ARBI AGHAZARIAN 971334160
Alkyl and Cyclopentadienyl Compounds of Titanium (IV)
INTRODUCTION
Titanium is the ninth most abundant element in the earth’s crust (0.57% by mass).
It occurs in rutile, TiO2, in the black beach sands of eastern Australia, and in the mineral
ilmenite, FeTiO3, in the United States, Canada, Malaysia, and elsewhere. It is a difficult
and expensive metal to produce. However, the cost of titanium is justified from its
unique properties. Worldwide production of titanium now exceeds 100,000 tons per
year.
Titanium is a transition metal with the electron configuration of [Ar] 4s2 3d2 and
forms many organometallic compounds. In this report, the Ti(IV) organic compounds
will be studied, in particular, the alkyl, aryl, and cyclopentadienyl (abbreviated as Cp)
complexes shown in table 1. The tetravalent Group IV organometallic compounds are
generally not very stable, mainly due to the observation that they do not attain the inert
gas configuration. For example, as successive methyl groups replace the halogen atoms
in TiCl4, the compounds become less thermally stable until TiMe4 is reached which
decomposes above –78C. The cyclopentadienyl compounds are significantly more
stable, and have been studied in much more detail.
HISTORY
Organotitanium chemistry began in the middle of the ninteenth century. Interests in this
field of study became evidently larger after World War II when increased attention was
paid to the study of metal organic compounds in general. These compounds were found
to have many industrial applications and as of then, organic titanium compounds are now
manufactured on an increasing scale.
A scheme is shown below of
bis(cyclopentadienyl)titanium dichloride and its versatility as a starting reagent.
1
Cp2TiClR
+
Cp2TiR2
CpTiOH +
Z n / HCl
Cp2Ti+
CpTiCl3
H2 O
T i Cl 4
NO
Cp2TiCl2
L i NR2
Cp2TiCl2TiCp2
Zn
CH3 Mg Cl
Zn ,
CO/ T HF
R
R'
Cp2TiMe2
Cp2Ti(NR2)
Cp2Ti(CO)2
2
RC CR'
Cp 2Ti
R'
(-CH4) H
2
C10H10Ti
R
N2
2
C10H10TiN
2
Raoul Feld and Peter L. Cowe. The Organic Chemistry of Titanium. London:
Butterworths & Co., 1965.
2
Table 1. Organotitanium compounds of study in this report.
Compound
MeTiCl3
Color
Violet
m.p. (ºC)
28.5
b.p. (ºC)
-
25
-
Me2TiCl2
Violet crystals
Red liquid
Black
-
145
CpTiMe3
Yellow
-
-
Most
halogenated
solvents, benzene
CpTiCl3
Orange-yellow
solid
Deep red
crystal
Orange
140-142
Decomp at 185
289
-
-
Decomp at 90
Toluen,
benzene
Sol. Toluene,
benzene
ether
EtTiCl3
Cp2TiCl2
Cp2Ti(CO) 2
Solubility
Carbon
tetrachloride
Carbon
tetrachloride
Carbon
tetrachloride
NOTE: The empty spaces are unknown data or data that was not found in the research.
ALKYL TITANIUM COMPOUNDS
The preparation of the titanium – carbon bond has interested chemists long time
ago, but nevertheless, had proved unsuccessful for many years. Chemists such as
Cahours in 1861 and Schumann in 1888 attempted to react diethyl zinc with titanium
tetrachloride, hoping to generate a carbon-titanium bond but found that this was not
observed. Levy, Razuvaev and Bogdanov tried similar attempts by reacting mercury
alkyls and alkyl magnesium halides, failing to observe an alkyl titanium compound. The
Fittig type reactions involving titanium tetrachloride with sodium and chlorobenzene,
were also reported to be failures in synthesizing aryl titanium compounds. These
conclusions reported by the authors along with several other reports were all in fact,
false: the authors were not aware that the isolated compounds were initially
organotitanium complexes that rapidly decomposed to give the observed inorganic
compounds. These early attempts were directed toward preparing tetraalkyl derivatives
analogous to the preparation of silanes SiR4 or zinc alkyls ZnR2 in which these were
distillable whereas the titanium analogs were thermally unstable. Thus, the tetravalent
organotitanium compounds formed immediately decomposed to give lower valent
titanium compounds and hydrocarbons:
2X3TiR  R2 + 2TiX3
X = alkoxy, Cl, Br
R = alkyl, aryl
The failures due to these early methods were due to lack of correct technique in isolating
the product. The actual first report of a successful reaction was by Hermann and Nelson
3
in 1952 where they reacted phenyl lithium with isopropyl titanate to yield phenyl lithium
tri-isopropoxide:
i
Ti(O Pr)
4
i
+ C6H5Br + Et2O + 2Li
i
C6H5Ti(O Pr) LiO PrLiBrEt2O
3
TiCl4
i
i
C6H5Ti(O Pr)
3
+ LiCl + LiBr + Ti(O Pr)
Et O
5 + 2
(53%)
The product was a white crystalline compound that only decomposed when the
temperature was raised above its melting point of 85-90C. It is quite an irritant.
The general synthesis of alkyltitanium (IV) dichloride compounds is the following:
R
R'Li
Cp2Ti
Cl
R
Cp2Ti
R'
where R, R' = alkyl, aryl
The carbon-13 NMR spectra of methyltitanium compounds has been determined. The
methyl signal of methyltitanium trichloride in the decoupled spectrum appears as a sharp
singlet at 113.0 (CD2Cl2).
Methyltitanium (IV) compounds
Alkyl titanium halides, in particular, the chlorides, were first isolated by a German
company which issued a patent for the preparation of alkyl titanium trichloride:
Me3Al + 2 TiCl4
MeTiCl3
Zn(CH3)2
Me2TiCl2
Hercules Powder Company has reported the following reaction:
TiCl4 + Et2TiMe2  Me2TiCl2 + Et2TiCl2
4
MeTiCl3
More recently, the German company has patented the preparation of methyl titanium
trichloride:
Me3Al + 2TiCl4 MeAlCl2 + 2MeTiCl3
The above preparation can be repeated for the synthesis of the tribromide in place of the
chloride by reacting titanium tetrabromide with dimethyl zinc in inert atmosphere. Even
today, the bromides have not been studied in great detail along with the other halides due
to problems with high reactivity and decomposition, resulting in unstable products as
well as high costs. Information on the costs was not manageable due to lack of reagent
prices in the Aldrich Catalogue.
One of the most commonly used reactions for the preparation of alkyl titanium
compounds is the reaction between organyl lithium and a titanium chloride compound:
R-Li + ClTiX3  R-TiX3
where X = Cl, Br, OR, NR2
Organyl titanium trichlorides act as strong Lewis acids. The Lewis acidity decreases as
the chlorine atom is replaced by alkoxides (-OR) or amides (-NR2):
RTiCl3 > RTiCl2(OR) > RTiCl(OR) 2 > RTi(OR) 3
As far as toxicity is concerned, the reactions involving alkyl titanium trichloride or
tribromide compounds do no lead to toxic materials. However, the titanium (IV) chloride
used in the preparation is highly toxic and can be hazardous.
Alkylation of tetrahalides:
TiCl4 + Me2AlCl
hexane, r.t.
MeTiCl3
or
TiCl4 + Me3Al
hexane, r.t.
MeTiCl3
Methyl titanium trichloride is a dark violet liquid. It forms dark violet solid Me2TiCl2 at
–80C. An IR study of MeTiCl3 has revealed that the carbon – titanium bond is a
relatively weak bond in comparison to the tin-carbon bond in MeSnCl3. The compound
is more stable as its dipyridyl complex, MeTiCl3. The UV spectrum of methyltitanium
trichloride is shown in Appendix A. It shows low intensity (at 75) at the first absorption
at 25 000 wavenumbers. This is considered to be a forbidden transition due to the three
carbon symmetry of the molecule shown below calculated by the CNDO-MO-SCF
procedure Manfred Reetz has reported:
5
Cl
H3C
Ti
CH3
CH3
Tetrahedral structure of Me3TiCl:
Manfred T. Reetz. Organotitanium Reagents in Organic Sythesis. Germany:
Springer-Verlag Berlin Heidelberg, 1986.
There is a second absorption band in the UV spectrum (43 000 wavenumbers) which
corresponds to a n* transition. Therefore, the second transition is due to the transition
of one of the lone electrons of the chlorine atom to a level which is antibonding between
the titanium and the carbon atom.
EtTiCl3
Bawn and Gladstone have reported the reaction between tetraethyl lead with excess TiCl4
at –80C:
Et4Pb + TiCl4
heptane, -80C
EtTiCl3 + Et3PbCl
Ethyltitanium trichloride is a red liquid and decomposes to ethane, butane, and TiCl3.
The cost of this reaction is not very high and can be reproduced on an industrial scale :
tetraethyl lead (5mL = $96.20CDN), heptane (500mL $40.70), titanium tetrachloride
(10g = $58). There is a large concern with this reaction in that the lead component and
the titanium tetrachloride are both highly toxic. New measures are being taken into
replacing the tetraethyl lead with other compounds. The structure is similar to that of the
methyltitanium trichloride.
CYCLOPENTADIENYL COMPLEXES (Cp)
INTRODUCTION
There have been many titanium (IV) compounds incorporating one or two h5-Cp groups
reported. Only a few will be discussed, mainly concerning the halides.
The Lewis acidities of alkyl titanium trichlorides were seen to decrease with alkoxide or
amide substitution. Cyclopentadiene ligands also have electron releasing effects such
that the Lewis acidity decrease dramatically when substituted with alkoxy groups.
However, M. Reetz reported that substituting with methyl groups instead, has the reverse
affect and the Lewis acidity of the compound increases. The rate observed was as
follows:
6
Cp2MeTiOR < CpMeTi(OR) 2 < MeTi(OR) 3 < Me2Ti(OR) 2 < Me3Ti(OR) < Me4Ti
In comparison to the alkyl or aryl titanium compounds, the cyclopentadienyl compounds
are much more stable and can be isolated easier in the laboratory. Here, the
cyclopentadiene rings have a stabilizing effect on the titanium alkyl bond. This is due to
the occupation of coordination sites that would otherwise be involved in the
decomposition process. Consequently, thermally stability is observed to increase
drastically in the series:
TiMe4 < CpTiMe3 < Cp2TiMe2 < Cp3TiMe
The Lewis acidities of this series is the reverse, where the alkyl compounds act as better
Lewis acids than the cyclopentadiene compounds.
There have been numerous titanium (IV) compounds reported, some for the purpose of
activity in catalytic and stoichiometric processes such as carbon monoxide insertion [1],
olefinmetathesis, reduction [2], hydrometallation [3] and carbometallation to name a few.
Cp2Ti(Ph)2
RBr
CO
Cp2 TiCl2/Na
Ph2PCH3
Cp2Ti
[1]
RH
[2]
RC CR' + Hal(CHMe2)2
i Cp2 TiCl2
R
ii I2
H
R'
[3]
I
Raoul Feld and Peter L. Cowe. The Organic Chemistry of Titanium. London:
Butterworths & Co., 1965.
One synthetic method of a cyclopentadienyl titanium complex is the reaction of
cyclopentadiene anions (lithium or sodium salts) with titanium tetrachloride to yield the
crystalline cyclopentadienyl titanium trichloride and bis(cyclopentadienyl)titanium
dichloride, depending upon the ratio of components used:
CpNa + TiCl3  Cp2TiCl2 + CpTiCl3 + NaCl
The pi bonded cyclopentadiene ligands are commonly observed because the Cp group has
a strong electron donating effect which results in greater stability. For example, CpTiCl3
is thermally much more stable than a sigma bonded compound such as MeTiCl3. In
addition, as mentioned previously, the cyclopentadiene ring makes the compound a
7
considerably weaker Lewis acid than the methyl group. 1H-NMR studies have revealed
little or no interaction with THF. The Lewis acidity of Cp2TiCl2 is even less pronounced.
CpTiCl3
The first cyclopentadienyl titanium trichloride (CpTiCl3) compound was reported in a
patent filed in 1953. It involved the halogenation of bis(cyclopentadienyl)titanium
dichloride with chlorine to give high yields of CpTiCl3:
Cp2TiCl2 + Cl2  CpTiCl3
This procedure requires extensive purification by sublimation but remains the most cost
effective procedure according to the Aldrich Catalogue.
Some general preparation methods used today are listed below.





Metal cyclopentadienide + TiCl4
Redistribution reaction of TiCl4 and Cp2TiCl2
Cleavage of Cp ligand in Cp2TiCl2 by a halogenating agent
Reaction between TiCl4 and a trimethylsilylCp or related derivative
Reaction between an acetyl halide and CpTi(OR) 3
Cyclopentadienyl titanium trichloride can be readily prepared by titanium tetrachloride
and bis(cyclopentadienyl)titanium dichloride which are reagents both commercially
available.
Higher yields result when prepared using Cp2TiCl2 + SO2Cl2 in SOCl2.
Photolysis of Cp2TiCl2 in chloroform or carbon tetrachloride also gives the mono
chloride compound by ring-metal bond scission followed by halogen abstraction from the
solvent. When benzene is used as solvent, the yields are lower.
hv
Cp2TiCl2
CpTiCl3 + Cl
.
Here, the chlorine radical combines with another
chlorine radial and forms chlorine gas. This procedure
is quite toxic due to the gas evolved.
The molecular structure of CpTiCl3 is given below. It was determined by Italian workers
using electron diffraction techniques. The structure has a ‘piano stool’ arrangement.
8
Structure of cyclopentadienyl titanium trichloride
O
Ti
Cl Cl Cl
Comprehensive Organometallic Compounds. Vol 3: Organotitanium Compounds. U.S.A., 1986
CpTiCl3 is readily soluble in many halogenated solvents and is reasonably soluble in
benzene.
The ring protons are magnetically equivalent and appear as single peak in the 1H-NMR
spectrum. Chemical shift data are (δ in ppm): THF (7.18), CDCl3 (7.06), CH2Cl2 (7.05),
CCl4 (7.21) and MeCN (7.25).
CpTiCl3 is a useful starting material for the preparation of bis(cyclopentadienyl)
derivatives containing different cyclopentadienyl ligands. An example is shown below:
Ph
i. LiAlH4
Me
ii. TiCl3Cp
Cp2TiCl2
Mono cyclopentadienyl titanium (IV) halides do not have much commercial importance.
The chloride form has an important role as a catalyst for the preparation of
bis(cyclopentadienyl) magnesium under mild conditions:
THF, 48h; r.t.
3C5H6 + Mg
CpTiCl3
.
Cp2Mg 2THF + C5H8
One of the most recent applications of CpTiCl3 is as very useful reagent for incorporation
of TiCp moiety into a variety of complex molecules. Cp-M complex research is really
flourishing due to the many new compounds that can be synthesized.
9
Cp2TiCl2
Bis(cyclopentadienyl)titanium dichloride is a red crystalline product which is
commercially available. It has a distorted tetrahedral structure (see structure below). It is
reported to behave as a homogeneous catalyst for alkene polymerization in the presence
of aluminum alkyls (Ziegler-Natta). It is a versatile reagent; it can be reacted to lose a
cyclopentadiene ring or a chlorine atom.
Earlier attempts in structure determination using X-ray techniques showed variance to
what is now considered to be the structure of Cp2TiCl2. An X-ray crystal structure
determination and electron diffraction data has revealed the following tetrahedral crystal
structure:
Structure of bis-(cyclopentadienyl)titanium dichloride
O
Ti
O
Cl
Cl
Comprehensive Organometallic Compounds. Vol 3: Organotitanium Compounds. U.S.A., 1986
The first Cp2TiCl2 was prepared by Summers and Uloth using titanium tetrachloride and
a cyclopentadiene salt:
TiCl4 + 2LiC5H5  Cp2TiCl2 + 2LiCl
Even today, this procedure is used along with xylene-petroleum ether as solvent which
results in yields of up to 70% as well as low costs according to the Aldrich Catalogue.
The lithium salt can be substituted with sodium which is just as effective or even better.
Bis(cyclopentadienyl)titanium dichlorie is soluble in acetone, benzene, chloroform,
dichloromethane-petroleum ether and slightly soluble in thionyl chloride.
The use of Grignard reagents can also be applied to organotitanium synthesis but reaction
conditions must be controlled for the Grignard reagent to remain active throughout the
process:
TiCl4 + 2CpMgBr  Cp2TiCl2 + 2ClMgBr
Another preparation method involves the decomposition of the unstable Cp2Ti(Ph)2
compound. However, this method is very inefficient but yet, cost effective.
Cp2Ti(Ph)2 + 2HCl  Cp2TiCl2
10
Or similarly
Cp2TiPh2 + HgCl2  Cp2TiCl2
Cp2Ti(Ph)2 + CCl4 + Hg  Cp2TiCl2 + PhHgCl + C6H5Cl
Cyclopentadiene in pyridine can also yield bis(cyclopentadienyl)titanium dichloride:
TiCl4 + 2C5H6 + 2py  Cp2TiCl2 + 2pyHCl
The problem associated with this reaction is that low yields of the titanium complex are
obtained (less than 3%). This low yield is due to the polymerization of the
cyclopentadiene and the formation of amino-titanium tetrachloride complexes.
In general, the cost incorporated into the synthesis of Cp2TiCl2 is not the general concern
but rather, the yield obtained.
In additon, vacuum sublimation techniques at
160C/0.1Torr and 190C/2Torr for pure recrystallization are required.
Preparation of the fluoride, bromide, and iodide complexes are illustrated below:
Cp2TiBr2 + HF  Cp2TiF2
TiBr4 + 2CpMgBr  Cp2TiBr2
Cp2TiBr2 + CH3COCH3 + KI  Cp2TiI2
Infrared spectroscopy of the compound reveals four strong bands in the characteristic
frequencies of 3100 (CH stretch), 1435 (CC stretch), 1020 (CH deformation in plane),
and 820 cm-1 (CH deformation out of plane). The H-NMR spectrum shows a sharp
singlet. The chemical shift values (δ in ppm) for various solvents are: benzene (5.92),
toluene (5.88), acetone (6.62), CH2Cl2 (6.55), and CDCl3 (6.59).
Cp2TiCl2 is a widely used starting reagent for the preparation of a large number of
organometallic compounds of titanium. It has found an application as a catalyst or
catalyst component for a variety of hydrometallation and carbometallation reactions as
well as transformations involving Grignard reagents.
Cp2Ti(CO) 2
The synthesis and reactivity of titanium carbonyls have developed relatively slowly. The
first carbonyl-titanium complex was reported by Murray of Monsanto Co. in 1959. The
compound was Cp2Ti(CO) 2 and the structure is illustrated below. Even today, other
carbonyl – cyclopentadienyl titanium complexes have not become very popular due to
their relative instability. Only Cp2Ti(CO) 2 is stable with titanium (IV) oxidation state.
11
All other compounds containing the CO ligand are poorly established due to the lack of
pi-bonding electron density on titanium.
Structure of bis-(cyclopentadienyl)titanium dicarbonyl
O
O
Ti
O
C
C
O
Kazu Nakamato. Infrared and Raman Spectra of Inorganic and Coordination Compounds, Part B:
Application with Coordination, Organometallic, and Bioinorganic Chemistry, 5 th Edition. U.S.A.: John
Wiley & Sons Inc., 1997.
It has been well established that the number of CO stretching bands observed in the
infrared spectrum depends on the local symmetry of the Ti(CO) 2 group. The infrared
spectrum of the compound has only 2 CO stretching bands. These are in accordance with
the local symmetry.
The simplest and most cost effective way of preparing bis-(cyclopentadienyl) titanium
dicarbonyl is through the reductive carbonylation of bis-(cyclopentadienyl)titanium
dichloride:
Cp2TiCl2
2CO, C5H5Na
Cp2Ti(CO)2
This method is the most widely used procedure due to the commercial availablility of
Cp2TiCl2 as well as the ease of the direct reaction route required. This process was first
reported by Calderazzo et al whereby Cp2TiCl2 was reduced by sodium naphthalene in
THF for 24hrs. The green product was then treated with carbon dioxide in toluene for
4hrs, resulting in 10% yield:
2CO, Toluene
Napthalene, THF
Cp2TiCl2
24hrs, 25C
Cp2Ti
4hrs, 20C
Cp2Ti(CO)2
(Titanocene)
Cp2Ti(CO) 2 is a red/brown solid
12
Other methods include the insertion of carbon monoxide using cyclopentadienyl titanium
alkyl or aryl compounds.
Cp2TiR2 + 2CO  Cp2Ti(CO) 2
R = alkyl, aryl
ALKYL – CYCLOPENTADIENYL COMPOUNDS
Cp2TiR2 – CpTiMe3
The discussion involving the alkyl-cyclopentadienyl titanium complexes will be kept
short and brief. It is a large field in research today and many different compounds are
synthesized with varying properties. Thus, the application of these compounds are quite
extensive. The structures are given below:
Structure of cyclopentadienyl titanium trichloride
O
H3C
Ti
CH3
CH3
This structure is slightly different
than CpTiCl3 where the methyl
groups are larger in size and cause
steric hindrance, resulting in smaller
angle between the Cp ring and each
methyl.
Structure of bis(cyclopentadienyl) titanium dichloride
O
O
Ti
CH3
CH3
Manfred T. Reetz. Organotitanium Reagents in Organic Sythesis. Germany:
Springer-Verlag Berlin Heidelberg, 1986.
13
One of the most convenient ways of preparing bis(cyclopentadienyl) titanium dialkyls is
by reacting proper chloro-titanium precursors with alkyl lithium reagents:
Cp2TiCl2 + 2RLi  Cp2TiR2
CpTiCl3 + 3MeLi  CpTiMe3
CpTiMe3 is a crystalline air stable compound with a melting point of 97C. It has an
orange yellow color and is reactive towards moisture. The ethyl and n-butyl analogs are
reported to be thermally less stable. By adding cyclopentadiene or trimethyl silyl
(Me3SiCH2--) groups to the end methyl groups or simply replacing the methyl groups
with cyclopentadiene rings, the thermally stability of the compound is greatly increased.
This is mainly due to the electronic and steric effects of the Cp ligand.
Cp2TiMe2 is an unstable yellow compound which decomposes at 100C. The most
effective procedure for synthesis is:
2MeI + Cp2TiCl2  Cp2TiMe2
Another form of synthesis involved use of Grignard reagent in tetrahydrofuran but the
yields are low (1%):
Cp2TiCl2 + 2MeMgI  Cp2TiMe2 + MgI2 + MgCl2
Due to the thermal instability of this compound, a clean absorption spectrum was not
found.
CONCLUSION
Alkyl and cyclopentadienyl complexes of titanium have been studied and
discussed in this report. Due to the limitation and to the huge branch of this field of study
and the many molecules that have been prepared, only a few compounds were focused
on. Alkyl titanium compounds have found a very large role as catalysts, especially in the
Ziegler-Natta catalyst systems. The cyclopentadienyl compounds of titanium have also
been quite useful in the reactions mentioned, but nevertheless, these compounds are
relatively recent and a large future holds for them, considering all the variations that can
take place by ligand substitution. Thus, organotitanium compounds are becoming quite
useful in industrial and commercial applications.
14
ARTICLE REVIEW
The sources used were not concentrated on the topic of interest. In particular, the
articles or journals were very plentiful. Full searches using the chemical index, Web of
Science, Dictionary of Inorganic Compounds, and many other referencing sources did not
give much relevance to journals on alkyl or cyclopentadienyl titanium compounds.
Nevertheless, a few articles were found and only really provided structural, infrared, and
nuclear magnetic resonance data. Since these organotitanium compounds are relatively
new and not much is known about them, Carbon-13 NMR data was not found for any of
the compounds along with some of the characteristic properties, listed as blank in table 1.
Also, the applications of the compounds were limited. In all, it was quite a difficult topic
due to the limitations encountered.
The majority of the information was based on books and volumes dating back to
1986. It seemed as though not much research was pulicated after 1985 on the
compounds. In addition, this field is so diverse that if some cyclopentadienyl compounds
of titanium were found, they were not much of use. For example, Cp complexes are
numerous since the other ligands can be varied with almost any functional group. Due to
the limitation of the report and scarcity of the information, the project was dealt with the
most common forms which the information on them was also little or not very recent
(1990-99). One of the other problems encountered was hazard data on the compounds.
No such analyses have been conducted, only general trends that alkyl titanium
compounds do not lead to toxic materials. Chemfinder was resorted to for information
but the only results obtained were that the compounds were not listed.
15
BIBLIOGRAPHY
Advances in Organometallic Chemistry, VOL 24. Photochemistry of Ti alkyl complexes.
1985.
Advances in Organometallic Chemistry, Vol 25. Titanium-Cp Complexes. 1986.
Comprehensive Organometallic Compounds. Vol 3:
U.S.A., 1986
Organotitanium Compounds.
Charles M. Lukehart. Fundamental Transition Metal Organometallic Chemistry. U.S.A.:
Brooks/Cole Publishing Company, 1985.
D. L. Kepert. The Early Transition Metals. New York, U.S.A.: Academic Press Inc.,
1972.
F. Albert Cotton. Advanced Inorganic Chemistry: A Comprehensive Text. U.S.A.: John
Wiley & Sons, Inc., 1972.
John J. Eisch and R. Bruce King. Organometallic Synthesis: Vol 1 Transition Metal
Compounds. New York: Academic Press Inc., 1965.
Kazu Nakamato.
Infrared and Raman Spectra of Inorganic and Coordination
Compounds, Part B: Application with Coordination, Organometallic, and Bioinorganic
Chemistry, 5th Edition. U.S.A.: John Wiley & Sons Inc., 1997.
Manfred T. Reetz. Organotitanium Reagents in Organic Sythesis. Germany: SpringerVerlag Berlin Heidelberg, 1986.
M.K. McQuillan and A.D. McQuillan. Titanium. New York: Butterworths Publications
Ltd., 1956.
Peter Briant and Jennifer Green. Journal of the American Chemical Society., 1989, 111,
3434-3436.
Raoul Feld and Peter L. Cowe.
Butterworths & Co., 1965.
The Organic Chemistry of Titanium.
London:
R.W. Harrigan, George S. Hammond, and Harry B. Gray. Photochemistry of
Titanocene(IV) Derivatives. Journal of Organometallic Chemistry, 81 (1974) 79-85.
Elsevier Sequoia S.A., Lausannne.
William L. Jolly. The Synthesis and Characterization of Inorganic Compounds.
Englewood Cliffs, U.S.A.: Prentice Hall Inc., 1970.
16
17