Christoph E. Strasser

Competitive bulk liquid membrane transport of some metal ions using RC(S)NHP(S)(OiPr)2 as ionophores. Unusual supramolecular “honeycomb” aggregate of the polynuclear copper(I) complex of H2NC(S)NHP(S)(OiPr)2

Competitive transport experiments involving metal ions from an aqueous source phase through a chloroform membrane into an aqueous receiving phase have been carried out using a series of N-(thio)phosphorylated (thio)amide and thiourea ligands as ionophores in the organic phase. The source phase contained equimolar concentrations of Co(II), Ni(II), Cu(II), Zn(II), Ag(I), Cd(II) and Pb(II) with the source and receiving phases being buffered at different pH. Good transport properties were observed for Ag(I) in the case of (13). The best extraction properties have been shown by (3)L(1), (3)L(8), (2)L(7), (3)L(9) and (3)L(11) which contain an unsubstituted nitrogen atom at the C[double bond, length as m-dash]S groups ((3)L(1) and (3)L(9)), or a third nitrogen atom, capable of participating in additional coordination ((3)L(8), (2)L(7) and (3)L(11)). Reaction of Cu(NO(3))(2).6H(2)O with the potassium salt of the N-thiophosphorylated thiourea NH(2)C(S)NHP(S)(OiPr)(2) formed a new supramolecular Cu(I) complex, [{Cu(6)((2)L(1))(6)}{Cu(3)((2)L(1))(3)}.4Me(2)CO] that contains both trinuclear and hexanuclear forms in its solid state structure, and in solution.

Fischer-type tungsten acyl (carbeniate), carbene and carbyne complexes bearing C5-attached thiazolyl substituents: interaction with gold(I) fragments

2-(1-Piperidinyl)thiazole and 2-phenylthiazole were deprotonated at C5 of the thiazole rings and both reacted with [W(CO)6] to form Fischer-type tungsten carbeniate complexes 1a and 1b of the type [(CO5)WC(O){}] (R = 1-piperidinyl for 1a and phenyl for 1b). Reaction of carbeniate 1b with [(Ph3P)AuCl] afforded by acyl ligand transfer a tungstenoxycarbene complex of gold(I), [(Ph3P)AuC{OW(CO)5}{}] (2), in which the W(CO)5 fragment remains coordinated to the acyl oxygen atom. Alkylation of 1a and 1b with [Me3O][BF4] afforded the carbene complexes [(CO)5WC(OMe){}], 3a and 3b. A rare example of a hydroxycarbene complex of 1a stabilised by a hydrogen bond to 1a, [NMe4][{}C{W(CO)5}OH...(O)C{W(CO)5}{}], 4, (R = 1-piperidinyl) was crystallised while attempting to prepare 3a by a different route. Reaction of 3b with [ClAu(tht)] (tht = tetrahydrothiophene) furnished the corresponding alkoxycarbene gold(I) complex [ClAuC(OMe){}], 5. Subsequent reaction of 1a and 1b with bis(trichloromethyl)carbonate and pyridine yielded the carbyne complexes [Cl(CO)2(py)2WC{}], 6a and 6b. Reaction of 6a with [ClAu(tht)] afforded an unstable addition compound, 7, in which the gold atom is coordinated to the formal carbyne triple bond. Interaction between gold and the proton of the thiazole ring in this complex was observed by variable temperature NMR. The crystal and molecular structures of complexes 1a, 1b, 2, 3b, 4, 5, 6a and 6b were all determined by single crystal X-ray diffraction.

Competitive bulk liquid membrane transport and solvent extraction of some metal ions using RC(S)NHP(X)(OiPr)2 (X = O, S) as ionophores. Formation of the polynuclear complex of [Ag(NC–NP(S)(OiPr)2)]n

Competitive transport experiments involving metal ions from an aqueous source phase through a chloroform membrane into an aqueous receiving phase have been carried out using a series of N-(thio)phosphorylated (thio)amide and thiourea ligands as the ionophore present in the organic phase. The source phase contained equimolar concentrations of Co(II), Ni(II), Cu(II), Zn(II), Ag(I), Cd(II) and Pb(II) with the source and receiving phases being buffered at a number of different pHs. Solvent extraction properties of the ligands towards the same metal cations under the same experimental conditions as for the transport were also studied. All ligands demonstrated 100% extraction of Ag(I). Reaction of AgNO(3) with the potassium salt of the N-thiophosphorylated thiourea NH(2)C(S)NHP(S)(OiPr)(2) gave a new supramolecular Ag(I) complex, [AgZ](n) (Z = {N[triple bond]C-NP(S)(OiPr)(2)}(-)) that contains both tri- and tetracoordinated Ag(I). The novel polynuclear Ag(I) complex [AgZ](n) described and structurally characterized by single crystal X-ray diffraction has no precedent.

Amides of gold(I) diphosphines prepared from N-heterocyclic sources and their in vitro and in vivo screening for anticancer activity

A series of new neutral mononuclear or dinuclear gold(I) complexes and a cyclic cationic tetranuclear amidogold(I) complex comprising of the phosphines 1,2-bis(dimethylphosphino)ethane (dmpe), μ-1,2-bis(diphenylphosphino)ethane (dppe), μ-1,3-bis(diphenylphosphino)propane (dppp), μ-1,5-bis(diphenylphosphino)pentane (dpppe), μ-1,6-bis(diphenylphosphino)hexane (dpph) or trimethylphosphine, and several N-heterocyclic ring systems (imidazolate, pyrazolate, 1,2,3-triazolate, 1,2,4-triazolate, pyrrolate, 9H-purine-9-ate or 9H-purine-6-amine-9-ate) as ligands, reveal intermolecular aurophilic interactions and 2D channels available for solvent molecules in some of their crystal structures. The antitumour activity of the acyclic gold(I) compounds is highly dependent on the substituents on the phosphorus atoms being highest for phenyl groups and lower for methyl groups. The activity of these compounds against selected cell lines is linked to the length of the carbon bridge between the two phosphorus atoms being highest with a bridge consisting of 5 or 6 carbons. Two compounds with the highest tumour specifities that contain dpppe and pyrazolate (a lipophilic compound) or 1,2,4-triazolate (a hydrophilic compound) induce an apoptotic cell death pathway and a maximum dose to Balb/C mice is tolerated.

Preparation of tris(azolyl)phosphine gold(I) complexes: digold(I) coordination and variation in solid state intermolecular interactions

Various tris(azolyl)phosphines R3P (R = 1-methylimidazol-2-yl, thiazol-2-yl, 4-methylthiazol-2-yl or 4,5-dimethylthiazol-2-yl) (1a–d) were utilised to prepare complexes of the type R3PAuCl (2a–d). The donor strength of the nitrogen atoms was assessed with natural-abundance 15N{1H} NMR of 1a–c and 2a–c. The chloride of 2c could be successfully substituted by the anions BzS– and NCS–. Further utilisation of the imine nitrogens of the tris(azole)phosphines to coordinate additional AuI centres was successful only for 2a where treatment with 3 mole equivalents of C6F5Au(tht) (tht = tetrahydrothiophene) afforded bis(pentafluorophenyl)-µ-[tris(1-methylimidazol-2-yl)phosphine-κ2P,N]digold(I) (4). A hydrolysis product consisting of two bis(1-methylimidazol-2-yl)phosphinite ligands bridging a Au24+ centre and further coordination to two AuC6F5 moieties (5) was formed during this reaction. The crystal and molecular structures were determined of compounds 1d, 2a–d and 3b. Intriguingly, 2b and 2c crystallise in a total of seven polymorphs and solvates exhibiting different modes of intermolecular association. Compound 2b crystallises in three polymorphs; two of them and the solvate 2b·0.5CH2Cl2 exhibit aurophilic interaction while the third one is stabilised by a short Au⋯Cl interaction of 3.2660(9) A. In 2c, one polymorph exhibits a strong aurophilic interaction of 3.0393(4) A, but the other, as well as the solvate 2c·thf, lack such contacts. Product 2b is the first simple gold compound known to have both Au⋯Au or Au⋯Cl contacts in different crystals. Calculations at the B3LYP and MP2 levels of theory using quasi-relativistic basis sets show that for 2b2 the Au⋯Cl interaction is between 2.6 and 12.2 kJ mol–1 greater than the Au⋯Au interaction, depending on the level of theory and basis set. This contrasts with a model (PH3AuCl)2 dimer, where the Au⋯Au interaction is found to be stronger.

Aerial oxidation of tetrahydrofuran to 2-hydroxotetrahydrofuran in the presence of a trimeric CuI complex [Cu3L3] (HL = tBuNHC(S)NHP(S)(OiPr)2) and trapping of the unstable product at recrystallization

The reaction of the potassium salt of N-thiophosphorylated thiourea tBuNHC(S)NHP(S)(OiPr)2 (HL) with Cu(NO3)2 in aqueous EtOH leads to the trinuclear [Cu3(tBuNHC(S)NP(S)(OiPr)2-S,S′)3] ([Cu3L3]) complex. It was established that [Cu3L3] provokes the aerobic oxidation of tetrahydrofuran to 2-hydroxotetrahydrofuran and traps the latter at crystallization.

Ligating properties of anionic Fischer-type carbene complexes, [(CO)(5)M[double bond, length as m-dash]C(X)Y](-).

With the simplest of anionic Fischer-type carbene complexes acting as ligands, Cp(2)Zr(Cl){OCMe}M(CO)(5) compounds (M = Cr or W) promote alpha-olefin oligomerization and polymerization in the presence of MAO. Attaching an N-heterocyclic ring to the carbene carbon atom in similar precursors, allows a variety of hard metal ions and fragments to be captured by external bidentate coordination. The outcome of the attachment of a phosphorus or sulfur functionality to an alpha-carbon of an O-anionic carbene is formation of a bidentate ligand and then internal four-membered carbene-heteroatom chelate formation. alpha-Deprotonated carbene complexes are also precursors for remote, one-N, six-membered carbene complexes of various metals whereas alpha-C-, alpha-N- or alpha-O-deprotonated as well as beta-deprotonated Fischer-type carbene complexes display unique synthon properties towards Ph(3)PAu(+) and partake in unusual ensuing coordination of liberated group 6 metal carbonyl moieties to form dinuclear products.

Bis[μ-1,2-bis­(diphenyl­phosphino)ethane-κ2P:P′]digold(I)(Au—Au) bis­(trifluoro­methane­sulfonate) acetonitrile disolvate

The title compound, [Au2(C26H24P2)2](CF3SO3)2·2CH3CN, comprises a cyclic cation with a short intramolecular aurophilic interaction of 2.9220 (3) Å. The trifluoromethanesulfonate anions and acetonitrile solvent molecules are located in channels formed by the complex cations that run along the crystallographic c axis. Each counter-anion is also engaged in a C—H⋯O contact with one of the methylene H atoms of a 1,2-bis(diphenylphosphino)ethane (dppe) ligand; another C—H⋯O contact involving an aromatic H atom is also observed.

4-Bromo-N-(diisopropoxyphosphor-yl)benzamide

In the title compound, C13H19BrNO4P, the crystal structure is stabilized by intermolecular N—H⋯O hydrogen bonds between the phosphoryl O atom and the amide N atom which link the molecules into centrosymmetric dimers. These dimers are further packed into stacks along the c axis by intermolecular C—H⋯O and C—H⋯π interactions.

18-Membered heterometallacyclic gold(I) compounds: Structural influences of co-crystallized solvent

5-Lithiated 4,4-dimethyl-2-(2-thienyl)oxazoline reacted by halide and tetrahydrothiophene (THT) substitution with [AuCl(THT)] to form a cyclic trinuclear compound (1) in satisfactory yield. Spectroscopic studies and single-crystal X-ray analyses clarified the bonding within the ring system. The structure determination of two THF solvates revealed differences in the supramolecular assembly of the constituting molecules. Graphical Abstract 18-Membered Heterometallacyclic Gold(I) Compounds: Structural Influences of Co-crystallized Solvent