Research Progress in Ni-Ln SMMs Single Molecule Magnets
Nickel(II) ions possess electronic configuration of 3d 8. In an octahedral field, they tend to adopt a high-spin, exhibiting paramagnetism, whereas in a square-planar field, they typically adopt a low- spin, manifesting as diamagnetism. Ni(II)can engage in ferromagnetic coupling with lanthanide ions having electronic configurations of f7-f11, such as dysprosium(III). Additionally, the second-order orbital angular momentum within Nickel(II) ions can provide substantial zero-field splitting parameters, implying the potential for significant magnetic anisotropy. Therefore, this paper reviews the typical nickel-rare earth single molecule magnets in recent years, in order to lay a certain foundation for the development of 3d-4f single molecule magnets.
Ni-Ln Single Molecule Magnets
单分子磁体(Single-Molecule Magnets, SMMs)是一类有机分子纳米磁体,晶格中分子间距远,分子间相互作用很弱,晶体的整体性质可以看做全同分子性质的叠加。它的出现使得以纳米尺度磁性配合物作为基本单元研制存储器件成为可能。SMMs在二十年来的广泛关注,主要是因为其在分子水平或纳米尺度的高密度信息存储方面的潜在应用
1993年,Sessoli R.首次报道了由12个Mn离子[Mn12O12(OCMe)16(H2O)4] (Mn12-ac)组成的金属团簇在低温下具有类似于磁畴的单分子超顺磁性
近年来,具有独特电子结构的镧系离子因其无与伦比的单离子各向异性而引起了人们的广泛关注。最显著的重镧系离子,如DyIII、TbIII、HoIII和ErIII,已被广泛用作构建SMMs的磁性中心。自第一个铁磁CuII-GdIII化合物被报道后
然而,实现基于SMM的存储技术还存在两个主要问题,一个是SMMs的缓慢磁弛豫的温度,另一个是由于SMMs的单个分子,难以沉积和处理在表面
目前,已报道的镍–稀土单分子磁体如
Complexes | Hdc/kOe | Ueff/K | τ0/s | v/mT/s | TB/K | Ref. |
[Dy2Ni2L1(bipy)2] (1) | 0 | 105(1) | 1.85 × 10−11 |
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[Dy2Ni(C7H5O2)8]∙(C7H6O2)2(2) | 1.5 | 55.19 | 5.21 × 10−8 |
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[Dy2Ni2(bipy)2(HC6H5COO)10] (3) | 0 | 57.06 | 1.80 × 10−8 |
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[Dy2Ni2(bipy)2(CH3C6H4COO)10] (4) | 0 | 37.04 | 1.16 × 10−6 |
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[Dy2Ni2(bipy)2(NO3C6H4COO)10] (5) | 0 | 4.0 | 5.47 × 10−6 |
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[Ni2Dy2(L2)4(NO3)2(DMF)2] (6) | 0 | 18.5 | 5.4 × 10−7 | 140 | 1.1 |
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[Ni2Dy2(L2)4(NO3)2(MeOH)2]∙3MeOH (8) | 0 | 21.3 | 1.5 × 10−6 |
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[Tb2Ni4(L3)2Cl2(OH)2(CH3O)2(CH3OH)6] (11) | 0 | 30 | 2.09 × 10−9 |
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[Dy2Ni4(L3)2Cl2(OH)2(CH3O)2(CH3OH)6] (12) | 0 | 32 | 1.41 × 10−8 |
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[Dy2Ni2(H2L5)2(μ3-OMe)2(CH3CN)2(NO3)4]∙4H2O (15) | 0 | 48.2 | 3.6 × 10−8 |
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[Tb2Ni2(HL4)2(μ3-OMe)2(CH3CN)2(NO3)4]∙4H2O (16) | 0 | 86.2 | 2.3 × 10−7 |
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[Dy2Ni2(HL4)2(μ3-OMe)2(CH3CN)2(NO3)4]∙4H2O (17) | 0 | 56.6 | 3.3 × 10−8 |
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[Ni2Dy3(HL6)4]Cl (18) | 0 | U1= 53.5 | τ1= 2.3 × 10−8 | 50 | 3 |
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U2= 85 | τ2= 5.9 × 10−7 | |||||
[Ni6Dy3(OH)6(HL7)6(NO3)3]∙2MeCN∙2.7Et2O∙2.4H2O (23) | 0 | 23.84 | 3.63 × 10−8 |
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[HoNi5(quinha)5F2(dfpy)10] (25) | 0 | U1= 32.7 | τ1= 9.4(2) × 10−4 | 20 | 4 |
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U2= 825.1 | τ2= 3.3(5) × 10−13 | |||||
[Ni4Dy2(CO3)2Cl2(L8)2(L9)2(CH3CN)2]∙4CH3CN∙2H2O (26) | 2 | 43(7) | 3 × 10−12 |
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[{Dy(hfac)3}2{Ni(bpca)2}]∙CHCl3 | 1 | 4.9 | 1.3(0.2) × 10−6 |
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[(L10)2Ni2Dy][ClO4] | 3.5 | 10.8 | 2.3 × 10−5 |
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[{LMe2Ni(H2O)Tb(dmf)2.5(H2O)1.5}{W(CN)8}]∙H2O·0.5dmf | 0 | 15.3 | 4.5 × 10−7 |
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[Ni(μ-L11)(μ-NO3)Dy(NO3)2]3∙2CH3OH | 1 | 19.1 | 7.2 × 10−7 |
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[Dy2Ni2(μ3-OH)2(OH)(OAc)4(HL12)2(MeOH)3](ClO4)·3MeOH | 1.2 | 7.6 | 7.5 × 10−6 |
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[Ni(μ-L11)(μ-OBz)Dy(NO3)2]∙CH3OH | 1 | 9.2 | 4.4 × 10−6 |
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[Ni(μ-L11)(μ-9-An)Dy(9-An)(NO3)2]∙3CH3CN | 1 | 10.1 | 3.4 × 10−6 |
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[Dy42Ni10(μ3-OH)68(CO3)12(CH3COO)30(H2O)70]∙(ClO4)24·80H2O | 0 | 3.43 | 1.27 × 10−6 |
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[(μ4-CO3)2{Ni(3-MeOsaltn)(MeOH)Tb(NO3)}2] | 1 | 12.2(7) | 4.6(11) × 10−7 |
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[(μ4-CO3)2{Ni(3-MeOsaltn)(MeOH)Dy(NO3)}2] | 0 | 6.6(4) | 1.6(3) × 10−6 |
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1 | 18.1(6) | 1.8(4) × 10−7 | ||||
[(μ4-CO3)2{Ni(3-MeOsaltn)(H2O)Tb(NO3)}2]∙2CH3CN·2H2O | 1 | 6.1(3) | 9.7(15) × 10−7 |
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[(μ4-CO3)2{Ni(3-MeOsaltn)(H2O)Dy(NO3)}2]∙2CH3CN∙2H2O | 1 | 14.5(4) | 4.2(8) × 10−8 |
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[Ni(3-MeOsaltn)(MeOH)x(ac)Tb(hfac)2] | 1 | 14.9(6) | 2.1(5) × 10−7 |
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[Ni2Dy2(CH3CO2)3(HL13)4(H2O)2](NO3)3 | 0 | 19 | 4.23 × 10−7 |
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[Ni3Dy3(μ3-O)(μ3-OH)3(L14)3(μ-OOCCMe3)3] | 3 | 10 | 10−6 |
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[Ni2Dy2(μ3-OH)2(O2CtBu)10[Et3NH]2] | 0 | 20 | 6.0 × 10−7 |
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[Ni2Er2(μ3-OH)2(O2CtBu)10[Et3NH]2] | 1 | 18 | 3.9 × 10−6 |
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续表
{[NH2(CH3)2]2[NiDy2(HCOO)2(abtc)2]}n | 1 | 42 | 4.7 × 10−6 |
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{[Ni(Me2valpn)]2Dy(H2O)Cr(CN)6}2∙14H2O∙2DMF | 0 | 38.9 | 4.89×10−9 |
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{[Ni(Me2valpn)]2Dy(H2O)Cr(CN)6}2∙24H2O∙2PPPO·2CH3CN | 0 | 37.2 | 6.44×10−9 |
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{[Ni(Me2valpn)]2Dy(H2O)Co(CN)6}2∙8H2O·2DMF·6CH3CN | 0 | 24.4 | 4.94×10−7 |
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{[Ni(Me2valpn)]2Tb(H2O)Cr(CN)6}2·12H2O·3DMF | 0 | 21.9 | 4.71×10−8 |
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{[Ni(Me2valpn)]2Tb(H2O)Fe(CN)6}2·13.31H2O·2DMF·2.69CH3CN | 0 | 29.6 | 4.52×10−10 |
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[Ni2Dy2(Hhms)2(CH3COO)6(CH3OH)2(H2O)2]·(NO3)2 | 0 | 16.9 | 6.5 × 10−7 |
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[Ni6Dy(L15)4(Htea)4](ClO4)2.5(NO3)0.5·5.5MeCN·H2O | 0 | 10 | 1.5 × 10−5 |
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[Dy45Ni7(OH)68(CO3)12(CH3COO)26(CH3CH2COO)6(H2O)70] | 0 | 3.42 | 9.25 × 10−7 |
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[Ni2Dy2(L16)4(NO3)2(H2O)2]·2H2O | 0 | 35.75 | 8 × 10−8 |
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[Ni4Dy2(μ3-OH)2(L17)4(OAc)8]·H2O | 0 | 11.2(2) | 8.9(6) × 10−6 |
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[Ni4Dy2(L18)2(μ-Cl)2(μ3-OH)4(H2O)6]Cl4·2H2O | 0 | 23.0 | 4.52 × 10−9 |
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[Ni4Tb2(L18)2(μ-Cl)2(μ3-OH)4(H2O)6]Cl4·2H2O | 0 | 26.3 | 1.07 × 10−9 |
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[Ni4Dy2(L18)2(μ-NCS)2(μ3-OH)4(NCS)4(H2O)2]·2MeOH·4H2O | 0 | 26.0 | 1.56 × 10−8 |
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[Ni4Tb2(L18)2(μ-NCS)2(μ3-OH)4(NCS)4(H2O)2]·14.1H2O | 0 | 30.6 | 5.03 × 10−9 |
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[NiDy(L19)(Pc)(CH3OH)]·CH3OH | 1 | 6.2 |
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[NiCe(L20)(NO3)3] | 0.5 | 8.5 | 7.7 × 10−5 |
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[NiNd(L20)(NO3)3] | 1 | 9.2 | 1.9 × 10−5 |
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[NiDy(L20)(NO3)3] | 1 | 9.3 | 2.1 × 10−5 |
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[NiEr(L20)(NO3)3] | 1 | 18.4 | 1.7 × 10−6 |
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[NiYb(L20)(NO3)3] | 1 | 18.1 | 2.1 × 10−6 |
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[Ni2Dy2(L21)2(CH3CN)3(H2O)(NO3)6]·(CH3CN)2·(H2O) | 1 | 19 | 1.6×10−8 |
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[Ni2Dy2(L22)2(CH3CN)4(NO3)6]·(CH3CN)x | 1 | 15.9 | 2.6×10−7 |
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[Dy2Ni2(3, 4-DCB)10(2, 2’-bpy)2] | 2 | 7.0 | 6.8 × 10−5 |
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[Ni(L23)Dy(H2O)4][Co(CN)6]·3H2O | 0.8 | 47.02 | 6.7×10−9 |
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[Dy2Ni4(L24)4(μ1, 3-CH3CO2)2(μ3-OH)4(MeOH)2]·4CH3OH | 0 | 13.4(5) | 3.4(2) × 10−7 | 60 | 0.7 |
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[Dy2Ni2Mn2(L24)4(μ1, 3-CH3CO2)2(μ3-OH)4(MeOH)2](NO3)2·2CH3OH | 0 | 13.0(5) | 2.8(5) × 10−7 |
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[{(NiL25)2Tb}2(μ2-Cl)2Cl2(μ3-OH)4(OH2)2]Cl2·12H2O | 0 | 13.3(5) | 3.8(8) × 10−9 |
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[{(NiL25)2Dy}2(μ2-Cl)2Cl2(μ3-OH)4(OH2)2]Cl2·16H2O | 0 | U1= 19.4(8) | τ1= 5(1) × 10−11 |
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U2= 19.8(3) | τ2= 9(1) × 10−10 | |||||
[{(NiL25)2Ho}2(μ2-Cl)2(μ3-OH)4(OH2)4]Cl4·CH3CN·1.8H2O | 0 | U1= 19.8(8) | τ1= 1.6(5) × 10−10 |
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U2= 18.5(6) | τ2= 2.4(5) × 10−9 | |||||
[Ni4Dy(L26)2(LH)2(CH3CN)3Cl]·5H2O·CH3OH | 4 | 35.9 | 4.36 × 10−9 |
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[Ni4Er(L26)2(LH)2(CH3CN)3Cl]·2H2O·2CH3OH | 4 | 31.6 | 7.94 × 10−11 |
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[Ni2Dy(EtOH)(L27)4(NO3)2Cl]·CH3CN | 3 | 9.48 | 2.25×10−6 |
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[NiDy(L28)(dca)2(NO3)]n | 1 | 26.2(5) | 2.8(4) × 10−7 |
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[Tb(hfac)3Ni(hfac)2NIT-4py(H2O)2] | 0 | 7.0 | 7.8 × 10−7 |
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[Dy2Ni4(L29)8(CH3COO)4(NO3)2] | 0 | 7.43 | 9.19 × 10−7 |
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[Dy4Ni8(μ3-OH)8(L30)8(OAc)4(H2O)4]·3.5EtOH·0.5CH3CN·5H2O | 0 | 7.66 | 1.45 × 10−6 |
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[Ni2(valpn)2Dy2(DMF)5(H2O)][Fe(1-CH3im)(CN)5]3·4DMF·12H2O | 0 | 14.8(3) | 1.4(9) × 10−6 |
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续表
[Dy2Ni2(2, 3-DCB)10(2, 2’-bpy)2] | 2 | 4.4 | 3 × 10−5 |
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[Dy4Ni8(μ3-OH)8(L31)8(OAc)4(H2O)4]·3.25EtOH·4CH3CN | 1 | 81.14(3) | 6.21(2) × 10−11 | 2 |
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[Gd2Ni3(dto)6(H2O)10]·12H2O | 2.5 | 22.7 | 1.54(5) × 10−6 |
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[Gd2Ni3(dto)6(H2O)10]·2H2O | 2.5 | 18.33 | 3.25(5) × 10−6 |
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[NiEr(L32)2(NO3)3]·0.5H2O | 1 | 12.1(2) | 3.49(2) × 10−7 |
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[NiDy(H2L33)(NO3)3]·(CH3OH)2 | 0.6 | 17.01 | 4.09 × 10−8 |
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[Ni2Dy2(L34)4(Ac)2(DMF)2]·3CH3CN | 0 | 18 | 6.85 × 10−6 |
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[Ni2Dy(Hhmmp)2{(py)2CO2}(CH3COO)2]OH | 0 | 6.44 | 1.29 × 10−7 |
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[Ni2Dy(TTTTMe)2(DMF)]BPh4 | 0 | 582 | 1.4(4) ×10−11 |
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0.3 | 582 | 1.3(4) ×10−11 |
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[Dy2Ni2(2, 5-DCB)10(phen)2] | 2 | 10 | 4.0 × 10−5 |
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HL1= 3, 5-dichlorobenzoic acid; bipy = 2, 2’-bipyridine; C7H6O2= salicylic aldehyde; H2L2= (E)-2-(2-Hydroxy-3-methoxybenzylideneamino)phenol; H2L3= N1, N3-bis(3-methoxy-salicylidene)-diethylenetriamine; H3L4= 2-(2, 3-dihydroxpropyliminomethyl)-6-methoxyphenol; H4L5= 2-(((2-hydroxy-3-methoxyphenyl)methylene)amino)-2-(hydroxymethyl)-1, 3-propanedio; H4L6= (E)-2, 2’-(2-hydroxy-3-((2-hydroxyphenylimino)methyl)-5-methylbenzylazanediyl)diethanol; H3L7= 2-(β-naphthalideneamino)-2-hydroxymethyl-1-propanol; H2quinha = quinaldichydroxamic acid, dfpy = 3, 5-difluoropyridine; H2L8= N-salicylidene-N’-3-methoxysalicylidene-1, 3-propanediamine; H2L9= N, N’-bis(salicylidene)-1, 3-propanediamine; hfac-=1, 1, 1, 5, 5, 5-hexafluoroacetylacetonate; bpca-=bis(2-pyridylcarbonyl)amine anion; L10= (S)P[N(Me)N=CH-C6H3-2-O-3-OMe]3; Hdpk = di-2-pyridyl ketoxime; LMe2= 6, 6’-((1E, 1’E)-((2, 2-dimethylpropane-1, 3-diyl)bis(azaneylylidene))bis(methaneylylidene))bis(2-methoxyphenol); dmf = dimethylformamide; H2L11= N, N’, N”-trimethyl-N, N”-bis(2-hydroxy-3-methoxy-5-methylbenzyl)diethylenetriamine; H2L12= 2-(benzothiazol-2-ylhydrazonomethyl)-6-methoxyphenol; OBz = benzoate; 9-An = 9-antharecenecarboxylate; 3-MeOsaltn = N, N’-bis(3-methoxy-2-oxybenzylidene)-1, 3-propanediaminato; HL13= 2-methoxy-6-[(E)-2’-hydroxymethyl-phenyliminomethyl]-phenolate; H2L14= 6, 6’-{(2-(dimethylamino)-ethylazanediyl)bis(methylene)}bis(2-methoxy-4-methylphenol); H4abtc = 3, 3’, 5, 5’-azobenzene-tetracarboxylic acid; H2Me2valpn = N, N’-bis(3-methoxysalicylidene)-2, 2-dimethyl-1, 3-diaminopropane); H2hms = 1-(2-hydroxy-3-methoxybenzylidene)-semicarbazide; H3tea = triethanolamine; HL15= 11H-indeno[1, 2-b]quinoxalin-11-one ligand; H2L16= 3-ethoxysalicylaldehyde with 2-aminophenol; HL17= 1, 3-diamine-2-propanol; H2L18= 2-((2-(2-(2-hydroxy-3-methoxybenzylideneamino)ethylthio)ethylimino)methyl)-6-methoxyphenol); H3L19= 1, 1, 1- tris[(salicylideneamino)methyl]ethane; H2Pc = phthalocyanine; H2L20= (RR)/(SS)-1, 2-diphenyl-ethylenediamine with o-vanillin; H2L21= N, N-bis(2-hydroxy-3-methoxy-benzyliden)-1, 4- diaminobenzene; H2L22= N, N-bis(2-hydroxy-3-methoxy-benzyliden)-1, 5-diaminonaphthalene; 3, 4-HDCB = 3, 4-dichlorobenzoic acid; H2L23= N, N-ethylenebis(3-methoxysalicylaldiimine); H2L24= 2-{[(2-hydroxy-3-methoxybenzyl)imino]methyl}phenol; HL25= 2-((3-aminopropylimino)methyl)-6-methoxyphenol; H3L26= (E)-2-(hydroxymethyl)-6-(((2-hydroxyphenyl)imino)methyl)-4-methylphenol; HL27= 2-methyl-8-hydroxyquinoline; H2L28= N, N’-bis(2-hydroxy-3-methoxy-5-methylbenzyl)homopiperazine; dca = dicyanamide; hfac = hexafluoroacetylacetonate; NIT-4py = 2-(4-pyridyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide; HL29= 8- hydroxyquinoline; H2L30= 1-[[(2-hydroxyethyl)imino] methyl]-2-naphthalenol; H2valpn = N, N’-1, 3-propylenebis-3-methoxy-salicylideneamine; 2, 3-HDCB = 2, 3-dichlorobenzoic acid; H2L31= 4-bromo-2-[(2-hydroxypropylimino)methyl]phenol; dto = dithiooxalate; HL32= [2-(methylsulfanyl)phenyl]salicylaldimine; H4L33= N, N’, N”, N”’-tetra(2-hydroxy-3-methoxy-5-methylbenzyl)-1, 4, 7, 10-tetraazacyclododecane; H2L34= (E)-2-((2-hydroxy-3-methoxybenzylidene)amino)-4-methylphenol; H2hmmp = 2-[(2-hydroxyethylimino)methyl]-6-methoxyphenol; H3TTTTMe= 2, 2’, 2”-(((nitrilotris-(ethane-2, 1-diyl))tris-(azanediyl))tris(methyl-methylene))tri-phenol; 2, 5-HDCB = 2, 5dichlorobenzoic acid; phen = 1, 10-phenanthroline |
近年来,随着人们不断深入研究稀土金属配合物,镧系金属与有机配体形成的配合物引起了越来越多研究者的关注。2014年,郑智敏领导的研究小组用NiⅡ取代了配合物Dy2Co2(L1)10(bipy)2中的CoⅡ,得到了一个接近等结构的配合物,Dy2Ni2(L1)10(bipy)2(1)
2015年,唐金魁的课题组成功合成了另一种含有NiⅡ的三核3d-4f单分子磁体,标记为[DyⅢ2NiⅡ(C7H5O2)8]·(C7H6O2)2(2)
2011年,Powell研究小组
2014年,唐金魁领导的研究团队
2015年,Fu-Pei Liang等人
2013年,Vadapalli Chandrasekhar及其同事
2015年,Constantinos J. Milios和同事
2021年,童明良领导的研究小组
NiⅡ在一般配位场下具有由较大的零场分裂导致的高的磁各向异性,其分子配位结构简单,这些特点引起了人们的兴趣,并提出了进一步的综合努力应该关注的方向。通过研究总结Ni-Ln单分子磁体的最新研究进展,我们发现影响SMM性能的几个重要因素,如LnⅢ离子的各向异性、Ni与Ln间耦合相互作用力、Ni离子周围配位环境及电荷分布等等,为我们后续继续研究Ni-Ln单分子磁体提供了指导方向。
但显然,我们对单分子磁体的了解还远不够,有关Ni-Ln单分子磁体的研究报告没有非常全面,并且大部分Ni-Ln配合物在奥巴赫、拉曼、量子隧穿这些弛豫过程中的参数(Ueff、τ0、QTM)普遍是利用理性数据拟合所得,并非确切真实数据,其可靠度需要评估。由于NiⅡ离子复杂而敏感的磁结构,使其磁学性质不稳定,因此目前大部分有关Ni-Ln的研究主要集中在磁体的磁学行为及性质、合成和制备技术这些方面。虽然已取得了一些重要的进展,但仍面临着磁构关系不明朗、磁性行为理解片面、合成方法不成熟,工业化生产困难、研究方向单一等问题。这些问题有不少还处于基础研究的阶段,如果可以得到解决,相信对单分子磁体的应用会有更好的指导意义
江苏省研究生科研与实践创新计划项目(KYCX24_3546、SJCX24_1995、SJCX24_1992)资助,南通大学大型仪器开放基金资助(KFJN2471、KFJN2437),感谢南通大学分析测试中心。
*通讯作者Email: ding.xyu@ntu.edu.cn