Planar platinum metallacyclynes containing one and two trialkyne pockets

Article abstract of DOI:10.1021/om9507437

Efficient syntheses and characterization of a platinum metallacyclyne containing one cyclic enyne pocket (3), the first dinuclear platinum metallacyclyne containing two cyclic enyne pockets (4), and 2,2′,6,6′-tetraethynyltolan (2) are reported. Syntheses of 3 and 4 employ bidentate phosphines or cis-platinum starting materials and high dilution techniques to effect high yields.

Full text of DOI:10.1021/om9507437

2582
Organometallics 1996, 15, 2582-2584
P la n a r P la tin u m Meta lla cyclyn es Con ta in in g On e a n d
Tw o Tr ia lk yn e P ock ets
J ohn D. Bradshaw, Li Guo, Claire A. Tessier,* and Wiley J . Youngs*
Department of Chemistry, The University of Akron, Akron, Ohio 44325-3601
Received September 18, 1995X
Sch em e 1
Summary: Efficient syntheses and characterization of a
platinum metallacyclyne containing one cyclic enyne
pocket (3), the first dinuclear platinum metallacyclyne
containing two cyclic enyne pockets (4), and 2,2′,6,6′-
tetraethynyltolan (2) are reported. Syntheses of 3 and
4 employ bidentate phosphines or cis-platinum starting
materials and high dilution techniques to effect high
yields.
Substituted phenylethynyl compounds1 and extended
rigid-rod structures containing transition-metal σ-bound
acetylides and diacetylides2 are being explored as pos-
sible candidates for nonlinear optical (NLO)2d,3 and
liquid-crystalline materials.2f,4 The d electrons of tran-
sition metals in these systems are polarizable and may
provide greater NLO activity. Transition-metal σ-bound
bis(acetylides) are numerous, including platinum com-
plexes that primarily exist as trans-substituted systems.
Some cis-substituted platinum systems have been
reported;2a,5,6 however, analogous cyclic structures have
not been explored. Ethynyl-substituted tolans such as
2,2′-diethynyltolan (1)7 and 2,2′,6,6′-tetraethynyltolan
(2) possess the geometry necessary to give planar
metallacycles when their di- and tetraanions are com-
plexed with square-planar transition metals. Delocal-
ization of electrons should be enhanced by the planarity
of transition-metal σ-bis(acetylide) cycles, and as delo-
calization increases NLO properties may be enhanced
as well.3a
Sch em e 2a
a
Reagents and conditions: (i) 1.5 equiv of Me3SiCtCH,
(PhCN)2PdCl2, PPh3, CuI, Et3N for 14 h heating to 75 °C; (ii)
KF, H2O, MeOH-THF (5:2) for 10 h; (iii) 5, (PhCN)2PdCl2,
PPh3, CuI in Et3N-THF (3:1) at 50 °C for 3 days; (iv) 6 equiv
of Me3SiCtCH, (PhCN)2PdCl2, PPh3, CuI in piperidine at 95
°C for 14 h; (v) 2 equiv of cis-[Et3P]2PtCl2, CuI in CH2Cl2-
(i-Pr)2NH (1:4).
We report herein the syntheses and characterization
of two platinum metallacyclynes (i.e., metallacycles
X Abstract published in Advance ACS Abstracts, May 1, 1996.
(1) (a) Kondo, K.; Yasuda, S.; Sakaguchi, T.; Miya, M. J . Chem. Soc.,
Chem. Commun. 1995, 55-56. (b) Wong, M. S.; Nicoud, J .-F. J . Chem.
Soc., Chem. Commun. 1994, 249-250.
(2) (a) Diederich, F.; Faust, R.; Gramlich, V.; Seiler, P. J . Chem.
Soc., Chem. Commun. 1994, 2045-2046. (b) Faust, R.; Diederich, F.;
Gramlich, V.; Seiler, P. Chem. Eur. J . 1995, 1(2), 111-117 (In Angew.
Chem., Int. Ed. Engl. 1995, 34(9)). (c) Hagihara, N.; Sonogashira, K.;
Takahashi, S. Adv. Polym. Sci. 1981, 41, 149-186. (d) Abe, A.;
Kimura, N.; Tabata, S. Macromolecules 1991, 24, 6238-6243. (e)
Sonogashira, K.; Fujikura, Y.; Yatake, T.; Toyoshima, N.; Takahashi,
S.; Hagihara, N. J . Organomet. Chem. 1978, 145, 101-108. (f)
Takahashi, S.; Takai, Y.; Morimoto, H.; Sonogashira, K. J . Chem. Soc.,
Chem. Commun. 1984, 3-5.
(3) (a) Marder, T. B.; Lesley, G.; Yuan, Z.; Fyfe, H. B.; Chow, P.;
Stringer, G.; J obe, I. R.; Taylor, N. J .; Williams, I. D.; Kurtz, S. K. In
Materials for Nonlinear Optics; Marder, S. R., Sohn, J . E., Stucky, G.
D., Eds.; ACS Symposium Series 455; American Chemical Society:
Washington, DC, 1991; Chapter 40. (b) Long, N. J . Angew. Chem.,
Int. Ed. Engl. 1995, 34, 21-38.
(4) Takahashi, S.; Takai, Y.; Morimoto, H.; Sonogashira, K. Mol.
Cryst. Liq. Cryst. 1982, 82, 139-43.
(5) (a) Bonamico, M.; Dessy, G.; Fares, V.; Russo, M. V.; Scaramuzza,
L. Cryst. Struct. Commun. 1977, 6, 39-44 and references therein. (b)
Furlani, A.; Licoccia, S.; Russo, M. V. J . Chem. Soc., Dalton Trans.
1984, 2197-2206.
(6) (a) Yamazaki, S.; Deeming, A. J . J . Chem. Soc., Dalton Trans.
1993, 3051-3057. (b) Berenguer, J . R.; Fornie´s, J .; Lalinde, E.;
Mart´ınez, F. J . Organomet. Chem. 1994, 470, C15-C18 and references
therein. (c) Berenguer, J . R.; Fornie´s, J .; Lalinde, E.; Mart´ın, A.;
Moreno, M. T. J . Chem. Soc., Dalton Trans. 1994, 3343-3348.
(7) Dierks, R.; Vollhardt, K. P. C. Angew. Chem., Int. Ed. Engl. 1986,
25, 266-268.
containing enyne units) with one and two cyclyne
pockets (3 and 4) and a tetradentate tetraethynyltolan
ligand (2) (Schemes 1 and 2). Compound 4 is the first
example of a double-pocket cyclyne of either an organic
or organometallic type. Two principles were applied in
the successful syntheses of 3 and 4: use of bidentate
bis-phosphines or cis-platinum starting materials to
inhibit isomerization of PtCl2(PR2R′)2 to trans species
and high-dilution conditions to favor formation of
smaller oligomers.
[Fdpp]Pt(Tba) (3; Scheme 1), where Tba denotes
tolan-2,2′-diacetylide, was prepared under high-dilution
conditions using 2,2′-diethynyltolan (1), bis(benzoni-
trile)platinum dichloride (predominantly cis with some
trans),8 1,1′-bis(diphenylphosphino)ferrocene (Fdpp, Al-
drich), and CuI (2.5%) in diisopropylamine under ni-
trogen. The reaction mixture was stirred for 6 days,
after which an 85% yield of 3 was isolated by column
(8) (a) Uchiyama, T.; Toshiyasu, Y.; Nakamura, Y.; Miwa, T.;
Kawaguchi, S. Bull. Chem. Soc. J pn. 1981, 54, 181-185. (b) Braun-
stein, P.; Bender, R.; J ud, J . In Inorganic Syntheses; Kaesz, H. D., Ed.;
Wiley: New York, 1989; Vol. 26, pp 345-346.
S0276-7333(95)00743-6 CCC: $12.00 © 1996 American Chemical Society

Communications
Organometallics, Vol. 15, No. 11, 1996 2583
chromatography on silica gel with 1:3 CH2Cl2-hexanes
as eluent.9,10
Synthesis of 2,2′,6,6′-tetraethynyltolan (2; Scheme 2)
takes advantage of increased activity of the iodo sub-
stituent over that of the bromo substituent in 2,6-
dibromoiodobenzene (5).11 This selectivity provides an
efficient means of constructing 2, and high yields for
each bond formation are observed.12
Bridging two platinum centers with 2,2′,6,6′-tetra-
ethynyltolan (2) was accomplished by reacting it with
cis-bis(triethylphosphine)platinum dichloride and CuI
(5.0%) in a mixture of 1:4 CH2Cl2:(i-Pr)2NH under
nitrogen. This highly dilute solution was stirred at
room temperature for 2 weeks. Removal of solvent,
workup, and chromatographic separation on silica gel
using CH2Cl2 as the eluent gave a 65.6% yield of
([Et3P]2Pt)2(Tta) (4; Tta denotes tolan-2,2′,6,6′-tet-
raacetylide).13
X-ray crystal structures of these compounds (Figures
1 and 2) confirm their high symmetry, with 3 and 4
crystallizing in space groups C2/c and I4h, respec-
F igu r e 1. Thermal ellipsoid drawing of [Fdpp]Pt(Tba) (3)
drawn at the 50% probability level. H atoms and 2 CH2-
Cl2 molecules are omitted for clarity. Selected bond
distances (Å) and angles (deg): Pt-P1 ) 2.319(1), Pt-C1
) 1.994(3), C1-C2 ) 1.197(4), C5-C5a ) 1.200(6), Fe-
C10 ) 2.001(3), Fe-C11 ) 2.021(3), Fe-C12 ) 2.053(3),
Fe-C13 ) 2.044(3), Fe-C14 ) 2.032(3), P1-C10 )
1.796(3), P1-C15 ) 1.833(3), P1-C21 ) 1.819(3); P1-Pt-
P1a ) 101.46(4), C1-Pt-C1a ) 82.9(2), Pt-P1-C10 )
119.98(9), Pt-C1-C2 ) 170.6(2), C1-C2-C3 ) 175.9(3),
C4-C5-C5a ) 178.0(2).
(9) Second-order AXX′ 13C NMR spectral lines were modeled with
the spin simulation portion of the computer program VNMR (version
5) based on LAOCOON, and LAME algorithms: VNMR version 5,
Varian Associates, 1995.
(10) Anal. Calcd for C52H36FeP2Pt (2 CH2Cl2 in crystal structure
lost on standing): C, 64.1; H, 3.7; P, 6.4. Found: C, 65.77; H, 4.05; P,
5.75. FDMS: m/e 486.5 (M2+), 973 (M+, 195Pt, 56Fe). 1H NMR (300
MHz): δ (vs CDCl3) 4.22 (d, 4H), 4.32 (s, 4H), 6.60 (d, 2H), 7.03 (m,
4H), 7.35 (t, 8H), 7.43 (t, 4H), 7.51 (dd, 2H), 7.88 (m, 8H); δ (vs CD2-
Cl2) 4.23 (m, 4H), 4.33 (m, 4H), 6.60 (m, 2H), 7.06 (m, 4H), 7.3-7.5
(overlapping m, 14H), 7.85 (m, 8H); δ (vs C6D6) 3.75 (t, 4H), 4.06 (q,
4H), 6.87 (td, 2H), 6.96 (td, 2H), 7.0-7.1 (overlapping m, 14H), 7.67
(dd, 2H), 7.99 (m, 8H), ∼10% protic solvent residual coupled to
195Pt(J Pt-H ) 157 Hz). 13C{1H} NMR (75 MHz): δ (vs. CD2Cl2) 73.27
1
3
(t, J P-C ) 3.56 Hz), 75.66 (AXX′, J P-C ) 63.69 Hz, J P-C ) 2.01 Hz [2
routes]), 76.10 (t, J P-C ) 5.23 Hz), 92.94 (s), 96.03 (nonet, bound CH2-
3
3
Cl2), 108.40 (AXX′, J trans-P-C ) 34.73 Hz, J cis-P-C ) 0.00 Hz, J P-P′
)
15 Hz), 111.10 (AXX′, 2J trans-P-C ) 152.77 Hz, 2J cis-P-C ) 22.08 Hz, J P-P
) 15 Hz), 125.55 (s), 127.19 (s), 127.35 (s), 128.28 (t, J P-C ) 5.43 Hz),
128.66 (s), 129.99 (J Pt-C ) 26.02 Hz), 130.98 (J P-C ) 1.14 Hz), 131.23
2
4
(J Pt-C ) 9.66 Hz), 133.69 (AXX′, J P-C ) 59.09 Hz, J P-C ) -1.49 Hz,
J P-P ) 15 Hz), 135.25 (t, J P-C ) 5.9 Hz); δ (vs CDCl3) 72.63 (t, J P-C
)
1
3
3.49 Hz), 75.61 (AXX′, J P-C ) 59.60 Hz, J P-C ) 1.40 Hz [2 routes]),
3
75.72 (t, J P-C ) 5.16 Hz), 93.00 (s), 108.89 (AXX′, J trans-P-C ) 36.54
3
2
Hz, J cis-P-C ) -1.98 Hz, J P-P′ ) 15 Hz), 108.96 (AXX′, J trans-P-C
)
2
152.87 Hz, J cis-P-C ) 21.99 Hz, J P-P′ ) 15 Hz), 124.90 (s), 126.54 (s),
127.44 (J Pt-C ) 9.06 Hz), 127.81 (t, J P-C ) 5.41 Hz), 129.94 (J Pt-C
)
3
25.29 Hz), 130.46 (br), 130.74, 130.96, 133.28 (AXX′, J P-C ) 59.31
4
Hz, J P-C ) -1.71 Hz, J P-P′ ) 15 Hz), 134.96 (t, J P-C ) 5.93 Hz).
31P{1H} NMR (121 MHz, CD2Cl2): δ (vs 85% H3PO4), 14.77 (J Pt-P
)
F igu r e 2. Thermal ellipsoid drawing of one of the two
conformers of [Et3P]2Pt(Tta) (4) drawn at the 50% prob-
ability level. H atoms are omitted for clarity. Selected
bond distances (Å) and angles (deg): Pt1-P1 ) 2.306(6),
2406.9 Hz).
(11) (a) Du, C-J . F.; Hart, H.; Ng, K.-K. D. J . Org. Chem. 1986,
51(16), 3162-3165. (b) 2,6-Dibromoiodobenzene (5): 1H NMR (300
MHz) δ (vs CDCl3) 7.54 (d, 2H), 7.05 (t, 1H). (c) 2,6-Dibromoethynyl-
benzene (6): 1H NMR (300 MHz) δ (vs CDCl3) 7.53 (d, 2H), 7.02 (t,
1H), 3.67 (s, 1H); 13C{H} NMR (75 MHz) δ (vs CDCl3) 81.07, 86.87,
126.27, 126.96, 130.44, 131.54. (d) 2,2′,6,6′-Tetrabromotolan (7): 1H
NMR (300 MHz) δ (vs CDCl3) 7.58 (d, 2H), 7.04 (t, 1H); 13C{H} NMR
(75 MHz) δ (vs CDCl3) 95.49, 126.90, 127.12, 130.50, 131.75. Anal.
Calcd: C, 34.05; H, 1.22; Br, 64.72. Found: C, 33.36; H, 1.19; Br, 63.79.
(d) 2,2′,6,6′-Tetrakis((trimethylsilyl)ethynyl)tolan (8): 1H NMR (300
MHz) δ (vs CDCl3) 7.40 (dd, A of ABB′, 2H), 7.16 (BB′ of ABB′, 1H),
0.13 (s, 18H); 13C{H} NMR (75 MHz) δ (vs CDCl3) 0.05, 94.94, 99.55,
103.44, 126.26, 127.46, 129.69, 131.69. Anal. Calcd: C, 72.53; H, 7.52.
Found: C, 72.38; H, 7.61. (d) 2,2′,6,6′-Tetraethynyltolan (4): 1H NMR
(300 MHz) δ (vs CDCl3) 7.49 (d, 2H), 7.22 (t, 1H), 3.29 (s, 1H).
(12) Conditions iv and v give 83% and 90% yields per bond formed,
respectively.
Pt1-P2 ) 2.308(6), Pt2-P3 ) 2.312(7), Pt2-P4
)
2.292(7), Pt1-C1 ) 1.93(2), Pt1-C14 ) 1.99(2), Pt2-C7
) 1.97(2), Pt2-C8 ) 2.00(2), C1-C2 ) 1.23(3), C13-C14
) 1.20(3), C6-C7 ) 1.24(3), C8-C9 ) 1.21(3), C15-C16
) 1.18(2); P1-Pt1-P2 ) 98.8(2), P3-Pt2-P4 ) 98.0(3),
C1-Pt1-C14 ) 81.1(9), C7-Pt2-C8 ) 83.1(9), Pt1-C1-
C2 ) 175(2), Pt1-C14-C13 ) 177(2), C1-C2-C3 )
171(2), C12-C13-C14 ) 173(2), Pt2-C7-C6 ) 175(2),
Pt2-C8-C9 ) 173(2), C5-C6-C7 ) 173(2), C8-C9-C10
) 175(2), C4-C15-C16 ) 177(2), C11-C16-C15 )
179(2).
(13) Anal. Calcd for C46H66P4Pt2: C, 48.76; H, 5.87; P, 10.93.
Found: C, 48.92; H, 5.76; P, 10.67. FDMS: M+ 1132 (195Pt2). 1H NMR
(300 MHz): δ (vs CDCl3) 1.16 (m, 36H), 2.12 (m, 24H), 7.07 (t, 2H),
7.26 (d, overlaps solvent); δ (vs CD2Cl2) 1.19 (m, 36H), 2.15 (m, 24H),
7.17 (dd, 2H), 7.29, 7.32, and 7.35 (B′ portion of ABB′, 4H). 13C{1H}
NMR (75 MHz): δ (vs CD2Cl2) 8.64 (3J Pt-C ) 21.18 Hz), 17.82 (m),
tively.14-17 Acetylene and acetylide C-C distances in
3 and 4 are all within 1.18-1.24 Å, and acetylene
(14) X-ray data for 3: monoclinic, C2/c (No. 15), a ) 15.919(3) Å, b
) 19.063(4) Å, c ) 16.800(3) Å, â ) 116.88(3)°, Z ) 4. Data were
collected at 130 K in the range 1.81-27.50° in θ and were corrected
for absorption using ψ-scan data. Atomic positions were determined
principally by direct methods.14 Refinement15 for data with I > 2σ(I)
(4701 reflections) gave R1 ) 0.0248 and wR2 ) 0.0525; for all data
(5211 reflections) R1 ) 0.0318 and wR2 ) 0.0548.
1
2
3
96.55 (s), 106.50 (AXX′ +
/ AMXX′, J Pt-C ) 294.87 Hz, J trans-P-C )
3
1
3
34.08 Hz, J cis-P-C ) -1.59 Hz, J P-P′ ) 18 Hz), 111.97 (AXX′ +
/
3
2
2
AMXX′, J Pt-C ) 530.96 Hz, J trans-P-C ) 141.07 Hz, J cis-P-C ) 23.71
Hz, calcd J P-P′ ) 18 Hz), 126.28 (s), 128.00 (4J Pt-C ) 9.22 Hz), 130.17
(3J Pt-C ) 24.29 Hz), 131.12 (1:8:18:8:1), J Pt-C ) 9.42 Hz). 31P{1H}
4
NMR (121 MHz, CD2Cl2): δ (vs 85% H3PO4) 4.424 (J Pt-P ) 2275.7 Hz).

2584 Organometallics, Vol. 15, No. 11, 1996
Communications
C-C-C angles are nearly linear. Greater deviation
from linearity is observed for the Pt-C-C angle than
for the C-C-C angle of the acetylide in 3, while in 4
the angles deviate from linearity within respective esd’s
of one another. The positive 31P NMR chemical shifts
and the magnitudes of the 195Pt-31P coupling constants
for 3 (J Pt-P ) 2406.9 Hz) and 4 (J Pt-P ) 2275.7 Hz) are
consistent with a cis configuration for the phosphines
and for the acetylides about platinum.2c,18 The 81.1-
83.1° C-Pt-C angles dictated in these compounds by
the ethynyl-substituted tolans are among the smallest
observed.19 Planarity of 4 provides for efficient electron
delocalization with the platinum and central carbon
framework deviating slightly from planarity.20 The
angle between the plane of Pt2, P3 and P4 and that of
Pt1, Pt2, and carbons C1-C22 in 4 is 18.77(0.39)°. The
latter plane deviates by only 3.32(0.37)° from that of Pt1,
P1, and P2. In contrast the torsion of the plane of Pt
and two P atoms from that of the Pt and cyclyne frame
in 3 is 17.97(0.06)°. 195Pt-13C spin coupling extends
through up to four bonds of the enyne frameworks of 3
and 4. And in 4, C4 and C11 exhibit the inner three
peaks of a 1:8:18:8:1 splitting pattern indicative of
coupling to both Pt atoms. It is also interesting that
multiple pathways exist in 3 for 31P-13C coupling of the
cyclopentadienyl carbons: through the carbon π system,
Fe center, or Pt center. Spin coupling transmitted
through the Fe center as well as through the carbon π
system is observed in free Fdpp.21
“Tweezer” transition-metal bis(σ-acetylides) have been
reported to complex transition metals having a variety
of oxidation states.6 3 and 4 have the necessary
proximity of the acetylides and an additional uncoor-
dinated alkyne for further metal complexation, as has
been demonstrated in analogous silicon hetero-
cyclynes.22 The additional avenue of metal complex-
ation of these compounds may further enhance the
physical properties of extended systems. The structures
of 3, 4, and [Et3P]2Pt(Tba)23 provide the foundation for
constructing extended two-dimensional systems of pla-
nar metallacycles bridged by planar multidentate phos-
phines such as tetrakis(diphenylphosphino)tetrathia-
fulvalene.24 Incorporation of chiral phosphines is under
investigation as a means of altering NLO properties of
these structures.
Ack n ow led gm en t. We wish to thank the National
Science Foundation (Grant No. CHE-9412387) for fi-
nancial support, Dr. Robert Lattimer of BFGoodrich for
providing FDMS data, and Prof. Peter L. Rinaldi for
insightful NMR discussions.
Su p p or tin g In for m a tion Ava ila ble: For 3 and 4, single-
crystal X-ray experimental tables of data collection and
structure solution details, bond distances and angles, atomic
coordinates, thermal parameters, and least-squares-plane
deviations (17 pages). This material is contained in many
libraries on microfiche, immediately follows this article in the
microfilm version of the journal, and can be ordered from the
ACS; see any current masthead page for ordering information.
(15) SHELXTL PLUS version 4.03, Siemens Analytical Instruments,
Inc., Madison, WI, 1990.
(16) (a) Sheldrick, G. M. SHELXL-93; University of Go¨ttingen,
Go¨ttingen, Germany, 1993. (b) R1 is based on F, and R2 is based upon
F2.
(17) X-ray data for 4: tetragonal, I4h (No. 82), a ) 29.832(3) Å, c )
10.892(3) Å, Z ) 8. Data were collected at 138 K in the range
1.93-25.00° in θ and were corrected for absorption using ψ-scan data.
Positions of Pt atoms were determined by direct methods.14 The
remaining atomic positions were determined by successive difference
Fourier maps.15 The model used was that of a racemic twin, the two
hands differing in the direction of a 2-fold chiral axis passing through
OM9507437
(21) Fdpp 13C{H} NMR: (a) Pouchert, C. J .; Behnke, J . The Aldrich
Library of 13C and 1H FT NMR Spectra, 1st ed.; Aldrich Chemical:
Milwaukee, WI, 1993; Vol. 3, 772B. (b) (75 MHz) δ (vs CDCl3) 72.50
3
3
2
(dd, J P-C ) 3.68 Hz, J P-C ) 1.84 Hz), 73.77 (d, J P-C ) 14.72 Hz),
76.72 (d, overlaps solvent, 1J P-C ) ca. 7.36 Hz), 128.13, 128.22, 128.52,
133.34, 133.60, 138.94 (d, 1J P-C ) 10.12 Hz); δ (vs CD2Cl2) 72.72 (AXX′,
3J P-C 3.84 Hz, 3J P-C 1.59 Hz, J P-P′ ) 0.575 Hz), 74.11 (d, 1J P-C ) 14.91
Hz), 77.04 (d, 1J P-C ) 8.11 Hz), 128.44 (3J P-C ) 6.81 Hz), 128.79, 133.71
the two Pt atoms. Pt and
P atoms were treated as anisotropic
vibrators. For data with I > 2σ(I) (4217 reflections) R1 ) 0.0614 and
wR2 ) 0.1135; for all data (5391 reflections) R1 ) 0.0896 and wR2 )
0.1259. A solution in the centrosymmetric space group I41/a is not
reported due to a large number of systematic absence violations (84
primarily weak reflections of the type (hk0) h,k ) odd, and (00l) l )
2n but l * 4n) and an unsatisfactory refinement. A second data set
on another crystal yielded similar results.
2
1
(d, J P-C ) 19.46 Hz), 139.45 (d, J P-C ) 10.37 Hz).
(22) Guo, L.; Bradshaw, J . D.; Tessier, C. A.; Youngs, W. J .
Organometallics 1995, 14, 586-588.
(23) (a) Bradshaw, J . D.; Guo, L.; Tessier, C. A.; Youngs, W. J .
Abstracts of Papers, 208th National Meeting of the American Chemical
Society, Washington, DC; American Chemical Society: Washington,
DC, 1994; INOR 90. (b) Bradshaw, J . D. Ph.D. Dissertation, The
University of Akron, May 1996.
(18) Pregosin, P. S.; Kunz, R. W. In NMR Basic Principles and
Progress; Diehl, P., Fluck, E., Kosfeld, R., Eds.; Springer-Verlag: New
York, 1979; Vol. 16, pp 43-45.
(19) The smallest comparable angle in the literature5b is 84.5(6)°
a Pt(II) compound with two CtCC(OH)Me2 groups tethered
(24) (a) Fourmigue´, M.; J arshow, S.; Batail, P. Phosphorus, Sulfur,
Silicon Relat. Elem. 1993, 75, 175-178. (b) Fourmigue´, M.; Batail, P.
J . Chem. Soc., Chem. Commun. 1991, 1370-1372. (c) Fourmigue´, M.;
Batail, P. Bull. Soc. Chim. Fr. 1992, 129, 29-36. (d) Fox, M. A.;
Chandler, D. A. Adv. Mater. 1991, 3, 381-385.
for
together by a hydrogen-bonding water molecule.
(20) The largest deviation from the least-squares plane of Pt1, Pt2,
and carbons C1-C22 inclusive is 0.171 Å (0.021) for C8.