Formation and structural characterization of mercury complexes from Te(R)CH2SiMe3 (R = Ph, CH2SiMe3) and HgCl2

The reaction of HgCl₂ and Te(R)CH₂SiMe₃ [R = CH₂SiMe₃ (1), Ph (2)] in ethanol yielded a mononuclear complex [HgCl₂{Te(R)CH₂SiMe₃}₂] (R = Ph, 3a; R = CH₂SiMe₃, 3b). The recrystallization of 3a or 3b from CH₂Cl₂ produced a dinuclear complex [Hg₂Cl₂(μ-Cl)₂{Te(R)CH₂SiMe₃}₂] (R = Ph, 4a; R = CH₂SiMe₃, 4b). When 3a was dissolved in CH₂Cl₂, the solvent quickly removed, and the solid recrystallized from EtOH, a stable ionic [HgCl{Te(Ph)CH₂SiMe₃}₃]Cl·2EtOH (5a·2EtOH) was obtained. Crystals of [HgCl₂{Te(CH₂SiMe)₂}]·2HgCl₂·CH₂Cl₂ (6b·2HgCl₂·CH₂Cl₂) were obtained from the CH₂Cl₂ solution of 3b upon prolonged standing. The complex formation was monitored by ¹²⁵Te-, and ¹⁹⁹Hg NMR spectroscopy, and the crystal structures of the complexes were determined by single crystal X-ray crystallography.     

The reaction of the group-13 alkyls ER3 (E = Al, Ga, In; R = CH2t-Bu, CH2 SiMe3) with the platinum-complex [(dcpe)Pt(H)(CH2t-Bu)]

The reactions of the sterically demanding group-13 alkyls ER₃ (E = Al, Ga, In; R = CH₂t-Bu, CH₂SiMe₃) with the platinum-complex [(dcpe)Pt(H)(CH₂t-Bu)] were re-investigated. The bimetallic compounds [(dcpe)Pt(ER₂)(R)] (3: E = Ga, R = CH₂SiMe₃; 5: E = In, R = CH₂t-Bu; dcpe = bis(dicyclohexylphosphino)ethane) with direct σ(Pt-E) bonds were obtained by oxidative addition of an E-C bond to the coordinatively unsaturated fragment [(dcpe)Pt] produced in situ by thermolysis of the starting complex [(dcpe)Pt(CH₂t-Bu)(H)]. The single crystal structure determination reveals a Pt-Ga bond length of 2.376(2) Å and a Pt-In bond length of 2.608(1) Å. All new compounds were characterised by elemental analysis, ³¹P and ¹⁹⁵Pt NMR spectroscopy. Interestingly, the Pt-Ga compound 3 slowly transforms into the platinum alkyl/hydride isomer {(dcpe)Pt(μ₂-H)[CH₂Si(CH₃)₂ CH₂Ga(CH₂SiMe₃)₂]} (4) during crystallization from solution at room temperature. The X-ray single crystal structure analysis revealed both complexes 3 and 4 coexisting in the unit cell in a 1:1 relation. The inaccessibility of analytically pure samples of the Pt-Al complex {(dcpe)Pt[Al(CH₂t-Bu)₂](CH₂t-Bu)} (6), postulated as intermediate of the reaction of [(dcpe)Pt(H)(CH₂t-Bu)] with Al(CH₂t-Bu) on the basis of ³¹P and ¹⁹⁵Pt NMR data, is attributed to an enhanced tendency to isomerisation into the alkyl/hydride Pt/Al congener of 4. A brief DFT analysis of the bonding situation of the model complex [(dhpe)Pt(GaMe₂)(Me)] (1M) revealed, that the contribution of π(Pt-Ga) back-bonding is negligible.     

Some complexes containing carbon chains end-capped by M(CO)2Tp′ [M = Mo, W; Tp′ = HB(pz)3, HB(dmpz)3] groups

Complexes M(CCCSiMe₃)(CO)₂Tp′ (Tp′ = Tp [HB(pz)₃], M = Mo 2, W 4; Tp′ = Tp^∗ [HB(dmpz)₃], M = Mo 3) are obtained from M(CCCSiMe₃)(O₂CCF₃)(CO)₂(tmeda) (1) and K[Tp′].Reactions of 2 or 4 with AuCl(PPh₃)/K₂CO₃ in MeOH afforded M{CCCAu(PPh₃)}(CO)₂Tp′ (M = Mo 5, W 6) containing C₃ chains linking the Group 6 metal and gold centres.In turn, the gold complexes react with Co₃(μ₃-CBr)(μ-dppm)(CO)₇ to give the C₄-bridged {Tp(OC)₂M}CCCC{Co₃(μ-dppm)(CO)₇} (M = Mo 7, W 8), while Mo(CBr)(CO)₂Tp^∗ and Co₃{μ₃-C(CC)₂Au(PPh₃)}(μ-dppm)(CO)₇ give {Tp^∗(OC)₂Mo}C(CC)₂C{Co₃(μ-dppm)(CO)₇} (9) via a phosphine-gold(I) halide elimination reaction. The C₃ complexes Tp′(OC)₂MCCCRu(dppe)Cp^∗ (Tp′ = Tp, M = Mo 10, W 11; Tp′ = Tp^∗, M = Mo 12) were obtained from 2-4 and RuCl(dppe)Cp^∗ via KF-induced metalla-desilylation reactions. Reactions between Mo(CBr)(CO)₂Tp^∗ and Ru{(CC)_nAu(PPh₃)}(dppe)Cp^∗ (n = 2, 3) afforded {Tp^∗(OC)₂Mo}C(CC)_n{Ru(dppe)Cp^∗} (n = 2 13, 3 14), containing C₅ and C₇ chains, respectively. Single-crystal X-ray structure determinations of 1, 2, 7, 8, 9 and 12 are reported.     

Synthesis and coordinating properties of the facultative Sb2O- and As2O-donor ligands O{(CH2)2ER2}2 (E = Sb or As; R = Ph or Me)

The new mixed Sb₂O-donor ligands O{(CH₂)₂SbR₂}₂ (R = Ph, 1; R = Me, 2) with flexible backbones have been prepared in good yields as air-sensitive oils from reaction of NaSbR₂ with 0.5 mol equivalents of O(CH₂CH₂Br)₂ in thf solution. The As₂O-donor analogues, O{(CH₂)₂AsR₂}₂ (R = Ph, 3; R = Me, 4) were obtained similarly from LiAsPh₂ or NaAsMe₂, respectively and O(CH₂CH₂Br)₂, although ligand 4 appears to be considerably less stable with respect to C-O bond fission under some conditions than the other ligands. Using O(CH₂CH₂Cl)₂ leads only to partial substitution by the SbPh₂⁻ or AsPh₂⁻ nucleophile. These ligands behave as bidentate chelating Sb₂- or As₂-donors in the distorted tetrahedral [M(L-L)₂]BF₄ (M = Cu or Ag; L-L = 1-4) on the basis of solution ¹H and ⁶³Cu NMR spectroscopic studies, mass spectrometry and microanalyses. Crystal structures of three representative examples with Cu(I) and Ag(I) confirm the distorted tetrahedral Sb₄ or As₄ coordination at the metal and allow comparisons of geometric parameters. The crystallographic identification of an unexpected Cu(I)-Cu(I) complex, [Cu₂{Me₂As(CH₂)₂OH}₃](BF₄)₂, obtained as a by-product via C-O bond fission within ligand 4 is also reported. The distorted octahedral [RhCl₂(L-L)₂]Cl and the distorted square planar cis-[PtCl₂(L-L)] (L-L = 1 or 2) are also described. The ether O atoms are not involved in coordination to the metal ion in any of the late transition metal complexes isolated.     

On the reactions of the tetraindium cluster In4[C(SiMe3)3]4: Insertion of the monomeric fragments InC(SiMe3)3 into chalcogen-chalcogen bonds

Treatment of the tetraindium cluster In₄[C(SiMe₃)₃]₄ (1) with diaryl dichalcogenides Aryl-E-E-Aryl (E = S, Se and Te) afforded the corresponding RIn(E-Aryl)₂ [R = C(SiMe₃)₃] compounds by insertion of the monomeric fragments InR into the chalcogen-chalcogen bonds. The dimeric formula units adopt different conformations in the solid state (C_i vs. C_2 h).     

Backbone modified small bite-angle diphosphines: Synthesis and molecular structures of [M(CO)4{X2PC(RR)PX2}] (M = Mo, W; X = Ph, Cy; R = H, Me, Et, Pr, allyl, R = Me, allyl)

A range of new small bite-angle diphosphine complexes, [M(CO)₄{X₂PC(R¹R²)PX₂}] (M = Mo, W; X = Ph, Cy; R¹ = H, Me, Et, Pr, allyl, R² = Me, allyl), have been prepared via elaboration of the methylene backbones in [M(CO)₄(X₂PCH₂PX₂)] as a result of successive deprotonation and alkyl halide addition. When X = Ph it proved possible to replace both methylene protons but for X = Cy only one substitution proved possible. This is likely due to the electron-releasing nature of the cyclohexyl groups but may also be due to steric constraints. Attempts to prepare the bis(allyl) substituted complex [Mo(CO)₄{Ph₂PC(allyl)₂PPh₂}] were only moderately successful. The crystal structures of nine of these complexes are presented.     

Steric and electronic effects in stabilizing allyl-palladium complexes of “P-N-P” ligands, X2PN(Me)PX2 (X = OC6H5 or OC6H3Me2-2,6)

The chemistry of η³-allyl palladium complexes of the diphosphazane ligands, X₂PN(Me)PX₂ [X = OC₆H₅ (1) or OC₆H₃Me₂-2,6 (2)] has been investigated.The reactions of the phenoxy derivative, (PhO)₂PN(Me)P(OPh)₂ with [Pd(η³-1,3-R′,R″-C₃H₃)(μ-Cl)]₂ (R′ = R″ = H or Me; R′ = H, R″ = Me) give exclusively the palladium dimer, [Pd₂{μ-(PhO)₂PN(Me)P(OPh)₂}₂Cl₂] (3); however, the analogous reaction with [Pd(η³-1,3-R′,R″-C₃H₃)(μ-Cl)]₂ (R′ = R″ = Ph) gives the palladium dimer and the allyl palladium complex [Pd(η³-1,3-R′,R″-C₃H₃)(1)](PF₆) (R′ = R″ = Ph) (4). On the other hand, the 2,6-dimethylphenoxy substituted derivative 2 reacts with (allyl) palladium chloro dimers to give stable allyl palladium complexes, [Pd(η³-1,3-R′,R″-C₃H₃)(2)](PF₆) [R′ = R″ = H (5), Me (7) or Ph (8); R′ = H, R″ = Me (6)].Detailed NMR studies reveal that the complexes 6 and 7 exist as a mixture of isomers in solution; the relatively less favourable isomer, anti-[Pd(η³-1-Me-C₃H₄)(2)](PF₆) (6b) and syn/anti-[Pd(η³-1,3-Me₂-C₃H₃)(2)](PF₆) (7b) are present to the extent of 25% and 40%, respectively. This result can be explained on the basis of the steric congestion around the donor phosphorus atoms in 2. The structures of four complexes (4, 5, 7a and 8) have been determined by X-ray crystallography; only one isomer is observed in the solid state in each case.     

Synthesis and characterisation of six Fe(II or III), Co(II) or Zr(IV) complexes containing the ligand [CH(SiMe2R)P(Ph)2NSiMe3] (R = Me, NEt2) and of [Co{N(SiMe3)C(Ph)C(H)P(Ph)2NSiMe3}2]

The C,N-(trimethylsilyliminodiphenylphosphoranyl)silylmethylmetal complexes [Fe(L)₂] (3), [Co(L)₂] (4), [ZrCl₃(L)]·0.83CH₂Cl₂ (5), [Fe(L)₃] (6), [Fe(L′)₂] (7) and [Co(L′)₂] (8) have been prepared from the lithium compound Li[CH(SiMe₂R)P(Ph)₂NSiMe₃] [1a, (R = Me) {≡ Li(L)}; 1b, (R = NEt₂) {≡ Li(L′)}] and the appropriate metal chloride (or for 7, FeCl₃). From Li[N(SiMe₃)C(Ph)C(H)P(Ph)₂NSiMe₃] [≡ Li(L″)] (2), prepared in situ from Li(L) (1a) and PhCN, and CoCl₂ there was obtained bis(3-trimethylsilylimino- diphenylphosphoranyl-2-phenyl-N-trimethylsilyl-1-azaallyl-N,N′)cobalt(II) (9). These crystalline complexes 3-9 were characterised by their mass spectra, microanalyses, high spin magnetic moments (not 5) and for 5 multinuclear NMR solution spectra. The X-ray structure of 3 showed it to be a pseudotetrahedral bis(chelate), the iron atom at the spiro junction.     

Dimeric and trimeric diorganosilicon chalcogenides (PhRSiE)2,3 (E = S, Se, Te; R = Ph, Me)

Ph₂SiCl₂ and PhMeSiCl₂ react with Li₂E (E = S, Se, Te) under formation of trimeric diorganosilicon chalcogenides (PhRSiE)₃ (R = Ph: 1a-3a, R = Me: cis/trans-4a (E = S), cis/trans-5a (E = Se)). In case of E = S, Se dimeric four-membered ring compounds (PhRSiE)₂ (R = Ph: 1b-2b, R = Me: cis/trans-4b (E = S), cis/trans-5b (E = Se)) have been observed as by-products. 1a-5b have been characterized by multinuclear NMR spectroscopy (¹H, ¹³C, ²⁹Si, ⁷⁷Se, ¹²⁵Te). Four- and six-membered ring compounds differ significantly in ²⁹Si and ⁷⁷Se chemical shifts as well as in the value of ¹J_SiSe.The molecular structures of 2a, 3a and trans-5a reported in this paper are the first examples of compounds with unfused six-membered rings Si₃E₃ (E = Se, Te). The Si₃E₃ rings adopt twisted boat conformations. The crystal structure of 3a reveals an intermolecular Te-Te contact of 3.858 Å which yields a dimerization in the solid state.     

Group 12 metal aryl selenolates. Crystal and molecular structure of [2-(Et2NCH2)C6H4]2Se2 and [2-(Me2NCH2)C6H4Se]2M (M = Zn, Cd)

Diorganodiselenide [2-(Et₂NCH₂)C₆H₄]₂Se₂ (1) was obtained by hydrolysis/oxidation of the corresponding [2-(Et₂NCH₂)C₆H₄]SeLi derivative. The treatment of [2-(Et₂NCH₂)C₆H₄]₂Se₂ with elemental sodium in THF resulted in [2-(Et₂NCH₂)C₆H₄]SeNa (2). Reactions between alkali metal selenolates [2-(R₂NCH₂)C₆H₄]SeM′ (R = Me, Et; M′ = Li, Na) and MCl₂ (M = Zn, Cd) in a 2:1 molar ratio resulted in the [2-(R₂NCH₂)C₆H₄Se]₂M species [R = Me, M = Zn (3), Cd (4); R = Et, M = Zn (5), Cd (6)]. The new compounds were characterized by multinuclear NMR (¹H, ¹³C, ⁷⁷Se, ¹¹³Cd) and mass spectrometry. The crystal and molecular structures of 1, 3 and 4 revealed monomeric species stabilized by N → Se (for 1) and N → M (for 3 and 4) intramolecular interactions.     

Oxidative addition of (PhSe)2 and (FcSe)2 to zerovalent palladium and platinum trialkylphosphine complexes (Fc = ferrocenyl, [Fe(η-C5H5)(η-C5H4)])

Room temperature reaction of [Pd₂(dba)₃]/PR₃ or [Pt(C₂H₄)(PR₃)₂] (dba = dibenzylideneacetone; R = Et, Bu) with the diselenides (R′Se)₂ (R′ = Ph, Fc) yielded the oxidative addition products trans-[M(SeR′)₂(PR₃)₂] (M = Pd, Pt). These have been characterised by multinuclear NMR and UV-Vis spectroscopy, mass spectrometry, and, in the cases of trans-[Pt(SePh)₂(PR₃)₂] (R = Et, Bu) and trans-[Pt(SeFc)₂(PBu₃)₂], also by X-ray crystallography.     

Synthesis and structures of bimetallic silicon-containing imido alkylidene complexes of tungsten (R′O)2(ArN)WCH-SiR2-CHW(NAr)(OR′)2 (R = Me, Ph) and (R′O)2(ArN)WCH-SiMe2SiMe2-CHW(NAr)(OR′)2

Bimetallic alkylidene complexes of tungsten (R′O)₂(ArN)WCH-SiR₂-CHW(NAr)(OR′)₂ (R = Me (1), Ph (2)) and (R′O)₂(ArN)WCH-SiMe₂SiMe₂-CHW(NAr)(OR′)₂ (3) (Ar = ; R′ = CMe₂CF₃) have been prepared by the reactions of divinyl silicon reagents R₂Si(CHCH₂)₂ with known alkylidene compounds R′′-CHMo(NAr)(OR′)₂. (R′′ = Bu^t, PhMe₂C) Complexes 1-3 were structurally characterized. Ring opening metathesis polymerization (ROMP) of cyclooctene using compounds 1-3 as initiators led to the formation of high molecular weight polyoctenamers with predominant trans-units content in the case of 1 and 3 and predominant cis-units content in the case of 2.     

R-phenyldicarboxyl (R = H, NO2 and COOH) modular effect on Ni(II) coordination polymers incorporated with a versatile connector 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole

Based on the versatile ligand 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (3,4′-Hbpt) (1), a series of coordination compounds [Ni(3,4′-Hbpt)(ip)] (2), [Ni(3,4′-Hbpt)₂(tp)(H₂O)₂] (3), [Ni₂(3,4′-Hbpt)(5-NO₂-ip)₂(H₂O)₄] (4) and [Ni(3,4′-Hbpt)(pm)_0.5(H₂O)₃]·2H₂O (5) have been hydrothermally constructed through R-phenyldicarboxyl (R = H, NO₂ and COOH) intervention effect (ip = isophthalic anion, tp = terephthalic anion, 5-NO₂-ip = 5-NO₂-isophthalic anion, pm = pyromellitic anion). Structural analysis reveals that 3,4′-Hbpt adopts μ-N_py, N_py coordination modes in two typical conformations in these target coordination compounds. In cooperation with the auxiliary ligands benzenedicarboxylate connectors, a variety of Ni(II) coordination networks such as 2-D layer with (4, 4) topology (2) 1-D chain (3), honeycomb (4) and 2-D helical chains (5) have been assembled. Theoretical calculation based on density functional theory (DFT) for ligand (1) is also employed to explicate the stability of the different conformations. Moreover, thermal stability of these crystalline materials is explored by TG-DTG.     

Synthesis, structural characterization and reactivity of new tin bridged ansa-bis(cyclopentadiene) compounds: X-ray crystal structures of Me2Sn(C5Me4R-1)2 (R = H, SiMe3)

The organo-tin compounds, Me₂Sn(C₅H₄R-1)₂ (R = Me (1), Prⁱ (2), Bu^t (3), SiMe₃ (4)) and Me₂Sn(C₅Me₄R-1)₂ (R = H (5), SiMe₃ (6)), were prepared by the reaction of Me₂SnCl₂ with the lithium or sodium derivative of the corresponding cyclopentadiene. Compounds 1-6 have been characterized by multinuclear NMR spectroscopy (¹H, ¹³C, ¹¹⁹Sn). In addition the molecular structures of 5 and 6 were determined by single crystal X-ray diffraction studies. The transmetalation reaction of 1-6 with ZrCl₄ or [NbCl₄(THF)₂] gave the corresponding metallocene complexes in high yields.     

Synthesis,spectroscopic investigation,structural characterization and DFT calculation of the complexes [ReX2(N2COPh)(4-PhPyr)(PPh3)2] (X = Cl, Br)

The reactions of [ReX₂(η²-N₂COPh-N′,O)(PPh₃)₂] with 4-phenylpyrimidine have been performed. As a result, the two complexes [ReX₂(N₂COPh)(4-PhPyr)(PPh₃)₂] (X = Cl, Br) (4-PhPyr = 4-phenylpyrimidine), isostructural in the solid state, have been obtained. The crystal and molecular structures of ([ReCl₂(N₂COPh)(4-PhPyr)(PPh₃)₂])₂·CHCl₃ (1) and ([ReBr₂(N₂COPh)(4-PhPyr)(PPh₃)₂])₂·CHCl₃ (2) have been determined. The electronic structure of [ReCl₂(N₂COPh)(4-PhPyr)(PPh₃)₂] has been examined using the density functional theory (DFT) method. The spin-allowed electronic transitions of 1 have been calculated with the time-dependent DFT method, and the UV–Vis spectrum of [ReCl₂(N₂COPh)(4-PhPyr)(PPh₃)₂] has been discussed on this basis.     

Synthesis and characterisation of [AlMen{Si(SiMe3)3}3−n(thf)] (n = 1 or 2)

The crystalline compounds [AlMe_n{Si(SiMe₃)₃}_3−n(thf)] [n = 2 (1) or 1 (2)] were prepared from the lithium sisyl [Li{Si(SiMe₃)₃}(thf)₃] (A) and the appropriate methylaluminium chloride [AlCl_3−nMe_n] in thf. The X-ray structure of 1 is reported. Unlike A or a magnesium sisyl [Mg{Si(SiMe₃)₃}₂(thf)₂] (B), neither 1 nor 2 underwent an insertion reaction with an α-H-free nitrile.     

2D hydrogen bond networks in the crystals of [(NH4 · H2O)2][(RO)(Fc)P(S)2]2 (R = 3-(BzO)-Bz, 4-(n-Bu)-Bz, Bz = benzyl)

Herein we report on the preparation of hydrated ammonium salts of the dithiophosphonic acids (RO)(Fc)P(S)(SH) (R = derivative of benzyl) featuring [(NH₄ · H₂O)₂]²⁺ cations formed by N-H?O hydrogen bonds. Interaction of these cations with the PS₂⁻ units gives rise to unprecedented 2D networks, formed solely by hydrogen bonds. These unique networks containing two- and three centered hydrogen bonds are valuable examples of the acceptor properties of sulfur atoms.     

Novel sandwich complexes of zirconium [C9H5(SiMe3)2](C5Me4R)ZrCl2 (R = CH3, CH2CH2NMe2): Synthesis and reduction behavior

Novel half-sandwich [C₉H₅(SiMe₃)₂]ZrCl₃ (3) and sandwich [C₉H₅(SiMe₃)₂](C₅Me₄R)ZrCl₂ (R = CH₃ (1), CH₂CH₂NMe₂ (2)) complexes were prepared and characterized. The reduction of 2 by Mg in THF lead to (η⁵-C₉H₅(SiMe₃)₂)[η⁵:η²(C,N)-C₅Me₄CH₂CH₂N(Me)CH₂]ZrH (7). The structure of 7 was proved by NMR spectroscopy data. Hydrolysis of 2 resulted in the binuclear complex ([C₅Me₄CH₂CH₂NMe₂]ZrCl₂)₂O (6). The crystal structures of 1 and 6 were established by X-ray diffraction analysis.     

The photochemistry of (η-2-R-C3H4)Fe(CO)(NO)(X) (R = H or Cl; X = CO or PPh3) in room temperature solution or frozen gas matrixes

A photochemical study of allyl iron complexes of the type, (η³-2-R-C₃H₄)Fe(CO)(NO)(X) (R = H or Cl; X = CO or PPh₃) is presented. These compounds were studied in solid matrixes at 20 K, and at room temperature, by a combination of laser flash at 355 nm and steady-state photolysis. The predominant photochemical process for these compounds is loss of a CO ligand. In addition, exhaustive irradiation of (η³-2-R-C₃H₄)Fe(CO)(NO)(PPh₃) with λ_exc > 300 nm provided evidence for a haptotropic shift of the allyl group from η³ to η¹ coordination.