Editing Titanium tetrachloride (section)

==Chemical reactions==
Titanium tetrachloride is a versatile reagent that forms diverse derivatives including those illustrated below.<ref name="organoti">{{cite book |last1=Reetz |first1=Manfred T. |title=Organotitanium reagents in organic synthesis |date=1986 |publisher=Springer-Verl |location=Berlin Heidelberg New York Tokyo |isbn=0-387-15784-0 |edition=Reactivity and Structure Concepts in Organic Chemistry, Vol 24}}</ref>

[[Image:TiCl4cmpds.png|center|500px]]

===Alcoholysis and related reactions===
A characteristic reaction of {{chem2|TiCl4}} is its easy [[hydrolysis]], signaled by the release of [[hydrochloric acid|HCl]] vapors and [[titanium oxide]]s and [[oxychloride]]s. Titanium tetrachloride has been used to create naval [[smoke-screen|smokescreens]], as the hydrochloric acid aerosol and titanium dioxide that is formed scatter light very efficiently. This smoke is corrosive, however.<ref name="ullmann" />

Alcohols react with {{chem2|TiCl4}} to give alkoxides with the formula {{chem2|[Ti(OR)4]_{''n''}|}} (R = [[alkyl]], ''n'' = 1, 2, 4). As indicated by their formula, these [[alkoxide]]s can adopt complex structures ranging from monomers to tetramers. Such compounds are useful in [[materials science]] as well as [[organic synthesis]]. A well known derivative is [[titanium isopropoxide]], which is a monomer. [[Titanium bis(acetylacetonate)dichloride]] results from treatment of titanium tetrachloride with excess [[acetylacetone]]:<ref name=IS>{{cite journal|first1=C. A. |last1=Wilkie |first2=G. |last2=Lin |first3=D. T. |last3=Haworth |title=''Cis''-[Dihalobis(2,4-Pentaedionato)Titanium(IV)] Complexes |journal=[[Inorganic Syntheses|Inorg. Synth.]]|year= 1979 |volume=19 |pages=145–148 |doi=10.1002/9780470132500.ch33|isbn=978-0-470-13250-0 }}</ref>
:{{chem2|TiCl4 + 2 [[Acetylacetone|Hacac]] → Ti([[Acetylacetone|acac]])2Cl2 + 2 HCl}}

Organic [[amine]]s react with {{chem2|TiCl4}} to give complexes containing amido ({{chem2|R2N−}}-containing) and imido ({{chem2|RN(2−)}}-containing) complexes. With ammonia, [[titanium nitride]] is formed. An illustrative reaction is the synthesis of [[tetrakis(dimethylamido)titanium]] {{chem2|Ti(N(CH3)2)4}}, a yellow, benzene-soluble liquid:<ref>{{cite journal|first1= D. C. |last1=Bradey |first2=M. |last2=Thomas|title= Some Dialkylamino-derivatives of Titanium and Zirconium|journal=[[J. Chem. Soc.]]| year=1960| pages=3857–3861| doi= 10.1039/JR9600003857}}</ref> This molecule is tetrahedral, with planar nitrogen centers.<ref>{{cite journal|author1=M. E. Davie |author2=T. Foerster |author3=S. Parsons |author4=C. Pulham |author5=D. W. H. Rankin |author6=B. A. Smart |title= The Crystal Structure of Tetrakis(dimethylamino)titanium(IV)|journal=[[Polyhedron (journal)|Polyhedron]]| year=2006| volume=25| pages=923–929|doi= 10.1016/j.poly.2005.10.019|issue= 4}}</ref>
:{{chem2|4 LiN(CH3)2 + TiCl4 → 4 LiCl + Ti(N(CH3)2)4}}

===Complexes with simple ligands===
{{chem2|TiCl4}} is a [[Lewis acid]] as implicated by its tendency to [[hydrolysis|hydrolyze]]. With the [[ether]] [[tetrahydrofuran|THF]], {{chem2|TiCl4}} reacts to give yellow crystals of {{chem2|TiCl4(THF)2}}. With chloride salts, {{chem2|TiCl4}} reacts to form sequentially {{chem2|[Ti2Cl9]−}}, {{chem2|[Ti2Cl10](2−)}} (see figure above), and {{chem2|[TiCl6](2−)}}.<ref>{{cite journal|first1= C. S.|last1= Creaser |first2=J. A. |last2=Creighton|title= Pentachloro- and Pentabromotitanate(IV) ions|journal= [[Dalton Transactions|Dalton Trans.]]| year=1975| pages= 1402–1405|doi= 10.1039/DT9750001402|issue= 14 }}</ref> The reaction of chloride ions with {{chem2|TiCl4}} depends on the counterion. {{chem2|[N(CH2CH2CH2CH3)4]Cl}} and {{chem2|TiCl4}} gives the pentacoordinate complex {{chem2|[N(CH2CH2CH2CH3)4][TiCl5]}}, whereas smaller {{chem2|[N(CH2CH3)4]+}} gives {{chem2|[N(CH2CH3)4]2[Ti2Cl10]}}. These reactions highlight the influence of electrostatics on the structures of compounds with highly ionic bonding.

===Redox===
Reduction of {{chem2|TiCl4}} with [[aluminium]] results in one-electron reduction. The trichloride ([[Titanium(III) chloride|{{chem2|TiCl3}}]]) and tetrachloride have contrasting properties: the trichloride is a colored solid, being a [[coordination polymer]], and is [[paramagnetic]]. When the reduction is conducted in [[Tetrahydrofuran|THF]] solution, the Ti(III) product converts to the light-blue adduct {{chem2|TiCl3(THF)3}}.

===Organometallic chemistry===
{{Main|Organotitanium compound}}
The [[organometallic chemistry]] of titanium typically starts from {{chem2|TiCl4}}. An important reaction involves sodium [[cyclopentadiene|cyclopentadienyl]] to give [[titanocene dichloride]], {{chem2|TiCl2(C5H5)2}}. This compound and many of its derivatives are precursors to [[Ziegler–Natta catalyst]]s. [[Tebbe's reagent]], useful in organic chemistry, is an aluminium-containing derivative of titanocene that arises from the reaction of titanocene dichloride with [[trimethylaluminium]]. It is used for the "olefination" reactions.<ref name="organoti" />

[[Arene]]s, such as {{chem2|C6(CH3)6}} react to give the [[sandwich complex|piano-stool complex]]es {{chem2|[Ti(C6R6)Cl3]+}} (R = H, {{chem2|CH3}}; see figure above). This reaction illustrates the high Lewis acidity of the {{chem2|TiCl3+}} entity, which is generated by abstraction of [[chloride]] from {{chem2|TiCl4}} by [[aluminium trichloride|{{chem2|AlCl3}}]].<ref name="TiCplx">{{cite journal|first1=F. |last1=Calderazzo |first2=I. |last2=Ferri |first3=G. |last3=Pampaloni |first4=S. |last4=Troyanov |title= ''η''<sup>6</sup>-Arene Derivatives of Titanium(IV), Zirconium(IV) and Hafnium(IV)|journal=J. Organomet. Chem.| year=1996| volume=518|issue=1–2 | pages=189–196|doi= 10.1016/0022-328X(96)06194-3}}</ref>

===Reagent in organic synthesis===
{{chem2|TiCl4}} finds occasional use in [[organic synthesis]], capitalizing on its [[Lewis acid]]ity, its [[oxophilic]]ity, and the electron-transfer properties of its reduced titanium halides. It is used in the [[Lewis acid catalysis|Lewis acid catalysed]] [[aldol addition]]<ref>Mariappan Periasamy (2002): "New synthetic methods using the TiCl4-NR3  reagent system", ''[[Arkivoc]]'', p. 151-166.</ref> Key to this application is the tendency of {{chem2|TiCl4}} to activate [[aldehyde]]s (RCHO) by formation of [[adduct]]s such as {{chem2|(RCHO)TiCl4OC(H)R}}.<ref>{{cite encyclopedia|first1= L.-L. |last1=Gundersen |first2=F. |last2=Rise |first3=K. |last3=Undheim |encyclopedia=Encyclopedia of Reagents for Organic Synthesis| publisher = J. Wiley & Sons|year=2004 |title=Titanium(IV) chloride |editor-first =L. |editor-last=Paquette |location=New York, NY |doi=10.1002/047084289X.rt119.pub2}}</ref>