Doubly Pyrazolate-Bridged Dinuclear Complexes of a Highly Constrained Bis-terdentate Ligand: Observation of a [High Spin-Low Spin] State for [FeII2(PMAP)2][SbF6]2·2.25(C3H8O) (PMAP = 3,5-bis{[N-(2-pyridylmethyl)amino]-methyl}-1H-pyrazolate)
摘要:
The bis-terdentate pyrazole-based ligand 3,5-bis{[N-(2-pyridylmethyl)amino]methyl}-1H-pyrazole (PMAPH) was synthesized from 3,5-(1H)-pyrazoledicarbaldehyde and 2 equiv of 2-(aminomethyl)pyridine, using sodium borohydride to reduce the imine intermediate. A family of dinuclear complexes [M-2(II/III)(PMAP)(2)](X)(2/4) was prepared by 2:2:2 reactions of MX2/PMAPH/base, where M = Zn-II and X = BF4-; M = Cu-II and X = ClO4-, BF4-, OAc-, NO3-; M = Ni-II, Fe-III and X = ClO4-, BF4-; M = Fe-II and X = SbF6-. Single crystal X-ray structure determinations on four complexes: [Fe-2(III)(PMAP)(2)](BF4)(2)center dot 2MeCN, [Ni-2(II)(PMAP)(2)](ClO4)(2)center dot 2MeCN, [Cu-2(II)(PMAP)(2)](BF4)(2)center dot 2MeCN, and [Zn-2(II)(PMAP)(2)](BF4)(2)center dot 2MeCN confirmed a dinuclear doubly pyrazolate-bridged structure for each. The two metal centers in these complexes have similar N-6 distorted octahedral coordination spheres, with all donors provided by the two deprotonated PMAP(-) ligands. Magnetic measurements reveal intra-dinuclear antiferromagnetic interactions for both the M = Cu-II and Ni-II [M-2(PMAP)(2)](BF4)(4) complexes, with J/k(B) = 252(2) K and J/k(B) = -24.7(2) K (H = -2JS(M)S(M)), respectively. Interestingly magnetic measurements show that the complex [Fe-2(II)(PMAP)(2)](SbF6)(2)center dot 2.25(C3H8O) is in a mixed high spin (HS)-low spin (LS) spin state, [HS-LS], from 300 to 1.8K, with no sign of spin crossover to a fully low spin form [LS-LS] even at 1.8 K.
Doubly Pyrazolate-Bridged Dinuclear Complexes of a Highly Constrained Bis-terdentate Ligand: Observation of a [High Spin-Low Spin] State for [FeII2(PMAP)2][SbF6]2·2.25(C3H8O) (PMAP = 3,5-bis{[N-(2-pyridylmethyl)amino]-methyl}-1H-pyrazolate)
摘要:
The bis-terdentate pyrazole-based ligand 3,5-bis{[N-(2-pyridylmethyl)amino]methyl}-1H-pyrazole (PMAPH) was synthesized from 3,5-(1H)-pyrazoledicarbaldehyde and 2 equiv of 2-(aminomethyl)pyridine, using sodium borohydride to reduce the imine intermediate. A family of dinuclear complexes [M-2(II/III)(PMAP)(2)](X)(2/4) was prepared by 2:2:2 reactions of MX2/PMAPH/base, where M = Zn-II and X = BF4-; M = Cu-II and X = ClO4-, BF4-, OAc-, NO3-; M = Ni-II, Fe-III and X = ClO4-, BF4-; M = Fe-II and X = SbF6-. Single crystal X-ray structure determinations on four complexes: [Fe-2(III)(PMAP)(2)](BF4)(2)center dot 2MeCN, [Ni-2(II)(PMAP)(2)](ClO4)(2)center dot 2MeCN, [Cu-2(II)(PMAP)(2)](BF4)(2)center dot 2MeCN, and [Zn-2(II)(PMAP)(2)](BF4)(2)center dot 2MeCN confirmed a dinuclear doubly pyrazolate-bridged structure for each. The two metal centers in these complexes have similar N-6 distorted octahedral coordination spheres, with all donors provided by the two deprotonated PMAP(-) ligands. Magnetic measurements reveal intra-dinuclear antiferromagnetic interactions for both the M = Cu-II and Ni-II [M-2(PMAP)(2)](BF4)(4) complexes, with J/k(B) = 252(2) K and J/k(B) = -24.7(2) K (H = -2JS(M)S(M)), respectively. Interestingly magnetic measurements show that the complex [Fe-2(II)(PMAP)(2)](SbF6)(2)center dot 2.25(C3H8O) is in a mixed high spin (HS)-low spin (LS) spin state, [HS-LS], from 300 to 1.8K, with no sign of spin crossover to a fully low spin form [LS-LS] even at 1.8 K.
N-di(2-pyridylmethyl)aminomethyl]pyrazole (HL1) and 3,5-bis[N,N-bis(2-diethylaminoethyl)aminomethyl]pyrazole (HL2) formed µ-pyrazolato-µ-carboxylato-dimanganese(II) complexes [Mn2L(O2CR)][BPh4]2(L = L1, R = Ph; 1; L = L2, R = Me 2) and 3,5-bis[N-(2-pyridylmethyl)aminomethyl]pyrazole (HL3) gave a di(µ-pyrazolato)-dimanganese(II) complex [Mn2L32][BPh4]23. The ditoluene adduct of 3 crystallizes in the triclinic
3,5-双[ N,N-二(2-吡啶基甲基)氨基甲基]吡唑(HL 1)和3,5-双[ N,N-双(2-二乙基氨基乙基)氨基甲基]吡唑(HL 2)形成µ-吡唑并-羧甲基二锰(II)配合物[Mn 2 L(O 2 CR)] [BPh 4 ] 2(L = L 1,R = Ph; 1 ; L = L 2,R = Me 2)和3 ,5-双[ N-(2-吡啶基甲基)氨基甲基]吡唑(HL 3)得到二(µ-吡唑并合)-二锰(II)配合物[Mn 2 L3 2 ] [BPh 4 ] 2 3。3的二甲苯加合物在三斜空间群P中结晶, a = 14.452(3), b = 15.573(5), c = 10.988(4)Å,α= 108.78(3),β= 93.31(2)和γ = 115.10(2)°。X射线衍射分析显示二(µ-吡唑并合)-二锰( II)核,Mn Mn分离度为4.181(2)Å。所有的配合物在0℃下均表现出对H
Doubly Pyrazolate-Bridged Dinuclear Complexes of a Highly Constrained Bis-terdentate Ligand: Observation of a [High Spin-Low Spin] State for [Fe<sup>II</sup><sub>2</sub>(PMAP)<sub>2</sub>][SbF<sub>6</sub>]<sub>2</sub>·2.25(C<sub>3</sub>H<sub>8</sub>O) (PMAP = 3,5-bis{[<i>N</i>-(2-pyridylmethyl)amino]-methyl}-1<i>H</i>-pyrazolate)
The bis-terdentate pyrazole-based ligand 3,5-bis[N-(2-pyridylmethyl)amino]methyl}-1H-pyrazole (PMAPH) was synthesized from 3,5-(1H)-pyrazoledicarbaldehyde and 2 equiv of 2-(aminomethyl)pyridine, using sodium borohydride to reduce the imine intermediate. A family of dinuclear complexes [M-2(II/III)(PMAP)(2)](X)(2/4) was prepared by 2:2:2 reactions of MX2/PMAPH/base, where M = Zn-II and X = BF4-; M = Cu-II and X = ClO4-, BF4-, OAc-, NO3-; M = Ni-II, Fe-III and X = ClO4-, BF4-; M = Fe-II and X = SbF6-. Single crystal X-ray structure determinations on four complexes: [Fe-2(III)(PMAP)(2)](BF4)(2)center dot 2MeCN, [Ni-2(II)(PMAP)(2)](ClO4)(2)center dot 2MeCN, [Cu-2(II)(PMAP)(2)](BF4)(2)center dot 2MeCN, and [Zn-2(II)(PMAP)(2)](BF4)(2)center dot 2MeCN confirmed a dinuclear doubly pyrazolate-bridged structure for each. The two metal centers in these complexes have similar N-6 distorted octahedral coordination spheres, with all donors provided by the two deprotonated PMAP(-) ligands. Magnetic measurements reveal intra-dinuclear antiferromagnetic interactions for both the M = Cu-II and Ni-II [M-2(PMAP)(2)](BF4)(4) complexes, with J/k(B) = 252(2) K and J/k(B) = -24.7(2) K (H = -2JS(M)S(M)), respectively. Interestingly magnetic measurements show that the complex [Fe-2(II)(PMAP)(2)](SbF6)(2)center dot 2.25(C3H8O) is in a mixed high spin (HS)-low spin (LS) spin state, [HS-LS], from 300 to 1.8K, with no sign of spin crossover to a fully low spin form [LS-LS] even at 1.8 K.