Anca Silvestru

Triphenyltelluronium derivatives of dithiophosphorus ligands: Crystal and molecular structure of [Ph3Te][S2PPh2] and [Ph3Te][(SPPh2)2N], displaying weak cation-anion Te…S secondary interactions

Abstract Triphenyltelluronium diphenylphosphinodithioate, [Ph 3 Te][S 2 PPh 2 ] ( 1 ) and tetraphenyldithioimidodiphosphinate, [Ph 3 Te][(SPPh 2 ) 2 N] ( 2 ), were obtained by metathesis reaction between Ph 3 TeCl and NH 4 [S 2 PPh 2 ] and K[(SPPh 2 ) 2 N], respectively, and were characterized by IR, MS and multinuclear NMR. The molecular structure of both compounds was investigated by X-ray diffractometry. The compounds are monomeric and predominantly ionic in the solid state. The Te…S interactomic distances (3.331 and 3.655 A in 1 , and 3.264 and 3.451 A in 2 indicate weak cation-anion secondary interactions. In both compounds the tellurium atom is five-coordinated, with distorted square-pyramidal geometry. The coordination polyhedron in 2 is less distorted due to the flexibility of the SPNPS system and the larger S…S bite of this ligand (4.276 A in 2 , vs 3.368 A in 1 ).

Gold and silver complexes with the diselenium ligand [Ph2P(Se)NP(Se)Ph2]-

Abstract The treatment of potassium diselenoimidodiphosphinato with silver(I) or gold(III) derivatives leads to the synthesis of three-coordinated, [Ag{(SePPh2)2N}(PPh3)], tetranuclear, [Ag4{(SePPh2)2N}3]OTf (4) (OTf=OSO2CF3), or square-planar, [Au(C6F5)2{(SePPh2)2N}] (5), complexes. The crystal structures of [Au2{(SePPh2)2N}(PPh3)2]OTf (2), 4 and 5 have been established by X-ray diffraction. Complex 2 is associated by gold–gold interactions forming tetranuclear dimers. In complex 4 four silver atoms forming a distorted tetrahedron are bridged by three ligands, and 5 shows the expected square-planar coordination at gold.

First nickel(II) complexes containing tetrahedral NiO2S2 cores. The molecular structures of Ni[(OPPh2)(SPR2)N]2 (R=Ph, Me)

Abstract Ni[(OPR′2)(SPR2)N]2 complexes were obtained in good yields by reacting NiCl2·6H2O and the alkaline salts of the corresponding tetraorganomonothioimidodiphosphinic acids. All compounds were characterized by elemental analysis and IR. The molecular structure of Ni[(OPPh2)(SPR2)N]2 (R=Ph, Me) has been determined by single-crystal X-ray diffractometry. Ni[(OPPh2)-(SPPh2)N]2 (1) crystallizes in the monoclinic space group P21/c (no. 14), and Ni[(OPPh2)(SPMe2)N]2 (2) crystallizes in the triclinic space group P1 (no. 2). The crystals of both compounds contain discrete mononuclear molecules. The asymmetric ligands act as monometallic biconnective units which results in a tetrahedral NiO2S2 core.

Triphenyltellurium(IV) dichalcogenoimidodiphosphinates containing novel six-membered TeXYP2N chelate rings. X-ray structure of Ph3Te[SPPh2) (OPPh2)N] and Ph3Te[(OPPh2)2N]

Abstract Several compounds of the type Ph3Te[(XPR2(YPR′2)N] (R=Me, Ph; R′=Me, Ph; Y=O,S) were obtained by metathesis reactions between Ph3TeCl and M[XPR2)(YPR′2)N]. Two of these (tetraphenylmonothioimidodiphosphinato)triphenyltellurium(IV), Ph3Te[(SPPh2)(OPPh2)N] (1) and (tetraphenylimidodiphosphinate)triphenyltellurium(IV), Ph3Te[(OPPh2)2N] (2) were obtained by metathesis reactions between Ph3TeCl and K[(CPPh2(OPPh2)N] or K[(OPPh2)2H], respectively. The compounds were characterized by IR and multinuclear (1H, 13C and 31P) NMR. The molecular structure of both compounds has been determined by X-ray diffractometry. Ph3Te[(SPPh2)(OPPh2)N] crystallizes in the monoclinic P2 1 c space group (No. 14) and has the cell parameters a=13.64(1), b=13.88(1), c=20.268(7) A , β=105.37(5)°, V=3699(4) A 3 and Z=4 , and Ph3Te[(OPPh2)2N] crystallizes in the monoclinic C2 c space group (No. 15) and has the cell parameters 1=20.748(6), b=12.824(5), c=28.093(6) A , β=115.48(2)°, V=7274(3) A 3 and Z=8 . Both compounds are monomeric and the immediate environment about tellurium can be described as octahedral with the apparently steochemically active lone pair occupying the axial position trans to a phenyl group from Ph3Te. The other two phenyl groups and the two long tellurium-chalcogen secondary interactuions [Te…O 2.77(1) and Te…S 3.282(4) in (1) and Te…O(1) 2.926(6) and Te…O(2) 2.654(6) A in (2) respectively] complete the equatorial plane around tellurium. As a result novel six-membered TeOSP2N and TeO2P2N inorganic chelate rings are formed. Five other compounds, Ph3Te[(SPPh2)(OPMe2)N], Ph3Te[(SPMe2)(OPPh2N], Ph3Te[(OPMe2)(OPPh2)N], Ph3Te[(SPMe2)2N] and Ph3Te[(SPMe2)(SPPh2N], were identified unequivocally but unfortunately attempts to isolate them failed due to decomposition. The reaction mixtures were investigated by multinuclear (1H, 11C and 31P) NMR spectroscopy.

New aryltellurium(II) diorganophosphinodithioates. Crystal structure of red (294 K) and yellow (173 K) ∞1[PhTeS (S)PPh2], a supramolecular polymer displaying an unusual coordination pattern of the phosphinodithioato ligand

Abstract Aryltellurium(II) diorganophosphinodithioates, ArTeS2PR2, were prepared by treating Ar2Te2 with R2 P(S)SSP(S)R2 (Ar = Ph, p-tolyl; R = Me, Et, Ph) (method (a)) or PhTeCl3 with NaS 2PR2 · 2H2O (R = Me, Et) (method (b)). The compounds were characterized by IR, 1H and 31P NMR, and mass spectroscopy. The compound PhTeS(S)PPh2 displays thermochromism; a yellow form is observed below −60°C and a red form at room temperature. The crystal structure of PhTeS(S)PPh2 was investigated using X-ray diffraction, at both low and room temperature. In both cases the molecules are associated in polymeric chains through unusual monodentate biconnective phosphinodithioato bridges, in which the sulfur atom single bonded to phosphorus of the molecule units is involved in secondary bonding to the tellurium atoms of a symmetry related molecule (TeS(P) 2.406 A, Te … S(P) 3.383 A at 173 K and, respectively, TeS(P) 2.401 A, Te … S(P) 3.422 A at 294 K). The sulfur atoms doubly bonded to phosphorus are not involved in coordination to tellurium (non-bonding Te … S(P) 3.989 A at 173 K, and 3.964 A at 294 K, respectively).

Metal-oxygen versus metal-sulfur bonding of the ambident monothiophosphinato ligand in some triphenylmeta(IV) derivatives, Ph3M[OSPR2] (M = Ge, Sn, Pb). Crystal structures of Ph3Ge[O(S)PPh2] and [Ph2Sn{O(S)PPh2} (μ-OH)]2

Abstract Diorganomonothiophosphinato-triphenylmetal(IV) derivatives, Ph 3 M(OSPR @ ) (M = Ge, Sn, Pb; R = Me, Et, Ph), were prepared and investigated. The IR and multinuclear ( 1 H, 13 C, 31 P) NMR spectra are discussed in relation to the MO and/or MS bonding of the ambident OSPR 2 − ligand. The crystal and molecular structures of Ph 3 Ge[O(S)PPh 2 ] ( 1 ) and [Ph 2 Sn{O(S)PPh 2 } (μ-OH)] 2 ( 2 ) were determined by X-ray diffractometry. The asymmetric unit for Ph 3 Ge[O(S)PPh 2 ] contains two independent molecules. The monothiophosphinato group is bonded to germanium only through oxygen (av. GeO 1.826, Ge···S 3.892 A), leading to a tetrahedral coordination around the germanium atom. The crystal of [Ph 2 Sn{O(S)PPh 2 } (μ-OH)] 2 consists of dimeric units built up through SnOSn bridges involving the oxygen atom of the hydroxy groups. The monothiophosphinato group is again monodentate [Sn(1)O(1) 2.089(3), Sn(1)···S(1) (non-bonding) 4.164 A] and the coordination geometry around tin is trigonal bipyramidal, with the O(1) atom of the phosphorus ligand and the O(2′) atome of a bridging hydroxy group in axial positions.

Solution and solid state structural investigations of organotin(IV) compounds containing asymmetric imidodiphosphinato ligands. X-ray structures of R′′2Sn[(OPMe2)(OPPh2)N]2 (R=Me, Bun, Ph)

Abstract Organotin(IV) derivatives of the type R2Sn[(OPMe2)(OPPh2)N]2 (R=Me, Bun, Bz, Ph) were prepared by metathesis reactions between R2SnCl2 and the potassium salt of the imidodiphosphinic acid, in toluene. Me3SnCl and K[(OPMe2)(OPPh2)N] (1:1 molar ratio) in chloroform at room temperature gives Me3Sn[(OPMe2)(OPPh2)N], while the NMR studies indicate that the corresponding triphenyltin(IV) derivative disproportionates gradually in solution to give Ph2Sn[(OPMe2)(OPPh2)N]2. Attempts to grow crystals of the trimethyltin(IV) derivative also gives Me2Sn[(OPMe2)(OPPh2)N]2 as a redistribution product. The compounds were characterized by IR and multinuclear NMR spectroscopy. The crystal and molecular structures of R2Sn[(OPMe2)(OPPh2)N]2 [R=Me (1), Bun (2), Ph (4)] were established by X-ray diffractometry. The compounds exhibit similar spiro-bicyclic structures, with the tin atom as spiro atom and chelating ligands with the oxygen atoms of the similar OPR2 groups in trans positions. The coordination geometry around the central metal atom is octahedral, with CSnC and OSnO (trans) angles of 180°. No significant differences were noted in the length of the tinoxygen, phosphorusoxygen and phosphorusnitrogen bonds, respectively, in relation to the different organic groups attached to tin or phosphorus atoms in a ligand moiety. The solution and solid state structures of the title compounds are discussed comparatively.

Synthesis of (Me3SiCH2Sb)n and reactions with ditellurides: crystal structure of [Cp2Co][Me3SiCH2SbCl3]

Abstract Substitution of phenyl groups in Ph2SbR (1) (R=Me3SiCH2) with chlorine atoms leads to RSbCl2 (2). Reduction of 2 with magnesium in tetrahydrofuran gives red crystals of (RSb)n (3) and a black solid containing the polymer (RSb)x. Solutions of 3 in C6D6 are yellow. They consist of an equilibrium mixture of (RSb)5 and (RSb)4. The reaction between 2 and cobaltocene in tetrahydrofuran or C6D6 leads to the polymer (RSb)x and to the salt [COCp2]+[RSbCl3]− (4). The structure of 4 has been determined by single-crystal X-ray diffraction. It contains a centrosymmetric double-chlorine-bridged dimeric anion. The ditellurostibane RSb(Te-p-Tol)2 (5) has been obtained with a quantitative yield through a complete reaction between 3 and (p-TolTe)22. Compound 5 has been detected in the product mixtures resulting from reactions of polymeric (RSb)x with (p-TolTe)2 or by reducing p-TolTeCl3 and RSbCl2 with magnesium in tetrahydrofuran.

Diphenyltellurium(IV) bis(diorganophosphinodithioates). X-ray crystal structure of Ph2Te(S2PPh2)2·0.5CHCl3 and a multinuclear NMR study of the decomposition process of Ph2Te(S2PR2)2 to Ph2TeII and [R2P(S)S]2

Abstract New diorganophosphinodithioato derivatives, Ph 2 Te(S 2 PR 2 ) 2 , were formed in the reaction of Ph 2 TeCl 2 with R 2 PS 2 M· x H 2 O (R = Me, Et, M = Na, x = 2; R = Ph, M = NH 4 , x = 0) in a 1:2 molar ratio. In the case of alkyl derivatices, the expected Te IV compounds decomposed rapidly to Ph 2 Te II and the corresponding disulphane, R 2 P(S)-S-S-(S)PR 2 , as proved by multinuclear ( 1 H, 13 C, 31 P) NMR studies. By contrast, for R = Ph the desired tellurium compound could be isolated as a pure sample and its crystal and molecular structure has been determined by single-crystal X-ray diffractometry. The 1,1-dithio ligands are coordinated to tellurium as anisobidentate groups, with single PS [2.081(2), 2.057(2) A] and a double PS [1.954(2), 1.966(2) A] bonds coupled with primary TeS [2.597(2), 2.658(2) A] bonds and intramolecular Te…S (3.316, 3.286 A) secondary interactions, respectively. If only the primary covalent bonds are considered the coordination geometry about the central tellurium atom can be described as ψ-trigonal bipyramidal, with two sulphur atoms in axial positions [S(1)Te(1)S(3) 174.1(1)°]. Two carbon atoms and the stereochemical active lone electron pair of tellurium occupy the equatorial sites. If the secondary interactions of tellurium with the S(2) and S(4) atoms which are placed above and below the C 2 Te equatorial plane are taken into account the coordination number at tellurium is increased to 7 (including the lone pair).

Synthesis and crystal structures of two trigonal bipyramidal Sb(V) compounds, R2SbBr3 and R3Sb(S2PPh2)2 (R=Me3SiCH2)

Abstract Addition of Br 2 to R 2 SbBr (R=Me 3 SiCH 2 ) gives R 2 SbBr 3 ( 1 ). R 3 SbBr 2 reacts with NH 4 S 2 PPh 2 to form R 3 Sb(S 2 PPh 2 ) 2 ( 2 ). The structures of 1 and 2 have been determined by single-crystal X-ray diffraction.