Synthesis and characterization of osmium nitrosyl porphyrins containing organo, halogeno, and μ-Oxo ligands, and extensions to the first organometallic thionitrosyl porphyrin

Article abstract of DOI:10.1021/om980197s

The sequential reaction of (OEP)Os(CO) with NOPF₆ (in CH₂Cl₂) followed by RMgX (in THF) gives variable isolated yields of the new (OEP)Os(NO)R (5-44%), (OEP)Os(R)₂ (1-10%), (OEP)Os(NO)X (14-19%), and [(OEP)Os(NO

Full text of DOI:10.1021/om980197s

Organometallics 1998, 17, 3853-3864
3853
Syn th esis a n d Ch a r a cter iza tion of Osm iu m Nitr osyl
P or p h yr in s Con ta in in g Or ga n o, Ha logen o, a n d µ-Oxo
Liga n d s, a n d Exten sion s to th e F ir st Or ga n om eta llic
Th ion itr osyl P or p h yr in
Lin Cheng, Li Chen, Hee-Sun Chung, Masood A. Khan, and
George B. Richter-Addo*
Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval,
Norman, Oklahoma 73019
Victor G. Young, J r.
X-ray Structural Laboratory, Department of Chemistry, University of Minnesota,
207 Pleasant Street Southeast, Minneapolis, Minnesota 55455
Received March 17, 1998
The sequential reaction of (OEP)Os(CO) with NOPF6 (in CH2Cl2) followed by RMgX (in
THF) gives variable isolated yields of the new (OEP)Os(NO)R (5-44%), (OEP)Os(R)2 (1-
10%), (OEP)Os(NO)X (14-19%), and [(OEP)Os(NO)]2(µ-O) (up to 24%) compounds, depending
on the reaction conditions and the nature of R and X (OEP ) octaethylporphyrinato dianion;
i
t
R ) Me, Et, Pr, Bu, p-C6H4F; X ) Cl, Br). The IR υNO values of the complexes (in CH2Cl2)
decrease in the order (OEP)Os(NO)X (1799-1795 cm-1) > [(OEP)Os(NO)]2(µ-O) (1770 cm-1
)
> (OEP)Os(NO)R (1748-1703 cm-1). The δmeso peaks in the H NMR spectra of the (OEP)-
Os complexes (in CDCl3) also decrease in the order (OEP)Os(NO)X (10.41-10.40 ppm) >
[(OEP)Os(NO)]2(µ-O) (10.35 ppm) > (OEP)Os(NO)R (10.24-10.21 ppm) > (OEP)Os(R)2 (9.71-
9.03 ppm). The thionitrosyl (OEP)Os(NS)Cl and (OEP)Os(NS)Me compounds have also been
prepared. The solid-state molecular structures of [(OEP)Os(NO)]2(µ-O), (OEP)Os(NS)Cl, and
(OEP)Os(NS)Me have been determined by single-crystal X-ray diffraction.
1
Ch a r t 1
Several types of organometallic porphyrins are now
known (Chart 1), and their varied natures have allowed
diverse investigations into their chemical and spectro-
scopic properties.1-3 Organometallic porphyrins of type
A comprise those with metal-carbon(alkyl/aryl) single
or multiple bonds. Dialkyl(aryl) complexes of the form
(por)M(R)2 have also been structurally characterized,
and the σ-R ligands may either be located cis to each
other (e.g., as in (OEP)Zr(Me)2)4,5 or located trans to
each other (e.g., as in (TTP)Os(CH2SiMe3)2) (OEP )
2,3,7,8,12,13,17,18-octaethylporphyrinato dianion, TTP
) 5,10,15,20-tetra-p-tolylporphyrinato dianion).6,7
Organometallic porphyrins of type B include those
with η2-alkene/alkyne or other π-bonded groups such as
cyclopentadienyl or indenyl ligands.1,9-12 Type C com-
plexes contain µ-N,M units in which the bridging alkyl
(1) Brothers, P. J .; Collman, J . P. Acc. Chem. Res. 1986, 19, 209-
215.
(2) Setsune, J .-I.; Dolphin, D. Can. J . Chem. 1987, 65, 459-467.
(3) Guilard, R.; Lecomte, C.; Kadish, K. M. Struct. Bonding 1987,
64, 205-268.
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(6) Leung, W.-H.; Hun, T. S. M.; Wong, K.-Y.; Wong, W.-T. J . Chem.
Soc., Dalton Trans. 1994, 2713-2718.
(7) A cis alkyl-hydroxyl complex has been recently proposed as an
alternate intermediate in the cytochrome P450 rebound mechanism.8
(8) Collman, J . P.; Chien, A. S.; Eberspacher, T. A.; Brauman, J . I.
J . Am. Chem. Soc. 1998, 120, 425-426.
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Wright, L. J . J . Am. Chem. Soc. 1985, 107, 4570-4571.
(or carbene, vinyl, etc.) group maintains direct contact
with the metal center.1,2,13,14 The related nonorgano-
metallic N-alkyl(aryl) porphyrins, in which there is no
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1660.
(11) Collman, J . P.; Brothers, P. J .; McElwee-White, L.; Rose, E. J .
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Organometallics 1993, 12, 3645-3654.
S0276-7333(98)00197-6 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 07/23/1998

3854 Organometallics, Vol. 17, No. 18, 1998
Cheng et al.
direct metal-alkyl(aryl) interaction, are also known.1,14-20
Type D complexes have been reported recently, in which
the pyrrole ring of a porphyrin fragment is π-bound to
a second metal moiety.21-23 Type E complexes have
been described, in which an external metal-containing
fragment is (i) bound to an aryl substituent in either a
π- or σ-bound fashion or (ii) bound via an organic moiety
to the central metal of the metalloporphyrin.26-29
Interest in the study of organometallic complexes
containing a direct M-R interaction (e.g., in types A-C)
results from the detection and/or postulation of orga-
nometallic species in the natural and model chemistry
of coenzyme B12, cytochrome P450, and other heme-
containing biomolecules.1,2,30,31 In this regard, many Co
model systems for coenzyme B12 have been synthesized
and studied.32-36
only a handful of organoosmium porphyrins have been
reported to date.6,11,43,49,50 Interestingly, some (por)Fe-
(R) complexes (of type A) react with NO gas to form
nitrosyl adducts (eq 1).51,52 In some cases, the known
(por)Fe(R) + NO f (por)Fe(NO)R
por ) OEP, TPP; R ) alkyl, aryl
(1)
(por)Fe(NO) complexes are produced instead. We re-
cently reported the synthesis and characterization of
analogous Ru complexes (type A) via the reaction of the
(TTP)Ru(NO)Cl precursor with Grignard reagents (eq
2).44 We also reported the single-crystal X-ray struc-
(TTP)Ru(NO)Cl + RMgX f (TTP)Ru(NO)R (2)
R ) Me, p-C6H4F
The reported organometallic chemistry of group 8
metalloporphyrins has so far been focused on those of
iron3,37-40 and ruthenium.9,11,14,15,18,41-49 Surprisingly,
tural characterization of a representative complex,
namely that of (TTP)Ru(NO)(p-C6H4F). We attempted
to extend the reaction outlined in eq 2 to osmium
porphyrins but were only able to obtain the desired
organoosmium products in very low (<5%) yields.
However, we have found that the sequential reaction
of (por)Os(CO) with NOPF6 and then RMgX gives
isolable quantities of the desired (por)Os(NO)R com-
plexes (type A) together with other Os nitrosyl and non-
nitrosyl porphyrin products. This latter finding is the
subject of this paper. To the best of our knowledge, this
is the first report on organoosmium nitrosyl porphyrins.
Our successful extension to the synthesis and structural
characterization of osmium thionitrosyl porphyrins is
also reported.
(13) Setsune, J .-I.; Saito, Y.; Ishimary, Y.; Ikeda, M.; Kitao, T. Bull.
Chem. Soc. J pn. 1992, 65, 639-648.
(14) Seyler, J . W.; Safford, L. K.; Fanwick, P. E.; Leidner, C. R. Inorg.
Chem. 1992, 31, 1545-1547.
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(16) Lanc¸on, D.; Cocolios, P.; Guilard, R.; Kadish, K. M. J . Am.
Chem. Soc. 1984, 106, 4472-4478.
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Simonet, B.; Kadish, K. M. Inorg. Chem. 1985, 24, 2509-2520.
(18) Seyler, J . W.; Leidner, C. R. J . Chem. Soc., Chem. Commun.
1989, 1794-1796.
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4348-4351.
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Acta 1990, 171, 205-212.
(21) Senge, M. O. Angew. Chem., Int. Ed. Engl. 1996, 35, 1923-
1925 and references therein.
(22) Dailey, K.; Rauchfuss, T. B. Polyhedron 1997, 16, 3129-3136.
(23) Related η5-pyrrole porphyrinogen complexes have also been
structurally characterized.24,25
Exp er im en ta l Section
(24) J acoby, D.; Isoz, S.; Floriani, C.; Chiesi-Villa, A.; Rizzoli, C. J .
Am. Chem. Soc. 1995, 117, 2805-2816.
Gen er a l Com m en ts. All reactions were performed under
an atmosphere of prepurified nitrogen using standard Schlenk
techniques and/or in an Innovative Technology Labmaster 100
Dry Box unless stated otherwise. All column chromatography
was done under nitrogen. Solvents were distilled from ap-
propriate drying agents under nitrogen just prior to use: CH2-
Cl2 (CaH2), THF (Na/benzophenone), hexane (Na/benzophenone/
tetraglyme), and benzene (Na). Solutions for spectral studies
were prepared under a nitrogen atmosphere and measured
immediately.
Ch em ica ls. (TTP)Os(CO) and (OEP)Os(CO) were prepared
by literature methods (TTP ) 5,10,15,20-tetra-p-tolylporphy-
rinato dianion, OEP ) 2,3,7,8,12,13,17,18-octaethylporphyri-
nato dianion).54 (NSCl)3 was prepared by literature method.55
The labeled (15NSCl)3 analogue was prepared similarly using
15NH4Cl (Isotec). Nitrosyl chloride was prepared by the
(25) J acoby, D.; Isoz, S.; Floriani, C.; Chiesi-Villa, A.; Rizzoli, C. J .
Am. Chem. Soc. 1995, 117, 2793-2804.
(26) Uosaki, K.; Kondo, T.; Zhang, X.-Q.; Yanagida, M. J . Am. Chem.
Soc. 1997, 119, 8367-8368.
(27) Beer, P. D.; Drew, M. G. B.; J agessar, R. J . Chem. Soc., Dalton
Trans. 1997, 881-886.
(28) Wagner, R. W.; Brown, P. A.; J ohnson, T. E.; Lindsey, J . S. J .
Chem. Soc., Chem. Commun. 1991, 1463-1466.
(29) Zakrzewski, J .; Giannotti, C. Coord. Chem. Rev. 1995, 140,
169-187.
(30) Mansuy, D. Pure Appl. Chem. 1987, 59, 759-770.
(31) Kra¨utler, B. In Encyclopedia of Inorganic Chemistry; King, R.
B., Ed.; J ohn Wiley and Sons: Chichester, 1994; Vol. 2, pp 697-712.
(32) Brown, K.; Cheng, S.; Zou, X.; Zubkowski, J . D.; Valente, E. J .;
Knapton, L.; Marques, H. M. Inorg. Chem. 1997, 36, 3666-3675.
(33) Gridnev, A. A.; Ittel, S. D.; Fryd, M.; Wayland, B. B. Organo-
metallics 1996, 15, 222-235.
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Soc. 1994, 116, 7189-7195.
(35) Kadish, K. M.; Han, B. C.; Endo, A. Inorg. Chem. 1991, 30,
4502-4506.
(36) Chopra, M.; Hun, T. S. M.; Leung, W.-H.; Yu, N.-T. Inorg. Chem.
1995, 34, 5973-5978.
(46) Sishta, C.; Ke, M.; J ames, B. R.; Dolphin, D. J . Chem. Soc.,
Chem. Commun. 1986, 787-788.
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5228-5229.
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W.; Ibers, J . A. Inorg. Chem. 1991, 30, 4766-4771.
(38) Li, Z.; Goff, H. M. Inorg. Chem. 1992, 31, 1547-1548.
(39) Song, B.; Goff, H. M. Inorg. Chim. Acta 1994, 226, 231-235.
(40) Kadish, K. M.; Tabard, A.; Lee, W.; Liu, Y. H.; Ratti, C.; Guilard,
R. Inorg. Chem. 1991, 30, 1542-1549.
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31, 3699-3700.
(49) Collman, J . P.; Ha, Y.; Wagenknecht, P. S.; Lopez, M.-A.;
Guilard, R. J . Am. Chem. Soc. 1993, 115, 9080-9088.
(50) The organometallic chemistry of Ru and Os complexes with η1-
carbon ligands has been reviewed, see: Hill, A. F. In Comprehensive
Organometallic Chemistry II. A Review of the Literature 1982-1994,
1st ed.; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon:
Exeter, U.K., 1995; Vol. 7, pp 299-440.
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1994, 13, 2542-2544.
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Am. Chem. Soc. 1986, 108, 1332-1334.
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Commun. 1994, 11-12.
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M. Inorg. Chem. 1985, 24, 3649-3656.
(52) The (TPP)Fe(NO)(C5H5) complex has been claimed to be
isolated,53 although its reported υNO of 1705 cm-1 is very close to that
of the known (TPP)Fe(NO) (υNO ) 1699 cm-1).
(44) Hodge, S. J .; Wang, L.-S.; Khan, M. A.; Young, V. G.; Richter-
Addo, G. B. Chem. Commun. 1996, 2283-2284.
(45) Ke, M.; Rettig, S. J .; J ames, B. R.; Dolphin, D. J . Chem. Soc.,
Chem. Commun. 1987, 1110-1112.

Synthesis of Osmium Nitrosyl Porphyrins
Organometallics, Vol. 17, No. 18, 1998 3855
literature method.56 NOPF6 (96%) and all Grignard reagents
used were purchased from Aldrich Chemical Co. Chloroform-d
(99.8%) and benzene-d6 (99.6%) were obtained from Cambridge
Isotope Laboratories, subjected to 3 freeze-pump-thaw cycles,
and stored over Linde 4 Å molecular sieves. Elemental
analyses were performed by Atlantic Microlab, Norcross, GA.
In str u m en ta tion . Infrared spectra were recorded on a
Bio-Rad FT-155 FTIR spectrometer. 1H NMR spectra were
obtained on a Varian 400 MHz spectrometer, and the signals
(in ppm) were referenced to the residual signal of the solvent
employed. All couplings are in hertz. FAB mass spectra were
obtained on a VG-ZAB-E mass spectrometer. UV-vis spectra
were recorded on a Hewlett-Packard model 8453 diode array
instrument. Wavelengths are reported with ꢀ values or as
%-intensities for the samples whose yields were too small for
accurate concentration measurements.
The (OEP)Os(NO)(p-C6H4F) compound was generated simi-
larly using (p-C6H4F)MgBr (1.0 M in THF, 6-fold excess, 30
min reaction time) in 13% yield, with (OEP)Os(p-C6H4F)2 (3%),
(OEP)Os(NO)Br (19%), and [(OEP)Os(NO)]2(µ-O) (<5%) as the
other isolated products. When the reaction was performed at
room temperature (see next section), however, only (OEP)Os-
(NO)(p-C6H4F) and (OEP)Os(p-C6H4F)2 were formed in 20%
and 10% isolated yields, respectively (i.e., the intermediate
(OEP)Os(NO)Br is consumed in the reaction).
Meth od II. The following reaction is representative of the
room-temperature reactions: To a CH2Cl2 (20 mL) solution of
(OEP)Os(CO) (0.060 g, 0.08 mmol) was added NOPF6 (96%,
0.015 g, 0.082 mmol). The color of the solution changed from
pink to dark red. The mixture was left to stir for 30 min, and
all the solvent was removed. The solid was redissolved in THF
(20 mL) at room temperature, and excess MeMgBr (0.7 mmol)
was added. No substantial color change was observed. The
solvent was removed immediately after adding the MeMgBr
reagent, and the residue was dissolved in a minimum amount
of benzene and quickly filtered through a silica gel column.
All the solvent was removed from the filtrate, and the red solid
was dried in vacuo for 5 h to give (OEP)Os(NO)(Me) (0.027 g,
0.035 mmol, 44% yield).
P r ep a r a tion of (P or p h yr in )Os(NO)(R) Com p ou n d s (R
)
tBu , iP r , Et, Me, p-C6H4F ). These compounds were
synthesized either at low temperature or at room temperature.
Meth od I. The following reaction is representative: To a
solution of (OEP)Os(CO) (0.080 g, 0.107 mmol) in CH2Cl2 (10
mL) was added NOPF6 (0.020 g, 0.114 mmol). The mixture
was stirred under reduced lighting for 1 h. The solvent was
removed in vacuo, and the resulting dark red solid was
redissolved in THF (10 mL). The mixture was cooled to -30
The (OEP)Os(NO)(iPr) compound was prepared similarly in
30% yield.
The (TTP)Os(NO)Me compound was generated similarly in
35% yield from the sequential reaction of (TTP)Os(CO) with
NOPF6 and then MeMgCl as described above.
A 2:1 mixture of (OEP)Os(NO)Et and (OEP)Os(Et)2 is
produced from the room-temperature reaction (using EtMgCl)
in 39% overall yield.
t
°C, and BuMgCl (0.30 mL, 0.30 mmol, 1.0 M in THF) was
added dropwise. The stirred reaction mixture was kept
between -20 and -30 °C. Monitoring the reaction by TLC
(silica gel, 1:1 benzene/hexane) showed that the [(OEP)Os(NO)]-
PF6 intermediate was consumed within a 30 min period. The
solvent was removed in vacuo. The red residue was dissolved
in a minimum amount of benzene and chromatographed
(under nitrogen) on an alumina column (2 × 40 cm) prepared
in hexane. Eluting with a benzene/hexane (1:1) mixture
yielded a brown band and a red band, which were collected
separately. Removal of solvent from the brown fraction gave
(OEP)Os(tBu)2 (0.002 g, 2% yield). Removal of solvent from
the red fraction gave (OEP)Os(NO)(tBu) as a red solid (0.021
g, 24% yield). Elution was next performed with a CH2Cl2/
hexane (1:1) mixture, and a second red band was collected.
Solvent removal from this fraction gave red crystals of (OEP)-
Os(NO)Cl (0.003 g, 4% yield). Finally, a fourth red band was
eluted with a THF/hexane (1:1) solvent mixture. Removal of
the solvent from this fraction gave a residue that was
recrystallized from a CH2Cl2/hexane mixture in air to give the
[(OEP)Os(NO)]2(µ-O) oxo dimer (0.010 g, 0.007 mmol, 12%
yield based on Os).
Alter n a te P r ep a r a tion of (OEP )Os(NO)Cl a n d [(OEP )-
Os(NO)]2(µ-O). To a CH2Cl2 (20 mL) solution of (OEP)Os-
(CO) (0.060 g, 0.080 mmol) was added ClNO (0.081 mmol in
CH2Cl2) dropwise at room temperature. The reaction mixture
was stirred for 15 min. The color of the solution turned from
pink red to bright red. The reaction mixture was transferred
to the top of an alumina column and filtered using CH2Cl2 as
eluent. This filtrate was collected and taken to dryness, and
the red residue was dried in vacuo for 2 h to give (OEP)Os-
(NO)Cl (0.031 g, 0.039 mmol, 49% yield). The alumina column
was then washed with THF, and a resulting second filtrate
was obtained and collected. The solvent was removed, and
the red residue was recrystallized from CH2Cl2 (by slow solvent
evaporation under nitrogen) to give [(OEP)Os(NO)]2(µ-O)
(0.029 g, 0.019 mmol, 48% yield based on Os).
(OEP )Os(NO)(tBu ). Anal. Calcd for C40H53N5OOs: C,
59.31; H, 6.59; N, 8.65. Found: C, 59.91; H, 6.73; N, 8.38. IR
(CH2Cl2, cm-1): υNO 1703. IR (KBr, cm-1): υNO 1716 s; also
2964 m, 2931 w, 2867 w, 2832 w, 1465 m, 1445 m, 1372 w,
1316 w, 1272 m, 1228 w, 1153 m, 1110 w, 1056 m, 1020 m,
994 w, 962 w, 840 w, 746 w. 1H NMR (CDCl3, δ): 10.23 (s,
4H, meso-H of OEP), 4.12 (q, J ) 8, 16H, CH2CH3 of OEP),
1.95 (t, J ) 8, 24H, CH2CH3 of OEP), -4.66 (s, 9H, tBu). Low-
resolution mass spectrum (FAB): m/z 754 [(OEP)Os(NO)]+
(57). UV-vis spectrum (λ, benzene): 366 (100, Soret), 446 (45),
554 (18), 579 (br sh, 13) nm.
The (OEP)Os(NO)(iPr) compound was generated similarly
i
(using PrMgCl, 2.0 M in Et2O, 3-fold excess, 30 min reaction
time) in 25% yield, with (OEP)Os(iPr)2 (1%), (OEP)Os(NO)Cl
(4%), and [(OEP)Os(NO)]2(µ-O) (8%) as the other isolated
products.
The (OEP)Os(NO)(Et) compound was generated similarly
(using EtMgCl, 1.0 M in THF, 3-fold excess, 25 min reaction
time) in 17% yield, with (OEP)Os(Et)2 (5%), (OEP)Os(NO)Cl
(6%), and [(OEP)Os(NO)]2(µ-O) (8%) as the other isolated
products.
The (OEP)Os(NO)(Me) compound was generated similarly
in ca. 5% yield using (i) MeMgBr (1.4 M in toluene/THF, 2-fold
excess, 1.5 h reaction time) with (OEP)Os(NO)Br (17%) and
[(OEP)Os(NO)]2(µ-O) (12%) as the other isolated products or
(ii) MeMgCl (3.0 M in THF, 15-fold excess, 1.5 h reaction time)
with (OEP)Os(NO)Cl (16%) and [(OEP)Os(NO)]2(µ-O) (24%) as
the other isolated products.
(OEP )Os(NO)(iP r ). Anal. Calcd for C39H51N5OOs‚0.35CH2-
Cl2: C, 57.23; H, 6.31; N, 8.48; Cl, 3.01. Found: C, 57.34; H,
6.57; N, 7.73; Cl, 2.83. IR (CH2Cl2, cm-1): υNO 1703. IR (KBr,
cm-1): υNO 1715 s; also 2965 w, 2928 w, 2868 w, 1609 m, 1534
vw, 1464 m, 1446 m, 1372 m, 1316 w, 1272 m, 1218 w, 1151
m, 1110 w, 1056 m, 1019 s, 994 m, 962 m, 839 w, 803 w, 744
m, 713 w. 1H NMR (CDCl3, δ): 10.21 (s, 4H, meso-H of OEP),
5.28 (s, CH2Cl2), 4.12 (q, J ) 8, 16H, CH3CH2 of OEP), 1.96 (t,
J ) 8, 24H, CH3CH2 of OEP), -4.63 (d, J ) 7, 6H, (CH3)2CH
of iPr), -7.12 (sept, J ) 7, 1H, (CH3)2CH of iPr). Low-
resolution mass spectrum (FAB): m/z 798 [(OEP)Os(NO)(iPr)
+ H]+ (6), 767 [(OEP)Os(iPr)]+ (9), 754 [(OEP)Os(NO)]+ (27),
724 [(OEP)Os]+ (15). UV-vis spectrum (λ (ꢀ, mM-1 cm-1), 1.68
× 10-5 M in CH2Cl2): 359 (62), 446 (34), 552 (13), 582 (8) nm.
(53) Massoudipour, M.; Tewari, S. K.; Pandey, K. K. Polyhedron
1989, 8, 1447-1451.
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1985, 24, 1277-1278.
(55) J olly, W. L.; Maguire, K. D. Inorg. Synth. 1967, 9, 102-111.
(56) Pass, G.; Sutcliffe, H. Practical Inorganic Chemistry: Prepara-
tions, Reactions and Instrumental Methods; Chapman and Hall:
London, U.K., 1968; pp 145-146.

3856 Organometallics, Vol. 17, No. 18, 1998
Cheng et al.
(OEP )Os(NO)Et. Anal. Calcd for C38H49N5OOs: C, 58.36;
H, 6.32; N, 8.96. Found: C, 58.12; H, 6.29; N, 8.70. IR (CH2-
Cl2, cm-1): υNO 1710. IR (KBr, cm-1): υNO 1717 s; also 2967
m, 2933 w, 2871 w, 1272 w, 1152 w, 1111 w, 1056 w, 1020 m,
995 w, 964 w, 839 w, 745 w. 1H NMR (CDCl3, δ): 10.21 (s,
4H, meso-H of OEP), 4.12 (q, J ) 8, 16H, CH2CH3 of OEP),
1.96 (t, J ) 8, 24H, CH2CH3 of OEP), -4.62 (t, J ) 8, 3H, CH3
of Et), -7.45 (q, J ) 8, 2H, CH2 of Et). UV-vis spectrum (λ,
CH2Cl2): 355 (100, Soret), 446 (61), 553 (22), 583 (12) nm.
(OEP )Os(tBu )2. 1H NMR (CDCl3, δ): 9.03 (s, 4H, meso-H
of OEP), 3.93 (q, J ) 8, 16H, CH3CH2 of OEP), 1.80 (t, J ) 8,
t
24H, CH3CH2 of OEP), -3.18 (s, 9H, Bu).
(OEP )Os(Et)2. 1H NMR (CDCl3, δ): 9.23 (s, 4H, meso-H
of OEP), 3.67 (q, J ) 8, 16H, CH3CH2 of OEP), 1.73 (t, J ) 8,
24H, CH3CH2 of OEP), -0.72 (q, J ) 7, 4H, CH3CH2 of Et),
-4.77 (t, J ) 7, 6H, CH3CH2 of Et).
(OEP )Os(Me)2. 1H NMR (CDCl3, δ): 9.34 (s, 4H, meso-H
of OEP), 3.70 (q, 16H, J ) 8, CH3CH2 of OEP), 1.74 (t, J ) 8,
24H, CH3CH2 of OEP), -1.16 (s, 6H, CH3). UV-vis spectrum
(λ, benzene): 330 (72), 371 (100, Soret), 394 (sh, 68), 440 (39),
547 (17) nm.
(OEP )Os(NO)Me. IR (CH2Cl2, cm-1): υNO 1720. IR (KBr,
cm-1): υNO 1732 s; also 2966 w, 2932 w, 2869 w, 1467 m, 1446
m, 1372 w, 1317 w, 1272 m, 1227 w, 1151 m, 1111 w, 1056 m,
(OEP )Os(p-C6H4F )2. IR (KBr, cm-1): 2964 w, 2929 w, 2869
w, 1567 w, 1474 w, 1453 w, 1262 w, 1222 m, 1158 m, 1108 w
br, 1055 w, 1018 m, 812 m. 1H NMR (CDCl3, δ): 9.71 (s, 4H,
meso-H of OEP), 5.05 (t, J ) 9, 4H, p-C6H4F), 3.91 (q, J ) 8,
16H, CH2CH3 of OEP), 1.75 (t, J ) 8, 24H, CH2CH3 of OEP),
1.15 (m, 4H, p-C6H4F). Low-resolution mass spectrum
(FAB): m/z 914 [(OEP)Os(p-C6H4F)2]+ (4), 819 [(OEP)Os(p-
C6H4F)]+ (42). UV-vis (λ, CH2Cl2): 368 (100, Soret), 493 (26),
641 (13) nm. UV-vis (λ, benzene): 369 (100, Soret), 489 (28),
641 (16) nm.
1
1020 s, 994 m, 964 m, 838 m, 802 w, 745 m, 713 m, 518 w. H
NMR (CDCl3, δ): 10.21 (s, 4H, meso-H of OEP), 4.12 (q, J )
8, 16H, CH3CH2 of OEP), 1.97 (t, J ) 8, 24H, CH3CH2 of OEP),
-8.10 (s, 3H, CH3). Low-resolution mass spectrum (FAB): m/z
770 [(OEP)Os(NO)(Me) + H]+ (4), 739 [(OEP)Os(Me)]+ (12).
UV-vis spectrum (λ (ꢀ, mM-1 cm-1), 7.81 × 10-6 M in CH2-
Cl2): 351 (67), 445 (47), 552 (15), 584 (8) nm.
(OEP )Os(NO)Cl. Anal. Calcd for C36H44N5OOsCl: Cl,
4.50. Found: Cl, 4.36. IR (CH2Cl2, cm-1): υNO 1799. IR (KBr,
cm-1): υNO 1788 s; also 2966 w, 2932 w, 2870 w, 1468 m, 1446
m, 1373 w, 1316 w, 1272 m, 1154 m, 1111 w, 1057 m, 1020 s,
994 m, 964 m, 909 w, 800 w br, 842 w. 1H NMR (CDCl3, δ):
10.41 (s, 4H, meso-H of OEP), 4.16 (m, 16H, CH2CH3 of OEP),
2.02 (t, J ) 8, 24H, CH2CH3 of OEP). Low-resolution mass
spectrum (FAB): m/z 789 [(OEP)Os(NO)Cl]+ (9), 754 [(OEP)-
Os(NO)]+ (4). UV-vis spectrum (λ (ꢀ, mM-1 cm-1), 7.81 × 10-6
M in CH2Cl2): 349 (45), 366 (42), 432 (40), 544 (12), 579 (16)
nm.
Syn th esis of (OEP )Os(NO)F .63 Meth od I. To a stirred
solution of (OEP)Os(NO)Cl (0.009 g, 0.011 mmol) in toluene
(10 mL) was added excess AgBF4 (0.010 g, 0.051 mmol). The
red color of the solution gradually deepened. Silica gel TLC
(1:1 CH2Cl2/hexane) indicated that the reaction was complete
in 30 min. The reaction solution was directly transferred onto
the top of an alumina column (2 × 40 cm) prepared in hexane.
Elution with CH2Cl2 under nitrogen generated a red band,
which was collected. Solvent removal gave (OEP)Os(NO)F
(0.008 g, 92% isolated yield). IR (CH2Cl2, cm-1): υNO 1795.
IR (KBr, cm-1): υNO 1784 s; also 2968 m, 2934 w, 2870 w, 1469
w, 1447 w, 1373 w, 1273 w, 1155 m, 1111 w, 1056 w, 1020 m,
994 w, 964 w, 843 w, 745 w, 716 w, 555 w. 1H NMR (CDCl3,
δ): 10.40 (s, 4H, meso-H of OEP), 4.17 (m, 16H, CH2CH3 of
OEP), 2.00 (t, J ) 8, 24H, CH2CH3 of OEP). Low-resolution
mass spectrum (FAB): m/z 773 [(OEP)Os(NO)F]+ (100), 754
[(OEP)Os(NO)]+ (53), 743 [(OEP)Os(F)]+ (8). UV-vis spectrum
(λ, CH2Cl2): 339 (36), 417 (100, Soret), 533 (18), 568 (33) nm.
Meth od II. To a stirred solution of (OEP)Os(CO) (0.020 g,
0.027 mmol) in CH2Cl2 (10 mL) was added excess NOPF6
(0.010 g, 0.057 mmol). The reaction mixture was stirred at
room temperature for 1 h, and silica gel TLC (CH2Cl2)
indicated that all the starting material had been consumed.
The volume of the solution was then reduced to ca. 2 mL under
vacuum, and the solution was transferred onto an alumina
column (2 × 40 cm) prepared in hexane. Elution with CH2Cl2
under nitrogen gave a red band from which (OEP)Os(NO)F
was isolated (0.003 g, 14% isolated yield). The [(OEP)Os-
(NO)]2(µ-O) compound was also obtained by eluting the
remaining residue with a 1:1 ratio of THF/hexane (0.003 g,
15% isolated yield based on Os). Some other unidentified
products remained on the column, and they were eluted with
THF.
P r ep a r a tion of (OEP )Os(NS)Cl. To a THF (25 mL)
solution of (OEP)Os(CO) (0.060 g, 0.080 mmol) was added
excess (NSCl)3 (0.014 g, 0.057 mmol). The mixture was heated
to reflux for 30 min. The color of the solution changed from
red to brown, then to green. All the solvent was then removed,
the green solid was purified by neutral alumina chromatog-
raphy with CH2Cl2 as eluent. The green fraction was collected,
and all the solvent was removed. The green residual solid was
further purified by recrystallization from CH2Cl2/hexane at
-20 °C to give (OEP)Os(NS)Cl‚0.9CH2Cl2 (0.034 g, 0.039 mmol,
49% yield). IR (KBr, cm-1): υNS 1270 s; also 2967 w, 2930 w,
2869 w, 1470 m, 1444 m, 1372 w, 1362 w, 1317 w, 1226 w,
1152 s, 1111 m, 1054 m, 1020 s, 994 m, 963 m, 839 m, 744 s,
714 m. 1H NMR (C6D6, δ): 10.65 (s, 4H, meso-H of OEP), 4.26
(s, CH2Cl2), 4.00 (q, J ) 8, 16H, CH3CH2 of OEP), 1.90 (t, J )
8, 24H, CH3CH2 of OEP). 1H NMR (CDCl3, δ): 10.49 (s, 4H,
(OEP )Os(NO)Br . Anal. Calcd for C36H44N5OOsBr: C,
51.92; H, 5.32; N, 8.41. Found: C, 51.72; H, 5.37; N, 8.05. IR
(CH2Cl2, cm-1): υNO 1796. IR (KBr, cm-1): υNO 1784 s; also
2967 m, 2933 w, 2869 w, 1468 w, 1444 w, 1273 w, 1155 m,
1112 w, 1057 w, 1020 m, 994 w, 964 w, 843 w. 1H NMR
(CDCl3, δ): 10.41 (s, 4H, meso-H of OEP), 4.17 (m, 16H, CH2-
CH3 of OEP), 2.02 (t, J ) 8, 24H, CH2CH3 of OEP). Low-
resolution mass spectrum (FAB): m/z 833 [(OEP)Os(NO)Br]+
(9), 803 [(OEP)Os(Br)]+ (3), 754 [(OEP)Os(NO)]+ (6). UV-vis
spectrum (λ, CH2Cl2): 351 (100, Soret), 369 (sh, 86), 439 (66),
548 (24), 583 (26) nm.
[(OEP )Os(NO)]2(µ-O). IR (CH2Cl2, cm-1): υNO 1770 s. IR
(KBr, cm-1): υNO 1760 s. 1H NMR (CDCl3, δ): 10.35 (s, 4H,
meso-H of OEP), 4.15 (m, 16H, CH3CH2 of OEP), 2.00 (t, J )
8, 24H, CH3CH2 of OEP). Low-resolution mass spectrum
(FAB): m/z 771 [(OEP)Os(NO)(O) + H]+ (50), 754 [(OEP)Os-
(NO)]+ (100), 724 [(OEP)Os]+ (15). UV-vis spectrum (λ (ꢀ,
mM-1 cm-1), 7.81 × 10-6 M in CH2Cl2): 341 (75), 419 (186),
533 (33), 568 (54) nm.
(TTP )Os(NO)Me. IR (CH2Cl2, cm-1): υNO 1729. IR (KBr,
cm-1): υNO 1732 m; also 3023 w, 2953 w, 2923 w, 2873 w, 1528
w, 1512 vw, 1496 w, 1446 w, 1351 m, 1306 m, 1212 m, 1179
m, 1105 w, 1069 m, 1016 s, 796 s, 718 m, 525 m. 1H NMR
(CDCl3, δ): 8.89 (s, 8H, pyr-H of TTP), 8.15 (d, J ) 7, 4H, o-H
of TTP), 8.06 (d, J ) 8, 4H, o′-H of TTP), 7.55 (app t, J ) 7/8,
8H, m-H of TTP), 2.70 (s, 12H, CH3 of TTP), -7.35 (s, 3H, Me).
UV-vis spectrum (λ (ꢀ, mM-1 cm-1), 1.44 × 10-5 M in CH2-
Cl2): 345 (sh, 44), 361 (46), 408 (45), 454 (91), 573 (13), 616
(12) nm.
(OEP )Os(NO)(p-C6H4F ). IR (CH2Cl2, cm-1): υNO 1748. IR
(KBr, cm-1): υNO 1746 s; also 2965 m, 2932 w, 2868 w, 1574
w, 1483 m, 1466 w, 1446 w, 1372 w, 1318 w, 1272 m, 1224 m,
1161 m, 1153 m, 1112 w, 1056 m, 1020 m, 993 m, 962 w, 841
w, 813 m, 746 w, 727 w, 716 w, 567 w, 501 w. 1H NMR (CDCl3,
δ): 10.24 (s, 4H, meso-H of OEP), 4.22 (m, 2H, m-H of p-C6H4F,
overlapping with OEP), 4.12 (m, 16H, CH2CH3 of OEP), 1.96
(t, J ) 8, 24H, CH2CH3 of OEP), -0.29 (t, J ) 8, 2H, o-H of
p-C6H4F). Low-resolution mass spectrum (FAB): m/z 819
[(OEP)Os(p-C6H4F)]+ (12). UV-vis spectrum (λ, benzene): 352
(Soret), 443, 552, 585 nm.

Synthesis of Osmium Nitrosyl Porphyrins
Organometallics, Vol. 17, No. 18, 1998 3857
Ta ble 1. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
[(OEP)Os(NO)]2(µ-O)‚2HCl (OEP)Os(NS)Cl
(OEP)Os(NS)Me
formula
C
72H90N10O3Cl2Os2
C36H44N5ClSOs
C37H47N5SOs
fw
1594.84
804.47c
784.06
T, K
188(2)
173(2)
188(2)
triclinic
P1h
cryst syst
space group
unit cell dimens
tetragonal
monoclinic
P4/nnc
P21
a ) 13.8263(9) Å, R ) 90°
b ) 13.8263(9)Å, â ) 90°
c ) 17.342(2) Å, γ ) 90°
3315.2(5) Å3, 2
1.598
a ) 8.3150(11) Å, R ) 90°
b ) 21.184(3) Å, â ) 103.459(9)°
c ) 10.8990(14) Å, γ ) 90°
1867.1(5) Å3, 2
1.431
a ) 8.631(2) Å, R ) 81.45(3)°
b ) 10.344(4) Å, â ) 67.73(2)°
c ) 10.504(4) Å, γ ) 68.92(2)°
809.7(5) Å3, 1
V, Z
D(calcd), g/cm3
abs coeff, mm-1
F(000)
1.608
3.966
1604
3.572
808
4.037
396
cryst size, mm
θ range for data
collection, deg
index ranges
0.18 × 0.38 × 0.22
0.40 × 0.32 × 0.03
0.12 × 0.34 × 0.19
1.88-24.99
1.92-25.04
2.10-25.00
0 e h e 16, -13 e k e 11,
-20 e l e 0
2375
1475 [R(int) ) 0.0389]
semiempirical from æ-scans
0.1412 and 0.0944
-9 e h e 9, -25 e k e 22,
0 e l e 12
9496
-9 e h e 0, -12 e k e 11,
-12 e l e 11
2986
2768 [R(int) ) 0.0213]
semiempirical from æ-scans
0.5263 and 0.3883
no. of reflns collected
no. of indep reflns
abs corr
5286 [R(int) ) 0.0256]
SADABS
max and min
1.000 and 0.540
transmission
data/restraints/params
goodness-of-fit on F2
final R indices
1474/0/110
5285/30/435
2763/1/195
1.053
1.049
1.087
R1 ) 0.0346, wR2 ) 0.0746
R1 ) 0.0334, wR2 ) 0.0871
R1 ) 0.0636, wR2 ) 0.1546
[I > 2σ(I)]a,b
R indices (all data)a,b
largest diff peak and
hole, e Å-3
R1 ) 0.0615, wR2 ) 0.0875
0.846 and -0.790
R1 ) 0.0348, wR2 ) 0.0900
1.868 and -1.046
R1 ) 0.0643, wR2 ) 0.1562
2.602 and -2.481
R1 ) ∑||Fo| - |Fc||/∑|Fo|. b wR2 ) {∑[w(Fo2 - Fc2)2]/∑[wFo4]}1/2
.
c The crystal contains an unidentified solvent molecule (see Experimental
a
Section).
meso-H of OEP), 5.28 (s, CH2Cl2), 4.20 (q, J ) 8, 16H, CH3CH2
of OEP), 2.03 (t, J ) 8, 24H, CH3CH2 of OEP). Low-resolution
mass spectrum (FAB): m/z 805 [(OEP)Os(NS)Cl]+ (58), 770
[(OEP)Os(NS)]+ (53). UV-vis spectrum (λ (ꢀ, mM-1 cm-1), 1.24
× 10-5 M in CH2Cl2): 362 (75), 385 (sh, 63), 605 (6) nm.
Attempts to obtain an elementally pure sample of this air-
sensitive sample have so far not been very successful. Anal.
Calcd for C36H44N5ClSOs‚0.9CH2Cl2: C, 50.31; H, 5.24; N, 7.95;
Cl, 11.27; S, 3.64. Found: C, 49.54; H, 5.13; N, 7.75; Cl, 10.84;
S, 3.71.
(OEP )Os(15NS)Cl. This compound was prepared similarly
to the unlabeled analogue (using (15NSCl)3). IR (KBr, cm-1):
15
υ
1231 s.
NS
Syn th esis of (OEP )Os(NS)Me. To a solution of (OEP)-
Os(NS)Cl (0.031 g, 0.038 mmol) in THF (10 mL) was added
MeMgBr (0.20 mL, 1.4 M in THF, 0.28 mmol) dropwise at room
temperature. The color of the solution changed from green to
brown-red, and the solvent was removed in vacuo immediately.
The resulting brown residue was dissolved in benzene and
chromatographed (under reduced laboratory lighting) under
nitrogen on an alumina column (2 × 60 cm) prepared in
hexane. Elution with a 1:1 mixture of benzene/hexane gave a
brown band, which was collected and taken to dryness to give
(OEP)Os(Me)2 (0.004 g, 14% isolated yield).
F igu r e 1. UV-vis spectra of [(OEP)Os(NO)]2(µ-O) (s),
(OEP)Os(NO)Me (- - -), and (OEP)Os(NO)Cl (‚‚‚) in CH2-
Cl2. [(OEP)Os- concentration of 7.81 × 10-6 M.]
A second light-green band was collected and taken to
dryness in vacuo to give (OEP)Os(NS)Me (0.007 g, 23% isolated
yield). IR (KBr, cm-1): υNS 1196 m; also 2966 s, 2930 m, 2869
w, 1470 w, 1444 w, 1372 w, 1317 w, 1272 m, 1226 w, 1151 m,
1111 w, 1055 m, 1020 s, 994 m, 963 m, 838 w, 745 m, 713 w.
1H NMR (CDCl3, δ): 10.30 (s, 4H, meso-H of OEP), 4.14 (m,
16H, CH2CH3 of OEP), 1.97 (t, J ) 8, 24H, CH2CH3 of OEP),
-7.88 (s, 3H, CH3). UV-vis spectrum (λ, CH2Cl2): 372 (100,
Soret), 433 (br sh, 26), 585 (br sh, 12) nm.
Os(CO), see above) for a single-crystal X-ray structural deter-
mination was grown by slow solvent evaporation from satu-
rated CH2Cl2 solution under nitrogen for 3 days. The crystal
data were collected on a Siemens P4 diffractometer. The data
were corrected for Lorentz and polarization effects, and an
empirical absorption correction based on ψ-scans was applied.
The structure was solved by the direct method using the
SHELXTL (Siemens) system and refined by full-matrix least-
squares based on F2 using all reflections. The hydrogen atom
of the HCl molecule (H1) was located in the difference map
and refined isotropically. All the other hydrogen atoms were
included with idealized parameters. The unit cell contains two
[(OEP)Os(NO)]2(µ-O) and four HCl molecules, and they pack
along the 4-fold axis in alternate layers of hydrogen-bonded
HCl and [(OEP)Os(NO)]2(µ-O) molecules as shown in Figure
(OEP )Os(15NS)Me. This compound was prepared similarly
to the unlabeled analogue. IR (KBr, cm-1): υ
1163.
15
NS
Solid -Sta te Str u ctu r a l Deter m in a tion s. Details of crys-
tal data and refinement are given in Table 1. The crystal data
were collected using Mo KR (λ ) 0.710 73 Å) radiation.
(i) [(OEP )Os(NO)]2(µ-O)‚2HCl. A suitable crystal of the
compound (obtained from the reaction of ClNO with (OEP)-

3858 Organometallics, Vol. 17, No. 18, 1998
Cheng et al.
F igu r e 2. Molecular structure of [(OEP)Os(NO)]2(µ-O)
showing 30% ellipsoids. Hydrogen atoms have been omitted
for clarity.
4a.57 There are actually eight sites of the HCl molecule in the
unit cell, with each site occupied only 50%, thus generating a
total of four HCl molecules. The [(OEP)Os(NO)]2(µ-O) mol-
ecule has a very high crystallographically imposed symmetry
with only one-eighth of the molecule being unique. Several
atoms are situated at special symmetry sites. The O2 atom
has the highest point symmetry and is located at special
position a 42 symmetry point. The Os1, O1, and N2 atoms
lie along the 4-fold symmetry axis, and the Cl1 and H1 atoms
also lie along the 2-fold axis. For the HCl molecule, the sites
are occupied only 50% and both the Cl1 and H1 atoms were
refined with a 0.25 occupancy factor instead of 0.5, which is
required for these special positions.
(ii) (OEP )Os(NS)Cl. A suitable crystal for structural
determination was grown by slow solvent evaporation from
the CH2Cl2 solution in a drybox. The single-crystal X-ray
structural analysis was performed at the University of Min-
nesota. The crystal data were collected on a Siemens SMART
Platform CCD instrument. The space group was determined
based on systematic absences and intensity statistics.
A
successful direct-methods solution was calculated which pro-
vided most non-hydrogen atoms from the E-map. Several full-
F igu r e 3. (a) Perpendicular atom displacements (in units
of 0.01 Å) of the porphyrin core from the 24-atom mean
porphyrin plane. Positive values are toward the axial NO
ligand. (b) View of the porphyrin core orientations relative
to each other, with the view along the Os-Os direction.
(57) One reviewer suggested that the Cl atoms could be from CH2-
Cl2 molecules, which would be consistent with the observed Cl‚‚‚Cl
distance of 2.85 Å. The reviewer also suggested that HCl (strong acid)
might not be expected to coexist with the µ-oxo dimer in the same
crystal. We checked these points by reexamination of the crystal-
lography (a) and by chemical means (b). (a) It seems highly unlikely
that CH2Cl2 is present, since the close proximity of the 4-fold symmetry
axis will generate eight possible Cl-atom sites rather than the four
which were observed. A close reexamination of the difference map
shows absolutely no indication of the presence of a carbon atom, even
at fractional occupancy. We feel that the presence of HCl in the lattice
as described is consistent with the observed data. (b) Interestingly,
HCl (which was present in the ClNO solution used to form the mixture
of (OEP)Os(NO)Cl and [(OEP)Os(NO)]2(µ-O)) reacts only very slowly
with the oxo dimer in CH2Cl2, even at room temperature under
nitrogen. For example, stirring a 1:3 mixture of the oxo dimer and HCl‚
Et2O (Aldrich) over a 23 h period results in no observable reaction (as
determined by UV-vis spectroscopy). A further examination of the
reaction solution by TLC (silica gel) in air revealed only trace formation
of (OEP)Os(NO)Cl. Reaction of [(OEP)Os(NO)]2(µ-O) with 10 equiv of
HCl‚Et2O for 1 h results in a very small red shift of the peaks in the
UV-vis spectrum. However, only [(OEP)Os(NO)]2(µ-O) is recovered
after removal of the solvent and washing the resulting residue with
hexane, indicating lack of formation of (OEP)Os(NO)Cl. Reaction of
this 1:10 mixture for 18 h, however, results in ca. 40% conversion to
(OEP)Os(NO)Cl. In summary, we note that under our crystallization
conditions, the reaction of [(OEP)Os(NO)]2(µ-O) with 2-6 equiv of HCl
is slow enough to allow HCl and the oxo dimer to coexist in the same
crystal. It thus appears that the two axial π-acid NO ligands are able
to withdraw sufficient electron density from the µ-oxo bridge to render
it less reactive to HCl than would otherwise have been expected.
matrix least-squares/difference Fourier cycles were performed,
which located the remainder of the non-hydrogen atoms. All
non-hydrogen atoms were refined with anisotropic displace-
ment parameters. All hydrogen atoms were placed in ideal
positions and refined as riding atoms with relative isotropic
displacement parameters. The structure was as expected, but
the axial Cl and NS ligands are disordered in a 0.81:0.19 ratio.
The space group is P21 and appears to have a minor inversion
twin component in
a 0.91:0.09 ratio. Early work found
disordered solvent occupying 230.7 Å3 out of a unit cell volume
of 1867.1 Å3 or 12.3% of the total. PLATON58/SQUEEZE was
used to correct the data for the effects of disordered solvent.
Residuals improved about 1% while identifying 99 electrons
worth of scattering in this void. It is very likely that this
solvent is hexane, but the smeared-out positions made this
impossible to refine. Thus, the stated empirical formula, F000
,
formula weight, absorption coefficient, etc., should be taken
with caution since no solvent was taken into consideration in
their calculation. Finally, the axial Cl/NS disorder forced the
use of several positional and anisotropic displacement param-
(58) Spek, A. L. Acta Crystallogr. 1990, A46, C34.

Synthesis of Osmium Nitrosyl Porphyrins
Organometallics, Vol. 17, No. 18, 1998 3859
crystal data were collected on a Siemens P4 diffractometer.
The data were corrected for Lorentz and polarization effects,
and an empirical absorption correction based on ψ-scans was
applied. The structure was solved by the heavy-atom method
using the SHELXTL (Siemens) system and refined by full-
matrix least-squares based on F2 using all reflections. Hy-
drogen atoms were included with idealized parameters. Hy-
drogen atoms were not included for C37A, which was affected
by disorder. The molecule has rigorous crystallographic
inversion symmetry, hence the asymmetric unit contains only
one-half of the unique molecule. The Os atom lies at the center
of symmetry. Because of the crystallographic symmetry
requirement, the axial methyl (C37A or C37) and NS (N3 and
S1) groups are completely disordered. Attempts to refine C37
and N3 with slightly different positional parameters yielded
poor and unstable refinement. Finally, C37 and N3 were
assigned identical positional and thermal parameters, which
gave a more stable refinement. All the non-hydrogen atoms
were refined anisotropically except C37, N3, and S1 (the atoms
affected by the disorder), which were refined isotropically. The
sulfur atom was also refined anisotropically and did not show
any alternate sulfur-atom position. There are several large
peaks in the vicinity, but none of them are consistent with an
alternate sulfur-atom position. We feel that the large thermal
parameter for the sulfur atom is due to the general disorder,
and because of the limitations of the data and the disorder
problem, it is appropriate to refine it isotropically. The
possibility of NO contamination is also ruled out on the basis
of chemical evidence.
The structure was also solved and refined in the P1 (No. 1)
alternate space group, since it will not have the disordered
methyl and NS groups. However, it always gave peaks of the
NS group on both sides of the porphyrin plane and gave
extremely poor and unstable refinement. Therefore, the choice
of P1h space group was deemed to be correct. In addition to
the disorder, the overall quality of the data and refinement is
limited (slightly large R factor and residual peaks in the
difference map) due to poor quality crystals. All the crystals
obtained from different crystallization methods were extremely
fragile and unstable. Repeated attempts to grow better quality
crystals were unsuccessful.
Resu lts a n d Discu ssion
The organometallic (OEP)Os(NO)R complexes are
formed from the reaction of (OEP)Os(CO) with NOPF6
in CH2Cl2, followed by reaction of the [(OEP)Os(NO)]-
PF6 intermediate with RMgX (X ) Cl, Br) in THF.
Although the (OEP)Os(NO)R complexes were the initial
target products, we found that other nitrosyl and non-
nitrosyl products were also formed in this reaction of
[(OEP)Os(NO)]PF6 with Grignard reagents.59 The gen-
eral reaction is shown in Scheme 1.
The initial reaction to produce [(OEP)Os(NO)]PF6 is
performed in CH2Cl2 at room temperature under re-
duced laboratory lighting (see later) with the rigorous
exclusion of air and moisture to avoid the formation of
the (OEP)Os(NO)(O2PF2) hydrolysis product.60 The
Grignard reaction is performed in THF, and the progress
of the reaction is monitored by TLC (silica gel) using a
1:1 benzene/hexane mixture in air.
F igu r e 4. (a) View of the unit cell containing [(OEP)Os-
(NO)]2(µ-O)‚2HCl. (b) View of the alternate pairs of HCl
molecules showing the H-bond interactions.
eter restraints. Thirty restraints (SHELXTL SAME/SADI/
ISOR) were applied to these atoms and to N1/C1. N1/C1 had
uncharacteristic elongated thermal ellipsoids normal to the
porphyrin ring. The anisotropic displacement parameters for
C1 were nonpositive definite without the restraint. Least-
squares correlations were checked for these atoms, but none
involving these atoms were found.
(iii) (OEP )Os(NS)Me. A suitable crystal of (OEP)Os(NS)-
(Me) for structural determination was grown by slow solvent
evaporation from a CH2Cl2 solution under nitrogen. The
The products (Scheme 1) are then separated by
column chromatography on neutral alumina using a 1:1
(59) The reaction of RMgX with non-nitrosyl osmium- and other
metalloporphyrin cations to produce organometallic derivatives has
some precedent, see: (a) Reference 43. (b) Ogoshi, H.; Sugimoto, H.;
Yoshida, Z.-I.; Kobayashi, H.; Sakai, H.; Maeda, Y. J . Organomet.
Chem. 1982, 234, 185-195.
(60) Chen, L.; Khan, M. A.; Richter-Addo, G. B. Inorg. Chem. 1998,
37, 533-540.

3860 Organometallics, Vol. 17, No. 18, 1998
Cheng et al.
notation61 and are expected to have linear Os-NO
linkages. Although we have not been able to grow
suitable crystals of any of these organoosmium nitrosyls
for an X-ray diffraction study, we note that the υNO
range in the IR spectra of these complexes (1703-1748
Sch em e 1
cm-1) is lower than those for (OEP)Os(NO)(S-i-C5H11
)
(1757 cm-1) and (OEP)Os(NO)(O-n-Bu) (1757 cm-1) but
are substantially lower than that displayed for the
cationic Os-NO center in (OEP)Os(NO)(O2PF2) (1820
cm-1). Several of these latter (OEP)Os(NO)-containing
derivatives display linear Os-NO fragments in their
solid-state structures.60
The IR υNO of these compounds decrease in the order
(OEP)Os(NO)(p-C6H4F) (1748 cm-1) > (OEP)Os(NO)-
Me (1720 cm-1) > (OEP)Os(NO)Et (1710 cm-1) >
(OEP)Os(NO)(iPr) (1703 cm-1) ≈ (OEP)Os(NO)(tBu)
(1703 cm-1) and generally reflects the electron-donating
abilities of the R ligands and the ability of the trans
π-acid NO ligand to effectively withdraw additional
electron density from the metal center in these com-
plexes. The υNO of the tetraarylporphyrin (TTP)Os(NO)-
Me complex is at 1729 cm-1 and reflects the fact that
the (TTP)Os fragment is less electron rich than the
(OEP)Os fragment.62
benzene/hexane mixture as eluent. The (OEP)Os(R)2
compound is eluted first followed by the (OEP)Os(NO)R
nitrosyl compound. The (OEP)Os(NO)X nitrosyl halide
is eluted next with CH2Cl2/hexane, and finally the
[(OEP)Os(NO)]2(µ-O) oxo dimer is eluted with THF/
hexane. The chromatography is performed under re-
duced lighting to minimize the decomposition of the
nitrosyl alkyl/aryl products. The nitrosyl compounds
The 1H NMR spectra of these (OEP)Os(NO)R com-
plexes are consistent with their formulation. In an
excellent review on cis- and trans-effects/influences in
metalloporphyrins, Buchler has shown that the δmeso
peak in (OEP)Os complexes is a measure of the overall
back-bonding ability of the Os center to the porphyrin.62
In general, a more electron-rich Os center will result in
an upfield shift of δmeso. The δmeso peaks (of the OEP
macrocycle) in these (OEP)Os(NO)R complexes fall
within the narrow 10.21-10.24 ppm range, although
significant changes are observed in υNO. Consequently,
and not unexpectedly, it appears that the trans-influ-
ence involving the axial ligand interactions is larger
than the cis-influence in the (OEP)Os(NO)R complexes.
Indeed, our observation that the δmeso peaks for the non-
nitrosyl (OEP)Os(R)2 complexes decrease significantly
in the order (OEP)Os(p-C6H4F)2 (9.71 ppm) > (OEP)-
Os(Me)2 (9.34 ppm) > (OEP)Os(Et)2 (9.23 ppm) > (OEP)-
Os(tBu)2 (9.03 ppm) emphasizes this point. Not sur-
prisingly, therefore, the δmeso peaks of the (OEP)Os(NO)R
complexes lie downfield from those of the corresponding
(OEP)Os(R)2 complexes, since the π-acid nitrosyl ligand
is an effective withdrawer of electron density from the
Os center. Interestingly, the proton resonances for the
axial R-H’s in the (OEP)Os(NO)R complexes are shifted
significantly upfield from those in the non-nitrosyl
(OEP)Os(R)2 complexes. For example, the axial R-H
resonance for (OEP)Os(NO)Me is at -8.10 ppm while
that for (OEP)Os(Me)2 is at -1.16 ppm. The same trend
is observed for the axial R-H resonance of (OEP)Os(NO)-
Et at -7.45 ppm (CH2Me), compared with that of (OEP)-
Os(Et)2 at -0.72 ppm (CH2Me). We are cautious not to
over-interpret these trends, however, since many more
factors need to be taken into consideration when dealing
with the rather complicated metalloporphyrin macro-
cycle and associated cis- and trans-influences.62
1
have been characterized by IR and H NMR spectros-
copy, FAB mass spectrometry, and by elemental analy-
ses. They have also been characterized by UV-vis
spectroscopy, and representative spectra are shown in
Figure 1.
The formation of the (OEP)Os(R)2 compound probably
arises from further reaction of (OEP)Os(NO)R with
RMgX. Indeed, the reaction of a pure sample of (OEP)-
Os(NO)(p-C6H4F) with excess (p-C6H4F)MgBr for 2 h
results in a 20% conversion of the nitrosyl compound
to the non-nitrosyl (OEP)Os(p-C6H4F)2 derivative (50%
conversion after 24 h). A similar nitrosyl-for-alkyl
substitution has been noted for the analogous (TTP)-
Ru(NO)(p-C6H4F) compound.44 The formation of (OEP)-
Os(NO)X from RMgX was unexpected, however, since
the reaction of [(OEP)Os(NO)]PF6 with MgCl2 or KBr
under refluxing conditions in THF does not, at least in
our hands, produce the (OEP)Os(NO)X compounds. The
novel [(OEP)Os(NO)]2(µ-O) oxo dimer product probably
arises from some (OEP)Os(CO)(H2O) or from adventi-
tious air and moisture during the reaction and isolation
procedures. Indeed, a quantitative conversion of (OEP)-
Os(NO)(tBu) to [(OEP)Os(NO)]2(µ-O) occurs within 45
min (as monitored by UV-vis spectroscopy) when a
CH2Cl2 solution of an authentic sample of (OEP)Os-
(NO)(tBu) is exposed to air.
Nitr osyl Alk yl/Ar yl Com p lexes. The red (OEP)-
Os(NO)R complexes are isolated in 5-44% yields de-
pending on the reaction conditions and the nature of R.
The nitrosyl products appear to be moderately stable
in air as solids for short periods (hours). However, their
solutions are sensitive to air and moisture and to
laboratory lighting: their benzene solutions being more
stable than their CH2Cl2 solutions. In general, the
observed order of stability of these nitrosyl products is
(OEP)Os(NO)Me > (OEP)Os(NO)Et > (OEP)Os(NO)(i-
Pr) > (OEP)Os(NO)(tBu).
(61) Feltham, R. D.; Enemark, J . H. Top. Stereochem. 1981, 12, 155-
215.
(62) Buchler, J . W.; Kokisch, W.; Smith, P. D. Struct. Bonding 1978,
34, 79-134.
These (OEP)Os(NO)R compounds are of the {Os-
(NO)}6 formulation according to the Enemark-Feltham

Synthesis of Osmium Nitrosyl Porphyrins
Organometallics, Vol. 17, No. 18, 1998 3861
Ta ble 2. Selected Bon d Len gth s a n d An gles for
Nitr osyl Ha lid e Com p lexes. As shown in Scheme
1, the (OEP)Os(NO)Cl and (OEP)Os(NO)Br complexes
are also formed from the low-temperature reactions of
[(OEP)Os(NO)]PF6 with RMgCl and RMgBr, respec-
tively. In some cases (e.g., the reaction with MeMgBr
at low temperature), they are the major isolated prod-
ucts. At room temperature, however, the (OEP)Os-
(NO)X complexes may also react with RMgX to form
(OEP)Os(NO)R. For example, the reaction of (OEP)-
Os(NO)Br with excess (p-C6H4F)MgBr in THF for 0.5 h
gives a 1:1 mixture of (OEP)Os(NO)(p-C6H4F) and
(OEP)Os(p-C6H4F)2. To the best of our knowledge, these
nitrosyl halide compounds have not been reported
previously in the literature, although the (OEP)Os-
(NO)F complex has been known for over 20 years.63,64
Interestingly, this latter fluoride compound is obtained
in 14% yield if (OEP)Os(CO) is reacted with a 2-fold
excess of NOPF6 under laboratory lighting. A higher
yield of (OEP)Os(NO)F (92%) is obtained from the
reaction of (OEP)Os(NO)Cl with excess AgBF4 in tolu-
ene for 0.5 h. In any event, these (OEP)Os(NO)X (X )
F, Cl, Br) compounds are air-stable, showing no signs
of decomposition in the solid-state or in solution in air
overnight.
[(OEP )Os(NO)]2(µ-O)‚2HCl
Bond Lengths (Å)
Os(1)-N(1)
Os(1)-N(2)
2.066(5)
1.778(11)
Os(1)-O(2)
N(2)-O(1)
2.0945(5)
1.143(13)
Bond Angles (deg)
Os(1)-N(2)-O(1)
Os(1)-O(2)-Os(2)
N(1)-Os(1)-O(2)
180.0
180.0
85.8(2)
N(1)-Os(1)-N(2)
N(2)-Os(1)-O(2)
94.2(2)
180.0
are given in Table 2. To the best of our knowledge, this
is the first reported example of a nitrosyl porphyrin
µ-oxo dimer of any metal (Table 3). The Os-N(porphy-
rin) bond length of 2.066(5) Å is within the 1.986(9)-
2.109(8) Å range observed for other (OEP)OsII porphy-
rins.65 The Os-N(2) and N(2)-O(1) bond lengths of
1.778(11) and 1.143(13) Å are typical for osmium ni-
trosyls.65 The Os-N-O moiety is linear. The Os-(µ-
oxo)-Os group is also linear, with an Os-O(2) bond
length of 2.0945(5) Å.
The porphyrin core is domed, and the Os atom is
displaced 0.23 Å from the 24-atom mean plane toward
the axial NO ligand (Figure 3a). This observed Os
displacement is indeed remarkable, since a common
feature of porphyrin µ-oxo dimers is the displacement
of the metal toward the µ-oxo bridge.80 For example,
the Os atom is found to be displaced 0.07 Å from the
24-atom porphyrin core toward the µ-oxo ligand in the
only other structurally characterized osmium porphyrin
µ-oxo complex, namely [(OEP)Os(OCH3)]2(µ-oxo).79,80
The two porphyrin rings in [(OEP)Os(NO)]2(µ-O) display
a twist angle of 22.5° with respect to each other (Figure
3b).
As expected, the υNO of these (OEP)Os(NO)X com-
plexes (1799-1795 cm-1) are higher than those of the
(OEP)Os(NO)R complexes mentioned in the earlier
1
section. Furthermore, the δmeso peaks in the H NMR
spectra of the (OEP)Os(NO)X complexes (10.40-10.41
ppm) are shifted downfield from those of the (OEP)Os-
(NO)R complexes (10.21-10.23 ppm).
Nitr osyl Oxo Dim er . We were intrigued with our
observation of a fourth isolable product from the reac-
tion described in Scheme 1. The IR spectrum of this
complex revealed a band at 1770 cm-1 in CH2Cl2
attributable to υNO. This υNO is lower than that of the
(OEP)Os(NO)X halide complexes just described but is
much higher than those of the (OEP)Os(NO)R com-
plexes. However, it is slightly higher than those of
(OEP)Os(NO)(O-n-Bu) (1757 cm-1) and (OEP)Os(NO)-
(O-i-C5H11) (1756 cm-1) but lower than that of
(OEP)Os(NO)(O2PF2) (1820 cm-1),60 all of which contain
The crystal also contains HCl as a solvate.57 The close
proximity of the HCl molecule to the 4-fold symmetry
axis generates a set of four molecules with Cl‚‚‚Cl
distances of 2.02 and 2.85 Å (Figure 4a). The Cl‚‚‚Cl
distance of 2.02 Å is too short to be real and can be
explained by the partial occupancy of these sites. The
(65) See Tables 2 and 3 in ref 60 for
a listing of structurally
characterized osmium nitrosyls and porphyrins.
(66) Chen, B.; Hobbs, J . D.; Debrunner, P. G.; Erlebacher, J .;
Shelnutt, J . A.; Scheidt, W. R. Inorg. Chem. 1995, 34, 102-110.
(67) Swepston, P. N.; Ibers, J . A. Acta Crystallogr. 1985, C41, 671-
673.
1
axial O-bound ligands trans to NO. However, the H
NMR spectrum of this complex only showed resonances
due to the OEP macrocycle. The δmeso peak is at 10.35
ppm, which is between those of the (OEP)Os(NO)X
complexes (10.40-10.41 ppm) and the (OEP)Os(NO)R
compounds (10.21-10.24 ppm). Interestingly, this fourth
product (Scheme 1) is also obtained as a byproduct in
48% yield from our attempts to generate (OEP)Os(NO)-
Cl (obtained in 49% yield) from the reaction of (OEP)-
Os(CO) with ClNO in CH2Cl2. We were able to obtain
a suitable crystal of this complex as an HCl solvate by
slow evaporation of a CH2Cl2 solution of the crude
product (the source of HCl is probably the ClNO reagent,
since concentrated HCl was used in its preparation). The
identity of this [(OEP)Os(NO)]2(µ-O) complex was es-
tablished by a single-crystal X-ray crystallographic
analysis of a suitable crystal obtained from the latter
reaction.
(68) J iao, X.-D.; Huang, J .-W.; J i, L.-N.; Luo, B.-S.; Chen, L.-R. J .
Inorg. Biochem. 1997, 65, 229-233.
(69) Schaefer, W. P.; Ellis, P. E.; Lyons, J . E.; Shaikh, S. N. Acta
Crystallogr. 1995, C51, 2252-2255.
(70) Gold, A.; J ayaraj, K.; Doppelt, P.; Fischer, J .; Weiss, R. Inorg.
Chim. Acta 1988, 150, 177-181.
(71) Lay, K.-L.; Buchler, J . W.; Kenny, J . E.; Scheidt, W. R. Inorg.
Chim. Acta 1986, 123, 91-97.
(72) Strauss, S. H.; Pawlik, M. J .; Skowyra, J .; Kennedy, J . R.;
Anderson, O. P.; Spartalian, K.; Dye, J . L. Inorg. Chem. 1987, 26, 724-
730.
(73) Karlin, K. D.; Nanthakumar, A.; Fox, S.; Murthy, N. N.; Ravi,
N.; Huynh, B. H.; Orosz, R. D.; Day, E. P. J . Am. Chem. Soc. 1994,
116, 4753-4763.
(74) Landrum, J . T.; Grimmett, D.; Haller, K. J .; Scheidt, W. R.;
Reed, C. A. J . Am. Chem. Soc. 1981, 103, 2640-2650.
(75) Ivanca, M. A.; Lappin, A. G.; Scheidt, W. R. Inorg. Chem. 1991,
30, 711-718.
(76) Masuda, H.; Taga, T.; Osaki, K.; Sugimoto, H.; Mori, M.; Ogoshi,
H. J . Am. Chem. Soc. 1981, 103, 2199-2203.
(77) Masuda, H.; Taga, T.; Osaki, K.; Sugimoto, H.; Mori, M.; Ogoshi,
H. Bull. Chem. Soc. J pn. 1982, 55, 3887-3890.
(78) Collman, J . P.; Barnes, C. E.; Brothers, P. J .; Collins, T. J .;
Ozawa, T.; Galluci, J . C.; Ibers, J . A. J . Am. Chem. Soc. 1984, 106,
5151-5163.
(79) Masuda, H.; Taga, T.; Osaki, K.; Sugimoto, H.; Mori, M. Bull.
Chem. Soc. J pn. 1984, 57, 2345-2351.
(80) See Table 6 in ref 66 for an extensive and informative listing
of structural parameters for porphyrin µ-oxo dimers.
The molecular structure of [(OEP)Os(NO)]2(µ-O) is
shown in Figure 2, and selected bond lengths and angles
(63) Buchler, J .; Smith, P. D. Chem. Ber. 1976, 109, 1465-1476.
(64) Antipas, A.; Buchler, J . W.; Gouterman, M.; Smith, P. D. J .
Am. Chem. Soc. 1980, 102, 198-207.

3862 Organometallics, Vol. 17, No. 18, 1998
Ta ble 3. Selected Str u ctu r a l P a r a m eter s for Gr ou p 8 Oxo-Br id ged P or p h yr in Dim er s
Cheng et al.
compound
M-(µ-O), Å
M-O-M (deg)
ref
Iron
1.758(3)
1.754(3)
1.748(4)
1.762(4)
1.759(1)
1.743(3)
1.763(4)
1.751(4)
1.775(1)
1.752(1)
1.747(5)
1.763(5)
1.760(2)
1.800(6)
1.774(6)
1.750(2)
1.740(4)
1.767(4) (TPP)
[(OEP)Fe]2(µ-O) triclinic
172.2(2)
66
monoclinic
176.21(23)
[(TPP)Fe]2(µ-O)
[(T(p-Cl)PP)Fe]2(µ-O)
[(OEP(NO2)2)Fe]2(µ-O)
176.1
180.0
167.9(3)
67
68
69
[(T(F5)PP)Fe]2(µ-O)
[(Me2OEP)Fe]2(µ-O)
[(TPC)Fe]2(µ-O)a
178.4(5)
178.5(6)
180.0
70
71
72
[(T(o-F2)PP)Fe]2(µ-O)
[(FF)Fe]2(µ-O)b
178.5(8)
161.1(4)
73
74
[(TMPyP)Fe]2(µ-O)‚(ClO4)8
[(N-CH3TPP)Fe-O-Fe(TPP)]ClO4
175.1(7)
165.4(3)
75
20
Ruthenium
1.847(13)
1.793(2)
1.787(11)
1.791(11)
[(OEP)Ru(OH)]2(µ-O)
180.0
180.0
177.8(7)
76
77
78
[(OEP)Ru(Cl)]2(µ-O)
[(TPP)Ru(p-OC6H4Me)]2(µ-O)
Osmium
1.807(3)
[(OEP)Os(OCH3)]2(µ-O)
[(OEP)Os(NO)]2(µ-O)
177.4(17)
[179.5(11)]c
180.0
79
[1.809(3)]c
2.0945(5)
this work
a
b
TPC ) tetraphenylchlorinato dianion. FF ) face-to-face porphyrin. N,N-Bis(5-o-phenyl)-10,15,20-triphenylporphyrin urea. c Two
independent dimers. The values for the second dimer are in brackets.
Cl‚‚‚Cl distance of 2.85 Å is reasonable for a Cl-H‚‚‚Cl
hydrogen bond. A reasonable model for the four HCl
molecules is actually two pairs of hydrogen-bonded
molecules as shown in Figure 4b. The distances and
angles for this hydrogen bond are Cl1-H1 (1.06(5) Å),
Cl1‚‚‚H1# (1.95(5) Å), Cl1‚‚‚Cl1# (2.854(5) Å), and Cl1-
#
H1‚‚‚Cl1# (140(3)°) (where
indicates a symmetry
equivalent position (-0.5 - x, -0.5 - y, z). These
distances are consistent with the reported values for
other HCl solid-state structures.81-86 Partial occupancy
of the HCl molecule is not unusual.87
Th ion it r osyl Com p ou n d s. To the best of our
knowledge, no osmium porphyrin complex containing
the NS ligand has been reported, although the related
(TTP)Ru(NS)Cl compound is known88 and the (TPP)-
Fe(NS) compound claimed.53
F igu r e 5. Molecular structure of (OEP)Os(NS)Cl. Only the
highest occupancy axial Cl-Os-NS orientation is shown.
The (OEP)Os(NS)Cl compound is prepared in 49%
isolated yield from the reaction of (NSCl)3 with (OEP)-
Os(CO) in THF. The IR spectrum of this compound (as
a KBr pellet) reveals a band at 1270 cm-1 assigned to
1
confirming this assignment of υNS. The δmeso in the H
NMR spectrum of (OEP)Os(NS)Cl is at 10.49 ppm,
which is downfield from that of the nitrosyl (OEP)Os-
(NO)Cl analogue at 10.41 ppm.
υ
NS. This value is within the 1065-1390 cm-1 range
observed for other thionitrosyl compounds with linear
metal-NS linkages.89 Furthermore, the use of (15-
NSCl)3 in the preparation gives the analogous (OEP)-
We were able to obtain a suitable crystal for an X-ray
diffraction study. The molecular structure is shown in
Figure 5, and selected bond lengths and angles are given
in Table 4. The Os-N(porphyrin) bond length is 2.065
Å (average) and also falls within the range observed for
other structurally characterized (OEP)OsII porphy-
rins.60,65 The NS and Cl fragments are disordered. The
Os-N(S) and (Os)N-S bond lengths are 1.83(1) and
1.50(1) Å, respectively, and are comparable to those of
other Os-NS complexes that have been structurally
characterized (Table 5). The linearity of the Os-N-S
linkage is indicated by an Os-N-S bond angle of 174°.
The geometry of the Os-NS moiety is thus reasonable
15
15
Os( NS)Cl with a υ
of 1231 cm-1 (∆υNS ) 39 cm-1),
NS
(81) Mootz, D.; Deeg, A. J . Am. Chem. Soc. 1992, 114, 5887-5888.
(82) Moynihan, K. J .; Boorman, P. M.; Ball, J . M.; Patel, V. D.; Kerr,
K. A. Acta Crystallogr. 1982, B38, 2258-2261.
(83) Stepien, A. Acta Crystallogr. 1977, B33, 2854-2857.
(84) Mootz, D.; Hocken, J . Angew. Chem., Int. Ed. Engl. 1989, 28,
1697-1698.
(85) Mootz, D.; Deeg, A. Z. Anorg. Allg. Chem. 1992, 615, 109-113.
(86) Deeg, A.; Mootz, D. Z. Naturforsch. 1993, 48B, 571-576.
(87) Boorman, P. M.; Moynihan, K. J .; Richardson, J . F. Inorg. Chem.
1988, 27, 3207-3211.
(88) Bohle, D. S.; Hung, C.-H.; Powell, A. K.; Smith, B. D.; Wocadlo,
S. Inorg. Chem. 1997, 36, 1992-1993.
(89) Chivers, T.; Edelmann, F. Polyhedron 1986, 5, 1661-1699.

Synthesis of Osmium Nitrosyl Porphyrins
Ta ble 4. Selected Bon d Len gth s a n d An gles for (OEP )Os(NS)Cla
Bond Lengths (Å)
Organometallics, Vol. 17, No. 18, 1998 3863
Os(1)-N(5)
1.832(13) [1.834(13)]
Os(1)-N(2)
Os(1)-N(3)
Os(1)-N(4)
2.072(6)
2.075(9)
2.063(5)
N(5)-S(1)
1.501(12) [1.502(12)]
2.329(3) [2.327(4)]
2.050(7)
Os(1)-Cl(1)
Os(1)-N(1)
Bond Angles (deg)
Os(1)-N(5)-S(1)
Cl(1)-Os(1)-N(5)
N(1)-Os(1)-N(5)
N(1)-Os(1)-Cl(1)
N(1)-Os(1)-N(2)
N(1)-Os(1)-N(3)
N(1)-Os(1)-N(4)
N(2)-Os(1)-N(5)
174.5(14) [174(2)]
177.7(7) [176.4(10)]
92.1(6) [84.2(12)]
89.7(3) [92.4(7)]
90.2(3)
176.3(4)
89.8(2)
91.6(7) [88(2)]
N(2)-Os(1)-Cl(1)
N(2)-Os(1)-N(3)
N(2)-Os(1)-N(4)
N(3)-Os(1)-N(5)
N(3)-Os(1)-Cl(1)
N(3)-Os(1)-N(4)
N(4)-Os(1)-N(5)
N(4)-Os(1)-Cl(1)
90.0(2) [90.4(8)]
90.2(3)
176.4(2)
91.6(7) [92.1(11)]
86.7(2) [91.2(7)]
89.6(3)
92.1(7) [88(2)]
86.4(2) [93.3(8)]
a
Numbers in square brackets are for the minor (19%) disordered Cl(1′)-Os(1)-N(5′)-S(1′) component.
Ta ble 5. Selected Str u ctu r a l Da ta for Gr ou p 8 Th ion itr osyl Com p lexesa
compound
M-N (Å)
Osmium
N-S (Å)
M-N-S (deg)
ref
Os(NS)Cl3(PPh3)2
1.779(9)
1.731(4)
1.828(8)
1.832(13)
1.503(10)
1.514(5)
1.46(1)
180.0(1)
174.9(3)
169.1(5)
174.5(14)
90
91
92
(PPh4)[Os(NS)Cl4(H2O)]
(AsPh4)[Os(NS)(NSCl)Cl4]b
(OEP)Os(NS)Clc
1.501(12)
this work
Ruthenium
(PPh4)[Ru(NS)Cl4(H2O)]
1.729(4)
1.752(6)
1.69(3)
1.768(4)
[1.85(3)]
1.504(4)
1.466(7)
1.51(3)
1.489(5)
[1.47(3)]
170.9(3)
177.3(5)
175(2)
169.1(3)
[170(3)]
93
94
95
88
(PPh4)2[Ru(NS)Cl4]2‚4CH2Cl2
(PPh4)2[{Ru(NS)Br4}2(µ-N2S2)]‚4CH2X2
(TTP)Ru(NS)Cle
d
a
The data for (OEP)Os(NS)Me (this work) are not included because of the nature of the disorder, which precludes comparisons with
other M-NS complexes. The Cl atom of NSCl is disordered over the NS and NSCl ligands. c Data are for the 81% occupancy component.
b
Contains CH2Cl2 and CH2Br2 molecules (i.e., X ) Cl, Br). e Two independent molecules. Data for the second (disordered) molecule are
d
given in brackets and were obtained from the Supporting Information via the Internet.
(Table 5). Importantly, the M-N(S) bond lengths for
other (nongroup 8) metal thionitrosyl complexes range
from 1.694(2) (M ) Cr)96 to 1.87(2) Å (M ) Re).97 MN-S
bond lengths for these nongroup 8 compounds range
from 1.38(2) (M ) Re)98 to 1.592(11) Å (M ) Mo),99
whereas M-N-S bond angles range from 170.0(4)° (M
) Tc)100 to 179.9(1)° (M ) Tc).101
The spectroscopically pure (OEP)Os(NS)Me com-
pound is generated in 23% yield from the reaction of
(OEP)Os(NS)Cl with MeMgBr in THF. We have not
been able to obtain sizable amounts of a pure sample of
this compound for a satisfactory combustion analysis.
This compound is light and air sensitive and is also very
difficult to separate from the (OEP)Os(Me)2 byproduct
F igu r e 6. Molecular structure of (OEP)Os(NS)Me. Only
one of the two disordered axial SN-Os-Me orientations
is shown.
(also obtained in 14% yield). In any event, the υNS of
(OEP)Os(NS)Me is at 1196 cm-1 (υ
) 1163 cm-1),
15NS
(90) Roesky, H. W.; Pandey, K. K.; Clegg, W.; Noltemeyer, M.;
Sheldrick, G. M. J . Chem. Soc., Dalton Trans. 1984, 719-721.
(91) Pandey, K. K.; Roesky, H. W.; Noltemeyer, M.; Sheldrick, G.
M. Z. Naturforsch. 1984, 39b, 590-593.
reflecting the electron-donating nature of the axial
methyl group compared with the precursor chloride. The
1
δmeso in the H NMR spectrum of the (OEP)Os(NS)Me
(92) Weber, R.; Mu¨ller, U.; Dehnicke, K. Z. Anorg. Allg. Chem. 1983,
504, 13-22.
compound is at 10.30 ppm, which is shifted upfield by
0.19 ppm from that of the chloro (OEP)Os(NS)Cl pre-
cursor (at 10.49 ppm) but is shifted downfield from that
of its nitrosyl (OEP)Os(NO)Me analogue (at 10.21 ppm).
Interestingly, the δmeso peak of (OEP)Os(NO)Me is also
shifted (by 0.20 ppm) upfield from that of its chloro
precursor. Attempts to generate other (OEP)Os(NS)R
compounds have not yet been successful, and other
routes are being sought for their syntheses.
The molecular structure of (OEP)Os(NS)Me is shown
in Figure 6, and selected bond lengths and angles are
given in Table 6. The most important feature is the
confirmation of the identities of the trans methyl and
thionitrosyl ligands. The Os-N(porphyrin) bond lengths
(93) Bats, J . W.; Pandey, K. K.; Roesky, H. W. J . Chem. Soc., Dalton
Trans. 1984, 2081-2083.
(94) Willing, W.; Mu¨ller, U.; Demant, U.; Dehnicke, K. Z. Natur-
forsch. 1986, 41b, 560-566.
(95) Demant, U.; Willing, W.; Mu¨ller, U.; Dehnicke, K. Z. Anorg.
Allg. Chem. 1986, 532, 175-183.
(96) Greenhough, T. J .; Kolthammer, B. W. S.; Legzdins, P.; Trotter,
J . Inorg. Chem. 1979, 18, 3548-3554.
(97) Ruf, C.; Behrens, U.; Lork, E.; Mews, R. Chem. Commun. 1996,
939-940.
(98) Hauck, H.-G.; Willing, W.; Mu¨ller, U.; Dehnicke, K. Z. Natur-
forsch. 1986, 41b, 825-830.
(99) Hursthouse, M. B.; Motevalli, M. J . Chem. Soc., Dalton Trans.
1979, 1362-1366.
(100) Lu, J .; Clarke, M. J . J . Chem. Soc., Dalton Trans. 1992, 1243-
1248.
(101) Kaden, L.; Lorenz, B.; Kirmse, R.; Stach, J .; Behm, H.;
Beurskens, P. T.; Abram, U. Inorg. Chim. Acta 1990, 169, 43-48.

3864 Organometallics, Vol. 17, No. 18, 1998
Cheng et al.
Ta ble 6. Selected Bon d Len gth s a n d An gles for
(OEP )Os(NS)Mea
mium bis-alkyl/aryl porphyrins. We have also reported
the synthesis and structural characterization of a novel
osmium nitrosyl µ-oxo dimer. Studies are currently
underway to exploit the nature and reactivity of the
metal-carbon bond in these and related complexes.
Bond Lengths (Å)
Os(1)-N(3)
N(3)-S(1)
Os(1)-C(37A)
1.999(8)
1.433(13)
1.999(8)
Os(1)-N(1)
Os(1)-N(2)
2.056(7)
2.055(7)
Bond Angles (deg)
163.0(8) N(1)-Os(1)-N(2)
Ack n ow led gm en t. We are grateful to the National
Institutes of Health (FIRST Award 1R29 GM53586-
01A1) and the National Science Foundation (CAREER
Award CHE-9625065) for funding of this research. We
thank Dr. J . W. Buchler (Germany) for helpful discus-
sions. We also thank S. J . Hodge for initial experiments
involving related (TTP)Os(NO)- and (TTP)Os(NS)-
containing systems.102
Os(1)-N(3)-S(1)
90.4(3)
C(37A)-Os(1)-N(3) 180.0
N(1)-Os(1)-N(3)
N(2)-Os(1)-C(37A) 89.6(3)
91.5(3) N(2)-Os(1)-N(3)
90.4(3)
N(1)-Os(1)-C(37A)
88.5(3)
a
The axial methyl (C37A or C37) and NS (N3 and S1) groups
are completely disordered, and attempts to refine C37 and N3 with
slightly different positional parameters yielded poor and unstable
refinement. The C37 and N3 atoms were assigned identical
positional and thermal parameters, which gave more stable
refinement.
Su p p or tin g In for m a tion Ava ila ble: Figures and tables
of crystal data, atomic coordinates, anisotropic displacement
parameters, bond lengths and angles, hydrogen coordinates
and isotropic displacement parameters, torsion angles, and
least-squares planes (40 pages). Ordering information is given
on any current masthead page.
are 2.056(7) and 2.055(7) Å. Unfortunately, the nature
of the axial disorder (see Experimental Section) pre-
cludes a comparison of the bond lengths and angles
involving these axial groups.
In summary, we have reported the synthesis and
characterization of a new series of (i) organoosmium
nitrosyl and thionitrosyl porphyrins, (ii) osmium nitrosyl
and thionitrosyl halide porphyrins, and (iii) organoos-
OM980197S
(102) Hodge, S. J . Ph.D. Dissertation, University of Oklahoma, 1998.