Synthesis and crystal structure of sodium (ethane-1,2-di-yl)bis-[(3-meth-oxy-prop-yl)phosphinodi-thiol-ate] octa-hydrate.

The title compound, -poly[[tri-aqua-sodium]-di-μ-aqua-[tri-aqua-sodium]-μ-(ethane-1,2-di-yl)bis-[(3-meth-oxy-prop-yl)phosphinodi-thiol-ato]], [Na(CHOPS)(HO)] , crystallizes in the triclinic space group 1. The dianionic [CHO(CH)P(=S)(S-)CHCHP(=S)(S-)(CH)OCH] ligand fragments are joined by a dicationic [Na(HO)] cluster that includes the oxygen of the meth-oxy-propyl unit of the ligand to form infinite chains.

Solvent Cage Effects: A Comparison of Geminate and Nongeminate Radical Cage Pair Combination Efficiencies.

This study measured and compared the combination efficiencies () of geminate radical cage pairs to nongeminate (collisional) radical cage pairs ('). For the [Cp'(CO)Mo·, ·Mo(CO)Cp'] radical cage pair, ' was found to be smaller than in solutions having the same viscosity. It is proposed that the difference in and ' arises because the radicals in the collisional cage pair are less likely to have the correct orbital orientation for radical-radical combination to occur, whereas photochemically generated geminate cage pairs are more likely to have the correct orbital orientation.

Radical Cage Effects: The Prediction of Radical Cage Pair Recombination Efficiencies Using Microviscosity Across a Range of Solvent Types.

This study reports a method for correlating the radical recombination efficiencies (F) of geminate radical cage pairs to the properties of the solvent. Although bulk viscosity (macroviscosity) is typically used to predict or interpret radical recombination efficiencies, the work reported here shows that microviscosity is a much better parameter. The use of microviscosity is valid over a range of different solvent system types, including nonpolar, aromatic, polar, and hydrogen bonding solvents.

Radical Cage Effects: Comparison of Solvent Bulk Viscosity and Microviscosity in Predicting the Recombination Efficiencies of Radical Cage Pairs.

This study reports the results of experiments that probed how solvents affect the recombination efficiency (FcP) of geminate radical cage pairs. The macroviscosity of solvents has traditionally been used to make quantitative predictions about FcP, but experiments reported here show that FcP varies dramatically for solvent systems with identical macroviscosities. Experiments show that FcP correlates with the solvent microviscosity: five different solvent systems (consisting of a solvent and a structurally similar viscogen) were examined, and FcP was the same for all five solvent systems at any particular microviscosity.

Synthesis of tetraphosphine macrocycles using copper(i) templates.

The synthesis of phosphine macrocycles is a relatively underdeveloped area and no standard synthetic routes have emerged. Accordingly, two general synthetic routes to tetradentate phosphine macrocycles were investigated. Both routes use Cu(i) ions as template ions because, unlike other metals such as Pd(ii) and Pt(ii), the Cu(i) ions can be removed from the macrocyclic complex without degrading the macrocycle ligand.

Steric and Electronic Influences of Buchwald-Type Alkyl-JohnPhos Ligands.

The electron-donating and steric properties of Buchwald-type ligands ([1,1'-biphenyl-2-yl]dialkylphosphine; R-JohnPhos, where R = Me, Et, (i)Pr, Cy, (t)Bu) were determined. The π-acidity and σ-donating properties of the R-JohnPhos ligands were quantified using a Cotton-Kraihanzel analysis of the Cr(0)(CO)5(R-JohnPhos) complexes. Somewhat surprisingly, the σ-donating abilities of the R-JohnPhos ligands follow the trend (t)Bu-JohnPhos < Et-JohnPhos < (i)Pr-JohnPhos < Cy-JohnPhos ≪ Me-JohnPhos.

The synthesis of heteroleptic phosphines.

Heteroleptic phosphines (R2PR(1)) are a class of essential ligands for inorganic and organometallic chemistry. However, the syntheses of these phosphines are often fraught with laborious synthetic hurdles. Consequently, a renewed interest in innovative synthetic methods to access heteroleptic phosphines is emerging.

Crystal structure of trans-dihydrido-bis[tris-(di-methyl-amino)-phosphane-κP]platinum(II).

The mol-ecule of the title compound, [PtH2(C6H18N3P)2], has a centrosymmetric square-planar structure in which the Pt(II) atom is bonded to two H and two P atoms in a mutually trans configuration. The Pt(II) atom sits on an inversion center and thus the asymmetric unit contains only half the mol-ecule. The Pt-P and Pt-H distances are 2.

Benzyl-tris-[2-(di-benzyl-amino)-eth-yl]ammonium iodide.

In the title quaternary ammonium salt, C55H61N4 (+)·I(-), all three N,N-di-benzyl-ethanamine, -(CH2)2N(CH2C6H5)2, groups have different conformations. The N-C-C-N torsion angles are significantly different [89.86 (13), 162.

Characterization of an intermediate in the ammonia-forming reaction of Fe(DMeOPrPE)2N2 with acid (DMeOPrPE = 1,2-[bis(dimethoxypropyl)phosphino]ethane).

The reactivity of Fe(DMeOPrPE)2N2 with water and acid was explored. (DMeOPrPE is the bidentate phosphine 1,2-[bis(dimethoxypropyl)phosphino]ethane.) The complex reacts with acid to form trans-[Fe(DMeOPrPE)2(N2)H](+) and small amounts of ammonia and hydrazine.

Dichlorido(η(6)-p-cymene)(eth-oxy-diphenyl-phosphane)ruthenium(II).

The title compound, [RuCl2(C10H14)(C14H15OP)], is an Ru(II) complex in which an η(6)-p-cymene ligand, two chloride anions and the P atom of an ethoxydiphenylphosphane ligand form a piano-stool coordination environment about the central Ru(II) atom.

P,P'-Diphenyl-ethyl-enediphosphinic acid dihydrate.

The title compound, C(14)H(16)O(4)P(2)·2H(2)O, possesses a crystallographic inversion center where two -P(=O)(OH)(C(6)H(5)) groups are joined together via two -CH(2) groups. In the crystal, the acid molecules are linked by the water molecules via O-H⋯O hydrogen bonds, leading to the formation of a two-dimensional network lying parallel to (101).

Bis{1,2-bis-[bis-(3-meth-oxy-prop-yl)phosphan-yl]ethane-κP,P'}dichlorido-osmium(II).

In the centrosymmetric title compound, [OsCl(2)(C(18)H(40)O(4)P(2))(2)], the Os(II) atom adopts a trans-OsCl(2)P(4) geometry, arising from its coordination by two chelating diphosphane ligands and two chloride ions. One of the meth-oxy side chains of the ligand is disordered over two orientations in a 0.700 (6):0.

Coordination of a complete series of N2 reduction intermediates (N2H2, N2H4, and NH3) to an iron phosphine scaffold.

The series of dinitrogen reduction intermediates (N(2)H(2), N(2)H(4), and NH(3)) coordinated to the Fe(DMeOPrPE)(2)H(+)(DMeOPrPE = 1,2-[bis(dimethoxypropyl)phosphino]ethane) scaffold has been synthesized or generated. The synthesis of trans-[Fe(DMeOPrPE)(2)(NH(3))H][BPh(4)] and generation of trans-[Fe(DMeOPrPE)(2)(N(2)H(4))H][BPh(4)] were achieved by substitu tion of the dinitrogen ligand on trans-[Fe(DMeOPrPE)(2)(N(2))H][BPh(4)]. The trans-[Fe(DMeOPrPE)(2)(N(2)H(2))H](+) complex and its deprotonated conjugate base, trans-Fe(DMeOPrPE)(2)(N(2)H)H, were observed by (31)P and (1)H NMR from decomposition of trans-[Fe(DMeOPrPE)(2)(N(2)H(4))H](+) in the presence of excess hydrazine.

Reactions of coordinated hydroxymethylphosphines with NH-functional amines: the phosphorus lone pair is crucial for the phosphorus Mannich reaction.

Non-coordinated hydroxymethylphosphines react readily with primary and secondary amines by the phosphorus Mannich reaction. To determine if this reactivity can be used to synthesize phosphine macrocycles, trans-Fe(DHMPE)(2)Cl(2) (DHMPE = 1,2-bis(dihydroxymethylphosphino)ethane) was prepared and reacted with various amines. However, no phosphorus Mannich reactivity was observed.

A colorimetric proton sponge.

1,8-Bis(dimethylamino)naphthalene ("Proton Sponge") and bromomaleic anhydride react quickly at room temperature, generating 3-(4,5-bis(dimethylamino)napthalen-1-yl)furan-2,5-dione (4-maleicanhydridoproton sponge or "MAPS"). MAPS is a deep purple solid that exhibits positive solvatochromism in solution. It is a weaker base than Proton Sponge.

Precursors to dinitrogen reduction: structures and reactivity of trans-[Fe(DMeOPrPE)2(eta(2)-H2)H]+ and trans-[Fe(DMeOPrPE)2(N2)H]+.

trans-[Fe(DMeOPrPE)(2)(H(2))H](+) and trans-[Fe(DMeOPrPE)(2)(N(2))H](+) (DMeOPrPE = 1,2-bis(dimethoxypropylphosphino)ethane) were synthesized and their structures determined by X-ray crystallography. These complexes are important species in a dinitrogen reduction scheme involving protonation of an iron(0) dinitrogen complex to produce ammonia. The rates of substitution of the coordinated H(2) and N(2) molecules with acetonitrile were monitored in a variety of organic solvents.

2,2'-(Propane-2,2-di-yl)dibenzothia-zole.

The two symmetry-independent mol-ecules in the asymmetric unit of the title compound, C(17)H(14)N(2)S(2), have similar geometry; the dihedral angles between the least-squares planes of the benzothia-zole groups in the two mol-ecules are 83.93 (3) and 81.26 (3)°.

trans-Bis{1,2-bis-[bis-(2-methoxy-ethyl)phosphino]ethane}dichloridoiron(II).

The Fe atom in the title compound, [FeCl(2)(C(14)H(32)O(4)P(2))(2)], has a distorted octa-hedral coordination with four P atoms in equatorial positions and two Cl atoms in apical positions.

Bis{1,2-bis-[bis-(3-hydroxy-prop-yl)phosphino]ethane}dichloridoiron(II).

In the title compound, [FeCl(2)(C(14)H(32)O(4)P(2))(2)], the Fe(II) atom (site symmetry ) adopts a distorted trans-FeCl(2)P(4) octa-hedral geometry with two P,P'-bidentate ligands in the equatorial positions and two chloride ions in the axial positions. In the crystal, mol-ecules are linked by O-H⋯O and O-H⋯Cl hydrogen bonds, generating a three-dimensional network.

Investigation of the reactivity of Pt phosphinito and molybdocene nitrile hydration catalysts with cyanohydrins.

Aldehyde- and ketone-derived cyanohydrins were reacted with the nitrile hydration catalysts [PtCl(PR(2)OH){(PR(2)O)(2)H}] (1) and Cp(2)Mo(OH)(OH(2))(+) (2) under a variety of hydration reaction conditions. In general, the cyanohydrins were hydrated to the amides rather slowly using these catalysts, but no subsequent hydrolysis of the amide products occurred. Catalyst 2 was much less reactive than catalyst 1, showing at best trace amounts of amide product.

Intermediates in the reduction of N(2) to NH(3): synthesis of iron eta(2) hydrazido(1-) and diazene complexes.

Iron complexes containing hydrazido(1-) and diazene ligands were investigated as potential intermediates in the reduction of N(2) to NH(3). Generation of cis-[Fe(DMeOPrPE)(2)(eta(2)-N(2)H(3))](+) and cis-Fe(DMeOPrPE)(2)(eta(2)-N(2)H(2)) (DMeOPrPE = 1,2-bis(dimethoxypropylphosphino)ethane) was achieved by addition of base to cis-[Fe(DMeOPrPE)(2)(N(2)H(4))](2+). The hydrazine, hydrazido(1-), and diazene complexes can be interconverted by protonation/deprotonation reactions.

Aqueous coordination chemistry of H2: why is coordinated H2 inert to substitution by water in trans-Ru(P2)2(H2)H+-type complexes (P2 = a chelating phosphine)?

The reactivity of a series of trans-Ru(P(2))(2)Cl(2) complexes with H(2) was explored. The complexes reacted with H(2) via a stepwise H(2) addition/heterolysis pathway to form the trans-[Ru(P(2))(2)(H(2))H](+) dihydrogen complexes. Some of the resulting eta(2)-H(2) complexes were surprisingly inert to substitution by water, even at concentrations as high as 55 M; however, the identity of the bidentate phosphine ligand greatly influenced the lability of the coordinated eta(2)-H(2) ligand.

Theoretical studies of N2 reduction to ammonia in Fe(dmpe)2N2.

Electronic structure calculations using density functional theory were performed on potential intermediates in the reaction of Fe(dmpe)(2)N(2) (dmpe = 1,2-bis(dimethylphosphino)ethane) with protons. Three mechanisms were investigated and compared, and the possibility of a two-electron reduction by a sacrificial Fe(dmpe)(2)N(2) complex was considered in each mechanism. A Chatt-like mechanism, involving the stepwise addition of protons to the terminal nitrogen, was found to be the least favorable.

trans-Bis(acetonitrile-κN)bis-{1,2-bis-[bis-(3-hydroxy-prop-yl)phosphino]ethane-κP,P'}iron(II) dichloride.

In the title compound, [Fe(CH(3)CN)(2)(C(14)H(32)O(4)P(2))(2)]Cl(2), the Fe(II) atom lies on a crystallographic inversion center and has a distorted trans-FeN(2)P(4) octa-hedral coordination environment arising from two P,P'-bidentate 1,2-bis-[bis-(3-hydroxy-prop-yl)phosphino]ethane ligands in the equatorial plane and two acetonitrile mol-ecules in the axial positions. One of the pendant -(CH(2))(3)OH groups of the ligand is disordered over two sets of sites in a 0.597 (5):0.