling to P(1) of 174 Hz (average)
and two-bond coupling to P(2) of 17 Hz. Additional couplings
to the remaining phosphorus nuclei give rise to the multiplet
patterns. The 13C NMR spectra for 5 show four carbonyl
resonances, three doublets and one singlet, due to the four
inequivalent carbonyl ligands in the compounds. For both
compounds, the two downfield doublets [214.2 and 213.8 ppm
(24) Sheldrick, W. S. Chem. Ber. 1975, 108, 2242.
(25) Atwood, J. L.; Darensbourg, D. J. Inorg. Chem. 1977, 16, 2314.
(26) Ernst, R. D.; Freeman, J. W.; Stahl, L.; Wilson, D. R.; Arif, A. M.;
Nuber, B.; Ziegler, M. L. J. Am. Chem. Soc. 1995, 117, 5055.
(27) Dahlmann, W.; von Schnering, H. G. Naturwissenschaften 1972, 59,
420.
2
(5a); 222.9 and 222.3 ppm (5b)] show JP-C values of 7-10

Metalated Zintl Ion Complexes
Inorganic Chemistry, Vol. 35, No. 6, 1996 1545
Figure 6. Solid-state IR spectrum (KBr pellet) showing the P-H and
carbonyl regions of the [η2-HP7Mo(CO)4]2- ion (5b).
IR Spectroscopic Studies. The IR spectra (KBr pellet) for
4 show four ν(CO) bands between 1940 and 1743 cm-1 whereas
5 and 6 show four bands between 1969 and 1778 cm-1. These
ranges are red-shifted from the related neutral L2M(CO)4
Figure 4. 31P-31P COSY NMR spectrum for the [η2-HP7Mo(CO)4]2-
ion (5b) recorded at 27 °C and 202 MHz from dmf-d7 solution. The
resonances marked with V arise from [η4-HP7Mo(CO)3]2- impurities.
complexes (L ) phosphine) which range 2020-1870 cm-1 28,29
.
Compounds 5 also show V(PH) modes at 2239 cm-1. The V(PH)
and V(CO) regions of 5b are shown in Figure 6 as an example.
Discussion
Our initial discovery of the [η2-HP7M(CO)4]2- complexes 5
involved an attempted Mo(CO)3/W(CO)3 exchange reaction
between [η4-P7W(CO)3]3- and (cycloheptatriene)Mo(CO)3. Al-
though no exchange occurred in the absence of proteo impurities
after several days,18 in the presence of H+ the [K(2,2,2-crypt)]+
salts of [η2-HP7Mo(CO)4]2- and [η2-HP7W(CO)4]2- were
isolated as well as an ill-defined “K-Mo-P” solid state
31
compound30 with a BaVS3 related structure (eq 12). While
Figure 5. 1H NMR spectrum for the [η2-HP7W(CO)4]2- ion (5a)
recorded at 27 °C and 400 MHz from dmf-d7 solution. The singlet at
1.3 ppm is associated with the en solvate molecule.
3- + “Mo(CO)3” + H+ f
[η4-P7W(CO)3]
1a
2
[η2-HP7W(CO)4]2- [η -HP7Mo(CO)4]
+
2- + “K-Mo-P”
Hz. The upfield doublet [209.8 (5a), 214.9 (5b)] shows a larger
2JP-C value of 28.7 Hz. The fourth CO resonance is a broad
singlet for both compounds with chemical shifts of 210.7 (5a)
and 214.3 ppm (5b). The assignments and coupling constants
were confirmed by recording the spectra at different spectrom-
eter frequencies. The appearance of three doublets and one
singlet for 5 indicates that the asymmetry imparted by the proton
5a
5b
(12)
this reaction is quite reproducible, it gives inseparable mixtures
of products thus prompting us to develop the rational routes to
the complexes described herein.
The general interconversions of 1, 3, 4, and 5 are summarized
in Scheme 2. Both of the carbonylation reactions involve the
addition of a CO ligand to 18-electron, formally zerovalent metal
centers. In order to facilitate the extra CO ligand, the P7 groups
change from a 6-electron-donor η4-coordination mode to a
4-electron-donor η2-coordination mode. Like 1-3, complexes
5 and 6 are isolable and relatively stable toward CO loss in
solution and the solid state. In contrast, compounds 4 readily
lose CO under N2 atmosphere, and only the tungsten complex
4a has been prepared in a pure form.
2
on the P7 cage significantly affects the JP-C parameters.
The 31P NMR spectrum for [η2-(PhCH2)P7W(CO)4]2-, 6,
contains seven equal intensity resonances between -119 and
+120 ppm. Six of the seven resonances are within 14 ppm of
the chemical shifts of [η2-HP7W(CO)4]2-, 5a, whereas the
alkylated phosphorus P(1) resonance (δ ) 120 ppm) of 6 is
shifted 70 ppm downfield of the corresponding protonated
phosphorus resonance of 5a. The carbonyl region of the 13C
NMR spectrum shows three doublets and a broad singlet
between 215 and 210 ppm. The benzyl R-carbon resonance
For eq 2 chemistry, the reverse reaction is favored entropi-
cally, which could account for the general trend of decreased
relative stablility toward CO loss for the tetracarbonyl complexes
2
appears as a doublet at 26.9 ppm with JP-C ) 30 Hz. The
peak positions, multiplicities, and general appearance of the 31
P
and 13C NMR spectra for 6 are quite similar to those of 5a and
are the basis for the similarities in proposed structures (see
previous drawing). The 1H NMR spectrum of 5a shows
resonances between 7.3 and 7.0 ppm due to the phenyl
hydrogens of the benzyl group and “AB multiplets” at 1.83 and
1.53 ppm resulting from the diastereotopic benzyl R-hydrogens.
(28) Grim, S. O.; Briggs, W. L.; Barth, R. C.; Tolman, C. A.; Jesson, J. P.
Inorg. Chem. 1974, 13, 1095.
(29) Darensbourg, D. J.; Kump, R. L. Inorg. Chem. 1978, 17, 2680.
(30) Charles, S.; Fettinger, J. C.; Eichhorn, B. W. Results to be published.
(31) Eichhorn, B. W. In Progress in Inorganic Chemistry; Karlin, K. D.,
Ed.; John Wiley & Sons: 1994; pp 139.

1546 Inorganic Chemistry, Vol. 35, No. 6, 1996
Charles et al.
Scheme 2
relative to their tricarbonyl counterparts. However, the enhanced
relative stability of the protonated tetracarbonyl complexes 5
in comparison to the unprotonated complexes 4 is somewhat
curious. Upon protonation of the P7 cage, the C-O bond
strengths increase (higher νCO) which is usually accompanied
by a decrease in the M-C bond strengths. However, the
protonated compounds 5 are less prone to CO loss than 4. These
relative stabilities are consistent with the following two
scenarios:
in the acid-base reactions outlined in Scheme 2. Protonation
of 4 in en solutions is easily accomplished using MeOH (eq 4)
and the deprotonation of 5 requires a stronger base than MeO-
(i.e. an amide, eq 7). In contrast, protonation of 1 requires
stronger acids than MeOH (i.e. HR3N+ ions) to form 3, and
subsequent deprotonations are accomplished using MeO- (see
Scheme 2).21 The enhanced basicity and nucleophilicity of 4
can be understood through the following considerations. First,
3-
the P7 ligand is functioning as a four-electron donor in 4 vs
(1) If the tetracarbonyl complexes (4 or 5) rapidly (and
reversibly) lose CO to give η2-P7M(CO)3 16-electron intermedi-
ates, two reaction pathways can be envisaged and are shown in
eq 13. The intermediate can either coordinate CO to reform the
a six-electron donor in 1; thus the metal does not require as
much electron density from the P7 fragment in 4 relative to
3-
1. Second, the molecular orbital calculations indicate a large
3-
degree of charge transfer from the P7 ligand to the M(CO)3
fragments in the electronic structure of 1. In a limiting valence
bond model for 1, one could partition the charge in the form
P7---M(CO)32- thus making it electronically equivalent to Fe-
(CO)3(norbornadiene)32 and adequately describing the ν(CO)
energies. In contrast, the IR data for 4 show a lesser overall
charge transfer suggesting a limiting valence bond description
of P73---M(CO)4. Both of these factors could lead to enhanced
basicity and nucleophilicity of the P7 cage in 4 relative to 1.
Finally, it is of interest to note that Bolle and Tremel have
h [η2-P7M(CO)3]n- + CO f
[η2-P7M(CO)4]n-
4 or 5
[η4-P7M(CO)3]n-
1 or 3
(13)
tetracarbonyl complexes (no net reaction) or undergo a hapta-
tropic shift of the P7 ligand (η2 f η4) to form the stable
tricarbonyl compounds (1 or 3). Partitioning of products in eq
13 results from a competition between CO and the P7 cage for
the vacant coordination site at the 16-electron intermediate. The
unprotonated P7 cage of 4 is more nucleophilic and competes
more effectively with CO than does the protonated HP7 cage
of 5. The result is that the net loss of CO is faster for 4 than
5.
investigated similar reactions between Sb73- and Mo(CO)4(bipy)
3-
which gave low yields of Sb11 and [η4-Sb7Mo(CO)3]3- 19,33
.
Formation of the latter compound most likely proceeds through
an unstable [η2-Sb7Mo(CO)4]3- intermediate similar to 4. Our
attempts to isolate this intermediate and the [η2-Sb7W(CO)4]3-
analog are in progress.
(2) Alternatively, the haptatropic shift could be part of a
concerted nucleophilic displacement of a CO ligand to form
the tricarbonyl complexes without pre-dissociation of CO. In
this case, the relative nucleophilicities of the protonated vs
unprotonated P7 cages would still give rise to the same relative
stabilities of 4 vs 5.
Experimental Section
General Data. General operating procedures used in our laboratory
have been described elsewhere.18 Proton (1H) NMR spectra were
recorded at ambient temperature on a Bruker AM400 (400.136 MHz)
spectrometer. Carbon (13C) NMR spectra were recorded at ambient
temperature on Bruker AF200 (50.324 MHz) and Bruker AM400
(100.614 MHz) spectrometers. Some of the 13C NMR chemical shifts
and couplings were confirmed by recording the spectra at different
magnetic field strengths. Phosphorus (31P) NMR spectra were recorded
on Bruker WP200 (81.015 MHz) and AMX500 (202.458 MHz)
spectrometers. The 31P-31P COSY NMR experiment was conducted
on an AMX500.
In either scenario, the unprotonated P73- ligand of 4 is more
nucleophilic than the protonated HP72- cage of 5 and will faVor
formation of the tricarbonyl complexes (CO loss).
The series of compounds also show unusual trends in basicity
and nucleophilicity. For example, addition of a CO ligand to
1 in the formation of 4 increases the basicity and nucleophilicity
of the coordinated P7 cage. These enhancements are evidenced
qualitatively by the faster alklyation reactions of 4 (i.e. eq 11)
relative to 1 (i.e. transformation A, Scheme 1) and quantitatively
(32) Albright, T. A.; Burdett, J. K.; Whangbo, M.-H. Orbital Interactions
in Chemistry; John Wiley & Son, Inc.: New York, 1985, pp 218.
(33) Bolle, U.; Tremel, W. J. Chem. Soc., Chem. Commun. 1992, 91.

Metalated Zintl Ion Complexes
Inorganic Chemistry, Vol. 35, No. 6, 1996 1547
The following is a list of observed data common to all compounds
containing [K(2,2,2-crypt)]+. IR (KBr pellet), cm-1: 3126 (m), 2957
(m), 2885 (m), 2817 (m), 1655 (m), 1597 (w), 1476 (m), 1459 (m),
1444 (m), 1400 (m), 1387 (s), 1362 (s), 1354 (s), 1299 (m), 1260 (m),
1238 (w), 1173 (w), 1132 (s), 1103 (s), 1081 (s), 1059 (m), 1030 (w),
950 (m), 933 (m), 830 (m), 820 (w), 806 (m), 754 (w), 667 (m), 638
(w), 614 (w), 572 (w), 546 (w), 525 (w). 1H NMR (dmf-d7), δ (ppm):
3.61 (s, 2,2,2-crypt), 3.58 (t, 2,2,2-crypt), 2.57 (t, 2,2,2-crypt), 2.54 (s,
en), 1.26 (bs, en). 13C{1H} NMR (dmf-d7), δ (ppm): 70.97 (s, 2,2,2-
crypt), 68.34 (s, 2,2,2-crypt), 54.56 (s, 2,2,2-crypt), 46.28 (s, en).
Chemicals. The preparation of the K3P7 has been previously
reported.18 Caution! Alkali metal polyphosphorus compounds are
known to spontaneously detonate even under rigorously anaerobic
conditions.34 These materials should only be prepared in small
quantities and should be handled with caution. (Cycloheptatriene)-
molybdenum tricarbonyl, (mesitylene)tungsten tricarbonyl, tetracarbo-
nylbis(piperidine)molybdenum, benzyltrimethylammonium bromide,
and 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (2,2,2-
crypt) were purchased from Aldrich and used without further purifica-
tion. Ethylenediamine (en) was purchased from Fisher (Anhydrous),
distilled several times from CaH2 under N2 and then from K4Sn9 at
reduced pressure, and finally stored under N2. Dimethylformamide
(dmf) was purchased from Burdick & Jackson (High Purity), degassed,
distilled at reduced pressure from K4Sn9, and stored under N2. Carbon
monoxide (CO) was purchased from Air Products and used without
further purification. dmf-d7 was purchased from Cambridge Isotope
Laboratories and used without further purification. The preparation
of [K(2,2,2-crypt)]3[η4-P7M(CO)3]‚en (M ) Mo, W) and [K(2,2,2-
crypt)]2[η4-(CH2Ph)P7W(CO)3]‚en have previously been reported.18,20
Syntheses. Preparation of [K(2,2,2-crypt)]3[η2-P7Mo(CO)4]. In
a 25 mL Schlenk flask, crystalline [K(2,2,2-crypt)]3[η4-P7Mo(CO)3]‚
en (114 mg, 0.067 mmol) was dissolved in en (∼ 3 mL) yielding a red
solution. The head gases were removed under vacuum and the flask
back filled with CO (∼ 1 atm). The flask was left open to the bubbler
with a flow of CO for 30 s. The reaction mixture was vigorously stirred
under a CO atmosphere for 12 h producing a yellow-orange solution
and yellow-orange powder. The mother liquor was removed, the
yellow-orange powder washed with tol and dried under vacuum (powder
yield, 57 mg). IR spectroscopic analysis of the powder showed 5b
contaminates and 31P NMR spectroscopic analysis of the mother liquor
cm-1: 2238 (w), 1969 (s), 1854 (s), 1831 (s), 1783 (s). 1H NMR (dmf-
d7), δ (ppm): 1.78 (ddm, J(H,P) ) 172 Hz, J(H,P) ) 16.7 Hz). 13C
{1H} NMR (dmf-d7), δ (ppm): 222.9 (d, 2J(C,P) ) 11 Hz, CO), 222.3
(d, 2J(C,P) ) 10 Hz, CO), 214.9 (d, 2J(C,P) ) 28.7 Hz, CO), 214.3 (br
s, CO). 31P{1H} NMR (dmf-d7), δ (ppm): 35.5 (m, 1 P), -18.5 (m,
1 P), -31.5 (m, 1 P), -55.0 (m, 1 P), -74.0 (m, 1 P), -106.0 (m, 1
P), -118.0 (m, 1 P).
1
2
Preparation of [K(2,2,2-crypt)]2[η2-HP7W(CO)4]‚en. Method A.
In a 25 mL Schlenk flask, 0.089 mmol of [K(2,2,2-crypt]3[η2-P7W-
(CO)4]‚en were generated in situ as described above (Method A). The
powder was not isolated from the mother liquor. Instead, methanol
(10 µL) was added under a flow of CO and the mixture stirred
vigorously for 8 h under a CO atmosphere. The color of the solution
remained yellow. After stirring, the mother liquor was removed leaving
a yellow, powdery solid that was washed with toluene and dried under
vacuum (powder yield, 96 mg, 76%).
Method B. In a 25 mL Schlenk flask, crystalline [K(2,2,2-crypt)]2-
[η4-HP7W(CO)3]‚en (41 mg, 0.031 mmol) was dissolved in en (∼2
mL) yielding a dark red solution. The head gases were removed under
vacuum and the flask back filled with CO (∼1 atm). The flask was
left open to the bubbler with a flow of CO for 30 s. The reaction
mixture was vigorously stirred under a CO atmosphere for 12 h,
producing a yellow solution and yellow powder. 31P NMR spectro-
scopic analysis of the mother liquor showed quantitative yield of 3b.
Anal. Calcd for C42H81N6O16K2P7W: C, 35.91; H, 5.81; N, 5.98.
Found: C, 35.37; H, 5.64; N, 5.96. IR data (KBr pellet), cm-1: 2240
(w), 1964 (s), 1843 (s), 1825 (s), 1778 (s). 1H NMR (dmf-d7), δ
1
2
(ppm): 1.78 (ddm, J(H,P) ) 172 Hz, J(H,P) ) 16.7 Hz). 13C {1H}
NMR (dmf-d7), δ (ppm): 214.8 (d, 2J(C,P) ) 10.8 Hz, CO), 213.8 (d,
2J(C,P) ) 10.8 Hz, CO), 210.7 (br s, CO), 209.8 (d, J(C,P) ) 28.7
2
Hz, CO). 31P{1H} NMR (dmf-d7), δ (ppm): 49.5 (m, 1 P), -9.3 (m,
1 P), -24.2 (m, 1 P), -54.7 (m, 1 P), -71.3 (m, 1 P), -106.2 (m, 1
P), -116.0 (m, 1 P).
Preparation of [K(2,2,2-crypt)]2[η2-(CH2Ph)P7W(CO)4]‚en. Method
A. In a vial in a drybox, K3P7 (29.6 mg, 0.089 mmol), 2,2,2-crypt
(100.0 mg, 0.27 mmol) and (C6H3Me3)W(CO)3 (34.4 mg, 0.089 mmol)
were combined in en (∼ 3 mL) and stirred for 12 h producing a red
solution. Solid (PhCH2)Me3NBr (20.5 mg, 0.089 mmol) was added
and the reaction mixture stirred for an additional 12 h yielding a maroon
solution. The reaction mixture was transferred from the vial to a 25
mL Schlenk flask, and the head gases were removed under vacuum.
The Schlenk flask was then backfilled with CO (∼1 atm) and the flask
left open to the bubbler with a flow of CO for 30 s. The reaction
mixture was vigorously stirred under a CO atmosphere for 12 h,
producing a yellow solution and yellow powder. The mother liquor
was removed, yielding a yellow powder that was washed with tol and
dried under vacuum (powder yield, 81 mg, 61%).
showed both 1b and 5b contaminates. IR data (KBr pellet), cm-1
:
1943 (s), 1830 (s), 1799 (s), 1748 (s). 31P NMR (dmf-d7), δ (ppm):
60 (m, 1 P), -11 (dd, 1 P), -16 (m, 1 P), -53 (m, 2 P), -130 (m, 2
P).
Preparation of [K(2,2,2-crypt)]3[η2-P7W(CO)4]‚en. In a 25 mL
Schlenk flask, K3P7 (29.6 mg, 0.089 mmol), 2,2,2-crypt (100.0 mg,
0.27 mmol) and (C6H3Me3)W(CO)3 (34.4 mg, 0.089 mmol) were
combined in en (∼ 3 mL). The reaction mixture was stirred for 12 h
yielding a red solution. The head gases were removed under vacuum
and the flask backfilled with CO (∼1 atm). The flask was left open to
the bubbler with a flow of CO for 30 s. The reaction mixture was
vigorously stirred under a CO atmosphere for 12 h, producing a yellow
solution and yellow powder. The mother liquor was removed and the
yellow powder washed with tol and dried under vacuum (powder yield,
115 mg, 71%). Anal. Calcd for C60H116N8O22K3P7W: C, 39.61; H,
6.43; N, 6.16. Found: C, 39.79; H, 6.25; N, 6.31. IR data (KBr pellet),
cm-1: 1939 (s), 1819 (s), 1793 (s), 1744 (s). 13C{1H} NMR (dmf-d7),
δ (ppm): 218.1 (d, J(C,P) ) 13 Hz, CO), 214.5 (br s, CO), 211.6 (br
s, CO). 31P NMR (dmf-d7), δ (ppm): 65 (m, 1 P), 3 (dd, 1 P), -3 (m,
1 P), -46 (m, 2 P), -127 (m, 2 P).
Method B. [K(2,2,2-crypt)]3[η2-P7W(CO)4]‚en (0.089 mmol) was
prepared as described above (Method A). Solid (PhCH2)Me3NBr (20.5
mg, 0.089 mmol) was added to the solution and the reaction mixture
stirred for 8 h. 31P NMR spectroscopic analysis of the mother liquor
showed quantitative conversion to 3c. Anal. Calcd for C49H88-
N6O16K2P7W: C, 39.34; H, 5.93; N, 5.62. Found: C, 38.50; H, 5.69;
N, 5.44. IR data (KBr pellet), cm-1: 1964 (s), 1840 (s), 1824, (s),
1774 (s). 1H NMR (dmf-d7), δ (ppm): 7.3-7.0 (m, CH2Ph), 1.83,
1.53 (CH2Ph). 13C{1H} NMR (dmf-d7), δ (ppm): 215 (m, CO), 214
2
(m, CO), 211 (br s, CO), 210 (d, J(C,P) ) 30 Hz), CO), 143.8 (br s,
1
ipso C), 130, 128, 125 (CH2Ph), 26.9 (d, J(C,P) ) 30 Hz, CH2Ph).
31P{1H} NMR (dmf-d7), δ (ppm): 120 (m, 1 P), -1 (m, 1 P), -38 (m,
1 P), -58 (m, 1 P), -80 (m, 1 P), -119 (m, 2 P).
Preparation of [K(2,2,2-crypt)]2[η2-HP7Mo(CO)4]‚en. In a vial
in a drybox, K3P7 (29.6 mg, 0.089 mmol), 2,2,2-crypt (100.0 mg, 0.27
mmol), and (C5H10NH)2Mo(CO)4 (33.7 mg, 0.089 mmol) were dissolved
in en (∼2 mL) and gently stirred for 3 h, yielding a red-orange solution.
The reaction mixture was filtered through ca. one quarter inch of tightly
packed glass wool in a pipet. After 24 h, the reaction vessel contained
rectangular yellow-orange crystals that were removed from the mother
liquor, washed with toluene, and dried under vacuum (crystalline yield,
47 mg, 40%). Anal. Calcd for C42H81N6O16K2P7Mo: C, 38.30; H,
6.20; N, 6.38. Found: C, 37.42; H, 5.89; N, 6.07. IR data (KBr pellet),
Reaction of [η4-P7W(CO)3]3- and “Mo(CO)3”. In vial 1 in a
drybox, K3P7 (29.6 mg, 0.089 mmol), 2,2,2-crypt (100.0 mg, 0.27
mmol), and (C6H3Me3)W(CO)3 (34.4 mg, 0.089 mmol) were dissolved
in en (∼ 3 mL) and stirred for 12 h producing a red solution. In vial
2, (C7H8)Mo(CO)3 (24.1 mg, 0.089 mmol) was suspended in toluene
(∼1 mL) and then added dropwise to the contents of vial 1. The
mixture was stirred for 2 h without a change in the red color of the
solution. After 24 h, the reaction vessel contained golden yellow
crystals that were removed from the mother liquor, washed with toluene,
and dried under vacuum (crystalline yield, 46 mg). A crystal of
[K(2,2,2-crypt)]2[η2-HP7W(CO)4]‚en was selected for single-crystal
X-ray diffraction study. IR and 31P NMR spectroscopic analysis of
(34) von Schnering, H. G.; Ho¨nle, W. Chem. ReV. 1988, 88, 243.

1548 Inorganic Chemistry, Vol. 35, No. 6, 1996
Charles et al.
the crystals revealed 5a and 5b in a 10:1 ratio. Visual inspection of
the crystals also showed five that were red in color. Single crystal
X-ray diffraction revealed a “K-Mo-P” compound with a BaVS3-
type structure.30
relation coefficients indicated that the atoms comprising the main
molecule were strongly influencing one another, indicating that the true
space group was C2/c. SHELXL was used to refine the structure, based
2
2
upon Fo and σ(Fo ). The function minimized during the full-matrix
Attempts at Deprotonation. Solutions of [η2-HP7M(CO)4]2- (M
) Mo, W) (0.089 mmol) were prepared in Schlenk flasks as described
above (Method A for 5a). Solid NaOMe (7.2 mg, 0.134 mmol) or
solid H2N(CH2)2NHLi (8.9 mg, 0.134 mmol) were added and the
reaction mixtures stirred for 8 h. The products were then assayed by
31P NMR spectroscopy.
least-squares refinement was ∑w(Fo - Fc2) where w ) 1/[σ2(Fo ) +
2
2
(0.0869P)2] and P ) (max(Fo ,0) + 2Fc2)/3. Hydrogen atoms were
2
placed in calculated positions but not refined. A final difference-Fourier
map was featureless with |∆F| e 0.673 e Å-3
.
[K(2,2,2-crypt)]2[η2-HP7Mo(CO)4]‚en. A procedure identical to
that described above was used for the isomorphic [K(2,2,2-crypt)]2-
[η2-HP7Mo(CO)4]‚en complex. Data were collected [MoKR] with ω/2θ
scans over the range 2.4-22.5°. The data were not corrected for
absorption or decay. The structure was determined with isomorphous
replacement based upon a previous [K(2,2,2-crypt)]2[η2-HP7Mo(CO)4]‚
en study. The final difference-Fourier map was featureless with |∆F|
X-ray Crystallographic Studies. [K(2,2,2-crypt)]2[η2-HP7W-
(CO)4]‚en. A yellow colored crystal with dimensions 0.50 × 0.20 ×
0.20 mm was placed on the Enraf-Nonius CAD-4 diffractometer. The
crystal’s final cell parameters and crystal orientation matrix were
determined from 25 reflections in the range 18.1 < 2θ < 33.5°; these
constants were confirmed with axial photographs. Data were collected
[MoKR] with ω/2θ scans over the range 2.0-22.5° with a scan width
of (0.90 + 0.35 tan θ)° and a variable scan speed of 2.06-4.12° min-1
with each scan recorded in 96 steps with the outermost 16 steps on
each end of the scan being used for background measurement. Three
ψ-scan reflections were collected twice over the range 8.1 < θ < 13.0°;
the absorption correction was applied with transmission factors ranging
from 0.8086 to 0.9994 with an average correction of 0.9315.
Data were corrected for Lorentz and polarization factors and
absorption and reduced to observed structure-factor amplitudes using
the program package NRCVAX. Systematic absences indicated the
centrosymmetric space group C2/c (No. 15) or the noncentrosymmetric
space group Cc (No. 9). Intensity statistics were inconclusive although
slightly favoring the acentric case. The structure was determined with
the successful location of the tungsten and seven phosphorus atoms
using SHELXS-86 in the acentric space group Cc. Subsequent
difference-Fourier maps revealed the location of all remaining non-
hydrogen atoms within the molecule and two K‚crypt ligands. Cor-
e 0.848 e Å-3
.
Acknowledgment. This work was funded by the National
Science Foundation through Grant CHE-9500686. We grate-
fully acknowledge Prof. Rinaldo Poli for helpful discussions.
Supporting Information Available: A complete listing of crystal-
lographic data positional parameters, thermal parameters, bond distances
and angles, a table showing the conversion from the text numbering
scheme to that used in the Supporting Information, and ORTEP
diagrams of the anions showing the numbering scheme used in the
Supporting Information for [K(2,2,2-crypt)]2[η2-HP7M(CO)4] where M
) Mo, W (23 pages). This material is contained in many libraries on
microfiche, immediately follows this article in the microfilm version
of the journal, and can be ordered from the ACS; see any current
masthead page for ordering information.
IC9511534