CHEMISTRY

Academician A. N. NESMEYANOV, O. V. NOGINA, and A. M. BERLIN

INTERACTION OF SODIUM CYCLOPENTADIENIDE WITH ALKOXYTITANIUM CHLORIDES

In studying the reactions of sodium cyclopentadienide with alkoxytitanium chlorides, mono-π-cyclopentadienyl derivatives of titanium—cyclopentadienyltitanium triethoxy- and tri-n-propoxytitanes—were isolated:

[
2\,\mathrm{Cl_2Ti(OC_2H_5)_2} + 3\,\mathrm{C_5H_5Na}
\longrightarrow
\mathrm{C_5H_5Ti(OC_2H_5)_3}
+
(\mathrm{C_5H_5})_2\mathrm{Ti}
\begin{matrix}
/\mathrm{OC_2H_5}\
\backslash\mathrm{Cl}
\end{matrix}
+
3\,\mathrm{NaCl},
]

[
\mathrm{ClTi(OC_3H_7)_3} + \mathrm{C_5H_5Na}
\longrightarrow
\mathrm{C_5H_5Ti(OC_3H_7)_3} + \mathrm{NaCl}.
]

These substances are colorless liquids, distilling in vacuum (b.p. (\mathrm{C_5H_5Ti(OC_2H_5)_3}) (106\text{–}107^\circ/3) mm, (n_D^{20}) 1.5500; b.p. (\mathrm{C_5H_5Ti(OC_3H_7\text{-}n)}) (106\text{–}107^\circ/0.5\text{–}1) mm, (n_D^{20}) 1.5272), and very sensitive to the action of atmospheric moisture.

[
\begin{aligned}
&\mathrm{C_5H_5Ti(OC_2H_5)_3}. \quad
\text{Found \%: } && \mathrm{C}\ 52.87;\ 52.90; \quad \mathrm{H}\ 8.23;\ 8.19; \quad \mathrm{Ti}\ 19.18;\ 19.00 \
&\text{Calculated \%: } && \mathrm{C}\ 53.23; \quad \mathrm{H}\ 8.12; \quad \mathrm{Ti}\ 19.30.
\end{aligned}
]

Molecular weight found (cryoscopic method in benzene) 236, 238; calculated 248.

[
\begin{aligned}
&\mathrm{C_5H_5Ti(OC_3H_7)_3}. \quad
\text{Found \%: } && \mathrm{C}\ 57.60;\ 57.69; \quad \mathrm{H}\ 9.17;\ 9.10; \quad \mathrm{Ti}\ 16.34;\ 16.03 \
&\text{Calculated \%: } && \mathrm{C}\ 57.92; \quad \mathrm{H}\ 9.02; \quad \mathrm{Ti}\ 16.50.
\end{aligned}
]

Molecular weight found 282, calculated 290.

It is interesting to note that, in contrast to the usual alkoxyl derivatives of titanium, one of whose characteristic properties is association in solution ((^{1-6})), π-cyclopentadienyltrialkoxytitanes are not associated in solutions, and even at a concentration of 1.7 mole %, the molecular weight of (\mathrm{C_5H_5Ti(OC_2H_5)_3}), determined cryoscopically in benzene, corresponds to that calculated for the monomeric compound. The structure of π-cyclopentadienyltriethoxy- and tri-n-propoxytitanes was proved by converting them into the trichlorocyclopentadienyltitanium described in the literature ((^{7,8})):

[
\mathrm{C_5H_5Ti(OR)_3} + 3\,\mathrm{CH_3COCl}
\longrightarrow
\mathrm{C_5H_5TiCl_3} + 3\,\mathrm{CH_3COOR},
]

where (R = \mathrm{C_2H_5};\ \mathrm{C_3H_7}\text{-}n).

In addition, the IR spectra of these compounds contain an intense band near (770\ \mathrm{cm^{-1}}), which also characterizes all three titanium derivatives with one π-cyclopentadienyl ring described in the literature ((^8)).

When trichloroethoxytitanium was used in the reaction with sodium cyclopentadienide, the interaction proceeded according to the equation:

[
\mathrm{Cl_3TiOC_2H_5} + 2\,\mathrm{C_5H_5Na}
\longrightarrow
(\mathrm{C_5H_5})_2\mathrm{Ti(OC_2H_5)Cl} + 2\,\mathrm{NaCl}.
]

[
\begin{aligned}
&\text{Found \%: } && \mathrm{C}\ 56.02;\ 55.74; \quad \mathrm{H}\ 5.77;\ 5.97; \quad \mathrm{Ti}\ 18.39;\ 18.69 \
&&& \mathrm{Cl}\ 13.47;\ 13.85 \
&(\mathrm{C_5H_5})_2\mathrm{TiCl(OC_2H_5)}. \quad
\text{Calculated \%: } && \mathrm{C}\ 55.72; \quad \mathrm{H}\ 5.84; \quad \mathrm{Ti}\ 18.52; \
&&& \mathrm{Cl}\ 13.70.
\end{aligned}
]

Molecular weight found (cryoscopically in benzene) 250; calculated 258. M.p. ((\mathrm{C}_5\mathrm{H}_5)_2\mathrm{Ti}(\mathrm{OC}_2\mathrm{H}_5)\mathrm{Cl}) 91–92°.

We have established that, under mild conditions (on heating for one hour at a bath temperature of 70–80°), alcohols decompose (\pi)-cyclopentadienyltitanium trialkoxides, forming the corresponding tetraalkoxytitanium and cyclopentadiene.

[
\mathrm{C}_5\mathrm{H}_5\mathrm{Ti}(\mathrm{OC}_2\mathrm{H}_5)_3 + \mathrm{ROH}
\rightarrow
(\mathrm{RO})_4\mathrm{Ti} + \mathrm{C}_5\mathrm{H}_6,
]

where (R=\mathrm{C}_2\mathrm{H}_5;\ \mathrm{C}_3\mathrm{H}_7\text{-}n).

The cyclopentadiene was isolated in the form of cyclopentadienylthallium.

[
\begin{aligned}
&\text{Found \%: } \mathrm{C}\ 22.29;\ 22.25;\quad \mathrm{H}\ 1.85;\ 1.84 \
&\mathrm{C}_5\mathrm{H}_5\mathrm{Tl}. \ \text{Calculated \%: } \mathrm{C}\ 22.29;\quad \mathrm{H}\ 1.87.
\end{aligned}
]

By the reactions of (\pi)-cyclopentadienyltri-(n)-propoxytitanium with acetyl chloride:

[
\mathrm{C}_5\mathrm{H}_5\mathrm{Ti}(\mathrm{OC}_3\mathrm{H}_7)_3 + \mathrm{CH}_3\mathrm{COCl}
\rightarrow
\mathrm{C}_5\mathrm{H}_5\mathrm{Ti}(\mathrm{OC}_3\mathrm{H}_7)_2\mathrm{Cl}
+ \mathrm{CH}_3\mathrm{COOC}_3\mathrm{H}_7,
]

[
\mathrm{C}_5\mathrm{H}_5\mathrm{Ti}(\mathrm{OC}_3\mathrm{H}_7)_3 + 2\mathrm{CH}_3\mathrm{COCl}
\rightarrow
\mathrm{C}_5\mathrm{H}_5\mathrm{Ti}(\mathrm{OC}_3\mathrm{H}_7)\mathrm{Cl}_2
+ 2\mathrm{CH}_3\mathrm{COOC}_3\mathrm{H}_7
]

mixed chlorides—alcoholates of (\pi)-cyclopentadienyltitanium—were obtained.

1) Chlorocyclopentadienyldi-(n)-propoxytitanium, which disproportionates on vacuum distillation (1 mm).

[
\begin{aligned}
&\text{Found \%: } \mathrm{C}\ 49.77;\ 49.61;\ \mathrm{H}\ 7.84;\ 7.65;\ \mathrm{Ti}\ 17.50;\ 17.64 \
&\mathrm{C}_5\mathrm{H}_5\mathrm{Ti}(\mathrm{OC}_3\mathrm{H}_7)_2\mathrm{Cl}. \ \text{Calculated \%: } \mathrm{C}\ 49.55;\quad \mathrm{H}\ 7.18;\quad \mathrm{Ti}\ 17.96.
\end{aligned}
]

Molecular weight found 270, calculated 267.

2) Dichlorocyclopentadienyl-(n)-propoxytitanium, b.p. 159–161°/2 mm.

[
\begin{aligned}
&\text{Found \%: } \mathrm{C}\ 39.23;\ 39.36;\ \mathrm{H}\ 4.99;\ 5.12;\ \mathrm{Ti}\ 28.85;\ 29.57;\ 28.98;\
&\qquad\qquad \mathrm{Cl}\ 19.52;\ 19.14 \
&\mathrm{C}_5\mathrm{H}_5\mathrm{Ti}(\mathrm{OC}_3\mathrm{H}_7)\mathrm{Cl}_2. \ \text{Calculated \%: } \mathrm{C}\ 39.54;\quad \mathrm{H}\ 4.97;\quad \mathrm{Ti}\ 29.18;\
&\qquad\qquad \mathrm{Cl}\ 19.71.
\end{aligned}
]

Molecular weight found 238, calculated 243.

These substances are greenish-yellow viscous liquids, decomposing under the action of atmospheric moisture, stable on storage at reduced temperature. Their IR spectra also contain absorption bands near (770\ \mathrm{cm}^{-1}).

Institute of Organoelement Compounds
Academy of Sciences of the USSR

Received
9 VI 1960

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