The reactivity of dimethylaluminum hydride with the aminoarsines Me2AsNMe2, MeAs(NMe2)2, and As(NMe2)3

The reactions of (Me₂AlH)₃ with Me₂AsNMe₂, MeAs(NMe₂)₂, and As(NMe₂)₃ were investigated as a function of time at room temperature and over the temperature range −90 to 24°C by use of ¹H and ¹³C NMR spectroscopy. (Me₂AlH)₃ was found to be very reactive toward the aminoarsines, even at −90°C, and no stable Me₂AlH-aminoarsine adducts were observed. Instead, the initial stages of the reactions involved AS---N bond cleavage with the generation of highly reactive AlN- and AsH-bonded species. The subsequent course of each reaction and the final arsenic-containing product distribution depended upon the original AL:N stoichiometric ratio and the respective aminoarsine. When the Al:N ratio was 1:1, the reactions were straightforward for each aminoarsine. However, in every case, [Me₂AlNMe₂]₂ was the final AlN-containing product. Independent reactions were carried out to verify many of the proposed decomposition pathways that lead to thermodynamically stable products. The results of this study are compared with those of the analogous, previously reported (Me₃Al)₂-aminoarsine systems. Additionally, a new synthetic route to [Me₂AlAsMe₂]₃ has been established from the reaction of (Me₂AlH)₃ with Me₂AsH.     

Reactions of the sterically hindered organosilicon diol (Me3Si)2C(SiMe2OH)2 and some of its derivatives

The diol R₂C(SiMe₂OH)₂ (R = Me₃Si) has been shown to react with: SO₂Cl₂ to give R₂ Me₂; SOCl₂ to give R₂C(SiMe₂Cl)₂; Me₃SiI or Me₃SiCl to give R₂C(SiMe₂OSiMe₃)₂; R′COCl; (R′ = Me or CF₃) to give R₂C(SiMe₂O₂CR′)-(SiMe₂Cl); (R′CO)₂O (R′ = Me or CF₃ to give R₂C(SiMe₂O₂CR′)₂; with MeOH containing acid to give R₂C(SiMe₂OMe)₂; with neutral MeOH to give R₂C-(SiMe₂OMe)₂ and probably R₂ Me₂; MeLi to give R₂C(SiMe₂OLi)₂ (and the latter to react with PhMeSiF₂ to give R₂ Me₂). The diacetate R₂C(SiMe₂O₂CMe)₂ reacts with CsF in MeCN to give R₂C(SiMe₂F)₂; it does not react with NaN₃ or KSCN in MeCN, but the bis(trifluoroacetate) reacts with these salts with KOCN to give R₂C(SiMe₂X)₂ (X = N₃, NCS, NCO).     

Snthesis and x-ray structure of an isomeric cyclophosphazene complex containing antimony(III)

The monosilylated acyclic phosphazene ligand Me₃SiNP(NMe₂)₂NP(NMe₂)₂ NH₂ (3) has been synthesized and characterized. The reaction of 3 with antimony triacetate, Sb(OOCMe₃), in refluxing toluene forms a cyclic phosphazene derivative, [N{P(NMe₂)₂NH}₂Sb(OOCMe)₂ (4), which is characterized by elemental analyses, mass, IR and NMR spectroscopy and single-crystal X-ray structural analysis. Complex 4 crystallizes in the form of a cis and trans isomeric chain in the solid state.     

Pseudoelementverbindungen IX. Organostannylierung von Cyanamidonitrat — Molekül- und Kristallstruktur von N-Trimethylstannyl-N′-nitro-carbodiimid

Considered under the aspect of its ambidence, the reactivity of cyanamidonitrate [NO₂NCN]⁻ towards triorganostannyl chlorides was investigated. The reaction products of type R₃Sn-NCN-NO₂ were characterized by ¹H-NMR, ¹³C-NMR, ¹¹⁹Sn-NMR and IR spectroscopy. While cyanamides of the type [R_nE(Y)NCN]⁻ (R_nE(Y) = RC(O), RC(NCN), R₂ P(O), R₂P(S), R₂P(NCN), RSO₂) are coordinated exclusively either via the terminal nitrogen (monodentately) or via both the nitrile group end on and the chalcogen atom (bidentately), we found N-triorganostannyl-N′-nitro-carbodiimides as the first example in which the NCN group acts as a bidentate bridge with metal-N bonds in 1- and 3-position. For Me₃Sn-NCN-NO₂ the crystal structure was determined.

Zusammenfassung

Unter dem Aspekt der Ambidenz wurde die Reaktivität von Cyanamidonitrat [NO₂NCN]⁻ gegenüber Triorganostannylchloriden untersucht. Die Reaktionsprodukte des Typs R₃Sn-NCN-NO₂ wurden ¹H-NMR-, ¹³C-NMR-, ¹¹⁹Sn-NMR- sowie IR-spektroskopisch charakterisiert. Während Cyanamide des Typs [R_nE(Y)NCN]⁻ (R_nE(Y) = RC(O), RC(NCN), R₂P(O), R₂P(S), R₂P(NCN), RSO₂) ausschlieβlich über das terminale Stickstoff- (einzähnig) bzw. über das Nitrilstickstoff- und das Chalkogenatom (zweizähnig) gebunden werden, fanden wir mit N-Triorganostannyl-N′-nitro-carbodiimiden erstmalig Beispiele, in denen die NCN-Gruppe zweizähnig verbrückend in 1- und 3-Position koordiniert wird. Für Me₃Sn-NCN-NO₂ liegt eine Kristallstrukturbestimmung vor.     

Titanium imido complexes containing 1,3,5-triazacyclohexane ligands

The syntheses of the 1,3,5-trimethyl- and tri-tert-butyl-1,3,5-triazacyclohexane-supported imido complexes [M(NR)(R′₃tach)Cl₂] (M = Ti or Zr (NMR only); R = Bu^t or 2,6-C₆H₃Prⁱ₂; R′ = Me or Bu^t) are reported, along with that of the thermally robust dibenzyl derivative [Ti(NBu^t)(Me₃tach)(CH₂Ph)₂]. The tert-butylimido ligand in [Ti(NBu^t)(Me₃tach)Cl₂] undergoes exchange with ArNH₂ (Ar = 4-C₆H₄Me or 2,6-C₆H₄Me or 2,6-C₆H₃Prⁱ₂) to form the corresponding arylimides [Ti(NAr)(Me₃tach)Cl₂]. The Me₃tach ring in [Ti(NR)(Me₃tach)Cl₂] undergoes slow exchange with Bu^t₃tach or Me₃tacn (1,4,7-trimethyl-1,4,7-triazacyclononane) to give the ring-exchanged products [Ti(NR)(Bu^t₃tach)Cl₂] and [Ti(NR)(Me₃tacn)Cl₂], respectively. The complexes [Ti(NR)(Me₃tach)X₂] (R = Bu^t or 2,6-C₆H₃Prⁱ₂; X = Cl or CH₂Ph) exhibit room-temperature dynamic NMR behaviour via an unusual trigonal twist of the facially coordinated Me₃tach ligand, and the activation parameters for these processes have been measured and are discussed. The X-ray structures of [Ti(NR)(Bu^t₃tach)Cl₂] (R = Bu^t or 2,6-C₆H₃Prⁱ₂) and [Ti(NBu^t)(Me₃tach)(X)₂] [X= Cl or CH₂Ph) are reported. Me₃tach and Bu^t₃tach = 1,3,5-trimethyl- and tri-tert-butyl-1,3,5-triazacyclohexane, respectively.     

Silyl-substituted alkylidenes: preparation of the novel complexes and mechanistic studies of their formation from reactions of alkylidenes with silanes and silyl-to-alkylidyne migration

Alkylidene complexes (Me₃SiCH₂)₃Ta(PMe₃)=CHSiMe₃ (1) and Me₃SiCH₂Ta(PMe₃)₂(=CHSiMe₃)₂ (3a) were found to react with phenylsilanes H₂SiR′Ph (R′=Me, Ph) and (PhSiH₂)₂CH₂ to give disilyl-substituted alkylidenes (Me₃SiCH₂)₃Ta=C(SiMe₃)(SiHR′Ph) (2) and novel metallasilacyclobutadiene and metalladisilacyclohexadiene complexes. Silyl-substituted alkylidene complex (Bu^tCH₂)₂W(=O)[=C(Bu^t)(SiPh₂Bu^t)] (5a) was prepared from the reaction of O₂ with an equilibrium mixture (Bu^tCH₂)W(=CHBu^t)₂(SiPh₂Bu^t) (4b) (Bu^tCH₂)₂W(CBu^t)(SiPh₂Bu^t) (4a). Our recent studies of the preparation of these complexes and mechanistic pathways in the formation of these silyl-substituted alkylidene complexes are summarized.     

The first 2,3-dihydro-1H-[1,2,4] triphosphole

Protonation of the lithium triphospha-cyclopentenyl salt Li (P₃C₂Bu^t₂RR′) (R=(Me₃Si)₂CH-, R′=Buⁿ) with HCl affords the new 2,3-dihydro-1H-[1,2,4] triphosphole P₃C₂Bu^t₂(H) (Buⁿ)CH(SiMe₃)₂ which has been structurally characterised as its [W(CO)₅] complex.     

Synthesis of polysilanes bearing pendant carbosilyl groups and Si-NMR probe on the tacticity using side chain silicon atoms

New functional polysilanes [R₂R¹Si(CH₂)₂SiH]_n (R=Me, R¹=H (1); R=R¹=Et (2); R=Me, R¹=Ph (3)) bearing carbosilyl side chains have been synthesized by catalytic dehydropolymerization of precursor carbosilanes R₂R¹SiCH₂CH₂SiH₃ using Cp₂TiCl₂–BuLi as a catalyst. These polymers are characterized by ¹H, ¹³C, ²⁹Si, {¹H–²⁹Si} HSQC NMR spectroscopy, GPC and TGA. Attempts to delineate the tacticity from the analysis of deconvoluted ²⁹Si{¹H}-NMR signals associated with the side chain silicon atoms reveal that the triad concentration ratio follows a Bernoullian statistical model for polymers 1 and 2 only.     

Group 4 metallacarboranes of constrained geometries derived from B(cage)- and C(cage)-silylamido-substituted carborane ligands: a synthetic and structural investigation

The reactions of RNHSi(Me)₂Cl (1, R=t-Bu; 2, R=2,6-(Me₂CH)₂C₆H₃) with the carborane ligands, nido-1-Na(C₄H₈O)-2,3-(SiMe₃)₂-2,3-C₂B₄H₅ (3) and Li[closo-1-R′-1,2-C₂B₁₀H₁₀] (4), produced two kinds of neutral ligand precursors, nido-5-[Si(Me)₂N(H)R]-2,3-(SiMe₃)₂-2,3-C₂B₄H₅, (5, R=t-Bu) and closo-1-R′-2-[Si(Me)₂N(H)R]-1,2-C₂B₁₀H₁₀ (6, R=t-Bu, R′=Ph; 7, R=2,6-(Me₂CH)₂C₆H₃, R′=H), in 85, 92, and 95% yields, respectively. Treatment of closo-2-[Si(Me)₂NH(2,6-(Me₂CH)₂C₆H₃)]-1,2-C₂B₁₀H₁₁ (7) with three equivalents of freshly cut sodium metal in the presence of naphthalene produced the corresponding cage-opened sodium salt of the “carbons apart” carborane trianion, [nido-3-{Si(Me)₂N(2,6-(Me₂CH)₂C₆H₃)}-1,3-C₂B₁₀H₁₁]³⁻ (8) in almost quantitative yield. The reaction of the trianion, 8, with anhydrous MCl₄ (M=Ti and Zr) in 1:1 molar ratio in dry tetrahydrofuran (THF) at −78 °C, resulted in the formation of the corresponding half-sandwich neutral d⁰-metallacarborane, closo-1-M[(Cl)(THF)_n]-2-[1′-η¹σ-N(2,6-(Me₂CH)₂C₆H₃)(Me)₂Si]-2,4-η⁶-C₂B₁₀H₁₁ (M=Ti (9), n=0; M=Zr (10), n=1) in 47 and 36% yields, respectively. All compounds were characterized by elemental analysis, ¹H-, ¹¹B-, and ¹³C-NMR spectra and IR spectra. The carborane ligand, 7, was also characterized by single crystal X-ray diffraction. Compound 7 crystallizes in the monoclinic space group P2₁/c with a=8.2357(19) Å, b=28.686(7) Å, c=9.921(2) Å; β=93.482(4)°; V=2339.5(9) ų, and Z=4. The final refinements of 7 converged at R=0.0736; wR=0.1494; GOF=1.372 for observed reflections.     

Synthesis, structure and nuclease activity of copper complexes of disubstituted 2,2′-bipyridine ligands bearing ammonium groups

A series of Cu(II) complexes of disubstituted 2,2′-bipyridine bearing ammonium groups [Cu(L¹⁻⁴)₂Br]⁵⁺ (1–4, L¹ = [5,5′-(Me₂NHCH₂)₂-bpy]²⁺, L² = [5,5′-(Me₃NCH₂)₂-bpy]²⁺, L³ = [4,4′-(Me₂NHCH₂)₂-bpy]²⁺, L⁴ = [4,4′-(Me₃NCH₂)₂-bpy]²⁺ and bpy = 2,2′-bipyridyl) were synthesized, of which complexes 1 and 4 were structurally characterized. Both coordination configurations of Cu(II) ions can be described as distorted trigonal bipyramid. The interaction between all complexes and CT-DNA was evaluated by thermal-denaturation experiments and CD spectroscopy. Results show that the complexes interact with CT-DNA via outside electrostatic interactions and their binding ability follows the order: 1 > 2 > 3 > 4. In the absence of any reducing agents, the cleavage of plasmid pBR322 DNA by these complexes was investigated and the hydrolysis kinetics of DNA was studied in Tris buffer (pH 7.5) at 37 °C. Obtained pseudo-Michaelis–Menten kinetic parameters: 15.0, 13.6, 2.01 and 1.69 h⁻¹ for 1, 2, 3 and 4, respectively, indicate that complexes 1 and 2 exhibit very high DNA cleavage activities. According to their crystal data, the high nuclease activity may be attributed to the strong interaction of the metal moiety and two ammonium groups with phosphate groups of DNA.     

Syntheses, X-ray structures, and reactions of ruthenium carbonyl complexes containing 1,1-dithiolates

Treatment of [Ru₂(CO)₄(MeCN)₆][BF₄]₂ or [Ru₂(CO)₄(μ-O₂CMe)₂(MeCN)₂] with uni-negative 1,1-dithiolate anions via potassium dimethyldithiocarbamate, sodium diethyldithiocarbamate, potassium tert-butylthioxanthate, and ammonium O,O′-diethylthiophosphate gives both monomeric and dimeric products of cis-[Ru(CO)₂(η²-(SS))₂] ((SS)⁻=Me₂NCS₂⁻ (1), Et₂NCS₂⁻ (2), ^tBuSCS₂⁻ (3), (EtO)₂PS₂⁻ (4)) and [Ru(CO)(η²-(Me₂NCS₂))(μ,η²-Me₂NCS₂)]₂ (5). The lightly stabilized MeCN ligands of [Ru₂(CO)₄(MeCN)₆][BF₄]₂ are replaced more readily than the bound acetate ligands of [Ru₂(CO)₄(μ-O₂CMe)₂(MeCN)₂] by thiolates to produce cis-[Ru(CO)₂(η²-(SS))₂] with less selectivity. Structures 1 and 5 were determined by X-ray crystallography. Although the two chelating dithiolates are cis to each other in 1, the dithiolates are trans to each other in each of the {Ru(CO)(η²-Me₂NCS₂)₂} fragment of 5. The dimeric product 5 can be prepared alternatively from the decarbonylation reaction of 1 with a suitable amount of Me₃NO in MeCN. However, the dimer [Ru(CO)(η²-Et₂NCS₂)(μ,η²-Et₂NCS₂)]₂ (6), prepared from the reaction of 2 with Me₃NO, has a structure different from 5. The spectral data of 6 probably indicate that the two chelating dithiolates are cis to each other in one {Ru(CO)(η²-Et₂NCS₂)₂}fragment but trans in the other. Both 5 and 6 react readily at ambient temperature with benzyl isocyanide to yield cis-[Ru(CO)(CNCH₂Ph)(η²-(SS))₂] ((SS)=Me₂NCS₂⁻ (7) and Et₂NCS₂⁻ (8)). A dimerization pathway for cis-[Ru(CO)₂(η²-(SS))₂] via decabonylation and isomerization is proposed.     

Zur thermolyse von silyltriazenen

Whilst mono(silyl)triazenes R′N=N---NR′(SiR₃) and organyl triazenes R′N=N---NR′₂ are of comparable thermal stability and decay by a radical reaction, bis(silyl)triazenes R′N=N---N(SiR₃)₂ (R′=aryl, R=Me, Et, OMe) decompose at room temperature in a non-radical reaction to yield amines R′N(SiR₃)₂ and nitrogen. Kinetic investigations of the mechanism of the non-radical thermolysis of triazenes show that the rate of the thermolysis of R′N=N---N(SiR₃)₂ is determined both from an isomerisation equilibrium forming (R₃Si)R′N---N=N(SiR₃) and from the rate of decomposition of this compound to the thermolysis products. Tris(silyl)triazenes, (R₃Si)₂N---N=N(SiR₃), hitherto not synthesized, are expected to be even more unstable than the bis(silyl)triazenes which have been examined by us.     

Substituted metal carbonyls XIII. Fe(CO)4(η-dppf) [where DPPF = (Ph2PC5H4)2Fe]: a convenient building block for heterometallic complexes

The potential of Fe(CO)₄(η¹-dppf) (dppf = 1,1′-bis(diphenylphosphino)ferrocene) as a precursor for heterometallic species is fully expanded in the synthesis of (OC)₄Fe(μ-dppf)Cr(CO)₅, (OC)₄Fe(μ-dppf)W(CO)₅, and (OC)₄Fe(μ-dppf)Mn₂(CO)₉, all of which have been characterized by IR, NMR (¹H and ³¹P) and elemental analyses. The low energy requirement of TMNO (Me₃NO · 2H₂O)decarbonylation allows the formation of monosubstituted Mn₂(CO)₁₀ as the major product. This aspect is further substantiated by the isolation of Mn₄(CO)₁₈(μ-dppf) in which the single bridging of a diphosphine group between two Mn₂(CO)₉ moieties is unprecedented.     

N,N′-bis(substituted-phenyl)oxamides and their dinuclear pentacoordinate nickel(II) complexes

The preparation, spectroscopic characterization and magnetic study of N,N′-bis(substituted-phenyl)oxamidate-bridged nickel(II) dinuclear complexes of formula {[Ni(N₃-mc)]₂(μ-CONC₆H₄-X)}(PF₆)₂ (N₃-mc = 2,4,4-trimethyl-1,5,9-triazacyclo-dodec-1-ene (Me₃-N₃-mc) or 2,4,4,9-tetramethyl-1,5,9-triazacyclododec-1-ene (Me₄-N₃-mc), X = 2-Cl, 4-Cl, 2-OCH₃, 4-OCH₃) are reported. These paramagnetic nickel(II) complexes have been characterized by both one- and two-dimensional (COSY) ¹H NMR techniques. The COSY spectrum of 5 has allowed to achieve the assignment of the phenyl protons of the N,N′-diphenyloxamidate. The crystal structures of [Ni(Me₃-N₃-mc)(μ-CONC₆H₄-4-Cl)]₂(PF₆)₂ (6), [Ni(Me₃-N₃-mc)(μ-CONC₆H₄-4-OMe)]₂(PF₆)₂ (8) and [Ni(Me₄-N₃-mc)(μ-CONC₆H₄-2-Cl)]₂(PF₆)₂ (9) have been determined and their magnetic properties have been studied. The value of magnetic coupling between the two nickel(II) ions across the oxamidate bridge [J = − 37.6 (6), −39.9 (8) and −39.7 cm⁻¹ (9)] is sensitive to the distortion of the coordination sphere of the metal ions and the topology of the molecular bridge.     

Mono- und dicarbenkomplexe durch reaktion von pentacarbonyleisen mit einigen dialkylamiden des zwei- und vierwertigen zinns

The dialkylamides of tin react with ironpentacarbonyl to form carbene complexes. With Me₂Sn(NMe₂)₂ and Sn(NMe₂)₄ yellow dicarbene complexes are formed by addition of two Sn---N bonds to adjacent carbonyl groups. The two carbenoid systems on the central atom are parts of a chelate ligand connected by an ---O---Sn---O--- bridge. Using [Sn(NMe₂)₂]₂, a red monomeric compound (CO)₃Fe(CONMe₂)₂Sn containing the same cyclic structural unit can be isolated. The free activation enthalpy of rotation about the C(carbene)---N bond in the tin (IV) dicarbene complexes was found to be 16.5 kcal mol^-1.     

Übergangsmetall-silyl-komplexe L. darstellung, struktur und reaktivität der Trihydrido-Silyl-und -Stannyl-Komplexe L3FeH3(ER3) (E =Si,

Photochemical reaction of (CO)₂(dppe)Fe(H)(SiR₃) with HSiR₃ (SiR₃ = Si(OMe)₃, Si(OEt)₃, SiMe₃, SiMe₂Ph, SiPh₃) yields the trihydrido silyl complexes (CO)(dppe)FeH₃(SiR₃ ). The analogous complexes (PR′Ph₂)₃ FeH₃(ER₃) are prepared by reaction of the H₂ -complexes (PR′Ph₂)₃FeH₂(H₂) with HER₃ (ER₃ = SiMe₃, SiMC₂Ph, SiMePh₂, SiPh₃, Si(Me₂)OSi(Me₂)H, SnPh₃, SnEt₃). Additional derivates of (CO) (dppe)FeH₃(SiR₃) (SiR₃ = SiMePh₂) and (PR′Ph₂)₃FeH₃(SiR₃) (SiR₃ = Si(OMe)₃, SiH₂Ph, SiHPh₂, Si(OEt)₃, SiMePhCl) are accessible by silane exchange starting from (CO)(dppe)FeH₃(SiMe₃) and (PR′Ph₂) ₃FeH₃(SiMe₃). (PBuPh₂)₃FeH₃(SiMePh₂) was also prepared from (PBuPh₂)₃FeH₂(N₂) and HSiMePh₂, and (PBuPh₂)₃FeH₃(SnMe₃) from (PBuPh₂)₃FeH₂(H₂) and Me₃SnCl. The complex (PBuPh₂) ₃FeH₃(SnMe₃) crystallizes as a toluene solvate in the cubic space group I 3d and shows crystallographically imposed C₃-symmetry. The complexes (CO)₂ (dppe)Fe(H)(SiR₃) and (PR′Ph₂)₃FeH₃(ER₃) are highly dynamic in solution. Low temperature NMR measurements and the E, Fe, H coupling constants strongly indicate that the exchange mechanism involves η²-HER₃ ligands.     

Syntheses and crystal structures of lithium derivatives of diphosphanes R2P–P(SiMe3)Li · 3L, R = Ph, Pr and Pr2N, L = THF or DME

The reactions of R₂P–P(SiMe₃)₂ (R = Ph, ⁱPr and ⁱPr₂N) with BuLi in THF or DME solution lead to ion-contacted lithium derivatives R₂P–P(SiMe₃)Li · 3THF (R = ⁱPr, ⁱPr₂N) with tetrahedrally surrounded Li atoms and to the solvent-separated ionic [Li · 3DME]⁺[Ph₂P–PSiMe₃]⁻ with an octahedrally surrounded Li atom as confirmed by X-ray crystal structure analysis. The reaction of BuLi with Ph₂P–P(SiMe₃)₂ is accompanied with a significant side-reaction leading to Ph₂P–PPh₂ and to LiP(SiMe₃)₂.     

A new structural type of liquid crystal Crystal structures and thermotropic mesophases of dihydroxytetraalkyldisiloxanes: Columnar phases with hydrogen bonded assemblies

Previous structural investigations of mesogenic organosilicon compounds (1, 3-dihydroxytetraalkyldisiloxanes, [R₂(OH)Si]₂O, R = C_nH_2n+1) which form thermotropic phases are outlined. The crystal and molecular structure determination of a non-mesogenic member of this series [Me₂(OH)Si]₂O is described. It is inferred that the mesophases formed by this family of compounds belong to a new structural type with columnar stacks of the molecules laced together with hydrogen bonds.     

Über dimere dimethylmetall-bis(trimethylgermyl)amide des aluminiums, galliums und indiums

The dimethylmetal bis(trimethylgermyl)amides of Al, Ga, and In have been prepared from Li[N(GeMe₃)₂] and Me₂MCl (Me = CH₃, M = Al, Ga) or Me₂MCN (M = Ga, In) in inert solvents. The NMR (¹H, ¹³C) and vibrational spectra (IR and Raman) of these dimeric compounds have been assigned and discussed. According to the X-ray structure determination [Me₂InN(GeMe₃)₂]₂ crystallizes in the monoclinic space group C2/c (Z = 4, R = 0.032) and is isomorphous with the bis(trimethylsilyl) homologue.     

Reactions of stereochemically rigid diisocyanides with manganese carbonyl derivatives

The reactions of BrMn(CO)₅ with the non-chelating stereochemically rigid bidentate ligands (L-L) 1,3-, and 1,4-diisocyanobenzene, 4,4′-diisocyanobiphenyl, and 4,4′-diisocyanodiphenylmethane afford well characterized complexes of the types BrMn(CO)₄(L-L), BrMn(CO)₃(L-L)₂, and [BrMn(CO)₄]₂(L-L). Similar reactions with [RC₅H₄Mn(CO)₂NO]⁺PF₆⁻ gave mixtures of oligomers of the type [(RC₅H₄MnNO)_n(L-L)_n+1]ⁿ⁺[PF₆⁻]_n.