Volume 43, Issue 11

The preparation of sandwich-type praseodymium-bis(octaethylporphyrinate) systems [Pr(OEP) 2 ] n with different charges -1 ≤ n ≤+1 is described. The following derivatives have been isolated: Praseodymium(III)-hydrogen-bis(octaethylporphyrinate). PrH(OEP) 2 ** (1; n = -1 ) . bis(octaethylporphyrinato)praseodymium(III), Pr(OEP) 2 (2; n = 0). and bis(octaethylporphyrinato) praseodymium(III) diiodoaurate(I), [Pr(OEP) 2 ][AuI 2 ] (3; n = +1). For n = 0 or +1, one or both of the porphyrin π-electron systems have defect electrons. The compounds are identified by UV/VIS/NIR, IR and 1 H NMR spectra. The cyclic voltammetry data of the "mixed valence' species Pr(OEP) 2 in N.N-dimethylformamide are interpreted in terms of three reversible electron transfer processes. The behaviour of PrH(OEP) 2 is complicated by a deprotonation occurring during the electrochemical experiment.

Tetrabutylammonium- and tetrabutyiphosphonium-metaperiodate show 127 I solid-state NMR second order quadrupole splittings with quadrupole coupling constants in the range of 2-8 MHz. The values of e 2 qQ/h and asymmetry parameter n reveal several phase transitions of first and second order. In (n-C 4 H 9 ) 4 PIO 4 an anomalous temperature coefficient with ᾱ = 0.32 · 10 -2 [K -1 ] is observed.

Poly-arylenes, which can be doped to electronic conduction, can be perchlorinated by SCl 2 in CCl 4 in the presence of iron metal. These polymers can be modified by introduction of CN or PPh 2 groups, which can function as ligating groups for metal species.

The organorhenium(V) complexes (η 5 -C 5 Me 5 )ReX 4 (2a, X = Cl; 2b, X = Br; Me = CH 3 ) undergo stepwise dehalogenation upon treatment with various reducing agents, e.g. with HgCl 2 -activated aluminium powder, forming the isolable Re IV and Re III dimers [η 5 -C 5 Me 5 )ReCl 3 ] 2 (3a) and [η 5 -C 5 Me 5 )ReX 2 ] 2 (4a, X = Cl;4b, X = Br), respectively. The weak metal-metal single bond of 3a (307.4(0) pm; X-ray diffraction study) is disrupted upon reaction with alkynes yielding the Re III derivatives (η 5 -C 5 Me 5 )ReCl 2 (η 2 -R 1 CCR 2 ) (9a-e; R 1 , R 2 : alkyl, aryl) and novel rhenium(V)- allylidenyl complexes of type (η 5 -C 5 Me 5 )ReCl 2 [η 1 :η 3- R 1 CC(Cl)CHR 3 ] (10a-d; R 1 : alkyl. aryl; R 3 : H, alkyl). Reduction of 2a (Al/HgCl 2 ) in the presence of alkynes gives a complex reaction mixture of 9a-c, 10a - c and bis(π-alkyne) complexes [(η 5 -C 5 Me 5 )ReCl(η 2 -R 1 CCR 2 ) 2 ] + [AlCl 4 ]-(11a-c) (X-ray diffraction study of the related derivative [(η 5 -C 5 Me 5 )ReBr(η 2 -MeCCMe) 2 ] + [SbF 6 ] - ).

Distannylated bicyclo[3.2.1]octa-2,6-diene (1) with (CH 3 ) 3 Sn groups in positions exo-4 and 7 (7a), endo-4 and 7 (7b), exo-4 and 6 (7c), and probably exo-4 and endo-4 (7d) are obtained when 1 is treated first with an excess of n-BuLi/t-BuOK in alkane and then with (CH 3 ) 3 SnCl. Byproducts are monostannylated derivatives of 1 and l,4-bis(trimethylstannyl)but-2-ene (3). The formation of 7a/b/c is best understood when the two possible bicyclo[3.2.1]octa-2,6-dienyl dianions are generated as intermediates. 3,exo-4-Bis(trimethylstannyl)bicyclo[3.2.1]octa-2,6-diene (7e) is ob-tained from the corresponding dibromo derivative of 1 and (CH 3 ) 3 SnLi with 3-bromo-exo-4-trimethylstannylbicyclo[3.2.1]octa-2,6-diene (9) as an intermediate. The bicyclic stannyl com-pounds are susceptible to a 1,5-homopentadienyl shift of a (CH 3 ) 3 Sn group at relatively low temperature when the starting compound has the stannyl group in position 4 of 1 and when positions 6 or 7 are unsubstituted. Tricyclo[3.2.1.0 2.7 ]oct-3-enes with (CH 3 ) 3 Sn groups in positions exo-6 (5a), endo-6 (5b), 3 and exo-6 (10a), and 3 and endo-6 (10b) are thus obtained. On further heating, 10b gives l-trimethylstannyl-3-vinylbenzene (11). All compounds have been studied systematically by NMR spectroscopy including δ( 119 Sn), δ( 13 C), δ( 1 H), 4/5 J( 119/117 Sn- 119 Sn), n J( 119/117 Sn- 13 C) , n J( 119/117 Sn- 1 H), 1 J( 13 C- 1 H ) , and n J( 1 H- 1 H ). Among all nuclei, 119 Sn gives the most simple spectra. From the 13 C NMR spectra a series of useful increments of (CH 3 ) 3 Sn groups emerges. The most interesting coupling constants are 5 J( 119/117 Sn- 119 Sn), for which a considerable change with the dihedral angle is established, and n J( 119/117 Sn- 13 C). For n = 3 and 4 the latter are especially useful because their angular dependence leads to unambiguous signal assignments.

The lithium phosphinomethanides LiCH(X)(PMe 2 ) (X = H, PMe 2 SiMe 3 ) react with Me 3 SiCl to give silylsubstituted phosphinomethanes CH(X)(PMe 2 )(SiMe 3 ). The latter are metalated by LiR (R = t Bu, n Bu). This metalation is facilated by the presence of Me 2 NCH 2 CH 2 NMe 2 (TMEDA). X-ray structure determinations of {(TMEDA)Li[CH(PMe 2 )(SiMe 3 )]} 2 (3b) and (TMEDA){Li[C(PMe 2 )(SiMe 3 ) 2 ]} 2 (5b) show the marked influence of increasing silyl substitution on the structures of lithium phosphinomethanides: the Li-C contacts are weakened, whereas phosphorus forms additional (bridging) Li···P contacts to the second Li atom in the dimeric arrangements. In 3b, a six-membered ring in twist conformation is formed by head-to-tail dimerization. Likewise, 5b forms a six-membered ring, in this case by head-to-head dimerization. however, which may be regarded as a complex of a chelating phosphinomethyl lithiate ligand to [(TMEDA)Li] + .

Diolefincobalt(O) complexes Co(L 2 )(PMe 3 ) 2 {L 2 -[CH 2 = CHSi(OMe) 2 ] 2 O (1), [CH 2 =CHSi(OEt) 2 ] 2 O (2), (CH 2 =CHCH 2 ) 2 SiMe 2 (3), [(CH 2 =CHCH 2 ) 2 N] 2 CH 2 (4)} have been synthesized from Co(C 5 H 8 )(PMe 3 ) 3 and diolefins at ambient temperatures. Reactions with allyl ethers or with allyltin or allylphosphorus compounds involve transfer of allyl groups to the cobalt, while allylamine simply replaces cyclopentene (C 5 H 8 ) to give Co(CH 2 =CHCH 2 NH 2 )(PMe 3 ) 3 (5). Cationic cobalt(I) complexes containing olefin ligands as in 1-4 could not be obtained under conditions where norbornadiene readily gave [Co(C 7 H 8 )(PMe 3 ) 3 ]BF 4 (6). Paramagnetic 4 shows a magnetic moment μ eff = 2.0 μв (between 3.6 and 293 K), corresponding to one unpaired electron per cobalt atom. Compound 4 crystallizes in the space group P2 1 /c with Z = 4, a = 14.986(4), b = 17.223(5), c = 15.436(3) Å,β = 117.98(2)°, V = 3518.4 Å 3 . Each cobalt atom is η 4 -coordinated to a diolefin involving the smaller of two possible chelating rings. The Co-C distances range only from 2.029(6) to 2.058(6) Å for the olefin ligands, whereas Co-P bond lengths at each cobalt differ significantly: Co1-P1 2.188(2), Co1-P2 2.248(2); Co2-P3 2.185(2), Co2-P4 2.258(2) Å. This feature of two significantly different Co-L bond lengths is hitherto seen in all structurally characterized (bisolefin)CoL 2 complexes (L = PMe 3 , CH 3 CN) and can be rationalized by molecular orbital calculations (Extended Hückel) on the 17 electron model system (PH 3 ) 2 Co(C 2 H 4 ) 2 .

1,3-Di(tert-butyl)-2,4-di(2′,2′,6′,6′-tetramethylpiperidino)-1,3.2.4-azaphosphadiboretidine (6a), results from a diborylamine precursor by dehalogenation in good yield. The four-membered ring of this heterocycle is nonplanar and folded by 160° at the BB axis. The energy difference between this conformation and the planar ring is rather small. CH 3 I and the W(CO) 5 -fragment add to the phosphorus atom of 6a. However, selenium achieves a break-down of the ring. One product obtained is the selenaazadiboretidin derivative (16).

Crystals obtained from solutions of hexaethylbenzene and anhydrous Ga[GaCl 4 ] in toluene on cooling have the stoichiometry [(C 6 Et 6 )(C 6 H 5 Me)GaGaCl 4 ] · 1/2 C 6 Et 6 . a = 9.760(1), b = 21.447(2), c = 17.754(2) Å. β = 95.47(1)°; monoclinic. space group P2 1 /n. Z = 4. Each Ga(I) center is η 6 -bonded to one molecule of hexaethylbenzene and to one molecule of toluene. The two rings form an angle of 38,8°. The remaining crystal hexaethylbenzene is situated between two complex units, which are related by an inversion center located in the center of the ring.

The preparation and spectroscopic data of the complexes cis- and trans- CL 2 M(NH 2 C(CO 2 Et)=C<) , (1) (M - Pd. Pt), trans-Cl 2 Pd(NH 2 CH(CH 2 Cl)CO 2 CH 3 ) 2 (2), trans- Cl 2 Pd(NH 2 CH(CH 2 OAc)CO 2 ) 2 (3) and trans-Cl 2 Pt(Gly-β-Cl-AlaOMe) 2 (4) are reported. The structures of l a and 2 have been determined by X-ray structure analysis. Elimination of hydrogen chloride from 4 gives the dehydrodipeptide complex 5.

Ferrocenyllithium, FcLi (1), reacts with (C 5 H 4 CH 3 ) 2 TiCl 2 , CpTiCl, and Cp*TiCl 3 to give the new σ-ferrocenyl complexes (C 5 H 4 CH 3 ) 2 TiFc 2 (2), CpTiFc 3 (3) and Cp*Ti(Fc) 2 Cl (4), respectively. Treatment of Cp* 2 ZrCl 2 with FcLi yields the mono-substitution product Cp* 2 Zr(Fc)Cl (5), which has been characterized by an X-ray structure analysis. Compound 5 crystallizes in the monoclinic space group P2 1 /c (a = 1622.3(6), b = 995.0(2), c = 1664.3(6) pm; β = 94.78(3)°; Z = 4). Due to the sterically demanding pentamethylcyclopentadienyl ligands 5 contains a long zirconium-carbon bond (231.4(8) pm) and the Cp rings of the ferrocenyl substituent are tilted by 10.2°. The syntheses of CpZrFc 3 (6), Cp*HfFc 3 (7) and Cp 2 VFc 2 (8) are also described.

Benzophenone Ph 2 C=O is able to “store” the silaethene Me 2 Si=C(SiMe 3 ) 2 (1). produced from Me 2 SiX-CLi(SiMe 3 ) 2 (X = F. Br, Ph 2 PO 4 ), under formation of a [2+4] cycloadduct (2b). At about 100 °C, 2b by way of 1 transfers into the [2+2] cycloadduct of 1 and Ph 2 C=O (3b), which in the course of transformation decomposes visibly (in the absence of Me 3 SiCl) or only by traces (in the presence of Me 3 SiCl) to secondary products. In the presence of ROH (R = H. Me. tBu. MeCO) or PhN = NSiMe 3 or RN 3 (R = tBu. Me 3 Si) or 2,3-dimethylbutadiene (dmb) about 100 °C 2b and 3b form by way of 1 insertion products of 1 into the OH bond of ROH or a [2+2] cycloadduct of 1 and PhN = NSiMe 3 or [2 + 3] cycloadducts of 1 and RN 3 or a [2+4] cycloadduct and an ene reaction product of 1 and dmb. The rate constants/half lives of the first order transformation of 2b into 3b or of the first order decomposition of 2b or of 3b in the presence of reactiv traps for 1 (ROH. Me 3 SiN 3 ; benzene as solvent) are in the order of 0.3 × 10 -4 s -1 /τ 1/2 = 7 h (2b→3b; 90 °C) 3 3×10 -4 s -1 /τ 1/2 = 3/4 h (2b + traps; 90 °C), 0.4 × 10 -4 s -1 /τ 1/2 = 5 h (3b + traps. 110 °C).

Lithium triphenylsilyl-phenylphosphide (3), X = SiPh 3 , reacts with ketones to give tetraphenyl-phospholanes (6). In an initial step a phosphaalkene 5 is formed, which then adds three more phenylphosphinidene units. This second step can be performed independently, and the PhP units can be furnished by pentaphenylcyclopentaphosphane (1) if the reaction is catalyzed by lithium triphenylstannide (2), X = SnPh 3 .

Monofluoramine H 2 NF is prepared by thermolysis of H 3 NF + HF2 - -nHF and selective absorption of HF on activated KF. In the solid state H 2 NF is stable below 170 K, and immediately decomposes in NH 4 HF 2 - and N 2 by melting.

Bis(diethylamino)phosphanylacetylen reacts with N.N′-dimethyl thiourea to give 2-diethyl-amino-1,4-dimethyl-3-methylene-[1,4,2]diazaphospholidine-5-thion (2) besides the [1,3,4]thiazaphospholidine (1). The latter compound is converted into 2 by heating. Reaction of 2 with various reagents yields other members of the title compound class. All new compounds are characterized by some reactions and their NMR and IR spectra. In addition, the results of an X-ray structure analysis of 2-diethylamino-l ,4-dimethyl-3-methylene-2-thioxo-[1,4,2]diazaphos-pholidine-5-thion (5) are reported.

S,S-Diphenyl-N-(trimethylsilyl)sulfimine (1) reacts in a molar ratio of 1:1 with V(O)Cl 3 , V(O)F 3 , NbCl 5 , MoCl 5 and FeCl 3 to yield Ph 2 S=NV(O)Cl 2 (2). Ph 2 S=NV(O)F 2 (3). Ph 2 S=NNbCl 4 · CH 3 CN (4), Ph 2 S=NMoCl 4 ·CH 3 CN (5). and (Ph 2 S=NFeCl 2 ) 2 (6), respectively. The crystal structures of 2 and (dimeric) 6 are reported.

N-Acyl dimesylamines RC(O)N(SO 2 CH 3 ) 2 (3) have been prepared by reacting solid KN(SO 2 CH 3 ) 2 with neat liquid RC(O)Cl at 70-90 °C [R = C 2 H 5 , (CH 3 ) 2 CH, (CH 3 ) 3 C-CH 2 , CH 2 Cl, CHCl 2 ] or solutions of AgN(SO 2 CH 3 ) 2 in methyl cyanide with RC(O)Cl at room temperature [R = (CH 3 ) 3 C, CH 2 Cl, CHCl 2 , CCl 3 , C 6 H 5 , CH 2 =CH]. Addition of chlorine or bromine to 3 (R = CH 2 = CH) affords the corresponding compounds 3 with R = CH 2 Cl-CHCl and CH 2 Br-CHBr, respectively. By hydrolysis of 3 (R = CCl 3 ), CCl 3 C(O)NHSO 2 CH 3 (5) is obtained. The new compounds 3 and 5 are characterized by spectroscopic (NMR, MS) and analytical methods.

The reaction of TiCl 4 with (Me 3 Si) 2 S in dichloromethane yields black, insoluble, impure TiSCl 2 . In the presence of oxygen, additionally Ti 3 O(S 2 )3Cl 4 and Ti 4 O(S 2 ) 4 Cl 6 are formed. By reactions of TiSCl 2 with NEt 4 Cl and PPh 4 Cl in dichloromethane (NEt 4 ) 2 [TiSCl 2 ] and (PPh 4 ) 2 [TiSCl 4 ] · 2 CH 2 Cl 2 are formed, respectively. They were characterized by their IR spectra and by X-ray crystal structure determinations. They contain the square-pyramidal [TiSCl 4 ] 2- ion. which has a rather short Ti = S bond of 211.1(2) pm. Crystal data: (NEt 4 ) 2 [TiSCl 4 ]: tetragonal. P4/n, a = 923.9(3). c = 1406.7(2) pm. Z = 2. 966 unique observed reflexions. R = 0.053; positionally disordered ethyl groups. (PPh 4 )2[TiSCl 4 ] · 2CH 2 Cl 2 : triclinic, P1, a = 1009.7(4), b = 1115.1(3). c = 1242.1(5) pm, α = 70.27(3), β = 79.06(3), γ = 81.37(3)°, Z = 1, 1504 reflexions, β-(AsPh 4 ) 2 UCl 6 ·2CH 2 Cl 2 structure type, high R = 0.107 due to positional disorder of the anion. Addition of NEt 4 Cl or PPh 4 Cl in CH 2 Cl 2 to the primary reaction product in presence of O 2 yields (NEt 4 ) 2 [Ti 3 O(S 2 ) 3 Cl 6 ] and (PPh 4 ) 2 [Ti,O(S 2 ) 3 Cl 6 ] · CH 2 Cl 2 , respectively. Upon recrystallization of the latter from acetonitrile, (PPh 4 ) 2 [Ti 3 O(S 2 ) 3 Cl 6 ] · CH 3 CN is obtained which forms triclinic crystals with a = 1138.8(3). b = 1268.8(4), c = 2166.4(6) pm, α = 101.26(3). β = 97.21(2). γ = 109.24(2)°, Z = 2, P1 (3053 reflexions, R = 0.070). The [Ti 3 O(S 2 ) 3 Cl 6 ] 2- ion has a cluster-like structure with Ti atoms at the vertices of a triangle, with a μ 3 -O bridging atom and with tree bridging disulfide groups. Crystal data for Ti 4 O(S 2 ) 4 Cl 6 : monoclinic, C2/c, a - 917.3(2), b - 1632.5(2), c = 1268.5(2) pm, β - 108.35(2)°, Z = 4. 1009 reflexions. R = 0.027. In the Ti 4 O(S 2 ) 4 Cl 6 molecule, four Ti atoms form a distorted tetrahedron around an μ 4 -O atom; two edges of the tetrahedron are spanned by chloro bridges, four edges by disulfide bridges.

Me 2 Sn(CH 2 Li) 2 reacts with Me 2 InCl or (Me 2 NCH 2 CH 2 O) 2 InCl with formation of the new compounds Me 2 Sn(CH 2 InMe 2 ) 2 or Me 2 Sn(CH 2 In(OCH 2 CH 2 NMe 2 ) 2 ) 2 . The compounds are characterized by elemental analyses, 1 H, 13 C, 119 Sn NMR and IR spectra.

Thermal rearrangement of harmine hydroiodide (1) at 300 °C provided a new anhydronium base provisionally named as methylharmol (3). The structure was assigned on the basis of UV, IR and NMR spectral data of the base and its tetrahydro product (2). Nitration of methylharmol afforded 12-nitromethylharmol (4).