Nitrido Bridge Research Articles

Kurt Dehnicke 22.04.1931 – 16.01.2011

Kurt Dehnicke 22.04.1931 – 16.01.2011

Redox non-innocence of a nitrido bridge in a methane-activating dimer of iron phthalocyanine

A nitrido-bridged iron phthalocyanine has recently been shown to catalyze hydrocarbon activation, displaying in this respect distinctly different reactivity than the monomeric phthalocyanine or the oxo-bridged dimer. Here, DFT calculations are shown on models of this catalyst, indicating a distinct difference in electronic structures between the μ-oxo and μ-nitrido-bridged dimers, with the nitride acting as a remarkable charge reservoir and acquiring S = 1 N-character while the oxo bridge remains redox-inert; this difference in charge localization appears to be mirrored by a tendency towards higher symmetry in the Fe–N/O bonds with the nitrido bridge compared to the oxo one, and by a tendency of the nitride to favour lower-spin states more efficiently than the oxide.

Synthese und Kristallstruktur der Rhenium(VII)‐Nitridchloride ReNCl4 und ReNCl4·H2O

AbstractSyntheses and Crystal Structures of the Rhenium(VII) Nitride Chlorides ReNCl4 and ReNCl4·H2ORhenium(VII) nitride chloride, ReNCl4 (1) is obtained in form of brown needles with metallic luster by the reaction of ReCl5 with Cl3VNCl at 140 °C under vacuum in a sealed glass ampoule. It crystallizes in the tetragonal space group I4 with the lattice parameters a = 826.7(4), c = 405.1(2) pm, and Z = 2. The square pyramidal molecules are connected by asymmetric nitrido bridges to form chains along the crystallographic c axis. The shorter Re‐N distance of 163.0(5) pm corresponds to a triple bond, while the pronounced longer distance of 242.0(5) pm can be interpreted with a weak donor bond.The reaction of ReCl5 with VN at 170 °C under vacuum in a sealed glass ampoule yields red needles of ReNCl4·H2O (2). It crystallizes in the orthorhombic space group Pnma with a = 1075.4(2), b = 1108.5(2), c = 547.7(5) pm and Z = 4. The Re atoms exhibit a distorted octahedral coordination with the aqua ligand in trans position to the nitrido ligand. The Re‐N triple bond has a bond distance of 166.1(11) pm. The complexes are connected by hydrogen bridges O‐H···N to form chains.

Zwei Nitridchloride des Wolframs: W2NCl8 und W2NCl9

AbstractTwo Tungsten Nitride Chlorides: W2NCl8 and W2NCl9A solid state reaction of tungsten(VI)chloride and cyanamide yielded black crystals of W2NCl8 and red plate‐like crystals of W2NCl9. The structures of these compounds were determined by single crystal X‐ray diffraction. The crystal structure of W2NCl8 contains [Cl2/2Cl3WNWCl3Cl2/2]‐units forming chains along the c‐axis. The tungsten atoms are linked by a symmetric nitrido bridge (d(W–N) = 1.8203(4) Å). The crystal structure of W2NCl9 contains a dichloro‐bridged dimer of a nitride‐bridged ditungsten unit [Cl5WNWCl3Cl2/2]2 with two different W–N distances of 1.726(9) Å and 2.012(9) Å.

Synthese, Struktur und Eigenschaften der Komplexe [(H2O)Cl4Os≡N‐IrCl(C5Me5)(AsPh3)], [(Ph3Sb)Cl4Os≡N‐IrCl(C5Me5)(SbPh3)], [(Ph3Sb)2Cl3Os≡N‐IrCl(COD)] und [{(Me2PhP)2(CO)Cl2Re≡N}2ReNCl2(PMe2Ph)

AbstractSynthesis, Crystal Structure, and Properties of the Complexes [(H2O)Cl4Os≡N‐IrCl(C5Me5)(AsPh3)], [(Ph3Sb)Cl4Os≡N‐IrCl(C5Me5)(SbPh3)], [(Ph3Sb)2Cl3Os≡N‐IrCl(COD)] and [{(Me2PhP)2(CO)Cl2Re≡N}2ReNCl2(PMe2Ph)]The dinuclear complexes [(H2O)Cl4Os≡N‐IrCl(C5Me5)(AsPh3)]·H2O (1·H2O), [(Ph3Sb)Cl4Os≡N‐IrCl(C5Me5)(SbPh3)] (2), and [(Ph3Sb)2Cl3Os≡N‐IrCl(COD)] (3) result from the reaction of the nitrido complexes [(Ph3As)2OsNCl3] and [(Ph3Sb)2OsNCl3] with the iridium compounds [IrCl2(C5Me5)]2 and [IrCl(COD)]2 in dichloromethane. 1 crystallizes as 1·H2O in form of green platelets in the monoclinic space group Cm and a = 1105.53(6); b = 1486.76(9); c = 2024.88(10) pm, β = 97.191(4)°, Z = 4. The formation of 1 in air involves a ligand exchange, and the coordination of a water molecule in trans position to the Os‐N triple bond. The resulting complex fragments [(H2O)Cl4Os≡N] and [IrCl(C5Me5)(AsPh3)] are connected by an asymmetric nitrido bridge Os≡N‐Ir. The nitrido bridge is characterised by an Os‐N‐Ir bond angle of 173.7(7)°, and distances Os‐N = 168(1) pm and Ir‐N = 191(1) pm. 2 crystallizes in clumped together brown platelets with the space group ${\rm P}{\bar 1}$ and a = 1023.3(3), b = 1476.2(3), c = 1872.5(6) pm, α = 74.60(2), β = 73.84(2), γ = 76.19(2)°, Z = 2. In 2 the asymmetric nitrido bridge Os≡N‐Ir joins the two complex fragments [(Ph3Sb)Cl4Os≡N] and [IrCl(C5Me5)(SbPh3)], which are formed by a ligand exchange reaction. 3 forms dark green crystals with the triclinic space group ${\rm P}{\bar 1}$ and a = 1079.4(1), b = 1172.3(1), c = 1696.7(2) pm, α = 101.192(9),β = 92.70(1), γ = 92.61(1)°, Z = 2. The distances in the almost linear nitrido bridge (Os≡N‐Ir = 175.3(7)°) are Os‐N = 171(1) pm and Ir‐N = 183(1) pm. The reaction of [ReNCl2(PMe2Ph)3] with [Mo(CO)3(NCMe)3] unexpectedly affords the trinuclear complex [{(Me2PhP)2(OC)Cl2Re≡N}2ReNCl2(PMe2Ph)] (4) as the main product. It forms triclinic brown crystals with the composition 4·2THF and the space group ${\rm P}{\bar 1}$ (a = 1382.70(7), b = 1498.58(7), c = 1760.4(1) pm, α = 99.780(7), β = 99.920(7), γ = 114.064(6)°, Z = 2). In the trinuclear complex, the central fragment, [ReNCl2(PMe2Ph)] is joined in trans position to two nitrido complexes [(Me2PhP)2(CO)Cl2Re≡N], giving an almost linear Re≡N‐Re‐N≡Re arrangement. The bond angles and distances in the nitrido bridges are Re‐N‐Re = 167.8(3)°, Re‐N = 171.1(8) pm and 204.2(8) pm; and Re‐N‐Re = 168.1(4)°, Re‐N = 170.9(9) and 203.5(9) pm respectively. As expected, the Re‐N bond length to the terminal nitrido ligand on the central Re atom is much shorter at 161.2(9) pm than the triple bonds of the asymmetric bridges.

Reactions of Nitridotechnetium(V) Complexes with Boranes

AbstractNitrido bridges between technetium and boron were formed during reactions of [TcN(PMe2Ph)(Et2dtc)2] (Et2dtc− = diethyldithiocarbamate) and BH3 or BPhCl2 at low temperatures. X‐Ray structure determinations show that the products contain almost linear Tc–N–B bonds with Tc–N distances which are only slightly lengthened with respect to the triple bonds in the precursor molecule. However, a significant lengthening of the Tc–S bond trans to the nitrido ligand is detected by the decrease of the structural trans influence of “N3−”N. The compounds are instable and decompose at room temperature under cleavage of the N–B bonds.A reaction between [TcNCl2(PPh3)2] and BCl3 does not yield a product with a nitrido bridge. Prolonged heating in dichloromethane results in decomposition of the technetium complex and the formation of (HPPh3)2[TcCl6]. Hydrogen bonds are established between the complex anion and each two counter ions.

Synthesis, Molecular Structure and Reactivity of a Calix[4]arene Monomethyl Ether Supported Nitridomolybdenum Complex

AbstractThe calix[4]arene monomethyl ether supported nitridomolybdenum complex [MoN(MeCalix)] (1) was obtained in high yield from the reaction of [MoN(OtBu)3] and calix[4]arene methyl ether (H3MeCalix). Contrary to the calix[4]arene dimethyl ether supported dioxomolybdenum complex [MoO2(paco‐Me2Calix)] published earlier, the calix[4]arene ligand in 1 adopts a cone conformation. Complex 1 reacts smoothly with GaCl3 and GaEt3 to yield the compounds [Mo(NGaCl3)(MeCalix)] (2) and [Mo(NGaEt3)(MeCalix)] (3), respectively. Complex 2 is the first structurally characterized example of a nitrido‐bridged dinuclear compound of a group 6 metal and a group 13 halide (EX3). The [Mo≡N–GaCl3] unit, in which both metal atoms are unsymmetrically bridged with a short Mo≡N and a long Ga–N contact, shows significant bending at the nitrido bridge. This deviation from a linear alignment is attributed to packing forces. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Synthese und Kristallstruktur von heteronuklearen Metallkomplexen mit Nitridobrücken Re≡N‐Ni, Re≡N‐Pt, Os≡N‐Rh und Os≡N‐Ir

AbstractSynthesis and Crystal Structure of Heteronuclear Metal Complexes with Nitrido Bridges Re≡N‐Ni, Re≡N‐Pt, Os≡N‐Rh, and Os≡N‐IrThe heteronuclear complex [(Me2PhP)3Br2Re≡N‐NiBr2(OPMe2Ph)] (1) is obtained by the reaction of [ReNBr2(PMe2Ph)3] with NiBr2 in tetrahydrofuran in form of dark green, air sensitive crystals crystallizing in the monoclinic space group P21/n with a = 961.44(9), b = 3692.6(4), c = 1177.8(2) pm, β = 103.42(1)°, and Z = 4. In the dinuclear complex the complex fragment [NiBr2(OPMe2Ph)] is connected by an asymmetric nitrido bridge Re≡N‐Ni with the nitrido complex [ReNBr2(PMe2Ph)3], such that the Ni atom achieves a tetrahedral coordination. The nitrido bridge is characterized by a bond angle Re‐N‐Ni of 172.7(7)° and distances Re‐N = 169(1) and Ni‐N = 195.0(9) pm.The reaction of [ReNCl2(PMe2Ph)3] with PtCl4 in THF proceeds under reduction of PtIV to yield air stable, brown crystals of [{(Me2PhP)3Cl2Re≡N}2PtCl2] (2) with the monoclinic space group P21/c and a = 1241.3(1), b = 1734.0(1), c = 1369.7(1) pm, β = 101.32(1)°, and Z = 2. The divalent Pt atom exhibits a square planar coordination with the two rhenium(V) nitrido complexes coordinated by nitrido bridges Re≡N‐Pt in trans position. The distances in the virtually linear nitrido bridge (Re‐N‐Pt = 174.0(3)°) are Re‐N = 170.6(5) pm and Pt‐N = 196.4(5) pm.The nitrido complex [OsNCl3(AsPh3)2] reacts with [Rh(μ‐Cl)(COD)]2 in CH2Cl2 to yield [(Ph3As)2Cl3Os≡N‐RhCl(COD)] (3). The heterometallic complex forms olive green, largely air stable crystals with the monoclinic space group Cc and a = 2316.8(5), b = 1169.3(1), c = 1601.4(2) pm, β = 106.12(1)°, and Z = 4. Rh(I) exhibits a square‐planar coordination with the two π bonds of the COD ligand coordinating in cis position. The osmium nitrido complex is coordinated by a linear nitrido bridge Os≡N‐Rh (Os‐N‐Rh = 176.1(7)°) with distances Os‐N = 168(1) pm and Rh‐N = 186(1) pm.The complex [(Ph3As)2Cl3Os≡N‐IrCl(COD)] (4) is obtained by the reaction of [Ir(μ‐Cl)(COD)]2 with [OsNCl3(AsPh3)2] in CH2Cl2. 4 crystallizes isotypic to 3 in form of olive brown blocks with the space group Cc and a = 2322.1(2), b = 1167.01(6), c = 1603.8(2) pm, β = 105.927(9)°, and Z = 4. The nitrido bridge Os≡N‐Ir is characterized by the bond angle Os‐N‐Ir = 176.2(8)° and distances Os‐N = 171.2(8) pm and Ir‐N = 181.5(8) pm.

Synthese und Struktur der Nitridokomplexe (Ph3Sb)2Cl3Os≡N-RhCl(COD), (Me2PhP)2(PhCN)Cl2Re≡N-RhCl2(C5Me5), [(Me2PhP)3(PhCN)ClRe≡N-OsCl2(CO)3][OsCl3(CO)3] und [(Me2PhP)3(PhCN)ClRe≡N-ReCl4-N≡ReCl(NCPh)(PMe2Ph)3][OsCl4(CO)2] / Synthesis and Structure of the Nitrido Complexes (Ph3Sb)2Cl3Os≡N-RhCl(COD), (Me2PhP)2(PhCN)Cl2Re≡N-RhCl2(C5Me5), [(Me2PhP)3(PhCN)ClRe≡N-OsCl2(CO)3][OsCl3(CO)3], and [(Me2PhP)3(PhCN)ClRe≡N-ReCl4-N≡ReCl(NCPh)(PMe2Ph)3][OsCl4(CO)2

The reaction of (Ph3Sb)2Cl3OsN with [Rh(μ-Cl)(COD)]2 in benzonitrile yields the heteronuclear nitrido complex (Ph3Sb)2Cl3Os≡N-RhCl(COD) (1). It crystallizes as dark brown blocks in the triclinic space group P1 with a = 1080.09(5), b = 1173.15(5), c = 1702.28(9) pm, α = 101.214(4), β = 92.923(8), γ = 92.836(5)֯, and Z = 2. The complex fragment RhCl(COD) is coordinated to the osmium nitrido complex via a linear nitrido bridge Os≡N-Rh, with a bond angle Os-N-Rh = 175.3(5)° and distances Os-N = 168.6(6) and Rh-N = 184.6(6) pm. The heteronuclear complexes (Me2PhP)2(PhCN)Cl2Re≡N-RhCl2(C5Me5) (2) and [(Me2PhP)3(PhCN)ClRe≡NOsCl2( CO)3][OsCl3(CO)3] (3) are obtained by the reaction of (Me2PhP)3Cl2ReN with [RhCl(μ- Cl)(C5Me5)]2 and [OsCl(μ-Cl)(CO)3]2, respectively, in benzonitrile. 2 forms orange red crystals with the composition 2・C6H5CN in the monoclinic space group P21/c and a =910.23(7), b =1255.4(1), c = 3761.5(3) pm, β = 95.617(9)° and Z = 4. The nitrido bridge Re≡N-Rh to the complex fragment [RhCl2(C5Me5)] has a bond angle Re-N-Rh of 171.9(3)° and distances Re-N = 169.4(5) and Rh-N = 201.9(5) pm. 3 forms yellow orange plates with the monoclinic space group P21/c and a = 1113.74(5), b = 2038.5(2), c = 2130.1(1) pm, β = 90.298(6)° and Z = 4. The nitrido bridge within the complex cation [(Me2PhP)3(PhCN)ClRe≡N-OsCl2(CO)3]+ is characterized by a bond angle Re-N-Os of 167.7(4)° and distances Re-N = 169.5(8) and Os-N = 206.1(8) pm. The ligands of the octahedral anion [OsCl3(CO)3]− are in a facial arrangement. The synthesis of 3 yields [{(Me2PhP)3(PhCN)ClRe≡N}2ReCl4][OsCl4(CO)2] (4) as a byproduct. It crystallizes as red brown blocks with the composition 4·CH2Cl2 in the space group P1 and a = 1444.2(1), b = 1536.3(1), c = 2150.5(2) pm, α =87.41(1), β =88.54(1), γ =62.453(8)° and Z =2. In the two symmetry independent, centrosymmetric cations [(Me2PhP)3(PhCN)ClRe≡N-ReCl4-N≡ReCl(NCPh)(PMe2Ph)3]2+ of 4 two nitrido complexes [(Me2PhP)3(PhCN)ClReN]+ coordinate with their terminal nitrido ligands a central, square planar ReCl4 unit. The resulting nitrido bridges with bond angles Re(1)-N(1)- Re(2) = 167.0(4)° and Re(3)-N(2)-Re(4) = 168.9(4)°, respectively, exhibit distances Re(1)-N(1) = 172.4(7) and Re(2)-N(1) = 197.1(7) or Re(3)-N(2) = 171.4(6) and Re(4)-N(2) = 197.1(6) pm. The two carbonyl ligands of the anion [OsCl4(CO)2]2− are in cis position.

Reactions of the Complexes ReNCl2(PMe2Ph)3, [ReNCl4]—, [OsO3N]—, and Cl3VNCl with Metal Halides

AbstractThe nitrido complexes ReNCl2(PMe2Ph)3 and [OsO3N]— have strong basic terminal nitrido ligands which can react with Lewis acidic metal halides to form nitrido bridges. The synthesis and structure of complexes with ReNCl2(PMe2Ph)3 and nitrido bridges Re≡N‐M (M = B, Ga, Sn, Ti, Zr, V, Nb, Ta, Mo, Re, Pd, Au, and Zn) as well as of complexes with [OsO3N]— and nitrido bridges Os≡N‐M (M = Pd and Pt) are reported. Strong Lewis acids can also remove phosphine or chloro ligands from ReNCl2(PMe2Ph)3. The resulting complex fragments subsequently combine to yield oligomeric complexes with nitrido bridges Re≡N‐Re. If the reaction with strong Lewis acids is carried out in a chlorinated solvent the solvent can be decomposed to form HCl which then protonates the nitrido ligand affording an imido complex. [ReNCl4]— is able to form nitrido bridges to electrophilic halides if a donor ligand is coordinated in trans position to the nitrido ligand to enhance its basicity sufficiently. The synthesis and structure of examples with nitrido bridges Re≡N‐M (M = Pd, Pt, Ta) are reported.The chloro imido complex Cl3V≡N‐Cl can act as a nitride ion transfer reagent. Its reaction with MoCl5 yields Mo2NCl8 whereas with MoCl3 the nitride chlorides Mo3N2Cl11 and MoNCl3 are obtained. Cl3VNCl can also act as an reactive intermediate by the reaction of VN with a halide as was shown by the reaction of MoCl5 with VN yielding Mo2NCl7. The structures of these molybdenum nitride chlorides are discussed.

Cover Picture: Final Reports of the Research Project „Nitrido Bridges between Transition Metals and Main Group Elements”︁ of the Deutsche Forschungsgemeinschaft (DFG) (Journal of Inorganic and General Chemistry 5/2003)

Cover Picture: <b>Final Reports</b> of the Research Project „Nitrido Bridges between Transition Metals and Main Group Elements”︁ of the Deutsche Forschungsgemeinschaft (DFG) (Journal of Inorganic and General Chemistry 5/2003)

Recent Advances in the Synthesis of N‐Heteroatom Substituted Imido Complexes Containing a Nitrido Bridge [M=N—E] (M = Group 4, 5 and 6 Metal, E = B, Si, Ge, P, S)

AbstractThe focus of the current report lies on recent developments of synthetic methods applied to the synthesis of some high‐valent complexes containing the nitrido functionality [N]3— as a link between a group 4, 5 or 6 transition metal and a main group element E (E = B, Si, Ge, P, S). Emphasis is put on results, that have been obtained within the “Schwerpunktprogramm “Nitridobrücken” funded by the Deutsche Forschungsgemeinschaft. The synthetic methods include condensation reactions of reactive chloro and oxo complexes (M = V, Nb, Ta, Cr, Mo, W) with silylamines, sulfonylamides, with N‐silyl and N‐lithio iminophosphoranes, furthermore methatesis reactions of oxo complexes with N‐sulfonyl sulfinyl amides (M = V, Cr, Mo, W), the oxidative addition of element azides to d2 metal centers (M = V, W), and finally transamination reactions of N‐H iminophosphoranes with amido complexes (M = Ti, Sm).

Oligonary Nitrides and Oxonitrides of Si, P, Al, and B in Combination with Rare Earth or Transition Metals as well as Molecular Precursor Compounds with Nitrido Bridges M‐N‐Si (M = Ti, Zr, Hf, W, Sn)

AbstractA novel synthetic approach is presented leading to hitherto unknown nitridosilicates, oxonitridosilicates, oxonitridoaluminosilicates, carbidonitridosilicates, as well as nitridoborates and oxonitridoborates of rare earth elements, alkali, and alkaline earth metals. Typically, the respective metals were reacted with silicon diimide, aluminum nitride, or poly(boron amide imide), respectively, under pure nitrogen atmosphere utilizing a radiofrequency furnace. Usually, the compounds are obtained within short reaction periods as coarsely crystalline products. Zink nitridophosphates of the sodalite structure type were obtained by the reaction of phosphorus nitride imide with zinc or zinc chalcogenides, respectively. Several molecular metal silylamides and imides containing nitridobridges between the metals and silicon were obtained by the reaction of differently chlorinated disilazanes with metal chlorides. During these investigations hitherto unknown bis(trimethylsilyl)ammonium salts have been discovered. Furthermore, we report about the synthesis of N‐silyl metal hydrazides.

Synthesis of Nitrido(phthalocyaninato)metal(V) Complexes RnPcMN (M = Re, Mo, W) and New Compounds with Nitrido‐Bridges between Rhenium and Elements of the Third Main Group

AbstractNew tetra‐ and octasubstituted nitrido(phthalocyaninato)metal(V) complexes RnPcMN (M = Re, Mo, W) were synthesized to obtain soluble nitrido‐bridged phthalocyanines. Phthalocyanines with nitrido bridges between rhenium and boron, aluminium, gallium and indium, respectively, were synthesized from nitrido(tetra‐tert.‐butylphthalocyaninato)rhenium(V) complex, tBu4PcReN and suitable electrophilic reagents like BCl3, B(C6F5)3, BPh3, BEt3, AlCl3, GaCl3, GaBr3, InCl3, etc. The nitrido‐bridged compounds prepared show different stabilities depending on the substituents at the boron atom. Additionally, the possibility to increase the nucleophilicity of (C5H11)8PcWN by reducing this complex with C8K was studied. The reaction of the reduced complex with electrophiles, e.g. with tBuMeSiCl, Ph3SiCl and Me3GeCl indicates the formation of nitrogen‐bridged complexes.

MNE Nitrido Bridges with Transition Metal Nitrogen Multiple Bonds and E = Phosphorus, Sulfur, and Chlorine

AbstractA compilation is given on new syntheses, properties, and structures of complexes with M≡N—E ↔ M=N=E nitrido bridges with transition metal nitrogen multiple bonds and participation of the main group elements E of phosporus, sulfur, and chlorine.1. MNP: This atomic sequence is realized in phosphoraneiminato complexes with transition metals in high oxidation states and termal bond of the (NPR3—) ligand. A series of new complexes of this type is reported with M = zirconium, hafnium, molybdenum, tungsten, and rhenium, among these the homoleptic species [Hf(NPPh3)4] and [M(NPPh3)4]2+ with M = Mo and W. Therefrom the isolobal complexes [:N≡Mo(NPPh3)3], [:O≡W(NPPh3)3]+, [(O)2Mo(NPPh3)2], and [(O)3Re(NPPh3)] are derived.2. MNS: Adding to compounds with this atomic sequence, new complexes were developed on the basis of the functional ligand groups thionitrosyl (a), dinitridosulphate(II) (b), dinitridosulphate(IV) (c), and cyclothiazeno (d) (cyclo‐3, 5‐dithia‐2, 4, 6‐triazino):magnified image3. MNCl: Novel N‐chloroimido complexes of tungsten are described. [F4W≡N—Cl]4, which is tetrameric according to the IR spectrum, was obtained by direct fluorination from [Cl4W≡N—Cl]2 or, surprisingly, from W(N)Cl3. With acetonitrile the monomeric molecular complex [CH3CN→WF4(≡N—Cl)] is formed. In an unexpected pathway K[F5W≡N—Cl] was obtained from a redox reaction of W(N)Cl3 with trimethylstannyl fluoride in the presence of potassium fluoride. The ionic compound forms double layers with short Cl···F contacts.

Reactions of Rhenium and Technetium Nitrido Complexes with ER3 Fragments (E = B, Ga, Al, C, P; R = H, Alkyl, Aryl)

AbstractTerminal ‘N3—’ ligands in rhenium and technetium nitrido complexes are sufficiently nucleophilic to react with Lewis acids under formation of nitrido‐bridged compounds. The reactivity of the nucleophilic centre and the nature of the formed compounds are strongly dependent on the Lewis acid and the composition of the metal complex used.Air‐stable compounds with Re≡N‐ER3 bridges are formed when ER3 is BR3 (R = H, Cl, Br, Ethyl, Phenyl, C6F5), BCl2Ph, GaCl3, CPh3+, or PPh3. The six‐co‐ordinate rhenium(V) complexes [ReNX2(PMe2Ph)3] (X = Cl, Br), [ReN(X)(Et2dtc)(PMe2Ph)2] (Et2dtc— = diethyldithiocarbamate) and [ReN(Et2dtc)2(PMe2Ph)] have been proved to be excellent starting materials for this type of reactions, whereas the five‐co‐ordinate precursors [ReNCl2(PPh3)2], [ReN(Et2dtc)2], [ReN{Ph2P(S)NP(S)Ph2}2] or [ReNCl4]— only react with the most reactive Lewis bases of the examples mentioned above such as BCl2Ph or B(C6F5)3. The rhenium‐nitrido bond lengths remain almost unchanged by the adduct formation, whereas a significant decrease of the trans‐influence of the nitrido complexes has been observed as can be seen by a shortening of the corresponding bond lengths or dimerization of five‐co‐ordinate precursors.Electrophilic attack of the Lewis acid to a donor atom of the equatorial co‐ordination sphere of the rhenium complex results in the formation of ‘underco‐ordinate’ metal centres which resemble to di‐, tri or tetrameric units with asymmetric nitrido bridges between each two rhenium atoms.EPR spectroscopy is an excellent tool to reflect the formation of nitrido bridges at the paramagnetic (d1) [ReNX4]— core (X = F, Cl, Br, NCS). The spectral parameters derived for the products of reactions of [ReNCl4]— with various boron compounds indicate an increase of the covalency of the equatorial Re‐L bonds as a consequence of the formation of a nitrido bridge.The tendency for the formation of nitrido bridges with Lewis acids is significantly lower for technetium compounds compared to their rhenium analogues. Only a few examples with BH3 and BPhCl2 have been established.

Nitrido Bridges between Electrophilic Phosphorus Centers of S-, P- and D-Block Metals

Nitrido Bridges between Electrophilic Phosphorus Centers of S-, P- and D-Block Metals

Tc(NBCl2Ph)Cl2(Me2PhP)3] und [Tc(NBH3)Cl2(Me2PhP)3] - die ersten Technetium-Komplexe mit Nitridobrücken zwischen Technetium und Bor

[Tc(NBCl2Ph)Cl2(Me2PhP)3] and [Tc(NBH3)Cl2(Me2PhP)3] – the First Technetium Complexes with Nitrido Bridges between Technetium and Boron [TcNCl2(Me2PhP)3] reacts with BCl2Ph or BH3 · THF at low temperatures under formation of complexes containing a nitrido bridge between technetium and boron. The compounds are instable and decompose at room temperature under cleavage of the N–B bonds. The pale-purple [Tc(NBCl2Ph)Cl2(Me2PhP)3] crystallizes in the orthorhombic space group Fdd2. The Tc≡N bond is only slightly lengthened by the formation of the N–B bond of 1.564(4) A. However, a considerable lengthening of the Tc–Cl bond in trans position to the nitrido ligand is observed which can be attributed to an decreasing of the structural trans influence of the nitrido moiety. A similar structural feature can be found in [Tc(NBH3)Cl2(Me2PhP)3] which is the first structurally characterized transition metal complex containing a nitrido bridge to unsubstituted borane.

ChemInform Abstract: Nitrido Bridges Between Transition Metals and Main Group Elements Illustrated by the Series [M]NNa to [M]NCl

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthese und Strukturen von [ReNBr2(Me2PhP)3] und (Me2PhPH)[fac-Re(NBBr3)Br3(Me2PhP)2

Syntheses and Structures of [ReNBr2(Me2PhP)3] and (Me2PhPH)[fac-Re(NBBr3)Br3(Me2PhP)2] [ReNBr2(Me2PhP)3] (1) has been prepared by the reaction of [ReNCl2(Me2PhP)3] with Me3SiBr in dichloromethane. The bromo complex reacts with BBr3 under formation of [Re(NBBr3)Br2(Me2PhP)3] (2) or (Me2PhPH)[fac-Re(NBBr3)Br3(Me2PhP)2] (3) depending on the experimental conditions. The formation of the nitrido bridge leads to a significant decrease of the structural trans influence of the nitrido ligand which is evident by the shortening of the Re-(trans)Br bond from 2.795(1) A in [ReNBr2(Me2PhP)3] to 2.620(1) A in [fac-Re(NBBr3)Br3(Me2PhP)2]– and 2.598(1) A in [Re(NBBr3)Br2(Me2PhP)3], respectively.