Research Progress in Co-Ln Single-Molecule Magnets
In the Co (II) ion, there are a total of 7 electrons present in the d orbitals, including 3 unpaired electrons. Due to its unquenched orbital angular momentum and relatively strong spin-orbit coupling, Co IIexhibits significant magnetic anisotropy, making it an excellent and stable spin carrier within magnetic materials. Simultaneously, Co IIreadily undergoes oxidation to Co II I, which often exhibits diamagnetic behavior in coordination environments. This property is harnessed in 3d-4f single molecule magnets (SMMs)to serve as a magnetic diluter, effectively suppressing QTM. Researchers have exploited these characteristics to synthesize numerous Co-Ln SMMs.
Co-Ln Single Molecule Magnets
单分子磁体领域的研究始于90年代初,意大利科学家Sessoli等
在过去的十几年里,关于f元素的配合物发表数量呈指数级增长,这些化合物大多都显示出磁矩的缓慢弛豫。稀土离子具有显著的单离子各向异性,大的磁矩使其成为SMMs的优良自旋载体。然而,由于4f轨道的有限径向伸展展现出了非常弱,甚至没有交换作用的现象。而其中一种提供强磁交换相互作用的方法是将3d离子引入4f系统,并且分子的大基态和磁各向异性可以通过控制磁交换相互作用力来引导。通过增加配合物中3d和4f离子之间的磁耦合,利用4f离子的单离子各向异性来增加有效能垒(Ueff)
在Co(II)离子中,d轨道上总共有7个电子,其中3个为不成对电子。与镧系金属离子相比,虽然3d过渡金属离子没有很强的自旋轨道耦合和磁矩,但是其受配体场的影响较大。通常,弱的配体场会导致电子基态和激发态之间的d轨道能量分裂能隙变小,进而使自旋轨道耦合最大化,从而增强磁各向异性
目前,已报道的钴–稀土单分子磁体如
近年来,随着人们对稀土配合物的不断研究,由镧系金属与有机配体形成的多功能配合物在许多领域表现出了其特殊的应用价值。2012年唐金魁研究组利用多齿席夫碱配体成功合成了一例线性四核配合物[Co2Dy2(L1)2(CH3COO)4(OH)2(H2O)2] (ClO4)24CH3CN (1,H2L1= N1,N3-双(3-甲氧基水杨亚胺)二乙烯三胺)
Complexes | Hdc/kOe | Ueff/K | τ0/s | v/m T/s | TB/K | Ref |
[Co2Dy2(L1)2(CH3COO)4(OH)2(H2O)2]·(ClO4)2·4CH3CN (1) | 0 | 33.8 | 3.73 × 10−6 |
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[Co2Dy(valdien)2(OCH3)2(chp)2] (2) | 2 | 71.4(4.2) | 5.6(0.3) × 10−6 |
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[Co2Tb(valdien)2(OCH3)2(chp)2] (3) | 2 | 32.3(2.6) | 2.5(1.1) × 10−10 |
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Dy2Co2(L2)10(bipy)2(4) | 0 | 118(3) | 1.85 × 10−11 |
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[DyCo(CN)6(hep)2(H2O)4] (5) | 2 | 63 | 7.1 × 10−11 |
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[Dy2CoⅡ(C7H5O2)8]·6H2O (6) | 0 | 127.27(2) | 1.69 × 10−9 |
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[Co2Dy((L3)Br)2(H2O)]NO3·3H2O (7·3H2O) | 0 | 422 | 2.4× 10−11 |
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[Co2Dy((L3)Br)2(H2O)]NO3(7) | 0 | 600 | 1.4× 10−11 |
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[Co2Dy((L3)Br)2(H2O)]NO3(7·H2O) | 0 | 522 | 1.8× 10−10 |
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[Co2Dy(TTTTCl)2(MeOH)]NO3·3MeOH (8) | 0 | 401(13) | 1.3(6) × 10−10 |
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[Co2Dy(TTTTCl)2(MeOH)] [Co(HTTTTCl)] (9) | 0 | 536(10) | 3.8(10) × 10−11 | 20 | 10 |
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(PPh4)[Dy2(bbpen)2{Co(CN)6}]·3.5MeCN (10) | 2 | 1075(22) | 4.51 × 10−13 |
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[L4CoYCoL4]NO3·CH3OH | 2 | 53 K | 7.66 × 10−7 |
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[L5CoYCoL5]NO3·CH3OH | 2 | 51.3 | 2 × 10−6 |
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[L5CoGdCoL5]NO3 | 0 | 29.4 | 1.47 × 10−7 | 2 | 1.1 |
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[L5CoGdCoL5]ClO4·2CHCl3 | 0 | 27.4 | 1.50 × 10−7 | 2 | 1.6 |
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[L5CoGdCoL5](C5HF6O2) | 0 | 29.5 | 1.3 × 10−7 | 2 | 1.6 |
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[Co2Dy2(L1)2(pdm)2(CH3COO)2(CH3OH)2] | 0 | 64.6(1) | 1.3(7) × 10−6 |
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[Dy2CoⅢ2(OMe)2(teaH)2(O2CPh)4(MeOH)4] (NO3)2·MeOH·H2O (11) | 0 | 88.8(2) | 5.64 × 10−8 |
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[Tb2CoⅢ2(OMe)2(teaH)2(O2CPh)4(MeOH)4] (NO3)2·MeOH·H2O (12) | 1 | 14.31(1) | 2.84 × 10−6 |
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[Dy2CoⅢ2(OMe)2(dea)2(O2CPh)4(MeOH)4] (13) | 0 | 102.9 | 6.05 × 10−8 |
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[Dy2CoⅢ2(OMe)2(mdea)2(O2CPh)4(NO3)2] (14) | 0 | 78.6 | 1.03 × 10−7 |
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[Dy2CoⅢ2(OMe)2(bdea)2(O2CPh)4(MeOH)4] (15) | 0 | 114.4 | 3.38 × 10−8 |
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[Dy2CoⅢ2(OMe)2(teaH)2(acac)4(NO3)2] (16) | 0 | 27 | 8.1 × 10−6 |
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[Dy2CoⅢ2(OH)2(teaH)2(acac)4(NO3)2]·4H2O (17) | 0 | 28 | 7.4 × 10−6 |
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[Dy2CoⅢ2(OMe)2(mdea)2(acac)4(NO3)2] (18) | 0 | 38 | 2.6 × 10−6 |
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[CoⅢ2Dy2(OMe)2(O2CPh-2-Cl)4(bdea)2(NO3)2] (19) | 0 | 114.9 | 1.8 × 10−8 |
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[CoⅢ2Dy2(OMe)2(O2CPh-4-tBu)4(bdea)2(NO3)(MeOH)3] (20) | 0 | 137.3 | 5.6 × 10−8 |
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[CoⅢ2CoⅡDy(OH)(O2CPh-4-OH)(bdea)3(NO3)3(MeOH)] (21) | 1.5 | 167.3 | 3.4 × 10−7 |
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[CoⅢ2Dy2(OMe)2(O2CPh-2-CF3)4(bdea)2(NO3)2] (22) | 0 | 125.8 | 1.4 × 10−8 |
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[CoⅢ2Dy2(mdea)4(hfacac)3(O2CCF3)(H2O)] (23) | 0 | 32.3 | 1.4 × 10−6 |
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[CoⅢ2Dy2(μ3-OH)2(o-tol)4(mdea)2(NO3)2] | 0 | 116.9(2) | 9.8 × 10−9 |
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[CoⅢ2Tb2(μ3-OH)2(o-tol)4(mdea)2(NO3)2] | 5 | 49.2 | 6.6 × 10−11 |
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[Co2Dy2(L6)4(NO3)2(THF)2]·4THF (24) | 0 | 117.4 | 6.2 × 10−7 | 235 | 3 |
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[Co2Dy2(L6)4(NO3)2(MeOH)2]·2CH2Cl2 | 0 | 104.8 | 9.2 × 10−7 |
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续表
[Co2Dy2(L6)4(NO3)2(DMF)2]·2C2H6CO | 0 | 94.5 | .2 × 10−6 |
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[Dy2Co2(L5)4(NO3)2(DMF)2]·2DMF | 0 | 125.1 | 2.67 × 10−6 |
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[Dy(4-MMNO)(H2O)5][Co(CN)6] (25) | 0 | 595(3) | 1.29 × 10−11 | 50 | 25 |
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[CoDy3(HBpz3)6(dto)3]·4CH3CN·2CH2Cl2(26) | 0.8 | 52 | 3.6 × 10−8 |
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[Co4Dy2(μ3-O)2(μ-N3)2(OH)2(H2O)2(HL7)4] | 0 | 73.5 | 1.86 × 10−8 |
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[L82CoII2GdⅢ][NO3] | 0 | 27.2 | 1.7 × 10−7 |
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[Co2Dy10(L9)4(OAc)16(SCN)2(MeCN)2(H2O)4(OH)2(μ3-OH)4]·2Co(SCN)4·H2O·2MeCN·2H2O | 0 | 25 | 3.14 × 10−6 |
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[CoⅢ2Dy4(OH)2(ib)8(bdea)2(NO3)4(H2O)2]·2MeCN | 0 | 26.6 | 2.26 × 10−5 |
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[CoⅢ3Dy3(µ3-OH)4(O2CtBu)6(teaH)3]·(NO3)2·H2O | 2 | 17.5 | 2.3×10−6 |
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[Dy2Co2(2, 3-DCB)10(2, 2’-bpy)2] | 2 | 2 | 7 × 10−5 |
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[Dy2Co8(μ3-OCH3)2(L10)4(HL10)2(OAc)2(NO3)2(CH3CN)2] | 0 | 14.89 | 1.68 × 10−7 |
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[Dy4Co6(L10)4(HL)2(OAc)6(OCH2CH2OH)2(HOCH2CH2OH)(H2O)] | 0 | 5.49 | 2.88 × 10−5 |
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[Dy2Co4(L11)4(NO3)2(OH)4(C2H5OH)2]·2C2H5OH | 0 | 27.50 | 3.36×10−8 |
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[CoII4Dy4(L12)4(μ1,3-Piv)4(μ1,1,3-Piv)2(η1-Piv)2(μ3-OH)4(MeOH)2] | 0 | 12.5 | 1.51×10−6 |
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[CoⅢDy(CH3CN)0.5(L13)3(NO3)3] | 3 | 2.58 | 3.11×10−5 |
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[CoⅢ2Dy4(μ3-OH)2(NO3)4(OAc)4(L32)4(DMF)2]·2C2H5OH | 0 | 27.8 | 1.94 × 10−7 |
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[DyCo(CN)6(H2L14)(H2O)(DMF)]2·5H2O | 1 | 11.17 | 1.36 × 10−6 |
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[CoⅢ2Dy3Na(CH3CH2COO)6(OH)6(NO3)4(H2O)2] | 0 | 60.3 | 9.6 × 10−8 |
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[Dy18CoIICoⅢ6(OH)14(CO3)9(CH3CH2COO)6(dea)12(H2O)30] | 0 | 3.53 | 6.03 × 10−6 |
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[Ni(L15)Dy(H2O)4][Co(CN)6]·3H2O | 0.8 | 47.02 | 6.7 × 10−9 |
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[Dy(pyzic){Dy3Co2(pyzha)6(*pyzha)(NO3)2(H2O)(MeOH)2}]2 | 0 | 1.46 | 2.4 × 10−5 |
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Dy[CoⅢ(CN)6] | 2 | 58.3(5) | 1.76(13)×10−6 |
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[(L16)4Ru2Co2](BF4)4 | 3 | 12.58 | 3.1 × 10−5 |
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[Nd(18-crown-6)(H2O)4][Co(CN)6]∙2H2O | 0.8 | 37.0 | 2.9×10−8 |
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[CoⅢ4Dy3(L17)4(μ4-O)2(μ-OMe)2(μ1,3-OAc)4(H2O)2(NO3)2]·NO3·3CH3OH·1.5H2O | 0 | 73.5 | 9.40 × 10−7 |
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[CoⅡ4Gd(OH)2(chp)4(saloh)5(H2O)(MeCN)(Solv)] | 2 | 86 | 6.95 × 10−12 |
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[CoⅡ4Dy(OH)2(chp)4(saloh)5(H2O)(MeCN)(Solv)] | 2 | 66 | 3.43× 10−7 |
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[CoⅡDy (R-HL18)(hfac)5] | 1.5 | 297.4 | 4.7 × 10−10 |
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[Co2Eu(NO3)(Piv)6(EtPy)2] | 1 | 4 | 4.7 × 10−6 |
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Co(μ-L19)(μ-CCl3COO)Y(NO3)2] | 1.2 | 8.4(6) | 3.2(4) × 10−6 |
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[Co(μ-L19)(μ-CH3COO)Y(NO3)2]·CH3CN | 1.2 | 11.0(4) | 2.5(2) × 10−6 |
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[Co(μ-L19)(μ-PhCOO)Y(NO3)2]·3CH3CN·2H2O | 1.2 | 13.7(8) | 2.6(4) × 10−6 |
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[Co(μ-L19)-(μ-tBuCOO)Y(NO3)2]·CHCl3·2H2O | 1.2 | 18.7(6) | 7.4(9) × 10−7 |
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[Co6Dy2(O)2(dhpb)6(NO3)2(DMF)2] | 0 | 11.1 | 2.8 × 10−7 |
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[Co6Ho2(O)2(dhpb)6(NO3)2(DMF)2] | 1.5 | 7.3 | 2 × 10−7 |
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[CoⅢ2Dy2(HL20)L20{(py)2CO2}{(py)2C(OCH3)O}(NO3)4CH3OH] | 0.6 | 59.4(9) | 3.1(1) × 10−8 |
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[CoⅢ{(py)2C(OH)O}2][CoⅡ2DyⅢ4DyⅢ(HL20)4(L20)4] | 0.8 | 10.9(6) | 3.5(3) × 10−8 |
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[Co2Dy2(L21)4(Ac)2(DMF)2]·3CH3CN | 0 | 15 | 2.37 × 10−5 |
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Na[CoⅢ2CoⅡCe0.65Dy0.35(H3L22)2(OAc)2(NO3)2]Cl2⋅4H2O | 1.5 | 2.13 | 1.03 × 10−4 |
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[Co2La(HL42)4(NO3)] (NO3)2 | 1.5 | 10.65 | 1.6 × 10−4 |
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[Co2Pr(HL42)4(NO3)] (NO3)2 | 2 | 15.03 | 2.63 × 10−7 |
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[Co2Gd(HL24)4(NO3)](NO3)2 | 0 | 6.69 | 3.73 × 10−8 |
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[Co2Tb(HL24)4(NO3)](NO3)2 | 0 | 1.0 | 3.15 × 10−5 |
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[Co2Dy(HL24)4(NO3)](NO3)2 | 0 | 0.58 s | 3.86 × 10−5 |
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续表
[CoⅢ2Dy4(μ3- OH)2(NO3)4(OAc)4(L25)4(DMF)2]·2C2H5OH | 0 | 31.6 | 5.66 × 10−6 |
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[Dy2Co(2, 3-pzdc)4(H2O)4]·4H2O | 2 | 5 | 10−5 |
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[L26CoⅢBr2Dy(acac)2]·CH2Cl2 | 0 | 167.66(0.03) | 8.28(5) × 10−8 | 5 | 3.5 |
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[L27CoⅢCl2Dy(acac)Cl(MeO)] | 0 | 118.72(4.27) | 4.76(2) × 10−7 | 5 | 3 |
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[L27CoⅢCl2Dy(acac)Cl(H2O)] | 0 | 75.28(13.02) | 3.47(1) × 10−6 | 5 | 3 |
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[L27CoⅢCl2Dy0.05Y0.95(acac)Cl(H2O)] | 0 | 128.27(9.61) | 4.51(1) × 10−7 | 5 | 4 |
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[CoⅡ5EuⅢ4(OMe)8(OAc)12(NO3)2(MeOH)6]·4MeOH | 2 | 16.4 |
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[CoⅡ5DyⅢ4(OH)2(OMe)6(OAc)10(NO3)4(MeOH)6]·4MeOH | 0 | 7.4 |
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[(μ3-CO3){CoⅡDyⅢL28(μ3-OH)(OH2)}3](ClO4)·3H2O | 1 | 9.2 | 1.0 × 10−7 |
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[Co(H0.5L29)Dy(DBM)2(H2O)](ClO4)0.5·3H2O | 2 | 88.9 | 1.34 × 10−10 |
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[Tb2Co2(hfac)10(NITPhPybis)2] | 0 | 7.98 | 5.4 × 10−6 |
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[Dy2Co2(hfac)10(NITPhPybis)2] | 1 | 6.03 | 5.2 × 10−5 |
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[Dy45Co7(OH)68(CO3)12(CH3COO)26(CH3CH2COO)6(H2O)70] | 0 | 4.34 | 3.25 × 10−7 |
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[CoⅢ6DyⅢ6(μ3-OH)8(nbdea)6(m-CH3C6H4COO)16]·2H2O·2CH3CN | 1 | 20.8 | 8.5 × 10−7 |
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[CoⅡ2Dy2(Hhms)2(CH3COO)6(CH3OH)2(H2O)2]·(NO3)2 | 0.8 | 13.8 | 3.2 × 10−6 |
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[CoⅢ4Dy4(μ-F)4(μ3-OH)4(o-tol)8(mdea)4]3H2O∙EtOH∙MeOH | 0 | 55.77 | 1.0 × 10−6 |
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[Co(μ-L30)(μ-NO3)Y(NO3)2] | 1 | 23.9(8) | 1.5 × 10−6 |
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[Zn0.9Co0.1(μ-L30)(μ-NO3)Y(NO3)2] | 1 | 24.8(1) | 1.4 × 10−6 |
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[Zn0.9Co0.1(μ-L30)(μ-benzoate)Y(NO3)2] | 1 | 33.2(4) | 2.5 × 10−7 |
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[Zn0.9Co0.1(μ-L30)(μ-9-anthracenecarboxylato)Y(NO3)2] | 1 | 34.6(9) | 2.3 × 10−7 |
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[CoⅢ2Yb2(OCH3)2(teaH)2(Piv)6] | 1.5 | 32.89 | 2.1 × 10−6 |
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[CoⅢ2Ho2(OCH3)2(teaH)2(Piv)6] | 3 | 42.9 | 6.2 × 10−9 |
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[CoⅢ2Dy2(OCH3)2(teaH)2(Piv)6] | 0 | 51 | 6.1 × 10−7 |
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[Dy4Co2(μ3-OH)2(NO3)4(CH3COO)4(L31)4(DMF)2] | 0 | 41.9 | 1.21×10−7 |
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[(vdpyCH2O)2Co2Dy2ac8] | 2.4 | 15.9 | 2.5 × 10−6 | 140 | 0.5 |
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[CoⅢ2Tb(L32)2(μ-O2CCH3)2(H2O)3] | 1.5 | 15.6(4) | 1 × 10−7 |
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[CoⅢ2Er(L32)2(μ-O2CCH3)2(H2O)3] | 1 | 9.9(8) | 8 × 10−7 |
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[Dy2CoⅢ2(OH)2(teaH)2(acac)6]·MeCN | 0 | 71 | 2.7 × 10−7 |
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[Dy2CoⅢ2(OH)2(bdea)2(acac)6]·2H2O | 0.5 | 38 | 2.7 × 10−7 |
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[Dy2CoⅢ2(OH)2(edea)2(acac)6]·2H2O·4MeCN | 1 | 16 | 1.3 × 10−6 |
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[CoⅢ2Dy(L33)2(μ-O2CCH3)2(H2O)3]·NO3·MeOH·4H2O | 1 | 88(8) | 1.0 × 10−8 |
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[CoⅡY(L34)(DBM)3] | 2 | 8.56 | 1.01× 10−4 |
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[Co2Dy4(μ3-OH)2(piv)4(hmmp)4(ae)2]·(NO3)2·2H2O | 0.8 | 32.4 | 4.2 × 10−7 |
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[(CoⅡ)3(CoⅢ)2Dy3(μ3-OH)5(O2CtBu)12(L35)2]·2H2O | 0 | 3.8 | 1.5 × 10−6 |
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[(CoⅢ)3Dy3(μ3-OH)4(O2CtBu)6(L35)3](NO3)2·2CH3CN·2H2O | 2 | 17.4 | 2.5 × 10−6 |
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[Co(3-MeOsaltn)(MeOH)x(ac)Tb(hfac)2] | 1 | 17.0(4) | 6.1(10) × 10−8 |
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[CoⅢ2Dy2(OH)2(bdea)2(acac)2(NO3)4] | 0 | 169 | 1.47 × 10−7 |
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[Co(μ-L36)(μ-OAc)Y(NO3)2 | 1 | 22.6 | 8.9 × 10−7 |
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[Dy42CoⅡ9CoⅢ(μ3-OH)68(CO3)12(CH3COO)30(H2O)70] | 0 | 3.67 | 9.78 × 10−7 |
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[L37CoGdCoL37]NO3 | 0 | 21.3 | 1.52 × 10−7 | 2 | 1.1 |
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[L37CoTbCoL37]NO3 | 0 | 14.5 | 3.0 × 10−6 | 140 | 1.1 |
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[{(S)P[N(Me)N=CH-C6H3-2-O-3-OMe]3}2Co2Tb] | 1.5 | 25.8 | 3.7 × 10−6 |
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[{(S)P[N(Me)N=CH-C6H3-2-O-3-OMe]3}2Co2Dy] | 0 | 14.2 | 5.1 × 10−6 |
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[{(S)P[N(Me)N=CH-C6H3-2-O-3-OMe]3}2Co2Ho] | 0 | 8 | 13 × 10−5 |
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[Dy4Co2(HL38)2(μ3-OH)2(piv)10(OH2)2] | 0 | 26.3 | 8.7 × 10−6 |
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续表
H2L1= N1, N3-bis(3-methoxysalicylidene)diethylenetriamine; H2valdien = N1, N3-bis(3-methoxysalicylidene)diethylenetriamine; Hchp = 6-chloro-2-hydroxypyridine; HL2= 3, 5-dichlorobenzoic acid; bipy = 2, 2’-bipyridine; hep = 1-(2-hydroxyethyl)-2-pyrrolidinone; C7H6O2= salicylic aldehyde; (L3)Br= 2, 2’, 2”-(((nitrilotris(ethane-2, 1-diyl))tris(azanediyl))tris(methylene))tris-(4-bromophenol); H3TTTTCl= 2, 2’, 2”-(((nitrilotris(ethane-2, 1-diyl)) tris(azanediyl)) tris(methylene))tris-(4-chlorophenol); H2bbpen = N, N’-bis(2-hydroxybenzyl)-N, N’-bis(2- picolyl)ethylene diamine; H2L4= 2-hydroxy-3-methoxybenzaldehyde with 1, 1, 1-tris(aminomethyl)ethane, Me-C(CH2NH2)3; H2L5= 2-hydroxy-3-methoxybenzaldehyde with N, N’, N”-trimethylphosphorothioic trihydrazide, P(S)[NMe-NH2]3; H2L1= N1, N3-bis(3-methoxysalicylidene)diethylenetriamine; pdmH2= 2, 6-pyridinedimethanol; teaH3= triethanolamine; H3dea = diethanolamine; H2mdea = N-methydiethanolamine; H2bdea = N-n-butyldiethanolamine; acac = acetylacetonate; hfacacH = hexafluoroacetylacetone; o-tol = o-toluate; H2L6= o-vanillin with 2-aminophenol; H2L5= (E)-2-ethoxy-6-(((2-hydroxyphenyl)imino)methyl)phenol; 4-MMNO = 4- methylmorpholine N-oxide; dto2-= dithiooxalato dianion; HBpz3-= hydrotris(pyrazolyl)borate; H3L7= 2-[Bis(pyridin-2-ylmethyl)amino]-2-(hydroxymethyl)propane-1, 3-diol; H3L8= (S)P[N(Me)NH2]3with o-vanillin; H2L9= 2-Bis(2-hydroxy-3-methoxybenzylidene) hydrazine; Hib = isobutyric acid; 2, 3-HDCB = 2, 3-dichlorobenzoic acid; H3L10= 3-amino-1,2-propanediol with 2-hydroxy-1-naphthaldehyde; H2L11= 2-(((2-hydroxy-3-methoxybenzyl) imino)methyl)-4-methoxyphenol; H2L12= 2-((2-hydroxy-3-methoxybenzylidene)amino)benzoic acid; Piv = (μ-OH2)(O2CCMe3)4(HO2CCMe3)4; HL13= 8-hydroxyquinoline; H2L32= (E)-1-(((2-(hydroxymethyl)phenyl)imino)methyl)nap- hthalen-2-ol; H2L14= 2,6-diylbis(ethan-1-yl-1-ylidene)-di(isonicotinohydrazide); H2L15= N, N-ethylenebis(3-methoxysalicylaldiimine); H2pyzha = pyrazinehydroxamic acid; Hpyzic = pyrazinic acid; HL16= bis(tridentate) pyrazolate-bridged ligand; H2L17= 3-methoxysalicyl-aldehyde with 2-amino-2-methyl-1-propanol; Hchp = deprotonated 6‐chloro‐2‐ hydroxypyridine; H2saloh = 3,5‐ditert‐butylsalicylic acid; HL18= chiral nitronyl-nitroxide ligands; H2L19= Fe[(C5H4){-C(Me)=N−N=CH-C6H3-2-OH-3- OCH3}]2; H2dhpb = 6, 6’-dihydroxyl-2, 2’-bipyridine; H3L20= 2-((2-hydroxy-benzylidene)amino)propane-1, 3-diol; (py)2C(OH)2= the gem-diol form of di-2-pyridyl ketone (dpk); (py)2C(OCH3)OH = the hemiacetal form of dpk; H2L21= (E)-2-((2-hydroxy-3-methoxybenzylidene)amino)-4-methylphenol; H6L22= bis-tris propane; H2L23= 2-methoxy-6-[(E)-2’-hydroxymethyl-phenyliminomethyl]-phenol; H2L24= 2-[(2-hydroxymethyl-phenylimino)-methyl]-6-methoxy-phenol; H2L25= (E)-4-chloro-2-(((2-(hydroxymethyl) phenyl)imino)methyl)phenol; 2, 3-H2pzdc = pyrazine-2, 3-dicarboxylic acid; H2L26= N, N’-bis(2-oxy-3-methoxybenzylidene)-1,2-phenyl-enediamine; H2L27= N, N’-bis(2-oxy-3-methoxybenzylidene)-1, 2-diaminocyclohexane); H3L28= 6, 6’, 6”-(nitrilotris(methylene))tris(2-methoxy-4-methylphenol); H4L29= 2, 2’-[1, 2-ethanediylbis[(hydroxyethylimino)methylene]]bis[6-methoxy-4-methyl-phenol]; HDBM = dibenzoylmethane; NITPhPybis = 5-(4-pyridyl)-1, 3-bis(1’-oxyl-3’-oxido-4’, 4’, 5’, 5’-tetramethyl-4, 5-hydro-1H-imidazol-2-yl)benzene; H2hms = 1-(2-hydroxy-3-methoxybenzy-lidene)-semicarbazide; H2L30= N, N’, N”-trimethyl-N, N”-bis(2-hydroxy-3-methoxy-5-methylbenzyl)diethylenetriamine; H2L31= 2-((2-(hydroxymethyl)phenylimino)methyl)-6-methoxyphenol; H3vdpyCH2OH = 1, 5-dimethyl-3-[3’- (hydroxymethyl)-2’-pyridine]-6-oxotetrazane; H3L32= 2-methoxy-6-[{2-(2-hydroxyethylamino)ethyl-imino}methyl]phenol; edeaH2= N-ethyldiethanolamine; H3L33= 2-methoxy-6-[{2-(2-hydroxyethylamino)ethylimino}methyl]phenol; H2L34= N, N’-dimethyl-N, N’-(2- hydroxy-3-methoxy-5-methyl-benzyl)ethylenediamine; H2hmmp = 2-[(2- hydroxyethylimino)methyl]-6-methoxyphenol; Hae = 2-aminoethanol; H2L35= n-N-butyldiethanolamine; 3MeOsaltn = N, N’Bis(3-methoxy-2-oxybenzylidene)-1, 3-propanediaminato; H2L36= N, N’, N”-trimethyl-N, N”-bis(2-hydroxy-3-methoxy-5-methylbenzyl)-diethylenetriamine; H3L37= N, N’, N”-tris(2-hydroxy-3-methoxybenzilidene)-2- (aminomethyl)-2-methyl-1, 3-propanediamine; H3L38= 2-(2, 3-dihydroxpropyliminomethyl)-6-methoxyphenol. |
2014年,研究小组利用邻香兰素衍生的席夫碱配体成功合成了一个三核CoIII-DyIIISMM [Co2Ln(valdien)2(OCH3)2(chp)2] ClO45H2O (Ln = Dy (2),Tb (3),H2valdien = N1,N3-双(3-甲氧基水杨亚胺)二乙基三胺,Hchp = 6-氯-2-羟基吡啶
2014年,研究团队利用3, 5-二氯苯甲酸(HL2)作为桥联配体和2, 2'-联吡啶(bipy)作为末端双齿配体,合成了一种四核链状阳离子团簇Dy2Co2(L2)10(bipy)2(4)
2015年,Powell等人通过将配合物中的FeⅢ替换为CoⅢ,合成了配合物[DyCo(CN)6(hep)2(H2O)4] (5)
2015年,唐金魁研究组成功地将配合物中的MnⅡ替换为CoⅡ,合成了配合物[Ln2CoⅡ(C7H5O2)8] 6H2O
在2015年,由童明良团队合成了一系列线性型SMMs,[Co2Dy((L3)Br)2(H2O)] NO33H2O(7 3H2O),[Co2Dy((L3)Br)2(H2O)] NO3H2O (7 H2O),以及[Co2Dy((L3)Br)2(H2O)]NO3(7)
2018年,该研究团队合成了一个线性三核配合物,[Co2Dy(TTTTCl)2(MeOH)]NO3·3MeOH (8)
随后该团队用顺磁低自旋的[Co(CN)6]3−取代了[Fe(CN)6]3−部分,从而合成了配合物{Dy2Co}(10)
除了[Co2Dy]型配合物外,[Co2Ln2]型SMMs也是Co-Ln SMMs领域的重要组成部分。值得注意的是,Langley研究组合成了一系列[CoⅢ2Ln2]型单分子磁体。尽管有机配体有所不同,但这些配合物都保持着类似蝴蝶的核结构,表现出非凡的性能。2012年报道了三种结构相同的3d-4f配合物中,每个晶体结构都包含一个不对称单元中的两种不同分子:[LnⅢ2CoⅢ2(OMe)2(teaH)2(O2CPh)4(MeOH)4](NO3)2MeOH H2O (Ln = Gd, Tb (11a)和Dy (12a),teaH3= 三乙醇胺)和[LnⅢ2CoⅢ2(OMe)2(teaH)2(O2CPh)4(MeOH)2(NO3)2] MeOH H2O (Ln = Gd,Tb (11b)和Dy (12b)
2014年,他们用二乙醇胺(H3dea)、N-甲基二乙醇胺(H2mdea)和N-正丁基二乙醇胺)取代了H3tea (
此外,他们利用乙酰乙酸(acac)取代苯甲酸配体,得到了三个蝴蝶状的异金属配合物,分别为[Dy2CoⅢ2(OMe)2(teaH)2(acac)4(NO3)2] (16), [Dy2CoⅢ2(OH)2(teaH)2(acac)4(NO3)2]·4H2O (17)和[Dy2CoⅢ2(Om- e)2(mdea)2(acac)4(NO3)2] (18)
除了线性结构和蝴蝶型配合物外,研究人员还合成了具有其他结构的Co-Ln SMMs。基于配合物8,高松等人用CoⅢ代替CrⅢ合成了化合物{DyCo}(25)
2012年,唐金魁等人使用二硫代氧杂环二阴离子(dto2−)将[DyⅢ(HBpz3)2]2+单元(HBpz3−= 三(吡唑基)硼酸盐)与过渡金属CoⅢ组装在一起,从而合成了具有三叶螺旋桨状结构的配合物[CoDy3(HBpz3)6(dto)3] 4CH3CN 2CH2Cl2(26)
单分子磁体作为一类具有独特磁学性质的材料,吸引了研究者们广泛的研究兴趣。目前已报道的Co单分子磁体还相对较少,研究主要集中在理解磁体的磁学行为和性质,并改进合成和制备技术。通过研究发现,对Co-SMMs的调控归根到底是对其磁各向异性的调控,而其磁各向异性主要来源于基态的零场分裂,还受耦合作用的影响。现阶段已取得了一些重要的进展,但显然,我们对单分子磁体的了解还远不够,有关Co-Ln单分子磁体的研究报告没有非常全面,并且大部分Co-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。
综合以上研究进展,本文综述了不同结构类型且单分子磁体性能优异的Co-Ln单分子磁体。随着科学技术的不断进步,相信这些磁构关系不明朗、磁性行为理解片面、工业化生产困难、研究方向单一等一系列问题会被逐个解决。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,可以将Co-Ln单分子磁体纳入纳米技术中,实现更高级别的磁性控制,并用于纳米电子学和纳米磁性器件,为稀土–过渡异金属单分子磁体的应用和发展做出了重要贡献。
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,南通大学大学生创新创业训练计划项目(2024116),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: jinlizhu@ntu.edu.cn