Volume 47, Issue 5

A new route for the preparation of (Me 3 Ge) 3 N (2 a) using Me 3 GeCl and (Me 3 Sn) 3 N is described. Cp′TiCl 3 (Cp′ = Me 5 C 5 (la) and Me 3 SiC 5 H 4 (lb)) reacts with (Me 3 Sn) 3 N to yield (Cp′TiClNSnMe 3 ) 2 (3a) and (3b). (Me 5 C 5 TiFNSnMe 3 ) 2 (3c) is formed when Me 5 C 5 TiF 3 is treated with (Me 3 Sn) 3 N. The X-ray structures of 3a and (Me 3 SiC 5 H 4 TiClNtBu) 2 (5) are reported. 3a and 5 consist in the solid state of four-membered Ti 2 N 2 rings with the substituents in different positions.

In the enantioselective hydrosilylation of acetophenone with diphenylsilane, a polystyrenebound heterogeneous Rh/pyridineoxazoline catalyst achieved higher optical inductions than a comparable homogeneous catalyst. After using the polymeric catalyst 8—10 times, the catalytic activity decreased markedly and an inversion of the product configuration was observed, the enantiomeric excess rising to 92% ee. These results indicate that the polymeric catalyst contains several catalytically active species with different enantioselectivity and stability.

Maleic anhydride (MA) was polymerized by a free radical mechanism (PMA) and transformed into the poly-acid and its alkali salts, the ionic conductivities of which were determined. Blends of the lithium salt with propylene carbonate (PC), low molecular weight poly(ethyleneglycol) (PEG), and some crown ethers show improved conductivities. Alkali alcoholates and alcohols react with PMA to form linear poly(methylesters), comb-shaped polymers with methoxy poly(ethyleneoxide) pendants, and PEG cross-linked structures. Alkalisalt/ester copolymers as well as LiClO 4 podand complexes were studied. Among these, the viscous comb-shaped polymers show the highest conductivities, when having a Li : O ratio of 1:2.7, i.e. x = 10 -5 S/cm at 20°C and 4 · 10 -3 S/cm at 80°C.

The adsorption of several cobalt(III) complex ions with carbonato or two aqua ligands in cis-position (and related complexes) was studied with the objective of a comparison with the adsorption of UO 2 2+ ions from [UO 2 (CO 3 ) 3 ] 4- solutions. One CO 3 2- group per adsorbed UO 2 2+ ion was found on the TiO 2 surface after vacuum-drying at room temperature. Pre-adsorption of HPO 4 2- ions resulted in an increased UO 2 2+ uptake, whilst coverage of the TiO 2 surface with adsorbed Al hydroxo complexes resulted in the opposite effect. The adsorption rate as well as the saturation uptake were higher for the cis-[Co(NH 3 )4(H 2 O)2] 3+ complex than for [Co(NH 3 )4(CO 3 )] + . The diffuse reflectance spectra are similar for both adsorbates. Also with cis-[Co(trien)(H 2 O)2] 3+ and [Co(trien)(CO 3 )] + the diaqua is more rapidly adsorbed, whereas the saturation values are very similar. No carbonate is found in the adsorbates with both carbonato complexes, the ammine or trien ligands are retained on the adsorbed Co III ions, however. Temperature-programmed decomposition spectra showed that the bonding of the ammine ligands is weakened in the adsorbed complexes compared to bulk salts of the complex ions. It is concluded that the metal complexes are anchored to the TiO 2 surface by bonding to two surface oxygen ions.

Alkenyl substituted 1H-1,2-azaborolyl (Ab) complexes are promising candidates for stereoselective reactions, due to the chirality of the AbM moiety and the intramolecular coordination of the alkenyl group to the metal atom. The synthesis of [1-tert-butyl-2-methy1-3-(4-penten- l -y1)-η 5 -1H-1,2-azaborolyl]-bis(triphenylphosphine)rhodium (3) is achieved by the reaction of AbLi (2) [from AbH (1)] with (Ph 3 P) 3 RhCl. In benzene solution one PPh 3 ligand of 3 is substituted by the C=C group of the pentenyl substituent. Simultaneously the η 5 -coordination of the Ab ring changes to an allylic η 3 -coordination forming 4. Steric reasons seem to be responsible for this intramolecular rearrangement. The shorter 2-propen-1-yl substituent is unable to act in the same way and therefore only forms the stable complex [1-tert-butyl-2-methyl-3-(2-propen- l -yl)-η 5 -1H-1,2-azaborolyl]-bis(triphenylphosphine)rhodium (7). Mass spectrometry, 1 H, 11 B and 31 P NMR data were used to characterize the novel complexes.

Tetrakis(diphenylphosphanylmethyl)methane C(CH 2 –PPh 2 ) 4 was prepared (following modified literature methods), its structure determined by X-ray diffraction methods, and its spectroscopic data complemented. The tetranuclear gold(I) complex C[CH 2 –PPh 2 ·AuCl] 4 was obtained by treatment of the tetrafunctional ligand with four equivalents of (Me 2 S)AuCl, and its structure was also determined. The changes in structure and conformation as compared to that of the free ligand provide evidence for attractive intramolecular Au ··· Au interactions for one pair of gold(I) centers. Owing to steric congestion of the molecule, the remainder pair are independent structural units not engaged in metal–metal interactions.

Ni(II) salts and the tetradentate thioether-thiolate ligand ′S 4 -C 2 ′ 2- (= 1,2-bis(2-mercaptophenylthio)ethane(2-)) yield [Ni(′S 4 -C 2 ′)] x (1), that also forms when Na 2 [Ni(′S 2 ′ ) 2 ] (′S 2 2- ′ = o-benzenedithiolate(2-)) is alkylated by 1,2-dibromoethane. In boiling pyridine 1 adds two solvent molecules and gives pseudooctahedral [Ni(pyr) 2 (′S 4 -C 2 ′ )] (2) which was characterized by X-ray structure determination. Reaction of 1 with PMe 3 yields [Ni(PMe 3 )(′S 4 -C 2 ′)] (4). X-ray structure determination of 4 showed that the Ni center is surrounded by one P and four S atoms in a distorted tetragonal pyramid in which the P atom, one thioether S atom and both of the thiolate S atoms form the base while the second thioether S atom occupies the apical position. Reaction of 1 with n-BuLi leads to removal of the C 2 H 4 bridge of the ′S 4 -C 2 ′ 2- ligand and formation of Li 2 [Ni(′S 2 ′) 2 ]. When [Ni(acac) 2 ] 3 is reacted with ′ bu S 4 -C 2 ′ 2 (= 1,2-bis(3,5-ditertiarybutyl-2-mercaptophenylthio)ethane(2-)) which is analogous to ′S 4 -C 2 ′ 2- , the trinuclear [Ni(′ bu S 4 -C 2 ′)] 3 (3) forms. 3 · THF was characterized by X-ray structure determination. It contains one tetrahedrally distorted and two planar [NiS 4 ] cores that are connected via the C 2 H 4 groups of the ligands such that a macrocycle forms. PMe 3 cleaves 3 to give mononuclear [Ni(PMe 3 )(′ bu S 4 -C 2 ′)] (5). Due to its lability, it was characterized only by spectroscopic methods.

The reaction of [W(CPh)Br(CO) 2 (py)2] (1) with one equivalent of triisopropylphosphine gives [W(CPh)Br(CO) 2 (py)(P-i-Pr 3 )] (3). The reaction of 1 with two equivalents of triisopropylphosphine under irradiation with visible light affords trans-[W(CPh)Br(CO) 2 (P-i-Pr 3 )2] (4). Substitution of the pyridine ligand in 3 by other ligands L (t-butylisocyanide, trimethylphosphine and trimethylphosphite) gives the complexes [W(CPh)Br(CO) 2 (L)(P-i-Pr 3 )]. Reaction of 4 with t-butylisocyanide gives trans-[W(CPh)Br(CO)(CNCMe 3 )(P-i-Pr 3 ) 2 ]. Irradiation of [W(CPh)Br(CO) 2 (tmeda)] in the presence of excess trimethylphosphine gives [W(CPh)Br(CO)(PMe 3 ) 3 ]. The reaction of 1 with maleic anhydride gives [W(CPh)Br(CO)(C 4 H 2 0 3 )(py) 2 ].

Cyclic and non-cyclic bis(amino)phosphenium cations (1 to 4) together with their precursors (bis(amino)phosphorus chlorides 5 to 8) and some other bis(amino)phosphorus compounds (9 to 14) have been studied by 13 C, 15 N (natural abundance), 29 Si and 31 P NMR spectroscopy. 15 N chemical shifts and coupling constants 1 J( 31 P 15 N) of phosphenium cations have been determined for the first time. NMR data of 1 to 4 are compared with those of a bis(amino)carbene and various bis(amino)stannylenes. In the phosphenium cations 1 to 4 the 15 N nuclear shielding is considerably reduced (ca. 70 to 100 ppm as compared with 5 to 14) and there is a crude linear relationship between δ 15 N and δ 31 P values. Changes in the δ 15 N values of 1 to 4 do not reflect P-N (pp)π interactions. A positive sign has been determined for the coupling constants 1 J( 31 Ρ 15 Ν) [reduced coupling constants 1 K( 31 P 15 N) < O] for the phosphenium cations and for all other P(III)-N compounds studied. This was achieved by applying various one- and twodimensional heteronuclear double resonance techniques. The experiments also gave signs of the coupling constants 2 J( 31 PN 13 C), 2 J( 31 PN 29 Si), 3 J( 31 PNC 13 C), 3 J( 31 PNSi 13 C), 4 J( 31 PNCC 1 H) and 4 J( 31 PNSiC 1 H). Negative contributions to 1 K( 31 P 15 N), arising from the lone pair of electrons at phosphorus, are more noticeable in the case of the phosphenium cations.

The reaction of [(CO) 3 Mn(dppm) 2 Rh(CO)] (1) with H 2 S in dichloromethane yields [(CO) 3 Mn(dppm) 2 (μ-S)Rh(CO)] (2), which is characterized by IR, 31 P{ 1 H}, 1 H, 13 C{ 1 H} nmr and mass spectra. The crystal structure of 2 was determined by X-ray diffraction: space group P2 1 /n, Z = 4, a = 1232.6(3), b = 2558.8(4), c = 1640.8(2) pm, β = 97.74(2)°, R/R w = 0.048/0.057. The dimeric complex shows A-frame structure possessing a bridging sulfur and a semibridging CO group. 2 cannot be oxidized to the corresponding SO 2 bridged complex [(CO) 3 Mn(dppm) 2 (μ-SO 2 )Rh(CO)] (3). The reaction of 2 with SO 2 , however, yields the SO 2 bridged complex [(CO) 2 Mn(dppm) 2 (μ-S)(μ-SO 2 )Rh(CO)] (5); in dichloromethane 2 is readily chlorinated to afford the salt [(CO) 3 Mn(dppm),(μ-S)RhCl]Cl (4).

Benzo-1,3,2-diselenazolylium chloride can be prepared analogously to the corresponding sulfur compound. The cation has been characterized as its perchlorate by X-ray structure analysis. Reduction via the unstable neutral radical state finally affords the nitrogen-free ‘dibenzotetraselenocine’.

In the effort to react W(CO) 6 with (PPh 4 ) 2 [As 2 Cl 8 ] and Cr(CO) 6 with PPh 4 [As 2 SBr 5 ] in tetrahydrofurane under UV irradiation the title compounds were obtained as main products. Their crystal structures were determined by X-ray diffraction. PPh 4 [AsCl 4 (THF)2], monoclinic, P2/c, Z = 2, a = 881.6(3), b = 809.0(6), c = 2418.6(9) pm, β = 99.44(4)°, R = 0.086 for 1619 observed unique reflexions. PPh 4 [AsBr 4 (THF) 2 ], monoclinic, C 2/c, Z = 4, a = 2459.2(5), b = 748.2(3), c = 1784.3(4) pm, β = 94.02(2)°, R = 0.080 for 1513 reflexions. In both compounds ions [AsX 4 (THF)2] - are located on inversion centers; they have octahedral coordination with trans configuration; the stereochemical activity of the lone electron pairs does not show up in deviations of the bond angles, but in increased bond lengths. The PPh 4 + ions are stacked to columns in the b direction.

The monoclinic weberites Na 2 CoFeF 7 (a = 1262.2(10), b = 736.0(4), c = 2451.6(20) pm, β = 99.71(5)°) and a second modification of Na 2 CuFeF 7 (a = 1244.4(2), b = 734.3(1), c = 2467.2(5) pm, β = 99.27(3)°), crystallize isotypically in space group C 2/c, Ζ = 16. The structure is an intermediate type between orthorhombic and trigonal weberites, characterized by pairs ofparallel chains of octahedra [MF 4 F 2/2 ] 3 - (M = Co, Cu) which run in turn along [110] and [110]. The average distances are Fe-F = 192 pm in the [FeF 63 - octahedra of both compounds. Considerable splitting of distances occurs in the [CoF 6 - octahedra (av. Co-F = 201 pm), and by Jahn-Teller distortion even more in those of [CuFJ 4 - (av. Cu-F = 199 pm). One of the copper surroundings is (pseudo)tetragonally elongated (av. 209/194 pm), the other exhibits an unusual splitting into three long and three short bonds (av. 204/193 pm) in meridional positions. Some structural relations are discussed.

The new ether-phosphine ligand (oxetanyl-2-methyl)diphenylphosphine (1) with strongly basic properties is obtained by reaction of LiPPh 2 with 2-chloromethyloxetane. Reaction of 1 with Cl 2 Ru(PPh 3 ) 3 results in the formation of the bis(chelate) complex trans-Cl 2 Ru(P~O) 2 (2). (P∼O = η 1 -P-coordinated; P~O = η/ 2 -O,P-coordinated). With CO only one Ru-O bond is cleaved to give the monocarbonylruthenium(II) complex trans-Cl 2 Ru(CO)(P∼O)(P~O) (3). 3 shows fluxional behaviour only at higher temperatures as demonstrated by 31 P{ 1 H} NMR spectra.

2,5-Bisdimethylamino-2,5-dihydrobenzo[b]-1,2,5-thiadiborole (2) has been obtained from the diiodine-derivative by reaction with dimethyl-aminotrimethylsilane. Reaction of 2 or 2,5-bisdimethylamino-1′,2′-dimethyl-2,5-dihydrobenzo[b]-thiadiborole with di-tert-butyl-, tertbutyl-trimethylsilyl- and bistrimethylsilyl-sulfurdiimide yields the 2,7,3,6-tetrahydrobenzo[b]-1,2,7,3,6-thiadiazadiborepines (3a-3e). 1 H, 11 B, 13 C NMR, MS and analytical data and results of analysis are given. For 3a the X-ray structure is reported.

(NEt 4 ) 2 S 5 was prepared from NEt 4 Cl and Na 2 S 4 in ethanol. Its reaction with boiling acetonitrile yielded tetraethylammonium tetrathiooxalate. (NEt 4 ) 2 [C 2 S4] was also obtained by heating (NEt 4 ) 2 S 5 with tetraethylammonium dithioacetate in ethanol. Benzyltriethylammonium tetrathiooxalate, (NEt 3 Bz) 2 [C 2 S 4 ]· 2 toluene, crystallized after NEt 3 BzCl and Na 2 S 4 were heated in acetonitrile on subsequent addition of toluene. The crystal structure of (NEt 4 ) 2 [C 2 S 4 ] was determined by X-ray diffraction (454 independent observed reflexions, R = 0.047). Crystal data: tetragonal, a = 871.2(1) pm, c = 1566.0(3) pm, space group P4 2 /nmc, Z = 2. The [C 2 S 4]2- ion has point symmetry 4m2 (D 2d ), i.e. the dihedral angle between the two CS 2 groups is 90°. The ethyl groups of the NEt 4 + ions are disordered in two orientations.

PPh 4 [MoN(OPh) 4 ] has been prepared by reaction of PPh 4 [MoNCl 4 ] with sodium phenolate, as an orange-red crystal powder. The reactions of glycole and pinacole, respectively, with MoN(O-t-Bu) 3 and MoNCl 3 , the latter in the presence of a base, lead to the tris-chelate complexes Mo(OC 2 H 4 O) 3 and Mo(OC 2 Me 4 O) 3 , respectively. The complexes were characterized by 1 H and 13 C NMR spectroscopy, the chelate complexes in addition by X-ray structure analysis. [Mo(OC 2 H 4 O) 3 ]: Space group P2 1 /c, Z = 4, 2177 observed unique reflections, R = 0.047. Lattice dimensions at –40 °C: a = 1168.3(2), b = 716.0(1), c = 1206.1(2) pm, β = 92.84(1)°. [Mo(OC,Me 4 O) 3 ] • 2CH 2 Cl 2 : Space group P bcn, Z = 4, 1860 observed unique reflections, R = 0.049. Lattice dimensions at –80°C: a = 1772.3(1), b = 1023.8(1), c = 1600.0(2) pm. Both complexes form monomeric molecules, in which the molybdenum atoms are surrounded in a distorted octahedral fashion by the six oxygen atoms of the chelates.

The unsymmetrically substituted borazine (C 6 H 5 ) 3 B 3 N 3 H 2 [Si(CH 3 ) 3 ] has been obtained from the reaction of C 6 H 5 BCl 2 with HN[Si(CH 3 ) 3 ] 2 , and an improved synthesis of (C 2 H 5 )3B 3 N3H 2 [Si(CH 3 ) 3 ] has been developed. The reaction of the latter with an excess of BC1 3 proceeds with the ultimate formation of Cl 3 B 3 N 3 H 2 [Si(CH 3 ) 3 ], whereas the reaction with one molar equivalent of BBr 3 leads to the formation of Br(C 2 H 5 ) 2 B 3 N 3 H 2 [Si(CH 3 ) 3 ], but which is contaminated by substantial amounts of Br(C 2 H 5 ) 2 B 3 N 3 H 3 besides a diborazinyl and additional products. C 6 H 5 BBr 2 reacts with N[Si(CH 3 ) 3 ] 3 to give the aminoborane [(CH 3 ) 3 Si] 2 NBBr(C 6 H 5 ), but C 6 H 5 BCl 2 does not undergo a reaction under analogous conditions.

The new π-donor bis-(phenylenedithio)-tetrathiafulvalene (5), synthesized via phosphite coupling of 2-oxo-1,3-dithiolo-[4,5b][1,4]-benzodithiin (4), has been prepared in 5 steps starting from 1,2-dimercaptobenzene and chloroacetyl chloride. Spectroscopic and electrochemical data point to a close similarity of 5 and dibenzo-tetrathiafulvalene (DB-TTF). 5 forms a highly conducting radical-cation salt (σ RT = 100 S/cm) with AsF 6 - as counter ion.

The crystal and molecular structure of (P,P′,P″,P‴-tetraphenyl)-1,1,2,2-ethane-tetraphosphinic acid tetraisopropylester has been determined from single-crystal MoKa diffractometer data. The crystals are monoclinic with space group C 2/c, Ζ = 4, a = 2054.5(9), b = 1189.8(5), c = 1800.8(8) pm, β = 110.07(3)°. The structure was solved by direct methods and refined to R = 0.046. A 250 ps-vacuo-trajectory was calculated using the Molecular Dynamics program GROMOS. Structural data and MD results are compared to NMR spectroscopic data. A Karplus-type relation was confirmed for coupling constants 3 J PP .

Ruthenium thiolates [cpRu(PPh 3 ),(SMe)] and [cp*Ru(PPh 2 Me) 2 (SR)] (R = Me, Ph) react with sulfur dioxide in two different ways, substitution of phosphine for SO 2 , and addition of SO 2 to the thiolate ligand. The structure of [cpRu(CO)(PPh 3 )(SMe · SO 2 )] was determined by X-ray crystallography: Crystals are monoclinic, space group P2 1 /n, a = 10.26(9), b = 16.00(6), c = 14.73(6) Å, β = 90.141(5)°, Ζ = 4. The most remarkable feature is a very long (247,8 pm) S—S single bond. [cp*Ru(PPh 2 Me)(SO 2 )(SPh)] and the corresponding sulfur monoxide complex [cp*Ru(PPh 2 Me)(SO)(SPh)] undergo [3+2] cycloaddition with dimethylacetylene-dicarboxylate.

The intercalation compounds TaS 2 (pyrrole) 0.5 (1), TaS 2 (2-methylpyrrole) 0.33 (2), TaS 2 (2,5-dimethylpyrrole) (3), TaS 2 (thiazole) 0.33 (4) and TaS 2 (imidazole) 0.33 (5) are formed readily in closed systems at temperatures up to 200°C. Furane and thiophene show no tendency to intercalate in 2H–TaS 2 . Compounds 2-5 are molecular intercalation species, and deintercalation is finished at 350°C, while in 1 the pyrrole guests have been associated and thermally induced deintercalation proceeds up to 900°C with fragmentation. 1-5 can be indexed on the basis of hexagonal symmetry assuming the space group P6 3 /mmc. In 1 the stacking sequence of the host lattice TaS 2 remains unchanged while in 2, 3 and 5 a transformation from the BaB CaC stacking of 2H –TaS 2 to a sequence AbA AcA occurs. In 4 a stacking CbC BcB like in MoS 2 is realized. 1-5 show superconducting behaviour at low temperatures, 2 exhibits a pronounced metall-semiconductor transition at 220 K.

In order to elucidate specific properties of nickel-sulfur complexes, addition and substitution reactions of [Ni(′MeS 2 ′) 2 ] (1) were investigated. 1 is rapidly hydrolyzed by aqueous HCl yielding ′MeS 2 ′–H and Ni(II) ions. 1 coordinates phosphines as coligands, thioether donors decoordinate, however, simultaneously. The monophosphine complex [Ni(PMe3)(′MeS 2 ′ ) 2 ] (2) was characterized by X-ray structure determination. It contains a square-planar NiS 3 P unit and one decoordinated thioether group. Redox reactions of 1 occur with NO + and NO, yielding the binuclear nitrosyl complexes cis- and trans-[Ni(NO)(′MeS 2 ′)] 2 (3) and the disulfide [′MeS 2 '] 2 •