μ-Pyrazine-2,5-dicarboxylato-bis[chlorido(η6-p-cymene)ruthenium(II)] tert-butanol disolvate

μ-Pyrazine-2,5-dicarboxylato-bis[chlorido(η6-p-cymene)ruthenium(II)] tert-butanol disolvat

Conductive PANI fibres and determining factors for the electrospinning window

Polyaniline doped with CSA / PEO conductive nanofibres were produced by electrospinning. The electrospinning window was determined by using a three level, full factorial experimental design. The combined effects of the humidity, voltage and flow rate on the fibre morphology and diameter were examined demonstrating that the ambient humidity is the critical factor affecting the electrospinning process and determining the electrospinning window for a conductive polymer. Low humidity favors the formation of defect free fibres while high humidity either hinders fibre formation or causes the formation of defects on the fibres either due to jet discharge or due to water absorption and phase separation. High level of doping with CSA led to the formation of crystalline structures. Data fitting was used to explore the behavior of conductive polymers in electrospinning and very good agreement between experimental and theoretical predictions was obtained for only a limited range of experimental conditions, whereas deviation was observed for all other sets of conditions

New (aminomethyl)phosphines via selective hydrophosphination and/or phosphorus based Mannich condensation reactions

Controlled stepwise reaction of a geminal substituted alkene or primary amine group afforded a small library of new functionalised tertiary and ditertiary phosphines. Accordingly, Mannich based condensation of the commercially available disubstituted arene C 6 H 4 (NH 2 ){2-C(Me)=CH 2 } with HOCH 2 PR 2 (R 2 = Cg: 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phosphaadamantyl; Ph 2 ) afforded the (aminomethyl)phosphines C 6 H 4 (NHCH 2 PCg){2-C(Me)=CH 2 } L 1 and C 6 H 4 (NHCH 2 PPh 2 ){2-C(Me)=CH 2 } L 2 in approx. 60% yield. In addition to the formation of L 2 , the diphosphine L 3 was also identified and independently synthesised upon reaction of C 6 H 4 (NH 2 ){2-C(Me)=CH 2 } with two equiv. of HOCH 2 PPh 2 in CH 3 OH under reflux. Alternatively, reaction of C 6 H 4 (NH 2 ){2-C(Me)=CH 2 } with H-PR 2 (R 2 = Cg or Ph 2 ) in the presence of AIBN [2,2′-azobis(2-methylpropionitrile)] as free radical initiator, afforded the primary amine functionalised phosphines C 6 H 4 (NH 2 ){2-CH(Me)CH 2 PCg} L 4 and C 6 H 4 (NH 2 ){2-CH(Me)CH 2 PPh 2 } L 5 in 85% and 66% isolated yields respectively. In both cases only the anti-Markovnikov addition products were observed. Subsequent reaction of L 5 with HOCH 2 PR 2 (R 2 = Ph 2 ) afforded the unsymmetrical ditertiary phosphine C 6 H 4 (NHCH 2 PPh 2 ){2-CH(Me)CH 2 PPh 2 } L 6 . Some preliminary coordination studies towards [RuCl(μ-Cl)(η 6 -C 10 H 14 )] 2 [AuCl(tht)] (tht = tetrahydrothiophene) and [MCl 2 (η 4 -cod)] (M = Pd, Pt; cod = cycloocta-1,5-diene) demonstrate these new ligands behave as classic P-donors leaving the pendant amino or alkenyl groups non-coordinating. All compounds have been characterised by multinuclear NMR, FT−IR, mass spectrometry and microanalysis. Single crystal X-ray studies have been performed on L 3 , L 5 , L 6 , 1, 3b·0.5CH 2 Cl 2 , 4a·1.5CH 2 Cl 2 , 5 and 6·0.5CDCl 3 ·0.5C 4 H 10 O

Unusual metal-coordinated zwitterionic P-C-N-C-N-C phosphido adducts

Rare examples of homodinuclear zwitterionic PdII and PtII complexes with bridging, two-coordinate P{cyclo-CH2N(R)CHN- (R)CH2} ligands (R = 4-FC6H4CH2, C6H5CH2) have been characterized by single-crystal X-ray diffraction using synchrotron radiation. Short N-C distances and enlarged N-C-N bond angles support electron delocalization in the central N-C-N backbone

Intramolecular hydrogen-bonded tertiary phosphines as 1,3,5-triaza-7-phosphaadamantane (PTA) analogues

New cationic trialkylphosphines [P(CH2NH2R){CH2N(R)CH2N(R)CH2}]+ (R ) C6H5CH2, a; 4-FC6H4CH2, b), as their Cl- (1a, 1b), SbF6 - (2a, 2b), and PF6 - (3a, 3b) salts, are described. The phosphine framework is conformationally locked, in the solid state, through pairs of intramolecular N-H · · · N hydrogen bonds which are maintained in the RuII and RhIII complexes 4 and 5. Phosphines 1a-3b can be considered as charged variants of the well-known PTA ligand

Versatile routes to selenoether functionalised tertiary phosphines

New selenoether functionalised tertiary phosphines, based on aryl (2a, 2b) or alkyl (4) backbones, have been synthesised and characterised. P,Se-chelation has been achieved upon complexation to square-planar PtII (3a) or PdII (3b) metal centres. For 3a and 3b, weak non-covalent M◊ ◊ ◊ Se contacts were established using single crystal X-ray crystallography

The backbone of success of P,N-hybrid ligands: some recent developments

Organophosphorus ligands are an invaluable family of compounds that continue to underpin important roles in disciplines such as coordination chemistry and catalysis. Their success can routinely be traced back to facile tuneability thus enabling a high degree of control over, for example, electronic and steric properties. Diphosphines, phosphorus compounds bearing two separated PIII donor atoms, are also highly valued and impart their own unique features, for example excellent chelating properties upon metal complexation. In many classical ligands of this type, the backbone connectivity has been based on all carbon spacers only but there is growing interest in embedding other donor atoms such as additional nitrogen (–NH–, –NR–) sites. This review will collate some important examples of ligands in this field, illustrate their role as ligands in coordination chemistry and highlight some of their reactivities and applications. It will be shown that incorporation of a nitrogen-based group can impart unusual reactivities and important catalytic applications

Mild intramolecular P–C(sp3) bond cleavage in bridging diphosphine complexes of RuII RhIII and IrIII

Three new carboxylic acid functionalised diphosphines, R2PCH2N(Ar)CH2PR2 [CyL1 R = Cy, Ar = (1-CO2H)(3-OMe)C6H3, CyL2R = Cy, Ar = (1-CO2H)(3-OH)C6H3 and PhL3 R = Ph, Ar = (1-CO2H)(5-OMe)C6H3] have been prepared from condensation of R2PCH2OH and the appropriate aromatic amine in MeOH, and isolated as colourless solids (for CyL1, CyL2) in good yield. Reaction of CyL1, CyL2, or PhL3, along with the previously reported diphosphines PhL1, PhL2, and PhL4, and [RuCl(μ-Cl)(η6-Me2CHC6H4Me)]2 in CH2Cl2 affords the P/P-bridging dinuclear ruthenium(II) complexes {RuCl2(η6-Me2CHC6H4Me)}2(μ-CyL1−PhL4) 1a−f as red/orange solids. Careful monitoring by 31P{1H} NMR spectroscopy of CDCl3 solutions of 1a−e revealed remarkably clean P−Csp3 bond cleavage to give RuII mononuclear species 2a−e and the known secondary phosphine complexes RuCl2(η6-Me2CHC6H4Me)(PCy2H) 3 and RuCl2(η6-Me2CHC6H4Me)(PPh2H) 4. Furthermore, facile P−Csp3 bond cleavage of PhL1 can be observed using the chloro-bridged dimers [IrCl(μ-Cl)(η5-C5Me5)]2 or [RhCl(μ-Cl)(η5-C5Me5)]2 instead. Deuterium labelling of CyL1, CyL1, PhL1, and PhL2 enabled the assignment of the methylene protons to be confirmed from 1H NMR spectroscopy. All new compounds have been characterised using a range of spectroscopic and analytical techniques. Single crystal X-ray structures have been determined for CyL1, 1d·3OEt2, 1f·2CDCl3·OEt2, 2b, 2c, 2d·CDCl3, 2e·0.5OEt2 and 6b·1.5CDCl3. The free phenolic group in CyL1, 1d·3OEt2, 1f·2CDCl3·OEt2, 2b and 2d·CDCl3 participates in intra- or intermolecular O−H···O hydrogen bonding. </p

Low-dimensional architectures in isomeric <i>cis</i>-PtCl₂{Ph₂PCH₂N(Ar)CH₂PPh₂} complexes using regioselective-N(aryl)-group manipulation

The solid-state behaviour of two series of isomeric, phenol-substituted, aminomethylphosphines, as the free ligands and bound to PtII, have been extensively studied using single crystal X-ray crystallography. In the first library, isomeric diphosphines of the type Ph2PCH2N(Ar)CH2PPh2 [1a–e; Ar = C6H3(Me)(OH)] and, in the second library, amide-functionalised, isomeric ligands Ph2PCH2N{CH2C(O)NH(Ar)}CH2PPh2 [2a–e; Ar = C6H3(Me)(OH)], were synthesised by reaction of Ph2PCH2OH and the appropriate amine in CH3OH, and isolated as colourless solids or oils in good yield. The non-methyl, substituted diphosphines Ph2PCH2N{CH2C(O)NH(Ar)}CH2PPh2 [2f, Ar = 3-C6H4(OH); 2g, Ar = 4-C6H4(OH)] and Ph2PCH2N(Ar)CH2PPh2 [3, Ar = 3-C6H4(OH)] were also prepared for comparative purposes. Reactions of 1a–e, 2a–g, or 3 with PtCl2(η4-cod) afforded the corresponding square-planar complexes 4a–e, 5a–g, and 6 in good to high isolated yields. All new compounds were characterised using a range of spectroscopic (1H, 31P{1H}, FT–IR) and analytical techniques. Single crystal X-ray structures have been determined for 1a, 1b∙CH3OH, 2f∙CH3OH, 2g, 3, 4b∙(CH3)2SO, 4c∙CHCl3, 4d∙½Et2O, 4e∙½CHCl3∙½CH3OH, 5a∙½Et2O, 5b, 5c∙¼H2O, 5d∙Et2O, and 6∙(CH3)2SO. The free phenolic group in 1b∙CH3OH, 2f∙CH3OH,2g, 4b∙(CH3)2SO, 5a∙½Et2O, 5c∙¼H2O, and 6∙(CH3)2SO exhibits various intra- or intermolecular O–H∙∙∙X (X = O, N, P, Cl) hydrogen contacts leading to different packing arrangements

Flexible kappa(4)-PNN ' O-tetradentate ligands: synthesis, complexation and structural studies

The three-step synthesis of new, air-stable, PNN′O-tetradentate ligands 3a·HH–3c·HH by Schiff base condensation of the 1° amines 2a–2c with 2-Ph2PC6H4(CHO) in refluxing EtOH is described. The racemic ligand 3d·HH, isolated in 79% yield, was successfully prepared from 2-C6H4(OH){C(O)NHCH2CH(Me)NH2} 2d and 2-Ph2PC6H4(CHO) in absolute EtOH... cont'd