Isolation and characterization of [Fe2(CO)6Se2{μ-(CO)3Cr(η 5-C5(H)(CH2Ph)(Ph)(OEt)}], [(CO)6Fe2{μ-EC(Ph)=C(E′)C(H)(OEt)}]2 and [(CO)6F

Article abstract of DOI:10.1016/S0022-328X(98)00646-9

Thermolysis of the trimetallic adducts [(CO)₆Fe₂EE′{μ-C(Ph)=C-C(OEt)=Cr(CO) ₅}] 1a,b (1a: E=E′=Se; 1b: E=S, E′=Te) in refluxing THF yield the following complexes: [Fe₂(CO)₆EE′{μ-(CO)₃Cr(η <

Full text of DOI:10.1016/S0022-328X(98)00646-9

Journal of Organometallic Chemistry 566 (1998) 159–164
Isolation and characterization of
[Fe2(CO)6Se2{v-(CO)3Cr(p5-C5(H)(CH2Ph)(Ph)(OEt)}],
[(CO)6Fe2{v-EC(Ph)ꢀC(E%)C(H)(OEt)}]2 and
[(CO)6Fe2{v-SC(H)(Ph)C(Te)ꢀC(H)(OEt)}] from the thermolysis of
Fischer carbene adducts [(CO)6Fe2EE%{v-C(Ph)ꢀC–C(OEt)ꢀCr(CO)5}]
(E, E%=Se and E=S, E%=Te)
Pradeep Mathur a,*, Sundargopal Ghosh a, Amitabha Sarkar b, Arnold L. Rheingold c,
Ilia A. Guzei c
a Department of Chemistry, Indian Institute of Technology, Powai, Bombay 400076, India
b Di6ision of Organic Chemistry (Synthesis), National Chemical Laboratory, Pune 411008, India
c Department of Chemistry, Uni6ersity of Delaware, Newark, DE 19716, USA
Received 23 March 1998; received in revised form 28 April 1998
Abstract
Thermolysis of the trimetallic adducts [(CO)6Fe2EE%{v-C(Ph)ꢀC–C(OEt)ꢀCr(CO)5}] 1a,b (1a: E=E%=Se; 1b: E=S, E%=Te)
in refluxing THF yield the following complexes: [Fe2(CO)6EE%{v-(CO)3Cr(p5-C5(H)(CH2Ph)(Ph)(OEt)}], (2: E=E%=Se);
[(CO)6Fe2{v-EC(Ph)ꢀC(E%)C(H)(OEt)}]2, (3a: E=E%=Se; 3b: E=S, E%=Te) and [(CO)6Fe2{v-EC(H)(Ph)C(E%)ꢀC(H)(OEt)}], (4:
E=S, E%=Te), where the product formation depends on the nature of chalcogen atoms present in the trimetallic adducts 1a and
1b. All products have been characterized by IR and 1H-, 13C-, 77Se- and 125Te-NMR spectroscopy and structural types were
unequivocally established by X-ray crystallographic analysis of compounds 3a and 4. © 1998 Elsevier Science S.A. All rights
reserved.
Keywords: Iron; Carbene; Cluster; X-ray diffraction
1. Introduction
([1]a). The metal–carbene fragment remains intact in
the trimetallic adduct [(CO)6Fe2EE%{v-C(Ph)ꢀC–
C(OEt)ꢀCr(CO)5}] (E=S, Se; E%=Se, Te), and so does
the cluster unit. As a result of cis-addition, the resultant
olefin has a fixed geometry where the phenyl ring resides
close to the Fischer carbene function. Such spatial
disposition of phenyl group may facilitate dissociation
of a CO ligand from Cr or W, leading to coordinatively
unsaturated intermediates. In order to explore possible
generation and fate of such reactive intermediates,
thermolysis of these adducts is under study. In a pre-
liminary report, we described the isolation and struc-
tural characterisation of an unusual annulated product
We recently reported that the chalcogen stabilized
diiron compounds [Fe2(v-EE%)(CO)6] (where E or E%=
S, Se or Te) add almost instantly to the triple bond of
carbene complexes, [(CO)5MꢀC(OEt)(CꢁCPh) (where
MꢀCr, W) [1]. In case of mixed chalcogen compounds
(E"E%), such addition to the acetylenic triple bond of
the Fischer carbene complex is highly regioselective
* Corresponding author. Fax: +91 22 5783480; e-mail:
mathur@ether.chem.iitb.ernet.in
0022-328X/98/$19.00 © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00646-9

160
P. Mathur et al. / Journal of Organometallic Chemistry 566 (1998) 159–164
Scheme 1.
[Fe2(CO)6Se2{v-(CO)3Cr(p5-C5(H)(CH2Ph)(Ph)(OEt)}]
obtained from the thermolysis reaction of
[(CO)6Fe2Se2{v-C(Ph)ꢀC–C(OEt)ꢀCr(CO)5}] [2]. In
this report, we describe in detail all the products ob-
tained from the thermolysis of [(CO)6Fe2Se2{v-
C(Ph)ꢀC–C(OEt)ꢀCr(CO)5}] (1a) and [(CO)6Fe2-
STe{v-C(Ph)ꢀC–C(OEt)ꢀCr(CO)5}] (1b).
distinct doublet of quartets typical of an ethoxy group
attached to a chiral centre. The 13C-NMR spectrum
indicates absence of any olefinic carbon, the most
downfield of aliphatic carbon signals is shown to be
attached to a hydrogen (presumably the proton at l
3.16 ppm). Though both 1H- and 13C-NMR spectra
suggest a symmetrical dimeric structure, an unambigu-
ous assignment is based on the crystal structure analysis
of 3a.
Red crystals of 3a were grown from hexane solvent at
−4°C and a single crystal X-ray diffraction analysis
was carried out. Its molecular structure is shown in Fig.
1.
2. Results and discussion
The preparation and characterisation of the start-
ing
materials
[(CO)6Fe2EE%{v-C(Ph)ꢀC–C(OEt)ꢀ
The crystal structure reveals that, it is in essence, a
symmetrical, dimeric compound derived from two
molecules of the starting material. The two chiral cen-
tres have a R/S relationship. Among the selenium-car-
bon bond distances, the phenyl carbon forms a longer
Cr(CO)5}] (1a, b) (1a: E, E%=Se; 1b: E=S; E%=Te)
have been described in detail earlier [1]. Thermolysis of
individual complexes 1a and 1b are carried out by
refluxing their THF solutions for 2 h, leading to the
formation of known [Fe2(CO)6Se2{v-(CO)3Cr(p5-
C5H(CH2Ph)(Ph)(OEt)}] (2) [2] and [(CO)6Fe2{v-
SeCPhꢀCSeC(H)(OEt)}]2 (3a) from 1a, and of
˚
bond (C(13)–Se(2) (1.972 (5) A) than the other carbon
[(CO)6Fe2{v-(S)CPhꢀCTeC(H)(OEt)}]2
(3b)
and
[(CO)6Fe2{v-SC(H)(Ph)C(Te)ꢀC(H)(OEt)}] (4) from 1b
(Scheme 1).
Identification of 2 is based on comparison of its
spectral features with those reported earlier [2]. Com-
pounds 3a, 3b, and 4 have been characterised by IR
1
and H-, 13C-, 77Se- and 125Te-NMR spectroscopy, and
structures of 3a and 4 have been established crystallo-
graphically. The IR spectra of all four products show
bands due to terminal carbonyls only; the w(CO)
stretching patterns for 3a and 3b are identical.
1
The H-NMR spectrum of compound 3a features a
non-exchangeable singlet at l 3.16 ppm and signals in
the aliphatic region due to ethoxy group. The
methylene protons of the ethoxy group appear as two
Fig. 1. Molecular structure of [(CO)6Fe2{v-SeC(Ph)ꢀC(Se)C(H)-
(OEt)}]2 (3a).

P. Mathur et al. / Journal of Organometallic Chemistry 566 (1998) 159–164
161
of the complex in the asymmetric unit of 4. The molec-
ular structure of one molecule of 4 is shown in Fig. 2.
The crystal structure reveals an exocyclic enol ether
function anchored to the chalcogenide cluster. The
ethoxy group occupies a syn position with respect to the
phenyl ring. It consists of a Fe2STe butterfly core and a
vinylic ether unit, attached to the wing-tip selenium and
sulphur atom. The olefinic bond distance in 4, (C(9)–
˚
C(10) 1.33(2) (A) is somewhat longer than the corre-
˚
sponding olefinic bond distance of 1.28(1) (A) in
[(CO)6Fe2{v-SeC(Ph)(H)C(Se)ꢀC(H)(OEt)}] [4]. The
S(1)–C(11)–C(12) bond angle in 4, 107.3(10)° is similar
to the corresponding bond angle, Se(1)–C(7)–C(9) of
105.9(8)°
(OEt)}] [4].
in
[(CO)6Fe2{v-SeC(Ph)(H)C(Se)ꢀC(H)-
Fig. 2. Molecular strructure of [(CO)6Fe2{v-SC(H)Ph-C(Te)ꢀ
C(H)(OEt)}] (4).
Table 1
Crystallographic data for 3a and 4
attached to the second Se atom of the rare Fe2Se2 unit,
C(21)–Se(4) (1.929(5) A).
3a
4
˚
Formula
Formula weight 1193.76
C34H22Fe4O14Se4
C17H12Fe2O7Ste
599.63
A normal carbene dimerization reaction would have
resulted in a tetrasubstituted, symmetrical olefin, [3]
and therefore, the novel product obtained here can be
viewed as a formal hydrogenated derivative of such an
olefin. The symmetry of its structure explains the highly
symmetrical 13C-NMR spectrum of this compound,
each signal represents two carbons of the molecule. The
chirality of the saturated carbon is responsible for the
diastereotopicity of the ethoxy methylene protons as
(
Space group
P21/c
P1
˚
a (A)
15.831 (5)
16.142 (6)
16.573 (7)
—
95.26 (2)
—
4217 (2)
4
1.880
7.781 (3)
20.148 (9)
20.44 (2)
86.13 (6)
82.09 (5)
82.99 (5)
3146 (3)
6
˚
b (A)
˚
c (A)
h (°)
i (°)
k (°)
3
˚
V (A )
Z
1
Dcalc. (g cm3)
v(Mo–Kh)
1.899
28.80
observed in the H-NMR spectrum. Interestingly, the
48.62
chemical shift difference of these geminally non-equiva-
lent methylene protons in complex 3b, is not very large,
and the signal therefore appears as a complex multiplet.
The 13C-NMR spectrum of complex 3b also reflects its
symmetrical dimeric structure, each signal representing
two carbons. The origin of hydrogen atoms in these
complexes is unclear at present.
(cm−1
)
F(000)
Crystal size
(mm)
2q range for
data collection
(°)
2312
0.40×0.30×0.10
1740
0.30×0.20×0.10
48
48
Limiting indices −15h518, −15k5 −85h58, −215k5
The 77Se-NMR spectrum of compound 3a shows two
signals, a singlet and a doublet with Se–H coupling,
consistent with a three-bond coupling with the hydro-
gen atom. The 125Te-NMR spectrum of 3b shows a
single peak, in the region normally associated with
v3-Te ligand.
Also obtained from the thermolysis of 1b is
[(CO)6Fe2{v-SC(H)(Ph)C(Te)ꢀC(H)(OEt)}] (4). The
1H-NMR spectrum shows four signals, a triplet and a
quartet for the ethoxy protons and two doublets, for
the C(H)Ph and C(H)OEt) protons. The more
downfield of these two also shows 125Te satellites and
therefore can be assigned to C(H)(OEt) proton. The
13C- and 125Te-NMR spectra are consistent with the
structure of 4. For an unambiguous structure elucida-
tion, red crystals of 4 were grown from hexane solvent
at 5°C and a single crystal X-ray diffraction analysis
was carried out. There are three independent molecules
19, −195l519
8805
21, −15l521
10 409
Reflections col-
lected
Independent
reflections
Temp (K)
Absorption cor- Semiempirical
rection
T(max)/T(min)
7340 (Rint=0.0558)
8232 (Rint=0.1405)
244 (2)
248 (2)
Empirical
1.000/0.813
Siemens P4
1.000/0.647
Diffractometer
Radiation (Mo– u=0.71073
˚
Kh) (A)
Goodness-of-fit
0.801
1.029
on F2
−
˚
Largest diff.
peak and hole
R(F), %a
0.519 and −0.702 eA
3
3.85
9.65
1.467 and −1.317
−3
˚
eA
6.76
14.22
R(wF2), %a
a Quantity minimized=R(wF2)=ꢀ[w(Fo2−Fc2)2]/ꢀ[(wF2o)2]1/2
ꢀD/ꢀ(Fo), D=ꢁ(Fo−Fc)ꢁ.
; R=

162
P. Mathur et al. / Journal of Organometallic Chemistry 566 (1998) 159–164
Table 2
3. Experimental section
Atomic coordinates (×104) and equivalent isotropic displacement
3
˚
parameters (A×10 ) for 3a
All reactions and other manipulations were carried
out under an argon or nitrogen atmosphere, using
standard Schlenk techniques. Solvents were deoxy-
genated immediately prior to use. Reactions were mon-
itored by FT-IR spectroscopy and thin-layer
chromatography. Infrared spectra were recorded on a
Nicolet-Impact 400 FTIR spectrometer as n-hexane
solutions in sodium chloride cell at 0.1 mm path length.
Elemental analyses were performed using a Carlo Erba
1106 automatic analyzer. 1H-, 13C-, 77Se- and 125Te-
NMR spectra were recorded on a Varian VXR 300S
spectrometer in CDCl3 at 25°C. The operating fre-
quency for 77Se-NMR was 57.23 MHz with a pulse
width of 15 ms and a delay of 1.0 s and operating
frequency for 125Te was 94.70 MHz with pulse width of
9.5 ms and a delay of 1 s. 77Se-NMR spectra were
referenced to Me2Se (l=0 ppm) and 125Te-NMR spec-
tra were referenced to Me2Te (l=0 ppm).
Chromium hexacarbonyl and phenylacetylene were
purchased from Aldrich and these were used without
further purification. The homo- and mixed-chalco-
genide iron carbonyl clusters [Fe2(v-Se2)(CO)6] [5] and
[Fe2(v-STe)(CO)6], [6] h,i-unsaturated mixed chalco-
genide carbene complexes [(CO)6Fe2EE%{v-C(Ph)ꢀC–
C(OEt)ꢀCr(CO)5}], (1a: E=E%=Se; 1b: E=S, E%=Te)
[1] and the alkynyl Fischer carbene complexes
[(CO)5MꢀC(OEt)(CꢁCPh)] (MꢀCr, W) [7] were pre-
pared as previously reported.
Atom
x
y
z
Uaeq
47(1)
Fe(1)
Fe(2)
Fe(3)
Fe(4)
Se(1)
Se(2)
Se(3)
Se(4)
O(1)
O(2)
O(3)
O(4)
O(5)
O(6)
O(7)
O(8)
O(9)
O(10)
O(11)
O(12)
O(13)
O(14)
C(1)
14 955.8(5)
14 789.4(5)
8988.4(5)
9030.1(5)
13 622.6(4)
14 919.4(4)
9216.0(4)
10 206.5(3)
14 385(4)
15 034(3)
16 787(3)
14 639(3)
14 001(4)
16 576(3)
12 071(2)
11 869(2)
8505(3)
6676.6(6)
7818.5(6)
7953.4(6)
6566.3(6)
7289.9(4)
6413.3(4)
6725.2(4)
7476.7(4)
5091(4)
7667(3)
6423(4)
9297(3)
8494(4)
8101(4)
7883(3)
6440(2)
8850(3)
9205(4)
8077(4)
6913(4)
4976(3)
6106(3)
5713(6)
7283(4)
6539(5)
8718(4)
8235(5)
7977(4)
4674(4)
4001(4)
4017(4)
4724(4)
5405(4)
5381(4)
6092(4)
6491(3)
6424(4)
5707(4)
5828(5)
7105(4)
8532(4)
9334(4)
7028(4)
6718(4)
6388(4)
6895(4)
6620(5)
5862(5)
5338(4)
5593(4)
8515(4)
8715(5)
8029(4)
6782(5)
5580(4)
6285(4)
3417.0(5)
2377.0(6)
1441.9(5)
2127.8(5)
3002.2(4)
2008.9(4)
724.9(4)
2256.1(4)
4000(4)
4895(3)
3612(3)
3364(3)
853(3)
44(1)
42(1)
37(1)
39(1)
42(1)
39(1)
39(1)
116(2)
81(2)
114(3)
85(2)
102(2)
98(2)
38(1)
38(1)
81(2)
106(2)
97(2)
92(2)
95(2)
62(1)
72(2)
55(2)
65(2)
48(2)
64(2)
61(2)
36(2)
43(2)
45(2)
44(2)
27(2)
32(2)
32(2)
28(1)
32(2)
51(2)
103(3)
35(2)
53(2)
71(2)
34(2)
30(1)
33(2)
45(2)
59(2)
55(2)
48(2)
40(2)
56(2)
69(2)
56(2)
58(2)
57(2)
43(2)
2176(3)
1892(2)
2842(2)
2854(3)
529(4)
9820(4)
7302(3)
8758(3)
9884(3)
550(3)
3806(3)
2364(4)
1784(3)
3787(5)
4322(4)
3533(4)
2979(4)
1433(5)
2250(4)
1459(3)
953(4)
7250(3)
14 624(5)
14 995(4)
16 074(4)
14 714(4)
14 304(5)
15 877(4)
13 186(3)
13 107(4)
13 447(4)
13 828(4)
13 909(3)
13 588(3)
13 718(3)
13 172(3)
12 222(3)
12 028(4)
11 694(6)
11 824(3)
11 969(4)
12 191(5)
10 864(3)
10 453(3)
10 871(3)
11 056(45)
11 586(4)
11 918(4)
11 719(4)
11 192(4)
8698(4)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
2123(4)
−23(4)
478(3)
3.1. Thermolysis of
[(CO)6Fe2Se2{v-C(Ph)ꢀC–C(OEt)ꢀCr(CO)5}]
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(28)
C(29)
C(30)
C(31)
C(32)
C(33)
C(34)
1231(3)
1796(3)
2199(3)
2090(3)
3309(4)
4120(4)
1562(3)
1310(4)
1708(4)
1435(3)
777(3)
A
solution
of
[(CO)6Fe2Se2{v-C(Ph)ꢀC–
C(OEt)ꢀCr(CO)5}] (1a) (1 g, 1.26 mmol) in THF (10
ml) was refluxed for 2 h. The reaction was monitored
by TLC, and refluxing stopped when all the starting
material was consumed. The solution was filtered
through Celite to remove the insoluble materials. After
removal of solvent from the filtrate, the residue was
subjected to chromatographic work-up using silicagel
TLC plates. Elution with hexane/dichloromethane (9:1
v/v) mixture afforded the following compounds, in
order of polarity: brown [Fe2(CO)6Se2{v-(CO)3Cr(p5-
C5H(CH2Ph)(Ph)(OEt)}] (2) [2] (0.26 g, 25%) and red
[(CO)6Fe2{v-SeCPhꢀCSeC(H)(OEt)}]2 (3a) (0.28 g,
19%).
91(3)
−541(3)
−1107(4)
−1047(4)
−456(4)
122(4)
3a: IR (cm−1): 2067 (s), 2031 (vs), 1999 (s), 1989 (s),
1978 (w), 1949 (w). 1H-NMR (ppm): l 1.44 (6H, t,
CH3), 3.16 (2H, s, CH), 3.22 (2H, dq, J=6.9, 1.5 Hz,
OCH2), 3.42 (2H, dq, J=7, 1.5 Hz, OCH2), 6.62–7.30
(10H, m, 2C6H5). 13C-NMR (ppm): l 15.4 (CH3, JC–
H=127.4 Hz), 65.6 (OCH2, JC–H=140 Hz), 80.7
2287(5)
892(5)
911(4)
3151(4)
2280(4)
1900(4)
9504(5)
7954(5)
8857(4)
9546(4)
7941(4)
a
Ueq is defined as one third of the trace of the orthogonalised Uij
(CH(OEt),
JC–H=143.6 Hz), 125.8–129.3 (C6H5),
tensor.
136.2 (quat C in phenyl ring), 147.2 (SeCC(OEt), 150

P. Mathur et al. / Journal of Organometallic Chemistry 566 (1998) 159–164
163
Table 3
Table 3 (continued)
Atomic coordinates (×104) and equivalent isotropic displacement
5
Uaeq
83(4)
˚
parameters (A×10 ) for 4
Atom
x
y
z
Atom
x
y
z
Uaeq
41(1)
O(202)
O(203)
O(204)
O(205)
O(206)
O(207)
C(201)
C(202)
C(203)
C(204)
C(205)
C(206)
C(207)
C(208)
C(209)
C(210)
C(211)
C(212)
C(213)
C(214)
C(215)
C(216)
C(217)
12 562(17)
596(6)
2252(6)
400(6)
3821(7)
4325(7)
6435(6)
4645(7)
6139(7)
5375(5)
5379(9)
4260(9)
15 420(17)
10 105(19)
8072(17)
6111(17)
10 939(13)
13 692(22)
12 527(19)
14 305(22)
9808(21)
8576(22)
7412(24)
9076(30)
10 807(28)
11 159(16)
10 911(17)
10 323(19)
8555(18)
8223(24)
6611(27)
5398(26)
5715(25)
7331(20)
85(4)
86(4)
83(4)
86(4)
50(3)
54(5)
54(5)
67(5)
52(4)
56(5)
55(4)
94(7)
72(6)
72(6)
34(3)
44(4)
36(3)
63(5)
71(6)
80(7)
82(6)
55(4)
Te(1)
Fe(1)
Fe(2)
S(1)
O(1)
O(2)
O(3)
O(4)
O(5)
O(6)
O(7)
C(1)
C(2)
C(3)
C(4)
C(5)
7284(1)
7161(3)
4427(3)
5022(5)
5781(18)
4559(1)
5149(1)
5163(1)
4501(2)
5941(7)
4350(7)
6277(6)
6277(6)
6026(6)
4508(7)
2477(5)
5652(9)
4667(8)
5792(8)
5825(9)
5690(8)
4749(9)
1789(11)
1928(8)
3088(8)
3635(7)
3638(6)
3247(7)
3000(8)
2645(9)
2520(10)
2748(10)
3093(8)
1319(1)
1758(1)
1920(1)
1128(2)
910(7)
847(1)
1908(1)
1347(1)
2229(2)
3051(7)
2408(7)
1154(7)
375(6)
43(1)
44(1)
41(1)
82(4)
82(4)
90(4)
78(4)
83(4)
77(4)
58(3)
59(5)
52(4)
55(4)
60(5)
60(5)
61(5)
108(8)
69(5)
49(4)
41(4)
43(4)
38(4)
55(5)
80(7)
86(7)
85(7)
62(5)
41(1)
42(1)
41(1)
43(1)
98(5)
75(4)
78(4)
76(4)
84(4)
76(4)
70(4)
53(4)
56(5)
57(5)
51(4)
51(4)
56(5)
56(5)
95(8)
51(4)
41(4)
41(4)
42(4)
57(5)
67(5)
73(6)
74(6)
44(4)
43(1)
43(1)
43(1)
39(1)
81(4)
576(7)
2151(7)
4187(5)
884(8)
934(8)
1936(9)
849(8)
10 124(17)
8845(17)
4963(17)
1950(17)
1943(16)
7642(14)
6281(23)
8981(22)
8213(21)
4735(20)
2937(23)
2930(23)
6710(30)
8159(25)
7711(19)
6923(18)
5844(18)
4318(18)
3716(22)
2269(30)
1472(27)
2049(23)
3514(20)
3417(1)
4542(10)
6067(8)
4967(9)
5851(8)
6158(10)
5789(9)
5682(9)
5418(7)
4782(7)
4674(7)
4041(9)
3947(10)
4478(14)
5098(12)
5212(9)
2233(7)
733(6)
956(8)
1891(8)
4867(11)
4746(8)
3592(6)
3035(6)
3006(7)
3379(6)
3561(8)
3922(8)
4077(9)
3873(10)
3525(8)
1365(5)
2595(9)
2222(9)
1458(9)
757(9)
1888(9)
961(9)
593(12)
954(9)
1051(8)
1343(7)
1990(8)
2075(8)
2711(7)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
Te(11)
Fe(11)
Fe(12)
S(101)
O(101)
O(102)
O(103)
O(104)
O(105)
O(106)
O(107)
C(101)
C(102)
C(103)
C(104)
C(105)
C(106)
C(107)
C(108)
C(109)
C(110)
C(111)
C(112)
C(113)
C(114)
C(115)
C(116)
C(117)
Te(21)
Fe(21)
Fe(22)
S(201)
O(201)
a
Ueq is defined as one third of the trace of the orthogonalised Uij
tensor.
2807(10)
2291(13)
1683(12)
1580(10)
7620(1)
8752(1)
8189(1)
8987(2)
9237(8)
8151(7)
9931(7)
7386(6)
9186(7)
7462(6)
7874(6)
9033(9)
8382(9)
9482(10)
7706(8)
8801(8)
7749(9)
7009(13)
7391(12)
7626(9)
7978(7)
8629(7)
8645(7)
8074(9)
8084(9)
8645(11)
9214(11)
9199(8)
5929(1)
5469(1)
4898(1)
4559(2)
5699(7)
(SCPh), 209.3 {Fe(CO)3}. 77Se-NMR (ppm): l 534 (d,
Se–H=6.1 Hz, SeC(H)(OEt), 542 {s, SeC(Ph)}. M.p.
J
170–172°C. Anal. Calc. (Found) for Fe4Se4C34O14H22:
C, 34.19 (34.22), H, 1.84 (1.85%).
3383(3)
635(3)
1162(5)
3.2. Thermolysis of
[(CO)6Fe2STe{v-C(Ph)ꢀC–C(OEt)ꢀCr(CO)5}]
6325(18)
5255(15)
2110(18)
1367(17)
−1687(18)
−1976(15)
3472(15)
5200(23)
4559(20)
2624(20)
1064(21)
−781(22)
−957(20)
2438(43)
3887(29)
3674(21)
2951(18)
1827(9)
2855(6)
2513(6)
3121(6)
2712(6)
1505(6)
−792(5)
1224(8)
2431(8)
2202(9)
2636(8)
2392(8)
1650(9)
A
solution
of
[(CO)6Fe2STe{v-C(Ph)ꢀC–
C(OEt)ꢀCr(CO)5}] (1b) (0.7 g, 0.88 mmol) in THF (10
ml) was refluxed for 2 h. The reaction was monitored
by TLC, and refluxing was stopped when all the start-
ing material was consumed. The solution was filtered
through Celite to remove the insoluble materials. After
removal of solvent from the filtrate, the residue was
subjected to chromatographic work-up using silicagel
TLC plates. Elution with hexane/dichloromethane (9:1
v/v) mixture afforded the following compounds, in
−1355(13)
−1288(9)
−157(7)
342(8)
order
of
polarity:
red
[(CO)6Fe2{v-(5)CPhꢀ
CTeC(H)(OEt)}]2 (3b) (0.09 g, 9%) and yellow
[(CO)6Fe2{v-SC(H)(Ph)C(Te)ꢀC(H)(OEt)}] (4) (0.08 g,
17%).
300(7)
203(19)
−51(7)
−49(8)
−364(10)
−672(10)
−688(9)
−368(6)
2121(1)
1488(1)
1489(1)
2119(2)
471(6)
−573(19)
−2040(22)
−2778(22)
−2010(24)
−487(19)
11 546(1)
9428(3)
12 563(3)
10 235(5)
14 471(17)
3b: IR (cm−1): 2064 (s), 2028 (vs), 1998 (s) 1986 (s),
1973 (w), 1943 (w). 1H-NMR (ppm): l 1.41 (6H, t,
CH3), 2.77 (2H, s, CH), 3.23 (4H, m, OCH2), 6.62–7.38
(10H, m, 2C6H5). 13C-NMR (ppm): l 15.7 (CH3, JC–
H=127.4 Hz), 65.1 (OCH2, JC–H=141 Hz), 80.74
(CH(OEt),
JC–H=143.6 Hz), 126.1–129.1 (C6H5),
132.3 (CTe), 136.8 (quat C in phenyl ring), 164
(CS(Ph), 209.7 {Fe(CO)3}. 125Te-NMR (ppm): l 804.

164
P. Mathur et al. / Journal of Organometallic Chemistry 566 (1998) 159–164
Table 4
Table 5
˚
˚
Selected bond distances (A) and bond angles (°) for 3a
Selected bond distances (A) and bond angles (°) for one of the
independent molecule in the assymetric unit of 4
˚
Bond length (A)
˚
Fe(1)–Fe(2)
Fe(3)–Fe(4)
Fe(1)–Se(1)
Fe(2)–Se(1)
Fe(3)–Se(4)
Fe(4)–Se(4)
2.521(2)
2.509(2)
2.3751(12)
2.3590(12)
2.3779(12)
2.3666(12)
Se(1)–C(14)
Se(4)–C(21)
C(15)–O(8)
C(13)–C(14)
C(15)–C(18)
C(22)–C(21)
1.942(5)
1.929(5)
1.413(6)
1.310(7)
1.507(7)
1.317(7)
Bond length (A)
Fe(1)–Te(1)
Fe(1)–S(1)
Fe(2)–Te(1)
Fe(1)–Fe(2)
Fe(1)–S(1)
2.528(3)
2.240(4)
2.520(3)
2.549(3)
2.240(4)
Fe(2)–S(1)
2.237(5)
2.091(13)
1.47(2)
1.33(2)
1.49(2)
Te(1)–C(10)
C(10)–C(11)
C(9)–C(10)
C(11)–C(12)
Bond angle (°)
Bond angle (°)
Fe(1)–Se(1)–Fe(2) 64.35(4)
Fe(2)–Se(2)–Fe(1) 64.41(4)
Fe(3)–Fe(4)–Se(3) 57.50(3)
Fe(3)–Se(4)–Fe(4) 63.86(4)
Se(4)–C(21)–C(18) 118.0(4)
Fe(1)–Se(2)–C(13) 99.2(2)
Se(1)–C(14)–C(15) 115.5(4)
Fe(4)–Se(4)–C(21) 100.1(2)
Fe(2)–Te(1)–Fe(1) 60.65(8)
Te(1)–Fe(1)–Fe(2) 59.53(8)
Fe(2)–Te(1)–C(10) 95.84(4)
Fe(1)–Te(1)–C(10) 93.2(4)
Te(1)–C(10)–C(9) 117.4(11)
S(1)–C(11)–C(12) 107.3(10)
Te(1)–C(10)–C(11) 117.6(11)
C(9)–C(10)–C(11) 124.9(13)
S(1)–C(11)–C(10) 111.6(10)
Te(1)–Fe(2)–S(1)
Fe(2)–S(1)–Fe(1)
81.74(13)
69.42(13)
Te(1)–Fe(2)–Fe(1) 59.82(8)
Fe(2)–Fe(1)–S(1)
Te(1)–Fe(1)–S(1)
55.24(12)
81.52(13)
M.p. 178–180°C. Anal. Calc. (Found) for
Fe4Se2Te2C34O14H22: C, 34.14 (34.30), H, 1.84 (2.10%).
4: IR (cm−1): 2066 (s), 2029 (vs), 1998 (s), 1989 (m).
1H-NMR (ppm, CDCl3): l 0.96 (3H, t, CH3), 3.74 (2H,
4. Supplementary material available
q, OCH2), 4.49 (1H, d, C(H)S), 6.62 (1H, d, JTe–H
=
11.8 Hz, ꢀC(H)(OEt)), 7.10–7.28 (5H, m, C6H5). 13C-
NMR (ppm, CDCl3): l 15.3 (CH3, JC–H=127. Hz),
Crystallographic details including fractional atomic
coordinates for hydrogen atoms, bond lengths and
bond angles and anisotropic displacement parameters
and the structure factor tables for 3a and 4 are avail-
able, upon request, from the authors.
60.1 (CH(Ph), JC–H=144 Hz), 69.1 (OCH2, JC–H
=
145.6 Hz), 127.5–128.3 (C6H5), 139.6 (s, ꢀCTe), 150.1
(ꢀCH, JC–H=180.6 Hz), 209.8 (Fe(CO)3). 125Te-NMR
3
(ppm, CDCl3): l 737 (d, JTe–H=12.2 Hz, ꢀCTe). M.p.
104–106°C. Anal. Calc. (Found) for Fe2STeC17O7H12:
C, 34.04 (34.30); H, 2.00 (2.24%).
Acknowledgements
S. Ghosh would like to thank the Council for Scien-
tific and Industrial Research, New Delhi, for a Senior
Research Fellowship.
3.3. Crystal structure determination of 3a and 4
Red crystals of 3a and 4 were selected and mounted
with epoxy cement to glass fibres. Single crystal X-ray
data were collected on Siemans P4 diffractometer by
using Mo–Kh radiation. The unit-cell parameters were
obtained by the least-squares refinement of the angular
settings of 24 reflections (2052q525°). Pertinent crys-
tallographic data of 3a and 4 are summarized in Table
1. The systematic absences in the diffraction data of 3a
and 4 are uniquely consistent for the reported space
groups. The asymmetric unit of 4 consists of three
crystallographically-independent, but chemically identi-
cal molecules. The structures were solved using direct
methods, completed by subsequent difference Fourier
syntheses and refined by full-matrix least-squares proce-
dures. Empirical absorption corrections for 4 was ap-
plied by using program DIFABS [8]. All non-H atoms
were refined with anisotropic displacement coefficients
and H atoms were treated as idealized contributions.
All software and sources of the scattering factors are
contained in the SHELXTL (5.3) program library (G.
Sheldrick, Siemans XRD, Madison, WI). Final frac-
tional atomic coordinates, selected bond lengths and
bond angles for 3a and 4 are listed in Tables 2–5.
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V.G. Puranik, Organometallics 16 (1997) 4392.
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