A. Bhatt, I. May, V. Volkovich, Melissa E. Hetherington, B. Lewin, R. Thied, N. Ertok
We report the electrochemical properties of Group 15 quaternary alkyl bistriflimide salts, which have very wide electrochemical windows (between +2.6 and −3.4 V vs. Fc+/Fc for [(Me)4As][N(SO2CF3)2]) when used as supporting electrolytes in MeCN and which can be used for the electrodeposition of very electropositive metals, including Eu, in the molten state.
{"title":"Group 15 quaternary alkyl bistriflimides: ionic liquids with potential application in electropositive metal deposition and as supporting electrolytes","authors":"A. Bhatt, I. May, V. Volkovich, Melissa E. Hetherington, B. Lewin, R. Thied, N. Ertok","doi":"10.1039/B208968H","DOIUrl":"https://doi.org/10.1039/B208968H","url":null,"abstract":"We report the electrochemical properties of Group 15 quaternary alkyl bistriflimide salts, which have very wide electrochemical windows (between +2.6 and −3.4 V vs. Fc+/Fc for [(Me)4As][N(SO2CF3)2]) when used as supporting electrolytes in MeCN and which can be used for the electrodeposition of very electropositive metals, including Eu, in the molten state.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75502744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Avilés, A. Dinis, José Orlando Gonçalves, V. Félix, M. J. Calhorda, Ângela O. Prazeres, M. Drew, H. Alves, R. Henriques, V. Gama, P. Zanello, M. Fontani
The new compound [Co(η5-C5H5)(dppf-P,P′)I]I, 1, was synthesised by the stoichiometric reaction of the Co(III) complex [Co(η5-C5H5)(CO)I2], 2, with 1,1′-bis(diphenylphosphino)ferrocene (dppf) in CH2Cl2, and was characterised by multinuclear NMR spectroscopy. Exposure to air of THF or CH2Cl2 solutions of compound 1 gave, in an unexpected way, a polymeric chain comprising bridging 1,1′-bis(oxodiphenylphosphoranyl)ferrocene (dppfO2) joining tetrahedral Co(II) units [CoI2(μ-dppfO2)]n, 3. Attempts to obtain the polymeric chain 3 by the direct reaction of dppfO2 with CoI2, in CH2Cl2, gave instead the monomeric compound [CoI2(dppfO2)], 4, in which dppfO2 is coordinated in a chelating mode. The structural characterisation of compounds 2, 3, and 4 was carried out by single crystal X-ray diffraction studies. The magnetic behaviour of [CoI2(dppfO2)] and [CoI2(μ-dppfO2)]n was studied, and the results are consistent with tetrahedral S = 3/2 CoII, possessing a 4A2 ground state, and S = 0 FeII. In these compounds, CoII negative zero field splittings were determined from an analysis of the magnetic susceptibility temperature dependence, with D/k = −13 and −14 K for CoI2(dppfO2) and [CoI2(μ-dppfO2)]n, respectively. DFT calculations were performed in order to understand the electronic structure of [Co(η5-C5H5)(dppf-P,P′)I]I, 1, as well as that of the paramagnetic specie [CoI2(dppfO2)], 4. The [CoI2(μ-dppfO2)]n chain was also analysed and found to behave very similarly to the monomeric iodine derivative 4. The calculations showed the unpaired electrons to be localized on the Co(II) centre in all these species. The rather complicated electrochemical behaviour exhibited by the dppf complex [CoIII(η5-C5H5)(dppf-P,P′)I]I and by [Co(dppfO2)I2] is discussed.
{"title":"Synthesis, X-ray structures, electrochemistry, magnetic properties, and theoretical studies of the novel monomeric [CoI2(dppfO2)] and polymeric chain [CoI2(μ-dppfO2)n]","authors":"T. Avilés, A. Dinis, José Orlando Gonçalves, V. Félix, M. J. Calhorda, Ângela O. Prazeres, M. Drew, H. Alves, R. Henriques, V. Gama, P. Zanello, M. Fontani","doi":"10.1039/B205942H","DOIUrl":"https://doi.org/10.1039/B205942H","url":null,"abstract":"The new compound [Co(η5-C5H5)(dppf-P,P′)I]I, 1, was synthesised by the stoichiometric reaction of the Co(III) complex [Co(η5-C5H5)(CO)I2], 2, with 1,1′-bis(diphenylphosphino)ferrocene (dppf) in CH2Cl2, and was characterised by multinuclear NMR spectroscopy. Exposure to air of THF or CH2Cl2 solutions of compound 1 gave, in an unexpected way, a polymeric chain comprising bridging 1,1′-bis(oxodiphenylphosphoranyl)ferrocene (dppfO2) joining tetrahedral Co(II) units [CoI2(μ-dppfO2)]n, 3. Attempts to obtain the polymeric chain 3 by the direct reaction of dppfO2 with CoI2, in CH2Cl2, gave instead the monomeric compound [CoI2(dppfO2)], 4, in which dppfO2 is coordinated in a chelating mode. The structural characterisation of compounds 2, 3, and 4 was carried out by single crystal X-ray diffraction studies. The magnetic behaviour of [CoI2(dppfO2)] and [CoI2(μ-dppfO2)]n was studied, and the results are consistent with tetrahedral S \u0000= 3/2 CoII, possessing a 4A2 ground state, and S \u0000= 0 FeII. In these compounds, CoII negative zero field splittings were determined from an analysis of the magnetic susceptibility temperature dependence, with D/k \u0000= \u0000−13 and −14 K for CoI2(dppfO2) and [CoI2(μ-dppfO2)]n, respectively. DFT calculations were performed in order to understand the electronic structure of [Co(η5-C5H5)(dppf-P,P′)I]I, 1, as well as that of the paramagnetic specie [CoI2(dppfO2)], 4. The [CoI2(μ-dppfO2)]n chain was also analysed and found to behave very similarly to the monomeric iodine derivative 4. The calculations showed the unpaired electrons to be localized on the Co(II) centre in all these species. The rather complicated electrochemical behaviour exhibited by the dppf complex [CoIII(η5-C5H5)(dppf-P,P′)I]I and by [Co(dppfO2)I2] is discussed.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80278798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Avecilla, C. Platas‐Iglesias, Raquel Rodríguez-Cortiñas, Geo, roy Guillemot, J. Bünzli, C. Brondino, C. Geraldes, A. D. Blas, T. Rodríguez-Blas
The Schiff base axial macrobicyclic ligand L1 forms 4f–4f and 4f–3d cryptates with formula [Gd2(L1 − 3H)(NO3)2](NO3)·1.5H2O (1), [Tb2(L1 − 3H)(NO3)2](NO3)·3EtOH·H2O (2), [GdCu(L1 − 3H)(NO3)](NO3)·H2O (3), [LuCu(L1 − 3H)(NO3)](NO3)·H2O (4) and [GdZn(L1 − 3H)(NO3)](NO3)·H2O (5). The macrobicyclic receptor L1 is an azacryptand N[(CH2)2NCH–R–CHN–(CH2)2]3N (R =1,3-(2-OH-5-Me–C6H2)). The crystal structures of the five compounds have been determined by X-ray crystallography. The ligand is helically wrapped around the two metal ions, leading to pseudo-C3 symmetries around the metals. In the solid state, the conformation of the cation in 1 and 2 is Λ(δδλ)5(δδλ)5 or its enantiomeric form Δ(λλδ)5(λλδ)5, while in 3, 4 and 5 it can be described as Λ(δδλ)5(δ′δ′δ′)5 (or Δ(λλδ)5(λ′λ′λ′)5). In 1, only one enantiomer is found in the crystal lattice, whereas in the other four compounds, both enantiomers are co-crystallised. The magnetic behaviour of the homodinuclear (Gd, Gd) and the heterodinuclear (Gd, Cu) cryptates points to a significant magnetic interaction between the two metal ions. This magnetic interaction is antiferromagnetic in the case of the Gd–Gd cryptate 1 (J = −0.194(6) cm−1), but ferromagnetic for the Gd–Cu one (J = 2.2(1) cm−1). The antiferromagnetic coupling observed for 1 is one of the largest ever reported. Although the ferromagnetic coupling observed for 3 is relatively weak, which is attributed to the strong bending of the bridging network, it is considerably stronger than the one reported for [GdCu(L2 − 3H)(DMF)](ClO4)2·MeCN. In spite of the similar coordination environment of the Gd(III) ion in compounds 1, 3 and 5 their EPR spectra are different, thereby confirming the magnetic interactions between the Gd(III) ion and the Cu(II) ion in 3 and the other Gd(III) ion in 1.
{"title":"Structural characterisation, EPR and magnetic properties of f–f and f–d lanthanide(III) phenolic cryptates","authors":"F. Avecilla, C. Platas‐Iglesias, Raquel Rodríguez-Cortiñas, Geo, roy Guillemot, J. Bünzli, C. Brondino, C. Geraldes, A. D. Blas, T. Rodríguez-Blas","doi":"10.1039/B206615G","DOIUrl":"https://doi.org/10.1039/B206615G","url":null,"abstract":"The Schiff base axial macrobicyclic ligand L1 forms 4f–4f and 4f–3d cryptates with formula [Gd2(L1 \u0000− 3H)(NO3)2](NO3)·1.5H2O (1), [Tb2(L1 \u0000− 3H)(NO3)2](NO3)·3EtOH·H2O (2), [GdCu(L1 \u0000− 3H)(NO3)](NO3)·H2O (3), [LuCu(L1 \u0000− 3H)(NO3)](NO3)·H2O (4) and [GdZn(L1 \u0000− 3H)(NO3)](NO3)·H2O (5). The macrobicyclic receptor L1 is an azacryptand N[(CH2)2NCH–R–CHN–(CH2)2]3N (R =1,3-(2-OH-5-Me–C6H2)). The crystal structures of the five compounds have been determined by X-ray crystallography. The ligand is helically wrapped around the two metal ions, leading to pseudo-C3 symmetries around the metals. In the solid state, the conformation of the cation in 1 and 2 is Λ(δδλ)5(δδλ)5 or its enantiomeric form Δ(λλδ)5(λλδ)5, while in 3, 4 and 5 it can be described as Λ(δδλ)5(δ′δ′δ′)5 \u0000(or Δ(λλδ)5(λ′λ′λ′)5). In 1, only one enantiomer is found in the crystal lattice, whereas in the other four compounds, both enantiomers are co-crystallised. The magnetic behaviour of the homodinuclear (Gd, Gd) and the heterodinuclear (Gd, Cu) cryptates points to a significant magnetic interaction between the two metal ions. This magnetic interaction is antiferromagnetic in the case of the Gd–Gd cryptate 1 \u0000(J \u0000= \u0000−0.194(6) cm−1), but ferromagnetic for the Gd–Cu one (J \u0000= 2.2(1) cm−1). The antiferromagnetic coupling observed for 1 is one of the largest ever reported. Although the ferromagnetic coupling observed for 3 is relatively weak, which is attributed to the strong bending of the bridging network, it is considerably stronger than the one reported for [GdCu(L2 \u0000− 3H)(DMF)](ClO4)2·MeCN. In spite of the similar coordination environment of the Gd(III) ion in compounds 1, 3 and 5 their EPR spectra are different, thereby confirming the magnetic interactions between the Gd(III) ion and the Cu(II) ion in 3 and the other Gd(III) ion in 1.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84762511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lithium, sodium and potassium anthranilates (2-aminobenzoates) have been prepared by neutralization of anthranilic acid with the corresponding alkali hydroxides in aqueous solution. Li(Anth) and Na(Anth) crystallize as hemihydrates, K(Anth) as the monohydrate. A single crystal structure determination has shown that Li(Anth)(H2O)0.5 forms a chain structure composed of unique polyhedral compartments with ten-membered ring rims sharing two opposite rectangular faces. The strings are connected via hydrogen bonds involving the amino groups which are not part of the inner coordination sphere of the penta-coordinated lithium atoms. By contrast, Na(Anth)(H2O)0.5 has a layer structure with the hexa- and hepta-coordinated sodium atoms O,N-chelated by anthranilate anions and interconnected via bridging carboxylate groups and water molecules. Hydrogen bonding contributes to the connectivity within a given sheet with its corrugated double-layer of sodium atoms, but not beyond the layers which are shielded by the arene rings. K(Anth)(H2O) also forms a sheet structure with a single corrugated layer of seven-coordinated potassium cations O,O-chelated and bridged by the anthranilate anions and by the water molecules. The amino groups have no contact with the metal centres and are involved solely in hydrogen bonding. The hydrocarbon rings extending above and below the sheets show no π���π-stacking and are not indented.
{"title":"The structural chemistry of lithium, sodium and potassium anthranilate hydrates","authors":"F. Wiesbrock, H. Schmidbaur","doi":"10.1039/B208836N","DOIUrl":"https://doi.org/10.1039/B208836N","url":null,"abstract":"Lithium, sodium and potassium anthranilates (2-aminobenzoates) have been prepared by neutralization of anthranilic acid with the corresponding alkali hydroxides in aqueous solution. Li(Anth) and Na(Anth) crystallize as hemihydrates, K(Anth) as the monohydrate. A single crystal structure determination has shown that Li(Anth)(H2O)0.5 forms a chain structure composed of unique polyhedral compartments with ten-membered ring rims sharing two opposite rectangular faces. The strings are connected via hydrogen bonds involving the amino groups which are not part of the inner coordination sphere of the penta-coordinated lithium atoms. By contrast, Na(Anth)(H2O)0.5 has a layer structure with the hexa- and hepta-coordinated sodium atoms O,N-chelated by anthranilate anions and interconnected via bridging carboxylate groups and water molecules. Hydrogen bonding contributes to the connectivity within a given sheet with its corrugated double-layer of sodium atoms, but not beyond the layers which are shielded by the arene rings. K(Anth)(H2O) also forms a sheet structure with a single corrugated layer of seven-coordinated potassium cations O,O-chelated and bridged by the anthranilate anions and by the water molecules. The amino groups have no contact with the metal centres and are involved solely in hydrogen bonding. The hydrocarbon rings extending above and below the sheets show no π���π-stacking and are not indented.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72723105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Wong, Chun-Kin Wong, Guo‐Liang Lu, K. Cheah, Jianxin Shi, Zhenyang Lin
Synthetic routes to a series of novel oligomeric and polymeric platinum(II)-containing silylacetylenes have been developed. The CuI-catalyzed reaction of trans-[Pt(PEt3)2PhCl] with the alkynylsilane Ph2Si(CCH)2, in a basic medium, afforded the mononuclear trans-[Ph(Et3P)2PtCCSiPh2CCH] (1) and the dinuclear trans-[Ph(Et3P)2PtCCSiPh2CCPt(PEt3)2Ph] (2). Complex 1 can be utilized as a key starting material for access to the triplatinum(II) system trans-[Ph(Et3P)2PtCCSiPh2CCPt(PBu3)2CCSiPh2CCPt(PEt3)2Ph] (3). Attempted oxidative coupling of 1 only led to the isolation of the triacetylenic species trans-[Ph(Et3P)2PtCCCCCCPt(PEt3)2Ph] (5), involving cleavage of Si–C(alkyne) bonds. Soluble and thermally stable platinum(II) poly-yne silane polymer trans-[–Pt(PBu3)2CCSiPh2CC–]n (4) was prepared in good yield by CuI-catalyzed polymerization of trans-[Pt(PBu3)2Cl2] and Ph2Si(CCH)2. The single-crystal X-ray structural analyses and DFT calculations were performed on 1, 2 and 5. We report the optical absorption and photoluminescence spectra of these new metal-based oligomeric and polymeric silylacetylenes and the results are compared with platinum(II) poly-ynes with purely acetylenic and (hetero)aromatic conjugated units.
{"title":"Synthesis, structures and optical spectroscopy of photoluminescent platinum-linked poly(silylacetylenes)","authors":"W. Wong, Chun-Kin Wong, Guo‐Liang Lu, K. Cheah, Jianxin Shi, Zhenyang Lin","doi":"10.1039/B207575J","DOIUrl":"https://doi.org/10.1039/B207575J","url":null,"abstract":"Synthetic routes to a series of novel oligomeric and polymeric platinum(II)-containing silylacetylenes have been developed. The CuI-catalyzed reaction of trans-[Pt(PEt3)2PhCl] with the alkynylsilane Ph2Si(CCH)2, in a basic medium, afforded the mononuclear trans-[Ph(Et3P)2PtCCSiPh2CCH] \u0000(1) and the dinuclear trans-[Ph(Et3P)2PtCCSiPh2CCPt(PEt3)2Ph] \u0000(2). Complex 1 can be utilized as a key starting material for access to the triplatinum(II) system trans-[Ph(Et3P)2PtCCSiPh2CCPt(PBu3)2CCSiPh2CCPt(PEt3)2Ph] \u0000(3). Attempted oxidative coupling of 1 only led to the isolation of the triacetylenic species trans-[Ph(Et3P)2PtCCCCCCPt(PEt3)2Ph] \u0000(5), involving cleavage of Si–C(alkyne) bonds. Soluble and thermally stable platinum(II) poly-yne silane polymer trans-[–Pt(PBu3)2CCSiPh2CC–]n \u0000(4) was prepared in good yield by CuI-catalyzed polymerization of trans-[Pt(PBu3)2Cl2] and Ph2Si(CCH)2. The single-crystal X-ray structural analyses and DFT calculations were performed on 1, 2 and 5. We report the optical absorption and photoluminescence spectra of these new metal-based oligomeric and polymeric silylacetylenes and the results are compared with platinum(II) poly-ynes with purely acetylenic and (hetero)aromatic conjugated units.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89488190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Benjamin D. Ward, Stuart R. Dubberley, aline maisse-françois, L. Gade, P. Mountford
Reactions of the lithiated diamido-pyridine and -amine ligands Li2N2TMSNpy or Li2N2NC2,TMS with ScCl3 in tetrahydrofuran (THF) afforded the five-coordinate scandium chloride derivatives [Sc(N2TMSNpy)Cl(THF)] 1 and [Sc(N2NC2,TMS)Cl(THF)] 2 where N2TMSNpy = MeC(2-C5H4N)(CH2NSiMe3)2 and N2NC2,TMS = Me3SiN(CH2CH2NSiMe3)2. The corresponding reactions of ScCl3 with the dilithium salts of the amino N-methylated two-carbon analogue N2NC2,Me (N2NC2,Me = MeN(CH2CH2NSiMe3)2) or of the amino N-silylated three-carbon chain analogue N2NC3,TMS (N2NC3,TMS = Me3SiN(CH2CH2CH2NSiMe3)2) afforded no tractable products. In contrast, reaction of ScCl3with the homologous N-methylated three-carbon chain species Li2N2NC3,Me (N2NC3,Me = MeN(CH2CH2CH2NSiMe3)2) cleanly gave the THF-free dinuclear, chloride-bridged compound [Sc2(N2NC3,Me)2(μ-Cl)2] 3. The compounds 1–3 have been crystallographically characterised. Organometallic analogues of 1 and 2 have been prepared by protonolysis reactions of H2N2R′Npy (N2R′Npy = MeC(2-C5H4N)(CH2NR′)2 where R′ = SiMe3, Tol (4-C6H4Me) or Mes (2,4,6-C6H2Me3)) and H2N2NC2,R′ (R′ = Me or SiMe3) with [ScR3(THF)2] (R = CH2SiMe3 or Ph) in benzene which gave the five-coordinate alkyl or phenyl compounds [Sc(N2R′Npy)R(THF)] (R = CH2SiMe3, R′ = SiMe3 4, Tol 5 or Mes 6; R = Ph, R′ = SiMe3 7) and [Sc(N2NC2,R′)(CH2SiMe3)(THF)] (R′ = Me 8 or SiMe3 9). The compound 4 can also be prepared by the reaction of 1 with LiCH2SiMe3. Reaction of [Sc(CH2SiMe3)3(THF)2] with H2N2NC3,Me afforded no tractable product, and with H2N2NC3,TMS in deuterobenzene the labile compound [Sc(N2NC3,TMS)(CH2SiMe3)(THF)] 10 was observed by 1H NMR spectroscopy but could not be isolated. On one occasion the THF-free dimeric alkyl species [Sc2(N2TolNpy)2(CH2SiMe3)2] 11 was obtained. This compound possesses one bridging and one terminal amido nitrogen per N2TolNpy ligand. The X-ray crystal structures of 6 and 11 have been determined. The monomeric compounds 1, 2 and 6 all have trigonal bipyramidal Sc centres in the solid state; the neutral donors take up the axial sites, and the amido nitrogens and either Cl or CH2SiMe3 occupy the equatorial ones.
{"title":"Scandium chloride, alkyl and phenyl complexes of diamido-donor ligands","authors":"Benjamin D. Ward, Stuart R. Dubberley, aline maisse-françois, L. Gade, P. Mountford","doi":"10.1039/B209382K","DOIUrl":"https://doi.org/10.1039/B209382K","url":null,"abstract":"Reactions of the lithiated diamido-pyridine and -amine ligands Li2N2TMSNpy or Li2N2NC2,TMS with ScCl3 in tetrahydrofuran (THF) afforded the five-coordinate scandium chloride derivatives [Sc(N2TMSNpy)Cl(THF)] 1 and [Sc(N2NC2,TMS)Cl(THF)] 2 where N2TMSNpy = MeC(2-C5H4N)(CH2NSiMe3)2 and N2NC2,TMS = Me3SiN(CH2CH2NSiMe3)2. The corresponding reactions of ScCl3 with the dilithium salts of the amino N-methylated two-carbon analogue N2NC2,Me (N2NC2,Me = MeN(CH2CH2NSiMe3)2) or of the amino N-silylated three-carbon chain analogue N2NC3,TMS (N2NC3,TMS = Me3SiN(CH2CH2CH2NSiMe3)2) afforded no tractable products. In contrast, reaction of ScCl3with the homologous N-methylated three-carbon chain species Li2N2NC3,Me (N2NC3,Me = MeN(CH2CH2CH2NSiMe3)2) cleanly gave the THF-free dinuclear, chloride-bridged compound [Sc2(N2NC3,Me)2(μ-Cl)2] 3. The compounds 1–3 have been crystallographically characterised. Organometallic analogues of 1 and 2 have been prepared by protonolysis reactions of H2N2R′Npy (N2R′Npy = MeC(2-C5H4N)(CH2NR′)2 where R′ = SiMe3, Tol (4-C6H4Me) or Mes (2,4,6-C6H2Me3)) and H2N2NC2,R′ (R′ = Me or SiMe3) with [ScR3(THF)2] (R = CH2SiMe3 or Ph) in benzene which gave the five-coordinate alkyl or phenyl compounds [Sc(N2R′Npy)R(THF)] (R = CH2SiMe3, R′ = SiMe3 4, Tol 5 or Mes 6; R = Ph, R′ = SiMe3 7) and [Sc(N2NC2,R′)(CH2SiMe3)(THF)] (R′ = Me 8 or SiMe3 9). The compound 4 can also be prepared by the reaction of 1 with LiCH2SiMe3. Reaction of [Sc(CH2SiMe3)3(THF)2] with H2N2NC3,Me afforded no tractable product, and with H2N2NC3,TMS in deuterobenzene the labile compound [Sc(N2NC3,TMS)(CH2SiMe3)(THF)] 10 was observed by 1H NMR spectroscopy but could not be isolated. On one occasion the THF-free dimeric alkyl species [Sc2(N2TolNpy)2(CH2SiMe3)2] 11 was obtained. This compound possesses one bridging and one terminal amido nitrogen per N2TolNpy ligand. The X-ray crystal structures of 6 and 11 have been determined. The monomeric compounds 1, 2 and 6 all have trigonal bipyramidal Sc centres in the solid state; the neutral donors take up the axial sites, and the amido nitrogens and either Cl or CH2SiMe3 occupy the equatorial ones.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87184749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Sachdev, C. Wagner, Cordula Preis, V. Huch, M. Veith
The syntheses and crystal structures of three new furfurylamides are described, tetrameric lithium furfurylamide (1), dimeric magnesium furfurylamide (2), and dimeric dimethylaluminiumfurfurylamide (3). The compounds were characterized by 1H-, 13C-, 29Si- and 7Li- NMR spectroscopy and by X-ray crystallography.
{"title":"Coordination chemistry of furfurylsilylamides","authors":"H. Sachdev, C. Wagner, Cordula Preis, V. Huch, M. Veith","doi":"10.1039/B205350K","DOIUrl":"https://doi.org/10.1039/B205350K","url":null,"abstract":"The syntheses and crystal structures of three new furfurylamides are described, tetrameric lithium furfurylamide (1), dimeric magnesium furfurylamide (2), and dimeric dimethylaluminiumfurfurylamide (3). The compounds were characterized by 1H-, 13C-, 29Si- and 7Li- NMR spectroscopy and by X-ray crystallography.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75436725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Two new coordination polymers were synthesized under ambient conditions in water by combining a cobalt(II) or copper(II) metal salt with 1,2,4,5-benzenetetracarboxylate (BTEC) and N-methylimidazole (Meim), forming Co2(BTEC)(Meim)4(H2O)4·H2O (1) and Cu2(BTEC)(Meim)4 (2). Compounds 1 and 2 were characterized by X-ray crystallography, powder X-ray diffraction, TGA, FT-IR and elemental analysis. The crystal structures and 2D polymeric structures of compounds 1 and 2 are reported. Coordination polymer 1 crystallizes in the monoclinic space group C2/c. Coordination polymer 2 crystallizes in the triclinic space group P. Both 1 and 2 are made up of infinite sheets of BTEC ligands and metal ions. The sheets in 1 are puckered, giving an offset zigzag sheet topology, while the sheets in 2 are flat. Significant π–π stacking between Meim rings on adjacent sheets contributes to inter-sheet interactions in both 1 and 2. While hydrogen bonding does not play a role in 2, significant hydrogen bonding between sheets in 1 also stabilizes inter-sheet interactions.
{"title":"Copper(II) and cobalt(II) coordination polymers with bridging 1,2,4,5-benzenetetracarboxylate and N-methylimidazole: coordination number-determined sheet topology","authors":"Deping Cheng, M. Khan, R. Houser","doi":"10.1039/B207559H","DOIUrl":"https://doi.org/10.1039/B207559H","url":null,"abstract":"Two new coordination polymers were synthesized under ambient conditions in water by combining a cobalt(II) or copper(II) metal salt with 1,2,4,5-benzenetetracarboxylate (BTEC) and N-methylimidazole (Meim), forming Co2(BTEC)(Meim)4(H2O)4·H2O (1) and Cu2(BTEC)(Meim)4 \u0000(2). Compounds 1 and 2 were characterized by X-ray crystallography, powder X-ray diffraction, TGA, FT-IR and elemental analysis. The crystal structures and 2D polymeric structures of compounds 1 and 2 are reported. Coordination polymer 1 crystallizes in the monoclinic space group C2/c. Coordination polymer 2 crystallizes in the triclinic space group P. Both 1 and 2 are made up of infinite sheets of BTEC ligands and metal ions. The sheets in 1 are puckered, giving an offset zigzag sheet topology, while the sheets in 2 are flat. Significant π–π stacking between Meim rings on adjacent sheets contributes to inter-sheet interactions in both 1 and 2. While hydrogen bonding does not play a role in 2, significant hydrogen bonding between sheets in 1 also stabilizes inter-sheet interactions.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74001868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Synthetic routes to zinc complexes supported by sterically demanding bis(phosphinimino)methyl ligands are reported. Two aryl-substituted ligand precursors have been utilised, [CH2(Ph2PNC6H2Me3-2,4,6)2], 1, and [CH2(Ph2PNPh)(Ph2PNC6H2Me3-2,4,6)], 2. The second of these is the first example of an asymmetric bis(phosphinimino)methane. These ligands are converted to three-coordinate RZnX complexes (R = 1; X = Me, N(SiMe3)2; R = 2; X = Me) with either C2 or Cs symmetry in solution by reaction with either ZnMe2 or Zn[N(SiMe3)2]2 in toluene. All three derivatives have been shown to exist as three-coordinate monomers in the solid state by X-ray diffraction analysis. Protonolysis of these compounds with the bulky phenol 2,4-tBu2C6H3OH or triphenylmethanol resulted in the isolation of a series of three-coordinate aryloxy or alkoxyzinc derivatives. In contrast, reaction with less sterically demanding alcohols resulted in protonation of the bis(phosphinimino)methyl ligand. A similar result was obtained from reaction of RZnMe (R = 1) and triphenylsilanol and the product is the first example of a bis(triorganosiloxy)zinc compound to be structurally characterised. All the compounds have been examined for activity in ring opening polymerisation catalysis of rac-lactide. The aryloxy and triphenylmethoxy derivatives are active catalysts; however, no evidence of true ‘living’ behaviour or stereocontrol of diastereomer insertion has been observed.
{"title":"Synthesis of C2 and Cs symmetric zinc complexes supported by bis(phosphinimino)methyl ligands and their use in ring opening polymerisation catalysis","authors":"M. Hill, P. Hitchcock","doi":"10.1039/B207358G","DOIUrl":"https://doi.org/10.1039/B207358G","url":null,"abstract":"Synthetic routes to zinc complexes supported by sterically demanding bis(phosphinimino)methyl ligands are reported. Two aryl-substituted ligand precursors have been utilised, [CH2(Ph2PNC6H2Me3-2,4,6)2], 1, and [CH2(Ph2PNPh)(Ph2PNC6H2Me3-2,4,6)], 2. The second of these is the first example of an asymmetric bis(phosphinimino)methane. These ligands are converted to three-coordinate RZnX complexes (R = 1; X = Me, N(SiMe3)2; R = 2; X = Me) with either C2 or Cs symmetry in solution by reaction with either ZnMe2 or Zn[N(SiMe3)2]2 in toluene. All three derivatives have been shown to exist as three-coordinate monomers in the solid state by X-ray diffraction analysis. Protonolysis of these compounds with the bulky phenol 2,4-tBu2C6H3OH or triphenylmethanol resulted in the isolation of a series of three-coordinate aryloxy or alkoxyzinc derivatives. In contrast, reaction with less sterically demanding alcohols resulted in protonation of the bis(phosphinimino)methyl ligand. A similar result was obtained from reaction of RZnMe (R = 1) and triphenylsilanol and the product is the first example of a bis(triorganosiloxy)zinc compound to be structurally characterised. All the compounds have been examined for activity in ring opening polymerisation catalysis of rac-lactide. The aryloxy and triphenylmethoxy derivatives are active catalysts; however, no evidence of true ‘living’ behaviour or stereocontrol of diastereomer insertion has been observed.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88537145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Susana Alves, A. Paulo, J. Correia, A. Domingos, I. Santos
The coordination capabilities of the pyrazolyl containing ligands pz*(CH2)2NH(CH2)2pz*, pz*(CH2)2NH(CH2)2NH2, pz*(CH2)2S(CH2)2pz* and pz*(CH2)2S(CH2)2NH2 (pz* = 3,5-Me2pz) towards the synthon (NEt4)2[ReBr3(CO)3] (1) were studied. Depending on the reaction conditions, neutral or cationic Re(I) tricarbonyl complexes have been isolated: [ReBr(CO)3(κ2-pz*(CH2)2NH(CH2)2pz*)] (2), [ReBr(CO)3(κ2-pz*(CH2)2S(CH2)2pz*)] (3) [Re(CO)3(κ3-pz*(CH2)2NH(CH2)2pz*)]Br (4), [Re(CO)3(κ2-pz*(CH2)2S(CH2)2pz*)MeOH]Br (5), [Re(CO)3(κ3-pz*(CH2)2NH(CH2)2NH2)]Br (6) and [Re(CO)3(κ3-pz*(CH2)2S(CH2)2NH2)]Br (7). Complexes 2–7 have been characterized by the normal techniques, including X-ray crystallographic analysis in the case of 3, 4, 6 and 7. In these complexes the Re atom adopts a distorted octahedral coordination, being one of the triangular faces defined by the three carbonyl groups and the other three remaining coordination positions by the bidentate and the bromide ligands (3), or by the tridentate and neutral pyrazolyl containing ligands (4, 6, 7). Complexes 2–4, 6 and 7 are static in solution and the 1H NMR data indicate clearly a κ2-coordination mode of the ligand in 2 and 3 and a κ3-coordination in 4, 6 and 7, which agrees with the coordination mode found in the solid state. Compound 5 displays a fluxional behaviour in solution as shown by variable temperature 1H NMR studies. No X-ray data exists for this complex but the pattern obtained for the NMR spectrum at 215 K indicates a κ2-coordination mode for the pyrazolyl containing ligand.
{"title":"Coordination capabilities of pyrazolyl containing ligands towards the fac-[Re(CO)3]+ moiety","authors":"Susana Alves, A. Paulo, J. Correia, A. Domingos, I. Santos","doi":"10.1039/B207164A","DOIUrl":"https://doi.org/10.1039/B207164A","url":null,"abstract":"The coordination capabilities of the pyrazolyl containing ligands pz*(CH2)2NH(CH2)2pz*, pz*(CH2)2NH(CH2)2NH2, pz*(CH2)2S(CH2)2pz* and pz*(CH2)2S(CH2)2NH2 \u0000(pz* \u0000= 3,5-Me2pz) towards the synthon (NEt4)2[ReBr3(CO)3] \u0000(1) were studied. Depending on the reaction conditions, neutral or cationic Re(I) tricarbonyl complexes have been isolated: [ReBr(CO)3(κ2-pz*(CH2)2NH(CH2)2pz*)] \u0000(2), [ReBr(CO)3(κ2-pz*(CH2)2S(CH2)2pz*)] \u0000(3) \u0000[Re(CO)3(κ3-pz*(CH2)2NH(CH2)2pz*)]Br (4), [Re(CO)3(κ2-pz*(CH2)2S(CH2)2pz*)MeOH]Br (5), [Re(CO)3(κ3-pz*(CH2)2NH(CH2)2NH2)]Br (6) and [Re(CO)3(κ3-pz*(CH2)2S(CH2)2NH2)]Br (7). Complexes 2–7 have been characterized by the normal techniques, including X-ray crystallographic analysis in the case of 3, 4, 6 and 7. In these complexes the Re atom adopts a distorted octahedral coordination, being one of the triangular faces defined by the three carbonyl groups and the other three remaining coordination positions by the bidentate and the bromide ligands (3), or by the tridentate and neutral pyrazolyl containing ligands (4, 6, 7). Complexes 2–4, 6 and 7 are static in solution and the 1H NMR data indicate clearly a κ2-coordination mode of the ligand in 2 and 3 and a κ3-coordination in 4, 6 and 7, which agrees with the coordination mode found in the solid state. Compound 5 displays a fluxional behaviour in solution as shown by variable temperature 1H NMR studies. No X-ray data exists for this complex but the pattern obtained for the NMR spectrum at 215 K indicates a κ2-coordination mode for the pyrazolyl containing ligand.","PeriodicalId":17317,"journal":{"name":"Journal of The Chemical Society-dalton Transactions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76952781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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