Organometallic complexes of iridium, palladium, chromium and iron from 2-phenyl-5(4H)-oxazolones - Organometallic labelled dipeptides

Article abstract of DOI:10.1002/(SICI)1099-0682(199804)1998:4<485::AID-EJIC485>3.0.CO;2-Y

Reactions of 2-phenyl-4-R-5(4H)-oxazolones (R = Me, CH₂Ph, CHMeEt) with [(η⁵-C₅Me₅)IrCl₂]₂ afforded the cyclometallated complexes (η-C₅Me₅)(Cl)Ir(L) (1-3) [L = 2-phenyl-4-R-5(4H)-oxazolone(C-o,N)], 2-Phenyl-5(4H)-oxazolone reacts with [(η⁵-C₅Me₅)IrCl₂]₂ and palladium(II) acetate to give complexes with a C-o,N-bridging oxazolone [(η⁵-C₅Me₅)(Cl)Ir] ₂(μ-Cl)(μ-L-H⁺) (4) and Pd₃-ac)₅(μ-L-H⁺) (5). 2-Phenyloxazolone anions were added to the π ligands of [(η⁵-C₆H₇)Fe(CO)₃]⁺ and [(η⁷-C₇H₇)Cr(CO)₃]⁺ to give the adducts 6-11. Dipeptide derivatives 12-18 were obtained by reaction of 1, 2 and by reaction of the adduct 6 from [(η⁵-C₆H₇)Fe(CO)₃]⁺ and the anion of 2-phenyloxazolone with α-amino acid esters. These reactions may be used for the labelling of peptides. Saponification of 15-18 yields the organometallic substituted peptide acids 19-22. Their dianions (deprotonation of COOH and peptide amide) were used as ligands towards (Ph₃P)₂PtCl₂ to yield the bimetallic complexes 23-25. The structures of 4, 5, 9 and 10 were determined by X-ray diffraction.

Full text of DOI:10.1002/(SICI)1099-0682(199804)1998:4<485::AID-EJIC485>3.0.CO;2-Y

FULL PAPER
Metal Complexes of Biologically Important Ligands, CII[᭛]
Organometallic Complexes of Iridium, Palladium, Chromium and Iron from
2-Phenyl-5(4H)-oxazolones ؊ Organometallic Labelled Dipeptides
Werner Bauera, Markus Prema, Kurt Polbornb[2], Karlheinz Sünkela[2], Wolfgang Steglichb, and Wolfgang Beck*a
Institut für Anorganische Chemie der Ludwig-Maximilians-Universitäta,
Meiserstraße 1, D-80333 München, Germany
Institut für Organische Chemie der Ludwig-Maximilians-Universitätb,
Karlstr. 23, D-80333 München, Germany
Received November 14, 1997
Keywords: 2-Phenyl-4-R-5(4H)-oxazolones / Iridium / Palladium / Platinum / Iron / Chromium / C-o,N-Bridging
2-phenyloxazolone / Peptide labelling
Reactions of 2-phenyl-4-R-5(4H)-oxazolones (R
CH2Ph, CHMeEt) with [(η5-C5Me5)IrCl2]2 afforded the cyclo- C6H7)Fe(CO)3]+ and the anion of 2-phenyloxazolone with α-
metallated complexes (η5-C5Me5)(Cl)Ir(L) (1Ϫ3) [L = 2-
amino acid esters. These reactions may be used for the label-
phenyl-4-R-5(4H)-oxazolone(C-o,N)]. 2-Phenyl-5(4H)-oxazo- ling of peptides. Saponification of 15Ϫ18 yields the organo-
lone reacts with [(η5-C5Me5)IrCl2]2 and palladium(II) acetate
metallic substituted peptide acids 19Ϫ22. Their dianions (de-
to give complexes with a C-o,N-bridging oxazolone [(η5- protonation of COOH and peptide amide) were used as li-
=
Me,
tion of 1, 2 and by reaction of the adduct 6 from [(η5-
C5Me5)(Cl)Ir]2(µ-Cl)(µ-L-H+) (4) and Pd3(µ-ac)5(µ-L-H+) (5). 2-
Phenyloxazolone anions were added to the π ligands of [(η5-
C6H7)Fe(CO)3]+ and [(η7-C7H7)Cr(CO)3]+ to give the adducts
6Ϫ11. Dipeptide derivatives 12Ϫ18 were obtained by reac-
gands towards (Ph3P)2PtCl2 to yield the bimetallic complexes
23Ϫ25. The structures of 4, 5, 9 and 10 were determined by
X-ray diffraction.
5(4H)-Oxazolones which can be considered as activated
α-amino acid derivatives are important intermediates and
starting materials in organic synthesis.[3] Recently, we re-
ported on some metal complexes with neutral 2-phenyl-
5(4H)-oxazolones.[4] In the following some cyclometallated
complexes from these oxazolones and the use of the delo-
calized oxazolone anion[5] as nucleophile for the addition
to π-coordinated ligands are described. Some of the com-
pounds obtained may be of use for the labelling of pep-
tides[6]
.
Results and Discussion
1. Cyclometallated Complexes
The reaction of the chloro-bridged iridium(III) complex
[Cp*IrCl2]2 with the substituted 2-phenyl-4-R-5(4H)-oxazo-
lones gave the complexes 1Ϫ3. Cyclometallation with
phenyl-containing donors has been observed for several
iridium complexes[7]
.
The complexes 1Ϫ3 contain an “asymmetric” metal
center which causes doubling of the 1H-NMR signals of the
C5Me5 ligands (1: 5:1; 2: 20:1; 3: 1:1), due to diastereoiso-
mer formation.
An unexpected complex 4 was obtained from the unsub- iridium atoms are bridged by a chlorine atom and a C-o,N-
stituted 2-phenyl-5(4H)-oxazolone and its structure was es- bound 2-phenyloxazolone ligand.
tablished by X-ray diffraction. In the complex 4 the two
In the five-membered ring ClϪIrϪCϪNϪIr the C atom
is situated outside the almost planar arrangment of the
other four atoms. The 1H-NMR spectrum of 4 exhibits only
[᭛] Part CI: Ref.[1]
.
Eur. J. Inorg. Chem. 1998, 485Ϫ493
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1998
1434Ϫ1948/98/0404Ϫ0485 $ 17.50ϩ.50/0
485

W. Bauer, M. Prem, K. Polborn, K. Sünkel, W. Steglich, W. Beck
FULL PAPER
Figure 1. Molecular structure of 4[a] in the crystal
Figure 2. Molecular structure of 5[a] in the crystal
[a]
˚
Selected bond lengths [A] and angles [°]: Ir2ϪN1 2.117(9),
Ir1ϪC11 2.152(12), N1ϪC13 1.29(2), N1ϪC11 1.461(14),
C11ϪC12 1.44(2), Ir2ϪCl2 2.446(3), Ir1ϪCl2 2.436(3);
N1ϪIr2ϪCl2 82.7(2), C11ϪIr1ϪCl2 80.4(3), C13ϪN1ϪC11
106.4(10), N1ϪIr2ϪCl2ϪIr1 3.53(0.27), Cl2ϪIr2ϪN1ϪC11
37.00(0.72), C11ϪIr1ϪCl2ϪIr2 110.45(0.17), N1ϪC13ϪC14Ϫ
C15 46.68(2.04).
[a]
˚
Selected bond lengths [A] and angles [°]: Pd3ϪO8 1.995(3),
Pd3ϪO11 2.002(3), Pd2ϪO12 2.087(3), Pd2ϪO10 2.019(3),
Pd2ϪC1 2.025(4), Pd1ϪN1 2.003(3), Pd1ϪO7 2.015(3), Pd1ϪO5
2.005(3); O11ϪPd3ϪO6 166.40(13), O12ϪPd2ϪC1 179.57(15),
O7ϪPd1ϪN1 175.47(13), O10ϪPd2ϪO4 166.48(12).
two C5Me5 signals which implicates that only one dia-
stereoisomer is formed. The same bridging occurs in the
trinuclear palladium complex 5 which was obtained from
PdII acetate and 2-phenyl-5(4H)-oxazolone. In 5 one acetate
[8]
bridge of Pd3ac6 is substituted by a C-o,N-bridging 2-
phenyloxazolone.
The molecular structure of 5 is very similar to that of
[8]
Pd3ac6 with the exception that the Pd2ϪO12 distance
˚
[2.087(3) A] is longer than the other PdϪO bonds (ca. 2.01
˚
A). This can be attributed to the trans influence of the
strong C donor.
2. Addition of the 2-Phenyloxazolone Anion to Unsaturated
Hydrocarbons of Cationic Complexes
The addition of organic and organometallic nucleophiles
to π-coordinated hydrocarbons is a very well studied and
important reaction[9]. The addition of the 2-phenyl-5(4H)-
oxazolone anion to the cyclopentadienyl and the cyclohep-
tatrienyl ligand afforded the complexes 6Ϫ11.
In 6 and 7 two stereogenic centers are formed and the
two diastereoisomers (6: 1:1.2; 7: 1:1.8) can be detected in
1
their H- and 13C-NMR spectra. For almost all atoms two
sets of signals are observed. Interestingly, for 8 one dia- trum only some weak signals can be assigned to the second
stereoisomer is formed in high excess. In the 1H-NMR spec- isomer; exo addition is proven for 6 and 7 by the signals of
486
Eur. J. Inorg. Chem. 1998, 485Ϫ493

Metal Complexes of Biologically Important Ligands, CII
FULL PAPER
the CHϪCH2 group and for 9 and 10 by X-ray structure de-
termination.
Figure 3. Molecular structure of 9[a] in the crystal
[a]
˚
Selected bond lengths [A] and angles [°]: CrϪC1 1.853(4),
CrϪC2 1.849(4), CrϪC3 1.858(4), C1ϪO1 1.151(4), CrϪC5
2.196(4), CrϪC6 2.201(4), CrϪC7 2.340(4), C8ϪC11 1.549(5),
C13ϪN1 1.266(4), C13ϪC14 1.472(4); O5ϪC13ϪN1 117.5(3),
C14ϪC13ϪN1 126.3(3), O4ϪC12ϪO5 122.0(3).
Figure 4. Molecular structure of 10[a] in the crystal
1
stereogenic centers) were observed in their H-NMR spec-
tra (from the methoxy signals). Saponification of 15Ϫ18
could be accomplished to give the free acids 19Ϫ22.
[a]
˚
Selected bond lengths [A] and angles [°]:CrϪC1 1.840(9), CrϪC2
1.867(8), CrϪC3 1.840(8), C1ϪO1 1.164(8), CrϪC6 2.175(7),
CrϪC5 2.228(7), CrϪC4 2.352(7), C10ϪC11 1.560(9), C14ϪN
1.255(8), C15ϪC14 1.459(10); O5ϪC14ϪN 116.3(7), C15ϪC14ϪN
129.8(7), O4ϪC13ϪO5 121.6(7).
3. Formation of Dipeptide Derivatives from 1, 2 and 6
The nucleophilic addition of α-amino acid esters[10] to 1,
2 and 6 gave the dipeptide derivatives 12Ϫ18.
Compounds 19Ϫ22 were used as dianionic chelate li-
gands (deprotonation of the amide and carboxylic group)
The shift of the carbonyl IR absorption to lower wave- towards (Ph3P)2PtCl2 to afford the heterobimetallic com-
numbers (ca. 1590 cmϪ1) in 12Ϫ14 is characteristic for co- plexes 23Ϫ25. Recently, several examples for complexes
ordination of the CO function[11]. The two stereogenic cen- with dianionic N-acyl-α-amino carboxylates have been re-
ters of 15 give rise to two diastereoisomers (1:1.2), whereas ported[12] which can be considered as simple models for
four diastereoisomers of 16Ϫ18 (1:1:1.2:1.2) (from three O,N coordination of peptides.
Eur. J. Inorg. Chem. 1998, 485Ϫ493
487

W. Bauer, M. Prem, K. Polborn, K. Sünkel, W. Steglich, W. Beck
FULL PAPER
2: 204 mg (0.81 mmol) of 4-benzyl-2-phenyl-5(4H)-oxazolone
was used. Yellow powder. Ϫ IR (KBr): ν˜ ϭ 1845 cmϪ1 s (CϭO),
Two diastereoisomers of 23 (as for 15) and four isomers
of 24 and 25 (as for 16 and 17) were observed in the 31P-
NMR spectra.
1
1623 s (CϭN); (PE): ν˜ ϭ 292 cmϪ1 s (MϪCl). Ϫ H NMR (270
MHz, CDCl3): δ ϭ 1.79/1.83 [each s, 15H 20:1, C5(CH3)5], 3.06
2
3
2
(dd, J ϭ 15.0 Hz, J ϭ 10.7 Hz, 1 H, CHHЈ), 3.64 (dd, J ϭ 15.0
Hz, 3J ϭ 4.6 Hz, 1 H, CHHЈ), 4.60 (dd, J ϭ 4.6 Hz, 3J ϭ 10.6
3
Hz, 1 H, CHCH2Ph), 7.07 (m, 1 H, C6H4), 7.32 (m, 6 H, C6H4 and
C6H5), 7.55 (m, 1 H, C6H4), 7.84 (m, 1 H, C6H4). Ϫ 13C NMR
(100.5 MHz, CDCl3): δ ϭ 9.30/9.40 [C5(CH3)5], 36.80 (CH2Ph),
62.20 (CHCH2Ph), 88.40/86.20 [C5(CH3)5], 122.30, 127.40, 127.50,
128.50, 128.70, 129.40, 133.90, 134.70, 135.60 (C6H4 and C6H5),
166.50 (OCϭN), 172.40 (IrϪC), 177.90 (CϭO). Ϫ C26H27ClIrNO2
ϫ 0.5 CH2Cl2 (655.6): calcd. C 48.53, H 4.27, N 2.13; found C
48.06, H 4.30, N 2.07.
3: 176 mg (0.81 mmol) of 4-(2Ј-butyl)-2-phenyl-5(4H)-oxazolone
was used. Yellow powder. Ϫ IR (KBr): ν˜ ϭ 1844 cmϪ1 s (CϭO),
1
1626 s (CϭN); (PE): ν˜ ϭ 283 cmϪ1 s (MϪCl). Ϫ H NMR (270
MHz, CDCl3): δ ϭ 1.28 (m, 2 H, CH2), 0.83Ϫ1.09 (m, 6 H, 2 ϫ
CH3), 1.74/1.75 [each s, 15H 1.2:1, C5(CH3)5], 4.29 [m, 1 H,
CH(C4H9)], 7.07 (m, 1 H, C6H4), 7.28 (m, 1 H, C6H4), 7.52 (m, 1
H, C6H4), 7.81 (m, 1 H, C6H4). Ϫ 13C NMR (100.5 MHz, CDCl3):
δ ϭ 9.40/9.80 [C5(CH3)5], 11.80 (CH2CH3), 14.80 (CHCH3), 25.80
(CH2CH3), 36.60 (CHCH3), 67.80 (CHC4H9), 88.40 [C5(CH3)5],
122.40, 127.30, 131.50, 133.90, 135.90 (C6H4), 166.90 (OCϭN),
173.20 (IrϪC), 178.30 (CϭO). Ϫ C23H29ClIrNO2 (655.6): calcd. C
47.70, H 5.05, N 2.42; found C 48.56, H 5.53, N 2.89.
Conclusions
The reaction of oxazolones with organometallic com-
plexes leads to a versatile chemistry and the reaction of 1,
2 and 6 with α-amino acid esters (or peptide esters) provides
a method for the labelling of peptides at the amino ter-
minus.
4: To a mixture of 51 mg (0.32 mmol) of 2-phenyl-5(4H)-oxazo-
lone and 26 mg (0.32 mmol) of NaOAc in 5 ml of CH2Cl2 a deep
red solution of 247 mg (0.31 mmol) of [Cp*IrCl2]2 in 5 ml of the
same solvent was added. After stirring for 5 h the light red mixture
was filtered to remove NaCl, and concentrated in vacuo to about
2 ml. The yellow product was precipitated with 15 ml of Et2O,
washed twice with 3 ml Et2O and dried in vacuo at 60°C for 5 h.
Crystals were obtained from a CH2Cl2/pentane mixture. Ϫ IR
(KBr): ν˜ ϭ 1792 cmϪ1 s (CϭO), 1608 w (CϭN); (PE): ν˜ ϭ 262
cmϪ1 s, 288 s, 299 m (MϪCl). Ϫ 1H NMR (270 MHz, CDCl3):
δ ϭ 1.39 [s, 15 H, C5(CH3)5], 1.58 [s, 15 H, C5(CH3)5], 6.12 (s, 1
Support by the Deutsche Forschungsgemeinschaft, the Fonds der
Chemischen Industrie and the Wacker Chemie, München, is grate-
fully acknowledged.
Experimental Section
All reactions were carried out in dry solvents under nitrogen. Ϫ
NMR: Jeol GSX 270 or Jeol EX 400, using the solvent as internal
standard. Ϫ IR: Nicolet 520 FT-IR. Ϫ The starting materials were
[13]
prepared according to literature procedures ([Cp*IrCl2]2
,
,
[16]
[(C6H7)Fe(CO)3]BF4[14], [(C7H7)Cr(CO)3]BF4[15], (COD)PtCl2
2-phenyl-5(4H)-oxazolones[17]). PdII acetate was purchased from
Aldrich and purified by dissolving it in hot benzene, filtering and
evaporating off the solvent. Glacial acetic acid was refluxed over
KMnO4 for several hours and distilled prior to use. The α-amino
acid ester hydrochlorides were purchased from Merck or Fluka. Ϫ
PE ϭ polyethylene.
3
H, CHIr), 7.27Ϫ7.56 (m, 3 H, 3,4,5-C6H5), 8.61 (d, J ϭ 7.9 Hz,
2 H, 2,6-C6H5). Ϫ 13C NMR (100.5 MHz, CD2Cl2): δ ϭ 8.57
[C5(CH3)5], 8.63 [C5(CH3)5], 67.79 (CHIr), 86.86 [C5(CH3)5], 87.12
[C5(CH3)5] 125.91, 128.56, 129.83, 132.49 (C6H5), 161.15 (OCϭN),
179.00 (CϭO). Ϫ C29H36Cl3Ir2NO2 (921.4): calcd. C 37.76, H 3.90,
N 1.51; found C 37.41, H 3.89, N 1.55.
General Procedure for the Preparation of 1Ϫ3: To a mixture of
the oxazolone and 66 mg (0.81 mmol) of NaOAc in 5 ml of CH2Cl2
a deep red solution of 319 mg (0.4 mmol) of [Cp*IrCl2]2 in 5 ml
of the same solvent was added. After stirring overnight, the light-
red mixture was filtered to remove NaCl, and the solvent was re-
moved in vacuo. The yellow product was washed twice with 3 ml
of Et2O and dried in vacuo at 60°C for 5 h.
5: A brown suspension of 123 mg (0.55 mmol) of palladium(II)
acetate and 88 mg (0.55 mmol) of 2-phenyl-5(4H)-oxazolone in 2
ml of glacial acetic acid was heated to 95°C for 30 min whereby
the product began to precipitate. After cooling, the mixture was
centrifuged. The dark brown residue was washed with 1ml of gla-
cial acetic acid and twice with 2 ml of water. After drying in vacuo
at 50°C for 3 h, the dark brown product was dissolved in 5 ml of
1: 142 mg (0.81 mmol) of 4-methyl-2-phenyl-5(4H)-oxazolone trichloromethane, filtered and added to 30 ml of n-hexane. The
was used. Yellow powder. Ϫ IR (KBr): ν˜ ϭ 1844 cmϪ1 s (CϭO), orange precipitate was centrifuged off, washed with pentane and n-
1
1627 s (CϭN); (PE): ν˜ ϭ 288 cmϪ1 s (MϪCl). Ϫ H NMR (400 hexane and dried in vacuo at 50°C for 8 h. Slow concentration of
MHz, CDCL3): δ ϭ 1.66 (d, 3J ϭ 7.5 Hz, 3 H, CH3), 1.76/1.82 a solution in CH2Cl2/hexane (1:10) gave orange prisms, suitable for
3
[each s, 15H 5:1, C5(CH3)5], 4.43 (q, J ϭ 7.5 Hz, 1 H, CHCH3), X-ray analysis. Ϫ IR (KBr): ν˜ ϭ 1807 cmϪ1 s (CϭO), 1608 s, 1592
7.04 (m, 1 H, C6H4), 7.27 (m, 1 H, C6H4), 7.53 (m, 1 H, C6H4), s, 1569 s (antisym. COO), 1421 s (sym. COO). Ϫ 1H NMR (400
7.82 (m, 1 H, C6H4). Ϫ 13C NMR (100.5 MHz, CDCl3): δ ϭ 9.44/ MHz, CDCl3): δ ϭ 1.48 (s, 3 H, CH3COO), 1.94 (s, 3 H,
9.94 [C5(CH3)5], 15.97 (CH3), 58.86 (CHCH3), 88.53/89.27 CH3COO), 1.97 (s, 3 H, CH3COO), 2.00 (s, 3 H, CH3COO), 2.05
[C5(CH3)5], 122.53, 127.63, 128.84, 134.05, 135.85 (C6H4), 166.37
(OCϭN), 174.91 (IrϪC), 177.94 (CϭO).
C20H23ClIrNO2 7.79 (A, 1 H, 4-C6H5), 9.15 (CCЈ, 2 H, 2,6-C6H5). Ϫ 13C NMR
(536.7): calcd. C 44.71, H 4.28, N 2.60; found C 44.46, H 4.75, (100.5 MHz, CDCl3): δ ϭ 22.19 (CH3COO), 22.76 (CH3COO),
(s, 3 H, CH3COO), 5.41 (s, 1 H, CHPd), 7.70 (BBЈ, 2 H, 3,5-C6H5),
Ϫ
N 2.41.
23.00 (CH3COO), 23.33 (CH3COO), 23.39 (CH3COO), 38.99
488
Eur. J. Inorg. Chem. 1998, 485Ϫ493

Metal Complexes of Biologically Important Ligands, CII
FULL PAPER
(CHPd), 123.78, 129.15, 129.96, 135.00 (C6H5), 165.50 (OCϭN), THF was cooled to 0°C. A solution of triethylamine in 5 ml of
172.93 (CϭO), 185.41 (CH3COO), 185.47 (CH3COO), 186.86 THF was slowly added. After stirring overnight, the red solution
(CH3COO), 188.13 (CH3COO), 188.59 (CH3COO).
Ϫ
was concentrated to about 4 ml, triethylammonium chloride was
C19H21NO12Pd3 (774.6): calcd. C 29.46, H 2.73, N 1.81; found C precipitated with 40 ml of Et2O and filtered off. The filtrate was
29.38, H 3.18, N 1.75.
taken to dryness and the residue was dissolved in 30 ml of Et2O.
This solution was filtered through Celite and the solvent was re-
moved in vacuo. The residue was dissolved in 1 ml of CH2Cl2 and
added to excess pentane to give the product as orange solid which
was washed twice with pentane and dried in vacuo at 50°C for
several hours.
General Procedure for the Preparation of 6 and 7: A stirred mix-
ture of 150 mg (0.49 mmol) of [(C6H7)Fe(CO)3]BF4 and the appro-
priate oxazolone in 15 ml of CH2Cl2 was cooled (see below). A
solution of 64.8 µl (0.47 mmol) of triethylamine in 5 ml of CH2Cl2
was slowly added. After 30 min of stirring at low temp., the yellow
solution was allowed to warm up to room temp. and stirred for
another 2 h. After concentrating to about 4 ml, triethylammonium
chloride was precipitated with 40 ml of pentane and filtered off.
The filtrate was concentrated and the residue was dissolved in 30
ml of pentane. This yellow solution was filtered through Celite and
concentrated in vacuo to about 4 ml. Cooling to Ϫ78°C for 3 min
gave a colourless precipitate which was filtered off. Removal of the
solvent from the filtrate in vacuo gave the yellow, oily product
which was dried in vacuo at room temp. for a few days.
8: 98 mg (0.31 mmol) of [(C7H7)Cr(CO)3]BF4, 117 mg (0.31
mmol) of 6 and 43.5 µl (0.31 mmol) of NEt3 were used. The reac-
tion was carried out in CH2Cl2 instead of THF. The CH2Cl2/pen-
tane mixture had to be slowly concentrated to give the product. Ϫ
IR (KBr): ν˜ ϭ 2045 cmϪ1 s (FeϪCO), 1979 s br. (FeϪCO,
CrϪCO), 1924 s, 1884 s, 1878s, 1870 s (CrϪCO), 1807 s (CϭO),
1
1653 s (CϭN). Ϫ H NMR (270 MHz, CDCl3): δ ϭ 1.42 (ddd, 1
H, 2J6endo ϭ 14.9 Hz, 3J1 ϭ 3.6 Hz, 3J5 ϭ 2.5 Hz, 6exo-C6H7), 1.87
2
3
3
(2.00) (ddd, 1 H, J6exo ϭ 14.9 Hz, J1 ϭ 10.8 Hz, J5 ϭ 4.2 Hz,
3
3
6: 75 mg (0.47 mmol) of 2-phenyl-5(4H)-oxazolone was used.
The addition of NEt3 was carried out at Ϫ15°C. Ϫ IR (film NaCl):
ν˜ ϭ 2045 cmϪ1 s (FeϪCO), 1964 s br. (FeϪCO), 1824 s (CϭO),
6endo-C6H7), 2.59 (ddd, 1 H, J6endo ϭ 10.6 Hz, J6exo ϭ 3.5 Hz,
3J2 ϭ 3.5 Hz, 1-C6H7), 2.68 (ddd, 1 H, 3J3 ϭ 5.1 Hz, 3J1 ϭ 3.5 Hz,
4J4 ϭ 2.2 Hz, 2-C6H7), 2.94 (3.06) (ddd, 1 H, 3J4 ϭ 7.9 Hz,
1
3
3J6endo ϭ 3.7 Hz, J6exo ϭ 2.2 Hz, 5-C6H7), 3.61 (m, 3 H, 1,2,7-
1653 s (CϭN). Ϫ H NMR (400 MHz, CDCl3): δ ϭ 1.77 (dm, 1
2
2
H, J6endo ϭ 15.3 Hz, 6exo-C6H7)/1.61 (ddd, 1 H, J6endo ϭ 15.0
C7H7), 4.82 (5.00) (m, 2 H, 3,6-C7H7), 5.23 (5.36) (m, 2 H, 3,4-
C6H7), 5.85 (m, 1 H, 4-C7H7), 5.98 (m, 1 H, 5-C7H7), 7.50 (BBЈ, 2
H, 3,5-C6H5), 7.60 (A, 1 H, 4-C6H5), 7.86 (7.78) (CCЈ, 2 H, 2,6-
C6H5). Diastereoisomeric ratio about 13:1. Ϫ 13C NMR (100.4
MHz, CDCl3): δ ϭ 26.70 (6-C6H7), 41.12 (1-C7H7), 44.44 (1-C6H7),
56.51, 58.62 (2,5-C6H7), 62.39, 64.27 (2,7-C7H7), 83.34
(NCRRЈCOO), 85.56, 86.18 (3,4-C6H7), 97.50, 98.03, (4,5-C7H7),
102.04, 102.29 (3,6-C7H7), 125.60, 128.25, 129.21, 133.23 (C6H5),
160.30 [OC(Ph)N], 176.91 (CRRЈCOO), 211.52 (FeϪCO). Ϫ
C28H19CrFeNO8 (605.3): calcd. C 55.56, H 3.16, N 2.31; found C
55.50, H 3.05, N 2.24.
3
3
Hz, J1 ϭ 3.7 Hz, J5 ϭ 2.6 Hz, 6exo-C6H7), 2.14/2.06 (each ddd,
1 H/1 H, J6exo ϭ 15.1 Hz, 3J1 ϭ 11.1 Hz, 3J5 ϭ 4.0 Hz, 6endo-
2
C6H7), 2.74 (m, 1 H ϩ 1 H, 1-C6H7), 2.92 (ddd, 1 H, 3J3 ϭ 6.3 Hz,
3J1 ϭ 3.3 Hz, J4 ϭ 1.4 Hz, 2-C6H7)/3.06, 3.06 [m, 1 H ϩ 1 H (ϩ
4
3
1 H, 2-C6H7), 5-C6H7], 4.20/4.24 [each d, 1 H/1 H, J1 ϭ 6.0 Hz,
NCH(C6H7)COO], 5.32 (ddd, 1 H, 3J2 ϭ 6.1 Hz, 3J4 ϭ 4.4 Hz,
4J5 ϭ 1.6 Hz, 3-C6H7)/5.39, 5.39 [m, 1 H ϩ 1 H (ϩ 1 H, 3-C6H7),
4-C6H7], 7.43Ϫ7.60 (ABBЈ, 3 H ϩ 3 H, 3,4,5-C6H5), 7.96Ϫ8.00
(CCЈ, 2 H ϩ 2 H, 2,6-C6H5). Ϫ 13C NMR (100.5 MHz, CDCl3):
δ ϭ 27.77/26.50 (6-C6H7), 40.25/40.98 (1-C6H7), 59.38/59.39, 59.26/
58.83 (2,5-C6H7), 70.03/69.99 [CNCH(C6H7)COO], 86.06/86.51,
85.83/85.48 (3,4-C6H7), 125.95, 128.20, 129.14, 133.16, 126.11,
128.22, 129.12, 133.14 (C6H5), 162.07/161.95 [CNCH(C6H7)COO],
176.90/177.29 [CNCH(C6H7)COO], 211.69 (FeϪCO). Dia-
stereomeric ratio 1.0:1.15. Ϫ C18H13FeNO5 (379.2): calcd. C 57.02,
H 3.46, N 3.69; found C 57.38, H 4.14, N 3.48.
9: 250 mg (0.80 mmol) of [(C7H7)Cr(CO)3]BF4, 125 mg (0.78
mmol) of 2-phenyl-5(4H)-oxazolone and 108.1 µl (0.78 mmol) of
NEt3 were used. The product could not be obtained analytically
pure. For X-ray analysis suitable crystals were grown in an CH2Cl2
pentane mixture. Ϫ IR (KBr): ν˜ ϭ 1981 cmϪ1 s, 1915 s, 1883 s
1
(CrϪCO), 1820 s (CϭO), 1651 s (CϭN). Ϫ H NMR (400 MHz,
7: 86 mg (0.49 mmol) of 4-methyl-2-phenyl-5(4H)-oxazolone was
used. The addition of NEt3 was carried out at 0°C. Ϫ IR (film
NaCl): ν˜ ϭ 2048 cmϪ1 s (FeϪCO), 1969 s br. (FeϪCO), 1816 s
CDCl3): δ ϭ 3.12 [d, 1 H, NCH(C7H7)CO], 3.55 (m, 1 H, 2-C7H7),
3.65 (m, 1 H, 7-C7H7), 3.75 (m, 1 H, 1-C7H7), 4.90 (m, 1 H, 3-
C7H7), 5.05 (m, 1 H, 6-C7H7), 6.00 (m, 1 H, 4-C7H7), 6.05 (m, 1
H, 5-C7H7), 7.40Ϫ7.65 (ABBЈ, 3 H, 3,4,5-C6H5), 7.88 (CCЈ, 2 H,
2,6-C6H5). Ϫ 13C-NMR (100.4 MHz, CDCl3): δ ϭ 40.14 (1-C7H7),
61.79, 62.15 (2,7-C7H7), 70.96 [NCH(C7H7)CO], 97.99, 98.25 (4,5-
C7H7), 100.90, 101.17 (3,6-C7H7), 125.67, 128.17, 129.12, 133.29
(C6H5), 162.42 [OC(C6H5)N], 175.00 [NCH(C7H7)COO].
1
(CϭO), 1658 s (CϭN). Ϫ H NMR (400 MHz, CDCl3): δ ϭ 1.41/
1.43 [each s, 3H/3 H, NCCH3(C6H7)COO], 1.78 (dm, 1 H, 2J6endo ϭ
15.3 Hz, 6exo-C6H7)/1.70 (dm, 1 H, 2J6endo ϭ 15.1 Hz, 6exo-C6H7),
2.04/1.99 (each ddd, 1 H/1 H, J6exo ϭ 15.2 Hz, 3J1 ϭ 11.0 Hz,
2
3J5 ϭ 4.3 Hz, 6endo-C6H7), 2.58 (m, 1 H/1 H, 1-C6H7), 2.72/2.99
3
3
4
(each ddd, 1 H/1 H, J3 ϭ 6.2 Hz, J1 ϭ 3.2 Hz, J4 ϭ 1.3 Hz, 2-
C6H7), 3.04 (m, 1 H/1 H, 5-C6H7), 5.21/5.31 (each ddd, 1 H/1 H,
10: 500 mg (1.59 mmol) of [(C7H7)Cr(CO)3]BF4, 279 mg (1.59
mmol) of 4-methyl-2-phenyl-5(4H)-oxazolone and 222 µl (1.59
mmol) of NEt3 were used. Ϫ IR (KBr): ν˜ ϭ 1980 cmϪ1 s, 1915 s,
3
4
3J2 ϭ 5.6 Hz, J4 ϭ 4.3 Hz, J5 ϭ 1.4 Hz, 3-C6H7), 5.30 (m, 1 H,
4-C6H7)/5.35 (dd, 1 H, 3J3 ϭ 5.0 Hz, 3J5 ϭ 6.0 Hz, 4-C6H7),
7.42Ϫ7.60 (ABBЈ, 3 H ϩ 3 H, 3,4,5-C6H5), 7.98Ϫ7.99 (CCЈ, 2 H
ϩ 2 H, 2,6-C6H5). Ϫ 13C NMR (100.5 MHz, CDCl3): δ ϭ 22.44/
22.56 (CH3), 26.29/25.43 (6-C6H7), 46.33/45.45 (1-C6H7), 59.16/
59.25, 57.63/58.13 (2,5-C6H7), 72.85/72.80 [CNCCH3(C6H7)COO],
86.01/86.32, 85.59/85.38 (3,4-C6H7), 126.21, 133.06, 126.01, 128.21,
129.12, 133.02 (C6H5), 160.27/159.94 [CNCCH3(C6H7)COO],
180.48/179.87 [CNCCH3(C6H7)COO], 211.72 (FeϪCO). Dia-
stereomeric ratio 1.0:1.8. Ϫ C19H15FeNO5 (393.2): calcd. C 58.04,
H 3.85, N 3.56; found C 57.50, H 3.79, N 2.84.
1
1887 s (Cr-CO), 1806 s (CϭO), 1651 s (CϭN). Ϫ H NMR (400
MHz, CDCl3): δ ϭ 1.24 [s, 3 H, NCCH3(C7H7)CO], 3.43 (2-C7H7),
3.67 (7-C7H7), 3.69 (1-C7H7), 4.73 (3-C7H7), 5.01 (6-C7H7), 5.84
3
(4-C7H7), 6.04 (5-C7H7) (each pseudo-t, J ഠ 8 Hz), 7.47 (BBЈ, 2
H, 3,5-C6H5), 7.57 (A, 1 H, 4-C6H5), 7.88 (CCЈ, 2 H, 2,6-C6H5).
Ϫ
13C-NMR (100.4 MHz, CDCl3): δ ϭ 18.63 (CH3), 45.93 (1-
C7H7), 62.79, 63.62 (2,7-C7H7), 76.19 [NC(CH3)(C7H7)CO], 97.34,
98.01 (4,5-C7H7), 102.33, 102.47 (3,6-C7H7), 125.68, 128.24,
129.15,
133.14
(C6H5),
160.00
[OC(C6H5)N],
178.69
General Procedure for the Preparation of 8Ϫ11: A stirred mixture
[NC(CH3)(C7H7)COO]. Ϫ C20H15CrNO5 (401.3): calcd. C 59.86,
of [(C7H7)Cr(CO)3]BF4 and the appropriate oxazolone in 15 ml of H 3.77, N 3.49; found C 59.42, H 3.96, N 3.29.
Eur. J. Inorg. Chem. 1998, 485Ϫ493
489

W. Bauer, M. Prem, K. Polborn, K. Sünkel, W. Steglich, W. Beck
11: 200 mg (0.64 mmol) of [(C7H7)Cr(CO)3]BF4, 50 mg (0.31 used and stirred for 7 d. Ϫ IR (KBr): ν˜ ϭ 3283 cmϪ1 m br. (NϪH),
FULL PAPER
mmol) of 2-phenyl-5(4H)-oxazolone and 86.5 µl (0.62 mmol) of
2047 s (FeϪCO), 1975 s br. (FeϪCO), 1755 s (COOCH3), 1637 s/
NEt3 were used. Ϫ IR (KBr): ν˜ ϭ 1980 cmϪ1 s, 1915 s, 1887 s
1661 s (CONH-I), 1531 s/1550 s (CONH-II). Ϫ 1H NMR (400
1
2
(CrϪCO), 1807 s (CϭO), 1651 s (CϭN). Ϫ H NMR (400 MHz, MHz, CDCl3): δ ϭ 1.52/1.48 (each dm, 1 H/1 H, J6endo ϭ 14.5
2
CDCl3): δ ϭ 3.32 (2-C7H7), 3.49 (7-C7H7), 3.69 (1-C7H7), 4.77 (3-
Hz, 6exo-C6H7), 1.97/2.04 (each ddd, 1 H/1 H, J6exo ϭ 15.0 Hz,
C7H7), 4.85 (6-C7H7), 5.85 (4-C7H7), 5.96 (5-C7H7) (each pseudo- 3J1 ϭ 11.0 Hz, J5 ϭ 5.0 Hz, 6endo-C6H7), 2.68/2.73 (each dddd,
3
3
3
3
3
3
t, J ഠ 8 Hz), 7.49 (BBЈ, 2 H, 3,5-C6H5), 7.58 (A, 1 H, 4-C6H5), 1 H/1 H, J6endo ϭ 10.6 Hz, J7 ϭ 6.9 Hz, J2 ϭ J6exo ϭ 3.5 Hz,
7.77 (CCЈ, 2 H, 2,6-C6H5). Ϫ 13C NMR (100.4 MHz, CDCl3): δ ϭ 1-C6H7), 3.04 (m, 2 H/2 H, 2,5-C6H7), 3.72 (s, 1 H/1 H, OCH3),
3
40.32 (1-C7H7), 61.46, 63.30 (2,7-C7H7), 85.49 [NC(C7H7)2CO],
3.92/3.97 (each t, 1 H/1 H, JCHHЈ ϭ 5.2, CONHCH2COOCH3),
97.57, 98.05 (4,5-C7H7), 101.93, 102.42 (3,6-C7H7), 125.22, 128.19, 4.00, 4.05 (each dd, 1 H, 1 H, 2J ϭ 20.9 Hz, JNH ϭ 5.4 Hz,
3
2
129.12,
133.34
(C6H5),
160.45
[OC(C6H5)N],
175.08 NHCHHЈCOOCH3), 4.06, 4.16 (each dd, 1 H, 1 H, J ϭ 27.0 Hz,
[NC(C7H7)2COO]. Ϫ C29H19Cr2NO8 (613.5): calcd. C 56.78, H 3JNH ϭ 5.4 Hz, NHCHHЈCOOCH3) 4.45/4.51 [each dd, 1 H/1 H,
3.12, N 2.28; found C 56.03, H 3.45, N 2.19.
3JNH ϭ 8.4 Hz, 3J1 ϭ 6.9 Hz, CH(C6H7)CONH] 5.32 (m, 2 H, 3,4-
3
3
C6H7), 5.36 (dd, 1 H, J2 ϭ J4 ϭ 4.8 Hz, 3-C6H7), 5.41 (dd, 1 H,
General Procedure for the Preparation of 12Ϫ14: To a mixture of
1 or 2 respectivly, α-amino acid ester hydrochloride and about 2
mg of DMAP in 10 ml of CH2Cl2 69.6 µl (0.5 mmol) of NEt3 was
added. After stirring for about 20 h, the solvent was removed in
vacuo. The residue was washed twice with 5 ml of water and dried
in vacuo at 60°C for 5 h.
3
3
3J3 ϭ J5 ϭ 4.7 Hz, 4-C6H7), 6.82/6.90 (each d, 1 H/1 H, JCH
ϭ
5.2 Hz, CHNHCOPh), 7.40Ϫ7.53 (ABBЈ, 3 H/3 H, 3,4,5-C6H5),
7.76Ϫ7.82 (CCЈ, 2 H/2 H, 2,6-C6H5). Ϫ 13C NMR (100.5 MHz,
CDCl3): δ ϭ 26.93/27.98 (6-C6H7), 40.47/41.37 (1-C6H7), 57.86/
58.43, 59.27/61.17 (2,5-C6H7), 59.79 (NHCH2COOCH3),
85.51/85.19, 85.99/86.27 (3,4-C6H7), 128.96, 132.27, 134.02, 127.39,
129.02, 132.37, 133.81 (C6H5), 167.72, 171.36, 167.74, 170.15,
171.31 (COOCH3, PhCONH, CONH), 211.69 (FeϪCO). Dia-
stereomeric ratio 1.0:1.15. Ϫ C21H20FeN2O7 (468.2): calcd. C
53.87, H 4.31, N 5.98; found C 54.22, H 4.74, N 5.81.
12: 268 mg (0.5 mmol) of 1 and 70 mg (0.5 mmol) of -alanine
methyl ester hydrochloride were used. Yellow powder. Ϫ IR (KBr):
ν ϭ 1745 cmϪ1 w (COOCH3), 1628 m (free CϭO), 1592 m (coord.
˜
CϭO); (PE): ν ϭ 286 cmϪ1 w (MϪCl). Ϫ 1H NMR (270 MHz,
˜
CDCl3): δ ϭ 1.20Ϫ1.80 [m, 21 H, C5(CH3)5 and 2 ϫ CH3], 3.75
(m, 3 H, COOCH3), 4.49 [m, 1 H, NHCH(CH3)COOCH3], 4.68
[m, 1 H, NHCH(CH3)CONH] 6.95 (m, 1 H, C6H4), 7.27 (m, 1 H,
16: 100 mg (0.264 mmol) of 6, 58 mg (0.269 mmol) of phenylala-
nine methyl ester hydrochloride and 37.5 µl (0.269 mmol) of NEt3
were used and stirred for 3 d. Four stereoisomers. Ϫ IR (KBr): ν˜ ϭ
3396 cmϪ1 m br., 3286 s br. (NϪH), 2045 s (FeϪCO), 1967 s br.
(FeϪCO), 1747 s (COOCH3), 1636 s (CONH-I), 1534 s (CONH-
II). Ϫ 1H NMR (270 MHz, CDCl3): δ ϭ 1.39 (m, 1 H, 6exo-C6H7),
1.95 (m, 1 H, 6endo-C6H7), 2.59 (m, 1 H, 1-C6H7), 2.85Ϫ3.22 (m,
4 H, 2,5-C6H7, PhCH2), 3.69, 3.71, 3.72, 3.73 (4 s, 3 H, OCH3),
C6H4), 7.42 (m,
1 H, C6H4), 7.75 (m, 1 H, C6H4). Ϫ
C24H32ClIrN2O4 (639.7): calcd. C 45.02, H 5.00, N 4.37; found C
44.95, H 5.08, N 4.63.
13: 268 mg (0.5 mmol) of 1 and 70 mg (0.5 mmol) of glycine
ethyl ester hydrochloride were used. Yellow powder. Ϫ IR (KBr):
ν˜ ϭ 1752 cmϪ1 s (COOEt), 1655 m (free CϭO), 1593 m (coord.
CϭO); (PE): ν˜ ϭ 283 cmϪ1 w (MϪCl). Ϫ 1H NMR (270 MHz,
CDCl3): δ ϭ 1.24 (m, 3 H, COOCH2CH3), 1.48 [m, 3 H,
NHCH(CH3)CONH], 1.68 [m, 15 H, C5(CH3)5], 3.80 (m, 1 H,
NHCHHЈCOOEt), 3.95 (m, 1 H, NHCHHЈCOOEt), 4.14 (m, 2 H,
COOCH2CH3), 4.64 [m, 1 H, NHCH(CH3)CONH], 6.92 (m, 1 H,
C6H4), 7.26 (m, 1 H, C6H4), 7.52 (m, 1 H, C6H4), 7.75 (m, 1 H,
C6H4). Ϫ C24H32ClIrN2O4 (639.7): calcd. C 45.02, H 5.00, N 4.37;
found C 44.14, H 5.02, N 4.67.
4.29Ϫ4.55 (m,
1
H, PhCONHCH), 4.85 [m,
1
H,
CONHCH(CH2Ph)], 5.32 (m, 2 H, 3,4-C6H7), 6.50 (m, 2 H, 2 NH),
7.02Ϫ7.19 (m, 5 H, CH2C6H5), 7.42Ϫ7.55 (m, 3 H, 3,4,5-C6H5),
7.72Ϫ7.79 (m, 2 H, 2,6-C6H5). Ϫ C28H26FeN2O7 (558.4): calcd. C
60.23, H 4.69, N 5.02; found C 60.59, H 5.17, N 5.15.
17: 100 mg (0.264 mmol) of 6, 54 mg (0.270 mmol) of methionine
methyl ester hydrochloride and 37.6 µl (0.270 mmol) of NEt3 were
used and stirred for 7 d. Four stereoisomers. Ϫ IR (KBr): ν˜ ϭ 3440
cmϪ1 s br., 3290 s br. (NϪH), 2044 s (FeϪCO), 1970 s br.
(FeϪCO), 1745 s (COOCH3), 1636 s (CONH-I), 1535 s (CONH-
II). Ϫ 1H NMR (270 MHz, CDCl3): δ ϭ 1.46 (m, 1 H, 6exo-C6H7),
1.88Ϫ2.20 (m, ca. 3 H, 6endo-C6H7, CH2), 1.99, 2.01, 2.04, 2.05 (4
s, 3 H, SCH3), 2.48 (m, 2 H, CH2), 2.70 (m, 1 H, 1-C6H7), 3.03 (m,
2 H, 2,5-C6H7), 3.68, 3.69, 3.75, 3.76 (4 s, 3 H, OCH3), 4.40Ϫ4.69
[m, 2 H, PhCONHCH, CONHCH(R)], 5.36 (m, 2 H, 3,4-C6H7),
6.67Ϫ7.08 (m, 2 H, 2 NH), 7.39Ϫ7.56 (m, 3 H, 3,4,5-C6H5),
7.75Ϫ7.83 (m, 2 H, 2,6-C6H5). Ϫ C24H26FeN2O7S (542.4): calcd.
C 53.15, H 4.83, N 5.16; found C 52.65, H 4.51, N 5.36.
14: 328 mg (0.5 mmol) of 2 and 70 mg (0.5 mmol) of glycine
ethyl ester hydrochloride were used. Yellow powder Ϫ IR (KBr):
ν ϭ 1743 cmϪ1 m (COOEt), 1670 m (free CϭO), 1592 s (coord.
˜
CϭO); (PE): ν ϭ 282 cmϪ1 w (MϪCl). Ϫ 1H NMR (270 MHz,
˜
CDCl3): δ ϭ 1.21 (m, 3 H, COOCH2CH3), 1.65 [m, 15 H,
C5(CH3)5], 3.27 (m, 2 H, NHCH2COOEt), 4.14 (m, 2 H, CO-
OCH2CH3), 4.77 [m, 1 H, NHCH(CH2Ph)CONH], 6.94 (m, 1 H,
C6H4), 7.31 (m, 1 H, C6H4), 7.59 (m, 1 H, C6H4), 7.75 (m, 1 H,
C6H4). Ϫ C30H36ClIrN2O4 (716.3): calcd. C 50.30, H 5.07, N 3.91;
found C 51.05, H 5.23, N 4.55.
18: 100 mg (0.264 mmol) of 6, 57 mg (0.269 mmol) of glutamic
acid dimethyl ester hydrochloride and 37.5 µl (0.269 mmol) of NEt3
were used and stirred for 7 d. The product precipitated from the
concentrated ether solution without adding pentane. Four stereo-
isomers. Ϫ IR (KBr): ν˜ ϭ 3440 cmϪ1 s br., 3287 s br. (NϪH), 2045
s (FeϪCO), 1970 s br. (FeϪCO), 1741 s (COOCH3), 1637 s
(CONH-I), 1535 s (CONH-II). Ϫ 1H NMR (270 MHz, CDCl3):
δ ϭ 1.46 (m, 1 H, 6exo-C6H7), 1.99 (m, 2 H, CH2), 2.18 (m, 1 H,
6endo-C6H7), 2.38 (m, 2 H, CH2), 2.71 (m, 1 H, 1-C6H7), 3.00 (m,
2 H, 2,5-C6H7), 3.60, 3.61, 3.62, 3.63, 3.67, 3.68, 3.73, 3.74 (8 s, 6
General Procedure for the Preparation of 15Ϫ18: Equimolar
amounts of 6, α-amino acid methyl ester hydrochloride and NEt3
were stirred in about 20 ml of CH2Cl2 at room temp. for a few days
(see below). The solvent was removed in vacuo, and the residue
was taken up in Et2O. Insoluble HNEt3BF4 was centrifuged off.
The yellow solution was filtered through Celite, concentrated in
vacuo to about 1 ml and added to excess pentane. The colourless
precipitate was collected, washed once with pentane and dried in
vacuo for a few days.
15: 59 mg (0.155 mmol) of 6, 20 mg (0.159 mmol) of glycine H, 2 OCH3), 4.50 [m, 2 H, PhCONHCH, CONHCH(R)], 5.36 (m,
methyl ester hydrochloride and 22.2 µl (0.159 mmol) of NEt3 were
2 H, 3,4-C6H7), 6.65Ϫ7.17 (m, 2 H, 2 NH), 7.42Ϫ7.56 (m, 3 H,
Eur. J. Inorg. Chem. 1998, 485Ϫ493
490

Metal Complexes of Biologically Important Ligands, CII
FULL PAPER
3,4,5-C6H5), 7.75Ϫ7.84 (m, 2 H, 2,6-C6H5). Ϫ C25H26FeN2O9 temp., filtered through Celite. The solvent was evaporated and the
(554.3): calcd. C 54.17, H 4.73, N 5.05; found C 53.95, H 4.38, residue dried in vacuo for 2 h. After dissolving in 1 ml of CH2Cl2,
N 5.28.
petroleum ether was added to precipitate the colourless product
which was washed with petroleum ether and dried in vacuo at room
temp. for several days.
General Procedure for the Preparation of 19Ϫ22: To a solution
of 15Ϫ18 in 10 ml of ethanol/water (4:1) a slight excess of NaOH
(0.1 ) was slowly added. After stirring for a few hours, an equimo-
lar amount of HCl (0.1 ) was added and after 30 min of further
stirring the solvents were removed under reduced pressure. The
residue was taken up in Et2O/THF (1:1) (19), Et2O/acetone (10:1)
(22), or Et2O (20, 21) and filtered through Celite to remove NaCl.
After concentrating in vacuo, the solution was added to excess pen-
tane to precipitate the colourless product which was collected,
washed once with pentane and dried in vacuo at 50°C for a few
days.
23: 9 mg (0.024 mmol) of (COD)PtCl2, 11 mg (0.024 mmol) of
19, 13 mg (0.05 mmol) of PPh3 and 12 mg (0.052 mmol) of Ag2O
were used. Ϫ IR (KBr): ν˜ ϭ 3410 cmϪ1 s br. (NϪH), 2042 s
(FeϪCO), 1965 s br. (FeϪCO), 1653 s br. (coord. COO, CONH-
I), 1512 s (CONH-II). Ϫ H NMR (270 MHz, CDCl3): δ ϭ 1.55
(m, 1 H, 6exo-C6H7), 1.98 (m, 6endo-C6H7), 2.60 (m, 1 H, 1-C6H7),
1
3.05 (m,
4
H, 2,5-C6H7, NCH2COO), 4.40 [m,
1
H,
NHCH(C6H7)CON], 5.35 (m, 2 H, 3,4-C6H7), 6.99Ϫ7.82 (m, 35
2
1
H, 7 C6H5). Ϫ 31P NMR: δ ϭ 2.97 (d, JP-P ϭ 18.6 Hz, JP-Pt
ϭ
2
1
19: 43 mg (0.092 mmol) of 15, 0.93 ml of 0.1  NaOH and 0.93
3665 Hz, P trans to O), 4.08 (d, JP-P ϭ 23.1 Hz, JP-Pt could not
ml of 0.1  HCl were used. Ϫ IR (KBr): ν ϭ 3407 cmϪ1 m br.,
˜
be determined, P trans to O), 10.36 (d, 2JP-P ϭ 23.1 Hz, 1JP-Pt could
2
3305 s br. (OϪH, NϪH), 2046 s (FeϪCO), 1973 s br. (FeϪCO),
1729 s (COOH), 1637 s (CONH-I), 1535 s (CONH-II). Ϫ 1H NMR
(400 MHz, [D6]acetone): δ ϭ 1.60 (m, 1 H, 6exo-C6H7), ca. 2.00
(m, 6endo-C6H7), 2.80 (m, 1 H, 1-C6H7), 3.27 (m, 2 H, 2,5-C6H7),
3.96 (m, 2 H, CH2), 4.48 (m, 1 H, PhCONHCH), 5.61 (m, 2 H,
3,4-C6H7), 7.42Ϫ7.58 (m, 3 H, 3,4,5-C6H5), 7.88Ϫ8.00 (m, 2 H,
2,6-C6H5), 9.96 (s, 1 H, COOH). Ϫ C20H18FeN2O7 (454.2): calcd.
C 52.89, H 3.99, N 6.17; found C 52.44, H 3.90, N 6.16.
not be determined, P trans to N), 18.61 (d, JP-P ϭ 18.6 Hz,
1JP-Pt ϭ 3921 Hz, P trans to N). Diastereomeric ratio 6:1. Ϫ
C56H46FeN2O7P2Pt ϫ 0.5 CH2Cl2 (1214.3): calcd. C 55.89, H 3.90,
N 2.31; found C 55.16, H 3.90, N 2.32.
24: 16 mg (0.043 mmol) of (COD)PtCl2, 23 mg (0.042 mmol) of
20, 22 mg (0.084 mmol) of PPh3 and 20 mg (0.086 mmol) of Ag2O
were used. Ϫ IR (KBr): ν˜ ϭ 3430 cmϪ1 m br. (NϪH), 2042 s
(FeϪCO), 1967 s br. (FeϪCO), 1653 s br. (coord. COO, CONH-
20: 70 mg (0.125 mmol) of 16, 1.3 ml of 0.1  NaOH and 1.3 ml
of 0.1  HCl were used. Four stereoisomers. Ϫ IR (KBr): ν˜ ϭ 3428
cmϪ1 s br. (OϪH, NϪH), 2045 s (FeϪCO), 1970 s br. (FeϪCO),
1729 s (COOH), 1641 s (CONH-I), 1523 s (CONH-II). Ϫ 1H NMR
(270 MHz, CDCl3): δ ϭ 1.34 (m, 1 H, 6exo-C6H7), 1.91 (m, 1 H,
6endo-C6H7), 2.37Ϫ3.33 (m, 5 H, CH2, 1-C6H7, 2,5-C6H7), 3.63,
4.38 (2 m, 1 H, PhCONHCH), 4.78 [m, 1 H, CONHCH(CH2Ph)],
5.28 (m, 2 H, 3,4-C6H7), 6.72 (m, 1 H, NH), 6.96Ϫ7.60 (m, 9 H,
NH, CH2C6H5, 3,4,5-C6H5), 7.66Ϫ7.86 (m, 2 H, 2,6-C6H5). Ϫ
C27H24FeN2O7 (544.3): calcd. C 59.58 H 4.44, N 5.15; found C
59.59, H 4.61, N 5.19.
1
I), 1509 s (CONH-II). Ϫ H NMR (270 MHz, CDCl3): δ ϭ 1.48
(m, 1 H, 6exo-C6H7), 1.85 (m, 6endo-C6H7), 2.24 (m, 1 H, 1-C6H7),
2.90 (m,
4
H, 2,5-C6H7, CH2Ph), 3.72 [m,
1
H,
NCH(CH2Ph)COO], 4.30 [m, 1 H, NHCH(C6H7)CON], 5.25 (m,
2 H, 3,4-C6H7), 6.78Ϫ7.82 (m, 40 H, 8 C6H5). Ϫ 31P NMR: δ ϭ
2
1
2.85, 2.87, 2.92, 2.98 (each d, JP-P ϭ 18.9 Hz, JP-Pt ϭ 3669 Hz,
2
P trans to O), 18.33, 18.36, 18.38, 18.41 ( each d, JP-P ϭ 18.3
Hz, JP-Pt ϭ 3893 Hz, P trans to N). Diastereomeric ratio about
1
1:1:1.5:1.5. Ϫ C63H52FeN2O7P2Pt ϫ 0.5 CH2Cl2 (1304.5): calcd. C
58.01, H 4.02, N 2.15; found C 57.78, H 4.33, N 2.04.
21: 51 mg (0.094 mmol) of 17, 0.98 ml of 0.1  NaOH and 0.98
25: 13.5 mg (0.036 mmol) of (COD)PtCl2, 19 mg (0.036 mmol)
ml of 0.1  HCl were used. Four stereoisomers. Ϫ IR (KBr): ν ϭ of 21, 18.9 mg (0.072 mmol) of PPh3 and 18 mg (0.078 mmol) of
˜
˜ ϭ 3415 cmϪ1 s br. (NϪH), 2042
3403 cmϪ1 m br., 3300 s br. (OϪH, NϪH), 2047 s (FeϪCO), 1970 Ag2O were used. Ϫ IR (KBr): ν
s br. (FeϪCO), 1723 s (COOH), 1636 s (CONH-I), 1532 s (CONH- s (FeϪCO), 1967 s br. (FeϪCO), 1652 s br. (coord. COO, CONH-
1
1
II). Ϫ H NMR (400 MHz, [D6]acetone): δ ϭ 1.60 (m, 1 H, 6exo-
I), 1512 s (CONH-II). Ϫ H NMR (270 MHz, CDCl3): δ ϭ 1.52
C6H7), ca. 2.00 (m, 6endo-C6H7, CH2, SCH3), 2.56 (m, 2 H, CH2), (m, 1 H, 6exo-C6H7), 1.85 (m, 6endo-C6H7, CH2), 1.94, 2.01, 2.03
2.78 (m, 1 H, 1-C6H7), 3.24 (m, 2 H, 2,5-C6H7), 4.38Ϫ4.64 [m, 2 [each s, together 3 H, SCH3 (1:1:2)], 2.50 (m, 3 H, 1-C6H7, CH2),
H, PhCONHCH, CONHCH(CH2Ph)], 5.57 (m, 2 H, 3,4-C6H7), 2.98 (m, 2 H, 2,5-C6H7), 3.52, 3.74 [each m, together 1 H,
7.43Ϫ7.57 (m, 3 H, 3,4,5-C6H5), 7.88Ϫ7.95 (m, 2 H, 2,6-C6H5). Ϫ NCH(CH2CH2SCH3)COO], 4.40 [m, 1 H, NHCH(C6H7)CON],
C23H24FeN2O7S (528.4): calcd. C 52.29, H 4.58, N 5.30; found C
52.73, H 4.70, N 5.27.
5.31 (m, 2 H, 3,4-C6H7), 7.08Ϫ7.89 (m, 35 H, 7 C6H5). Ϫ 31P
1
NMR: δ ϭ 2.79, 2.80, 2.91, 2.97 (each d, 2JP-P ϭ 19.2 Hz, JP-Pt ϭ
3690 Hz, P trans to O), 18.24, 18.25, 18.34, 18.41 ( each d, 2JP-P
19.2 Hz, JP-Pt ϭ 3881 Hz, P trans to N). Diastereomeric ratio
about 1:1:1:2. Ϫ C59H52FeN2O7P2PtS ϫ CH2Cl2 (1330.9): calcd. C
54.15, H 4.09, N 2.11; found C 53.53, H 4.23, N 2.31.
ϭ
22: 95 mg (0.171 mmol) of 18, 3.5 ml of 0.1  NaOH and 3.5 ml
of 0.1  HCl were used. Four stereoisomers. Ϫ IR (KBr): ν˜ ϭ 3429
cmϪ1 s br. (OϪH, NϪH), 2047 s (FeϪCO), 1971 s br. (FeϪCO),
1723 s, 1720 s (2 COOH), 1644 s (CONH-I), 1527 s (CONH-II).
1
Ϫ
1H NMR (270 MHz, [D6]acetone): δ ϭ 1.59 (m, 1 H, 6exo-
X-ray Diffraction Analyses[18]: Data collection: Enraf Nonius
CAD4 Diffractometer (4, 5), Siemens P4 Diffractometer (9, 10),
C6H7), ca. 2.00 (m, 6endo-C6H7, CH2), 2.42 (m, 2 H, CH2), 2.84 (m,
1 H, 1-C6H7), 3.20 (m, 2 H, 2,5-C6H7), 4.50 [m, 2 H, PhCONHCH,
CONHCH(CH2Ph)], 5.54 (m, 2 H, 3,4-C6H7), 7.41Ϫ7.62 (m, 3 H,
3,4,5-C6H5), 7.87Ϫ7.95 (m, 2 H, 2,6-C6H5). Ϫ C23H22FeN2O9
(526.3): calcd. C 52.49, H 4.21, N 5.32; found C 52.33, H 3.94,
N 5.04.
˚
Mo-Kα radiation, λ ϭ 0.71073 A, graphite monochromator, cell
constants from 25 centered reflections, ω-2Θ scan, intensity of three
standard reflections checked every 2 h. Structure solution by
SHELXS-86 and refinement by SHELXL-93 (G. M. Sheldrick,
University of Göttingen, Germany), non-hydrogen atoms refined
anisotropically, hydrogen atoms with Ui ϭ 1.2 ϫ Ueq of the adja-
General Procedure for the Preparation of 23Ϫ25: To a solution
of (COD)PtCl2 in 10 ml of CH2Cl2 two equiv. of PPh3, one equiva- cent carbon atom (4, 5, 10). For 9 hydrogen atoms found and re-
lent of 19Ϫ21 and a slight excess of Ag2O were added. This mixture
fined freely. Full-matrix refinement against F2. See Table 1 for crys-
was refluxed in the dark for 6 h and then, after cooling to room
tal data and structure refinement.
Eur. J. Inorg. Chem. 1998, 485Ϫ493
491

W. Bauer, M. Prem, K. Polborn, K. Sünkel, W. Steglich, W. Beck
Table 1. Crystal data and structure refinement for 4, 5, 9 and 10
FULL PAPER
Compound number
Empirical formula
4 (M1403)[a]
5 (M1550)
9
10
2 ϫ C29H36Cl3Ir2NO2
ϫ 1.5 CH2Cl2
1970.06
295(2)
monoclinic
C19H21NO12Pd3
C19H13CrNO5
C20H15CrNO5
Formula weight
T [K]
Crystal system
Space group
774.57
294(2)
triclinic
387.30
293(2)
monoclinic
C2/c
401.33
293(2)
monoclinic
P21/n
¯
P21/c (No. 14)
P1 (No. 2)
Unit-cell dimensions
˚
a [A]
18.0641(19)
17.3233(24)
21.5724(38)
90
91.048(11)
90
6749.5(1.7)
4
1.939
8.562(3)
941.8(3)
31.384(2)
6.6040(10)
16.7890(10)
90
106.92(11)
90
3329.1(6)
8
1.546
9.0240(10)
10.373(3)
19.333(5)
90
101.040(10)
90
1776.2(7)
4
˚
b [A]
˚
c [A]
15.907(4)
101.72(2)
92.73(2)
108.61(2)
1181.5(6)
2
2.177
2.323
752
α [°]
β [°]
γ [°]
3
˚
V [A ]
Z
Density (calcd.) [g/cm3]
1.501
0.676
824
µ (Mo-Kα) [mmϪ1
F(000)
]
8.261
3756
0.718
1584
Crystal size [mm]
2θ range [°]
Index ranges
Reflections collected
Independent reflections
Absorption correction
0.43 ϫ 0.37 ϫ 0.10
4.96Ϫ48.02
±h ϩk ϩl
10544
10253 [R(int) ϭ 0.0447]
ψ scan
0.47 ϫ 0.27 ϫ 0.07
4.68Ϫ47.94
Ϫh ±k ±l
3978
3693 [R(int) ϭ 0.0171]
ψ scan
0.55 ϫ 0.23 ϫ 0.08
5Ϫ50
ϩh ϩk ±l
3680
2921 [R(int) ϭ 0.0372]
ψ scan
0.05 ϫ 0.10 ϫ 0.38
4.3Ϫ50
ϩh ϩk ±l and Ϫh Ϫk ±l
6657
3133 [R(int) ϭ 0.1596]
N/A
Max. and min. transmission 0.991 and 0.240
0.998 and 0.683
3239/321
1.079
0.238 and 0.209
2921/274
1.038
Data/parameters
7643/798
1.076
3133/244
0.990
Goodness-of-fit on F2
Final R indices [I > 2σ(I)]
R indices (all data)
R1 ϭ 0.0451, wR2 ϭ 0.1077 R1 ϭ 0.0247, wR2 ϭ 0.0640 R1 ϭ 0.0434, wR2 ϭ 0.0783 R1 ϭ 0.0753, wR2 ϭ 0.1057
R1 ϭ 0.0685, wR2 ϭ 0.1260 R1 ϭ 0.0309, wR2 ϭ 0.0686 R1 ϭ 0.0847, wR2 ϭ 0.0933 R1 ϭ 0.1961, wR2 ϭ 0.1412
Largest diff. peak and
1.639 and Ϫ1.381
0.557 and Ϫ0.539
0.212 and Ϫ0.273
0.374 and Ϫ0.401
Ϫ3
˚
hole [eA
]
[a]
Two independent molecules, 1.5 CH2Cl2 disordered, split, Cp* disordered, not split.
[1]
Tetrahedron Lett. 1996, 37, 6561Ϫ6564; M. Schweiger, T. Ede-
rer, K. Sünkel, W. Beck, J. Organomet. Chem., in press.
S. Sprouse, K. A. King, P. J. Spellane, R. J. Watts, J. Am. Chem.
Soc. 1984, 106, 6647Ϫ6653; J. F. van Baar, K. Vrieze, P. J. Stuf-
kens, J. Organomet. Chem. 1975, 85, 249Ϫ263; M. Nonoyama,
J. Organomet. Chem. 1975, 86, 263Ϫ267; P. L. Bellon, F. de
Martin, M. Manassero, M. Sansoni, J. Organomet. Chem. 1978,
157, 209Ϫ217; N. Farrell, D. Sutton, J. Chem. Soc., Dalton
Trans. 1977, 2124Ϫ2128; J. A. Carroll, R. E. Cobbledick, F. W.
B. Einstein, N. Farrell, D. Sutton, P. L. Vogel, Inorg. Chem.
1977, 16, 2462Ϫ2469; L. Dahlenburg, F. Mirzaei, J. Organomet.
Chem. 1983, 251, 123Ϫ132; J. A. Carroll, D. Sutton, Z.
Xiaoheng, J. Organomet. Chem. 1982, 244, 73Ϫ86; K. A. King,
P. J. Spellane, R. J. Watts, J. Am. Chem. Soc. 1985, 107,
1431Ϫ1432; A. C. Albe´niz, G. Schulte, R. H. Crabtree, Or-
ganometallics 1992, 11, 242Ϫ249; P. Didier, I. Ortmans, A.
Kirsch-De Mesmaeker, R. J. Watts, Inorg. Chem. 1993, 32,
5239Ϫ5245.
B. Kayser, C. Missling, J. Knicek, H. Nöth, W. Beck, Eur. J.
Inorg. Chem. 1998, 375Ϫ379.
[7]
[2]
[3]
X-ray structure analyses.
W. Steglich, Fortschr. Chem. Forsch. 1969, 12, 77Ϫ118; R.
Lohmar, W. Steglich, Chem. Ber. 1980, 113, 3706Ϫ3715; G.
Schulz, W. Steglich, Chem. Ber. 1980, 113, 770Ϫ786; B. Kübel,
P. Gruber, R. Hurnaus, W. Steglich, Chem. Ber. 1979, 112,
128Ϫ137; G. Schulz, P. Gruber, W. Steglich, Chem. Ber. 1979,
112, 3221Ϫ3236; W. Steglich, P. Gruber, H.-U. Heininger, F.
Kneidl, Chem. Ber. 1971, 104, 3816Ϫ3830; J. Leyendecker, U.
Niewohner, W. Steglich, Tetrahedron Lett. 1983, 24, 2375Ϫ2378;
E. Bunuel, C. Cativiela, M. D. Diaz-de-Villegas, Tetrahedron:
Asym. 1996, 7, 1431Ϫ1436; R. M. Ortuno, J. Ibarzo, J. dЈAn-
gelo, F. Dumas, A. Alvarez-Larena, J. F. Piniella, Tetrahedron:
Asym. 1996, 7, 127Ϫ138; D. Obrecht, C. Abrecht, M. Altorfer,
U. Bohdal, A. Grieder, M. Kleber, P. Pfyffer, K. Müller, Helv.
Chim. Acta 1996, 79, 1315Ϫ1337; M. L. Gelmi, F. Clerici, A.
Melis, Tetrahedron 1997, 53, 1843Ϫ1854; M. Hugener, H.
Heimgartner, Helv. Chim. Acta 1995, 78, 1863Ϫ1878; F. Cave-
lier, J. Verducci, Tetrahedron Lett. 1995, 36, 4425Ϫ4428.
B. Schreiner, M. Prem, W. Bauer, K. Polborn, W. Beck, Z. Na-
turforsch., Part B, in press.
[8]
[9]
A. C. Skapski, M. L. Smart, J. Chem. Soc., Chem. Commun.
1970, 658Ϫ659.
[4]
[5]
W. Beck, B. Niemer, M. Wieser, Angew. Chem. 1993, 105,
969Ϫ996; Angew. Chem. Int. Ed. Engl. 1993, 32, 923Ϫ950; L.
A. P. Kane-Maguire, E. D. Honig, D. A. Sweigart, Chem. Rev.
1984, 84, 525Ϫ543 and ref. therein; A. J. Pearson, Trans. Met.
Chem. 1981, 6, 67Ϫ78 and ref. therein; A. J. Birch, L. F. Kelly,
A. S. Narula, Tetrahedron 1982, 38, 1813Ϫ1823; J. A. Carrer,
B. Fates, L. A. P. Kane-Maguire, J. Chem. Soc., Chem. Com-
mun. 1993, 928Ϫ929; L. A. P. Kane-Maguire, R. Kanitz, P.
Jones, P. A. Williams, J. Organomet. Chem. 1994, 464, 203Ϫ213;
H.-J. Knölker, Synlett 1992, 371Ϫ387; H.-J. Knölker, J. Prakt.
Chem./Chem.-Ztg. 1996, 338, 190Ϫ193.
See, e.g.: S. Jaroch, T. Schwarz, W. Steglich. P. Zistler, Angew.
Chem. 1993, 105, 1803Ϫ1805; Angew. Chem. Int. Ed. Engl.
1993, 32, 1771Ϫ1773.
D. A. Buckingham, L. G. Marzilli, A. M. Sargeson, J. Am.
Chem. Soc. 1967, 89, 2772Ϫ2773 and 4539Ϫ4540.
T. G. Appleton, J. R. Hall, P. D. Prenzler, Inorg. Chem. 1989,
28, 815Ϫ819; Y.-Q. Gong, Y.-F. Cheng, J.-M. Gu, X.-R. Ha,
W. Steglich, P. Gruber, G. Höfle, W. König, Angew. Chem. 1971,
83, 725Ϫ728; Angew. Chem. Int. Ed. Engl. 1971, 10, 653Ϫ656;
H. Wegmann, W. Steglich, Chem. Ber. 1981, 114, 2580Ϫ2594.
G. Jaouen, A. Vessieres, I. S. Butler, Acc. Chem. Res. 1993, 26,
361Ϫ369; D. P. Smith, M. T. Criffin, M. M. Olmstead, M. F.
Maestre, R. H. Fish, Inorg. Chem. 1993, 32, 4677Ϫ4678; F. V.
Sloop, G. M. Brown, R. A. Sachleben, M. L. Garrity, J. E.
Elbert, K. D. Jacobson, New. J. Chem. 1994, 18, 317Ϫ326; J.
M. Wolff, W. S. Sheldrick, Chem.Ber. 1997, 130, 981Ϫ988 and
ref. therein; B. Kayser, K. Polborn, W. Steglich, W. Beck, Chem.
Ber. 1997, 130, 171Ϫ177; J. M. Wolff, W. S. Sheldrick, J. Or-
ganomet. Chem. 1997, 531, 141Ϫ149 and ref. therein; R.
Krämer, Angew. Chem. 1996, 108, 1287Ϫ1289; Angew. Chem.
Int. Ed. Engl. 1996, 35, 1197Ϫ1199; D. Osella, M. Ravera, M.
Vincenti, M. Salmain, G. Jaouen, Organometallics 1996, 15,
[6]
[10]
[11]
[12]
´
3037Ϫ3041; S. Blanalt, M. Salmain, B. Malezieux, G. Jaouen,
492
Eur. J. Inorg. Chem. 1998, 485Ϫ493

Metal Complexes of Biologically Important Ligands, CII
FULL PAPER
[15]
[16]
[17]
[18]
Polyhedron 1997, 3743, R. D. W. Kemmitt, S. Mason, J. Fawcett,
D. R. Russell, J. Chem. Soc., Dalton Trans. 1992, 1165Ϫ1176;
H. Sigel, R. B. Martin, Chem. Rev. 1982, 82, 385Ϫ426; A. Bona-
martini Corradi, E. Gozzoli, L. Menabue, M. Saladini, L. P.
Battaglia, P. Sgarabotto, J. Chem. Soc., Dalton Trans. 1994,
273Ϫ278 and ref. therein; G. Battistuzzi, M. Borsari, L. Me-
nabue, M. Saladini, Inorg. Chem. 1996, 35, 4239Ϫ4247 and ref.
therein; D. B. Grotjahn, T. L. Groy, Organometallics 1995, 14,
3669Ϫ3682.
J. D. Munro, P. L. Pauson, J. Chem. Soc. 1961, 3475Ϫ3486.
D. Drew, J. R. Doyle, Inorg. Synth. 1990, 28, 346Ϫ347.
R. Lohmar, W. Steglich, Chem. Ber. 1980, 113, 3706Ϫ3715.
Further details of the crystal structure determinations are avail-
able from the Fachinformationszentrum Karlsruhe, D-76344
Eggenstein-Leopoldshafen (Germany), on quoting the deposi-
tory numbers CSD-407619 (4), -407618 (5), and from the Cam-
bridge Crystallographic Data Centre, 12 Union Road, Cam-
bridge CB2 1EZ (UK) on quoting the depository number
CCDC-100699 (9, 10).
[13]
J. W. Kang, M. Mosley, P. M. Maitlis, J. Am. Chem. Soc. 1969,
91, 5970Ϫ5977; P. M. Maitlis, Acc. Chem. Res. 1978, 11,
301Ϫ307.
[97269]
[14]
D. Jones, L. Pratt, G. Wilkinson, J. Chem. Soc. 1962,
4458Ϫ4463.
Eur. J. Inorg. Chem. 1998, 485Ϫ493
493