Band 49, Heft 1

The crystal structure of SbCl 4 F is reported. SbCl 4 F crystallizes in the tetragonal space group I 4̄ with a = 1278.4(6), c = 774.1(5) pm, V = 1265(1) • 10 6 pm 3 and Z = 8. Four SbCl 4 F units are linked via symmetric Sb-F-contacts forming an eight-membered heterocycles.

Black crystals of the isotypic phases LiBa 4 [Mo 2 N 7 ] and LiBa 4 [W 2 N 7 ] (monoclinic, P2/n; a = 1552.2(3)/1555.2(4), b = 642.2(1)/644.4(1), c = 1039.9(2)/1042.4(2) pm; β = 99.23(2)/99.30(3)°; Z = 4) were grown from the melt (Li, Ba 3 N 2 , Mo/W; molar ratio 20 : 5 : 1;T max = 1323 K; reaction with N 2 , 1 atm, 18 h) by cooling (20 K/h). The crystal structures contain two independent dimeric units [ MO 2 N 7 ] 9- / [W 2 N 7 ] 9- (staggered conformation; Mo/W -N -Mo/W : 173.6/173.7° and 180°/180°; Mo/W -N (term) : 180(2)-185(1)/181(3)-185(1) pm; Mo/W -N (bridg) : 195(1)/194(1) pm and 193(1)/194(1) pm).

The structure of cadmium tetrahydroborate in THF solution is fluxional on the NMR time scale and best described as Cd[(µ-H) 2 BH 2 ] 2 •nTHF as indicated by IR data. Reactions of LiBH 4 with Cd(BH 4 ) 2 in THF yield the monoanion [Cd(BH 4 ) 3 ] - exclusively, while a dilithium salt Li 2 [Cd(BH 4 ) 4 ] • 4 diglyme precipitates from diglyme solutions. Equilibria involving ICd(BH 4 ), Cdl 2 , Cdl 3 - , [Cd(BH 4 ) 3 ] - and/or [ICd(BH 4 ) 2 ] - result from Cd(BH 4 ) 2 and LiI in THF or diglyme. The solvent as well as the cation of the iodide (Cd 2+ or Li + ) influence the equilibria. This can be explained in terms of the different polarity and chelating ability of the solvents.

TiCl 3 (NPPh 3 ) and TiCl 3 (OSiPh 3 ) have been prepared from titanium tetrachloride and Me 3 SiNPPh 3 and HOSiPh 3 , respectively. Both complexes were characterized by IR spectroscopy and by crystal structure determinations. TiCl 3 (NPPh 3 ): Space group R3̄̅, Z = 6, structure analysis with 959 observed unique reflections, R = 0.039. Lattice dimensions at -68°C: a = b = 1370.5(7), c = 1845.9(9) pm. TiCl 3 (OSiPh 3 ): Space group P2 1 /c, Z = 8, structure analysis with 4549 observed unique reflections, R = 0.049. Lattice dimensions at 19°C: a = 2127.7(2), b = 947.2(1), c = 2136.8(1) pm, β = 105.081(5)°. Both complexes form monomeric molecules in which the titanium atom is tetrahedrally coordinated by three chlorine atoms, the nitrogen atom of the phosphorone iminato ligand and the oxygen atom of the silyloxy group, respectively. The bond lengths TiN of 171.9(4) pm and TiO of 171.0(3) (in average) correspond to double bonds.

The title compounds were prepared from chloro(organophosphine)metal(I) complexes and the urea homologues SeC(NH 2 ) 2 and SC(NHMe) 2 in good yields. Recrystallization of [Ph 3 ,PAg{SeC(NH 2 ) 2 }] + Cl - from DMF/CH 2 Cl 2 leads in low yield to the dinuclear complex [{µ 2 -SeC(NH 2 ) 2 }Ag{SeC(NH 2 ) 2 } 2 ] 2 2+ 2Cl - • 4DMF. The crystal structure reveals short Ag-Ag contacts and unexpectedly acute angles at the bridging selenium atom. The crystal structure of [Ph 3 PAu{SC(NHMe) 2 }] + Cl - • SC(NHMe) 2 shows short N•••Cl and N•••S contacts that probably correspond to hydrogen bonding.

The intermetallic compound Rb 3 Au 7 could be synthesized from the elements at 4 kbar, 700 °C in a modified Belt-type apparatus. The structure (Cmmm; a = 5.579(1), b = 13.267(5), c = 7.265(2) Å; Z = 2; R = 0.035, R w = 0,031) comprises three crystallographically independent Au atoms, arranged in layers along the c-axis. The shortest interatomic distances are Au -Au = 2.633Å, Au -Rb = 3.438Å and Rb -Rb = 3.622Å.

The reaction of [Mn{N(SiMe 3 ) 2 } 2 (THF)] 1 with 2,2'-bipyridine (2,2'-bipy), 1,10-phenan-throline (1,10-phen) and 4,4'-bipyridine (4,4'-bipy) yields three new complexes: [Mn(2,2'-bipy){N(SiMe 3 ) 2 } 2 ] 2, [Mn(1,10-phen){N(SiMe 3 ) 2 } 2 ] 3, and [Mn(4,4'-bipy){N(SiMe 3 ) 2 } 2 ] · THF 4. The crystal structure of 3 reveals mononuclear species with pseudo-tetrahedral coordinated manganese(II) ions. Crystal data for 3: orthorhombic, a = 1741.0(2), b = 1879.3(3), c = 1967.0(3) pm, V = 6.436(2) nm 3 , Z = 8, space group Pbca. Compound 4 crystallizes in the monoclinic system, space group P 2 1 /c; the lattice parameters are: a = 2139.5(3), b = 925.30(10), c = 1786.4(2) pm, β = 101.34(1)°, V= 3.4675(7) nm3, Z = 4. The molecular structure of 4 consists of zig-zag infinite chains, with bridging 4,4'-bipyridine groups.

[Li(12-crown-4){N(S0 2 CH 3 ) 2 }] is obtained from equimolar amounts of lithium dimesylamide and 12-crown-4 in methanol and crystallizes from acetonitrile as a 3/2 solvate. The crystallographic data of the latter at -130 °C are: monoclinic, space group P 2/n, a = 1053.4(3), b = 904.3(3), c = 2791.2(8) pm, β = 95.66(3)°, V = 2.646 nm 3 , Z = 6, D x = 1.441 Mgm -3 . Apart from CH 3 CN molecules residing in lattice cavities, the structure consists of two crystallographically independent [Li(12-crown-4){N(S0 2 CH 3 ) 2 }] ion pairs A and B in the ratio 2:1. In B, the Li and N atoms lie on a crystallographic twofold axis. In both ion pairs, Li is hexacoordinated by the four crown oxygen atoms O(C) and by one oxygen O(S) from each sulfonyl group of the anionic ligand. The coordination geometry of Li in A closely resembles that of Cu II in the known structure of [Cu(12-crown-4)Cl 2 ] and can be pictured as a distorted octahedron, where two cis sites are occupied by the O(S) atoms and the remaining vertices by the four oxygens of the macrocycle, which displays a [4 8] conformation. The lithium atom, the two O(S) and two O(C) atoms are arranged in an approximately square-planar pattern with L i-O (S) 203.6 and 205.1, Li-O(C) 206.9 and 219.1 pm, trans angles of 173.7 and 174.8°, and cis angles in the range 87.1 -93.6°. The angle between the remaining two Li -O(C) bonds with distances 214.7 and 221.5 pm is only 146.5° compared with 180° in an ideal octahedron. In ion pair B, the coronand assumes a [3 3 3 3] conformation close to C 4 symmetry, as observ­ ed e. g. in the known structures of [Li(12-crown-4)NCS] with a square-pyramidal 0 4 N-coordination and [Ca(12-crown-4)(H 2 0) 4 ]Cl 2 · 4 H 2 O with a square-antiprismatic 0 8 -geometry. The coordination polyhedron in B can be viewed as an incomplete cube in which two vertices related by a face diagonal are unoccupied. Important bond lengths and angles in B are: L i-O(S) 216.8, L i-O(C) 214.0 and 228.7pm; O(S) -L i-O (S) 82.0, O(C) -L i-O(C) 75.7/76.3 for adjacent and 120.4/121.9° for opposite ring oxygens.

Acylic silylated phosphazenes of the type HN(PR 2 NSiMe 3 ) 2 (1) react quantitatively with molecules MMe 3 (M = Al, Ga, In) under ring formation and CH 4 evolution. The ring compounds N(PPh 2 NSiMe 3 ) 2 AlMe 2 (2 a) and N(PPh 2 NSiMe 3 ) 2 InMe 2 (4 a) have been investiga­ ted by X-ray structure determination. 2a and 4a crystallize in the space groups P 1̄ and P 3 1 , respectively; they show different conformations regarding the cyclohexane framework. NMR spectroscopy of the nuclei in the chelating phosphazene ligand indicates decreasing Lewis acidity of the metal containing fragments in the series AlMe 2 ≥ GaMe 2 > InMe 2 .

Low spin di(bromo)phthalocyaninatometalates of tervalent iron, ruthenium and osmium ([MBr 2 Pc 2- ] - ) are formed by the reaction of [FeBrPc 2- ] or H[MBr 2 Pc 2- ] (M = Ru, Os) with excess bromide in DMF or THF and isolated as ( n Bu 4 N) + salts. The electronic spectra show the typical π- π*- transitions (B, Q, N region) of the Pc 2- ligand together with a number of extra bands due to trip-multiplett and (Pc, Br → M)CT transitions. ν s (MBr) is observed in the resonance Raman (RR) spectrum (RR enhanced for M = Fe, Ru) at 161 cm -1 (Fe), 183 cm -1 (Ru) and 192 cm -1 (Os), ν as (MBr) at 251 cm -1 (Fe), 234 cm -1 (Ru) and 218 cm-1 (Os) in the FIR spectra. The RR spectra obtained by excitation at low absorbance between the B and Q region are dominated by the intraconfigurational " Γ 7 →Γ 8" transition due to spin orbit splitting of the 2 T 2g ground state for Fe at 583 cm -1 , Ru at 1026/1050 cm -1 and Os at 3131 cm -1 . In the MIR resp. NIR spectra vibronically induced transitions are observed for the Ru or Os complex.

The cesium polytelluridostannate(IV) Cs 2 SnTe 4 has been prepared by methanolothermal reaction of Cs 2 CO 3 with Sn and Te at 190 °C. The crystal structure contains chain anions 1 ∞ [SnTe 2- 4 ] in which individual SnTe 4 tetrahedra are linked via Te -Te bonds of length 2.814(3) Å. Weak Te∙∙∙Te secondary bonds of length 3.631(3)-3.663(3) Å connect neighbouring chains into a framework structure. Nine Te atoms from three chain anions participate in the coordination sphere of the cesium cation.

Gd 2 (SO 3 ) 3 • 3 H 2 0 is obtained by passing gaseous SO 2 through a suspension of Gd 2 O 3 in H 2 O at room temperature until a clear solution is formed. Single crystals are obtained by heating to 70(2) °C for 6 days. The compound crystallizes in the triclinic space group P 1 with a = 6.499(6), b = 6.621(3), c = 6.954(3) Å, α = 110.71(5), β = 90.54(3), γ = 106.05(1)° and Z = 1. The two crystallographically different gadolinium atoms are both coordinated by eight oxygen atoms forming distorted square antiprisms. Gd(l) is coordinated by six O atoms of sulfite ligands and two O atoms of water, while Gd(2) is surrounded by seven O atoms of SO 3 and one of H 2 O. Gd-O-bond lengths vary between 2.31(3) and 2.50(3) Å.

The substituted phenyl, 1-naphthyl or the 9-anthrylmethyl esters of the 2-methyl-(or 2-phenyl)-2,3-alkadienoic acids (see 4 a -g , 9 a -d and 12a,b) are synthesized by condensation of the allenic acids 2 a -d with the substituted phenols 3 a -g , with 1-naphthol (8) or with 9-anthrylmethanol (11) in the presence of dicyclohexyl carbodiimide (DCC) and a catalytic amount of 4-dimethylaminopyridine (DMAP). An alternative route is the reaction of the acid chloride la with the phenols 3 a -c (see formation of 4 a -c) in the presence of triethylamine. All these compounds (except 12a) undergo the intramolecular Diels-Alder (IMDA)-reaction to form the tricycles 6 a -g , 10 a-d and 13. The enol ether 6a is hydrolized during chromatography to give the tricyclic ketone 7. The influence of the geminal methyl group on the rate of the IMDA-reaction is investigated. 9-Anthryl-and (2,4,6-cycloheptatrien-1-on-2-yl)-2-methyl-2,3-butadienoate (15, 17), formed by reaction of 2-methyl-2,3-butadienoyl chloride (1a) with 9-anthrone (14) and 2-tropolone (16) isomerise spontaneously to the IMDA-products 19 and 18.

Single pot reactions of FeCl 2 ∙4H 2 O with the tetradentate thioether-thiol 'S 4 -H 2 ' = 1,2-bis(2-mercaptophenylthio)ethane, phosphines such as PEt 3 , PPr 3 or PBu 3 , and a ca. 40-fold excess of N 2 H 4 ∙H 2 O yield, in the presence of air, diazene complexes of the general formula [µ-N 2 H 2 {Fe(PR 3 )('S 4 ')} 2 ]. In contrast to previous syntheses of diazene complexes, the yields can excel 80%, and the syntheses can be carried out on a 10 g scale. [µ-N 2 H 2 {Fe(PPr 3 )('S 4 ')} 2 ], 1 and [µ-N 2 H 2 {Fe(PEt 3 )( 'bu S 4 ')} 2 ], 2 were characterized by X-ray structure analysis. 2 contains 'bu S 4 ' 2− = 1,2-bis(3,5-ditertiarybutyl-2-mercaptophenylthio)-ethane(2-), which is the tertiary-butyl derivative of 'S 4 ' 2− . 1 and 2 contain trans-HN=NH which bridges enantiomeric [Fe(PPr 3 )('S 4 ')] or [Fe(PEt 3 )( 'bu S 4 ')] fragments. HN=NH is stabilized by 4c - 6 e − - π bonds, strong tricentric N − H∙∙∙(S) 2 bridges, and steric shielding. NMR studies show that centrosymmetric 1 isomerizes in solution at temperatures around 0 °C in order to give a diastereomerie diazene complex which is also centrosymmetric. The diastereomerism is traced back to bridging the chiral [Fe(PPr 3 )('S 4 ')] fragments by trans-HN=NH in a different way. The two different bridging modes are verified by X-ray structure analyses of analogous ruthenium complexes. Because this new type of diastereomerism is basically caused by a different position only of the N − H∙∙∙(S) 2 bridges, it is termed hydrogen bridge diastereomerism. A mechanism for the isomerization is suggested. 1 exhibits three anodic waves in the cyclovoltammogram. The second wave indicates formation of the dication [1] 2+ , which is a redox isomer of the diprotonated (and as yet hypothetical) dinitrogen complex [µ-N 2 {Fe(PPr 3 )('S 4 ')} 2 ]. The significance of [1] 2 + and of its Lewis basic thiolate donors with respect to electrochemical reduction of molecular dinitrogen under mild conditions is discussed.

Amine adducts of diorganomagnesium compounds MgR 2 (L) are soluble in hydrocarbons and therefore valuable synthons for reactions in non-polar solvents. In this way unsymmetrically substituted derivatives MgRR'(L) become available by substituting one organic group by a different carbanion via acid-base reactions, according to eq. (1): R 2 Mg(L) + HR' -> RR'Mg(L) + HR (1) with HR' being stronger CH-acids than HR. Using the amin adducts R 2 Mg(L) (R = Me, Et) with chelating amines (L = tetramethyl­ ethylenediamine, TMEDA, pentamethylethylenetriamine, PMDTA) and the strong CH-acids cyclopentadiene, indene, fluorene and alkynes the following compounds have been synthesized and their structures derived by X-ray analyses: MgMe(η 3 -cyclopentadienyl)(tmeda) (1), MgMe(η 3 -indenyl)(tmeda) (2), MgMe(η 1 -fluorenyl)(tmeda) (3), [Mg 2 Me 2 (pmdta) 2 ] 2+ [fluorenyl] − 2 benzene (4) and [Mg 2 Et(phenylethynyl) 3 (tmeda)] 2 ∙ benzene (5). It is remarkable, that cyclopentadienyl, indenyl, and fluorenyl ligands have a lower hapticity than η 5 to the metal, due to steric repulsion by the other ligands. In 4 the bulky tridentate base PMDTA prevents any direct interaction between the fluorenide anion and magnesium, giving solvens separated ion pairs with the unusual and hitherto rare example of an organomagnesium cation [Mg 2 Me 2 (pmdt) 2 ] 2+ . The 1:3 compound 5 has a more complicated structure, related to that of alkali metal alkynyl magnesates.

1,3-Dimethyl-1,3-diaza-2-fluoro-5,6-benzo-1,3,2-phosphorinane-4-one (1) reacted with (COD)PtCl 2 (COD = 1,5-cyclooctadiene) or K 2 PtCl 4 to give the cis-dichloro-platinum(II) complex (2). The reactions of 1 with the tetracarbonyl norbornadiene derivatives of Cr, Mo and W furnished the complexes 3 - 6 . In the case of the chromium and tungsten complexes the trans-isomers 3 and 6 were formed, due to a cis-trans-isomerization. Room temperature and low temperature 31 P NMR spectra of a mixture of 5 and 6 show no significant temperature dependence of the cis-trans equilibrium. The reaction of 1 with the pentacarbonyl tetrahydrofuran derivative of W led to the product 7. The spirophosphoranes 8 and 9 were obtained in low yields. The analogous reactions of 10, 15 and 20 with (COD)PtCl 2 and the tetracarbonyl norbornadiene derivatives of Cr and Mo furnished the coordination compounds 11-14, 16-18, 21 and 23. In the case of all chromium complexes only the trans-isomers 11,16 and 21 were formed, whereas in the case of molybdenum cis-trans-isomer mixtures 12 and 13, as well as 17 and 18 were obtained. An attempt to obtain the cis-isomer of the molybdenum complex 22 failed. In the case of platinum the expected cis-complexes 14 and 23 were formed, while the attempted synthesis of 19 was unsuccessful. All these results are interpreted in terms of both steric and electronic factors. The ligands 1, 10, 15 and 20 coordinate via phosphorus. The validity of the concept of hard and soft acids and bases (HSAB) was confirmed. The characterization of 2 - 7 , 11-14, 16-18, 21 and 23 rests, especially, on their 1 H, 13 C and 31 P NMR spectra, and their mass and infrared spectra. 31 P - 31 P coupling constants 2 J(PP) for the cis-coordinated complexes 4, 5 and 14 involving two equivalent phosphorus ligands are also reported.

Synthetic procedures are described that allow access to a number of new Rh(III) complexes with the tetradentate bis-amide ligand N,N'-bis(2'-pyridinecarboxamide)-1,8-naphthalene (LH 2 ). These complexes have the formulae Rh(LH 2 )Cl 3 , Na[RhLX 2 ] • H 2 O (X = Cl, CN) and [RhLA 2 ]ClO 4 (A = pyridine, 1-methylbenzotriazole). The compounds have been characterized by elemental analyses, conductivity measurements, X-ray powder patterns, spectroscopic (IR, UV/VIS, 1 H NMR) studies and electrochemical methods. The neutral amide behaves as a bis-bidentate ligand in the oligomeric or polymeric, octahedral complex Rh(LH 2 ,)Cl 3 . Monomeric, trans octahedral structures are assigned for the complexes of L 2− in the solid state; the doubly deprotonated ligand acts as a tetradentate chelating agent with the four nitrogens as ligating atoms.

In toluene, bis(pentafluorophenyl)cadmium(II) and thiols RSH (R = Bu t , 2,4,6-Pr i 3 C 6 H 2 , 2,4,6-Bu t 3 C 6 H 2 ) react to give soluble pentafluorophenyl cadmium thiolates [(Cd(C 6 F 5 )(SR)} n ] The compounds [{Cd(C 6 F 5 )(SBu t )} 4 ] (1) ∙ 0.5 C 6 H 5 CH 3 , [ {Cd(C 6 F 5 )(SC 6 H 2 Pr i 3 -2,4,6)} n ] (2) ∙ ca. 0.25n C 6 H 5 CH 3 , and [{Cd(C 6 F 5 )(SC 6 H 2 Bu t 3 -2,4,6)} n ] (3) ∙ ca. 0.25 n C 6 H 5 CH 3 have been prepared in 65, 59 and 78% yield, respectively. 1 ∙ 0.5 C 6 H 5 CH 3 crystallizes in the triclinic space group P1̄ with a = 11,635(1)Å, b = 11.583(1)Å, c = 21.480(2)Å, α = 82.12(1)°, β = 76.26(1)°, γ = 89.35(1)°, and Z = 2. 1 is a cubane-type complex with a {Cd 4 (μ 3 -SBu t ) 4 } 4+ core. Each Cd atom is coordinated by three bridging thiolato ligands and one terminal C 6 F 5 group (Cd - S 2.62 Å, Cd - C 2.15 Å (mean values)). The central C atoms of the Bu t S − ligands of 1 show a remarkable low-field shift o f their 13 C NMR resonance (12.3 ppm relative to the value of the free thiol). A characteristic spectral feature of (Cd(C 6 F 5 ) } + complexes is the large value of the coupling constant 2 J ( 19 F , 13 C) of the ipso-C atom (1, 2: 68 Hz; 3: 67 Hz). The complexes [Cd(C 6 F 5 )(SR) + H] + , [Cd(SR) 2 + H] + , and [Cd 2 (SR) 3 ] + were identified in the Cl mass spectra (iso-butane) of 2 and 3.

Excoecaria factor O 1 -the daphnane type polyfunctional diterpene ester 5 β-hydroxy-6 α,7 α-epoxyresiniferonol-9,13,14-orto-(2,4,6-decatrienoate) -may be obtained in reason­ able amounts from the latex of Excoecaria oppositifolia from South East Asia. O 1 was partially hydrogenated with H 2 -Pd/C to yield, by saturation of the three double bonds in the orthoester, and of ⊿ 15,16 in the diterpene moiety, the new 15,16-dihydro derivative of simplexin. The latter is the well known daphnane prototype of polyfunctional diterpene esters occurring in Euphorbiaceae and Thymelaeaceae. 15,16-Dihydrosimplexin (DHS) showed pro­nounced irritant and tumor promoting activities. By analogous hydrogenation of O1 with a mixture of 1 H 2 / 3 H 2 a selectively labeled [ 3 H]DHS was obtained that exhibited a particularly high specific activity of 30 Ci/mmole. Thus it is considered most appropriate for use to study the toxicokinetics and -dynamics of daphnane type diterpene esters. To device an alternative of 3 H-labeling of DHS or simplexin (SIM) in position 20 of the diterpene moiety DHS-5-benzoate was oxidized by pyridinium chlorochromate. The resultant 20-aldehyde was reduced by sodium borohydride to reconstitute DHS-5-benzoate and, after deprotection, DHS. This route appears appropriate to prepare similarly [20- 3 H]DHS as well as [20- 3 H]SIM using sodium [ 3 H]borohydride.

Five cerebrosides B-1−B-4 were isolated from the fraction B, obtained from the latex of Euphorbia characias L. On the basis of spectral evidences and chemical reactions they were characterized as (2S, 3S, 4R, 8Z)-1-O-(β-D-glucopyranosyl)-2N-[(2'R)-2'-hydroxytetracosenoyl]-8 (Z)-octadecene-1,3,4-triol-2-amino (B-1), (2S, 3S, 4R, 8Z)-1-O-(β-D-glucopyranosyl)-2 N-[(2'R)-2'-hydroxyhexacosenoyl]-8(Z)-octadecene-1,3,4-triol-2-amino(B-2), (2 S, 3 S,4 R, 8 Z)-1-O-(β-D-glucopyranosyl)-2N-[(2'R)-2'-hydroxyoctacosenoyl]-8 (Z)-octa-decene-1,3,4-triol-2-amino (B-3), (2 S, 3 S, 4R, 8Z)-1-O-(β-D-glucopyranosyl)-2N-[(2'R)-2'-hydroxyhexacosanoyl]-8 (Z)-octadecene-1,3,4-triol-2-amino (B-3a), (2S, 3S, 4R, 8Z)-1-O-(β-D-glucopyranosyl)-2 N-[(2'R)-2'-hydroxyheptacosanoyl]-8 (Z)-octadecene-1,3,4-triol-2-amino (B-4). Reversed phase column flash chromatography was effective for the isolation of the cerebrosides. FAB-MS spectrometry, 1 H NMR, 13 C NMR analyses and DQF-COSY and 1 H-detected HMQC (single bond and multiple bond) experiments and chemical reactions were useful in providing informations for the structure elucidation.

We report the synthesis of 3,5-di-tert-butylstyrene (5). The alkylation of toluene with tertbutylchloride establishes the 1,3,5-substitution pattern. A Wittig reaction introduces the C 1 unit. This and similar bulky styrene derivatives will be used as special building blocks for polymer design.