Pd(dppf)cl2: Structure, CAS Number, Properties and Uses

Pd(dppf)Cl2, CAS 72287-26-4, is a palladium(II) cross-coupling pre-catalyst that is 14.5% palladium by weight in its parent, desolvated form. Sigma-Aldrich classifies it as a wide-bite-angle Pd(II) pre-catalyst, most effective in Suzuki and Negishi couplings of alkyl partners and in Kumada couplings of secondary and primary alkyl Grignard reagents. Its square-planar structure, palladium content, preparation, catalytic cycle, decomposition point, commercial form and hazard classification follow below, section by section.

What Is Pd(dppf)Cl2?#

Pd(dppf)Cl2 is a palladium(II) coordination complex, [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II), that carries palladium, platinum group metal element 46, chelated by a wide-bite-angle bis-phosphine ligand and two chloride ions. Sigma-Aldrich lists the compound's CAS number as 72287-26-4 and describes its parent, desolvated form as a wide-bite-angle Pd(II) pre-catalyst. PubChem catalogs that desolvated complex, C34H28Cl2FeP2Pd, under CID 71310626, distinct from a second PubChem record, CID 54734621, that covers the dichloromethane solvate Pd(dppf)Cl2.CH2Cl2 (C35H30Cl4FeP2Pd, MW 816.6) suppliers actually ship, discussed further under Commercial Forms below; the two records share a name but carry different formulas and molecular weights, and the solvate carries no separate CAS of its own. Pd(dppf)Cl2 is one of the platinum group metal compounds and catalysts cataloged with a dedicated CAS registry entry on this site.

Pd(dppf)Cl2 Structure and Bonding#

Pd(dppf)Cl2 adopts a square-planar geometry around a four-coordinate, d8 palladium(II) center, the standard coordination geometry for a phosphine-ligated Pd(II) pre-catalyst. Two chloride ions occupy two of the four coordination sites, and the remaining two sites are filled by the two phosphorus atoms of a single 1,1'-bis(diphenylphosphino)ferrocene (dppf) ligand, which chelates the metal through both phosphines across the wide span of the ferrocene backbone, forming a 16-electron complex.

Sigma-Aldrich describes the resulting chelate as a wide-bite-angle ligand system, a geometry that opens more space around palladium than the narrower bite angle of simple bis(phosphine) pre-catalysts such as bis(triphenylphosphine)palladium chloride. A specific numeric bite angle for dppf could not be confirmed from an accessible primary source for this page, so none is stated here rather than estimated; what is established is the qualitative effect, which the compound's cross-coupling activity, covered under Uses below, draws on for hindered and alkyl coupling partners.

PGM Content of Pd(dppf)Cl2#

Palladium makes up 14.5% of Pd(dppf)Cl2 by mass in its parent, desolvated form, computed from palladium's atomic mass, 106.42 g/mol, divided by the complex's 731.7 g/mol molecular weight (106.42 / 731.7 = 0.1454), a figure computed from Sigma-Aldrich's published formula and molecular weight for PubChem CID 71310626. That basis matters commercially: the form suppliers actually sell, the dichloromethane solvate PdCl2(dppf).CH2Cl2 (CAS 95464-05-4), carries a lower 13.0 wt% Pd, per TCI America and Sigma-Aldrich product listings, because the added CH2Cl2 mass dilutes the same amount of palladium across a heavier molecule. Buyers pricing a batch against contained-palladium value should match the wt% figure to the CAS number printed on the certificate of analysis rather than defaulting to the parent-complex figure.

Physical and Chemical Properties#

Pd(dppf)Cl2 is an orange to purple solid, per Sigma-Aldrich, soluble in dichloromethane and DMF. ChemicalBook separately describes the compound's commercial-grade material as an orange-red powder that is slightly soluble in chloroform and methanol and insoluble in water, stored sealed in a dry place in an amber glass container and protected from light; the shade and solubility reported vary somewhat by source and by which solvate form is on hand. ChemicalBook also reports a melting point of 275 to 280°C with decomposition, meaning the solid breaks down rather than melting cleanly, along with a density near 1 g/cm3.

How Is Pd(dppf)Cl2 Made?#

Pd(dppf)Cl2 is made by treating the dppf ligand with an acetonitrile or benzonitrile adduct of palladium dichloride, a ligand-substitution reaction documented in Wikipedia's entry for 1,1'-bis(diphenylphosphino)ferrocene. The reaction proceeds in three stages:

1. Combine dppf with PdCl2(RCN)2, where R is methyl (acetonitrile adduct) or phenyl (benzonitrile adduct).
2. Displace both labile nitrile ligands as the two phosphorus atoms of dppf chelate the palladium center in their place.
3. Isolate Pd(dppf)Cl2, releasing two equivalents of the free nitrile RCN as byproduct.

The net reaction is dppf + PdCl2(RCN)2 to Pd(dppf)Cl2 + 2 RCN. TCI America and Sigma-Aldrich sell the compound as a finished pre-catalyst rather than publishing an in-house preparation or a reaction yield, and a chemist needing a lab-scale synthesis route should consult a primary synthetic-chemistry reference for exact conditions.

What Is Pd(dppf)Cl2 Used For?#

Pd(dppf)Cl2 is used for Suzuki and Negishi cross-coupling reactions, and Sigma-Aldrich singles it out as especially effective for alkyl coupling partners and for Kumada couplings of secondary and primary alkyl Grignard reagents, substrate classes that simpler palladium pre-catalysts handle poorly. A representative literature Suzuki-Miyaura coupling procedure, per TCI America, runs the compound at 10 mol% loading. Sigma-Aldrich also names a specific downstream application, Suzuki coupling in carbon-11 radiolabelling chemistry, where the wide-bite-angle dppf ligand's tolerance for hindered and functionalized partners suits the fast, small-scale couplings that radiochemistry demands. Palladium-catalyzed cross-coupling of this kind won Richard F. Heck, Ei-ichi Negishi and Akira Suzuki the 2010 Nobel Prize in Chemistry, per NobelPrize.org's press release, and Pd(dppf)Cl2 is one of the named pre-catalysts within the wider PGM catalysts in chemistry covered on this site.

Catalytic Cycle#

Cross-coupling reactions catalyzed by Pd(dppf)Cl2 run through the canonical three-step palladium cycle: oxidative addition, transmetalation and reductive elimination.

1. Add an organic halide (R-X) oxidatively across the palladium center, forming an R-Pd-X intermediate.
2. Transmetalate: an organoboron reagent with base delivers its organic group to palladium in a Suzuki coupling, or an organozinc reagent does the same in a Negishi coupling, displacing the halide.
3. Eliminate reductively: the two organic groups now bound to palladium combine to form the new carbon-carbon bond and release the catalytically active palladium species, ready to re-enter the cycle.

Pd(dppf)Cl2 enters this cycle as the pre-catalyst that supplies the palladium center; Sigma-Aldrich classifies it as a Pd(II) pre-catalyst, distinct from the Pd(0) cross-coupling catalysts, such as tetrakis(triphenylphosphine)palladium, that are already at the oxidation state the cycle runs through.

Commercial Forms, Purity and Price#

The standard commercial form of Pd(dppf)Cl2 is not the parent anhydrous complex but its dichloromethane adduct, PdCl2(dppf).CH2Cl2 (CAS 95464-05-4), which TCI America and Sigma-Aldrich both catalog as the routinely sold grade, assaying 13.0 wt% Pd against the parent complex's 14.5 wt% Pd. ChemicalBook lists the compound as an orange-red powder, sold sealed in a dry place in an amber glass container, protected from light. Suppliers price Pd(dppf)Cl2 as a catalysis-grade laboratory reagent rather than a bulk industrial commodity, in milligram-to-multi-gram research pack sizes, with larger contract-manufacture quantities available on request.

Safety and Hazard Classification#

Pd(dppf)Cl2 carries the GHS signal word Warning, per PubChem's aggregated classification for CID 71310626. GHS classification reported to PubChem: Self-heating Substances Category 2 (H252, "self-heating in large quantities; may catch fire"), Skin Irritation Category 2 (H315), Eye Irritation Category 2 (H319), Specific Target Organ Toxicity, Single Exposure, Category 3 (H335), and Aquatic Chronic Category 4 (H413), with pictograms GHS02 (flame) and GHS07 (exclamation mark). On the regulatory side, PubChem's ECHA-derived mirror lists the compound's REACH registration as "no longer valid," last updated in 2008, and separately assigns it German Water Hazard Class (WGK) 3, the most severe tier of that scale, plus Storage Class 11 for combustible solids. ChemicalBook's own handling guidance calls for storage in the dark, under an inert atmosphere, at room temperature, sealed in amber glass, consistent with the self-heating and irritant profile above; laboratories should handle the solid with gloves and fume-hood practice as that classification requires.

Where Pd(dppf)Cl2 Chemistry Stops: Medical and Pharmaceutical Platinum#

This page covers Pd(dppf)Cl2 as a laboratory and industrial cross-coupling reagent only, not as a platinum-based drug or medical treatment. Palladium's cross-coupling chemistry and platinum's medical chemistry are distinct subjects: platinum compounds such as cisplatin are pharmaceutical agents with their own dosing history, covered elsewhere on this site without clinical detail, while no pharmaceutical role for Pd(dppf)Cl2 appears in the facts gathered here.

Related PGM Compounds#

Pd(dppf)Cl2 shares its palladium(II) pre-catalyst chemistry with several other named palladium complexes in the same registry.

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