J. CHEM. SOC., CHEM. COMMUN., 1995 223
Synthesis and Crystal Structure of the First 6a-Thiathiophthen Metal Complex
[ M O ( C O ) ~ P P ~ ~ I ~ ( F L - C ~ H ~ S ~ )
Kuang-Hway Yih, Ying-Chih Lin,* Gene-Hsiang Lee and Yu WangDepartment of Chemistry, National Taiwan University, Taiwan 106, Republic of China
The first 6a-thiathiophthen metal complex was prepared by treating M(CO)5[PPh2CS2CH2C=CH] with a catalytic amount of secondary amine or tertiary amine; the structure of the 6a-thiathiophthen molybdenum complex is confirmed by an X-ray diffraction analysis.
With their unusual11 long S-S distances and possible aromatic properties of the two fused five-membered rings, the 6a- thiathiophthen (3,3a,4-trithiopentalene) derivatives1 have at- tracted considerable attention. Methods for the synthesis of 6a- thiathiophthen2 and arylthio- or alkylthio-derivatives3 using various thionation reagents such as S, H2S and P2S5 have been reported. Furthermore, much work has been done on the bonding: structure,' reactions6 and electron density deforma- tion7 studies on 6a-tliiathiophthen and its derivatives. However, no 6a-thiathiophthen metal complex has been reported. Here we report the high yield synthesis and the structure determination of the first 6a-thiathiophthen metal complex, which was prepared from the metal complex containing the diphenyl(S- prop-2-ynyl-dithiofcmnato)phosphine ligand.8
Treatment of
M(('0)5[PPh2(CS2CH2C=CH)]
(M = Mo, la; W, 1 b) with a catalylic amount of Et3N in CH2C12 yields the 6a- thiathiophthen metal complexes [M(CO)5PPh2]2(p-C5H2S3) (M = Mo, 2a; W, 2b) at room temperature (Scheme 1). Complex 2a is isolated as a red microcrystalline powder by recrystalliza- tion from hexane-CH2CI2 in ca. 85% yield. The spectroscopic? and analytical data of 2a are in agreement with the formulation. The FAB mass spectrum of 2a shows a base peak at mlz 721,corresponding to [ M O P P ~ ~ I ~ ( ~ - C ~ H ~ S ~ ) + , formed by loss of the ten CO groups from 2a. The IR spectrum of 2a shows two terminal carbonyl stretches at 2073 and 1924 cm-1, a typical pattern for a LM(C0)S unit in octahedral geometry. The 1H NMR spectrum of 2a exhibits a doublet at 6 7.90 (3JPpH = 7.2
Hz) attributed to the two equivalent methyne protons, and the corresponding 13C NMR signal is a doublet at 6 177.95 (2Jp-c = 11.3 Hz). The low field lH chemical shift is regarded as evidence for a strong ring current. The I3C NMR resonance of the 3a-carbon exhibits a triplet at 6 177.21 (3JpPc = 8.3 Hz). The 1H and 13C NMR spectra clearly imply Czv symmetry in 2a.
The molecular structure of this unusual complex 2a is confirmed by an X-ray diffraction study.$ An ORTEP drawing of 2a is shown in Fig. 1. The coordination geometry about the two molybdenum atoms can be described as distorted octahe- dral. Two metal atoms were bridged by two phosphorus atoms connected by a 6a-thiathivphthen unit. The two S-S distances [2.318(2) and 2.330(2) A] in complex 2a are significantly longer than the expected S-S single bond lengths (2.05
A)
but considerably shorter than sum of the sulfur van der Waals radii (3.7 A).9 Interestingly, in the crystal, 2a does not exhibit C2vsymmetry and the P2C5H2S3 unit is not planar. To our
Fig. 1 ORTEP drawinp for the complex [ M O ( C O ) ~ P P ~ ~ ] ~ ( ~ . - C ~ H ~ S ~ ) , 2a. Selected bond distances (A) and angles (") are as follows: Mo(1)-P(1) 2.528(2), Mo(2)-P(2) 2.540(2), P( 1)-C( 1 1) 1.855(4), P(2)-C( 15) 1.847(4), C( 1 1)-S( 1) 1.689(4), C( 13)-S(2) 1 .%36(4), C( 15)-S(3) 1.689(4), C( 1 1)- C(12) 1.352(5), C(12)-C(13) 1.415(5), C(13)-C(14) 1.399(5), C(14)-C(15) 1.371(5), S(l)-S(2) 2.318(2), S(2)-S(3) 2.330(2); C(1l)-P(1)-Mo(1)
224 J. CHEM. SOC., CHEM. COMMUN., 1995
/-
H 2 a M = M o b M = W 3 M = M o a R = PhCH2 4 M = W b R = E t\
iii l a M = M o b M = W \- no reactionScheme 1 Reagents and conditions: i, Et3N or Pri2NH or Et2NH or F-, CH2C12, 25 "C, 10 min; ii, RNH2 (R = PhCH2, Et), CH2C12, 25 "C, 1 min; iii, BunLi or ButOK or PhNH2, THF, 25 "C, 1 h
knowledge, complex 2a is the first example of metal-derivative of 6a-thiathiophthen.
In order to study the role of Et3N in the formation of 2a, other amines and Bu4NF were used to replace Et3N in the reaction. Complexes l a and l b were reacted with secondary amine (Pri2NH, Et2NH) or Bun4NF to give 2a and 2b, respectively, both in high yield. The rate of formation of 2 depends on the amine used and decreases in the order Et3N > Pri2NH > Et2NH > Bun4NF. No reaction was observed when 1 was reacted with BunLi, ButOK or PhNH2. But the reactions of 1 with several primary aliphatic amines (RNH2; R = PhCH2, Et) give M(CO)5PPh2CSNHR (M = Mo, R = PhCH2, Et; 3a-b; M = W, R = PhCH2, Et; 4a-b) and HCzCCH2SH in high yield, Scheme 1. Interestingly, complex 3 (or 4) is not the precusor that leads to 2. On the basis of the above-mentioned experi- ments, one can conclude that secondary or tertiary amines catalyse the formation of 2 but primary amines or strong bases do not. To probe the origin of the two methyn protons of 2a (from the terminal or the methylene of la), 2H-labelling experiment was carried out. Treatment of the terminally labelled [2Hl]la with Et3N afforded 2a with no 2H-labelling. In addition, when the reaction was monitored by the 3IP and lH NMR spectra, complex 2a was observed as the only product (yield 95% from integration of the 31P NMR spectrum) and no intermediate was observed. Attempts to trap possible inter- mediates by separate addition of PPh3, CS2, TCNE, Me1 or cyclopentadiene into the reaction of 1 with Et3N failed to produce any product other than 2. The metal carbonyl fragment is crucial for the formation of 2, since treatment of the analogous organic species Et2NC(S)SCH2C-CH with Et3N or PhCH2NH2 resulted in no reaction under the same reaction conditions. In the absence of R3N, dimerization of 1 gave a five- membered ring consisting of a C=S unit and the propynyl moiety.10
The reactivity of the 6a-thiathiophthen metal complexes and the mechanism for their formation are currently under in- vestigation.
We thank the National Science Council of Taiwan, the Republic of China for support.
Received, 2nd November 1994; Com. 4106708H
Footnotes
t Selected spectroscopic data: lH (300 MHz) and l3C{ l H ) (75 MHz) NMR (298 K, CDC13, relative to SiMe4, multiplicity, assignment, J in Hz) 31P (121.5 MHz) NMR (H3P04 external standard). la: IR (CH2C12, vco/cm-I): 2075(m), 1942(vs). 3lP NMR: 6 76.76. '€3 NMR: 6 2.18 (t, 1H, EcH, 4 J ~ - ~ = 2.68), 3.98 (d, 2H, s-cH2, 4 J ~ - ~ = 2.68), 7.47 (m, 6H, Ph), 7.67 (m, 4H, Ph). 13C NMR: 6 26.36 (S- CH2), 72.60 ( K H ) , 75.77 (CECH), 128.55 (d, meta-C of Ph, 3Jp-c = 9.60), 131.03 (s, para-C of Ph), 133.69 (d, ortho-C of Ph, 2 J p - ~ = 11.77), 133.67 (d, ipso-C of Ph, JpPc = 30.70), 205.35 (d, CO, 2 J p - ~ = 8.48), 209.84 (d, CS2, JPx = 26.10). MS (FAB, NBA, mlz): 539 (M+), [2Hl]lb (2H 98%): IR (CH2C12, vco/cm-l): 2072(m), 1940(vs). 31P 483 (M+ - 2CO). NMR: 6 59.95 (Jw-p = 237.0). 'H NMR: 6 3.96 (s, 2H, S-CHz), 7.45 (m, 6H, Ph), 7.69 (m, 4H, Ph). 2a: IR (KBr, vco/cm-l): 2073(m), 1924(vs). 31P NMR: 6 46.59. 'H NMR: 6 7.41 (m, 6H, Ph), 7.52 (m, 4H, Ph), 7.90 (d, 2H, CH, 3Jp-H = (d, CH, 2Jp-c = 11.3), 205.22 (d, cis-CO, 2JP-c = 9.0), 209.67 (d, PCS,
JP-,= = 24.8). MS (FAB, NBA, mlz): 1000.9 (M+), 972.9 (M+ - CO), 2b: IR (KBr, vCo/cm-l): 2068(m), 1931(vs). 31P NMR: 6 28.54 (JwPp = 249.6). 1H NMR: 6 7.41 (m, 6H, Ph), 7.52 (m, 4H, Ph), 7.91
3Jp-c = 8.3), 177.30(d, CH,2JpPC = 11.3), 196.80(d,cis-CO, 2 J p - ~ =
9.0). MS (FAB, NBA, mlz): 1176.2 (M+), 1148.0 (M+ - CO), 1064.0
7.2). 13C NMR: 6 128-134 (Ph), 177.21 (t, HCC, 3Jp-c = 8.3), 177.95
945 (M+ - 2CO), 916.9 (Mf - 3CO), 721.0 (M+ - lOC0).
(d, 2H, CH, 3 J p - ~ = 8.0). '3C NMR: 6 128-134 (Ph); 177.21 (t, HCC,
(M+ - 4CO), 1036.8 (M+ - 5CO), 1008.2 (M' - 6CO), 952.1 (M+ -
SCO), 925.2 (M+ - SCO), 896.2 (M+ - lOC0).
3a: 31P NMR: 6 63.47. 1H NMR: 6 4.87 (s, 2H, CH2), 7.14-7.65 (m, 15H, Ph). MS (FAB, NBA, mlz): 571.4 (M+), 543.4 (M+ - CO). 3.68 (9, 4H, CH2, JH-H = 7.3), 2.42 (b, lH, NH), 7.43-7.67 (m, ]OH, Ph)
.
4a: 31P NMR: 6 47.14 (JwPp = 256.4). lH NMR: 6 4.86 (s, 2H,
C H 2 ) , 7.29-7.68 (m, 15H, Ph), 7.91 (d, 2H, CH, 3Jp-H = 8.0). MS (FAB, NBA, mlz): 659.3 (M+), 631.3 (M+ - CO).
JHPH = 7.3), 3.95 (9, 4H, CH2, JHPH = 7.3), 7.30-7.63 (m, 10H, Ph)
.
$ Crystal data for 2a: C39H22010P2S3M02, space group P i , u =
9.042(7), b = 15.175(6), c = 16.554(8) A, a = 112.02(4), (3 =
96.38(4), y = 92.92(4)", V = 2082.2(21)
A3,
Z = 2, Dcalcd = 1.596g ~ m - ~ , p = 8.603 cm-1, observed reflections 4298, 20,,, = 45.0'. An absorption correction has been carried out. The structure was solved by Patterson synthesis then refined via standard least-squares and difference Fourier techniques. Non-hydrogen atoms were refined by using anisotropic thermal parameters. Total number of parameters: 506.
R = 0.028,RW = 0.029; GOF = 1.36, AF = 0.51, -0.48 e A3; Atomic coordinates, bond lengths and angles, and thermal parameters have been deposited at the Cambridge Crystallographic Data Centre. See Information for Authors, Issue No. 1.
3b: 31P NMR: 6 62.38. 'H NMR: 6 1.14 (t, 6H, CH3, J H - H = 7.3),
4b: 3'P NMR: 6 46.30 (Jw-p = 257.6). 'H NMR: 6 1.19 (t, 6H, CH3,
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![Fig. 1 ORTEP drawinp for the complex [ M O ( C O ) ~ P P ~ ~ ] ~ ( ~ . - C ~ H ~ S ~ ) , 2a](https://thumb-ap.123doks.com/thumbv2/9libinfo/8670852.195987/1.891.84.807.652.1106/fig-ortep-drawinp-complex-m-o-c-o.webp)
