Hypervalent organobismuth(iii) carbonate, chalcogenides and halides with the pendant arm ligands 2-(Me2NCH2)C6H4 and 2,6-(Me2NCH2)2C6H3

R2BiOH (1) [R = 2-(Me2NCH2)C6H4] and (R2Bi)2O (2) are formed by hydrolysis of R2BiCl with KOH. Single crystals of were obtained by air oxidation of (R2Bi)2. The reaction of R2BiCl and Na2CO3 leads to (R2Bi)2CO3 (3). 3 is also formed by the absorption of CO2 from the air in solutions of 1 or 2 in diethyl ether or toluene. (R2Bi)2S (4) is obtained from R2BiCl and Na2S or from (R2Bi)2 and S8. Exchange reactions between R2BiCl and KBr or NaI give R2BiX [X = Br (5), I (6)]. The reaction of RBiCl2 (7) with Na2S and [W(CO)5(THF)] gives cyclo-(RBiS)2[W(CO)5]2 (8). cyclo-(R'BiS)2 (9) [R' = 2,6-(Me2NCH2)2C6H3] is formed by reaction of R'BiCl2 and Na2S. The structures of were determined by single-crystal X-ray diffraction.     

Isomers of a dibismuthane, R2Bi-BiR2 [R = 2,6-(Me2NCH2)2C6H3], and unusual reactions with oxygen: formation of [R2Bi]2(O2) and R'R' 'Bi [R' = 2-(Me2NCH2)-6-{Me2N(O)CH2}C6H3; R' ' = 2-(Me2NCH2)-6-{O(O)C}C6H3

R2Bi-BiR2 [1; R = 2,6-(Me2NCH2)2C6H3], a dibismuthane that exists in different forms in the crystalline state, reacts in air with the formation of the peroxide [R(2)Bi]2(O2) (2) and partial oxidation of the pendant (dimethylamino)methyl groups, yielding the mononuclear bismuth complex R'R' 'Bi (3) [R' = 2-(Me2NCH2)-6-{Me2N(O)CH2}C6H3; R' ' = 2-(Me2NCH2)-6-{O(O)C}C6H3].     

Characterization of the sterically encumbered terphenyl-substituted species 2,6-Trip2H3C6Sn-Sn(Me)2C6H3-2,6-Trip2, an unsymmetric, group 14 element, methylmethylene, valence isomer of an alkene, its related lithium derivative 2,6-Trip2H3C6(Me)2Sn-Sn(Li)(Me)C6H3-2,6-Trip2, and the monomer Sn(t-Bu)C6H3-2,6-Trip2 (Trip = C6H2-2,4,6-i-Pr3)

The reaction of the recently reported sterically encumbered terphenyl tin(II) halide species Sn(Cl)C6H3-2,6-Trip2 (Trip = C6H2-2,4,6-i-Pr3), 1, with 1 equiv of MeLi or MeMgBr afforded 2,6-Trip2H3C6Sn-Sn(Me)2C6H3-2,6-Trip2, 2, which is the first stable group 14 element methylmethylene (i.e., CH3CH) analogue of ethylene (H2CCH2). Reaction of 1 with 1.5 equiv of MeLi yielded the stannylstannate species 2,6-Trip2H3C6(Me)2Sn-Sn(Li)(Me)-C6H3-2,6-Trip2, 3, whereas reaction of 1 with 1 equiv of t-BuLi gave the heteroleptic stannanediyl monomer Sn(t-Bu)C6H3-2,6-Trip2 (4). The compounds 2-4 were characterized by 1H, 13C (7Li, 3 only), and 119Sn NMR spectroscopy in solution and by UV-vis spectroscopy. The X-ray crystal structures of 2-4 were also determined. The formation of the stannylstannanediyl 2 instead of the expected symmetrical, valence isomer "distannene" form (Sn(Me)C6H3-2,6-Trip2)2, 6, is explained through the ready formation of LiSn(Me)2C6H3-2,6-Trip2, 5, which reacts rapidly with 1 to produce 2 which can then react with a further equivalent of MeLi to give 3. The stability of singly bonded 2 in relation to the formally doubly bonded 6 was rationalized on the basis of the difference in the strength of their tin-tin bonds. In contrast to the methyl derivatives, the reaction of 1 with t-BuLi proceeded smoothly to give the monomeric compound 4. Apparently, the formation of a t-Bu analogue of 5 was prevented by the more crowding t-Bu group. Compound 2 is also the first example of a stable molecule with bonding between a two-coordinate, bivalent tin and four-coordinate tetravalent tin. Both compounds 2 and 3 display large J 119Sn-119Sn couplings between their tin nuclei and the tin-tin bond lengths in 2 (2.8909(2) A) and 3 (2.8508(4) A) are relatively normal despite the presence of the sterically crowding terphenyl substituents.     

Crystal and Molecular Structure of [2,6‐(Me2NCH2)2C6H3]2SnF2, an Intramolecularly Coordinated Diorganotin Difluoride

Single‐crystal X‐ray diffraction analysis of [2,6‐(Me₂NCH₂)₂C₆H₃]₂SnF₂ reveals that only one of the two dimethylaminomethyl groups of each pincer‐type ligands [2,6‐(CH₂NMe₂)₂C₆H₃]^? is coordinated to the tin atom at Sn‐N distances of 2.576(2) and 2.470(2) Å, inducing chirality of the latter. The tin atom exhibits a distorted octahedral trans(C,C)cis(N,N)cis(F,F) configuration. Extensive intra‐ and intermolecular C‐H···F hydrogen bonding is observed with the latter giving rise to formation of polymeric chains.     

Organobismuth compounds with the pincer ligand 2,6-(Me2NCH2)2C6H3: monoorganobismuth(III) carbonate, sulfate, nitrate, and a diorganobismuthenium(III) salt

The reaction of RBiCl(2) (1) [R = 2,6-(Me(2)NCH(2))(2)C(6)H(3)] with Na(2)CO(3) or Ag(2)SO(4) (1 : 1 molar ratio) gave RBiCO(3) (2) and RBiSO(4) (3), respectively. RBi(NO(3))(2) (4) was obtained from RBiCl(2) and AgNO(3) (1 : 2 molar ratio). The ionic complex [R(2)Bi][W(CO)(5)Cl] (6) was obtained from R(2)BiCl (5) and W(CO)(5)(THF), following an unusual chlorine transfer from bismuth to tungsten. Compounds 2-4 are partially soluble in water. The molecular structures of 2·0.5CH(2)Cl(2), 3, 4·H(2)O and 6 were established by single-crystal X-ray diffraction. The carbonate 2 and the sulfate 3 exhibit a polymeric structure based on bridging oxo anions, while for the compound 4 dimer associations are formed, with both bridging and terminal nitrate anions. Dimer associations, based on weak Cl···H interactions between the cation and the anion, were found in the crystal of 6.     

X-ray structure and dynamic behaviour in solution of N-methylthio-N'-2,6-dimethylphenyl).2,6-dimethyl-1,4-quinonediimine formed by the alcoholysis of [Me2 Al{2,6-Me2C6H3NS(Me)NC6H3Me2-2,6}]2

Reaction of [Me₂Al{RNS(Me)NR}]₂ (R = 2,6-Me₂C₆H₃) with t-BuOH affords N-methylthio-N-(2,6-dimethylphenyl)-2,6-dimethyl-1,4-quinonediimine in 67% yield. The X-ray structure of this compound shows that two conformational isomers are present in the solid. Temperature dependent ¹³C and ¹H NMR measurements show that in solution these conformers exchange at a rate which is fast on the NMR time scale at + 60°C and slow at ?₆₀°C. From the coalescence point of two of the ¹³C resonances, the free energy of activation is estimated to be 13.7 + 1.0 $\text{kcal}\text{mol}$ at 10°C. Possible processes for the exchange are discussed, and also a reaction scheme for the formation of the title compound is discussed.     

A comparative study of pi-arene-bridged lanthanum arylamide and aryloxide dimers. Solution behavior, exchange mechanisms, and X-ray crystal structures of La2(NH-2,6-iPr2C6H3)6, La(NH-2,6-iPr2C6H3)3(THF)3, and La(NH-2,6-iPr2C6H3)3(py)2

Reaction of 3 equiv of 2,6-diisopropylaniline with La[N(SiMe(3))(2)](3) produces the dimeric species La(2)(NHAr)(6) (1). X-ray crystallography reveals a centrosymmetric structure, where the dimeric unit is bridged by intermolecular eta(6)-arene interactions of a unique arylamide ligand attached to an adjacent metal center. Exposure of 1 to THF results in formation of the monomeric tris-THF adduct La(NHAr)(3)(THF)(3) (2), which was shown by X-ray crystallography to maintain a fac-octahedral structure in the solid state. (1)H NMR spectroscopy illustrates that the binding of THF to 1 to form 2 is reversible and removal of THF under vacuum regenerates dimeric 1. Addition of pyridine to 1 yields the monomeric bis-pyridine adduct La(NHAr)(3)(py)(2) (3), which exhibits a distorted trigonal-bipyramidal La metal center. Solution (1)H NMR, IR, and Raman spectroscopy indicate that the pi-arene-bridged dimeric structure of 1 is maintained in solution. Variable-temperature (1)H NMR spectroscopic investigations of 1 are consistent with a monomer-dimer equilibrium at elevated temperature. In contrast, variable-temperature (1)H NMR spectroscopic investigations of the aryloxide analogue La(2)(OAr)(6) (4) show that the bridging and terminal aryloxide groups exchange by a mechanism in which the dimeric nature of the compound is retained. Density functional theory (DFT) calculations were carried out on model compounds La(2)(OC(6)H(5))(6), La(2)(NHC(6)H(5))(6), and (C(6)H(5)R)La(XC(6)H(5))(3), where X = O or NH and R = H, OH, or NH(2). The formation of eta(6)-arene interactions is energetically favored over monomeric LaX(3) (X = OPh or NHPh) with the aryloxide pi-arene interaction being stronger than the arylamide pi-arene interaction. Calculation of vibrational frequencies reveals the origin of the observed IR spectral behavior of both La(2)(OC(6)H(5))(6) and La(2)(NHC(6)H(5))(6), with the higher energy nu(C=C) stretch due to terminal ligands and the lower energy stretch associated with the bridging ligands.     

Syntheses and chemistry of hypervalent cyclo-R4Sb4, cyclo-(RSbE)n[R = 2-(Me2NCH2)C6H4, E = O, S] and precursors

The cyclostibane R(4)Sb(4)(1)(R = 2-(Me(2)NCH(2))C(6)H(4)) was synthesized by reduction of RSbCl(2) with Mg in THF or with Na in liquid NH(3). The reaction of 1 with [W(CO)(5)(THF)] gives the stibinidene complex RSb[W(CO)(5)](2)(2). RSbCl(2) and (RSbCl)(2)E [E = O (6), E = S (8)] react with KOH or Na(2)S in toluene/water to give the heterocycles (RSbE)(n)[E = O, n= 3 (3); E = S, n= 2 (4)]. The chalcogeno-bridged compounds of the type (RSbCl)(2)E [E = O (6), E = S (8)] were synthesized by reaction of RSbCl(2) with KOH or Na(2)S in toluene/water, but also by reaction of RSbCl(2) with the heterocycles (RSbE)(n). The compounds (RSbI)(2)O (7) and (RSbBr)(2)S (9) were prepared via halogen-exchange reactions between (RSbCl)(2)E and NaI (E = O) or KBr (E = S) or by reactions between RSbI(2) and KOH or RSbBr(2) and Na(2)S. The reaction of cyclo-(RSbS)(2) with W(CO)(5)(THF) in THF results in trapping of the cis isomer in cyclo-(RSbS)(2)[W(CO)(5)](5). The solution behaviour of the compounds was investigated by (1)H and (13)C NMR spectroscopy. The molecular structures of compounds 1-7 and 9 were determined by single-crystal X-ray diffraction.     

Synthesis, structural characterization, and spectroscopy of the cadmium-cadmium bonded molecular species Ar'CdCdAr' (Ar' = C6H3-2,6-(C6H3-2,6-Pri2)2)

The synthesis and first structural characterization of a cadmium-cadmium bonded molecular compound Ar'CdCdAr' (Ar' = C6H3-2,6-(C6H3-2,6-Pri2)2) are reported. The existence of the Cd-Cd bond was established by 113Cd NMR spectroscopy and X-ray diffraction (Cd-Cd = 2.6257(5) A). Like its group 12 analogue Ar'ZnZnAr', DFT calculations showed that Ar'CdCdAr' had significant p-character in the Cd-Cd sigma-bonding HOMO.     

Fluorine for hydrogen exchange in the hydrofluorobenzene derivatives C6H(x)F(6-x), where x = 2, 3, 4 and 5 by monomeric [1,2,4-(Me3C)3C5H2]2CeH: the solid state isomerization of [1,2,4-(Me3C)3C5H2]2Ce(2,3,4,5-C6HF4) to [1,2,4-(Me3C)3C5H2]2Ce(2,3,4,6-C6HF4)

The reaction between monomeric bis(1,2,4-tri-tert-butylcyclopentadienyl)cerium hydride, Cp'2CeH, and several hydrofluorobenzene derivatives is described. The aryl derivatives that are the primary products, Cp'2Ce(C6H(5-x)F(x)) where x = 1,2,3,4, are thermally stable enough to be isolated in only two cases, since all of them decompose at different rates to Cp'2CeF and a fluorobenzyne; the latter is trapped by either solvent when C6D6 is used or by a Cp'H ring when C6D12 is the solvent. The trapped products are identified by GC/MS analysis after hydrolysis. The aryl derivatives are generated cleanly by reaction of the metallacycle, Cp'((Me3C)2C5H2C(Me2)CH2)Ce, with a hydrofluorobenzene, and the resulting arylcerium products, in each case, are identified by their (1)H and (19)F NMR spectra at 20 degrees C. The stereochemical principle that evolves from these studies is that the thermodynamic isomer is the one in which the CeC bond is flanked by two ortho-CF bonds. This orientation is suggested to arise from the negative charge that is localized on the ipso-carbon atom due to C(o)(delta+)F(o)(delta-) polarization. The preferred regioisomer is determined by thermodynamic rather than kinetic effects; this is illustrated by the quantitative, irreversible solid-state conversion at 25 degrees C over two months of Cp'2Ce(2,3,4,5-C6HF4) to Cp'2Ce(2,3,4,6-C6HF4), an isomerization that involves a CeC(ipso) for C(ortho)F site exchange.     

Monocarbaborane anion chemistry. An interesting encapsulation of the Pd2I2(P(C6H(4)-4-Me)3)4]2+ cation by a pair of [PhCB9H4I(C6H4Me)4]- anions

Reaction of the [1-Ph-closo-1-CB9H(4)-6,7,8,9,10-I5]- anion with 4-MeC6H4MgBr in the presence of [PdCl2(PPh3)2] gives the [Pd2I2(P(C6H(4)-4-Me)3)4]2+ salt of the [1-Ph-closo-1-CB9H(4)-10-I-6,7,8,9-(C6H(4)-4-Me)4]- anion, which exhibits an unusual neutral supramolecular assembly in the solid state, in which the dipalladium dication is encapsulated by two four-armed 'tetrapus' anionic units; the anion also has potentialities for four-fold dendrimer construction.     

Synthesis and Structure of Triphenylbismuth Dicarboxylates Ph3Bi[OC(O)R]2 (R = CH2C6H4F-3, C6H3F2-2,3, C6HF4-2,3,4,5)

Russian Journal of General Chemistry - Bismuth compounds Ph3Bi[OC(O)R]2 (R = CH2C6H4F-3, C6H3F2-2,3, C6HF4-2,3,4,5) were synthesized by the reaction of triphenylbismuth with a carboxylic acid and...     

Synthesis and reactivity of Ir(I) and Ir(III) complexes with MeNH2, Me2C=NR (R = H, Me), C,N-C6H4{C(Me)=N(Me)}-2, and N,N'-RN=C(Me)CH2C(Me2)NHR (R = H, Me) ligands

Complexes [Ir(Cp*)Cl(n)(NH2Me)(3-n)]X(m) (n = 2, m = 0 (1), n = 1, m = 1, X = Cl (2a), n = 0, m = 2, X = OTf (3)) are obtained by reacting [Ir(Cp*)Cl(mu-Cl)]2 with MeNH2 (1:2 or 1:8) or with [Ag(NH2Me)2]OTf (1:4), respectively. Complex 2b (n = 1, m = 1, X = ClO 4) is obtained from 2a and NaClO4 x H2O. The reaction of 3 with MeC(O)Ph at 80 degrees C gives [Ir(Cp*){C,N-C6H4{C(Me)=N(Me)}-2}(NH2Me)]OTf (4), which in turn reacts with RNC to give [Ir(Cp*){C,N-C6H4{C(Me)=N(Me)}-2}(CNR)]OTf (R = (t)Bu (5), Xy (6)). [Ir(mu-Cl)(COD)]2 reacts with [Ag{N(R)=CMe2}2]X (1:2) to give [Ir{N(R)=CMe2}2(COD)]X (R = H, X = ClO4 (7); R = Me, X = OTf (8)). Complexes [Ir(CO)2(NH=CMe2)2]ClO4 (9) and [IrCl{N(R)=CMe2}(COD)] (R = H (10), Me (11)) are obtained from the appropriate [Ir{N(R)=CMe2}2(COD)]X and CO or Me4NCl, respectively. [Ir(Cp*)Cl(mu-Cl)]2 reacts with [Au(NH=CMe2)(PPh3)]ClO4 (1:2) to give [Ir(Cp*)(mu-Cl)(NH=CMe2)]2(ClO4)2 (12) which in turn reacts with PPh 3 or Me4NCl (1:2) to give [Ir(Cp*)Cl(NH=CMe2)(PPh3)]ClO4 (13) or [Ir(Cp*)Cl2(NH=CMe2)] (14), respectively. Complex 14 hydrolyzes in a CH2Cl2/Et2O solution to give [Ir(Cp*)Cl2(NH3)] (15). The reaction of [Ir(Cp*)Cl(mu-Cl)]2 with [Ag(NH=CMe2)2]ClO4 (1:4) gives [Ir(Cp*)(NH=CMe2)3](ClO4)2 (16a), which reacts with PPNCl (PPN = Ph3=P=N=PPh3) under different reaction conditions to give [Ir(Cp*)(NH=CMe2)3]XY (X = Cl, Y = ClO4 (16b); X = Y = Cl (16c)). Equimolar amounts of 14 and 16a react to give [Ir(Cp*)Cl(NH=CMe2)2]ClO4 (17), which in turn reacts with PPNCl to give [Ir(Cp*)Cl(H-imam)]Cl (R-imam = N,N'-N(R)=C(Me)CH2C(Me)2NHR (18a)]. Complexes [Ir(Cp*)Cl(R-imam)]ClO4 (R = H (18b), Me (19)) are obtained from 18a and AgClO4 or by refluxing 2b in acetone for 7 h, respectively. They react with AgClO4 and the appropriate neutral ligand or with [Ag(NH=CMe2)2]ClO4 to give [Ir(Cp*)(R-imam)L](ClO4)2 (R = H, L = (t)BuNC (20), XyNC (21); R = Me, L = MeCN (22)) or [Ir(Cp*)(H-imam)(NH=CMe2)](ClO4)2 (23a), respectively. The later reacts with PPNCl to give [Ir(Cp*)(H-imam)(NH=CMe2)]Cl(ClO4) (23b). The reaction of 22 with XyNC gives [Ir(Cp*)(Me-imam)(CNXy)](ClO4)2 (24). The structures of complexes 15, 16c and 18b have been solved by X-ray diffraction methods.