A study of ortho- and para-siloxyanilines for the synthesis of mono-, bi-, and tetra-nuclear early transition metal–imido complexes

The siloxyanilines o-Me₃SiOC₆H₄NH₂ (1) and p-RMe₂SiOC₆H₄NH₂ (R=H (2); R=Me (3)), and their N-silylated derivatives p-Me₃SiOC₆H₄NHSiMe₃ (4) and p-Me₃SiOC₆H₄N(SiMe₃)₂ (5) have been prepared from ortho- or para-aminophenol and used in the synthesis of imido complexes. Thus, binuclear [{Ti(η⁵-C₅H₅)Cl}{μ-NC₆H₄(p-OSiMe₃)}]₂ (6) and mononuclear [TiCl₂{NC₆H₄(p-OSiMe₃)}(py)₃] (7) imido complexes have been obtained from the reaction of 3 and [Ti(η⁵-C₅H₅)Cl₃] or [TiCl₂(N^tBu)(py)₃], respectively. In contrast, the reaction of 1 with TiCl₄ and ^tBupy affords the titanocycle [TiCl₂{OC₆H₄(o-NH)---N,O}(^tBupy)₂] (8). Compound 5 has also been used to prepare the niobium imide complex [NbCl₃{NC₆H₄(p-OSiMe₃)}(MeCN)₂] (9), by its reaction with NbCl₅ in CH₃CN. These findings have been applied to the synthesis of polynuclear systems. Thus, chlorocarbosilane Si[CH₂CH₂CH₂Si(Me)₂Cl]₄ (CS–Cl) has been functionalized with the ortho- and para-aminophenoxy groups to give 10 and 11, respectively. The use of 11 has allowed the formation of the tetranuclear compound 12. Attempts to synthesize terminal imido titanium complexes from 10 and TiCl₄ in the presence of ^tBupy and Et₃N, give complex 8 and carbosilane CS–Cl.     

二(甲基环戊二烯基)二氯化钛及某些取代苯氧基衍生物的合成

二(甲基环戊二烯基)二氯化钛[(MeCp)₂TiCl₂](Ⅰ),Wilkinson等人^[1]曾用四氯化钛和甲基环戊二烯基钠反应来制备,产率26％.后来Brantly^[2]用四氯化钛和MeC₅H₄MgCl在乙醚-苯混合溶液中于-70℃反应.以上两种方法不但操作复杂,且条件苛刻,产率低.最近吴绍祖等^[3]用二乙胺作为氯化氢的接受体,四氢呋喃作溶剂,由TiCl₄和甲基环戊二烯直接反应来合成.产率43％.我们采用甲基环戊二烯基锂与TiCl₄反应来合成,产率为63％.     

New organogold(I) complexes: Synthesis, structure, and dynamic behavior of the polynuclear organogold diphenylmethane and diphenylethane derivatives

Two organogold derivatives of diphenylmethane and diphenylethane, Ph₃PAu(o-C₆H₄)CH₂(C₆H₄-o)AuPPh₃ (1) and Ph₃PAu(o-C₆H₄)(CH₂)₂(C₆H₄-o)AuPPh₃ (2), have been synthesized by the reaction of ClAuPPh₃ with Li(o-C₆H₄)CH₂(C₆H₄-o)Li and Li(o-C₆H₄)(CH₂)₂(C₆H₄-o)Li respectively. The interaction of 1 with dppe results in the replacement of the two PPh₃ groups to give a macrocyclic compound (3) that includes an Au Au bond. Compounds 1 and 2 react with one or two equivalents of [Ph₃PAu]BF₄ to form new types of cationic complex [CH₂(C₆H₄-o)₂(AuPPh₃)₃]BF₄ (4), [CH₂(C₆H₄-o)₂(AuPPh₃)₄](BF₄)₂ (5), and [(CH₂)₂(C₆H₄-o)₂(AuPPh₃)₄](BF₄)₂ (6). Complexes 1–6 have been characterized by X-ray diffraction studies, FAB MS, and IR as well as by ¹H and ³¹P NMR spectroscopy. A complicated system of Au H-C agostic interactions, involving the bridging alkyl groups (—CH₂— and CH₂-CH₂—) of diphenylmethane and diphenylethane ligands, has been found to occur in complexes 1–3 and 6.     

Synthesis of metallocenes of zirconium, hafnium, manganese, iron, tin, lead and half-sandwich complexes of rhodium and iridium containing the ligands (η-C5R4CR′2PMe2), where R and R′ may be H or Me

The dimethylphosphino substituted cyclopentadienyl precursor compounds [M(C₅Me₄CH₂PMe₂)], where M=Li⁺ (1), Na⁺ (2), or K⁺ (3), and [Li(C₅H₄CR′₂PMe₂)], where R′₂=Me₂ (4), or (CH₂)₅ (5), [HC₅Me₄CH₂PMe₂H]X, where X⁻=Cl⁻ (6) or PF₆⁻ (7) and [HC₅Me₄CH₂PMe₂] (8), are described. They have been used to prepare new metallocene compounds, of which representative examples are [Fe(η-C₅R₄CR′₂PMe₂)₂], where R=Me, R′=H (9); R=H and R′₂=Me₂ (10), or (CH₂)₅ (11), [Fe(η-C₅H₄CMe₂PMe₃)₂]I₂ (12), [Fe{η-C₅Me₄CH₂P(O)Me₂}₂] (13), [Zr(η-C₅R₄CR′₂PMe₂)₂Cl₂], where R=H, R′=Me (14), or R=Me, R′=H (15), [Hf(η-C₅H₄CMe₂PMe₂)₂]Cl₂] (16), [Zr(η-C₅H₄CMe₂PMe₂)₂Me₂] (17), {[Zr(η-C₅Me₄CH₂PMe₂)₂]Cl}{(C₆F₅)₃BClB(C₆F₅)₃} (18), [Zr{(η-C₅Me₄CH₂PMe₂)₂Cl₂}PtI₂] (19), [Mn(η-C₅Me₄CH₂PMe₂)₂] (20), [Mn{(η-C₅Me₄CH₂PMe₂B(C₆F₅)₃}₂] (21), [Pb(η-C₅H₄CMe₂PMe₂)₂] (23), [Sn(η-C₅H₄CMe₂PMe₂)₂] (24), [Pb{η-C₅H₄CMe₂PMe₂B(C₆F₅)₃}₂] (25), [Pb(η-C₅H₄CMe₂PMe₂)₂PtI₂] (26), [Rh(η-C₅Me₄CH₂PMe₂)(C₂H₄)] 29, [M(η,κP-C₅Me₄CH₂PMe₂)I₂], where M=Rh (30), or Ir, (31).     

Metallorganische lewissäuren : XX. Reaktionen von (π-C5H5)(CO)2LM-X (L = CO, PR3; M = Mo, W; X = BF4, PF6, AsF6, SbF6) mit Schwefel-haltigen liganden

The compounds (π-C₅H₅)(CO)₂LM-X (L = CO, PR₃; M = Mo, W; X = BF₄, PF₆, AsF₆, SbF₆) react with H₂S, p-MeC₆H₄SH, Ph₂S and Ph₂SO(L′) to give ionic complexes [(π-C₅H₅)(CO)₂LML′]⁺ X⁻. Also sulfur-bridged complexes, [(π-C₅H₅)(CO)₃W---SH---W(CO)₃(π-C₅H₅)]⁺ AsF₆⁻ and [(π-C₅H₅)(CO)₃M-μ-S₂C=NCH₂Ph-M(CO)₃(π-C₅H₅)], have been obtained. Reactions with SO₂ and CS₂ have been examined.     

On the synthesis and structure of monoaryllead and diaryllead acetates RPb(OCOCH3)3 and R2Pb(OCOCH3)2

Anhydrous monoaryllead triacetates ArPb(OAc)₃ (Ar = Ph, p-Tolyl, o-Tolyl, 2,5-Xylyl; OAc = OCOMe) were prepared by arylation of Pb(OAc)₄ with ArSn(C₄H₉-n)₃ in the presence of Hg(OCOCF₃)₂. The procedure was adapted for the synthesis of diaryllead diacetates Ar₂Pb(OAc)₂ (Ar = Ph, p-Tolyl, o-Tolyl, p-ClC₆H₄, o-ClC₆H₄) and afforded products with higher purity than other procedures. The crystal structures of PhPb(OAc)₃, Ph₂Pb(OAc)₂ and (o-Tolyl)₂Pb(OAc)₂ were determined by X-ray diffraction. PhPb(OAc)₃ and (o-Tolyl)₂Pb(OAc)₂ are monomeric. The pentagonal bipyramid around Pb in PhPb(OAc)₃, like the trapezoidal bipyramid around Pb in (o-Tolyl)₂Pb(OAc)₂, is heavily distorted, the OAc groups being unsymmetrically chelating. Lead in Ph₂Pb(OAc)₂ is in a distorted octahedral environment. One OAc group is bridging, linking the molecular units to infinite chains, the other OAc group is symmetrically chelating. IR, ¹H, ¹³C and ²⁰⁷Pb NMR spectroscopic data are reported. The structures of p-TolPb(OAc)₃, o-TolPb(OAc)₃ and 2,5-XylPb(OAc)₃ are inferred to be similar to that of PhPb(OAc)₃, and the structure of (o-ClC₆H₄)₂Pb(OAc)₂ is inferred to be similar to that of (o-Tolyl)₂Pb(OAc)₂.     

Preparation and study of cyclic polynuclear ferrocenes derived from (C6H5)2PCH2CH2Si(CH3)2C5H4Li as a bridging ligand

The synthesis of the potential bridging ligand (C₆H₅)₂PCH₂CH₂Si(CH₃)₂C₅H₄ (3) is described. The ferrocene (6 derived from 3 has been found to form macrocyclic complexes with metal fragments NiCl₂, NiBr₂, and Co₂(CO)₆. Although monomeric, bimetallic products might have been expected based upon the reduced steric demands of ligand 3 relative to an analogous ligand, (C₆H₅)₂PCH₂Si(CH)₃)₂C₅H₄ (1), it appears that the increased flexibility in 3 is the overriding factor leading to a preference for inter- rather than intramolecular coordination of the second phosphine function in 6.     

联苯基桥连双核茂锆化合物的合成及催化乙烯聚合

4,4′-二溴联苯与n-BuLi反应得到对-联苯基二锂,再与四甲基环戊烯酮进行羰基加成,酸催化脱水,一步得到对-联苯基桥连四甲基环戊二烯配体4-(C₅Me₄H)C₆H₄-C₆H₄(C₅Me₄H)-4(1).配体1相继与n-BuLi和ZrCl₄反应得到相应的联苯基桥连双(单茂三氯化锆)4-(C₅Me₄ZrCl₃)C₆H₄-C₆H₄(C₅Me₄ZrCl₃)-4,不经分离直接与环戊二烯基锂或茚基锂反应得到相应的双核锆化合物4-(C₅MeZrCl₂Cp′)C₆H₄-C₆H₄·(C₅Me₄ZrCl₂Cp′)-4[Cp′=C₅H₅(2),C₉H₇(3)].研究了在MAO(MethylAluminoxane)助催化下,化合物2和3对乙烯聚合的催化性能.化合物2和3都显示了非常高的催化活性,并在较高的温度下达到最高活性.     

Novel iodoammonium cations: Synthesis and characterization of o-C6H4(NH2)2IX (X = I, AsF6, AlI4)

The new iodoammonium salts o-C₆H₄(NH₂)₂I⁺I⁻ (1) and o-C₆H₄(NH₂)₂I⁺ AsF₆⁻ (2) were prepared by reaction of o-phenylene diamine with I₂ or I₃⁺AsF₆⁻, respectively. Compound 1 reacts with AlI₃ yielding quantitatively the corresponding tetraiodoaluminate o-C₆H₄(NH₂)₂I⁺AlI₄⁻ (3). The species were characterized by chemical analysis, vibrational (IR and Raman) and temperature-dependent ¹H NMR spectropscopy. Direct evidence for a N---I bond was found in the Raman spectra of 1, 2 and 3 (ν(NI) = 599–600 cm⁻¹).     

Substituent effects on the frontier molecular orbitais of aryl isonitriles

An investigation of the frontier molecular orbitais ofo- and p-RC₆H₄NC (R=H, CH₃, NO₂, F, Cl, CF₃, OCH₃) was carried out so that a thorough understanding of the intricacies of σ donation and π acceptance could be developed and used to modify subtly the electron density on metal centers. The results of this study-Indicate that the substituent position (ortho vs. para ) does alter the electron density in the ligand appreciably and that substitution of the phenyl ring with the groups indicated has a smaller effect on the σ-donating ability than it does on the π-accepting ability of the isonitrile ligand.

The π-accepting abilities of the isonitrile ligands increase in the order o-, p-CH₃OC₆H₄NC, o-, p-CH₃C₆H₄NC, o-, p-C₆H₅NC, o-, p-FC₆H₄NC, o-, p-CF₃C₆NC, o-, p-ClC₆H₄NC, o-, p-NO₂C₆H₄NC while the σ-donating ability decreases in this order. The energies of the σ-donor and π-acceptor orbitais are shown to correlate well with observed E values of Cr(RC₆H₄NC)₆ and Mn(RC₆H₄NC)₆⁺¹ complexes. This demonstrates how the theoretical results can be useful in understanding the observed physical properties of isonitrile-metal complexes.     

Preparation and reactions of some sterically hindered silanols, including [tris(trimethylsilyl)methyl]silanetriol

The silanol TsiSiMe₂OH (Tsi = (Me₃Si)₃C) has been made by hydrolysis of the iodide TsiSiMe₂I in H₂O/dioxane or H₂O/Me₂SO. It has been shown to react with some acid chlorides RCOCl (R=Me, Et, CICH₂ Ph, 4-O₂NC₆H₄, and 3,5- (O₂N)₂C₆H₃) and anhydrides (RCO)₂O (R = Me, CF₃, or Ph) to give the carboxylates TsiSiMe₂OCOR, and with SO₂Cl₂ to give TsiSiMe₂OSO₂Cl. The triol TsiSi(OH)₃ has been made by treatment of TsiSiH(OH)I with H₂O/Me₂SO at 150°C or with a mixture of aqueous AgClO₄ and an organic solvent. The triol has been shown to react with RCOCl (R = Me, Et, or Ph) or (RCO)₂O (R = Ph) to give the corresponding TsiSi(OCOR)₃, with (CF₃CO)₂O to give TsiSi(OH)₂(OCOCF₃), and with a mixture of Me₃SiCl and AgClO₄ in benzene or one of Me₃Sil and (Me₃Si)NH to give TsiSi(OSiMe₃)₃. The triol is unusually stable, but decomposes at its m.p. of 285–290°C.     

含芳香双酯高效催化剂进行丙烯聚合及其动力学的研究

采用多种芳香双酯作为电子给予体制备了丙烯聚合高效催化剂,该催化剂具有高活性、聚合反应平稳、产物等规度高等特征.研究了多种芳香双酯和外加各种烷基硅氧烷对丙烯聚合的作用,测定了聚合反应动力学曲线,确定了聚合动力学方程.用扫描电镜研究了催化剂的形态,表明双酯组份能使催化剂结合得较紧密;对聚合产物的结构用DSD、红外光谱进行了表征.     

The chemistry of compounds of the type Ru(η---C5Me4Et)(CO)2X (X=Cl, Br or I)

The title compounds react with unidentate ligands, L, containing either phosphorus or arsenic donor atoms to yield the corresponding compounds of the type Ru(η⁵---C₅Me₄Et)(CO)LX; with didentate phosphorus donor ligands the major species formed is the bridged complex {Ru(η⁵---C₅Me₄Et)(CO)X}₂{Ph₂P(CH₂)_nPPh ₂} n = 1, X = Br; n = 2, X = Cl). In contrast, unidentate ligands containing nitrogen donor atoms such as pyridine did not react with Ru(η⁵---C₅Me₄Et)(CO)₂Cl although reaction with 1,10-phenanthroline or diethylenetriamine yielded the ionic products [Ru(η⁵---C₅Me₄Et)(CO)L]⁺Cl⁻ (L = phen or (NH₂CH₂CH₂)₂NH). Reaction of Ru(η⁵---C₅Me₄Et)(CO)₂Br with AgOAc yielded the corresponding acetato complex Ru(η⁵---C₅Me₄Et)(CO)₂0Ac. Ru(η⁵--- C₅Me₄Et)(CO)₂X reacts with AgY (Y = BF₄ or PF₆) in either acetone or dichloromethane to give the useful solvent intermediates [Ru(η⁵---C₅Me₄Et)(CO)₂(solvent)]⁺Y⁻, which readily react with ligands L to yield ionic derivatives of the type [Ru(η⁵---C₅Me₄Et)(CO)₂L]⁺Y⁻ (where L = CO, NCMe, py, C₂H₄ or MeO₂CCCCO₂Me).     

Synthesis and properties of alkyldicyclopentadienyl-vanadium(III) compounds

The compounds Cp₂VR (R = CH₃, C₂H₅, n-C₃H₇, n-C₄H₉, n-C₅H₁₁, CH₂C(CH₃)₃ or CH₂Si(CH₃)₃) have been prepared from Cp₂ VCl and RMgX in n-pentane. The air-sensitive compounds are stable at room temperature, but decompose between 65 and 138°C. The thermal stability decreases in the order R = CH₃ CH₂Si(CH₃)₃ > C₂H₅ > CH₂C(CH₃)₃ > n-C₅H₁₁ > n-C₄H₉ > n-C₃H₇. Compounds with R = i-C₃H₇ or t-C₄H₉ could not be obtained.     

Systematische untersuchungen über das verhalten von organozinnverbindungen gegenüber flüssigem schwefeldioxid II. Reaktionen von arylstannanen mit flüssigem SO2

The behaviour of tetraarylstannanes, R₄Sn (R = C₆H₅CH₂, C₆H₅, o-, m-, p-CH₃C₆H₄), towards SO₂ under various conditions has now been studied in detail. Compared to aliphatic tetraorganostannanes, the variability of the reaction products is much less, so that in nearly all cases only disulfinates, R₂Sn(O₂SR)₂, are formed. The aromatic tin(IV) mono-, di- and tri-sulfinates are also obtained by metathetical reaction between the corresponding organotin halides and sodium sulfinates. A unique feature of triaryltin chlorides, R₃SnCl (R = C₆H₅, o-, m-, p-CH₃C₆H₄), is their disproportionation in liquid SO₂ leading to disulfinates, R₂Sn(O₂SR)₂, and dichlorides, R₂SnCl₂. (p-CH₃C₆H₄)₂SnCl₂, under more efficient conditions, also accepts SO₂ forming (p-CH₃C₆H₄SO₂)₂SnCl₂. The structural investigations of the newly prepared compounds are carried out on the basis of their IR and ¹H NMR spectra.     

Preparation and characterization of ruthenium(II), rhodium(III) and iridium(III) complexes of isocyanide bearing the azo group

Reactions of [(η⁶-arene)RuCl₂]₂ (1) (η⁶-arene=p-cymene (1a), 1,3,5-Me₃C₆H₃ (1b), 1,2,3-Me₃C₆H₃ (1c) 1,2,3,4-Me₄C₆H₂(1d), 1,2,3,5-Me₄C₆H₂ (1e) and C₆Me₆ (1f)) or [Cp*MCl₂]₂ (M=Rh (2), Ir (3); Cp*=C₅Me₅) with 4-isocyanoazobenzene (RNC) and 4,4′-diisocyanoazobenzene (CN–R–NC) gave mononuclear and dinuclear complexes, [(η⁶-arene)Ru(CNC₆H₄N=NC₆H₅)Cl₂] (4a–f), [Cp*M(CNC₆H₄N=NC₆H₅)Cl₂] (5: M=Rh; 6: M=Ir)_, [{(η⁶-arene)RuCl₂}₂{μ-CNC₆H₄N=NC₆H₄NC}] (8a–f) and [(Cp*MCl₂)₂(μ-CNC₆H₄N=NC₆H₄NC)}] (9: M=Rh; 10: M=Ir)_, respectively. It was confirmed by X-ray analyses of 4a and 5 that these complexes have trans-forms for the ---N=N--- moieties. Reaction of [Cp*Rh(dppf)(MeCN)](PF₆)₂ (dppf=1,1′-bis (diphenylphosphino)ferrocene) with 4-isocyanoazobenzene gave [Cp*Rh(dppf)(CNC₆H₄N=NC₆H₅)](PF₆)₂ (7), confirmed by X-ray analysis. Complex 8b reacted with Ag(CF₃SO₃), giving a rectangular tetranuclear complex 11b, [{(η⁶-1,3,5-Me₃C₆H₃)Ru(μ-Cl}₄(μ-CNC₆H₄N=NC₆H₄NC)₂](CF₃SO₃)₄ bridged by four Cl atoms and two μ-diisocyanoazobenzene ligands. Photochemical reactions of the ruthenium complexes (4 and 8) led to the decomposition of the complexes, whereas those of 5, 7, 9 and 10 underwent a trans-to-cis isomerization. In the electrochemical reactions the reductive waves about −1.50 V for 4 and −1.44 V for 8 are due to the reduction of azo group, [---N=N---]→[---N=N---]²⁻. The irreversible oxidative waves at ca. 0.87 V for the 4 and at ca. 0.85 V for 8 came from the oxidation of Ru(II)→Ru(III).     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden : XX. “Ylidreaktionen” einfacher dicarbonyl(pentamethylcyclopentadienyl)rutheniumkomplexe

Treatment of the dimer complex [C₅Me₅ (CO)₂ Ru]₂ (1) with HBF₄ in CH₂Cl₂ at room temperature yields the hydrido-bridged dinuclear complex [(C₅Me₅)₂Ru₂(CO)₄H]BF₄ (2), and after refluxing in propionic anhydride [C₅Me₅(CO)₃Ru]BF₄ (5) is obtained, UV-irradiation of 1 in the presence of H₂CHal₂ (Hal = Cl, I) or trimethylphosphine leads to the formation of C₅Me₅(CO)₂Ru-Hal (3a, 3b) or C₅Me₅(CO)(Me₃P)RuH (4) respectively. Exchange reactions of 3a, 3b with LiAlH₄, NaOMe and Me₃ P give the complexes C₅Me₅(CO)₂RuX (6a,6b) (X=H, OMe), C₅Me₅(CO)(Me₃P)Ru-Hal (7a,7b) (Hal = Cl, I) and C₅Me₅(Me₃P)₂RuI (8). The interaction of 3b or 5 with Me₃P=CH₂ leads to the formation of the ylide complex [C₅Me₅(CO)(Me₃P)-RuCH₂PMe₃)Cl (9) or the rutheniumacyl-ylide C₅Me₅(CO)₂RuC(O)CH=PMe₃ (10). 4 reacts with Me₃P=CH₂ to give C₅Me₅(CO)(Me₃P)RuMe (11) and Me₃P via the intermediate formation of the phosphonium salt Me₄P[Ru(CO) (Me₃P)-C₅Me₅].     

Synthesis, structure and properties of delocalized transition metal chelates: Diazoketiminato chelates of Co(III) and Pt(II)

The reactions of HL 1 [where HL is 1N-(2-pyridyl-2-methyl)-2-arylazoaniline and is formulated as ArN = NC₆H₄N(H)(CH₂C₅H₄N); Ar = C₆H₅ (for HL¹) or p-MeC₆H₄ (for HL²) or p-ClC₆H₄ (for HL³)] with K₂PtCl₄ and Co(ClO₄)₃ · 6H₂O afforded the (L)PtCl and [(L)₂Co]ClO₄ complexes, respectively. The HL ligands bind the platinum(II) and cobalt(III) centres in a tridentate (N,N,N) fashion, forming new diazoketiminato chelates upon dissociating the amino proton. The X-ray structures of (L³)PtCl and [(L³)₂Co]ClO₄ were determined. Redox properties of the new complexes have been examined.     

Organonickel chemistry in the catalytic hydrodechlorination of polychlorobiphenyls (PCBs): ligand steric effects and molecular structure of reaction intermediates

Soluble homogeneous organophosphorus—nickel complexes have been used to detoxify polychlorinated biphenyls (PCBs) by catalyzed hydrodechlorination using NaBH₂(OCH₂CH₂OCH₃)₂ as the hydrogen source. The reactions appear to proceed by NiL₃ oxidative addition into C---Cl bonds followed by hydrogenolysis of the metal---carbon bond. In model experiments with decachlorobiphenyl, the cone angle of the organophosphorus ligand L was shown to be a key factor controlling the magnitude and position of chlorine displacement. Hence, ligands leading to para displacement (e.g. (o-MeC₆H₄O)₃P), meta—para displacement (e.g. (EtO)₃P and (PhO)₃P), and ortho—meta—para displacement (e.g. Me₃P and Et₃P) were found. Significantly, the highly toxic, coplanar dioxin precursor 3,3′,4,4′-tetrachlorobiphenyl, a meta—para chlorine-substituted congener, was dechlorinated quantitatively with the Et₃P catalyst system. Evidence for the presence of organonickel intermediates in the reaction mixtures was obtained by mass spectroscopic and X-ray diffraction studies. Of particular interest is the isolation of square planar complexes p-C₆Cl₅C₆Cl₄Ni(PEt₃)₂Cl from the reaction of decachlorobiphenyl with NaBH₂(OCH₂CH₂OCH₃)₂—(Et₃P)₂NiCl₂ as the catalyst precursor and m-C₆Cl₅C₆Cl₄Ni(PEt₃)₂Cl from decachlorobiphenyl—Ni(1,5-C₈H₁₂)₂—PEt₃ at room temperature. All are oxidative addition intermediates and precursors for decachlorobiphenyl hydrodechlorination.     

Thirty years of organometallic aryldiazenido arylazo derivatives

The aryldiazenido ligands provide the fourth member of the isoelectronic series CO, NO⁺, RNC, RN₂⁺ of ligands for transition metal complexes. The first aryldiazenido metal complex was reported in 1964 when p-CH₃OC₆H₄N₂Mo(CO)₂C₅H₅ was prepared by the reaction of NaMo(CO)₃C₅H₅ with p-CH₃OC₆H₄N₂⁺BF₄⁻. This review surveys the development of organometallic aryldiazenido chemistry since that time. Such organometallic aryldiazenido derivatives, including RN₂M(CO)₂C₅H₅, RN₂M(CO)₂(Pz₃BH) (M = Cr, Mo, W), [(η⁶-Me₆C₆)Cr(CO)₂N₂Ar]⁺, [(MeC₁₅H₄)M′(CO)₂N₂Ar]⁺ M′ = Mn, Re), [trans-PhN₂Fe(CO)₂(PPh₃)₂]⁺, and PhN₂M′(CO)₂(PPh₃)₂(PPh₃)₂ can be obtained by reactions of arenediazonium salts with suitably chosen transition metal nucleophiles. Analogous methods cannot be used to prepare alkyldiazenido transition metal complexes because of the instability of alkyldiazonium salts. However, the alkyldiazenido derivatives RCH₂N₂M(CO)₂C₅H₅ (R = H or Me₃Si) can be obtained from HM(CO)₃C₅H₅ and the corresponding diazoalkanes. Important aspects of the chemical reactivity of RN₂M(CO)₂Q derivatives (Q = C₅H₅, Pz₃BH) include CO substitution reactions, coordination of the second nitrogen in the RN₂ ligand to give heterobimetallic complexes such as C₅H₅Mo(CO)₂(μ-NNC₆H₄Me)(CO)₂C₅H₅, oxidative addition rections with X₂ X = Cl, Br, I), SnX₄, RSSR, and CINO, and reactions with further RN₂⁺ to give bis(aryldiazenido) derivatives (RN₂)₂MQL⁺ (L = CO, X⁻, etc.). Dearylation of an aryldiazenido ligand to a dinitrogen ligand can be effected by reaction of [(MeC₅H₄)M′(CO)₂N₂Ar]⁺ with certain nucleophiles to give (MeC₅H₄)M′(CO)₂N₂.