Synthesis, spectroscopic and X-ray structural studies of mercury(II) halide complexes of 4-methoxybenzoylmethylenetriphenylphosphorane

Article abstract of DOI:10.1016/j.poly.2007.01.053

The reactions of the title ylide {(C₆H₅)₃PCHCOC₆H₄ OCH₃)} (MBPPY) with mercury(II) chloride and mercury(II) bromide in equimolar ratios using methanol as the solvent produces crystals of [(MBPPY) · HgCl₂]₂ (1) and [(MBPPY) · HgBr₂]₂ (2), respectively. Single crystal X-ray analyses reveal the presence of centrosymmetric dimeric structures containing the ylide and HgX₂ (X = Cl or Br) in both cases. The IR and NMR data of the product [(MBPPY) · HgI₂]₂ (3), formed by the reaction of mercury(II) iodide with the same ylide, are similar to those of 1 and 2. Analytical data indicate a 1:1 stoichiometry between the ylide and Hg(II) halide in each of the three products.

Full text of DOI:10.1016/j.poly.2007.01.053

Polyhedron 26 (2007) 2845–2850
www.elsevier.com/locate/poly
Synthesis, spectroscopic and X-ray structural studies of mercury(II)
halide complexes of 4-methoxybenzoylmethylenetriphenylphosphorane
a,
a
b
Seyyed Javad Sabounchei *, Vida Jodaian , Hamid Reza Khavasi
a
Faculty of Chemistry, Bu-Ali Sina University, Hamadan, Iran
Department of Chemistry, Shahid Beheshti University, Evin, Tehran, 19839-63113, Iran
b
Received 24 December 2006; accepted 23 January 2007
Available online 16 February 2007
Abstract
The reactions of the title ylide {(C6H5)3PCHCOC6H4OCH3)} (MBPPY) with mercury(II) chloride and mercury(II) bromide in equi-
molar ratios using methanol as the solvent produces crystals of [(MBPPY) Æ HgCl2]2 (1) and [(MBPPY) Æ HgBr2]2 (2), respectively. Single
crystal X-ray analyses reveal the presence of centrosymmetric dimeric structures containing the ylide and HgX2 (X = Cl or Br) in both
cases. The IR and NMR data of the product [(MBPPY) Æ HgI2]2 (3), formed by the reaction of mercury(II) iodide with the same ylide, are
similar to those of 1 and 2. Analytical data indicate a 1:1 stoichiometry between the ylide and Hg(II) halide in each of the three products.
ꢀ 2007 Elsevier Ltd. All rights reserved.
Keywords: Phosphorus ylide; Mercury(II) halide complexes; X-ray Crystal structure; Triphenylphosphine
1. Introduction
examples of O-coordinated ylides are known [9–13]. Some
of these examples contain the ylide O-coordinated to a
hard, very oxophilic metal center, as Sn(IV) [9,10] or group
4 metals with a high oxidation number [11]. Only W(0)
complexes of the type W(CO)5L (L = ylide) [12] and Pd(II)
complexes of the stoichiometry [Pd(C6F5)L2)(APPY)]
(ClO4) [13] [APPY = Ph3CCOMe; L = PPh3, PBu3;
L2 = bipy] contain stable ylides O-linked to a soft metal
center. Other attempts to obtain this kind of O-coordina-
tion to ‘‘classical’’ soft metals such as Pd(II), Pt(II) or
Hg(II) [6,14,15] invariably gave C-coordination. In this
study, we describe the preparation, spectroscopic charac-
terization (IR and NMR) of complexes of mercury(II) with
the title ylide. By a comparison of the data collected and
single crystal X-ray diffraction of 1 and 2, it demonstrates
C-coordination of the ylide to the metal.
The organometallic chemistry of phosphorous ylides
R3P = C (R0) (R00) (R, R0, R00 = alkyl or aryl groups) has
undergone a great growth in the last few years, mainly due
to their interesting application as reactants in organometallic
and metal-mediated organic synthesis [1–4]. On the whole,
the a-keto-stabilized phosphorous ylides R3P = C(R0)COR00
show interesting properties such as high stability (which
allows them to be easily handled in air) and ambidentate
character as ligands (C- versus O-coordination). This ambid-
entate character can be rationalized in terms of the resonance
forms A–C, together with the isomeric form D (Scheme 1).
Form B would account for C-coordination to a metal
(M = metal) (which is presented as G) while isomers C and
D would explain O-coordination (which are presented as
cisoid, form F, and transoid, form E, respectively).
In the compounds reported to date, the chemical behav-
ior of the a-keto phosphorous ylides has been clearly dom-
inated by the C-coordinated form [5–8], and very few
2. Experimental
2.1. Materials
*
Mercury halides, 4-methoxyacetophenone and triphe-
nylphosphine were purchased from Merck. The ligand
Corresponding author. Fax: +98 811 8257407.
E-mail address: jsabounchei@yahoo.co.uk (S.J. Sabounchei).
0277-5387/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2007.01.053

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S.J. Sabounchei et al. / Polyhedron 26 (2007) 2845–2850
Scheme 1.
was synthesised by the reaction of triphenylphosphine with
a chloroform solution of 2-bromo-40-methoxyacetophe-
none and dehydrogenated by NaOH [16]. All solvents were
dried by the reported methods [17].
direct methods and refined by full-matrix least-squares on
F2 by SHELX [19] and using the X-STEP3211 crystallographic
software package [20]. All non-hydrogen atoms were
refined anisotropically using reflections I > 2r(I). Hydro-
gen atoms were inserted at calculated positions using a rid-
ing mode with fixed thermal parameters. Data collection
and refinement parameters are given in Table 1. ORTEP
views of the X-ray crystal structures of the two complexes
2.2. Physical measurements
Melting points were measured on a SMPI apparatus.
Elemental analysis for C, H and N were performed using
a Perkin–Elmer 2400 series analyzer. Fourier transform
IR spectra were recorded on a Shimadzu 435-U-04 spectro-
photometer and samples were prepared as KBr pellets. 1H,
13C and 31P spectra were recorded on a 200 MHz Bruker
spectrometer in DMSO-d6 or CDCl3 solution at 25 ꢁC.
The single crystal X-ray diffraction analysis was per-
formed on a STOE IPDS-II two circle diffractometer at
298 K, using graphite monochromated Mo Ka radiation
(k = 0.7107 nm). A suitable crystal, grown from a metha-
nol-diethylether solution, was mounted on a glass fiber.
The data collection was performed at room temperature
using the x-scan technique and using the STOE X-AREA
software package [18]. The crystal structure was solved by
˚
are shown in Figs. 1 and 2. Selected bond lengths (A) and
bond angles (ꢁ) for complexes 1 and 2 are given in Table 2.
2.3. Synthesis of MBPPY
To a chloroform solution (25 ml) of triphenylphosphine
(0.131 g, 0.5 mmol) was added 2-bromo-40-methoxyace-
tophenone (0.114 g, 0.5 mmol) and the resulting mixture
was stirred for 12 h. The solution was filtered off, the pre-
cipitate washed with diethelyether and dried. Further treat-
ment with aqueous NaOH solution (0.5 M) led to
elimination of HBr, giving the free ligand MBPPY. M.p:
153–158 ꢁC. Anal. Calc. for C27H23O2P: C, 67.24; H,
4.84. Found: C, 66.05; H, 4.88%.

S.J. Sabounchei et al. / Polyhedron 26 (2007) 2845–2850
2847
Table 1
C42
C43
O3
Crystal data and refinement details for [MBPPY Æ HgCl2]2 (1) and
[MBPPY Æ HgBr2]2 Æ 2(C2H5)2O (2)
C41
C44
Compound
1
2
C33
Empirical formula
Formula weight
Crystal system
Space group
C54H46Cl4Hg2O4P2
363.83
triclinic
C62H66Br4Hg2O6P2
1689.87
triclinic
C34
C32
C12
C13
C14
C23
C24
C25
C35
C36
C15
C22
C21
ꢀ
ꢀ
C31
P1
P1
C11
Crystal size (mm)
0.2 · 0.13 · 0.08
10.3360(12)
13.7444(16)
19.657(2)
101.406(9)
91.117(9)
108.725(9)
2582.2(5)
293(2)
0.2 · 0.15 · 0.05
11.181(6)
13.095(8)
13.124(8)
115.88(4)
110.37(5)
91.13(5)
186.8(16)
293(2)
C16
P1
C9
˚
a (A)
Br2
˚
C26
O2
b (A)
Hg1
Br1
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
C8
C5
3
˚
C6
C4
C3
V (A )
Temperature (K)
C7
Z
2
1
Calculated density (Mg/m3)
1.754
1.768
C2
F (000)
Reflections collected
1320
23521
816
16157
O1
hmax (ꢁ)
1.6–26.80
1.77–28.22
C1
Final R indices [I > 2r(I)]
R1
wR2
0.0335
0.0559
0.0832
0.1915
Fig. 2. ORTEP view of the X-ray crystal structure of [MBPPY Æ
HgBr2]2 Æ 2(C2H5)2O.
R indices (all data)
R1
0.0460
0.0593
1.134
0.1105
0.2092
1.235
wR2
Goodness-of-fit on F2
P
P
R1 = iFoj ꢀ jFci/ jFoj for reflections with I > 2rI.
P
P
2
2 1=2
wR2 ¼ ½ wðjF 2o j ꢀ jF c2 j Þ = jF 2oj ꢁ
.
Table 2
˚
Selected bond lengths (A) and angles (ꢁ) for the structures of 1 and 2
1
2
Bond distances
Hg (1)–C(9)
Hg(1)–Cl(1)
Hg(1)–Cl(2)
Hg(1)–Cl(2)#1
C(8)–O(2)
2.215(4)
2.418(14)
2.504(11)
2.884(12)
1.219(5)
1.498(5)
1.789(4)
1.806(4)
1.801(4)
1.486(6)
1.785(4)
2.218(11)
2.559(2)
2.603(3)
3.022(2)
1.251(13)
1.470(16)
1.796(13)
1.806(11)
1.800(12)
1.528(14)
1.827(11)
C(8)–C(9)
C(11)–P(1)
C(21)–P(1)
C(31)–P(1)
C(5)–C(8)
C(9)–P(1)
Bond angles
Hg(1)–Cl(2)–Hg(1)#1
C(9)–Hg(1)–Cl(1)
C(9)–Hg(1)–Cl(2)
Cl(1)–Hg(1)–Cl(2)
C(9)–Hg(1)–Cl(2)#1
Cl(1)–Hg(1)–Cl(2)
Cl(2)–Hg(1)–Cl(2)#1
C(8)–C(9)–Hg(1)
P(1)–C(9)–Hg(1)
C(8)–C(9)–P(1)
96.10(4)
90.16(7)
113.2(3)
132.9(3)
107.67(7)
99.8(3)
119.34(10)
129.16(10)
106.59(5)
98.17(11)
110.86(5)
83.90(4)
104.9(2)
113.00(19)
112.4(3)
106.36(7)
89.84(7)
104.8(7)
114.3(5)
111.2(7)
118.8(9)
119.9(10)
105.5(5)
113.8(6)
112.4(5)
107.7(6)
108.6(6)
108.6(6)
121.2(10)
Fig. 1. ORTEP view of the X-ray crystal structure of [MBPPY Æ HgCl2]2.
C(9)–C(8)–C(5)
119.5(3)
121.3(3)
2.4. Synthesis of the complexes
O(2)–C(8)–C(5)
C(11)–P(1)–C(9)
C(31)–P(1)–C(9)
C(21)–P(1)–C(9)
C(11)–P(1)–C(31)
C(11)–P(1)–C(21)
C(31)–P(1)–C(21)
O(2)–C(8)–C(9)
110.80(19)
107.86(1)
113.00(18)
107.62(19)
109.33(19)
108.05(18)
119.2(4)
2.4.1. [MBPPY Æ HgCl2]2 (1)
To a methanolic solution (5 ml) of MBPPY (0.102 g,
0.25 mmol) was added mercury(II) chloride (0.067 g,
0.25 mmol). The mixture was stirred for 4 h. The white solid
product was separated by filtration and washed with dietyl
ether. Yield: 92.0%, m.p. 256–259 ꢁC. Anal. Calc. for

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S.J. Sabounchei et al. / Polyhedron 26 (2007) 2845–2850
C54H46O4P2Hg2Cl4: C, 47.3; H, 3.6. Found: C, 48.80; H,
3.41%.
the m(P+–Cꢀ) values for all three complexes were shifted to
lower frequencies and were observed at 825, 820 and
812 cmꢀ1 for 1, 2 and 3, respectively, suggesting some
removal of electron density from the P–C bond.
2.4.2. [MBPPY Æ HgBr2]2 (2)
To a methanolic solution (5 ml) of MBPPY (0.102 g,
0.25 mmol) was added mercury(II) bromide (0.091 g,
0.25 mmol). The mixture was stirred for 4 h. The solvent
was then removed in vacuo. The white product obtained
was washed with ice-cold methanol and dried in vacuum.
Yield: 87.2%, m.p. 203–205 ꢁC. Anal. Calc. for C54H46-
O4P2Hg2Br4: C, 40.66; H, 3.11. Found: C, 40.73; H, 2.88%.
3.3. NMR spectral data
1
3.3.1. H NMR spectra
The chemical shifts corresponding to the protons of the
ligand and the complexes are listed in Table 3. The signals
due to methine protons, when recorded in CDCl3, were
either broad or unobserved probably due to the very low
solubility of all the complexes in CDCl3. Similar behaviour
was observed earlier in the case of ylide complexes of pla-
tinium(II) chloride [23]. However, a sharp doublet for the
above proton was obtained in DMSO-d6 for each of the
three complexes in the same region. This indicates that
the complexes do not react with DMSO-d6. The appear-
ance of a sharp doublet signal and expected downfield shift
for the CH proton show the coordination of carbon
through the methine group.
2.4.3. [MBPPY Æ HgI2]2 (3)
To a methanolic solution (5 ml) of MBPPY (0.102 g,
0.25 mmol) was added mercury(II) iodide (0.113 g,
0.25 mmol). The mixture was stirred for 12 h. On concen-
tration by removing the solvent by vacuum, a pale yellow
precipitate was obtained. The products were washed with
benzene and dried in vacuo. Yield: 81%, m.p. 242–
245 ꢁC. Anal. Calc. for C54H46O4P2Hg2I4: C, 37.49; H,
2.67. Found: C, 36.80; H, 2.64%.
3.3.2. 31P NMR spectra
3. Results and discussion
The proton decoupled 31P NMR spectra show only one
sharp singlet between d 22.65–24.58 ppm for the complexes
(Table 3). Chemical shift values for the complexes appear
to be downfield by about d 8–10 ppm with respect to the
parent ylide (d 14.061 ppm), indicating coordination of
the ylide has occurred. The appearance of single signals
for the PCH group in each of the 31P and 1H NMR spectra
indicates the presence of only one isomer for all the three
complexes, as expected for C-coordination. It must be
noted that O-coordination of the ylide generally leads to
the formation of cis and trans isomers, giving rise to two
3.1. Synthesis
The ligand was synthesised by treating 2-bromo-40-
methoxyacetophenone (prepared by reacting 4-methoxy-
acetophenone with bromide in glacial acetic acid) with
triphenylphosphine and removal of the proton from the
phosphonium salt. Reactions of HgX2 with the ylide in a
1:1 stoichiometry afforded the C-coordinated complexes
with a halo-bridged dimeric structure:
1
different signals in 31P and H NMR spectra [24].
3.3.3. 13CNMR
The 13CNMR data of the complexes and the title ylide
are listed in Table 3, along with possible assignments. The
most interesting aspect of the 13CNMR spectra of the
complexes is the upfield shift of the signals due to the yli-
dic carbon. Such an upfield shift observed in PdCl(g3–2-
XC3H4) (C6H5)3PCHCOR (X = H, CH3; R = CH3,
C6H5) was attributed to the change in hybridization of
the ylidic carbon [25]. Similar upfield shifts of 2–3 ppm
with reference to the parent ylide were also observed in
the case of [(C6H5)3PC5H4HgI2]2 [23]. The 13C shifts of
the CO group in the complexes are around 189 ppm, rel-
ative to 184.265 ppm noted for the same carbon in the
parent ylide, indicating much lower shielding of the car-
bon of the CO group in these complexes. No coupling
3.2. Infra-red spectra
The m(CO) band, which is sensitive to complexation,
occurs at 1601 cmꢀ1 in the parent ylide, as in the case of other
resonance stabilized ylides [21]. Coordination of the ylide
through C-coordination causes an increase in m(CO) while
for O-coordination a lowering of m(CO) is expected. The
IR absorption bands observed for the three complexes at
1630, 1626 and 1620 cmꢀ1 indicate coordination of the ylide
thorough carbon. The m(P+–Cꢀ) which is also diagnostic of
the coordination occurs at 837 cmꢀ1 in (C6H5)3P+–C–H2
and at 878 cmꢀ1 in (C6H5)3PCHCOC6H5 [22]. These assign-
ments were confirmed by comparing the IR spectra of the
corresponding 13C substituted ylides. In the present study,
1
to Hg was observed at room temperature in the H, 13C
and 31P NMR spectra for all these complexes. Failure
to observe satellites in the above spectra was previously
noted in the ylide complexes of Hg(II) [26] and Ag(I)
[27], which had been explained by fast exchange of the
ylide with the metal.

S.J. Sabounchei et al. / Polyhedron 26 (2007) 2845–2850
2849
Table 3
1H, 13C and 31P NMR data of MBPPY and its complexes with mercury (II) halides
Compound
MBPPY
1H chemical shifts (d ppm)
13C chemical shifts (d ppm)
31P chemical shifts (d ppm)
3.79 (3H, OCH3)
55.08 (s, OCH3)
14.06 (s)
4.25 (1H, d (J = 15.68 Hz), CH)
6.80–8.21 (19H, m, C6H5)
49.21 (d, (J = 119.24 Hz), CH)
126.77 (d, (J = 74.8 Hz), PPh3(i))
128.70 (d, (J = 12.4 Hz), PPh3(m))
131.89 (s, PPh3(p))
133.98 (d, (J = 10.2 Hz), PPh3(o))
160.65 (s, CO. Ph (i))
184.26 (s, CO)
MBPPY Æ HgCl2
MBPPY Æ HgBr2
MBPPY Æ HgI2
3.83 (3H, OCH3)
5.43 (1H, d, CH)
6.81–8.20 (19H, m, C6H5)
123.46 (d, (J = 88.58 Hz), PPh3(i))
129.32 (d, (J = 12.61 Hz), PPh3(m))
131.89 (s, PPh3 (p))
133.29 (d, (J = 8.22 Hz), PPh3(o))
162.58 (s, CO. Ph (i))
24.58 (s)
23.58 (s)
22.65 (s)
189.76 (s, CO)
3.81 (3H, OCH3)
5.45 (1H, d, CH)
6.90–8.30 (19H, m, C6H5)
123.51 (d, (J = 89.12 Hz), PPh3(i))
129.37 (d, (J = 12.7 Hz), PPh3 (m))
130.41 (s, PPh3(p))
133.34 (d, (J = 9.57 Hz), PPh3(o))
162.58 (s, CO. Ph (i))
190.56 (s, CO)
3.82 (3H, OCH3) 22.67 (s)
5.25 (1H, d (J = 6.98 Hz), CH)
6.85–8.20 (19H, m, C6H5)
123.76 (d, (J = 90.22 Hz), PPh3(i))
129.45 (d, (J = 12.79 Hz), PPh3(m))
130.21 (s, PPh3 (p))
133.31 (d, (J = 9.68 Hz), PPh3(o))
162.43 (s, CO. Ph (i))
188.71 (s, CO)
s = singlet, d = double, m = multiplet, o = ortho, m = meta, p = para, i = ipso.
3.4. Crystal structure
bon, but that steric hindrance around the metal centre or
the ylidic carbon will necessitate O-coordination. Indeed,
this trend is reflected here, both BPPY and MBPPY are
slightly less sterically demanding than ABPPY, and both
are C-coordinated to Hg(II).
The solid state structures of complexes 1 and 2 have
been established by single crystal X-ray analysis, which
revealed triclinic units. The molecular structures are shown
in Figs. 1 and 2, and selected interatomic parameters are
collected in Table 2.
The dimeric structure adopted by complexes 1, 2 and 3 is
in contrast to the O-coordinated trinuclear mercury(II)
complex of the phosphorus ylide Ph3PCHCOPh [28], but
is similar to the structure of trans-di-l-iododiiodobis(tri-
The Hg(II) centre forms four close contacts with sp3
hybridization and has a 4-coordinate environment with
one short Hg–X bond, one Hg–C bond and two asymmet-
ric bridging Hg–X bonds at distances of 2.504(11) and
˚
˚
2.884(12) A in 1 and 2.603(3) and 3.022(2) A in 2.
The significant shortening of the Hg–C bond length,
˚
˚
phenylphosphoniumcyclopentadienylide)
dimercury(II)
2.215(4) A 1 and 2.218(11) A 2 compared to analogous dis-
reported by Baenziger et al. [29] and the C-coordinated
dinuclear mercury(II) halide complexes of Ph3CHCOPh
(BPPY) [30]. The C-coordination of MBPPY is in stark
contrast to the O-coordination of the phosphorus ylide,
Ph3PC(COMe)(COPh) (ABPPY), to a Hg(II) centre [31].
The difference in coordination mode between ABPPY
and MBPPY to Hg(II) can be rationalized in terms of the
electronic properties and steric requirements of the ylides.
The nucleophilicity of the carbanion in ABPPY is less than
for MBPPY; this is due to the additional delocalization of
the ylide electron density in ABPPY which is facilitated by
the second carbonyl group. This will reduce the ability of
ABPPY to bind via the ylidic carbon. Belluco et al. have
studied steric influences on the coordination modes of ylide
molecules to Pt(II) systems [32]. These authors concluded
that the preferred coordination mode is via the ylidic car-
tances in [(C6H5)3PCHCOC6H5HgI2]2 [30] and in
[(C5H4P(C6H5)3HgI2]2 [33] (2.312(13) and 2.292(8) A,
˚
respectively) must be attributed to the use of mercury orbi-
tals with high s character for bonding to the ylidic carbon.
The use of non-equivalent hybrid orbitals with high s char-
acter to bond to low electronegative atoms was proposed
by Bent in the concept of isovalent hybridization to
account for the variation in bond lengths and bond angles
around a central atom [34].
˚
The terminal Hg–Cl bond length, 2.418(14) A 1 is com-
˚
parable to 2.400 A observed in the case of Hg2Cl5N2-
C11H12, which has a tetrahedral coordination environment
around mercury with a bridging structure [35]. The two
˚
bridged Hg–Cl bonds fall within the range 2.620–3.080 A
reported for other structures [36] containing chloro bridged
mercury.

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S.J. Sabounchei et al. / Polyhedron 26 (2007) 2845–2850
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The angles around mercury vary from 83.90(4)ꢁ to
Chem. Soc. 120 (1998) 4863.
129.16(10)ꢁ for the chloride and 89.84(7)ꢁ to 132.9(3)ꢁ for
the bromide, a very distorted tetrahedral environment.
This distortion must be due to the higher s character of
the sp3 hybrid mercury orbitals involved in the above
bonds and the formation of a strong halogen bridge
between the Hg atoms which requires the internal XHgX
angle to be considerably smaller.
[3] O.I. Kolodiazhnyi, Russ. Chem. Rev. 66 (1997) 225.
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The stabilized resonance structure for the title ylide
is destroyed by the complexes formation. Thus, the
C(8)–C(9) bond length (1.498(5) A, 1 and 1.470(16) A, 2)
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˚
˚
is significantly longer than the corresponding bond found
˚
in a similar uncomplexed phosphorane (1.407(8) A) [37].
On the other hand, the bond length of P(1)–C(9) in the
˚
similar ylide is 1.706 A [24] which shows that the above
˚
bond is considerably elongated to 1.785(4) A and
˚
1.827(11) A in complexes 1 and 2, respectively. The plane
defined by the two mercury atoms and the two bridging
halogens is perfectly planar in both structures. The inter-
nuclear distances between mercury atoms were found to
˚
˚
be 3.901(7) A and 3.994(8) A in structures 1 and 2, respec-
tively. These distances are much longer than the sum of
˚
Van der Waals radii (1.5 A) of the two mercury atoms
[38] indicating the absence of significant bonding interac-
tions between the mercury atoms in the molecular struc-
tures. The adaptation of dimeric structures in Hg(II)
ylide complexes may be explained by both the preference
of Hg(II) to four coordination and the stability of the 18
electron configuration around Hg(II).
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4. Conclusions
The present study describes the synthesis and character-
ization of a series of mercury ylide complexes. On the basis
of the physico-chemical and spectroscopic data we propose
that MBPPY herein exhibits monodentate C-coordination
to the metal center, which is further confirmed by the
X-ray crystal structures of the complexes.
5. Supplementary material
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B 34 (1978) 2300.
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Wen, J. Organomet. Chem. 491 (1995) 103.
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Krause Baure, Chem. Commun. (2001) 1660.
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Zanotto, M. Mozzon, M. Furlan, E. Zangrando, Inorg. Chim. Acta
(1996) 355.
CCDC 622081 and 620129 contains the supplementary
crystallographic data for this paper. These data can be
obtained free of charge via http://www.ccdc.ac.uk/conts/
retrieving.html, or from the Cambridge Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK;
fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.cam.
ac.uk.
[33] N.I. Holy, N.C. Baenziger, R.M. Flynn, D.C. Swenson, J. Am. Chem.
Soc. 98 (1976) 7823.
Acknowledgements
[34] H.A. Bent, Chem. Rev. 61 (1961) 75.
[35] A. Albinati, S.V. Meille, F. Cariati, G. Marcotrigiano, L. Menabue,
G.C. Pellacani, Inorg. Chim. Acta 38 (1984) 221.
[36] N.A. Bell, S.J. Coles, M.B. Hursthouse, M.E. Light, K.A. Malik, R.
Mansor, Polyhedron 19 (2000) 1719.
We are grateful to the Bu-Ali Sina for a Grant and Mr.
Zebarjadian for recording the NMR spectra.
[37] M. Kalyanasundari, K. Panchanatheswaran, V. Parthasarathi, W.T.
Robinson, H. Wen, Acta Crystallogr. 50 (1994) 1738.
[38] J.E. Huheey, Inorganic Chemistry Principles of Structure and
Reactivity, 2nd ed., Harper Int. Ed., New York, 1978, p. 233.
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