The structures of alkali metal complexes of silyl-substituted ansa-tris(allyl) ligands [RSi(C 3 H... more The structures of alkali metal complexes of silyl-substituted ansa-tris(allyl) ligands [RSi(C 3 H 3 SiMe 3 ) 3 ] 3-(R = Me, L 1 ; or Ph, L 2 ) are discussed. Triple deprotonation of L 1 H 3 by nBuNa/tmeda affords [L 1 {Na(tmeda)} 3 ] (4) in which the sodium cations are complexed by η n -allyl ligands and the silyl substituents adopt [exo,exo][endo,exo] 2 stereochemistries in one crystallographically disordered form and [endo,exo] 3 in another. Triple deprotonation of L 2 H 3 with nBuLi/tmeda results in the formation of [L 2 {Li(tmeda)} 3 ] (5), the structure of which features silyl substituents with [exo,exo] 2 [endo,exo] stereochemistries. The trisodium complex [L 2 Na{Na-(tmeda)} 2 ] 2 (6) consists of a hexa(allylsodium) macrocycle that aggregates as a result of cation-π interactions between the phenyl substituents and the sodium cations. An attempt to prepare the tripotassium complex of L 1 resulted in the formation of the bimetallic potassium/lithium complex [a]
Single-molecule magnets are a type of coordination compound that can retain magnetic information ... more Single-molecule magnets are a type of coordination compound that can retain magnetic information at low temperatures. Single-molecule magnets based on lanthanides have accounted for many important advances, including systems with very large energy barriers to reversal of the magnetization, and a di-terbium complex that displays magnetic hysteresis up to 14 K and shows strong coercivity. Ligand design is crucial for the development of new single-molecule magnets: organometallic chemistry presents possibilities for using unconventional ligands, particularly those with soft donor groups. Here we report dysprosium single-molecule magnets with neutral and anionic phosphorus donor ligands, and show that their properties change dramatically when varying the ligand from phosphine to phosphide to phosphinidene. A phosphide-ligated, trimetallic dysprosium single-molecule magnet relaxes via the second-excited Kramers' doublet, and, when doped into a diamagnetic matrix at the single-ion lev...
Dalton transactions (Cambridge, England : 2003), Jan 7, 2004
Manganocene, Cp(2)Mn, has been employed as a precursor in the synthesis of a range of Mn(II) dime... more Manganocene, Cp(2)Mn, has been employed as a precursor in the synthesis of a range of Mn(II) dimers of the type [CpMn(micro-X)](2)[X = 8-NHC(9)H(6)N (1), N(Ph)(C(5)H(4)N)(2), N(4-EtC(6)H(4))(C(5)H(4)N)(3) and C[triple bond]CPh (4)] as well as the bis-adduct [Cp(2)Mn[HN=C(NMe(2))(2)](2)](5). The solid-state structures of 1-5 are reported. Variable-temperature magnetic measurements have been used to assess the extent of Mn(micro-X)Mn communication within the dimers of 1-4 as a function of the bridging ligands (X).
The structures of alkali metal complexes of silyl-substituted ansa-tris(allyl) ligands [RSi(C 3 H... more The structures of alkali metal complexes of silyl-substituted ansa-tris(allyl) ligands [RSi(C 3 H 3 SiMe 3 ) 3 ] 3-(R = Me, L 1 ; or Ph, L 2 ) are discussed. Triple deprotonation of L 1 H 3 by nBuNa/tmeda affords [L 1 {Na(tmeda)} 3 ] (4) in which the sodium cations are complexed by η n -allyl ligands and the silyl substituents adopt [exo,exo][endo,exo] 2 stereochemistries in one crystallographically disordered form and [endo,exo] 3 in another. Triple deprotonation of L 2 H 3 with nBuLi/tmeda results in the formation of [L 2 {Li(tmeda)} 3 ] (5), the structure of which features silyl substituents with [exo,exo] 2 [endo,exo] stereochemistries. The trisodium complex [L 2 Na{Na-(tmeda)} 2 ] 2 (6) consists of a hexa(allylsodium) macrocycle that aggregates as a result of cation-π interactions between the phenyl substituents and the sodium cations. An attempt to prepare the tripotassium complex of L 1 resulted in the formation of the bimetallic potassium/lithium complex [a]
Ab initio calculations on the octahedral dysprosium aluminate complex [Dy(AlMe4)3] (1) predict we... more Ab initio calculations on the octahedral dysprosium aluminate complex [Dy(AlMe4)3] (1) predict weak SMM properties. Dynamic magnetic susceptibility measurements on 1 confirm the theoretical predictions, revealing fast relaxation of the magnetization via quantum tunnelling.
The ion-contact complexes [{(eta(5)-Cp)(2)Mn(eta(2):eta(5)-Cp)K}(3)]x0.5 THF (1x0.5 THF) and [{(e... more The ion-contact complexes [{(eta(5)-Cp)(2)Mn(eta(2):eta(5)-Cp)K}(3)]x0.5 THF (1x0.5 THF) and [{(eta(2)-Cp)(2)(eta(2);eta(5)-MeCp)MnK(thf)}]x2 THF (2x2 THF) and ion-separated complexes [Mg(thf)(6)][(eta(2)-Cp)(3)Mn](2) (3), [Mg(thf)(6)][(eta(2)-Cp)(eta(2)-MeCp)(2)Mn)](2)x0.5 THF (4x0.5 THF), [Mg(thf)(6)][(eta(2)-MeCp)(3)Mn)](2)x0.5 THF (5x0.5 THF) and [Li([12]crown-4)](5)[(eta-Cp)(3)Mn](5) (6) (Cp=C(5)H(5), CpMe=C(5)H(4)CH(3)), have been prepared and structurally characterised. The effects of varying the Cp and CpMe ligands in complexes 1-5 have been probed by variable-temperature magnetic susceptibility measurements and EPR spectroscopic studies.
The synthesis and structure of [{MgCl(thf)2}3(mu3-C3H5)2]2[Mg(C3H5)4], which contains both a cati... more The synthesis and structure of [{MgCl(thf)2}3(mu3-C3H5)2]2[Mg(C3H5)4], which contains both a cationic cluster Grignard and a tetraorganomagnesiate dianion, are reported.
Alkali metal complexes of two types of ansa-tris(allyl) ligand are reported; a monoanionic ansa-t... more Alkali metal complexes of two types of ansa-tris(allyl) ligand are reported; a monoanionic ansa-tris(allyl) ligand containing tin(II) is formally valence isoelectronic to the cyclopentadienyl ligand and a trianionic ansa-tris(allyl) ligand containing silicon(IV) is formally valence isoelectronic to an ansa-metallocene ligand; the potential wider use of these tripodal ligands in coordination chemistry is discussed.
Hexagonal [(eta 2-Cp)3MnK.1.5thf] 1 and ion-separated [(eta 2-Cp)3Mn]2[Mg(thf)6].2thf 2 are obtai... more Hexagonal [(eta 2-Cp)3MnK.1.5thf] 1 and ion-separated [(eta 2-Cp)3Mn]2[Mg(thf)6].2thf 2 are obtained from reactions of CpK and Cp2Mg, respectively, with manganocene, Cp2Mn; they are the first complexes to be structurally characterised containing the [Cp3Mn]- anion.
The reactions of manganocene, Cp2Mn, with 2-aminopyridine (L1H) or 2-amino-3-bromo-5-methylpyridi... more The reactions of manganocene, Cp2Mn, with 2-aminopyridine (L1H) or 2-amino-3-bromo-5-methylpyridine (L2H) give the novel hexanuclear and octanuclear Mn(II) amido cage compounds [Cp2Mn3(L1)4]2 (1) and [Mn8(L2)12(mu 4-O)2] (2); magnetic measurements on which provide a rare insight into the magnetic properties of amido-bridged metal clusters.
The structures of alkali metal complexes of silyl-substituted ansa-tris(allyl) ligands [RSi(C 3 H... more The structures of alkali metal complexes of silyl-substituted ansa-tris(allyl) ligands [RSi(C 3 H 3 SiMe 3 ) 3 ] 3-(R = Me, L 1 ; or Ph, L 2 ) are discussed. Triple deprotonation of L 1 H 3 by nBuNa/tmeda affords [L 1 {Na(tmeda)} 3 ] (4) in which the sodium cations are complexed by η n -allyl ligands and the silyl substituents adopt [exo,exo][endo,exo] 2 stereochemistries in one crystallographically disordered form and [endo,exo] 3 in another. Triple deprotonation of L 2 H 3 with nBuLi/tmeda results in the formation of [L 2 {Li(tmeda)} 3 ] (5), the structure of which features silyl substituents with [exo,exo] 2 [endo,exo] stereochemistries. The trisodium complex [L 2 Na{Na-(tmeda)} 2 ] 2 (6) consists of a hexa(allylsodium) macrocycle that aggregates as a result of cation-π interactions between the phenyl substituents and the sodium cations. An attempt to prepare the tripotassium complex of L 1 resulted in the formation of the bimetallic potassium/lithium complex [a]
Single-molecule magnets are a type of coordination compound that can retain magnetic information ... more Single-molecule magnets are a type of coordination compound that can retain magnetic information at low temperatures. Single-molecule magnets based on lanthanides have accounted for many important advances, including systems with very large energy barriers to reversal of the magnetization, and a di-terbium complex that displays magnetic hysteresis up to 14 K and shows strong coercivity. Ligand design is crucial for the development of new single-molecule magnets: organometallic chemistry presents possibilities for using unconventional ligands, particularly those with soft donor groups. Here we report dysprosium single-molecule magnets with neutral and anionic phosphorus donor ligands, and show that their properties change dramatically when varying the ligand from phosphine to phosphide to phosphinidene. A phosphide-ligated, trimetallic dysprosium single-molecule magnet relaxes via the second-excited Kramers' doublet, and, when doped into a diamagnetic matrix at the single-ion lev...
Dalton transactions (Cambridge, England : 2003), Jan 7, 2004
Manganocene, Cp(2)Mn, has been employed as a precursor in the synthesis of a range of Mn(II) dime... more Manganocene, Cp(2)Mn, has been employed as a precursor in the synthesis of a range of Mn(II) dimers of the type [CpMn(micro-X)](2)[X = 8-NHC(9)H(6)N (1), N(Ph)(C(5)H(4)N)(2), N(4-EtC(6)H(4))(C(5)H(4)N)(3) and C[triple bond]CPh (4)] as well as the bis-adduct [Cp(2)Mn[HN=C(NMe(2))(2)](2)](5). The solid-state structures of 1-5 are reported. Variable-temperature magnetic measurements have been used to assess the extent of Mn(micro-X)Mn communication within the dimers of 1-4 as a function of the bridging ligands (X).
The structures of alkali metal complexes of silyl-substituted ansa-tris(allyl) ligands [RSi(C 3 H... more The structures of alkali metal complexes of silyl-substituted ansa-tris(allyl) ligands [RSi(C 3 H 3 SiMe 3 ) 3 ] 3-(R = Me, L 1 ; or Ph, L 2 ) are discussed. Triple deprotonation of L 1 H 3 by nBuNa/tmeda affords [L 1 {Na(tmeda)} 3 ] (4) in which the sodium cations are complexed by η n -allyl ligands and the silyl substituents adopt [exo,exo][endo,exo] 2 stereochemistries in one crystallographically disordered form and [endo,exo] 3 in another. Triple deprotonation of L 2 H 3 with nBuLi/tmeda results in the formation of [L 2 {Li(tmeda)} 3 ] (5), the structure of which features silyl substituents with [exo,exo] 2 [endo,exo] stereochemistries. The trisodium complex [L 2 Na{Na-(tmeda)} 2 ] 2 (6) consists of a hexa(allylsodium) macrocycle that aggregates as a result of cation-π interactions between the phenyl substituents and the sodium cations. An attempt to prepare the tripotassium complex of L 1 resulted in the formation of the bimetallic potassium/lithium complex [a]
Ab initio calculations on the octahedral dysprosium aluminate complex [Dy(AlMe4)3] (1) predict we... more Ab initio calculations on the octahedral dysprosium aluminate complex [Dy(AlMe4)3] (1) predict weak SMM properties. Dynamic magnetic susceptibility measurements on 1 confirm the theoretical predictions, revealing fast relaxation of the magnetization via quantum tunnelling.
The ion-contact complexes [{(eta(5)-Cp)(2)Mn(eta(2):eta(5)-Cp)K}(3)]x0.5 THF (1x0.5 THF) and [{(e... more The ion-contact complexes [{(eta(5)-Cp)(2)Mn(eta(2):eta(5)-Cp)K}(3)]x0.5 THF (1x0.5 THF) and [{(eta(2)-Cp)(2)(eta(2);eta(5)-MeCp)MnK(thf)}]x2 THF (2x2 THF) and ion-separated complexes [Mg(thf)(6)][(eta(2)-Cp)(3)Mn](2) (3), [Mg(thf)(6)][(eta(2)-Cp)(eta(2)-MeCp)(2)Mn)](2)x0.5 THF (4x0.5 THF), [Mg(thf)(6)][(eta(2)-MeCp)(3)Mn)](2)x0.5 THF (5x0.5 THF) and [Li([12]crown-4)](5)[(eta-Cp)(3)Mn](5) (6) (Cp=C(5)H(5), CpMe=C(5)H(4)CH(3)), have been prepared and structurally characterised. The effects of varying the Cp and CpMe ligands in complexes 1-5 have been probed by variable-temperature magnetic susceptibility measurements and EPR spectroscopic studies.
The synthesis and structure of [{MgCl(thf)2}3(mu3-C3H5)2]2[Mg(C3H5)4], which contains both a cati... more The synthesis and structure of [{MgCl(thf)2}3(mu3-C3H5)2]2[Mg(C3H5)4], which contains both a cationic cluster Grignard and a tetraorganomagnesiate dianion, are reported.
Alkali metal complexes of two types of ansa-tris(allyl) ligand are reported; a monoanionic ansa-t... more Alkali metal complexes of two types of ansa-tris(allyl) ligand are reported; a monoanionic ansa-tris(allyl) ligand containing tin(II) is formally valence isoelectronic to the cyclopentadienyl ligand and a trianionic ansa-tris(allyl) ligand containing silicon(IV) is formally valence isoelectronic to an ansa-metallocene ligand; the potential wider use of these tripodal ligands in coordination chemistry is discussed.
Hexagonal [(eta 2-Cp)3MnK.1.5thf] 1 and ion-separated [(eta 2-Cp)3Mn]2[Mg(thf)6].2thf 2 are obtai... more Hexagonal [(eta 2-Cp)3MnK.1.5thf] 1 and ion-separated [(eta 2-Cp)3Mn]2[Mg(thf)6].2thf 2 are obtained from reactions of CpK and Cp2Mg, respectively, with manganocene, Cp2Mn; they are the first complexes to be structurally characterised containing the [Cp3Mn]- anion.
The reactions of manganocene, Cp2Mn, with 2-aminopyridine (L1H) or 2-amino-3-bromo-5-methylpyridi... more The reactions of manganocene, Cp2Mn, with 2-aminopyridine (L1H) or 2-amino-3-bromo-5-methylpyridine (L2H) give the novel hexanuclear and octanuclear Mn(II) amido cage compounds [Cp2Mn3(L1)4]2 (1) and [Mn8(L2)12(mu 4-O)2] (2); magnetic measurements on which provide a rare insight into the magnetic properties of amido-bridged metal clusters.
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