Synthesis and Crystal Structures of Novel Copper(I) Clusters with Bridging Silyl Amide Ligands

Treatment of copper(I) chloride with R₂Si(NLiPh)₂ (R = Me, Ph) in thf led to the formation of the octanuclear cluster compounds [Cu₈{(R₂Si(NPh)₂}₄] [R = Me ( 1 ), Ph ( 2 ).] Compound 1 crystallizes in the tetragonal space group P4/n, with a = 1505.41(5) and c = 1911.32(7) pm. The X‐ray crystal structure determination revealed a cube shaped Cu₈ cluster core with μ₄ bridging Me₂Si(NPh)₂^2– ligands. The copper atoms display an almost linear coordination with Cu–N distances in the range of 191.1(3)–191.4(3) pm. The Cu–Cu distances are 265.7(1)–267.3(1) pm. Compound 2 forms monoclinic crystals, space group P2₁/n, with a = 1461.87(4), b = 2483.77(6), c = 2725.49(8) pm, β = 100.77(1)°. The cluster core of compound 2 consists formally of two mutually perpendicular arranged trigonal prisms, which share a common square face. Like in the case of compound 1 the square faces of the cluster core are capped by μ₄ bridging Ph₂Si(NPh)₂^2– ligands. The copper atoms adopt a nearly linear N–Cu–N coordination with Cu–N distances of 190.0(4)–195.1(4) pm. The Cu–Cu distances are 252.3(1)–305.6(1) pm.     

Synthesis,Crystal Structure,and Spectroscopic Characterization of the Borazine Derivatives [B{CH2(SiCl3)}NH]3 and [B{CH2(SiCl2CH3)}NH]3

The borazine derivatives B, B′, B″‐tris[(trichlorosilyl)methyl]borazine [B{CH₂(SiCl₃)}NH]₃ ( 1 ), and B, B′, B″‐tris[{dichloro(methyl)silyl}methyl]borazine [B{CH₂(SiCl₂CH₃)}NH]₃ ( 2 ) were prepared by reacting (Cl₃Si)CH₂(BCl₂) ( 3 ) and [Cl₂(CH₃)Si]CH₂(BCl₂) ( 4 ) with hexamethyldisilazane (hmds), respectively. Both compounds, 1 and 2 crystallize in space group R3c with a = 1712.53(4), c = 1230.33(4) pm, Z = 6, R₁ = 0.030, and a = 1713.8(2), c = 1258.7(2) pm, Z = 6, R₁ = 0.034, respectively. According to the single crystal X‐ray diffraction analyses, the title compounds show a planar B₃N₃ six‐membered ring with B—N distances of 142.3(3) pm (point symmetry C₃) and synfacial oriented substituents. The borazine derivatives have also been characterized by NMR and IR spectroscopy as well as by MS spectrometry.     

Hydroalumination and Hydrogallation Reactions with Tri(ethynyl)silanes – Generation of Compounds with up to Three Coordinatively Unsaturated Aluminium Atoms

Hydroalumination or hydrogallation of tri(ethynyl)silanes, RSi(C≡C‐Ar)₃ ( 1a , R = Ph, Ar = Ph; 1b , R = Me, Ar = Ph; 1c , R = Me, Ar = C₆H₄Me), with the element hydrides H‐EtBu₂ (E = Al, Ga) in stoichiometric ratios of 1:1 to 1:3 at ambient temperature yielded the addition products (PhC≡C)₂(R)Si[(tBu₂E)C=C(H)Ph] ( 2 , R = Ph, E = Ga; 3a , R = Me, E = Al; 3b , R = Me, E = Ga), (PhC≡C)(Me)Si[(tBu₂E)C=C(H)Ph]₂ ( 4a , E = Al, 4b , E = Ga) and (Me)Si[(tBu₂Al)C=C(H)Ar]₃ ( 5 , Ar = Ph; 6 , Ar = C₆H₄Me). Compounds 2 – 4 show a relatively close interaction between the coordinatively unsaturated aluminium or gallium atoms and one of the C_α(≡C) atoms of unreacted alkyne substituents [245 (E = Al) and 266 pm (E = Ga)] that stabilises the kinetically favoured cis addition products with E and hydrogen on the same side of the resulting C=C double bonds. In the absence of these stabilising effects the compounds were found to isomerise to the thermodynamically favoured trans isomers.     

Synthesis and Crystal Structure of a Tetranuclear Molybdenum(II) Silylamido Cluster

Treatment of molybdenum(II) chloride with the difunctional silylamide Li₂Me₂Si(NPh)₂ led to the formation of the tetranuclear cluster compound [Mo₄{Me₂Si(NPh)₂}₄]. According to the X-ray crystal structure determination, the central core of the cluster consists of four molybdenum atoms in a nearly rectangular arrangement. There are two μ₄-κ-N,N,N',N'-Me₂Si(NPh)₂^2– ligands capping the Mo₄ rectangle and two μ₂-Me₂Si(NPh)₂^2– ligands located at opposite edges. The alternating Mo–Mo distances of 218.1(1) and 279.5(1) pm indicate the presence of a cyclobutadiyne type cluster with alternating Mo–Mo triple and single bonds.     

Röntgenstrukturuntersuchungen an den polymorphen Elpasolithen K2LiAlF6 und Rb2LiGaF6

X-Ray Structural Studies of the Polymorphic Elpasolites K₂LiAlF₆ and Rb₂LiGaF₆ At single crystals of low (LT) and high temperature (HT) modifications of K₂LiAlF₆ and of Rb₂LiGaF₆, synthesized at normal pressure (NP), the crystal structures were refined. LT-K₂LiAlF₆ is a cubic elpasolite (Fm3m, Z = 4, a = 784.2(1) pm; Al–F: 181.2(1) pm), HT-K₂LiAlF₆ and NP-Rb₂LiGaF₆ are isostructural with the hexagonal-rhombohedral type of Cs₂NaCrF₆ (R3m, Z = 6, a = 561.7(1) resp. 586.3(1), c = 2757.6(6) resp. 2856.3(5) pm; mean values Al–F: 180.5 resp. Ga–F: 189.3 pm). A cubic high pressure modification (HP) of Rb₂LiGaF₆ was obtainable as a powder only (a = 820.8(2) pm). The relations of distances between LT/HT and HP/NP polymorphs of elpasolites are compared and discussed.     

Bifunktionalisierte 1 H‐Phosphiren‐ und g1‐1‐Phosphaallen‐Wolframkomplexe

Bifunctionalized 1 H‐Phosphirene and g¹‐1‐Phosphaallene Tungsten Complexes The tungsten(0) complex [{(Me₃Si)₂HCPC(Ph)=N}W(CO)₅] 1 reacts upon heating with acetylene derivatives 2 a–d in toluene to form benzonitrile and the complexes [{(Me₃Si)₂HCPC(R)=COEt} · W(CO)₅] 5 a–d ( 5 a : R = SiMe₃; 5 b : R = SiPh₃; 5 c : R = SnMe₃; 5 d : R = SnPh₃) and [{(Me₃Si)₂HCP=C=C(OEt)R} · W(CO)₅] 6 a, b ( 6 a : R = SnMe₃; 6 b : R = SnPh₃), which have been isolated by chromatography; complexes 5 c and 6 a have been characterized as mixtures. Spectroscopic and mass spectrometric data are discussed. The crystal structure of the compound 5 a was determined by X‐ray single crystal structure analysis ( 5 a : space group P2₁/n, Z = 4, a = 977.6(2) pm, b = 1814.6(4) pm, c = 1628.0(4) pm, β = 93.95(2)°).     

Two‐ and Three‐Dimensional [IrSi] Networks in the Silicides Sm3Ir2Si2, HoIrSi,and YbIrSi

New intermetallic rare earth iridium silicides Sm₃Ir₂Si₂, HoIrSi, and YbIrSi were synthesized by reaction of the elements in sealed tantalum tubes in a high‐frequency furnace. The compounds were investigated by X‐ray diffraction both on powders and single crystals. HoIrSi and YbIrSi crystallize in a TiNiSi type structure, space group Pnma: a = 677.1(1), b = 417.37(6), c = 745.1(1) pm, wR2 = 0.0930, 340 F² values for HoIrSi, and a = 667.2(2), b = 414.16(8), c = 742.8(2) pm, wR2 = 0.0370, 262 F² values for YbIrSi with 20 parameters for each refinement. The iridium and silicon atoms build a three‐dimensional [IrSi] network in which the holmium(ytterbium) atoms are located in distorted hexagonal channels. Short Ir–Si distances (246–256 pm in YbIrSi) are indicative for strong Ir–Si bonding. Sm₃Ir₂Si₂ crystallizes in a site occupancy variant of the W₃CoB₃ type: Cmcm, a = 409.69(2), b = 1059.32(7), c = 1327.53(8) pm, wR2 = 0.0995, 383 F² values and 27 variables. The Ir1, Ir2, and Si atoms occupy the Co, B2, and B1 positions of W₃CoB₃, leading to eight‐membered Ir₄Si₄ rings within the puckered two‐dimensional [IrSi] network. The Ir–Si distances range from 245 to 251 pm. The [IrSi] networks are separated by the samarium atoms. Chemical bonding in HoIrSi, YbIrSi, and Sm₃Ir₂Si₂ is briefly discussed.     

Ternary Rhodium Borides A3Rh5B2 (A = Mg,Sc) and Quaternary Derivatives A2MRh5B2. Preparation,Crystal Structure (M = Main Group and 3 d Elements), and Magnetism (M = Mn,Fe)

The new ternary rhodium borides Mg₃Rh₅B₂ and Sc₃Rh₅B₂ (P4/mbm, Z = 2; a = 943.4(1) pm, c = 292.2(1) pm and a = 943.2(1) pm, c = 308.7(1) pm, respectively) crystallize with the Ti₃Co₅B₂ type structure. Mg and Sc may in part be substituted by a variety of elements M. For M = Si and Fe, homogeneity ranges were found according to A_3–xM_xRh₅B₂ with 0 ≤ x ≤ 1.0 for A = Sc and with x up to 1.5 for A = Mg. Quaternary compounds with x = 1 (A₂MRh₅B₂: A/M in short) were prepared with M = Be, Al, Si, P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Sn (Co, Ni only with A = Mg; Sn only with A = Sc; P, As with deficiencies). Single crystal X‐ray investigations show an ordered substitutional variant of the Ti₃Co₅B₂ type in which the M atoms are arranged in chains along [001] with intrachain and interchain M–M distances of about 300 pm and 660 pm, respectively. Measuring the magnetisation (1.7 K–800 K) of the phases Mg/Mn, Sc/Mn, Mg/Fe, and Sc/Fe reveals antiferromagnetic interactions in the first and dominating ferromagnetic intrachain interactions in the remaining ones. Interchain interactions of antiferromagnetic nature are evident in Sc/Mn and Mg/Fe leading to metamagnetism below T_N = 130 K, while Sc/Fe behaves ferromagnetically below T_C = 450 K. The overall trend towards stronger ferromagnetic interactions with increasing valence electron concentration is obvious.     

Schwache Sn…I‐Wechselwirkungen in den Kristallstrukturen der Iodostannate [SnI4]2– und [SnI3]–

Weak Sn…I Interactions in the Crystal Structures of the Iodostannates [SnI₄]^2– and [SnI₃]^– Iodostannate complexes can be crystallized from SnI₂ solutions in polar organic solvents by precipitation with large counterions. Thereby isolated anions as well as one, two or three‐dimensional polymeric anionic substructures are established, in which SnI₃^– and SnI₄^2– groups are linked by weak Sn…I interactions. Examples are the iodostannates [Me₃N–(CH₂)₂–NMe₃][SnI₄] ( 1 ), (Ph₄P)₂[Sn₂I₆] ( 2 ), [Me₃N–(CH₂)₂–NMe₃][Sn₂I₆] ( 3 ), [Fe(dmf)₆][SnI₃]₂ ( 4 ) and (Pr₄N)[SnI₃] ( 5 ), which have been characterized by single crystal X‐ray diffraction. [Me₃N–(CH₂)₂–NMe₃][SnI₄] ( 1 ): a = 671.6(2), b = 1373.3(4), c = 2046.6(9) pm, V = 1887.7(11) · 10⁶ pm³, space group Pbcm;(Ph₄P)₂[Sn₂I₆] ( 2 ): a = 1168.05(6), b = 717.06(4), c = 3093.40(10) pm, β = 101.202(4)°, V = 2541.6(2) · 10⁶ pm³, space group P2₁/n;[Me₃N–(CH₂)₂–NMe₃][Sn₂I₆] ( 3 ): a = 695.58(4), b = 1748.30(8), c = 987.12(5) pm, β = 92.789(6)°, V = 1199.00(11) · 10⁶ pm³, space group P2₁/c;[Fe(dmf)₆][SnI₃]₂ ( 4 ): a = 884.99(8), b = 1019.04(8), c = 1218.20(8) pm, α = 92.715(7), β = 105.826(7), γ = 98.241(7), V = 1041.7(1) · 10⁶ pm³, space group P1;(Pr₄N)[SnI₃] ( 5 ): a = 912.6(2), b = 1205.1(2), c = 1885.4(3) pm, V = 2073.5(7) · 10⁶ pm³, space group P2₁2₁2₁.     

Synthese und Struktur von dreikernigen Heterometall-Komplexen mit Nitridobrücken zwischen Re und Sn

Synthesis and Structure of Threenuclear Heterometallic Complexes with Nitrido Bridges between Re and Sn The threenuclear heterometallic complex [(Me₂PhP)₂ClRe(μ-Cl)N]₂SnCl₄ results from the reaction of ReNCl₂(PMe₂Ph)₃ with SnCl₄ in CH₂Cl₂. The brown, air-sensitive complex is diamagnetic. It crystallizes with two solvate molecules as [(Me₂PhP)₂ClRe(μ-Cl)N]₂SnCl₄ · 2 CH₂Cl₂ in the space group P 1 with a = 1189.1(2), b = 1262.3(2), c = 1776.7(3) pm, α = 86.04(2), β = 89.27(2), γ = 72.75(1)°, Z = 2. In the threenuclear complex two fragments (Me₂PhP)₂ClReN, which are connected by two Cl bridges, coordinate with their nitrido ligands one SnCl₄ molecule. The two resulting nitrido bridges complete the coordination of the Sn atom to a distorted octahedron with a cis arrangement of the N atoms. The bent nitrido bridges (Re–N–Sn = 155) are asymmetrical with distances Re–N = 168 pm and Sn–N = 225 pm. An incomplete exclusion of water during the synthesis leads to the formation of [(Me₂PhP)₃ClRe(μ-Cl)N]Sn₂(OH)Cl₇ · 2 CH₂Cl₂ in form of air-stable, red-violett crystals (P 1, a = 1074.1(2), b = 1251.1(3), c = 1685.0(1) pm, α = 99.61(2), β = 91.49(2), γ = 92.69(2)°, Z = 2). In the diamagnetic complex one molecule ReNCl₂(PMe₂Ph)₃ is coordinated by the nitrido ligand and one Cl bridge to the Sn atoms of a unit Sn₂(OH)Cl₇. In this unit the two Sn atoms are connected by one Cl and one OH bridge. The distances in the almost linear nitrido bridge (Re–N–Sn = 164.6) are Re–N = 170.5 pm and Sn–N = 219.8 pm.     

Common Features in the Crystal Structures of the Compounds Bis(dimethylstibanyl)oxane and ‐sulfane,and the Minerals Valentinite and Stibnite (Grauspießglanz)

Bis(dimethylstibanyl)oxane ( 1 ) and ‐sulfane ( 2 ), the two simplest organoelement species with an Sb–E–Sb fragment (E = O, S), were prepared by alkaline hydrolysis of bromodimethylstibane and by oxidation of tetramethyldistibane with sulfur [18], respectively. As shown by an x‐ray structure analysis of compound 1 (m. p. < –20 °C; P2₁2₁2₁, a = 675.9(2), b = 803.1(2), c = 1666.8(4) pm at –70 ± 2 °C; Z = 4; R1 = 0.042), the molecules (O–Sb 198.8 and 209.9 pm, Sb–O–Sb 123.0°) adopt a syn‐anti conformation in the solid state and are arranged in zigzag chains along [010] via weak intermolecular O‥Sb interactions (258.5 pm, Sb–O‥Sb 117.8°, O‥Sb–O 173.5°) making use, however, of only one Me₂Sb moiety. Primary and secondary bond lengths and angles agree very well with corresponding values published for valentinite, the orthorhombic modification of antimony(III) oxide [3]. Bis(dimethylstibanyl)sulfane ( 2 ) (m. p. 29 to 31 °C) crystallizes in the uncommon space group P6₅22 (a = 927.8(3), c = 1940.9(7) pm at –100 ± 2 °C; Z = 6; R1 = 0.021). Owing to coordination numbers of (1 + 1) and (2 + 2) for both Me₂Sb groups and the sulfur atom, respectively, molecules with an approximate syn‐syn conformation (S–Sb 249.8 pm, Sb–S–Sb 92.35°) build up a three‐dimensional net of double helices which are linked together by Sb‥S contacts (316.4 pm). These parameters shed more light onto the rather complicated structure and bonding situation in stibnite (antimony(III) sulfide [4]). The molecular packing of compound 2 is compared with the structures of relevant inorganic solids, especially with that of β‐quartz [37].     

Rare Earth Ruthenium Gallides with the Ideal Composition Ln2Ru3Ga5 (Ln = La–Nd,Sm) crystallizing with U2Mn3Si5 (Sc2Fe3Si5) Type Structure

The rare earth ruthenium gallides Ln₂Ru₃Ga₅ (Ln = La, Ce, Pr, Nd, Sm) were prepared by arc‐melting of cold‐pressed pellets of the elemental components. They crystallize with a tetragonal structure (P4/mnc, Z = 4) first reported for U₂Mn₃Si₅. The crystal structures of the cerium and samarium compounds were refined from single‐crystal X‐ray data, resulting in significant deviations from the ideal compositions: Ce₂Ru_2.31(1)Ga_5.69(1), a = 1135.10(8) pm, c = 580.58(6) pm, R_F = 0.022 for 742 structure factors; Sm₂Ru_2.73(2)Ga_5.27(2), a = 1132.95(9) pm, c = 562.71(6) pm, R_F = 0.026 for 566 structure factors and 32 variable parameters each. The deviations from the ideal compositions 2:3:5 are discussed. A mixed Ru/Ga occupancy occurs only for one atomic site. The displacement parameters are relatively large for atoms with mixed occupancy within their coordination shell and small for atoms with no neighboring sites of mixed occupancy. Chemical bonding is analyzed on the basis of interatomic distances. Ln–Ga bonding is stronger than Ln–Ru bonding. Ru–Ga bonding is strong and Ru–Ru bonding is weak. The Ga–Ga interactions are of similar strength as in elemental gallium.     

Neue Hypersilanide der Erdmetalle Aluminium,Gallium und Indium

New Hypersilanides of the Earth Metals Aluminium, Gallium, and Indium The dialkylaluminiumchlorides R₂AlCl (with R = Me, Et; Me = CH₃, Et = C₂H₅) react with base‐free lithium‐tris(trimethylsilyl)silanide (Li–Hsi; Hsi = –Si(SiMe₃)₃), forming the pyrophoric dialkyl aluminiumhypersilanides R₂Al–Hsi. The methyl compound is dimeric in solid state (triclinic space group P1, Z = 1 dimer), as in Al₂Me₆ the association takes place by two Al–Me–Al bridges, forming a centrosymmetric molecule of approximately C_2h point‐symmetry. Contrary to this (Me₂GaCl)₂ and Li–Hsi form a mixture of (MeGa(Hsi)Cl)₂ and [Me₃Ga–Hsi]Li. The monochloride again is a centrosymmetric, chlorine‐bridged dimer (monoclinic space group P2₁/n, Z = 2 dimers). The extremely air sensitive gallate can be prepared from GaMe₃ and Li–Hsi (1 : 1 ratio), as well as the homologous [Me₃Ga–Hsi]Na and [Me₃Ga–Hsi]K from GaMe₃ and the corresponding alkalimetal hypersilanides. The 1 : 1 toluene‐solvat of the sodium salt crystallizes in the orthorhombic space group Pbca (Z = 8) with polymeric zig‐zag‐chains, in which the toluene‐capped Na‐ions act as GaMe…Na…Me₂Ga‐bridges between [Me₃Ga–Hsi]^– anions. The reaction of InCl₃ with Li–Hsi (1 : 3 ratio) mainly gives LiCl, metallic In and the “dihypersilyl” Hsi–Hsi. Ruby‐red (Hsi)₂In–In(Hsi)₂ could also be obtained in low yield and characterized by X‐ray structure elucidation (space group P2₁/c, Z = 4). The ¹H, ¹³C, ²⁹Si and ⁷Li NMR‐ and the vibrational spectra of the hypersilanides have been measured and discussed.     

Synthese und Molekülstruktur von [Al(SiMe3)3(DBU)] (DBU = 1,8-Diazabicyclo[5.4.0]undec-7-en)

Synthesis and Molecular Structure of [Al(SiMe₃)₃(DBU)] (DBU = 1,8-Diazabicyclo[5.4.0]undec-7-ene) [Al(SiMe₃)₃(OEt₂)] reacts with DBU (DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene) at 0 °C yielding [Al(SiMe₃)₃ · (DBU)] ( 1 ). 1 was characterised spectroscopically (¹H, ¹³C, ²⁹Si, ²⁷Al NMR, IR, MS) and by X-ray structure determination [monoclinic, C2/c, a = 33.053(2), b = 9.307(1), c = 20.810(1) Å, β = 124.07(2)°, V = 5302.4(5) ų, Z = 8, 218(2) K]. 1 does not react with [Cp₂ZrCl₂] even in boiling toluene.     

Organotin Dyes: Synthesis and Structural Characterization of Dibutyltin and Dimethyltin Complexes with 2, 2′‐Dihydroxyazobenzene

The preparation and structures of 2, 2′‐dihydroxyazobenzenato‐dibutyl‐tin [Bu₂SnL] and 2, 2′‐dihydroxyazobenzenato‐dimethyl‐tin [Me₂SnL] are described. The complexes were characterized by IR, NMR (¹H, ¹³C, ¹¹⁹Sn) and UV/VIS spectra. The crystal structures were determined by X‐ray diffraction on single crystals. [Bu₂SnL]: monoclinic, space group P2₁/c, cell constants at 208 K: a = 860.73(5), b = 973, 51(18), c = 2340.0(3) pm, β = 93.615(11)°; R₁ = 0.0546. [Me₂SnL]: orthorhombic, space group Pbcn, cell constants at 208 K: a = 1914.6(4), b = 1041.3(3), c = 1323.27(14) pm; R₁ = 0.0529.     

New Ga/N‐based Active Lewis Pairs,Trifunctional Ga–Ga Compounds,Reactions with Cyanamide and Dual Insertion of Isocyanate

Hydrogallation of Me₃Si–C≡C–NR'₂ with R₂Ga–H (R = tBu, CH₂tBu, iBu) yielded Ga/N‐based active Lewis pairs, R₂Ga–C(SiMe₃)=C(H)–NR'₂ ( 7 ). The Ga and N atoms adopt cis‐positions at the C=C bonds and show weak Ga–N interactions. tBu₂GaH and Me₃Si–C≡C–N(C₂H₄)₂NMe afforded under exposure of daylight the trifunctional digallium(II) compound [MeN(C₂H₄)₂N](H)C=C(SiMe₃)Ga(tBu)–Ga(tBu)C(SiMe₃)=C(H)[N(C₂H₄)₂NMe] ( 8 ), which results from elimination of isobutene and H₂ and Ga–Ga bond formation. 8 was selectively obtained from the ynamine and [tBu(H)Ga–Ga(H)tBu]₂[HGatBu₂]₂. 7a (R = tBu; NR'₂ = 2,6‐Me₂NC₅H₈) and H₈C₄N–C≡N afforded the adduct tBu₂Ga‐C(SiMe₃)=C(H)(2,6‐Me₂NC₅H₈) · N≡C–NC₄H₈ ( 11 ) with the nitrile bound to gallium. The analogous ALP with harder Al atoms yielded an adduct of the nitrile dimer or oligomers of the nitrile at room temperature. The reaction of 7a with Ph–N=C=O led to the insertion of two NCO groups into the Ga–C_vinyl bond to yield a GaOCNCN heterocycle with Ga bound to O and N atoms ( 12 ).     

Substitutionsreaktionen der Bis(trimethylelement)carbodiimide des Siliciums und Germaniums mit Metallchloriden und Dimethylmetallchloriden des Sb,Al, Ga und In

Substitution Reactions of Bis(trimethylelement)carbodiimides of Silicon and Germanium with Metal Chlorides and Dimethylmetalchlorides of Sb, Al, Ga, and In The reaction of Me₃Ge? N?C?N? GeMe₃ (Me?CH₃) with SbCl₅ in a 1 : 1 molar ratio forms dimeric Cl₄SbNCNGeMe₃ in high yields. The corresponding compounds (X₂MNCNSiMe₃)_2–3 (with X?Cl, Me and M = Al, Ga), formed by reactions of X₂MCl and Me₃SiNCNSiMe₃, are less stable and tend to condensations, eliminating Me₃SiX. The carbodiimide derivates (Me₂MNCNEMe₃)_2–3 (with E = Si, Ge) are also available in aprotic solvents from polymeric LiNCNEMe₃ and Me₂MCl (M = Al, Ga, In). According to the IR and Raman spectra the low associated substitution products consists of cyclic ring skeletons and asymmetric > N? C?N? EMe₃ units with cyanamide conformation.     

Synthese und Struktur von zwei- und dreikernigen Heterometallkomplexen mit Nitridobrücken zwischen Re und Mo

Synthesis and Structure of Two- and Threenuclear Heterometallic Complexes with Nitrido Bridges between Re and Mo The reaction of ReNCl₂(PMe₂Ph)₃ with MoCl₄(NCEt)₂ yields the heterometallic threenuclear complex [{(Me₂PhP)₃(EtCN)ClRe≡N–}₂MoCl₄][MoNCl₅]. The anion [MoNCl₅]^2– presumably results from a transfer of the nitrido ligand from the Re to the Mo atom. The air-sensitive compound is paramagnetic with μ_eff = 2.87 B. M. at room temperature. A reduction of the magnetic moment to 1.74 B.M at 20 K starts at 140 K. The complex crystallizes in the orthorhombic space group Pca2₁ with a = 2430(1), b = 1328(1), c = 2436.3(2) pm, Z = 4. With bond angles Re–N–Mo of 164° and 167° the nitrido bridges are almost linear. The distances Re–N of 169 and 170 pm can be interpreted with triple bonds. The Mo–N bond lengths of 210 and 211 pm correspond to single bonds. In the anion [MoNCl₅]^2– the distance Mo≡N is 167 pm. Hydrolysis of the threenuclear complex results in a cleavage of one of the nitrido bridges to yield (Me₂PhP)₃(EtCN)ClRe≡N–MoOCl₄. The compound is paramagnetic with μ_eff = 1.71 B.M. at room temperature. It crystallizes in the orthorhombic space group Pbca with a = 1718.5(4), b = 2037(1), c = 2041.1(7) pm, Z = 8. In the dinuclear complex the [MoOCl₄]^– unit is only weakly coordinated to the nitrido ligand with Mo–N = 246.5 pm, while the distance of the Re≡N bond of 168.1 pm is almost unchanged in comparison with a terminal bond. The bond angle Re≡N–Mo is 165.6°.     

Reducing Ga?H and Ga?C Bonds in Close Proximity to Oxidizing Peroxo Groups: Conflicting Properties in Single Molecules

Treatment of [Li(H₂Ga{CH(SiMe₃)₂}₂)] ? 2 OEt₂ ( 1? 2 OEt₂) with two equivalents of tert‐butyl hydrogen peroxide, H‐O‐O‐CMe₃, afforded the organogallium peroxide [({(Me₃Si)₂HC}₂Ga(OH)(OOCMe₃)Li)₂] ( 3 ), which possesses oxidizing peroxo groups in close proximity to reducing Ga? C bonds. The lithium atoms of the dimeric formula units are coordinated by both oxygen atoms of the peroxides and by two hydroxo groups. The cleavage of the Ga? C bond was not observed, even when an excess of H‐O‐O‐CMe₃ was applied. Instead, the adduct [{(Me₃Si)₂HC}₂Ga(OH)(OOCMe₃)₂Li₂(HOOCMe₃)] ( 4 ) was isolated, which has an intact H‐O‐O‐CMe₃ molecule terminally attached to lithium. A similar structural motif was found for the compound [(LiOOCMe₃)₂(HOOCMe₃)₂] ( 5 ). The trihydrido gallanate [Li(H₃Ga? {CH(SiMe₃)₂})] ? OEt₂ ( 2 ) yielded the unique peroxide [({(Me₃Si)₂HC}? Ga(H)(OOCMe₃)₂Li)₂] ( 6 ) under similar conditions that possesses Ga? C and even more reactive Ga? H bonds beside peroxo groups. It decomposed at room temperature by the insertion of oxygen atoms into the Ga? H bonds and the formation of [({(Me₃Si)₂HC}? Ga(OH)(OCMe₃)(OOCMe₃)Li)₂] ( 7 ), which was isolated in a low yield. Further decomposition gave the complete degradation of all peroxo groups with the formation of a relatively complicated Li₄Ga₄O₈ cage ( 8 ).     

Synthese und Kristallstruktur des Aminoimino‐Phosphinat–Kupfer(I)‐Komplexes [Cu(Me3SiNP(Ph)2NSiMe3)]2

Synthesis and Crystal Structure of the Aminoiminophosphinate Copper(I) Complex [Cu(Me₃SiNP(Ph)₂NSiMe₃)]₂ The title compound 1 was prepared by the reaction of Me₃SiNP(Ph)₂N(SiMe₃)₂ with copper(I) chloride at 120 °C to give colourless crystals which were characterized by a crystal structure determination. Space group C2/c, Z = 4, lattice dimensions at 193 K: a = 1854.0(3), b = 1256.2(3), c = 1969.9(3) pm, β = 106.30(2)°; R₁ = 0.063. 1 forms dimeric molecules with a nonplanar Cu₂N₄P₂ eight‐membered ring of symmetry C₂ and a rather long Cu…Cu distance of 262.1(1) pm.