Maria H. Johansson

Quantifying the trans influence of triphenylarsine. Crystal and molecular structures of cis-[PtCl2(SMe2)(AsPh3)] and cis-[PtCl2(AsPh3)2]·CHCl3

Reaction between a mixture of cis-trans-[PtCl2(SMe2)(2)] and 1 eqiv. AsPh3 in chloroform gives Cis-[PtCl2(SMe2)(AsPh3)] crystallizing in P2(1)/n with a = 10.397(2), b = 14.876(3), c = 13.956(3) Angstrom, beta = 90.86(3)degrees and Z = 4. Selected geometrical parameters are Pt-As 2.3531(10), Pt-S 2.262(2), Pt-Cl (trans to S) 2.301(2), Pt-Cl (trans to As) 2.328(2) Angstrom and S-Pt-As 88.85(6), S-Pt-Cl(2) 90.77(8), As-Pt-Cl(1) 91.07(6) and Cl-Pt-Cl 89.42(7)degrees, cis-[PtCl2(AsPh3)(2)].CHCl3 crystallizes in P2(1)/c with a = 20.557(4), b = 9.5951(19), c = 20.147(4) Angstrom, beta = 96.77(3)degrees and Z = 4. Selected geometrical parameters are Pt-As(1) 2.3599(9), Pt-As(2) 2.3770(9), Pt-Cl(1) (trans to As(1)) 2.3515(18), Pt-Cl(2) (trans to As(2)) 2.3251(18) Angstrom and As-Pt-As 97.87(3), As(1)-Pt-Cl(2) 88.67(5), As(2)-Pt-Cl(1) 84.30(5) and Cl-Pt-Cl 89.32(7)degrees. By comparison with related structures from the literature the following trans influence series was established PMe2Ph > PPh3 > AsPh3 approximate to SbPh3 > Me2SO approximate to SMe2 approximate to SPh2 > NH3 approximate to olefin > Cl- > MeCN

A New Highly Active Diphosphane‐Palladium(II) Complex as a Catalyst Precursor for the Heck Reaction

The new diphosphane ligand cis-1,3-bis[(diphenylphosphanyl)methyl]cyclohexane (4) has been prepared and has allowed the synthesis of the palladium complex cis-[Pd(4)(CO2CF3)2] (6). To obtain cis complexation of the diphosphane in 6 the cyclohexane skeleton adopts a chair conformation with a diaxial orientation of the substituents, a structure that has been verified by an X-ray structure determination. This complex efficiently catalyses the vinylation of iodo- and bromobenzenes in high yields. For the best reaction, with methyl acrylate and iodobenzene, a yield of >98% was obtained with an average turnover frequency of 11 760 h−1 and a turnover number of 1 176 000.

trans-Di­chloro­bis­(tri­phenyl­phosphine-P)­platinum(II)

Two different crystals (A and B) were used to structurally characterize trans-[PtCl2(PPh3)2] and to study random and systematic errors in derived parameters. The compound is isomorphous with trans-[PdCl2(PPh3)2] and with one of the polymorphs of trans-[PtMeCl(PPh3)2] reported previously. Half-normal probability plot analyses based on A and B show realistic s.u.s and negligible systematic errors. R.m.s. calculations give very good agreement between A and B, 0.0088 A. Important geometrical parameters are Pt—P = 2.3163 (11) A, Pt—Cl = 2.2997 (11) A, P—Pt—Cl = 87.88 (4) and 92.12 (4)°. Half-normal probability plots and r.m.s. calculations were also used to compare the title compound with the palladium analogue, showing small systematic differences between the compounds. The torsion angles around the Pt—P bond were found to be very similar to those reported for isomorphous complexes, as well as to the torsion angles around the Pt—As bond in trans-[PtCl2(AsPh3)2]. The NMR coupling constants for the title compound are similar to Pt—P coupling constants reported for analogous trans complexes.

Structures of trans-[PtCl2(PBz3)2], trans-[PtI2(PBz3)2], trans-[Pt(NCS)2(PBz3)2].0.5C6H6 and trans-[PdI2(PBz3)2]

A series of structures of trans-[MX2(PBz3)2] [M = Pt, X = Cl−; PBz3 = tribenzylphosphine (1), I−, trans-diiodobis(tribenzylphosphine)platinum(II) (2), and NCS−, trans-di(thiocyanate)bis(tribenzylphosphine)platinum(II) (3); M = Pd, X = I−, trans-diiodobis(tribenzylphosphine)palladium(II) (4)] have been characterized by X-ray crystallography. In all compounds each tribenzylphosphine has one benzylcarbon close to the coordination plane. In (1), (2) and (4) those (in-plane) C atoms, from the two different PBz3, exhibit an anti conformation along the P—P axis, while (3) has the gauche conformation. Root mean square (RMS) calculations and half-normal probability plots show that the complexes in (2) and (4) are very similar and the only significant differences between them are the M—P bonds, 2.354 (4) and 2.330 (5) A, and the M—I bond distances, 2.604 (1) and 2.611 (2) A, for Pd and Pt, respectively. Calculations of the steric demand of the PBz3 ligands based on the Tolman model gave values ranging from 155 to 178° for the effective and 156 to 179° for the Tolman angles, respectively.

cis-Bis(dimethyl sulfoxide-s)dinitratopalladium(II) and cis-dinitratobis(1,4-oxathiane-S)palladium(II)

The Pd atom in each of the two title compounds, [Pd(NO(3))(2)(C(2)H(6)OS)(2)], (I), and [Pd(NO(3))(2)(C(4)H(8)OS)(2)], (II), coordinates two O atoms from two nitrate ligands and two S atoms from dimethyl sulfoxide (dmso) and thioxane (systematic name: 1,4-oxathiane) ligands in a pseudo-square-planar cis-geometry. In the dmso complex, the distances to palladium are Pd-O 2.067 (2) and 2.072 (2) A, and Pd-S 2.2307 (11) and 2.2530 (8) A. The corresponding distances in the thioxane complex are Pd-O 2.053 (3) and 2.076 (2) A, and Pd-S 2.2595 (9) and 2.2627 (11) A. Both compounds may be regarded as dimers with an inversion centre, where one of the coordinating nitrate O atoms in one molecule also interacts with the Pd atom in the adjacent molecule, with Pd-O distances of 2.849 (9) and 3.31 (3) A in (I) and (II), respectively.

Packing effects on the geometry of neutral platinum(II) complexes due to solvate molecules: the structure of trans‐dichlorobis(triphenylarsine)platinum(II)

A series of structures of trans-dichlorobis(triphenylarsine)platinum(II), recrystallized from four different solvents, have been characterized by X-ray crystallography and were shown to crystallize as different solvates (same metal complex, different crystallization solvents). Their geometric differences induced by packing and solvent molecules were analysed with half-normal probability plots and root-mean-square deviations. The recrystallization solvents used in the investigation were 1,1,1-trichloroethane, dichloromethane, 1,2-dichloroethane and benzene, and the following crystallization modes were obtained. From 1,1,1-trichloroethane the metal complex crystallizes without solvent as trans-[PtCl2(AsPh3)2] in P2(1)/n with Z = 2, a = 9.271 (2), b = 19.726 (4), c = 9.830 (2) A, beta = 111.83 (3)degrees, V = 1668.8 (6) A3, R = 0.0262, and from dichloromethane with two solvent molecules as trans-[PtC12(AsPh3)2].2CH2C12 in Pbca with Z= 4, a = 20.582 (4), b = 8.146 (2), c = 23.491 (5) A, V = 3938.5 (14) A3 and R = 0.0316. From dichloroethane it crystallizes with one solvent molecule as trans-[PtC12(AsPh3)2].C2H4C12 in P1 with Z = 1, a = 9.390 (2), b= 9.548 (2), c = 11.931 (2) A, alpha = 109.70 (3), beta = 108.26 (3), gamma = 98.77 (3) , V= 915.6 (3) A3, R = 0.0390, and from benzene with half a solvent molecule as trans- [PtC12(AsPh3)2].0.5C6H6 in P2(1)/n with Z = 4, a = 11.778 (2), b = 18.712 (4), c = 16.647 (3) A, beta = 104.78 (3) , V= 3547.3 (12) A3 and R = 0.0303. In all four compounds platinum(II) coordinates to triphenylarsine and chloride in a pseudo-square-planar trans configuration. The Pt-As distances are in the range 2.4104 (4)-2.3923 (4) A and the Pt-C distances are in the range 2.309 (2)-2.2839 (9) A. The solvents have a large influence on the packing, resulting in different space groups or different occupancies in the same space group. Half-normal probability plots show that the largest geometric differences, within the metal complex, are in the bond and torsion angles around the As-C bonds. Very similar torsion angles were observed around the Pt-As bond for all the structures, except for one AsPh3 ligand in the benzene solvate, which differs by about 10 from the others. The metal-donor bond distance varies by as much as 0.019 and 0.025 A (95% confidence interval) for Pt-As and Pt-C1, respectively. The variations are essentially caused by intermolecular interactions. Packing efficiency is expressed as the volume filled by each metal complex in the unit cell and is calculated by subtracting the sum of the solvent molecule volumes from the total volume of the unit cell and then dividing by Z. The efficiency is largest in the dichloroethane solvate and smallest in the non-solvated compound, with a difference of approximately 22 A3 per metal complex.

The influence of metal coordination on ligand geometry: the structure of 2-(diphenylphosphino)acetophenone and bis(2-(diphenylphosphino)acetophenone)palladium(II)bistriflate

The structures of 2(diphenylphosphino)acetophenone and bis(2(diphenyl phosphino)acetophenone)palladium(II)bistriflate have been determined by X-ray crystallography. The ligand is of interest because its P,O donor set combines the hard and soft properties. In the Pd-complex, which was prepared by treating tetrakisacetonitrile-palladium-bistriflate with 2-(diphenylphosphino)acetophenone in dichloromethane for 4 h at room temperature, the O-coordination provides a masked coordinative unsaturation. The ligand crystallises in the monoclinic space group P2(1)/c with cell dimensions a = 11.050(2), b = 16.052(3), c = 9.7082(19) Angstrom, beta = 109.58(3)degrees, V = 1622.4(6) Angstrom(3) and Z = 4, synchrotron radiation, lambda = 0.8520 Angstrom. The Pd-complex crystallises in the orthorhombic space group P2(1)2(1)2(1) with cell dimensions a = 11.867(2), b = 18.162(4), c = 19.603(4) Angstrom, V 4224 9(15) Angstrom(3) and Z = 4, MoKalpha radiation. Both structures were solved by direct methods and the refinements resulted in the R-values of 0.059 and 0.043, for the organic compound and the palladium compound, respectively. Two bi-dentate ligand binds to palladium(II) in a cis-configuration. The Pd-O distances are 2.060(3) and 2.096(2) Angstrom and the Pd-P distances 2.2290(10) and 2.2294(10) Angstrom, showing a large trans-influence of the phosphorus atoms. Half-normal probability plot analyses indicate that the s.u.s are largely underestimated in the investigated structures. The bond-angles around the phosphorus atom and the orientation of the keto-substituted phenyl rings as well as the orientation of the keto-groups are highly affected by metal complexation.

Chiral platinum(II) complexes. Crystal and molecular structures of cis-[PtPhCl((R,R)-CHIRAPHOS)] and cis-[PtCl2((R,R)-CHIRAPHOS)]

The reaction between trans-PtPhCl(SMe2)2 and (R,R)-CHIRAPHOS gives cis-[PtPhCl((R,R)-CHIRAPHOS)] (1). The crystals of which are monoclinic, space group P21 with a = 12.875(3), b = 18.012(4), c = 13.864(3) A, β = 109.71(3)° and Z = 4. In CDCl3 1 reacts with Ph2P(C6H4)CH2N(Me)(COEt) to give cis[PtCl2((R,R)-CHIRAPHOS)] (2), the crystals of which are monoclinic, space group P21 with a = 7.8052(16), b = 17.679(4), c = 9.843(2) A, β = 100.67(3)° and Z = 2.

Cis- and trans-influences in [PtCl2(SPh2)2].

Both cis- and trans-dichlorobis(diphenyl sulfide)platinum(II), [PtCl(2)(C(12)H(10)S)(2)], crystallize as mononuclear pseudo-square-planar complexes. In the cis compound, the Pt-Cl distances are 2.295 (2) and 2.319 (2) A, and the Pt-S distances are 2.280 (2) and 2.283 (2) A. In the trans compound, Pt is located on a centre of inversion and the Pt-Cl and Pt-S distances are 2.2786 (15) and 2.3002 (12) A, respectively.

The influence of metal coordination on ligand geometry: the structure of N-t-butyl-2-(diphenylphosphino)benzylammoniumchloride and (N-t-butyl-2-(diphenylphosphino)benzylamine)diacetatepalladium(II)

The structures of N-t-butyl-2-(diphenylphosphino)benzylammoniumchloride and N-t-butyl-2-(diphenylphosphino)benzylaminediacetatepalladium(II) have been determined by X-ray crystallography. The Pd-complex was prepared by treating palladiumdiacetate with N-t-butyl-2-(diphenylphosphino)benzylamine in CH2Cl2 for 4 h at room temperature. The organic compound crystallises in the monoclinic space group P2(1)/c with cell dimensions a = 13.664(3), b = 15.635(3), c = 10.408(2) Angstrom, beta = 100.14(3)degrees, V = 2188.7(8) Angstrom(3) and Z = 4, synchrotron radiation, lambda = 0.9836 Angstrom. The Pd-compound crystallises in the orthorhombic space group Pna2(1) with cell dimensions a = 15.444(3), b = 13.233(3), c = 12.730(3) Angstrom, V = 2601.6(9) Angstrom(3) and Z = 4, Mo Kalpha radiation. Both structures were solved by direct methods and the refinements resulted in the R-values 0.080 and 0.037, respectively. N-t-butyl-2-(diphenylphosphino)benzylammoniumchloride has an extensive hydrogen bonding with two bridging Cl- between the ammonium groups from two different organic ligands. The bi-dentate ligand binds to palladium(II) via both phosphorus and nitrogen, while two acetate bind via one of their oxygens forming a pseudo square-planar coordination around palladium. The Pd-N distance is 2.075(3) Angstrom, Pd-P = 2.2133(9) Angstrom and the Pd-O distances are 2.041(3) Angstrom (trans to N) and 2.092(2) Angstrom (trans to P). Half-normal probability plot analysis indicates that the s.u,.s are underestimated in at least one of the investigated structures. Complexation with palladium influences torsion-angles in the amine side-chain in N-t-butyl-2-(diphenylphosphino)benzylamine as well as bond-angles around the N and P atoms, clearly a consequence of the formation of the chelate, while the crystal packing influences the orientation of the phenyl rings. (Less)