Cyclopentadienyl allyl palladium is an
organopalladium compound Organopalladium chemistry is a branch of organometallic chemistry that deals with organic palladium compounds and their reactions. Palladium is often used as a catalyst in the reduction of alkenes and alkynes with hydrogen. This process involves the ...
with formula (C
5H
5)Pd(C
3H
5). This reddish solid is volatile with an unpleasant
odor
An odor (American English) or odour (English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is caused by one or more volatilized chemical compounds ...
. It is soluble in common organic solvents. The molecule consists of a Pd centre
sandwiched between a Cp and
allyl ligand
Transition-metal allyl complexes are coordination complexes with allyl and its derivatives as ligands. Allyl is the radical with the connectivity CH2CHCH2, although as a ligand it is usually viewed as an allyl anion CH2=CH−CH2−, which is usual ...
s.
[
]
Preparation
This complex is produced by the reaction of allylpalladium chloride dimer
Allylpalladium(II) chloride dimer (APC) is a chemical compound with the formula η3-C3H5)PdCl">hapticity.html" ;"title="hapticity">η3-C3H5)PdClsub>2. This yellow air-stable compound is an important catalyst used in organic synthesis.Tatsuno, Y. ...
with sodium cyclopentadienide
Sodium cyclopentadienide is an organosodium compound with the formula C5H5Na. The compound is often abbreviated as NaCp, where Cp− is the cyclopentadienide anion. Sodium cyclopentadienide is a colorless solid, although samples often are pi ...
:
:2 C5H5Na + (C3H5)2Pd2Cl2 → 2 (C5H4)Pd(C3H5) + 2 NaCl
Structure and reactions
The 18-electron complex adopts a half-sandwich structure with Cs symmetry, i.e., the molecule has a plane of symmetry. The complex can be decomposed readily by reductive elimination
Reductive elimination is an elementary step in organometallic chemistry in which the oxidation state of the metal center decreases while forming a new covalent bond between two ligands. It is the microscopic reverse of oxidative addition, and is ...
.
:C3H5PdC3H5 → Pd(0) + C5H5C3H5
The compound readily reacts with alkyl isocyanide
An isocyanide (also called isonitrile or carbylamine) is an organic compound with the functional group –. It is the isomer of the related nitrile (–C≡N), hence the prefix is ''isocyano''.IUPAC Goldboo''isocyanides''/ref> The organic fragme ...
s to produce clusters with the approximate formula 2">d(CNR)2sub>n. It reacts with bulky alkyl phosphine
Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting ...
s to produce two-coordinated palladium(0) complexes:
:CpPd(allyl) + 2 PR3 → Pd(PR3)2 + C5H5C3H5
The compound has been used to deposit thin film chemical vapor deposition
Chemical vapor deposition (CVD) is a vacuum deposition method used to produce high quality, and high-performance, solid materials. The process is often used in the semiconductor industry to produce thin films.
In typical CVD, the wafer (substra ...
of metallic palladium
Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself na ...
.
References
{{Palladium compounds
Cyclopentadienyl complexes
Organopalladium compounds
Allyl complexes