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Richard J Puddephatt

Publications and source records attributed to Richard J Puddephatt.

At least 19 recordsLinked to original sources
PubMed2006

Self-assembly of coordination polymers: evidence for dynamic exchange between oligomers in solution and the isolation of a homochiral decagold(I) oligomer.

Reactions of the precursor molecules [Au2(mu-BINAP)(O2CCF3)2], 1a, racemic BINAP, 1b, S-BINAP (BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl) with the easily exchanged linear bis(pyridine) ligand 1,2-trans-bis(4-pyridyl)ethylene (bipyen) gave the polymeric complex [{Au2(mu-R-BINAP)0.5(mu-S-BINAP)0.5(mu-bipyen)}n](CF3CO2)2n, 2a, but either the polymer [{Au2(mu-S-BINAP)(mu-bipyen)}n](CF3CO2)2n, 2b, or the remarkable oligomeric [Au10(mu-S-BINAP)5(mu-bipyen)4(kappa1-bipyen)2](CF3CO2)10, 3, respectively. The type of oligomer 3 is a missing link in the ring-opening polymerization of macrocyclic coordination compounds.

Journal Article↗
PubMed2006

Structure and dynamics of tetrakis(thiophosphinato)resorcinarene complexes of silver(I), gold(I), and palladium(II).

The coordination chemistry of the tetrakis(thiophosphinato)resorcinarene sulfur-donor ligands [(C6H2CH{CH2CH2Ph})4{OC(O)R}4{OP(=S)Ph2}4] (L), where R = OCH2Ph, 4-C6H4CH3, C6H11, C4H3S, or OCH2CCH, is reported. Both silver(I) and gold(I) form cationic complexes of the type [LM2]2+, in which the ligand acts as a bis(chelate) in forming complexes with linear S-M-S (M = Ag or Au) stereochemistry. Gold(I) also forms the unusual complex [L(AuCl)2][LAu2]2+, which forms a supramolecular polymer through intermolecular aurophilic attractions. Palladium(II) forms the complex [LPd2Cl2(mu-Cl)2], in which the dipalladium(II) unit extends the natural bowl structure of the resorcinarene. The solid-state and solution conformations of the complexes, as determined by X-ray structure determination and NMR spectroscopy, respectively, are similar, but several complexes were found to exhibit dynamic behavior in solution, involving either conformational mobility of the resorcinarene unit or intermolecular ligand exchange.

Crystallography, X-Ray↗
PubMed2006

Ring-opening polymerization of coordination complexes: silver(I) complexes with bis(amidopyridine) ligands derived from thiophene.

The thiophene-based bis(N-methylamido-pyridine) ligand SC4H2-2,5-{C(=O)N(Me)-4-C5H4N}2 reacts with silver(I) salts AgX to give 1 : 1 complexes, which are characterized in the solid state as the macrocyclic complexes [Ag(2){SC4H2-2,5-(CONMe-4-C5H4N)2}2][X]2, which have the cis conformation of the C(=O)N(Me) group, when X = CF3CO2, NO3, or CF3SO3 but as the polymeric complex [Ag(n){SC4H2-2,5-(CONMe-4-C5H4N)2}n][X]n, with the unusual trans conformation of the C(=O)N(Me) group, when X = PF6. The bis(amido-pyridine) ligand SC4H2-2,5-{C(=O)NHCH2-3-C5H4N}2 reacts with silver(I) trifluoroacetate to give the polymeric complex [Ag(n){SC4H2-2,5-(CONHCH2-3-C5H4N)2}n][X]n, X = CF3CO2. The macrocyclic complexes contain transannular argentophilic secondary bonds. The polymers self assemble into sheet structures through interchain C=O...Ag and S...Ag bonds in [Ag(n){SC4H2-2,5-(CONMe-4-C5H4N)2}n][PF6]n and through Ag...Ag, C=O...Ag and Ag...O(trifluoroacetate)...HN secondary bonds in [Ag(n){SC4H2-2,5-(CONHCH2-3-C5H4N)2}n][CF3CO2]n.

Journal Article↗
PubMed2006

Homochiral and heterochiral coordination polymers and networks of silver(I).

The self-assembly of racemic and enantiopure binaphthylbis(amidopyridyl) ligands 1,1'-C(20)H(12){NHC(O)-4-C(5)H(4)N}(2), 1, and 1,1'-C(20)H(12){NHC(O)-3-C(5)H(4)N}(2), 2, with silver(I) salts (AgX; X = CF(3)CO(2), CF(3)SO(3), NO(3)) to form extended metal-containing arrays is described. It is shown that the self-assembly with racemic ligands can lead to homochiral or heterochiral polymers, through self-recognition or self-discrimination of the ligand units. The primary polymeric materials adopt helical conformations (secondary structure), and they undergo further self-assembly to form sheets or networks (tertiary structure). These secondary and tertiary structures are controlled through secondary bonding interactions between pairs of silver(I) centers, between silver cations and counteranions, or through hydrogen bonding involving amide NH groups. The self-assembly of the enantiopure ligand R-1 with silver trifluoroacetate gave a remarkable three-dimensional chiral, knitted network composed of polymer chains in four different supramolecular isomeric forms.

Journal Article↗
PubMed2005

Tetraphosphinite resorcinarene complexes: silver(I) capsule complexes.

Resorcinarene tetraphosphinite ligands, P4, react with silver(I) trifluoroacetate or silver(I) triflate, AgX, to give the corresponding [Ag4X4(P4)] complexes. The resorcinarene skeleton in these complexes adopts a boat conformation with the silver(I) phosphinite units on the horizontal, rather than the upright, arene units of the resorcinarene. The [Ag4X4(P4)] complexes react with free P4 ligand to yield the [Ag2X2(P4)] or [AgX(P4)] complexes, which are characterized in solution by NMR spectroscopy to have a conformation opposite to that of the [Ag4X4(P4)] complexes; the silver(I) phosphinite groups are on the upright arene rings of the resorcinarene "boat" instead of the horizontal arene units. There is an easy equilibrium between these complexes. When X = triflate, the [Ag4X4(P4)] complexes disproportionate and add aqua ligands during slow crystallization to give "capsule complexes", which are characterized crystallographically as [Ag10(O3SCF3)10(OH2)6(P4)2], [Ag10(O3SCF3)6(OH2)8(P4)2][O3SCF3]4, or [Ag13(O3SCF3)13(OH2)7(P4)2] depending on the resorcinarene tetraphosphinite ligand P4 used. These unusual capsule complexes are formed by the tail-to-tail self-assembly of pairs of [Ag4(P4)]4+ units linked by additional silver ions that bind to the phenyl substituents of one resorcinarene through {Ag(eta2-C6H5)}+ binding and to the bridging triflate ligands, aqua ligands, or both of the other resorcinarene unit.

Journal Article↗
PubMed2005

Self-assembly of chiral coordination polymers and macrocycles: a metal template effect on the polymer-macrocycle equilibrium.

The self-assembly of racemic and enantiopure binaphthyl-bis(amidopyridyl) ligands 1,1'-C(20)H(12){NHC(=O)-4-C(5)H(4)N}(2), 1, and 1,1'-C(20)H(12){NHC(=O)-3-C(5)H(4)N}(2), 2, with mercury(II) halides (HgX(2); X = Cl, Br, I) to form extended metal-containing arrays is described. It is shown that the self-assembly can lead to homochiral or heterochiral polymers or macrocycles, through self-recognition or self-discrimination of the ligand units, and the primary materials can further self-assemble through hydrogen bonding between amide substituents. In addition, the formation of macrocycles or polymers can be influenced by the presence or absence of excess mercury(II) halide, through a template effect, and mercury(II) halide inclusion complexes may be formed. In one case, an unusual polymeric compound was obtained, with 1 guest HgX(2) molecule for every 12 mercury halide units in the polymer.

Journal Article↗
PubMed2005

Disilver(I) macrocycles: variation of cavity size with anion binding.

Reaction of the N-methylated bis(amidopyridine) ligand, LL = C6H4(1,3-CONMe-4-C5H4N)2, with the silver salts AgNO3, AgO2CCF3, AgO3SCF3, AgBF4, and AgPF6 gave the corresponding cationic disilver(I) macrocycles [Ag2(micro-LL)2]X2, 2a-e. The transannular silver...silver distance in the macrocycles varies greatly from 2.99 to 7.03 A, and these differences arise through a combination of different modes ofanion binding and from the presence or absence of silver...silver secondary bonding. In all complexes, the ligand adopts a conformation in which the methyl group and oxygen atom of the MeNCO units are mutually cis, but the overall macrocycle can exist in either boat (X = PF6 only) or chair conformation. Short transannular silver...silver distances are found in complexes 2b,c, in which the anions CF3CO2- and CF3SO3- bind above and below the macrocycle, but longer silver...silver distances are found for 2a,d,e, in which the anions are present, at least in part, inside the disilver macrocycle. Easy anion exchange occurs in solution, and studies using ESI-MS indicate that the anion binding to form [Ag2X(micro-LL)2]+ follows the sequence X = CF3CO2- > NO3- > CF3SO3-.

Journal Article↗
PubMed2004

A chiral [2]catenane self-assembled from meso-macrocycles of palladium(II).

Reaction of trans-[PdX2(SMe2)2](X = Cl or Br) with the chiral ligand LL = 1,1'-binaphthyl-2,2'-(NHC(= O)-3-C5H4N)2 gave the [2]catenane complexes trans-[{(PdX2)2(micro-LL)2}2], which are formed by self-assembly from 4 units each of trans-PdX2 and LL. The catenation is favored by the formation of multiple hydrogen bonds between the constituent macrocycles (4 x NHClPd, 2 x NHO double bond C). If the ligand LL is racemic, each macrocycle trans-[(PdX2)2(micro-LL)2] is formed in the meso form trans-[(PdX2)2(micro-R-LL)(micro-S-LL)] but the resulting [2]catenane is chiral as a direct result of the catenation step. This is the first time that this form of chiral [2]catenane has been observed. The enantiomers of the [2]catenane further self-assemble in the crystalline form, through secondary intermolecular PdX bonding, to form a racemic infinite supramolecular polymer of [2]catenanes.

Journal Article↗
PubMed2004

Macrocyclic and lantern complexes of palladium(II) with bis(amidopyridine) ligands: synthesis, structure, and host-guest chemistry.

The reactions of [PdCl2(NCPh)2] in a 1:1 ratio with the bis(amidopyridine) ligands LL=C6H3(5-R)(1,3-CONH-3-C5H4N)2 with R=H (1a) or R=t-Bu (1b) give the corresponding neutral dipalladium(II) macrocycles trans,trans-[Pd2Cl4(mu-LL)2], 2a and 2b, which crystallize from dimethylformamide with one or two solvent molecules as macrocycle guests. The reaction of [PdCl2(NCPh)2] with LL in a 1:2 ratio gave the cationic lantern complex [Pd2(mu-LL)4]Cl4, 3c (LL=1b), and the reaction in the presence of AgO2CCF3 gave the corresponding trifluoroacetate salts [Pd2(mu-LL)4](CF3CO2)4, 3a (LL=1a) and 3b (LL=1b). These lantern complexes exhibit a remarkable host-guest chemistry, as they can encapsulate cations, anions, and water molecules by interaction of the guest with either the electrophilic NH or the nucleophilic C=O substituents of the amide groups, which can be directed toward the center of the lantern through easy conformational change. The structures of several of these host-guest complexes were determined, and it was found that the cavity size and shape vary according to the ligand conformation, with Pd...Pd separations in the range from 9.45 to 11.95 A. Supramolecular ordering of the lanterns was observed in the solid state, through either hydrogen bonding or secondary bonding to the cationic palladium(II) centers. The selective inclusion by the lantern complexes of alkali metal ions in the sequence Na+ >> K+ >> Li+ was observed by ESI-MS.

Journal Article↗
PubMed2004

Self-assembly using dynamic coordination chemistry and hydrogen bonding: mercury(II) macrocycles, polymers and sheets.

The self-assembly of extended metal-containing arrays is described based on dynamic coordination chemistry at mercury(II) with bis(amidopyridyl) ligands to form macrocycles, polymers, or sheets which can be further organized by hydrogen bonding between amide substituents. The ligands 1,2-C6H4[NHC(O)-4-C5H4N]2, 1, 1,2-C(6)H(4)[C(O)NHCH(2)-4-C(5)H(4)N](2), 2, and 1,2-C(6)H(4)[CH(2)C(O)NHCH(2)-4-C(5)H(4)N]2, 3 can adopt polar conformations and so can confer helicity in their complexes. Several macrocycles of formula [(HgX(2))(2)(micro-LL)(2)] (LL = 1, 2), with tetrahedral mercury(II) centers, were prepared in which individual molecules are further self-assembled via hydrogen bonding in the solid state to form one- or two-dimensional polymers or sheets. In one case, a one-dimensional polymer [((HgX2)-(mu-3))n] was formed. It is shown that the mercury(II) centers can be six-coordinate in forming the sheet structure [((HgX2)(mu-2)2)n], in which there are particularly large pores.

Benzamides↗
PubMed2004

Engineering silver(I) coordination networks through hydrogen bonding.

The silver(I) coordination networks [Ag2(mu-O2CCF3)2(mu-NN)2](infinity) exist as a polymer of macrocycles or a double-stranded polymer when NN = 1,2-C6H4[NHC(O)-4-C5H4N]2 or 1,2-C6H4[NHC(O)-3-C5H4N]2, respectively. Crystal engineering of the polymers is achieved through interchain hydrogen bonds.

Journal Article↗
PubMed2003

Tetraphosphinitoresorcinarene complexes: cationic silver(I) and copper(I) halide complexes as mercurate(II) anion receptors.

The reactions of mercury(II) halides with the tetraphosphinitoresorcinarene complexes [P4M5X5], where M=Cu or Ag, X=Cl, Br, or I, and P4=(PhCH2CH2CHC6H2)4(O2CR)4(OPPh2)4 with R=C6H11, 4-C6H4Me, C4H3S, OCH2CCH, or OCH2Ph, have been studied. The reactions of the complexes with HgX2 when M=Ag and X=Cl or Br occur with elimination of silver(I) halide and formation of [P4Ag2X(HgX3)], but when M=Ag and X=I, the complexes [P4Ag4I5(HgI)] are formed. When M=Cu and X=I, the products were the remarkable capsule complexes [(P4Cu2I)2(Hg2X6)]. When M=Ag and X=I, the reaction with both CuI and HgI2 gave the complexes [P4Cu2I(Hg2I5)]. Many of these complexes are structurally characterized as containing mercurate anions weakly bonded to cationic tetraphosphinitoresorcinarene complexes of copper(I) or silver(I) in an unusual form of host-guest interaction. In contrast, the complex [P4Ag4I5(HgI)] is considered to be derived from an anionic silver cluster with an iodomercury(II) cation. Fluxionality of the complexes in solution is interpreted in terms of easy, reversible making and breaking of secondary bonds between the copper(I) or silver(I) cations and the mercurate anions.

Journal Article↗
PubMed2003

Tetraphosphinitoresorcinarene complexes: dynamic clusters with silver(I) and copper(I) halides.

Silver(I) and copper(I) halide derivatives of several tetrakis(diphenylphosphinito)resorcinarene ligands are reported. The complexes [resorcinarene(O(2)CR)(4)(OPPh(2))(4)(M(5)X(5))], with resorcinarene = (PhCH(2)CH(2)CHC(6)H(2))(4), R = C(6)H(11), 4-C(6)H(4)Me, C(4)H(3)S, OCH(2)CCH, or OCH(2)Ph, M = Ag, X = Cl, Br, or I, M = Cu, and X = Cl or I, contain a crownlike [P(4)M(5)X(5)] metal halide cluster. These crown clusters were found to be dynamic in solution, as studied by variable-temperature NMR, and easily fragment to give the corresponding complexes containing [P(4)M(4)X(5)](-) and [P(4)M(2)(micro-X)](+) units. Reaction of pentasilver crown clusters with triflic acid gave the corresponding disilver complexes [resorcinarene(O(2)CR)(4)(OPPh(2))(4)]Ag(2)(micro-Cl)]]CF(3)SO(3). Thus, these resorcinarene-based ligands act as a platform for the easy and reversible assembly of copper(I) and silver(I) clusters with novel structures.

Journal Article↗
PubMed2003

Structures and conformational dynamics of gold(I) halide complexes of resorcinarene tetraphosphinite ligands.

Gold(I) halide derivatives of several tetrakis(diphenylphosphinite) tetraester resorcinarene compounds have been prepared. The complexes are shown to exist in boat conformations, and two different boat conformations were characterized by X-ray structure determinations; the structural characterization of both boat conformations of the same parent resorcinarene is unprecedented. Intramolecular Au.Au interactions were observed in the solid state for both boat conformers and could cause twisting of the resorcinarene skeleton. Several of the complexes exist in solution as an equilibrium mixture of the two different boat conformers, and the equilibrium and dynamics of exchange were studied by variable-temperature NMR.

Journal Article↗