Richard J. Puddephatt

Coordination polymers: polymers, rings and oligomers containing gold(I) centres

Abstract A personal view is given of current research in the synthesis of macromolecules containing linear gold(I) centres. These range from conjugated, rigid-rod polymers to macrocyclic compounds, including novel catenanes and a doubly braided catenane formed in high yield by simple self assembly.

Pt-Re clusters and bimetallic catalysts

Abstract A review is given, from an organometallic perspective, of the current state of knowledge of the structure and activity of the bimetallic Pt-Re-Al 2 O 3 catalysts used in petroleum reforming and of the known heteronuclear Pt-Re cluster complexes. Some comparisons between proposed structures, bonding and reactivity in the Pt-Re clusters present in the heterogeneous catalytic materials and in the well-defined clusters are made.

Self-assembly of rings, catenanes, and a doubly braided catenane containing gold(I): the hinge-group effect in diacetylide ligands.

Reaction of the flexible dialkynyldigold(I) precursors X(4-C6H4OCH2C-CAu)2 with 1,4-bis(diphenylphosphino)butane gave complexes of formula [[[mu-X(4-C6H4OCH2CCAu)2[mu-(Ph2PCH2CH2CH2CH2PPh2)]]n]. The complexes exist as 25-membered ring compounds with n = 1 when X = O or S, as [2]catenanes with n = 2 when X = CH2 or CMe2, and as a unique doubly braided [2]catenane, containing interlocked 50-membered rings with n = 4 when X = cyclohexylidene. These compounds form easily and selectively by self-assembly; reasons for the selectivity are also discussed.

Controlled Self-Assembly of Cyclic Gold(I) Complexes: The First Family of Organometallic Catenanes

The value of n in Ph(2)P(CH(2))(n)PPh(2) controls whether a simple ring or a [2]catenane is formed in the reaction with a digold(I) diacetylide. Simple macrocyclic gold complexes are obtained for n=2 and the family of organometallic [2]catenanes for n=4 and 5 (see structure); a mixture of these products as well as a third isomer results when n=3.

Oxidative addition of aryl–halogen bonds to platinum(II) and the structure of a complex formed by aryl–fluoride oxidative addition

The complexes [PtMe2(Me2NCH2CH2NCHAr)] react by oxidative addition of the aryl–halogen bond when Ar = 2-BrC6H4, 2-CIC6H4, or C6F5 but by ortho-metallation when Ar = 2-FC6H4 or C6H5, and in the case where Ar = C6F5, the oxidative addition product adds acetone across the imine bond and the complex formed has been characterized crystallographically as a hydrogen-bonded dimer; the reactivity to oxidative addition can be correlated with the C–X bond energy.

Platinum(IV) hydride chemistry

Abstract A review is given for hydridoplatinum(IV) chemistry, especially in organometallic derivatives. It treats, both directly characterized complexes and those that are proposed as short-lived reaction intermediates. The complexes are of current interest as potential intermediates in CH activation reactions.

Macrocyclic gold(I) complexes and [2]catenanes containing carbonyl functionalized diacetylide ligands

Abstract The carbonyl derivatized bis(alkyne) OC(4-C 6 H 4 OCH 2 CCH) 2 was converted into the imine derivatives RNC(4-C 6 H 4 OCH 2 CCH) 2 [R=OH, NHC(O)NH 2 , NHC 6 H 3 -2,4-(NO 2 ) 2 ] and into the 4-bromomethyl-1,3-dioxolane derivative BrCH 2 C 2 H 3 O 2 C(4-C 6 H 4 OCH 2 CCH) 2 . The alkyne units in these compounds react with [AuCl(SMe 2 )] in the presence of base to form the corresponding digold(I) diacetylide complexes, that exist as insoluble oligomers or polymers. They reacted with the diphosphines Ph 2 PZPPh 2 [Z=CC, trans -HCCH and (CH 2 ) n , n =3–5] to give macrocyclic gold(I) complexes of the type [Au 2 (μ-LL)(μ-PP)], where LL is the diacetylide and PP the diphosphine ligand. The ability of these macrocyclic complexes to self-assemble to [2]catenanes has been studied. The ketone and imine derivatives do not form [2]catenanes because the orientation of the aryl groups is unfavorable, but the 1,3-dioxolane derivatives may catenate if the ring size is optimum.

New precursors for chemical vapour deposition of platinum and the hydrogen effect on CVD

Abstract Volatile organoplatinum(II) complexes have been studied as precursors for low temperature chemical vapour deposition (CVD) of platinum films. The temperature of CVD and the carbon contamination of the films can both be decreased by conducting the CVD process in the presence of hydrogen. Good adherence of the films to a silicon semiconductor is obtained.

Reactions and properties of some trimethyleneplatinum(IV) complexes : I. Thermal decomposition studies

Abstract The thermal decomposition of the complexes PtX2(C3H6), PtX2(C3H6)L2 and PtX2(C3H6)(LL) [where X = Cl, Br; L = pyridine, 4-methylpyridine; LL = 2,2′-bipyridyl, ethylenediamine] has been studied by differential scanning calorimetry and thermogravimetric analysis. The first estimated PtC bond strength for platinum—trimethylene complexes is reported.

Volatile organogold compounds [AuR(CNR1)]: their potential for chemical vapour deposition of gold

Abstract The preparation and characterization of a series of novel volatile organogold compounds of the type [AuR(CNR1)], where R = methyl, phenyl, vinyl, 1-propynyl and 3,3-dimethyl-butynyl, and R1 = methyl, ethyl, i-propyl, t-butyl, phenyl and cyclohexyl, are described. These compounds show sharply differing thermal stabilities. As a result of their volatility, the more stable members of the series have potential as chemical vapour deposition agents, selectively yielding essentially pure gold films under conditions of high vacuum and moderate temperature. This principle is demonstrated for these and other known volatile organogold compounds.