Functionalized Organotin‐Chalcogenide Complexes That Exhibit Defect Heterocubane Scaffolds: Formation,Synthesis, and Characterization

The synthesis of new functionalized organotin‐chalcogenide complexes was achieved by systematic optimization of the reaction conditions. The structures of compounds [(R^{1, 2}Sn)₃S₄Cl] ( 1 , 2 ), [((R²Sn)₂SnS₄)₂(μ‐S)₂] ( 3 ), [(R^{1, 2}Sn)₃Se₄][SnCl₃] ( 4, 5 ), and [Li(thf)_n][(R³Sn)(HR³Sn)₂Se₄Cl] ( 6 ), in which R¹=CMe₂CH₂C(O)Me, R²=CMe₂CH₂C(NNH₂)Me, and R³=CH₂CH₂COO, are based on defect heterocubane scaffolds, as shown by X‐ray diffraction, ¹¹⁹Sn NMR spectroscopy, and ESI mass spectrometry analyses. Compounds 4 , 5 , and 6 constitute the first examples of defect heterocubane‐type metal‐chalcogenide complexes that are comprised of selenide ligands. Comprehensive DFT calculations prompted us to search for the formal intermediates [(R¹SnCl₂)₂(μ‐S)] ( 7 ) and [(R¹SnCl)₂(μ‐S)₂] ( 8 ), which were isolated and helped to understand the stepwise formation of compounds 1 – 6 .     

Organotin–Oxido Cluster‐Based Multiferrocenyl Complexes Obtained by Hydrolysis of Ferrocenyl‐Functionalized Organotin Chlorides

Three organotin–oxido clusters were formed by hydrolysis of ferrocenyl‐functionalized organotin chloride precursors in the presence of NaEPh (E=S, Se). [R^FcSnCl₃?HCl] ( C ; R^Fc = CMe₂CH₂C(Me)?N?N?C(Me)Fc) and [SnCl₆]^2? formed {(R^FcSnCl₂)₃[Sn(OH)₆]}[SnCl₃] ( 3 a ) and {(R^FcSnCl₂)₃[Sn(OH)₆]}[PhSeO₃] ( 3 b ), bearing an unprecedented [Sn₄O₆] unit, in a one‐pot synthesis or stepwise through [(R^FcSnCl₂)₂Se] ( 1 ) plus [(R^FcSnCl₂)SePh] ( 2 ). A one‐pot reaction starting out from FcSnCl₃ gave [(FcSn)₉(OH)₆O₈Cl₅] ( 4 ), which represents the largest Fc‐decorated Sn/O cluster reported to date.     

Molecular Thorium Trihydrido Clusters Stabilized by Cyclopentadienyl Ligands

Hydrogenolysis of alkyl‐substituted cyclopentadienyl (Cp^R) ligated thorium tribenzyl complexes [(Cp^R)Th(p‐CH₂‐C₆H₄‐Me)₃] ( 1 – 6 ) afforded the first examples of molecular thorium trihydrido complexes [(Cp^R)Th(μ‐H)₃]_n (Cp^R=C₅H₂(^tBu)₃ or C₅H₂(SiMe₃)₃, n=5; C₅Me₄SiMe₃, n=6; C₅Me₅, n=7; C₅Me₄H, n=8; 7 – 10 and 12 ) and [(Cp^#)₁₂Th₁₃H₄₀] (Cp^#=C₅H₄SiMe₃; 13 ). The nuclearity of the metal hydride clusters depends on the steric profile of the cyclopentadienyl ligands. The hydrogenolysis intermediate, tetra‐nuclear octahydrido thorium dibenzylidene complex [(Cp^ttt)Th(μ‐H)₂]₄(μ‐p‐CH‐C₆H₄‐Me)₂ (Cp^ttt=C₅H₂(^tBu)₃) ( 11 ) was also isolated. All of the complexes were characterized by NMR spectroscopy and single‐crystal X‐ray analysis. Hydride positions in [(Cp^Me4)Th(μ‐H)₃]₈ (Cp^Me4=C₅Me₄H) were further precisely confirmed by single‐crystal neutron diffraction. DFT calculations strengthen the experimental assignment of the hydride positions in the complexes 7 to 12 .     

Untersuchungen zur Bildung silylierter iso-Tetraphosphane aus P2-chlorierten Triphosphanen und Li-Phosphiden

Investigations on the Formation of Silylated iso-Tetraphosphanes We investigated the formation of iso-tetraphosphanes by reacting [Me(Me₃Si)P]₂PCl 4 , Me(Me₃Si)P? P(Cl)? P(SiMe₃)₂ 8 , Me(Me₃Si)P? P(Cl)? P(SiMe₃)(CMe₃) 9 , [Me(Me₃Si)P]₂PCl 20 , Me₃C(Me₃Si)P? P(Cl)? P(SiMe₃)₂ 21 , and [MeC(Me₃Si)P]₂PCl 22 with LiP(SiMe₃)Me 1 , LiP(SiMe₃)₂ 2 , and LiP(SiMe₃)CMe₃ 3 , respectively, to elucidate possible paths of synthesis, the influence of substituents (Me, SiMe₃, CMe₃) on the course of the reaction, and the properties of the iso-tetraphosphanes. These products are formed via a substitution reaction at the P²Cl group of the iso-triphosphanes. However, with an increasing number of SiMe₃ groups in the triphosphane as well as in reactions with LiP(SiMe₃)Me, cleaving and transmetallation reactions become more and more important. The phosphides 1,2, and 3 attack the PC1 group of 4 yielding the iso-tetraphosphanes P[P(SiMe₃)Me]₃ 5, [Me(Me₃Si)P]₂P? P(SiMe₃)₂ 6 and [Me(Me₃Si)P]₂P? P(SiMe₃)CMe₃ 7. I n reactions With 8 and 9, LiP(SiMe₃)Me causes bond cleavage and mainly leads to Me(Me₃Si)P? P(Me)? P(SiMe₃)₂ 13 and Me(Me₃Si)P? (Me)? P(SiMe₃)CMe₃ 16, resp., and to monophosphanes; minor products are [Me(SiMe₃)P]₂P? P(SiMe₃)₂ 6 and [Me(Me₂Si)P]₂P? P(SiMe₃)CMe₂ 7. LiP(SiMe₃)₂ 2 and LiP(SiMe₃)CMe₂ 3 with 8 and 9 give Me(Me₃,Si)P? P[P(SiMe₃)₂]₂ 10, Me(Me₂Si)P? P[P(SiMe₃)CMe₂]? P(SiMe₃)₂ 11, and Me(Me₃Si)P? P[P(SiMe₃)CMe₃]₂ 12 as favoured products. With 20, LiP(SiMe₃)₂ 2 forms P[P(SiMe₃)₂]₃ 28. Bond cleavage products are obtained in reactions of 20 with 1 and 2, of 21 with 1, 2, and 3, and of 22 with 1 and 2. P[P(SiMe₃)CMe₃]₃ 23 is the main product in the reaction of 22 with LiP(SiMe₃)CRle₂ 3. In the reactions of 22 with 1, 2, and 3 the cyclophosphanes P₃(CMe₃)₂(SiMe₃)25, P₄[P(SiMe₃)CMe₃]₂(CMe₃)₂ 26, and P₅(CMe₃)₄(SiMe₃) 27 are produced. The formation of these rom- pounds begins with bond cleavage in a P- SiMe, group by means of the phosphides. The thermal stability of the iso-tetraphosphanes decreases with an increasing number of silyl groups in the molecule. At 20O°C compounds 5, 7, and 23 are crystals; also 6 is stable; however, 10, It, 12, and 28 decompose already.     

Manganese(II) Complexes with Bridging Selenidoarsenate(III) Anions [AsSe2(Se2)]3− and [(AsSe2)2(μ‐Se2)]4−

Solvothermal reaction of [MnCl₂(terpy)] with elemental As and Se at a 1:1:2 molar ratio in H₂O/trien (10:1) at 150 °C affords the linear trimanganese(II) complex [{Mn(terpy)}₃(μ‐AsSe₄)₂] ( 1 ). The tridentate [AsSe₂(Se₂)]^3? anions of 1 chelate the terminal {Mn(terpy)}²⁺ fragments and bridge these through their remaining Se atom to the central {Mn(terpy)}²⁺ moiety. Weak interactions of Mn1···Se and Mn3···Se bonds with length 2.914(7) and 3.000(7) Å link the molecules of 1 into infinite chains. Treatment of [MnCl₂(cyclam)]Cl with As and Se at a 1:1:2 molar ratio in superheated H₂O/CH₃OH (1:1) at 150 °C yields the dinuclear complex [{Mn(cyclam)}₂ (μ‐As₂Se₆)] ( 2 ), whose novel [(AsSe₂)₂(μ‐Se₂)]^4? ligands bridge the Mn^II atoms in a μ‐1κ²Se¹, Se²: 2κ²Se⁵,Se⁶ manner.     

Übergangsmetallphosphidokomplexe. XI. Diphosphenkomplexe des Typs (R3P)2Ni[η2-(PR′)2] und phosphidoverbrückte Nickel(I)-Komplexe des Typs [R3PNiP(SiMe3)2]2 (Ni?Ni)

Transition Metal Phosphido Complexes. XI. Diphosphene Complexes of the Type (R₃P)₂Ni[η²-(PR′)₂] and Phosphido-Bridged Nickel(I) Complexes of the Type [R₃PNiP(SiMe₃)₂]₂(Ni? Ni) From reactions of complexes of the type (R₃P)₂NiCl₂ 1 (R = Me a , Et b , nBu c , iBu d , Ph e , iPr f , Cy g ) with LiP(SiMe₃)₂ in a 1:2 molar ratio the diphosphene complexes (R₃P)₂Ni[η²-(PSiMe₃)₂] 4a–c and the phosphido-bridged nickel(I) complexes [R₃PNiP(SiMe₃)₂]₂ (Ni? Ni) 7a–g are available. Using low temperature n.m.r. measurements the monosubstitution products (R₃P)₂NiClP(SiMe₃)₂ 2a–c and the nickel(0) diphosphane complexes R₃PNi[η¹-P₂(SiMe₃)₄] 6a–g can be detected as intermediates. In reactions in a 1:1 molar ratio the formation of the diphosphorus complexes [(R₃P)₂Ni]₂P₂ 9b, 9c is n.m.r. spectroscopically detectable. 1b reacts with LiP(SiMe₃)CMe₃ to give first the nickel(0) diphosphane complex Et₃PNi[η¹-P(SiMe₃)CMe₃? P(SiMe₃)CMe₃] 10 , which can be isolated at low temperatures, finally yielding (Et₃P)₂Ni[η²-(PCMe₃)₂] 11 and [Et₃PNiP(SiMe₃)CMe₃]₂ (Ni? Ni) 12. 11 as well as (Et₃P)₂Ni[η²-(PPh)₂] 14 can also be obtained reacting 1b with R′P(SiMe₃)₂ (R′ = CMe₃, Ph). The best yields of diphosphene complexes result from [2+1] cyclocondensation reactions of 1a–c with P₂(SiMe₃)₄ to give 4a–c and of 1b with [P(SiMe₃)CMe₃]₂ to give 11 . N.m.r. and mass spectral data are reported.     

Synthesen und Kristallstrukturen neuer chalkogenido‐verbrückter Niob‐Kupfer‐Cluster

Syntheses and Crystal Structures of Novel Chalcogenido‐bridged Niobium Copper Clusters In the presence of tertiary phosphines, the reaction of NbCl₅ and Copper(I) salts with Se(SiMe₃)₂ (E = S, Se) affords the new chalcogenido‐bridged niobium‐copper cluster compounds ( 1 ) and [NbCu₄Se₄Cl (PPh₃)₄] ( 2 ). Using E(R)SiMe₃ (E = S, Se, R = Ph, ⁿPr) instead of the bisilylated selenium species leads to the compounds [NbCu₂(SPh)₆(PMe₃)₂] ( 3 ), [NbCu₂(SPh)₆(PⁿPr₃)₂] ( 4 ), [NbCu₂(SePh)₆(PMe₃)₂] ( 5 ), [NbCu₂(SePh)₆(PⁿPr₃)₂] ( 6 ), [NbCu₂(SePh)₆(PⁱPr₃)₂] ( 7 ), [NbCu₂(SePh)₆(P^tBu₃)₂] ( 8 ), [NbCu₂(SePh)₆(PⁱPr₂Me)₂] ( 9 ), [NbCu₂(SePh)₆(PPhEt₂)₂] ( 10 ), [Nb₂Cu₂(SⁿPr)₈(PⁿPr₃)₂Cl₂] ( 11 ) and [Nb₂Cu₆(SⁿPr)₁₂(PⁱPr₃)₂Cl₄]·2 CH₃CN ( 12 ·2 CH₃CN). By reacting Cu^I salts and NbCl₅ with the monosilylated selenides Se(^tBu)SiMe₃ and Se(ⁱPr)SiMe₃ which have a weak Se–C bond the products [Nb₂Cu₆Se₆(PⁱPr₃)₆Cl₄] ( 13 ), [Nb₂Cu₄Se₂(SeⁱPr)₆(PⁿPr₃)₄Cl₂] ( 14 ) and [Nb₂Cu₆Se₂(SeⁱPr)₁₀(PEt₂Me)₂Cl₂]·DME ( 15 ) are formed which contain selenide as well as alkylselenolate ligands. The molecular structures of all of these new compounds were determined by single crystal X‐ray diffraction measurements.     

Novel convenient synthesis and chemoselective derivatization of 1-sila-4-stannacyclohexanes

Treatment ofR¹R²Si[(CH₂)₂SnR³ ₃]₂ with R³Li in THF at 0 °C followed by warming to roomtemperature gave 1-sila-4-stannacyclohexanesR¹R²Si[(CH₂)₂]₂SnR³ ₂ in good yields. This novel cyclization was applicable to the preparation of 6-sila-3,9-distannaspiro[5.5]undecane. Chemoselective substitution of the phenyl group on silicon or tin of the silastannacyclohexanes was achieved by treatment with an equimolar amount of trifluoromethanesulfonic acid followed by the addition of a Grignard reagent.     

Synthesis,Structures, and Light‐Induced Transformation of Keto‐Functionalized Selenidogermanate Complexes

A double‐decker (DD) type selenidogermanate complex with C=O functionalized organic decoration, [(R¹Ge₄)Se₆] ( 1 , R¹ = CMe₂CH₂COMe), was synthesized by reaction of R¹GeCl₃ with Na₂Se, and subsequently underwent a light‐induced transformation reaction to yield [Na(thf)₂][(RGe^IV)₂(RGe^III)(Ge^IIISe)Se₅] ( 2 ). Similar to the observations reported previously for the Sn/S homologue of 1 , the product comprises a mixed‐valence complex with a newly formed Ge–Ge bond. However, different from the transformation of the tin sulfide complex, the selenidogermanate precursor did not produce a paddle‐wheel‐like dimer of the DD type structure, but led to the formation of a noradamantane (NA) type architecture, which has so far been restricted to the Si/Se and Ge/Te elemental combination.     

Further studies on organonickel compounds: the synthesis of some new alkyl-, acyl- and cyclopentadienyl-derivatives and the crystal structure of trans-[Ni(CH2SiMe3)2(PMe3)2]

The complex [NiCl₂(PMe₃)₂] reacts with one equivalent of mg(CH₂CMe₃)Cl to yield the monoalkyl derivative trans-[Ni(CH₂CMe₃)Cl(PMe₃)₂], which can be carbonylated at room temperature and pressure to afford the acyl [Ni(COCH₂CMe₃)Cl(PMe₃)₂]. Other related alkyl and acyl complexes of composition [Ni(R)(NCS)(PMe₃)₂] (R = CH₂CMe₃, COCH₂CMe₃) and [Ni(R)(η-C₅H₅)L] (L = PMe₃, R = CH₂CMe₃, COCH₂CMe₃; L = PPh₃, R = CH₂CMe₂Ph) have been similarly prepared. Dialkyl derivatives [NiR₂(dmpe)] (R = CH₂SiMe₃, CH₂CMe₂Ph; dmpe = 1,2-bis(dimethylphosphine)ethane, Me₂PCH₂ CH₂PMe₂) have been obtained by phosphine replacement of the labile pyridine and NNN′N′-tetramethylethylenediamine ligands in the corresponding [Ni(CH₂SiMe₃)₂(py)₂] and [Ni(CH₂CMe₂Ph)₂(tmen)] complexes. A single-crystal X-ray determination carried out on the previously reported trimethylphosphine derivative [Ni(CH₂SiMe₃)₂(PMe₃)₂] shows the complex belongs to the orthorhombic space group Pbcn, with a = 14.345(4), b = 12.656(3), c = 12.815(3) Å, Z = 4 and R 0.077 for 535 independent observed reflections. The phosphine ligands occupy mutually trans positions P-Ni-P 146.9(3)° in a distorted square-planar arrangement.     

Übergangsmetallphosphidokomplexe. XII. Diphosphenkomplexe (DRPE)Ni[η2-(PR′)2] und die Struktur von (DCPE)NiP(SiMe3)2

Transition Metal Phosphido Complexes. XII. Diphosphene Complexes (DRPE)Ni[η²-(PR′)₂] and the Structure of (DCPE) NiP (SiMe₃)₂ LiP(SiMe₃)₂ reacts with the complexes (DRPE)NiCl₂ 1 (DRPE = R₂PCH₂CH₂PR₂; R = Et: DEPE a ; R = Cy: DCPE b ; R = Ph: DPPE c ) to form the diphosphene complexes (DRPE)Ni[η²-(PSiMe₃)₂] 5a–c . Using low temperature nmr measurements the monosubstitution products (DRPE)Ni[P(SiMe₃)₂]Cl 2a–c and the disubstitution products (DRPE)Ni[P(SiMe₃)₂]₂ 3a, 3c can be detected as intermediates. From the reaction of 1b the paramagnetic nickel(I) complex (DCPE)NiP(SiMe₃)₂ 4b can be isolated. Reacting 1a, 1b with LiP(SiMe₃)CMe₃ the complexes (DRPE)Ni[P(SiMe₃)CMe₃]Cl 8a, 8b , which are analogous to 2 , and the nickel(0) diphosphine complex (DEPE)Ni[η¹-P(SiMe₃)CMe₃P(SiMe₃)CMe₃] 9a can be detected n.m.r. spectroscopically, but no diphosphene complexes can finally be isolated. The diphosphene complexes (DRPE)Ni[η²(PPh)₂] 10a-c are available from reactions of PhP(SiMe₃)₂with l a - c. MeP(SiMe,), reacts only with 1b to give a diphosphene complex (DCPE)Ni[η²(PMe)₂] 11 b. Reacting [P(SiMe₃)CMe₃]₂ with 1a-c the diphosphene complexes (DRPE)Ni[η²(PCMe₃)₂] 12a-c can be obtained. 4b crystallizes monoclinic in the space group P2Jc with a = 1228.6 pm, b = 2387.1 pm, c = 2621.8 pm, β = 92.16°, and Z = 8 formula units. The nickel atom is nearly planar coordinated by three phosphorus- atoms, the phosphorus atom of the terminal P(SiMe₃)₂ group is pyramidally coordinated. The Ni? P bond distances of the two four-coordinated phosphorus atoms are with 219.2 pm and 220.2 pm only slightly shorter than the corresponding distance of the P-atom of the P(SiMe₃)₂ group with 223.5 pm. N.m.r. and mass spectral data are reported.     

Silicon‐ and Tin‐Containing Open‐Chain and Eight‐Membered‐Ring Compounds as Bicentric Lewis Acids toward Anions

Herein, we report the syntheses of silicon‐ and tin‐containing open‐chain and eight‐membered‐ring compounds Me₂Si(CH₂SnMe₂X)₂ ( 2 , X=Me; 3 , X=Cl; 4 , X=F), CH₂(SnMe₂CH₂I)₂ ( 7 ), CH₂(SnMe₂CH₂Cl)₂ ( 8 ), cyclo‐Me₂Sn(CH₂SnMe₂CH₂)₂SiMe₂ ( 6 ), cyclo‐(Me₂SnCH₂)₄ ( 9 ), cyclo‐Me_(2?n)X_nSn(CH₂SiMe₂CH₂)₂SnX_nMe_(2?n) ( 5 , n=0; 10 , n = 1, X= Cl; 11 , n=1, X= F; 12 , n=2, X= Cl), and the chloride and fluoride complexes NEt₄[cyclo‐ Me(Cl)Sn(CH₂SiMe₂CH₂)₂Sn(Cl)Me?F] ( 13 ), PPh₄[cyclo‐Me(Cl)Sn(CH₂SiMe₂CH₂)₂Sn(Cl)Me?Cl] ( 14 ), NEt₄[cyclo‐Me(F)Sn(CH₂SiMe₂CH₂)₂Sn(F)Me?F] ( 15 ), [NEt₄]₂[cyclo‐Cl₂Sn(CH₂SiMe₂CH₂)₂SnCl₂?2 Cl] ( 16 ), M[Me₂Si(CH₂Sn(Cl)Me₂)₂?Cl] ( 17 a , M=PPh₄; 17 b , M=NEt₄), NEt₄[Me₂Si(CH₂Sn(Cl)Me₂)₂?F] ( 18 ), NEt₄[Me₂Si(CH₂Sn(F)Me₂)₂?F] ( 19 ), and PPh₄[Me₂Si(CH₂Sn(Cl)Me₂)₂?Br] ( 20 ). The compounds were characterised by electrospray mass‐spectrometric, IR and ¹H, ¹³C, ¹⁹F, ²⁹Si, and ¹¹⁹Sn NMR spectroscopic analysis, and, except for 15 and 18 , single‐crystal X‐ray diffraction studies.     

Pyrene-Terminated Tin Sulfide Clusters: Optical Properties and Deposition on a Metal Surface

Herein, we present the synthesis of two pyrene-functionalized clusters, [(R^pyrSn)₄S₆]⋅2 CH₂Cl₂ ( 4 ) and [(R^pyrSn)₄Sn₂S₁₀]⋅n CH₂Cl₂ (n=4, 5 a ; n=2, 5 b ; R^pyr=CMe₂CH₂C(Me)N-NC(H)C₁₆H₉), both of which form in reactions of the organotin sulfide cluster [(R^NSn)₄S₆] ( C ; R^N=CMe₂CH₂C(Me)N-NH₂) with the well-known fluorescent dye 1-pyrenecarboxaldehyde ( B ). In contrast, reactions using an organotin sulfide cluster with another core structure, [(R^NSn)₃S₄Cl] ( A ), leads to formation of small molecular fragments, [(R^pyrCl₂Sn)₂S] ( 1 ), (pyren-1-ylmethylene)hydrazine ( 2 ), and 1,2-bis(pyren-1-ylmethylene)hydrazine ( 3 ). Besides synthesis and structures of the new compounds, we report the influence of the inorganic core on the optical properties of the dye, which was analyzed exemplarily for compound 5 a via absorption and fluorescence spectroscopy. This cluster was also used for exploring the potential of such non-volatile clusters for deposition on a metal surface under vacuum conditions.     

Synthese,NMR‐Spektren und Molekülstruktur von [(CH3)2Ga{μ‐P(H)Si(CH3)3}2Ga(CH3)2{μ‐P(Si(CH3)3)2}Ga(CH3)2]

Synthesis, NMR Spectra and Structure of [(CH₃)₂Ga{μ‐P(H)Si(CH₃)₃}₂Ga(CH₃)₂{μ‐P(Si(CH₃)₃)₂}Ga(CH₃)₂] The title compound has been prepared in good yield by the reaction of [Me₂GaOMe]₃ (Me = CH₃) with HP(SiMe₃)₂ in toluene (ratio 1 : 1,1) and purified by crystallization from pentane or toluene, respectively. This organogallium compound forms (Ga–P)₃ ring skeletons with one Ga–P(SiMe₃)₂–Ga and two Ga–P(H)SiMe₃–Ga bridges and crystallizes in the monoclinic space group C2/c. The known homologous Al‐compound is isotypic, both (M^III–P)₃ heterocycles have twist‐conformations, the ligands of the monophosphane bridges have trans arrangements.     

Are Organotin Reagents Derived from Bis(trimethylsilyl)picoline Suitable Precursors for the Preparation of Cyclometallated Complexes?

The organotin reagents [2‐PyC(SiMe₃)₂SnR₃] (R = Me, ⁿBu) were prepared in good yields from the reaction between the lithium salt of 2‐bis(trimethylsilyl)picoline and the corresponding trialkyltin chlorides. Reactions of these organotin reagents were carried out with various Pd and Pt complexes including [MCl₂(cod)] and [MCl₂(PhCN)₂] (M = Pd, Pt). The results show that a Me group is transferred to the metal atom, rather than the 2‐bis(trimethylsilyl)picolyl group. The mechanism for this reaction is discussed and reasons why Me group transfer occurs based on DFT computed structural data are given.     

Bis(arylimido) Molybdenum(VI) Amidinate and Guanidinate Complexes; Molecular Structures of [(ArN)2MoMe{N(Cy)C[N(i‐Pr)2]N(Cy)}] (Ar = 2,6‐i‐Pr2C6H3; Cy = Cyclohexyl) and [(2,6‐i‐Pr2C6H3N)2MoCl2] · [NH=C(C6H5)CH(SiMe3)2]

The reaction of [(ArN)₂MoCl₂] · DME (Ar = 2,6‐i‐Pr₂C₆H₃) ( 1 ) with lithium amidinates or guanidinates resulted in molybdenum(VI) complexes [(ArN)₂MoCl{N(R¹)C(R²)N(R¹)}] (R¹ = Cy (cyclohexyl), R² = Me ( 2 ); R¹ = Cy, R² = N(i‐Pr)₂ ( 3 ); R¹ = Cy, R² = N(SiMe₃)₂ ( 4 ); R¹ = SiMe₃, R² = C₆H₅ ( 5 )) with five coordinated molybdenum atoms. Methylation of these compounds was exemplified by the reactions of 2 and 3 with MeLi affording the corresponding methylates [(ArN)₂MoMe{N(R¹)C(R²)N(R¹)}] (R¹ = Cy, R² = Me ( 6 ); R¹ = Cy, R² = N(i‐Pr)₂ ( 7 )). The analogous reaction of 1 with bulky [N(SiMe₃)C(C₆H₅)C(SiMe₃)₂]Li · THF did not give the corresponding metathesis product, but a Schiff base adduct [(ArN)₂MoCl₂] · [NH=C(C₆H₅)CH(SiMe₃)₂] ( 8 ) in low yield. The molecular structures of 7 and 8 are established by the X‐ray single crystal structural analysis.     

Silyl‐Phosphino‐Carbene Complexes of Uranium(IV)

Unprecedented silyl‐phosphino‐carbene complexes of uranium(IV) are presented, where before all covalent actinide–carbon double bonds were stabilised by phosphorus(V) substituents or restricted to matrix isolation experiments. Conversion of [U(BIPM^TMS)(Cl)(μ‐Cl)₂Li(THF)₂] ( 1 , BIPM^TMS=C(PPh₂NSiMe₃)₂) into [U(BIPM^TMS)(Cl){CH(Ph)(SiMe₃)}] ( 2 ), and addition of [Li{CH(SiMe₃)(PPh₂)}(THF)]/Me₂NCH₂CH₂NMe₂ (TMEDA) gave [U{C(SiMe₃)(PPh₂)}(BIPM^TMS)(μ‐Cl)Li(TMEDA)(μ‐TMEDA)_0.5]₂ ( 3 ) by α‐hydrogen abstraction. Addition of 2,2,2‐cryptand or two equivalents of 4‐N,N‐dimethylaminopyridine (DMAP) to 3 gave [U{C(SiMe₃)(PPh₂)}(BIPM^TMS)(Cl)][Li(2,2,2‐cryptand)] ( 4 ) or [U{C(SiMe₃)(PPh₂)}(BIPM^TMS)(DMAP)₂] ( 5 ). The characterisation data for 3 – 5 suggest that whilst there is evidence for 3‐centre P?C?U π‐bonding character, the U=C double bond component is dominant in each case. These U=C bonds are the closest to a true uranium alkylidene yet outside of matrix isolation experiments.     

Dinuclear Dysprosium and Ytterbium Complexes Incorporating N,N‐Bis(pyrrolyl‐α‐methyl)‐N‐methylamine Ligand: Syntheses and Structures

Reaction of DyCl₃ with two equivalents of NaN(SiMe₃)₂ in THF yielded {Dy(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂ ( 1 ). X‐ray crystal structure analysis revealed that 1 is a centrosymmetric dimer with asymmetrically bridging chloride ligands. The metal coordination arrangement can be best described as distorted trigonal bipyramid. The bond lengths of Ln–Cl and Ln–N showed a decreasing trend with the contraction of the size of Ln³⁺. Treatment of N,N‐bis(pyrrolyl‐α‐methyl)‐N‐methylamine (H₂dpma) with 1 and known compound {Yb(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂, respectively, led to the formations of [Dy(μ‐Cl)(dpma)(THF)₂]₂ ( 2 ) and {Yb(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂ ( 3 ). Compounds 2 and 3 were fully characterized by single‐crystal X‐ray crystallography, elemental analysis, and ¹H NMR spectroscopy. Structure determination indicated that 2 and 3 exhibit as centrosymmetric dimers with asymmetrically bridging chloride ligands. One pot reactions involving LnCl₃ (Ln = Dy and Yb), LiN(SiMe₃)₂, and H₂dpma were explored and desired products 2 and 3 were not yielded, which indicated that 1 and {Yb(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂ are the demanding precursors to synthesize Dysprosium and Ytterbium complexes supported by dpma^2– ligand. Compounds 2 and 3 are the first reported lanthanide complexes chelated by dpma^2– ligand.     

Reaction of Hexafluoroacetone with Aminophosphites Containing the 2,2,2-Trifluoro-1-(trifluoromethyl)ethyl Grouping

Abstract

The reactions of dihaloaminophosphines RNHPF₂, (R=H, Me, tBu) and R₂NPCl₂ (R?Me, Et, SiMe₃; R₂?CH₂(CH₂CMe₂)₂ with LiOCH(CF₃)₂ yield the corresponding aminophosphites R₂NP[OCH(CF₃)₂)_2. Hexafluoroacetone reacts with RNH[OCH(CF₃)₂]₂ as well as MeNHPF₂ and tBuNHPF₂ in good yields to the 1,3,5λ⁵-oxazaphosphetanes 1-4, which show rapid pseudorotation at room temperature.     

Metallkomplexe mit biologisch wichtigen Liganden. CLVII [1] Halbsandwich‐Komplexe mit Isocyanoacetylaminosäureestern und Isocyanoacetyldi‐ und tripeptidestern („Isocyano‐Peptide”︁)

Metal Complexes of Biologically Important Ligands, CLVII [1] Halfsandwich Complexes of Isocyanoacetylamino acid esters and of Isocyanoacetyldi‐ and tripeptide esters (?Isocyanopeptides”?) N‐Isocyanoacetyl‐amino acid esters CNCH₂C(O) NHCH(R)CO₂CH₃ (R = CH₃, CH(CH₃)₂, CH₂CH(CH₃)₂, CH₂C₆H₅) and N‐isocyanoacetyl‐di‐ and tripeptide esters CNCH₂C(O)NHCH(R¹)C(O)NHCH(R²)CO₂C₂H₅ and CNCH₂C(O)NHCH(R¹)C(O)NHCH (R²)C(O)NHCH(R³)CO₂CH₃ (R¹ = R² = R³ = CH₂C₆H₅, R² = H, CH₂C₆H₅) are available by condensation of potassium isocyanoacetate with amino acid esters or peptide esters. These isocyanides form with chloro‐bridged complexes [(arene)M(Cl)(μ‐Cl)]₂ (arene = Cp*, p‐cymene, M = Ir, Rh, Ru) in the presence of Ag[BF₄] or Ag[CF₃SO₃] the cationic halfsandwich complexes [(arene)M(isocyanide)₃]⁺X^? (X = BF₄, CF₃SO₃).