Alan A. Pinkerton

Dithiophosphinate Complexes of the Actinides. II. Preparation and Characterisation of the Compounds UO2(S2PR2)2·R'OH, [Et4N][UO2(S2PR2)2Cl] and UO2(S2PR2)2·Me3PO. The Crystal Structures of UO2(S2PR2)2·EtOH, R = Ph and C6H11, [Et4N][UO2(S2PR2)2Cl], R = Me and Ph, and UO2(S2PMe2)2·Me3PO

Abstract Salts of dithiophosphinic acids, R 2 PS 2 H, react with UO 2 Cl 2 in alcoholic, R′OH, solution to yield the complexes UO 2 (S 2 PR 2 ) 2 · R′OH. In the presence of excess chloride ion the alcohol is displaced to form the anionic chloro-complexes, which may be isolated as their [Et 4 N] + salts. Similar reactions with UCl 4 in the air yield the same compounds in a novel double oxidation reaction. The initially formed U(IV) complexes are rapidly oxidised by the air to yield the corresponding uranyl compound and, at the same time, two ligands are oxidised to form the dimer, [R 2 PS 2 ] 2 . When [UCl 6 ] 2− is employed, only the chlorocomplexes are obtained. The complexes for R = Me, Et, Pr i , OMe, OEt, OPr i , Ph and C 6 H 11 have been characterised by elemental analysis, IR and NMR spectroscopy. From one reaction of UVl 4 and NaS 2 PMe 2 , the complex UO 2 (S 2 PMe 2 ) 2 · Me 3 PO was obtained by an unknown route. The crystal structures have been determined for two alcohol adducts, two chlorocomplexes and the phosphine oxide adduct. UO 2 (S 2 PPh 2 ) 2 · EtOH: Triclinic, a = 11.589(2), b = 11.6928(8), c = 13.273(2) A , α = 113.205(8), β = 110. 849(9), γ = 92.979(9)°, P 1 , R = 0.057. UO 2 {S 2 P(C 6 H 11 ) 2 } 2 · EtOH: Monoclinic, a = 12.765(1), b = 16.502(2), c = 15.813(2) A , β = 90.622(9)°, P2 1 /n, R = 0.044. [Et 4 N][UO 2 (S 2 PMe 2 ) 2 Cl]: Orthorhombic, a = 10.770(1), b = 11.730(2), c = 20.079(2) A , P2 1 2 1 2 1 , R = 0.033. [Et 4 N][UO 2 (S 2 PPh 2 ) 2 Cl]: Monoclinic, a = 11.341 (2), b = 20.889(30, c = 16.172(2) A , β = 101.79(1)°, P2 1 /n, R = 0.046. UO 2 (S 2 PMe 2 ) 2 · Me 3 PO: Orthorhombic, a = 11.499 910, b = 13.079(1), c = 14.362(1) A , Pcmn, R = 0.050. All five complexes have pentagonal bipyramidal structures. The pentagonal plane contains four sulphur atoms from the two bidentate dithiophosphinate ligands (US = 2.873 A ) and one oxygen or chlorine atom from the coordinated ethanol (US = 2.41 A ), phosphine oxide (US = 2.32 A ) or chloride (US = 2.677 A ). The uranyl group is linear (US = 1.76 A ) and perpendicular to the equatorial plane. In both ethanol adducts the ethyl groups of the alcohol are disordered. The phosphine oxide adduct has crystallographic m symmetry. No more than two bidentate ligands could be attached to the uranium; however, a fifth equatorial coordination site is always occupied by an additional ligan, even when the substituents at phosphorus are bulky.

Stereospecific functionalisations of iron carbonyl complexes of 5,6,7,8-tetrakis(methylene)bicyclo[2.2.2]oct-2-ene. Crystal and molecular structure of (C12H12)Fe2(CO)6

Abstract When the reaction between an excess of Fe 2 (CO) 9 and the pentaene 5,6,7,8-tetrakis(methylene)bicyclo[2.2.2]oct-2-ene(I) is carried out in hexane/methanol the endo,exo -bis(tetrahaptotricarbonyliron) isomer (C 12 H 12 )Fe 2 (CO) 6 (IIa)is the major product. The structure of this complex has been determined by X-ray diffraction.The asymmetric positions of the two Fe(CO) 3 groups with respect to the roof-shaped organic skeleton was used to induce either stereo-specific functionalisation of the uncoordianted endocyclic CC double bond or stereo-and regiospecific functionalisation of one of the two coordinated s-cis -butadiene groups of the pentaene. Thus, hydroboration/oxidation of Ila gave the endo-exo -bis(tetrahaptotricarbonyliron)isomer of 5,6,7,8-tetrakis(methylene)bicyclo[2.2.2]octane-2-ol (IV). cis deuteration of the exocyclic double bond was achieved by treating IIa with D 2 /PtO 2 in n-hexane. Protonation of IIa by HCl/AlCl 3 /CH 2 Cl 2 to give the η 4 -diene : η 2 -ene : η 3 -dienyl cationic complex Va, followed by quenching of Va with NaHCO 3 /CH 3 OH, resulted in a 1,4-addition of methanol to one coordinated s-cis -butadiene system. In contrast, quenching with NaOCH 3 /CH 3 OH resulted in the corresponding 1,2-addition of methanol. This gave the η 4 -1,3-diene : η 4 -1,4-diene complex VIIIa in which, suprisingly, one Fe(CO) 3 group is coordinated to two CC double bonds in gauche positions with respect to each other.

Crystal structure and reactivity in solution of o-cyanobenzylbis(diphenylphosphino)ethyleneplatinum(II) tetrafluoroborate

Abstract X-ray analysis of crystalline o-cyanbenzylbis(dihenylphosphino)ethyleneplatinum(II) tetrafluoroborate shows that the complex is a dimer [Pt(o-CH2C6H4CN)(Ph2PCHCHPPh2)]22 (BF42 having linear PtNC bonds, even though molecular models indicate a favourable geometry for π-coordination of the nitrile moiety. The CN group remains σ-coordinated to the metal in solution and is very prone to nucleophilic attack by water, alcohols and amines, giving imide, iminoether and amidine complexes, respectivelly.

Ligand displacement from tetrakis(OO′-diethyl phosphorodithioate)-lanthanoid(III) anions by triphenylphosphine oxide. X-ray crystal structure of [La{S2P(OEt)2}3(POPh3)2] and [Sm{S2P(OEt)2}2(POPh3)3][S2P(OEt)2]

Triphenylphosphine oxide reacts with the anionic complexes [Ln{S2P(OEt)2}4]–(Ln = La–Lu, excluding Pm and Y) in ethanolic solution to displace one (La–Pr) or two (Nd–Lu and Y) ligands and form the neutral complexes [Ln{S2P(OEt)2}3(POPh3)2] or the cationic complexes [Ln{S2P(OEt)2}2(POPh3)2]+. The crystal structures of the lanthanum and samarium compounds have been determined.The lanthanum compound crystallises in space group P21/c with a= 19.66(2), b= 12.54(1), c= 24.11 (3)A, β= 94.16(8)°, and Z= 4, and the samarium compound in space group P21, with a= 17.90(2), b= 16.84(1)c= 12.54(2)A, β= 99.98(10)°, and Z= 2. Both structures were solved by conventional Patterson and Fourier, methods and refined to R 0.09 (La) and 0.08 (Sm).The neutral lanthanum complex has a square antiprismatic structure. The cationic samarium complex has a pentagonal bipyramidal structure. The nature of the bonding is discussed.

Iron carbonyl complexes of 2,3,5,6-tetrakis(methylene)-7-oxabicyclo[2.2.1]heptane. Crystal and molecular structure of (C10H10O)Fe(CO)3 and (C9H10CO)Fe2(CO)6

The reaction of 2,3,5,6-tetrakis(methylene)-7-oxabicyclo[2.2.1]heptane (I) with iron carbonyls in various solvents yields the (η 4 -1,3-diene)Fe(CO) 3 isomers (II: exo ; III: endo ) and the bimetallic isomers bis[(η 4 -1,3-diene)Fe(CO) 3 ] (IV: bis( exo ); V: endo,exo ). In weakly coordinating solvents, a parallel rearrangement of I occurs through CO bond cleavage of the allylic ether by Fe 2 (CO) 9 yielding an unsaturated ketone (VI) bonded to two Fe(CO) 3 groups through a trimethylenemethane and a 1,3-diene system, respectively. The geometries of III and VI have been ascertained by X-ray crystal structure determinations.

Iron and ruthenium carbonyls of 6,7-dimethylene-exo-3-oxatricyclo[3.2.1.02.4]octane. Protic acid additions to an epoxide ring homoconjugated to a η4-(diene)Fe(CO)3 function. Crystal structures of (C9H10O)Fe(CO)3 and (C10H14O2)Fe(CO)3

Abstract The reaction of the epoxydiene 6,7-dimethylene-exo-3-oxatricyclo[3.2.1.02.4]octane (I) with iron and ruthenium carbonyls in various solvents yields the (η4-1,3-diene)M(CO)3exo (II, M = Fe; IV, M = Ru). Theendo-Fe(CO)3 isomer (III) was obtained only in small yield from the reaction of I with Fe2(CO)9 or Fe(CO)5 in n-pentane. The exo configuration of II was ascertained by an X-ray crystal structure determination. It reacts cleanly and rapidly with HCl in ether giving theexo-2-chloro-5,6-dimethylene-syn-7-norbornanol-endo-iron tricarbonyl complex (V), while theendo isomer III does not react to any significant extent under the same conditions. A simple Wagner-Meerwein rearrangement can explain the formation of V from II + HCl, although participation of the (diene)Fe(CO)3 moiety cannot be excluded. When treated with HSO3F/SO2ClF/CD2Cl2, II furnished a stable cationic complex whose1H and13C NMR spectra suggest delocalisation of the homoconjugated positive charge by the (diene)Fe(CO)3 function. Quenching of the cation with methanol yielded theexo-2-methoxy-5,6-dimethylene-syn-7-norbornanol-endo-iron tricarbonyl complex (X) whose structure was established by single crystal X-ray diffraction.

A paramagnetic nuclear magnetic resonance study of the lanthanide complexes[Ln(S2PR2)4]-, R=OMe, OPri. Determination of phosphorus hyperfine coupling and solution structures

Abstract The 1 H and 31 P NMR spectra of the complexes [AsPh 4 ][Ln(S 2 PR 2 ) 4 ] for R = OMe, OPr i have been recorded at room temperature. The proton isotropic shifts are pseudocontact in origin. The total 31 P isotropic shifts have been factored into their contact and pseudocontact contributions. The method used to separate the contact and pseudocontact shifts demonstrates a change in solution structure at Ln = Ho. The change in structure is associated with a reduction in the hyperfine coupling to phosphorus from 1.68 to 0.82 MHz (OMe), and from 1.57 to 0.85 MHz (OPr i . The relative phosphorous pseudocontact shifts falls from 31.7 for the light ions to 3.0 for the heavy ones (OMe), from 16.4 to 0.55 (OPr i CH) and from 57.1 to 1.84 (Opr i CH 3 . These results are consistent with a change in structure of the coordination polyhedron from dodecahedral to square antiprismatic.

Regioselective addition of protic acids to tricarbonyliron complexes of 2,3,5,6-tetrakis(methylene)-7-oxabicyclo[2.2.1]heptane. Crystal structure of (C10H10O)Fe2(CO)6

Abstract The main product of the thermal reaction between the title oxatetraene (I) and Fe2(CO)9 in ether/pentane is the bimetallic complex (C10H10O)Fe2(CO)6-diexo (II), which has C2υ symmetry both in the solid state (X-ray analysis) and in solution. Whereas the protonation of the free ligand leads usually to polymerisation, the addition of a protic acid such as CF3CO2H to II proceeds cleanly at 0°C giving first a (η 3-allyl)Fe(CO)3O2CCF3 complex (III). The intermediate III adds a second equivalent of acid in a slower step (k2/k1 = 0.1, CF3CO2D/CHCl3, 0°C) giving the trans-bis(η3-allyl) isomer IV with high regioselectivity. The addition of CF3CO2D yields the corresponding deuteriomethylallyliron tricarbonyl trifluoroacetates III′ and IV′. No further deuterium incorporation is observed at 0°C, thus confirming the kinetic control of the regioselective double addition of protic acid to II.

Dithiophosphinate complexes of the actinides, III. An NMR study of uranyl dithiophosphinates. Nuclear spin—spin coupling (4JPP) through the uranyl center as evidence for metal—ligand π bonding

Abstract In the complexes [UO 2 (S 2 PR 2 ) 2 ·Cl] − (R = Me, OMe, OEt, OPr i , Ph) and UO 2 {S 2 P(OPr i ) 2 } 2 ·EtOH the nmr spectra of the protons closest to phosphorus exhibit second order features due to appreciable spin—spin coupling between the 31 P nuclei through the metal center. These spectra have been analysed, if necessary with the aid of homonuclear decoupling, to yield values of 4 J PP ranging from 9 to 19 Hz. Additional features are observed in the spectrum for R = OEt as the methylene protons are diastereotopic. A mechanism for the transmission of spin information via π orbitals is proposed.

Crystal and molecular structure of tetraphenylphosphonium tetrakis-(dimethyldithiophosphinato)praseodymium(III)

The title compound crystallises from ethanol in space group Pca21, with cell dimensions a= 19.857(15), b= 11.422(5), c= 19.077(12)A, and Z= 4. The structure was solved by conventional Patterson and Fourier techniques. and refined to R 0.073. The praseodymium is co-ordinated to eight sulphur atoms which have a distorted tetragonal antiprismatic arrangement. Pr–S bond lengths range from 2.888(7) to 3.056(7)(mean 2.976 A). The praseodymium atoms alone form an almost perfect hexagonal lattice.