Raija Oilunkaniemi

The oxidative addition of diphenyl diselenide and ditelluride to tetrakis(triphenylphosphine)palladium

Abstract The oxidative addition of diphenyl diselenide to [Pd(PPh3)4] in dichloromethane results in the formation of a dinuclear complex [Pd2(SePh)4(PPh3)2] (1) and a mononuclear complex [PdCl(SePh)(PPh3)2] (2) that have been identified and characterized structurally by X-ray crystallography and 31P-NMR spectroscopy. The analogous reaction involving diphenyl ditelluride leads to a mixture of products. [Pd6Cl2Te4(TePh)2(PPh3)6]·1/2CH2Cl2 (3) can be isolated and its X-ray structure determined. While the oxidative addition of Ph2Se2 mainly involves the clevage of the Se–Se bond, that of Ph2Te2 indicates the rupture of both Te–Te and C–Te. Cumulative evidence shows that the choice of the central atom and the solvent also plays an important role in the oxidative addition. The final polynuclear complexes can be conceived to be formed from the mononuclear addition products by sequential condensation steps.

The NMR spectroscopic and X-ray crystallographic study of the oxidative addition of bis(2-thienyl) diselenide to zerovalent palladium and platinum centers

Abstract The pathway of the reaction of dithienyl diselenide with tetrakis(triphenylphosphine)palladium(0) and -platinum(0) has been explored by the use of NMR spectroscopy and X-ray diffraction. The oxidative addition of dithienyl diselenide to [Pd(PPh 3 ) 4 ] mainly results in the formation of two isomers of dinuclear [Pd 2 (SeTh) 4 (PPh 3 ) 2 ] (Th=2-thienyl, C 4 H 3 S) complex. The workup of the solution produced X-ray-quality crystals of trans -[Pd 2 (SeTh) 4 (PPh 3 ) 2 ]. The corresponding reaction with [Pt(PPh 3 ) 4 ], however, affords isomers of mononuclear [Pt(SeTh) 2 (PPh 3 ) 2 ]. Upon recrystallization from dichloromethane a small amount of crystals of dinuclear [Pt 2 (SeTh) 4 (PPh 3 ) 2 ] is obtained together with those of trans -[Pt(SeTh) 2 (PPh 3 ) 2 ]. While the products from both reactions imply that the oxidative addition takes place with the cleavage of the SeSe bond, a small amount of trans -[PdCl(Th)(PPh 3 ) 2 ] is formed in the reaction of [Pd(PPh 3 ) 4 ] and Th 2 Se 2 in dichloromethane indicating that CSe cleavage may also take place during the oxidative addition.

The X-ray crystallographic study of the reaction of bis(2-thienyl)ditelluride with tetrakis(triphenylphosphine)platinum or -palladium

Abstract The oxidative addition of dithienyl ditelluride to [Pt(PPh3)4] in dichloromethane results in the formation of a trinuclear complex [Pt3Te2(Th)(PPh3)5]Cl (Th=2-thienyl, C4H3S) (1) as well as a mononuclear complex [PtCl(Th)(PPh3)2] that have been identified and structurally characterized by X-ray crystallography and 31P-NMR spectroscopy. The analogous reaction involving [Pd(PPh3)4] forms a mixture of several products. In dichloromethane [Pd6Cl2Te4(TeTh)2(PPh3)6] (2) can be isolated and its X-ray structure determined. In toluene [Pd6Te4(TeTh)4(PPh3)6] (3) is formed. Both 2 and 3 have a similar hexanuclear framework which has previously been reported for [Pd6Te6(PEt3)8] in the literature. These products indicate that the cleavage of both TeTe and CTe bonds as well as the choice of the solvent play an important role in the oxidative addition. The trinuclear and hexanuclear complexes can be considered to be formed from an initial mononuclear addition product. The reaction pathways are compared to those involved in the reaction of Th2Se2 and [M(PPh3)4] (M=Pt, Pd).

Isomerism in bis(phenylselenolato)bis(triphenylphosphine)platinum(II): the crystal and molecular structures of cis- and trans-[Pt(SePh)2(PPh3)2]

Abstract The reaction of cis-[PtCl2(PPh3)2] and NaSePh in benzene produces a mixture of cis- and trans-isomers of the monomeric platinum complex [Pt(SePh)2(PPh3)2]. The low-temperature X-ray structures of both isomers are reported. The structure of cis-[Pt(SePh)2(PPh3)2] is the first crystallographic characterized cis-isomer of mononuclear platinum(II) complex containing only non-chelating organoselenolato and phosphine ligands.

Trends in the structure and bonding of [MCl2{(C4H3S)ECH3}2] (M=Pd, Pt; E=Te, Se)

Abstract The complex formation of (C 4 H 3 E)E′Me (E=S, O; E′=Te, Se) ( 1 – 4 ) with palladium and platinum has been explored by use of NMR spectroscopy and X-ray diffraction. Whereas the 125 Te-NMR spectra of [PdCl 2 {(C 4 H 3 E)TeMe} 2 ] [E=S ( 5 ), E=O ( 6 )] show the existence of both cis - and trans -isomers in solution the spectroscopic information of [MCl 2 {(C 4 H 3 E)SeMe} 2 ] (M=Pd, Pt, E=S, O; 8 – 10 ) indicates the presence of only one isomer. The crystal structure determinations have shown that 5 and 6 are isomorphous and crystallize as cis -isomers forming dimers with close chalcogen–halogen contacts. In contrast, 8 and 10 have turned out to be trans -isomers and form skewed stacks that are bound together in a helical arrangement by weak hydrogen bonds. The structural data indicate that back donation may weakly contribute to the palladium–tellurium bonding in 5 and 6 . In 8 and 10 the effects of the back bonding are negligible.

An experimental and theoretical study of the isomerization of mononuclear bis(arylselenolato)bis(triphenylphosphine)platinum complexes [Pt(SeR)2(PPh3)2]

Mononuclear bis(thienylselenolato)bis(triphenylphosphine)platinum [Pt(SeTh) 2 (PPh 3 ) 2 ] (Th=2-thienyl, C 4 H 3 S) has been prepared by the treatment of cis -[PtCl 2 (PPh 3 ) 2 ] with NaSeTh. The 31 P-NMR spectroscopic information indicates that cis -[Pt(SeTh) 2 (PPh 3 ) 2 ] is initially formed in the reaction. Upon prolonged standing in solution it isomerizes to trans -[Pt(SeTh) 2 (PPh 3 ) 2 ] . The reaction of cis -[PtCl 2 (PPh 3 ) 2 ] with LiSeFu (Fu=2-furyl, C 4 H 3 O) affords immediately a mixture of cis - and trans -isomers of [Pt(SeFu) 2 (PPh 3 ) 2 ] with the relative amount of the trans -isomer increasing with time. The recrystallization of the two reaction mixtures yielded cis , anti - and trans , syn -isomers of [Pt(SeTh) 2 (PPh 3 ) 2 ] as well as cis,syn - and trans , anti -isomers of [Pt(SeFu) 2 (PPh 3 ) 2 ]. Their structures were compared with those of cis , anti - and trans , anti -isomers of [Pt(SePh) 2 (PPh 3 ) 2 ]. The geometries and relative stabilities of all isomers of [Pt(SeTh) 2 (PH 3 ) 2 ], [Pt(SeFu) 2 (PH 3 ) 2 ] and [Pt(SePh) 2 (PH 3 ) 2 ] were studied by the use of ab initio molecular orbital techniques in order to model the structures and isomerization of the observed mononuclear selenolato complexes.

Halogenation of tellurium by SO2Cl2. Formation and crystal structures of (H3O)[Te3Cl13]·1/2SO2, [(C4H8O)2H][TeCl5]·(C4H8O), [(Me2SO)2H]2[TeCl6], and [Ni(NCCH3)6][Te2Cl10]

Abstract The halogenation of elemental tellurium with SO2Cl2 in various solvents has been investigated. (H3O)[Te3Cl13]·1/2SO2 (1) and [(C4H8O)2H][TeCl5]·(C4H8O) (2) were obtained in CS2 and THF, respectively. When DMSO is added into the THF solution of tellurium and SO2Cl2, [(Me2SO)2H]2[TeCl6] (3) is formed. In the acetonitrile solution tellurium and SO2Cl2 form [Ni(NCCH3)6][Te2Cl10] (4) in the presence of metallic nickel. All compounds 1–4 were characterized by 125Te NMR and by X-ray crystallography. The formation of the anions has been discussed.

Cation-anion interactions in triphenyl telluronium salts. The crystal structures of (Ph3Te)2[MCl6] (M = Pt, Ir), (Ph3Te)[AuCl4], and (Ph3Te)(NO3).HNO3

Abstract Triphenyltelluronium hexachloroplatinate ( 1 ), hexachloroiridate ( 2 ), tetrachloroaurate ( 3 ), and tetrachloroplatinate ( 4 ) were prepared from Ph 3 TeCl and potassium salts of the corresponding anions. Upon recrystallization of 4 from concentrated nitric acid, K 2 [PtCl 6 ] and (Ph 3 Te)(NO 3 )·HNO 3 ( 5 ) were obtained. The crystal structures of 1 – 3 and 5 are reported. Compounds 1 and 2 are isostructural. They are triclinic, P 1, Z =2 (the asymmetric unit contains two formula units). Compound 1 : a =10.7535(2), b =17.2060(1), c =21.4700(3) A, α =78.9731(7), β =77.8650(4), γ =78.8369(4)°. Compound 2 : a =10.7484(2), b =17.1955(2), c =21.4744(2) A, α =78.834(1), β =77.649(1), γ =78.781(1)°. Compound 3 is monoclinic, P 2 1 / c , Z =4, a =8.432(2), b =14.037(3), c =17.306(3) A, β =93.70(3)°. Compound 5 is monoclinic. P 2 1 / n , Z =4, a =9.572(2), b =14.050(3), c =13.556(3) A, β =90.76(3)°. The primary bonding in the Ph 3 Te + cation in each salt is a trigonal AX 3 E pyramid with TeC bond lengths in the range 2.095(8)–2.14(2) A and the bond angles 94.1(6)–100.9(5)°. The weak Te⋯Cl ( 1 – 3 ) and Te⋯O ( 5 ) secondary interactions expand the coordination sphere. In 1 and 2 the cation shows a trigonal bipyramidal AX 3 YE coordination with one primary TeC bond and the shortest secondary Te⋯Cl contact in axial positions and the two other TeC bonds and the lone-pair in equatorial positions. The cation in 3 shows a distorted octahedral AX 3 Y 3 E environment and that in 5 is a more complex AX 3 Y 3 Y′ 2 arrangement. In both latter salts the structure is a complicated three-dimensional network of cations and anions.

C4H3SSeCH2CH2OC6H5: synthesis, characterization and reaction with palladium(II) and nickel(II)

Abstract ThSeCH2CH2OPh (Th=2-thienyl, C4H3S-; Ph=phenyl) (2) has been prepared by the reaction of BrCH2CH2OPh (1) and ThSeLi. The compound was characterized by 13C{1H}- and 77Se-NMR spectroscopy and X-ray crystallography. 2 is monoclinic, space group P21/c, a=10.865(2), b=5.152(1), c=41.996(8) A, β=92.20(3)°. All bond lengths and angles are quite normal as exemplified by the respective SeC(alkyl) and SeC(aryl) bonds of 1.957(6)–1.966(6) and 1.901(7)–1.905(7) A. The lattice is composed of discrete molecules that are joined together by weak hydrogen bonds into a three-dimensional network. Upon treating ThSeCH2CH2OPh with [PdCl2(NCPh)2] and [NiCl2(PPh3)2] in benzene, a dinuclear palladium complex [Pd2Cl2(μ-Cl)(μ-SeTh)(PPh3)2] (3) and a mononuclear complex [PdCl2(PPh3)2] (4) were formed together with a precipitation of NiCl2. The X-ray quality crystals were recrystallized in CH2Cl2. 3·2.5CH2Cl2 is monoclinic, space group C2/c, a=32.907(7), b=14.545(3), c=22.433(5) A, β=114.37(3)° and contains a novel asymmetrical arrangement of one bridging chlorido and thienylselenolato ligand. Both palladium atoms show an square-planar coordination. The terminal PdCl bond lengths are 2.388(1) and 2.346(1) A with slightly longer distances of 2.418(1) and 2.450(1) A involving the bridging chlorido ligand. The PdSe distances are 2.4092(9) and 2.4376(7) A.

Synthesis and structural characterization of [RuCl2(CO)2(TePh2)2]·1/2C6H6

Abstract The reaction of Ph2Te with [RuCl2(CO)3]2 affords a monomeric ruthenium complex [RuCl2(CO)2(TePh2)2]. The X-ray structure shows the formation of the trans(Ph2Te), cis(Cl), cis(CO) isomer. The 13C NMR and 125Te NMR spectra of the complex are reported.