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H. Kawasaki et al. / Inorganic Chemistry Communications 8 (2005) 777–781
CH2Cl2 Æ H2O (5), which were obtained by the reaction
of the corresponding aqua complexes, [Mo3O4ꢀnSn
(H2O)9]4+ (n = 0–4) [2] with Hqn in 0.5 M Hpts or
0.5 M HCl. Elemental analyses of these complexes
agreed with these formulae: 10, 1, 2, 3, 4, 5.2
Not only antibacterial and antifungal properties [3] of
Hqn and its derivatives, but also the first report by Tang
et al. [4] in 1987 on the electroluminescence of a bilayer
device using [Al(qn)3] as electron transfer and luminance
material has stimulated studies of a variety of complexes
with the ligands [5]. This new synthetic method of sol-
vent extraction using Hqn and its derivatives may give
another route for the synthesis of complexes with the
ligands. Although a number of mononuclear [6] or binu-
clear [7] molybdenum complexes containing the ligands
have been reported, no report on tri- or more nuclear
sulfur-bridged molybdenum clusters with the ligands
has appeared except that the presence of [Mo3S7(qn)3]+
was suggested by FAB-MASS [8]. In addition, the syn-
thesis of the complexes enabled us to find anomalous
chemical shifts.
Fig. 1. The ORTEP drawing of the [Mo3S4(Clqn)3(H2O)3]+ (10).
˚
Selected bond lengths (A) and bond angles (ꢁ): Mo1–Mo2, 2.7403(5);
Mo1–Mo3, 2.7869(7); Mo2–Mo3, 2.7720(5); Mo1–S1, 2.341(1); Mo2–
S1, 2.353(1); Mo3–S1, 2.341(1); Mo1–S2, 2.287(1); Mo1–S4, 2.315(1);
Mo2–S2, 2.298(1); Mo2–S3, 2.303(1); Mo3–S3, 2.280(1); Mo3–S4,
2.3234(9); Mo1–O11, 2.062(3); Mo2–O21, 2.083(3); Mo3–O31,
2.066(3); Mo1–N1, 2.225(3); Mo2–N2, 2.233(4); Mo3–N3, 2.228(3);
Mo1–O12, 2.258(3); Mo2–O22, 2.207(3); Mo3–O32, 2.196(3) and
Mo2–Mo1–Mo3, 60.20(1); Mo1–Mo2–Mo3, 60.74(2); Mo1–Mo3–
Mo2, 59.07(1).
The structure of 10 was determined by X-ray crystal-
lography, and an ORTEP drawing of the cation of 10 is
shown in Fig. 1 together with the relevant bond dis-
tances. The cation of 10 has neither crystallographic
nor non-crystallographic symmetry elements. The nitro-
gen atom of each ligand coordinates to molybdenum
atom so that the atom locates trans to l3-S.
solvent DMSO molecules probably replace the coordi-
nated water molecules of the clusters.
The assignments of the proton signals of 10, 1, 4, and
5 are rather straightforward and they are noted in Fig. 2.
Their chemical shifts depend very much on the kinds of
the bridging atoms, i.e., sulfur or oxygen. Among them,
Ha signal in each spectrum is distinctly separated from
other signals and the chemical shift dependence on the
bridging atoms is very large. Therefore, we will mainly
discuss the chemical shift dependence of Ha protons
on the bridging atoms.
1H NMR spectra of the six kinds of clusters (10, 1, 2, 3,
4, 5) and two kinds of ligands (HClqn and Hqn) in
DMSO-d6 are shown in Fig. 2 together with their assign-
ments [9]. The HH correlation spectra of 10 and 1 support
their assignments. Although there are three kinds of
1
Clqnꢀ ligands in 10, the H NMR spectrum shows only
one kind of signals. This phenomenon indicates that 10
has a structure with a threefold rotation axis in DMSO
solution as shown in the inset (together with names of
protons) of Fig. 2, though the X-ray structure analysis
shows that 10 does not have the symmetry element. The
1H NMR spectra of 10 and 1 are very similar to each
other except that He signal of 10 appears as a doublet
due to a coupling only to Hf, while He signal of 1 appears
as doublet of doublets due to a coupling to Hd and Hf.
Therefore, 1 also has a structure with a threefold rotation
axis in DMSO solution as shown in the inset of Fig. 2.
Each of the spectra of 4 and 5 also shows only one kind
of qnꢀ signal, which indicates that these clusters also
have structures with threefold rotation axes in DMSO
solution as shown in the inset of Fig. 2. In the solution,
Ha signals of 10 (10.29 ppm (3H, d))3 and 1 (10.17 ppm
(3H, d)) appear at very low magnetic fields compared to
those of the free ligands, HClqn (8.95 ppm (1H, d)) and
Hqn (8.85 ppm (1H, d)). A large upfiled chemical shift of
Ha was observed when three l2-Ss of 1 were replaced by
three l2-Os to give 4. The direction of the chemical-shift-
change is opposite to the direction deduced from the
electronegativity change from sulfur to oxygen [10].
There is a report on the XPS spectra of the incomplete
cubane type sulfur/oxygen-bridge clusters [Mo3O4ꢀnSn
(NCS)9]5ꢀ (n = 0–3) and [Mo3S4(NCS)8(H2O)]4ꢀ, where
4þ
the number of sulfurs in the Mo3O
S
core increased,
4ꢀn
n
and the binding energies of Mo-3d5/2 and Mo-3d3/2
decreased. That the bridging sulfur attracts fewer elec-
trons from the molybdenum atoms than the bridging
oxygen explains the XPS spectra [11]. The explanation
2
All of the electronic spectra of the clusters in dichloromethane have
strong peaks in the near ultraviolet region. The peak positions are: 10,
428 nm; 1, 415 nm; 2, 410 nm; 3, 403 nm; 4, 397 nm; and 5, 384 nm. In
strictly dehydrated dichloromethane, the peaks of the electronic
spectra of 10 and 1 show relatively large splits, and that of 2 shows a
shoulder. Remaining clusters show no split.
3
In addition to the splitting (the coupling constant 3JHH = 4.96 Hz),
a further splitting with a smaller coupling constant (4JHH = ca. 1 Hz)
was observed, but was not described here. Almost all the signals in
Fig. 2 showed this kind of further splitting.
Kawasaki, Hideki
