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Homoleptic Thiolato Complexes Di- and Trinuclear TiIV Complexes with Unexpected MetalЦSulfur Cores [NMe2H2][Ti2(SMe)9] and [Ti3(SMe)12].

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heads result from the synthesis of the heteroundecanamides 12
and 13.
In this intramolecular carbon chain elongation of the
monosaccharide, a cyclic derivative of a nonose is formed.["] We
are attempting to synthesize higher functionalized components
by varying the glycal and by using other imides.
E.xpc~rinwntrrlProcidire
(1 S.6S.7R. 8S.Y R ) - 6 - hqdroay -8.9- bis(triniethylsiloxy)- 7-(trimethylsiloxymethyl)I I-oxa-2-ar;i-tric)clo[5.3.1.(iz.6]undecane-3-one13: 250 mgtl(0.62 mmol) were disaolvcd i n degassed, anhydrous acetonitrile or ii-hexane and irradiated for 4 h at
18 C- nith U V light ( I . = 154 nm. 60 W low-pressure mercui-y lamp). The solvent
was renio~ed,and the ra\v product purified on silica gel. From a conversion of 7 6 % ,
157 inp (X306) remain.
Received: April 19. 1994 [Z6863 I€]
German version. A i i g w . Clien?. 1994, 106, 2041
[I] .I. Thiein. W K l a f k e , Top. C'urr. C / I E I 1990.
~ I . 154. 285 -332.
[ 2 ] J. Thiein. P Ossowski. LiL+qs ,4811.C/imt. 1983. 2215 -2226.
131 J. Thiem, S. Kiipper. J. Schwentner. Lirhigr Ann. Chrm. 1985. 2 1 3 5 ~2150.
[4] L. Laupichler. C. E. Sowa. J. Thiem. Bioorg. M r d . Cheni., in press.
[S] Y K;in;ioka. Y. Hatanaka. J. Org. C l i m . 1976, 41. 400-401.
[6] Y. Kanaoka. A ( < . .Clirrn. Res. 1978. 11. 407-413.
171 A . G Griesheck. H. Mauder. A i i g c i i . C h r m 1992. 1 0 4 . 97-99: Angriv. Chmi.
1111. Ed. Eii,q/. 1992. 3 1 . 73- 75.
181 An cscdleiit suiiiinary can be round in. B. Giese. Radicub in Orguiiu Sj.nihesi.c.
Foi-iiiu/ioii of Curhoir-Corhoii Bond\, 1st edition, Pergamon. Oxford. 1986: H. G.
Viehe. Z. Janousek in Srrhstirrroir E//ecf.c iii Rutliu~l Cheiuisrr? (Ed.: R.
Meren!i). Reidel, Dordrecht, 1986: J. M. Tedder, A n p i . . Cheiii. 1982. Y4. 433442. .-!~pcl~.
c/letil.
I ~ U E".
. ~ n g i 1982.
.
21, 401 -410.
(91 Synthcss o l o t h e r nonose derivatives. particularly neuraniinic acid derivatives:
a ) R . .liilina. 1. Miiller. A. Vasella. R . Wyler. Curhohrrh R i x 1987, 164, 415432: b) S J. Danishefsky, M. P. De Ninno, S. H. Chen. J. Aiw. C%cni.S o c . 1988.
I I O . i Y l 0 3940:c ) C. Augt. C. Gautheron. S. David. A. Malleron. B. Gavage.
B. Bouxoii. Tcrruhcilron 1990. 46. 201 -214; d) K. Okamoto. T, Goto. ;hid. 1990.
46. 5 S 3 5 : e ) M.P DeNiniio, Si.nr/w.\ic 1991, 583.
Homoleptic Thiolato Complexes:
Di- and Trinuclear Ti'" Complexes
with Unexpected Metal- Sulfur Cores,
[NMe, H, ](Ti,(SMe),] and [Ti,(SMe) ,] * *
Wolfram Stuer, Kristin K i r s c h b a u m , and Dean M.
Giolando*
Normally six-coordinate metal centers have approximate
octahedral symmetry
Notable exceptions are transitionmetal complexes of the type [M(1,2-S2C,R,),]- and [M(1,2S,C6H&-, the majority of which adopt approximate trigonalprismatic symmetry (D3,).[21 Only recently, [ZrMe,]'- was
reported to be the first homoleptic complex with unidentate
hgdnds which exhibits non-0, symmetry.[31In the course of our
interest in complexes with six-coordinate metal centersC41 we
have recently reported an unusual (?,-distortion from 0, geometry in [Ti(S2C,H,),]'- ; the coordination about Ti can be
described as rkeii,-trapezoidal bipyramidal or, alternatively, the
S , polyhedron can be considered pentagonal-bipyramidal. lacking an equatorial vertex.[51To gain insights into the factors
[*I
[**I
Dr. D M . Giolaiido. W. Stiier. Dr. K . Kirschbaum
Dcparlinenr of Chemistry. University of Toledo
Toledo. OH 43606 (USA)
Telefaa\. Int. code f(419) 537-4033
Thls uork was aupported by the petroleum Research Fund. administered by
thc Amcrican Chemistry Society
governing this coordination geometry we have prepared six-coordinate Ti'" complexes containing unidentate thiolato ligands.
X-ray structural analysis has revealed a trigonal distortion of
the octahedral coordination about the Ti center in
[Ti,(SMe),]-, and a novel trigonal-prismatic coordination
geometry about the central Ti atom with two face-sharing O,,symmetric TiS, cores in [Ti,(SMe),,]. In addition titanium
thiolato complexes are of current interest due to their suitability
as precursors for the formation of titanium sulfide thin fihns by
chemical vapor deposition techniques. Success in this area
of research has been demonstrated with [Ti(StBu),] and
[TiCI,(HSR),], where R = c.jrlo-pentyl and cjclo-hexyl.".
Titanium thiolato complexes have been studied to a
limited extent, and general routes to homoleptic complexes
have been particularly elusive.'*. 91 Early work employed the
reaction of [Ti(NR;),] (R' = Me or Et) and RSH (R = Me, Et,
or iPr) which afforded complexes of general formula
[Ti(SR),(HSR),(NHR;),],
where ( x x) varied from 0.8 to
1.33.['01 Attempts to prepare [TI(SR),] from the reaction of
TiCI, and RSH/NH, were not entirely successful because a
mixture of compounds [TiCI,_,(SR),], where s varies from 1 to
4, was obtained.["]
When we treated [Ti(NMe,),] with seven molar equivalents of
MeSH, a dark red microcrystalline product, [NMe2H,]-l, was
obtained in good yield." ' I Almost black single crystals crystal-
+
"Me2H,1[Ti2(SMe),l
"Me2H21-I
lize from CH,Cl,/hexane mixtures; Figure 1 shows the solidstate structure of the [Ti,(SMe)J
ion.r'21Bond lengths and
7
Fig. 1 . Strucrure of 1. Important distances [A] and angles [ 1: Ti-S (bridging)
2.511(1)-2.575(1) A.1-i-S (terminal)2.321l(9) -2.362(1) A. !,rm.c-S-Ti-S 148.04(3)
162.42(4),cis-S-Ti-S 73.11(3)- I 1 5.63(3)
angles about the Ti centers compare well to those found for
other Ti'" complexes with MeS ligands."31The anion I contains
two Ti atoms each coordinated by three terminal and three
bridging MeS ligands. To a first approximation. the Ti2S,
framework may be described as a face-sharing bioctahedron
which is unique for sulfur donor ligands; the closest structural
is [Ti,CI,]-. While the TiCI, cores in [Ti,CI,]- are
close to the 0, limit. the TiS, cores in [NMe,H2]-I are significantly distorted with no major structural differences between
the two TiS, cores. Both TiS, cores are trigonally distorted from
0, to the midpoint of the O,-to-D,, reaction coordinate: Til,
twist angle of 31.10(4)' with dihedral angles between adjacent S,
faces (6) at h , of 40.37(4)'- and h , of 92.50(3)'; Ti2. twist angle
of 33.30(5)' with 6 at h , of 42.83(5)' and hz of 92.13(3) .[I5]
Interestingly, these MS, cores are similar to those observed for
several [M(1,2-dithiolato),12- complexes. where M = Ti or
Zr.["]
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The reaction of four equivalents of MeSH with [Ti(NMe,),]
results in the isolation of red-brown single crystals of
Figure 2 shows the solid-state structure of
[Ti,(SMe),,] (2)
the compound.["] The bond lengths are similar to those observed in [NMe,H,]-l. Complex 2 lies on a crystallographic C ,
axis and has a linear chain of three Ti atoms. the two outer Ti
atoms are coordinated by three terminal and three bridging MeS
ligands, while the central Ti atom is coordinated by six bridging
MeS ligands. Overall, the geometry of the Ti$,, framework
may be described as a trigonal-prismatic center with a facesharing octahedron on both trigonal faces. This novel arrangement has as its closest structural analogue in the metal thiolatobridged "double cubane" complexes." The arrangement of
ligands in the two outer TiS, polyhedra is similar; both
polyhedra are trigonally distorted from 0,: Ti2, twist angle of
49.22(3)' with 6 at h, of 60.57(2)" and b, of 78.44(2)"; Ti3. twist
angle of 44.50(3)' with 6 at h , of 55.69(2)" and h2 of
81.77(2)".[151A distortion is evidenced by the two Ti atoms
being about 0.4 A from the center of the S, core. shifted towards
the external S, faces. For the central Ti atom the TiS, core is
unusually close to the D,,,
limit: Til. twist angle of 10.69(2)'
with 6 at h i of 14.44(7)' and h, of 109.60(2)'.
6 = 8.00, 3.59, and 3.13 are slightly broadened and shifted; a
new feature at 6 = 3.31 appears as a sharp singlet at -25 "C,
which is severely broadened at -85°C; the resonance at
6 = 2.42 produces two broad singlets at 6 = 2.77 and 2.70 at
-25 "C, which merge to a singlet at 6 = 2.75 at -60°C and
then reappear at - 85 "C; and, those at 6 = 2.05 and 1.26 sharpen to a well-resolved doublet and quartet, respectively. For saturated solutions of [NMe,H2]-l at 21 ' C a new, very broad
feature at 6 z 3.4, is observed, while the resonance at 6 = 3.13
broadens and the remaining resonances are unchanged. Tentatively, these results indicate that on dissolution [NMe,H2]-l
affords 2 and. possibly the mixed complex [Ti(SMe),(SHMe),(NHMe,),] identified in the earlier literature.["
Synthetic and structural studies on this class of compounds
should have an impact on determining new aspects of six-coordinate complexes as well as providing advances to the development of titanium sulfide cathodes for battery technology. We
are continuing our efforts to prepare homoleptic monotitanium
complexes containing unidentate RS ligands and to elucidate
the solution chemistry of this class of compounds.
Experinientul Procediire
All reagents were purchased and used without further purification except where
noted. All solvents were freshly distilled: hexanes and T H F from Na,'benrophenone: CH,CI, from P,O,. All experimental work was conducted under an inert
atmoapherc.
[NMe,H,]-I: A reaction ilask containing [Ti(NMe2),] (0.450 g, 2 mmol) in T H F
(30 crn-l) was immersed in liquid nitrogen. and MeSH (0.78 cm'. 14 mrnol) was
added in one portion. On warming the mixture to 21 .C the color changcd from pale
yellow to dark red-brown. Stirring was continued at 21 C for 20 h. The solvent was
evaporated under vacuum without warming and the resultant dark red microcrystallinc solid was dried in vacuo for 2 h. correct C.H,N analysis. Single crystals
suitable for X-ray crystallography were obtained after storage of a iaturated hexane:CH,CI, solution at - 10 C for 1 week.
Fig. 2. Structure of 2. Important distances [A] and angles [ 1: Ti2 and Ti3: Ti-S
(bridging) 2.5580(8)- 2.5732(9), Ti-S (terminal) 2.3134(7) -2.3177(7). rrcins-S-Ti-S
158.03(4) -159.62(4), cis-S-Ti-S 75.12(3)-101.88(4): T i l : Ti-S 2.4319(8)2.4355(8). trans-S-Ti-S 128.89(3)- 143.74(3). cO-S-Ti-S 79 .62(3)- 84.14(2).
All of the trigonally distorted TiS, coordination geometries
observed in [NMe,H,]-l and 2 are unexpected. Sterically, an 0,
coordination, with a displacement of the Ti center towards the
terminal MeS ligands. is anticipated. Computational studiesr"]
on do-ML, complexes suggest a tendency for a twofold distortion from 0, towards a bicapped tetrahedral (BCT) geometry,
as observed[51in [Ti(S,C,H,),]2- which is midway along the
0,-to-BCT reaction coordinate. It is not readily apparent why
the structural features of [NMe,H,]-l and 2 are observed. However, as discussed131for the D,,structure of [ZrMe,12-, a reduction of symmetry induced by a second-order Jahn-Teller effect
may stabilize the trigonally twisted 0, coordination polyhedra.
Noteworthy, non-0, coordination geometries are favored by
insignificant, or the absence of, M-L n-bonding.
The behavior of these compounds in solution is complicated
and warrants further investigation. Our preliminary studies by
N M R spectroscopy suggest that [NMe,H,]-l dissolves to afford
2 and at least one other compound. In dilute solutions (ca.
M, CD,CI,, 21 "C) the 'H N M R spectrum of [NMe,H,]-l
contains two resonances at 6 = 3.59 and 3.13 (1 : I ratio), assigned to 2. and single resonances assigned to coordinated
Me,NH (6 = 8.00 and 2.42) and MeSH (6 = 2.05 and 1.26). As
the temperature decreases ( - 25, - 60. and then to - 85 "C) the
N M R spectra undergo a series of changes: the resonances at
2 : A reaction flask containing [Ti(NMe,),] (0.450 g. 2 mmol) in T H F (30 em3)was
itnmersed in a dry-ice!acetone bath. MeSH (0.45 cm3. 8 mmol) was added in one
portion. On warming the mixture to 21 C the color changed from pale yello* to
dark red-brown. Stirring was continued at 21 'C for20 h. The solvent was evaporated under vacuum with the aid of a water bath. After removal of volatiles in ~ C U
the initiallq oily residue solidified. The dark red-brown solid was dissolved in a
mixture of hexane (5Ocm-l) and CH,CI, (100cm-l) and stored at -10°C. Dark
red-brown single crystals suitable for X-ray crystallography were obtained. correct
C,H.N analysis.
Received: March 22, 1994 [Z 6786 IE]
German version: Angrw. Chim 1994, 106. 2028
[I] J. E. Huheey, l i i ~ r , p r i i t .Chemrstr!~,3rd ed. Harper & Row. New York. 1983.
Chap. 10.
[2] J. L. Martin, J. Takats. Cun. J. Chem. 1989, 67, 1914- 1923, and references
therein D. L. Kepert, Prog. Inorg. Chem. 1977. 23. 1 -65.
[3] P. M . Morse, G . S. Girolami. J. Am. Chem. Soc. 1989, 111.4114-4116.
[4] 1 Wegener. K. Kirschbaum, D. M. Giolando. J Chem. Sor. Dultun Truns.
1994. 1213-1218.
[5] M. Konemann, W. Stuer. K. Kirschbaum. D. M. Giolando. Pu/dirdron 1994,
13. 1415-1425.
[6] M. Bochmann. 1. Hawkins. L. M. Wilson. J Chem. Sw. Chem. Conmim. 1988.
344- 345.
(71 C. H. Winter, T. S. Lewkebandara. J. W Proscia, A. L. Rheingold. Inurg.
Chpm. 1993. 32. 3807-3808.
[XI P. J. Blower. J. R. Dilworth, Coord. Chem. Rev. 1987. 76. 121 185; C A.
McAuliffe, D. S. Barratt in Comprc,hensire Coordination Chrmrsrry. Vol. I l l
(Eds.: G. Wilkinson. R. D. Gillard. J. A. McCleverty), Pergamon. Oxford.
1987. Chap. 31. pp. 323-361.
[9] a) C. P. Rao. J. R. Dorfman. R. H . Holm, Inorg. Chem. 1986. 25. 428-439;
b) G. A. Sigel. P. P Power. h i d . 1987. 26. 2819 -2822.
[lo] D. C. Bradley, P. A . Hammcrsley. J Chrm. S u i . A 1967. 1894-1896.
[ l l ] NMR data of [NMe,H,j 1: ' H N M R (400 MHz. CDCI,. 21 T):6 = 3.59 (s.
Ti-SMe). 3.13 (a, Ti-SMe). 2.42 (s. NMe). 2.04 (br d. SMe). 1.22 (br q, SH):
"CNMR (CDCI,. 21 C APT): h' = 29.6 (primary, Ti-SMe). 28.0 (primary.
Ti-SMe)
[12] Crystal structure of [NMe,H,]-I and 2 : [NMelH,]-I: C,,H,,Ti,NS,.
M = 565.78. inonoclinic. P2,;a: u =16.366(4), h = 8.789(1). c =19.187(2) A.
~
O
COMMUNICATIONS
/ i = l l l . 2 0 ( 1 ) ; V = 2573(1)8L3. 2 = 4 ; p,,,,,=1.46gcm~’; ;.(Ma,,)=
0.71073A: li=33.2cm-’; T = 2 5 3 ? 1 K ; R = 0 . 0 3 2 for 3173 unique ohserved retlections (Ff > 3.0u(F:)) of 5570 total data, 348 refined parameters.
2 : CI2H,,,Ti3S,>.
M =708.89; hexagonal, R 3 : a =13.059(3), I‘ = 29.470(4) A;
1. = 435213) A3: Z = 6; ptIICd
= 1.62 pctn-’. poh. =1.59 gcm-’; J,(MoK,)=
0.71073A: 11 = 1 6 . 3 c m - ’ ; T = 1 7 3 * 1 K ; R=0.031 for 1580 unique ohscrked reflections (Ff > 3.0o(I-f)) of 2160 total data. Structure solution for
[NMe,H,]-I ( 2 ) . Measurement on an Enraf-Nonius CAD4 diffractometer.
graphitc monochromator, 1:) - 2fJ <can technique, 2(Jmdx
= 52.0 ; correction of
the anisotropic decay on I from 0.983 to 1.043 (from 0.943 to 1.010). empirical
.ihwrptioii corrcction o n I from 0.844 to 0.998 (from 0.973 t o 0.999). solution
bq dii-ect methods of MULTAN (SIR), refinement by full-matrix least-squares.
f’uiiction minimized was Znf\Ful
- \I-,\)’, weight I I is defined as 4F:,’u2(F,Z).
hydi-ogen atoms located and refined isotropically (hydrogen atoms calculated
o n idealized positions and included in the refinement with B,,, = 5.0 A’ as
.
peak in final
ridin$ iitwns). S = 1 . 0 6 (1.76). largest shift ~ 0 . 0 1 ~high
diflerrnce imp 0.3417) e k ’ (0 4319) e k ’ ) ) , low peak -0.12(7) e k ’
(
0.27(9) e k ’ ) . Further details of the crystal structure determination are
availiihle o n request fi-om the Director of the Cambridge Crystallographic
Data Centre, I ? Union Road. GB-Cambridge CB2 1EZ (UK). on quoting the
full 1otirniil citation.
[l3] T. A . Wark. D W. Stephan. Orgmiunie/u/lirs 1989. 8, 2836-2843.
[14] T I Kisteimucher. G . D. Stucky, I n o , ~ Chrm.
.
1971, /O. 122-132.
[IS] E. L. Muctterties. L. J. Guggenberger, J. A m . (‘hem. Soc. 1974. Y6, 1748-1756.
[I61 [Ti(S2C’2H4),]2-.see i-ef. [Ya]: anion 1 of [Ti(S,C,H,),]’-: J. H. Welch, R. D.
Bcreninn. P. Singh, Inorg. U i e n i . 1990,79.68- 73; [Zr(S2C,H,),12- ’ M. Cowie.
M . .I Bcnnett, ihiil. 1976. 15. 1595-1603.
[I71 NMR spcctroscopic data of 2 : ‘ H N M R (CD,CI,, 21 C). 6 = 3.56 (s. TiSMe). 3.12 (c. Ti-SMe); “C-NMR (CD,CI,. 21 ’C, APT): d = 29.55 (primary,
Ti-SMe). 28.35 (primary. Ti-SMe).
[18] S. C’iurli. M . Carrik. R. H Holm. Inorg. C/wni. 1990. 29, 3 4 9 3 ~3501. and
refercncer therein.
1191 A . Demolliens. Y. Jean. 0. Eisenstein, Orgunomc/ul/ic.r 1986.5. 1457-1464; K.
Tatsuini. I . Matsubara. Y Inoue. A. Nakamura. K. Miki. N. Kasdi. J A m .
C/wm Soc 1989. 111. 7766 7777.
~
tion of complexes [ T ~ T c C ~ , O ] [and
~ ~ [TpReO,] (Tp =
HB(pz),).[’] The uncoordinated pyrazolyl groups in the pzTp(B(pz),) and Tp ligands retain their donor ability and can be
protonated, as in [ ( p ~ T p ) ~ M ] or
[ ~ l [Tp*Rh(CO),] (Tp* =
HB(3,5-Me2pz)).I6]When two pyrazolyl groups are available,
bis chelates can be formed as in [(q3-CH,CRCH,)Pd(pz),B(pz),Pd(q3-CH2CRCH2)]+.I7]
A complex involving a
homoscorpionate free acid with all pyrazolyl groups participating in coordination has, however, never been obtained.
We have now synthesized and studied a new homoscorpionate
hgand, hydrotris(3-cyclohexylpyrazol-1-yl)borate ( = Tpcs).[xl
prepared from 3-cyclohexylpyrazole (1) and KBH,. This ligand
was expected to provide a larger hydrophobic pocket around the
metal than the related 3-isopropyl analogue TpiPrL9I
and its variantS T p i P r . 4Br,[91 Tp i P r . M c , [ l O ] and T P i P r Z .,[ I 1 ] . it is
’
of special interest because ligands of this type are used to construct model
compounds mimicking a variety of enzymes (Scheme
ap
HB-(N-N)-TI
\
[*] Prof. Dr. A. L. Rheingold. B. S. Haggerty
Department of Chemistry, University of Delaware
Newark. DE 19716 (USA)
Di-. S. Trofimenko
Du Pont Company. Experimental Station 302!216
Wilmington. D E 19880-0302 (USA)
Telefiix’ Int. code +(302) 695-3817
4
1
(N- N)- denotes the third, hidden 3-cyclohexylpyrarol-1-yl
group
As part of our investigations into complexes of type TpC?MX,
we tried to prepare [TpcyCuCl] ( 6 ) by adding a solution of
a4
Arnold L. Rheingold,* Brian S. Haggerty, a n d
Swiatoslaw Trofimenko”
In this communication we report the first example of an isolated and structurally characterized metal complex involving the
free acid of a new tris(pyrazoly1)borate as ligand. The scorpionato (polypyrazolylborato) ligands,”’ which have been known
for almost 30 years,[’] have been used in the form of their alkali
metal or thallium salts to synthesize a plethora of metal complexes. By contrast, their free acids [R,B(pz*),_,]H (pz* =
1-pyrazolyl or 1-pyrazolyl derivative; pz = pyrazolyl), obtained
on acidification of the anions [R,B(pz*),-,]-,
received scant
attention, although they have been known as long as the ligands
themselves.[3]Such protonated species are often the intermediate stage for ligdnd hydrolysis to boric acid and the corresponding pyrazole. It was noted quite early that the scorpionate free
acids can. in some cases, be used to obtain the same metal
complexes as those derived from the anions.l31 The use of free
acids was at times even necessary if the metal coreactant was
stable predominantly at low pH, as for instance in the prepara-
ap
r-N.
TINO,
H’ N- N
Scheme 1 .
The First Structurally Characterized Metal
Complex Involving the Free Acid of a New
Tris(pyrazoly1)borate as Ligand
KBH4
,N-
N1
HE- (N-N)-CU-CI
.?’CI
I
1
H2O/NaHCO3
6
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corel, tiiv, ti2, homoleptic, metalцsulfur, thiolate, unexpected, trinuclear, sme, complexes, nme2h2, ti3
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