Syntheses, structures, and VT NMR studies of diselenophosphates of group 14 organometals. DFT calculations for gas-phase stability of dinuclear ions, [(Ph3M)2{μ-Se, Se-P(OR)2}]+(M = Ge, Sn, and Pb)

Article abstract of DOI:10.1021/om050291q

Equimolar reactions of group 14 compounds, (C₆H ₅)₃MCl with (NH₄)[Se₂P(OR) ₂], in diethyl ether yielded the first organometallic derivatives of diselenophosphates, viz., [Ph₃M{η<

Full text of DOI:10.1021/om050291q

4072
Organometallics 2005, 24, 4072-4078
Syntheses, Structures, and VT NMR Studies of
Diselenophosphates of Group 14 Organometals. DFT
Calculations for Gas-Phase Stability of Dinuclear Ions,
[(Ph3M)2{µ-Se, Se-P(OR)2}]+(M ) Ge, Sn, and Pb)
C. W. Liu,*,† Tarlok S. Lobana,‡,| Jie-Liang Xiao,‡ Hong-Yuan Liu,‡
Ben-Jie Liaw,‡ Chiu-Ming Hung,‡ and Zhenyang Lin*,§
Department of Chemistry, National Dong Hwa University, Hualien 974, Taiwan,
Department of Chemistry, Chung Yuan Christian University, Chung-Li 320, Taiwan, and
Department of Chemistry, Hong Kong University of Science and Technology,
Clear Water Bay, Kowloon, Hong Kong
Received April 16, 2005
Equimolar reactions of group 14 compounds, (C6H5)3MCl with (NH4)[Se2P(OR)2], in diethyl
ether yielded the first organometallic derivatives of diselenophosphates, viz., [Ph3M{η1-Se
i
n
i
n
i
n
(Se)P(OR)2}] [M) Ge, R ) Et, Pr, Pr (1-3); Sn, Et, Pr, Pr (4-6); Pb, Et, Pr, Pr (7-9)].
The crystal structures of 1, 4, 6, and 7 showed that the geometry around a metal center for
each compound is distorted tetrahedral. The (η1-Se) coordination mode with one pendant Se
atom exhibited in these complexes is the new connective pattern for the diselenophosphates.
31P and 77Se NMR spectral studies reveal that whereas germanium compounds do not show
lability of Ge-Se bonds, the Sn and Pb compounds do exhibit lability of Sn-Se and Pb-Se
bonds, which involve exchange of the coordinated and pendant Se atoms at room temperature.
This exchange process is slowed at low temperature and stopped at around 210 K. The
exchange energy (∆Gq) is calculated to be in the range of 38-46 kJ mol-1 for compounds
4-9. Positive FAB-mass spectral data reveal that germanium compounds 1 and 3 have nearly
equal abundance of molecular ions [(Ph3M){µ-Se, Se-P(OR)2}]+ and dinuclear cations [(Ph3M)2-
{µ- Se, Se-P(OR)2}]+; the same is not true for tin and lead compounds 4, 5, 7, and 8, whose
dinuclear cations are several times intense over their molecular ions. The structures of these
dinuclear cations as well as their formation pathway have been studied by the density
functional theory calculations.
Introduction
and by preparing several unusual clusters and poly-
nuclear compounds.10-23 There are only two structurally
characterized compounds among elements other than
groups 11-13, namely, [Mo3(µ3-Se)(µ2-Se2)3{Se2P(OEt)2}3]-
(Br)5 and Ni[Se2P(OEt)2]2.7 In sharp contrast, many
Diselenophosphates [dsep, Se2P(OR)2-] have been
known since 1968, but their coordination chemistry
remained ignored, probably because of their oxidation
and extrusion of Se from the ligand.1-9 In the past
decade Liu et al. have demonstrated the novelty of
diselenophosphates by studying their coordination chem-
istry, particularly with elements from groups 11-13,
(10) Liu, C. W.; Chen, H.-C.; Wang, J.-C.; Keng, T.-C. Chem.
Commun. 1998 1831.
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Commun. 1999, 995.
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C.; Guo, K.-M. Chem. Commun. 2000, 1897.
* To whom correspondence should be addressed. Fax: (+886)-3-
8633570. E-mail: chenwei@mail.ndhu.edu.tw.
† National Dong Hwa University.
(13) Liu, C. W.; Chen, H.-C.; Wang, J.-C.; Keng, T.-C. Angew. Chem.,
Int. Ed. 2001, 40, 2342.
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J. Chem. Soc., Dalton Trans. 2002, 1974.
‡ Chung Yuan Christian University.
§ Hong Kong University of Science and Technology.
| On leave from Guru Nanak Dev University, Amritsar 143005, India
(tarlokslobana@yahoo.co.in).
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Dalton Trans. 2002, 3482.
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H.-H.; Inorg. Chem. 2003, 42, 3216.
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10.1021/om050291q CCC: $30.25 © 2005 American Chemical Society
Publication on Web 06/28/2005

Diselenophosphates of Group 14 Organometals
Organometallics, Vol. 24, No. 16, 2005 4073
Chart 1
studies on compositions and structures of complexes of
analogous phosphor-1,1-dithiolate ligands have been
reported.24-34
Figure 1. Thermal ellipsoid drawing (30% probability) of
[(C6H5)3Ge{η1-Se (Se)P(OEt)2}], 1, with atomic numbering
scheme.
Four coordination modes of diselenophosphates have
been identified in their metal complexes (II-V, Chart
1),1-23 and mode I is being reported for the first time in
this paper. In view of our interest to develop coordina-
tion chemistry of diselenophosphates as ligands and also
after finding very interesting polynuclear complexes
with CuI, AgI, and ZnII,10-22 we were curious to look into
main group elements. In this respect, indium(III) formed
octahedral, tris-chelated complexes, In[Se2P(OR)2]3, which
in solution state showed lability of the In-Se bonds,23
and in order to explore the generality of this observa-
tion, we were interested in investigating the interaction
of dsep ligands with group 14 metals. Tin(II) and lead-
(II) were known to form M[Se2P(OEt)2]2 (M ) Sn, Pb),2
but the synthesis and structural chemistry of tin(IV)
and lead(IV) are unexplored. In this paper, the synthe-
sis, multinuclear NMR spectroscopy, positive FAB mass,
and crystal structures (1, 4, 6, and 7) of diselenophos-
phate derivatives of organogermanium(IV), tin(IV), and
lead(IV) are reported. The chemistry of related dithio-
phosphates with organogermanium(IV), tin(IV), and
lead (IV) has been reported.35-44 The solution-state
fluxionality of tin and lead complexes as well as gas-
phase stability of dinuclear ions, such as [(Ph3M)2{µ-
Se, Se-P(OR)2}]+ (M ) Ge, Sn, Pb) are the interesting
features of the studies. The exchange of free energy
between coordinated and pendant Se donor atoms is also
calculated for the tin and lead compounds. DFT calcula-
tions for dinuclear cations and molecular complexes are
also carried out.
Results and Discussion
Synthesis. Equation 1 depicts the formation of
compounds 1-9, obtained by a metathetical reaction of
Ph3MCl (M ) Ge, Sn, Pb) with a dsep ligand.
Ph3MCl + (NH4)[Se2P(OR)2] N , 0 °C8
2
Et2O
Ph3M[Se(Se)P(OR)2] + NH4Cl (1)
M ) Ge, R ) Et (1), iPr (2), nPr (3)
Sn, R ) Et (4), iPr (5), nPr (6)
Pb, R ) Et (7), iPr (8), nPr (9)
(24) Haiduc, I.; Edelmann, F. T. Supramolecular Organometallic
Chemistry; Wiley: Weinheim, New York, 1999.
(25) (a) Haiduc, I.; Sowerby, D. B.; Lu, S.-F. Polyhedron 1995, 14,
3389. (b) Haiduc, I. In Comprehensive Coordination Chemistry II;
McCleverty, J. A., Meyer, T. J., Eds.; Elsevier: Amstredam, 2003; Vol.
1, pp 349-376.
The yields were around 80-90%; compounds of Sn
and Pb are stable to air and moisture, but those of Ge
(26) Haiduc, I.; Sowerby, D. B. Polyhedron 1995, 14, 2469 and
references therein.
45
involve reaction with oxygen to form Ph3Ge-O-GePh3
(27) Wasson, R.; Woltermann, G. M.; Stoklosa, H. J. Fortschr. Chem.
Forsch. (Top. Curr. Chem.) 1973, 35, 65.
and (RO)2P(Se)-Se-Se-P(Se)(OR)2. They are soluble in
common solvents such as CH2Cl2, CHCl3, acetone, etc.
The compounds were characterized by their elemental
analysis, FAB-mass, and X-ray crystallography for 1,
4, 6 and 7. The solution-state behavior of all complexes
was studied by using multinuclear NMR (1H, 31P, 77Se)
spectroscopy.
X-ray Structures. The crystal structures of com-
pounds 1, 4, 6, and 7 confirm the stoichiometry of all of
the complexes as [Ph3M{η1-Se(Se)P(OR)2}] (M ) Ge, Sn,
Pb), and they are isostructural. The atomic numbering
scheme for compound 1 is shown in Figure 1. In
(28) Mehrotra, R. C.; Srivastava, G.; Chauhan, B. P. S. Coord. Chem.
Rev. 1984, 55, 207.
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(32) Liu, C. W.; Stubs, R. T.; Staples, R. J.; Fackler, J. P., Jr. J.
Am. Chem. Soc. 1995, 117, 9778.
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3899.
(34) Fackler, J. P. Jr.; Staples, R. J.; Liu, C. W.; Stubs, R. T.; Lopez,
C.; Pitts, J. T. Pure Appl. Chem. 1998, 70, 839.
(35) Rao, R. J. Phosphorus, Sulfur Silicon Relat. Elem. 1990, 53,
203.
(36) Clark, H. C.; Jain, V. K.; Mehrotra, R. C.; Singh, B. P.;
Srivastava, G.; Birchall, T. J. Organomet. Chem. 1985, 279, 385.
(37) Rao, R. J.; Srivastava, G.; Mehrotra, R. C. J. Organomet. Chem.
1983, 258, 155.
(42) Chadha, R. K.; Drake, J. E.; Sarkar, A. B. Inorg. Chem. 1985,
24, 3156.
(43) Molloy, K. C.; Hossain, M. B.; van der Helm, D. Zuckerman, J.
J.; Haiduc, I. Inorg. Chem. 1979, 18, 3507.
(44) Preut, H.; Ngo, V. D.; Huber, F. Acta Crystallogr. 1987, C43,
164.
(45) (a) Glidewell, C.; Liles, D. C. Acta Crystallogr. Sect B: Struct.
Sci. 1978, 34, 119.(b) Kuzmina, L, G. Struchkov, Yu. T. J. Struct. Chem.
1972, 13, 946.
(38) Lefferts, J. L.; Molloy, K. C.; Zuckerman, J. J.; Haiduc, I.; Guta,
C.; Ruse, D. Inorg. Chem. 1980, 19, 1662.
(39) Singh, B. P.; Srivastava, G.; Mehrotra, R. C. J. Organomet.
Chem. 1979, 171, 35.
(40) Begley, M. G.; Gaffney, C.; Harrison, P. G.; Steel, A. J.
Organomet. Chem. 1985, 289, 281.
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Inorg. Met.-Org. Chem. 1975, 5, 103.

4074 Organometallics, Vol. 24, No. 16, 2005
Liu et al.
Table 1. Selected Bond Lengths (Å) and Angles
(deg) for Compounds 1, 4, 6, and 7
coordinated and pendant Se donor atoms. The coordi-
1
nated Se atom showed JP-Se coupling constant of 527
1
Hz, while the pendant Se showed 1JP-Se of 876 Hz, and
the same trend was shown by compounds 2 and 3. The
77Se NMR spectrum showed two doublets for each of the
compounds 1-3; the substituents affect the chemical
shift as expected, and for the coordinated Se, the order
Ge(1)-C(17)
Ge(1)-C(5)
Ge(1)-C(11)
1.933(6) Ge(1)-Se(1)
1.943(6) Se(1)-P(1)
1.947(6) Se(2)-P(1)
2.4050(9)
2.2190(17)
2.0775(17)
C(5)-Ge(1)-C(11) 110.3(2)
C(17)-Ge(1)-C(11) 112.0(2)
C(17)-Ge(1)-C(5) 112.4(2)
C(17)-Ge(1)-Se(1) 109.95(18)
C(5)-Ge(1)-Se(1) 112.19(16)
C(11)-Ge(1)-Se(1) 99.31(16)
i
n
of chemical shift to low field varied as Pr . Pr ≈ Et.
There is an irregular trend in pendant Se donor atoms.
Lability of Sn-Se and Pb-Se Bonds. One of the
most interesting features of the present investigations
is the observation of fluxionality of Sn-Se and Pb-Se
bonds at room temperature and the lack of it in the case
of the Ge-Se bonds. The 31P NMR of compound 4 at
room temperature showed one singlet at δ 70.1 ppm and
two pairs of satellites. One pair of satellites is due to
31P-77Se coupling (1JP-Se, 695 Hz), and the second pair
is due to 31P-119Sn coupling (2JP-Sn, 59.1 Hz). As noted
for germanium, there were two pairs of satellites due
to the coordinated and the pendant Se donor atoms.
However, in the case of compound 4, the appearance of
one set of satellites showed the exchange of coordinated
Se atom with the pendant Se atom and vice versa (eq
2). From this observation, it is inferred that the Sn-Se
Ge(1)-Se(1)-P(1)
105.24(5)
Se(1)-P(1)-Se(2)
109.63(8)
4
Sn(1)-C(13)
Sn(1)-C(1)
Sn(1)-C(7)
2.127(5) Sn(1)-Se(1)
2.133(5) Se(1)-P(1)
2.135(5) Se(2)-P(1)
2.5705(8)
2.1940(16)
2.0764(16)
C(13)-Sn(1)-C(7) 112.18(19) C(13)-Sn(1)-Se(1) 109.28(14)
C(1)-Sn(1)-C(7) 110.57(18) C(1)-Sn(1)-Se(1) 113.99(13)
C(13)-Sn(1)-C(1) 110.40(19) C(7)-Sn(1)-Se(1) 100.09(13)
Sn(1)-Se(1)-P(1)
101.52(4)
Se(1)-P(1)-Se(2)
112.68(7)
6
Sn(1)-C(13)
Sn(1)-C(7)
Sn(1)-C(1)
C(13)-Sn(1)-C(7) 110.0(2)
C(1)-Sn(1)-Se(1)
C(13)-Sn(1)-C(1) 110.5(2)
Sn(1)-Se(1)-P(1)
2.126(6) Sn(1)-Se(1)
2.130(6) Se(1)-P(1)
2.134(6) Se(2)-P(1)
2.5734(8)
2.1855(19)
2.0759(18)
C(7)-Sn(1)-Se(1) 100.38(15)
109.53(15) C(7)-Sn(1)-C(1)
111.9(2)
C(13)-Sn(1)-Se(1) 114.20(14)
Se(1)-P(1)-Se(2)
101.05(5)
112.82(8)
7
Pb(1)-C(5)
Pb(1)-C(11)
Pb(1)-C(17)
2.181(10) Pb(1)-Se(1)
2.185(9) Se(1)-P(1)
2.206(9) Se(2)-P(1)
2.6577(12)
2.199(3)
2.071(3)
C(5)-Pb(1)-C(11) 108.5(3)
C(5)-Pb(1)-C(17) 113.6(4)
C(11)-Pb(1)-C(17) 114.9(3)
C(5)-Pb(1)-Se(1) 111.6(3)
C(11)-Pb(1)-Se(1) 98.7(2)
C(17)-Pb(1)-Se(1) 108.5(3)
Pb(1)-Se(1)-P(1)
101.77(8)
Se(1)-P(1)-Se(2)
111.05(13)
compound 1, the Ge atom is bonded to three carbon
atoms of three phenyl groups with approximately equal
Ge-C bond distances (1.933, 1.943, and 1.947 Å), and
to one Se atom of [(EtO)2PSe2]- with Ge-Se(1) bond
distance of 2.405(1) Å. These Ge-C and Ge-Se bond
distances are close to the sum of the covalent radii of
Ge, C (1.99 Å), and Ge, Se (2.44 Å), respectively.46 The
coordinated P-Se(1) bond is longer, as expected, than
the pendant P-Se(2) bond (cf. P-Se, single bond, 2.32
Å)47 (Table 1). Three C-Ge-C and two C-Ge-Se bond
angles {other than C(1)-Ge(1)-Se(1) of 99.31°} lie in
the range 109-112°; the geometry around Ge center can
be treated as distorted tetrahedral. The structures of
4, 6, and 7 are identical to that of 1 and are listed in
Supporting Information (S1-S3). The structures of all
four compounds are analogous to those of dithiophos-
phates, [Ph3M{η1-S(S)P(OR)2}] (M ) Ge,42 Sn,43 Pb40).
NMR Spectroscopies. The NMR data (1H, 31P, 77Se)
of all of the complexes are listed in the Experimental
bonds are labile at ambient temperature and the NMR
spectrometer has recorded the average effect of the two
types of Se atoms on coupling with 31P nucleus. When
the 31P NMR spectrum of 4 was recorded at -90 °C in
CD2Cl2, there appeared again two sets of satellites due
to the coordinated and pendant Se donor atoms (1JP-Se
,
530, 859 Hz), along with a pair of satellites due to 31P-
119Sn coupling (2JP-Sn, 57.1 Hz).
The room temperature and variable temperature (VT)
NMR spectral characteristics of compounds 5-9 are
similar to those of 4; however, in the case of Pb, the 31
P
signals appear at somewhat lower field as compared to
either Ge or Sn compounds. Furthermore, it may be
1
noted that the JP-Se values of lead compounds are
higher for the coordinated PSe group (7, 558 Hz; 8, 557
Hz; 9, 557 Hz), and the pendant Se donor atoms have
1
Section. The H NMR spectral data showed peaks due
to CH3, CH2, OCH2, and CH protons of the alkoxyl
groups and ring protons of the phenyl groups, usually
as multiplets in their characteristic regions. Ph3M-ring
protons showed two sets of signals, a low field due to
o-protons and a high field due to m- and p-protons.
These phenyl protons are not sensitive to various OR
groups or to the nature of metals; however, Pb(IV) was
found to show these ring protons at somewhat low field,
vis-a`-vis those of Ge(IV) or Sn(IV) compounds. The 31P
NMR spectrum of compound 1 showed one singlet at δ
70.3 ppm with two pairs of satellites due to 31P-77Se
coupling, and the occurrence of two pairs is due to the
1
smaller JP-Se values (7, 846 Hz; 8, 847 Hz; 9, 847 Hz)
than the corresponding values in Sn or Ge compounds
(see Experimental Section). This shows a drift in
electron density from the pendant P-Se group to the
coordinated P-Se group. The exchange energies for
compounds 4-9 are calculated from the coalescence
temperature48 and lie in the range of 38-46 kJ mol-1
(Table 2). A typical spectrum of VT 31P NMR study can
be found in Supporting Information.
To establish whether the exchange pathway shown
in the eq 2 is intramolecular or intermolecular, VT 31P
NMR of equimolar amounts of 4 and 8 in CDCl3 was
measured. That the formation of compounds 5 and 7
(46) Inorganic Chemistry: Principles of Structure and Reactivity, 4th
ed.; Huheey, J. E., Keiter, E. A., Keiter, R. L., Eds.; Harper Collins
College Publishers: New York, 1993.
(48) Harris, R. K. Nuclear Magnetic Resonance Spectroscopy, 2nd
ed.; John Wiley & Sons: New York, 1989.
(47) Bondi, A. J. Phys. Chem. 1964, 68, 441.

Diselenophosphates of Group 14 Organometals
Organometallics, Vol. 24, No. 16, 2005 4075
Table 2. Exchange Energy between Coordinated
Scheme 1
q
and Pendant Se Atoms (∆G )
compound
T, K
δv
∆Gq, KJmol-1
(C6H5)3Sn[η1-Se(Se)P(OEt)2], 4 243.15 164.64
(C6H5)3Sn[η1-Se(Se)P(OiPr)2], 5 208.15 180.25
(C6H5)3Sn[η1-Se(Se)P(OnPr)2], 6 243.15 168.18
(C6H5)3Pb[η1-Se(Se)P(OEt)2], 7 218.15 143.9
(C6H5)3Pb[η1-Se(Se)P(OiPr)2], 8 208.15 145.1
(C6H5)3Pb[η1-Se(Se)P(OnPr)2], 9 218.15 145
45.81
38.79
45.77
41.15
39.16
41.13
could not be observed in the NMR experiment men-
tioned above suggests that the exchange is intramo-
lecular and is probably occurring via a four-membered
MSe2P ring. This is in line with the fact that both
2J(31P-119Sn) and 2J(31P-207Pb) do not show much
difference with temperature changes and values only
marginally decrease. Such data are listed in the Ex-
perimental Section for both room temperature and low
temperature.
of compound 1 for which this value is 10%. The ions
with the loss of one phenyl ring (type VIII) are generally
strong and exhibit intensity in the range 40-70% for
compounds 1, 4, 5, 7, and 8, while other compounds
show intensity in the range 2-10%. Further, the ions
with the loss of one desp ligand (type VII) are normally
very strong in intensity (100%) with the exception of
compound 9, for which the intensity was only 5%.
Finally, the most significant feature of FAB mass is the
observation of the formation of the dinuclear cation
bridged by a dsep ligand (type IX), which has shown
intensity in the range 4-15% for compounds 1, 3-5, 7,
and 8. Compounds 2 and 9 showed only a very weak
ion 0.2-1%, and for 6 no peak corresponding to IX was
detected. It is worthwhile to mention that the most
intense peak for lead compound 9 is detected at m/z )
514.0, which corresponds to the molecular ion with the
loss of all three phenyl groups.
It may be noted that none of compounds (4-9)
displayed 77Se NMR spectra at room temperature, and
these results suggest that coalescence has occurred at
room temperature. To verify this, a 77Se NMR of a
representative compound 4 has been recorded at 40 °C
in CDCl3, and it displayed a doublet at δ(Se) ) 64.2 ppm
1
with JP-Se ) 684.6 Hz, corresponding to the average
of two exchanging Se donor atoms. When the spectra
were recorded at low temperature, each of the com-
pounds showed two doublets: one due to the coordinated
Se donor atom and a second due to the pendant Se atom
like that in germanium.
A look at the δSe values for the coordinated Se donor
atoms for all compounds shows that for each R group,
the following trend operates regarding the appearance
of signal at low field: Ge > Pb > Sn. This implies that
the fluxionality may be due to both the electronic and
steric factors. In Sn and Pb compounds, a five-coordi-
nated transition state is easily accessible, whereas in
Ge, as a result of smaller atomic size, there is expected
more steric repulsion, which appears to prohibit flux-
ionality. In the related dithiophosphate complexes, such
as R3Sn{S(S)P(OEt)2}, the change in line width of 119Sn
NMR with temperature was used to study the exchange
of coordinated and pendant S donor atoms.49 Unfortu-
nately, the exchange energy was not available for the
comparison between the sulfur and selenium donor
atoms.
FAB-Mass Spectrometry. Positive FAB-mass spec-
tra of all the compounds were obtained, and major ions
along with their calculated values are listed in the
Experimental Section. The matching of calculated iso-
topic patterns and experimental values confirms the
assignment of ions listed. Besides the molecular ion
peak, (Ph3ML)+ (VI), two major peaks that correspond
to the intact molecule with the loss of one dsep ligand,
(Ph3M)+ (VII), and one phenyl ring, (Ph2ML)+ (VIII),
respectively, are also detected. Furthermore an ad-
ditional peak that can be formulated as [(Ph3M)2{Se2P-
(OR)2}]+ (IX), two triphenylmetal fragments bridged by
a dsep ligand, is revealed. A typical fragmentation
pattern is listed in Scheme 1. The molecular ion peaks
(type VI) are generally weak in intensity, and their
intensity varies in the range 1-5%, with the exception
A significant observation is that although compounds
1 and 3 formed nearly equal abundance of molecular
ion and dinuclear cation, the same is not true of
compounds 4, 5, 7, and 8, whose dinuclear cations are
several times intense over their molecular ions.
Structural Calculations for IX. The FAB-mass
spectra showed the formation of the dinuclear cations
IX (Scheme 1). Density functional theory calculations
are carried out in order to determine the likely struc-
tures of these dinuclear cations. The structures pre-
dicted for the model dinuclear cations, [(Ph3M)2Se2P-
(OMe)2]+ (M ) Ge, Sn, Pb), are shown in Figure 2. All
three model complexes are isostructural, and the ge-
ometry around each of P and M centers are ap-
proximately tetrahedral. For comparison, the structures
of [Ph3M{η1-Se(Se)P(OMe)2}] (M ) Ge, Sn, Pb) were also
optimized, as shown in Figure 3. The optimized struc-
tures are in agreement with the experimental structures
of [Ph3M{η1-Se(Se)P(OEt)2}] (M ) Ge (1), Sn (4), Pb-
(7)), revealing that the theory used in these calculations
is reliable. From the model structures as shown in both
Figures 2 and 3, it can be seen that the average P-Se
bond distance for a given M is slightly lengthened from
[Ph3M{η1-Se(Se)P(OMe)2}] to [(Ph3M)2Se2P(OMe)2]+.
The same trend is also observed for the M-Se bonds.
Coordination of an additional [Ph3M]+ to the dsep ligand
causes expansion of the coordination sphere around the
P atom.
In Scheme 1, it was proposed that the dinuclear
cations were formed from reaction of [Ph3M]+ and
[Ph3M{η1-Se(Se)P(OR)2}]. To study the feasibility of this
(49) Dakternieks, D.; Zhu, H.; Masi, D.; Mealli, C. Inorg. Chem.
1992, 31, 3606.

4076 Organometallics, Vol. 24, No. 16, 2005
Liu et al.
(Ge, Sn, and Pb). The exchange of coordinated and
pendant Se atoms for triphenyltin and triphenyllead
was explored by the VT 31P NMR, of which the line
shapes of satellite pairs provide important data for the
calculation of exchange energy, which was not available
in their corresponding sulfur analogues. Furthermore,
an interesting dinuclear cation, [(Ph3M)2Se2P(OMe)2]+,
identified in the positive FAB mass spectrum, was
studied by the density functional theory calculation for
its structure and the possible formation pathway. DFT
calculations for the molecular complexes were also
carried out.
Experimental Section
Materials and Instruments. All chemicals and reagents
were purchased from commercial sources and used as received.
Commercial ROH were distilled from Mg. Hexane and diethyl
ether were distilled from Na/K. All reactions were performed
in oven-dried Schlenk glassware by using standard inert-
atmosphere techniques. The starting materials, Ph3MCl (M
) Ge, Sn, Pb), were purchased from Aldrich Chemical Co. The
ligand, NH4Se2P(OR)2 (R ) Et, iPr, nPr), were prepared
according to literature methods.14 The elemental analyses were
Figure 2. Calculated structures for [(Ph3M)2Se2P(OMe)2]+
(M ) Ge, Sn, Pb). The bond distances are given in
angstroms and the bond angles are given in degrees.
1
done using a Perkin-Elmer 2400 CHN analyzer. H and 31P
NMR spectra were recorded on an Advance-300 Fourier
transform spectrometers. 77Se NMR spectra at 20 °C were done
on a Bruker AC-F200 and at -60 °C were done on Bruker
DMX-500 MHz. The 31P{1H} and 77Se{1H} NMR spectra are
referenced externally against 85% H3PO4 (δ ) 0) and Ph-
SeSePh (δ ) 463), respectively. Positive FAB mass spectra
were carried out on a VG 70-250S mass spectrometer with
nitrobenzyl alcohol as the matrix.
X-ray Crystallography. The diffraction data for all com-
plexes was collected at 293 K on a Bruker P4 diffractometer,
which was equipped with graphite-monochromated Mo KR (λ
) 0.71073 Å) radiation. All crystals were mounted on the top
of a glass fiber with epoxy cement. The data were collected
using 2θ-ω scan technique. Data reduction was performed with
SAINT,50 which corrects for Lorentz and polarization effects.
An empirical absorption correction (Ψ scans) was applied. All
structures were solved by the use of direct methods, and the
refinement was performed by the least-squares methods on
F2 with the SHELXL-97 package,51 incorporated in SHELXTL/
PC V5.10.52 Selected crystal data for the compounds are
summarized in the Experimental Section.
Figure 3. Calculated structural parameters for [Ph3M-
(η1-Se(Se)P(OMe)2] together with those observed (in pa-
rentheses) experimentally for 1, 4 and 7. The bond dis-
tances are given in angstroms and the bond angles are
given in degrees.
Computational Details. Density functional theory calcu-
lations at the B3LYP level53 were used to optimize all the
model complexes. The effective core potentials of Hay and
Wadt with double-ú valance basis sets (LanL2DZ)54 were
chosen to describe P, Se, Ge, Sn, and Pb. The 6-31G basis set
was used for C, H, and O atoms.55 Polarization functions were
also added for P (úd ) 0.340), Se (úd ) 0.338), Ge (úd ) 0.246),
Sn(úd ) 0.183), and Pb(úd ) 0.164).56 All calculations were
performed with the Gaussian 03 software package.57
proposal, the energies (∆E) for the reactions shown in
the eq 3 were estimated.
[Ph3M]+ + [Ph3M{η1-Se(Se)P(OMe)2}] f
[(Ph3M)2Se2P(OMe)2]+ (3)
[(C6H5)3Ge{(η1-Se(Se)P(OEt)2)}], 1. Diethyl ether (50 mL)
was added to a 1: l mixture of (C6H5)3GeCl (0.55 g, 1.609 mmol)
We obtained ∆E(Ge) ) -37.01 kcal/mol, ∆E(Sn) )
-39.03 kcal/mol, and ∆E(Pb) ) -36.13 kcal/mol. These
results suggest that affinity of [Ph3M]+ for [Ph3M{η1-
Se(Se)P(OR)2}] is strong, supporting the proposal given
in Scheme 1. The results also reveal that [Ph3Sn]+ has
the strongest affinity for the dsep ligand and [Ph3Pb]+
the weakest. On the basis of these reaction energies, it
is noted that the dinuclear cations are stable and may
be isolated if suitable counteranions are used.
(50) SAINT V4.043: Software for the CCD Detector System; Bruker
Analytical X-ray System: Madison, WI, 1995.
(51) Sheldrick, G. M. SHELXL-97: Program for the Refinement of
Crystal Structure; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
(52) SHELXL 5.10 (PC Verson): Program Library for Structure
Solution and Molecular Graphics; Bruker Analytical X-ray System:
Madison, WI, 1998.
(53) (a) Becke, A. D. J. Chem. Phys. 1993, 98, 5648. (b) Miehlich,
B.; Savin, A.; Stoll, H.; Preuss, H. Chem. Phys. Lett. 1989, 157, 200.
(c) Lee, C.; Yang, W.; Parr, G. Phys. Rev. 1988, B37, 785.
(54) (a) Hay, P. J.; Wadt W. R. J. Chem. Phys. 1985, 82, 270. (b)
Wadt, W. R.; Hay, P. J. J. Chem. Phys. 1985, 82, 284. (c) Hay, P. J.;
Wadt, W. R. J. Chem. Phys. 1985, 82, 299.
In conclusion, the first organometallic derivatives
containing dsep ligands in the monodentate connective
pattern (η1-Se) were revealed in the group 14 metals
(55) Hariharan, P. C.; Pople, J. A. Theor. Chim. Acta 1973, 28, 213.

Diselenophosphates of Group 14 Organometals
Organometallics, Vol. 24, No. 16, 2005 4077
and NH4Se2P(OEt)2 (0.46 g, 1.548 mmol). The mixture was
slowly stirred at 0 °C for 3 h, the solid NH4C1 formed during
reaction was filtered, and the filtrate was evaporated slowly
under vacuum. The residue obtained was then redissolved in
dichloromethane and layered with hexane, which afforded
crystalline material of 1. Yield: 0.82 g, 90%. Anal. Calcd for
C22H25O2PSe2Ge: C 45.33, H 4.32. Found: C 45.76, H 4.57.
1H NMR (300 MHz, CDCl3, δ, ppm): 0.91 (6H, t, CH3), 3.74
(2H, q, CH2), 3.99 (2H, q, CH2); 7.42 (9H, m, m- and p-Ph);
7.65 (6H, m, o-Ph)). 31P{1H} NMR (121.49 MHz, CDCl3, δ, ppm,
J, Hz): 70.3 (1JP-Se, 527, 876). 77Se NMR (38.18 MHz, CDCl3,
δ, ppm, J, Hz): 11.4 (d, 1JP-Se, 873), 142.0 (d, 1JP-Se, 530). FAB-
Mass, m/z ) 305 (303.9) [Ph3Ge+, 100%], 506.9 (505.8)[Ph2-
GeL+, 40%], 583.9 (582.9) [Ph3GeL+, 10%], 886.9(886.8) [(Ph3-
Ge)2L+, 9%].
Crystal data for 1: C22H25GeO2PSe2, M ) 582.9, triclinic,
P(-)1, a ) 9.3288(10) Å, b ) 10.7266(8) Å, c ) 12.8123(10) Å,
R )103.002(6)°, â ) 99.340(7)°, γ ) 99.322(7)°, V )1206.09-
(18) Å3, Z ) 2, Dc ) 1.605 g cm-3, µ ) 4.368 mm-1, T ) 293(2)
K, no. of unique reflections 3111, Rint ) 0.0273, 2502 reflections
with [I > 2σ(I)], final indices R1 ) 0.0407, wR2 ) 0.1028.
Crystal data for 4: C22H25O2PSe2Sn, M ) 629.00, triclinic,
P(-)1, a ) 9.4980(18) Å, b ) 10.2047(16) Å, c ) 13.0089 (19)
Å, R ) 97.550 (12)°, â ) 91.667(16)°, γ ) 98.835(13)°, V )
1233.6(4) Å3, Z ) 2, Dc ) 1.693 g cm-3, µ ) 4.065 mm-1, T )
293(2) K, no. of unique reflections, 3174, Rint ) 0.0224, 2839
reflections with [I > 2σ(I)], final indices R1 ) 0.0325, wR2 )
0.0807.
[(C6H5)3Sn{η1-Se(Se)(OiPr)2}], 5. Yield: 1.33 g, 89%. Anal.
Calcd for C24H29O2PSe2Sn: C 43.87, H 4.45. Found: C 44.42,
H 4.51. 1H NMR (300 MHz, CDCl3, δ, ppm): 1.15 (12H, m,
CH3), 4.78 (2H, m, CH), 7.43 (9H, m, m- and p-Ph); 7.73 (6H,
m, o-Ph). 31P{1H} NMR (121.49 MHz, CD2Cl2, δ, ppm, J, Hz):
at rt, 63.9 (1JP-Se 686, 2JP-Sn 58.4); at -90 °C, 65.1(1JP-Se 485,
2
1
846; JP-Sn 52.0). 77Se NMR (95.38 MHz, CD2Cl2 δ, ppm, J,
1
1
Hz): At -60 °C, 23.6 (d, JP-Se 854, Se.), 132.8(d, JP-Se 390,
Se.). FAB-Mass, m/z ) 351(350) [Ph3Sn+, 100%]; 580.9(580.0)
[Ph2SnL+, 40%], 657.9(657.1) [Ph3SnL+, 1%], 1006.2(1007.1)
[(Ph3Sn)2L+, 6.5%]
[(C6H5)3Sn{η1-Se(Se)(OnPr)2}], 6. Yield: 0.77 g, 87%. Anal.
Calcd for C24H29O2PSe2Sn: C 43.87, H 4.45. Found: C 43.02,
H 4.36. 1H NMR (300 MHz, CDCl3, δ, ppm): 0.75 (6H, t, CH3),
1.38 (4H, m, CH2), 3.80 (4H, t, OCH2); 7.43 (9H, m, m- and
p-Ph), 7.68 (6H, m, o-Ph). 31P{1H} NMR (121.49 MHz, CD2-
Cl2, δ, ppm, J, Hz): at rt, 70.5 (JP-Se 693, 2JP-Sn 58.0); at -90
Compounds 2-9 were prepared by a similar method and
important data are listed for each compound.
[(C6H5)3Ge{η1-Se(Se)(OiPr)2}], 2. Yield: 0.87 g, 86%. Anal.
Calcd for C24H29O2PSe2Ge: C 47.18, H 4.78. Found: C 48.56,
H 4.87. 1H NMR (300 MHz, CDCl3, δ, ppm); 1.01 (6H, m, CH3),
1.07 (6H, m, CH3), 4.76 (2H, m, CH), 7.44 (9H, m, m- and p-Ph),
7.67 (6H, m, o-Ph). 31P{1H} NMR (121.49 MHz, CDCl3, δ, ppm,
J, Hz): 65.3 (1JP-Se, 522, 868). 77Se NMR (38.18 MHz, CDCl3
δ, ppm, J, Hz): 1.98 (d, 1JP-Se, 868), 186.3 (d, 1JP-Se, 522). FAB-
Mass, m/z ) 305(303.9) [Ph3Ge+, 100%], 534 (533.9) [Ph2GeL+,
2%], 611(610.9) [Ph3GeL+, 3%], 915 (914.9) [(Ph3Ge)2L+, 0.2%].
2
°C, 72.1 (JP-Se 526, 863; JP-Sn, 50.9). 77Se NMR (95.38 MHz,
CD2Cl2 δ, ppm, J, Hz): at -60 °C, 19.3 (d, JP-Se, 867), 62.9(d,
JP-Se, 515.). FAB-Mass, m/z ) 351(350) [Ph3Sn+, 100%]; 580.9
(580.0) [Ph2SnL+, 2%], 657.0(657.1) [Ph3SnL+, 2%].
Crystal data for 6: C24H29O2PSe2Sn, M ) 657.05, triclinic,
P(-)1, a ) 9.5653(15) Å, b ) 10.4242(15) Å, c ) 13.5634(16)
Å, R ) 96.147(9)°, â ) 90.109(12)°, γ ) 99.216(12)°, V ) 1327.0-
(3) Å3, Z ) 2, Dc ) 1.644 g cm-3, µ ) 3.783 mm-1, T ) 293(2)
K, no. of unique reflections, 3446, Rint ) 0.0242, 3082 reflec-
tions with [I > 2σ(I)], final indices R1 ) 0.0365, wR2 ) 0.0902.
[(C6H5)3Pb{(η1-Se(Se)P(OEt)2)}], 7. Yield: 0.79 g, 89%.
Anal. Calcd for C22H25O2PSe2Pb: C 36.83, H 3.51. Found: C
37.47, H 3.87. 1H NMR (300 MHz, CD2Cl2, δ, ppm): 0.98 (6H,
m, CH3), 3.89 (4H, m, CH2); 7.52 (9H, m, m- and p-Ph), 7.72
(6H, m, o-Ph). 31P{1H} NMR (121.49 MHz, CD2Cl2, δ, ppm, J,
Hz): at rt, 73.1 (1JP-Se 704, 2JP-Pb 55.5); at -90 °C, 74.3 (1JP-Se
558, 846; 2JP-Pb 50.2). 77Se NMR (95.38 MHz, CD2Cl2, δ, ppm,
J, Hz): at -60 °C, 7.5 (d, 1JP-Se 857), 99.1 (d, JP-Se 570.). FAB-
Mass, m/z ) 439.1 (438.5) [Ph3Pb+, 100%]; 641.0(640.4) [Ph2-
PbL+, 50%], 717.0 (717.5) [Ph3PbL+, 1%], 1157(1156) [(Ph3-
Pb)2L+, 15%].
[(C6H5)3Ge{η1-Se(Se)(OnPr)2}], 3. Yield: 0.80 g, 85%. Anal.
Calcd for C24H29O2PSe2Ge: C 47.18, H 4.78. Found: C 47.76,
H 5.07. 1H NMR (300 MHz, CDCl3, δ, ppm): 0.75 (6H, m, CH3),
1.37 (4H, m, CH2), 3.76 (4H, m, OCH2), 7.43 (9H, m, m- and
p-Ph), 7.68 (6H, m, o-Ph). 31P{1H} NMR (121.49 MHz, CDCl3,
δ, ppm, J, Hz): 71.3 (1JP-Se, 527, 876). 77Se NMR (38.18 MHz,
CDCl3 δ, ppm, J, Hz): 7.1 (d, 1JP-Se, 870), 142.6 (d,1 JP-Se, 531).
FAB-Mass, m/z ) 305.0 (303.9) [Ph3Ge+, 100%], 534.8(533.9)
[Ph2GeL+, 10%], 611.8 (611) [Ph3GeL+, 5%], 914.9(914.9) [(Ph3-
Ge)2L+, 4%].
[(C6H5)3Sn{(η1-Se(Se)P(OEt)2)}], 4. Yield: 0.92 g, 87%.
Anal. Calcd for C22H25O2PSe2Sn: C 42.01, H 4.01. Found: C
1
42.23, H 3.84. H NMR (300 MHz, CDCl3, δ, ppm); 0.98 (6H,
m, CH3), 3.91 (4H, m, CH2), 7.43 (9H, m, m- abd p-Ph), 7.67
(6H, m, o-Ph). 31P{1H} NMR (121.49 MHz, CD2Cl2, δ, ppm, J,
Hz): at rt, 70.1 (1JP-Se 695, 2JP-Sn 59.1); at -90 °C, 71.6 (1JP-Se
530, 859, 2JP-Sn 57.1); 77Se NMR (95.38 MHz, CD2Cl2 δ, ppm,
J, Hz): at -60 °C, 13.2 (d, 1JP-Se 864), 58.3 (d, JP-Se 541). FAB-
Mass, m/z ) 351 (350) [Ph3Sn+, 100%], 552.8(551.9) [Ph2SnL+,
70%], 628.9(629.0) [Ph3SnL+, 3%], 978.8(979.0) [(Ph3Sn)2L+,
10%].
Crystal data for 7: C22H25PbO2PSe2, M ) 717.50, triclinic,
P(-)1, a ) 9.4973(11) Å, b ) 10.7536(18) Å, c ) 13.0308(18)
Å, R ) 103.449(11)°, â ) 99.553(7)°, γ ) 99.378 (11)°, V )
1247.9(3) Å3, Z ) 2, Dc ) 1.910 g cm-3, µ ) 9.755 mm-1, T )
293(2) K, no. of unique reflections, 3225, Rint ) 0.0347, 2826
reflections with [I > 2σ(I)], final indices R1 ) 0.0429, wR2 )
0.1060.
(56) Huzinaga, S. Gaussian Basis Sets for Molecular Calculations;
Elsevier Science: Amsterdam, 1984.
[(C6H5)3Pb{η1-Se(Se)(OiPr)2}], 8. Yield: 0.82 g, 82%. Anal.
Calcd for C24H29O2PSe2Pb: C 38.66, H 3.92. Found: C 39.76,
H 4.07. 1H NMR (300 MHz, CDCl3, δ, ppm): 1.11 (12H, m,
CH3), 4.76 (2H, m, CH), 7.48 (9H, m, m- and p-Ph), 7.73 (6H,
m, o-Ph), 31P{1H} NMR (121.49 MHz, CD2Cl2, δ, ppm, J, Hz):
(57) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J. R.; Montgomery, J. A.; Vreven, Jr., T.;
Kudin, K. N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.; Tomasi, J.;
Barone, V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.; Petersson,
G. A.; Nakatsuji, H.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.;
Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai,
H.; Klene, M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Adamo,
C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin,
A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma,
K.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V. G.;
Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas, O.; Malick, D. K.;
Rabuck, A. D.; Raghavachari, K.; Foresman, J. B.; Ortiz, J. V.; Cui,
Q.; Baboul, A. G.; Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.;
Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R. L.; Fox, D. J.;
Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Challa-
combe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.; Wong, M. W.;
Gonzalez, C.; Pople, J. A. Gaussian 03, revision B05; Gaussian, Inc.:
Pittsburgh, PA, 2003.
2
at rt, 67.2 (JP-Se 695, JP-Pb 61.6); at -90 °C, 68.9 (JP-Se 557,
847; 2JP-Pb 52). 77Se NMR (95.38 MHz, CD2Cl2 δ, ppm, J, Hz):
at -60 °C, 7.4 (d, JP-Se 848), 163.7 (d, 1JP-Se 562). FAB-Mass,
m/z ) 439.1(438.5) [Ph3Pb+, 100%]; 669.0(668.5) [Ph2PbL+,
40%], 745.0(745.6) [Ph3PbL+, 2%], 1185.1 (1184.1) [(Ph3Pb)2L+,
15%].
[(C6H5)3Pb{η1-Se(Se)P(OnPr)2}], 9. Yield: 1.09 g, 85%.
Anal. Calcd for C24H29O2PSe2Pb: C 38.66, H 3.92. Found: C
39.26, H 4.07. 1H NMR (300 MHz, CD2Cl2, δ, ppm): 0.73 (6H,

4078 Organometallics, Vol. 24, No. 16, 2005
Liu et al.
m, CH3), 1.42 (4H, m, CH2), 3.76 (4H, m, OCH2), 7.53 (9H, m,
m- and p- Ph), 7.72 (6H, m, o-Ph). 31P{1H} NMR (121.49 MHz,
CD2Cl2, δ, ppm, J, Hz): at rt, 73.3 (1JP-Se 704, 2JP-Pb 58.4); at
Acknowledgment. We are grateful to the National
Science Council of Taiwan (NSC 93-2113-M033-002) for
financial support.
2
-90 °C, 74.9(1JP-Se 557, 847; JP-Pb 52.2). 77Se NMR(95.38
Supporting Information Available: X-ray crystallo-
graphic files in CIF format for compounds 1, 4, 6, and 7 and
structures of 4, 6, and 7. This material is available free of
charge via the Internet at http://pubs.acs.org.
MHz, CD2Cl2, δ, ppm, J, Hz): at -60 °C, 11.4 (d, JP-Se, 868),
103.9 (d, 1JP-Se, 551). FAB-Mass, m/z ) 439.1(438.5) [Ph3Pb+,
5%]; 514.0(514.2) [(M - 3Ph)+, 100%], 669.0(668.5) [Ph2PbL+,
4%], 743.8(745.6) [Ph3PbL+, 0.3%], 1185.1(1184.1) [(Ph3Pb)2L+,
1%].
OM050291Q