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Electronic Supplementary Information

A 3D CoII framework with alternating vertex- and edge-sharing Δ-ribbon showing a two-step

field-induced metamagnetic transition

En-Cui Yang*, Zhong-Yi Liu, Xiao-Yun Wu, and Xiao-Jun Zhao*

Synthesis of 1: A mixture containing CoCl2·6H2O (47.6 mg, 0.2 mmol), 1,2,3-benzenetricarboxylic acid (42.0

mg, 0.2 mmol), and 5-amino-1H-tetrazole (20.6 mg, 0.2 mmol) was dissolved in doubly deionized water (12.0

mL), and the initial pH value of the mixture was adjusted to ca. 4.0 by aqueous ammonia. The mixture was then

transferred into a parr Teflon-lined stainless steel vessel (23.0 mL) and heated to 200 oC for 24 h under

autogenous pressure. After the mixture was cooled to room temperature, red block-shaped crystals suitable for

X-ray analysis were generated directly, washed with ethanol and dried in air. Yield: 48.9% based on CoII salt.

Calc. for C17H19Co3.5N5O13.5 1: C 28.53, H 2.68, N 9.79%. Found: C 28.51, H 2.72, N 9.75%. IR (KBr, cm–1):

3476(br), 3367(w), 3072(w), 1606(s), 1562(s), 1480(w), 1454(w), 1412(s), 1391(s), 1359(s), 1268(w), 1157(w),

1081(w), 888(w), 749(m), 711(m), 653(w), 533(w), 416(w).

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Fig. S1. TG curve for 1.

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Fig. S2. Simulated and experimental X-ray powder diffraction patterns for 1.

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Table S1. Selected bond lengths and angles in 1 (Å, º).

Co(1)–O(1)#1 2.018(3) Co(1)–O(10) 2.043(3)

Co(1)–O(11) 2.066(3) Co(1)–O(3)#2 2.105(3)

Co(1)–N(1) 2.132(3) Co(1)–O(8)#3 2.288(3)

Co(2)–O(10)#1 2.083(3) Co(2)–O(4)#2 2.099(3)

Co(2)–O(10) 2.107(3) Co(2)–N(2)#1 2.132(3)

Co(2)–O(9) 2.158(3) Co(2)–O(2) 2.176(3)

Co(3)–N(3)#4 2.045(3) Co(3)–O(9) 2.122(3)

Co(3)–O(7)#5 2.116(3) Co(4)–O(6) 2.164(3)

Co(4)–O(9) 2.061(3) Co(4)–O(8)#3 2.096(3)

Co(4)–O(3)#2 2.127(3) Co(4)–N(4)#4 2.135(3)

Co(4)–O(5) 2.148(3)

O(1)#1–Co(1)–O(10) 89.01(12) O(1)#1–Co(1)–O(11) 88.41(14)

O(10)–Co(1)–O(11) 171.91(15) O(1)#1–Co(1)–O(3)#2 172.86(12)

O(10)–Co(1)–O(3)#2 94.72(10) O(11)–Co(1)–O(3)#2 87.07(13)

O(1)#1–Co(1)–N(1) 95.58(14) O(10)–Co(1)–N(1) 92.84(11)

O(11)–Co(1)–N(1) 95.04(16) O(3)#2–Co(1)–N(1) 90.31(12)

O(1)#1–Co(1)–O(8)#3 96.05(12) O(10)–Co(1)–O(8)#3 86.68(10)

O(11)–Co(1)–O(8)#3 85.97(15) O(3)#2–Co(1)–O(8)#3 78.13(10)

N(1)–Co(1)–O(8)#3 168.34(12) O(10)#1–Co(2)–O(4)#2 98.15(11)

O(10)#1–Co(2)–O(10) 80.73(11) O(4)#2–Co(2)–O(10) 92.43(11)

O(10)#1–Co(2)–N(2)#1 83.85(11) O(4)#2–Co(2)–N(2)#1 176.47(13)

O(10)–Co(2)–N(2)#1 90.75(11) O(10)#1–Co(2)–O(9) 165.43(10)

O(4)#2–Co(2)–O(9) 92.78(11) O(10)–Co(2)–O(9) 89.25(10)

N(2)#1–Co(2)–O(9) 85.75(11) O(10)#1–Co(2)–O(2) 93.56(10)

O(4)#2–Co(2)–O(2) 83.79(11) O(10)–Co(2)–O(2) 172.67(11)

N(2)#1–Co(2)–O(2) 93.21(12) O(9)–Co(2)–O(2) 97.19(11)

N(3)#4–Co(3)–N(3)#1 180.0 N(3)#4–Co(3)–O(7)#5 92.03(13)

N(3)#1–Co(3)–O(7)#5 87.97(13) N(3)#4–Co(3)–O(7)#3 87.97(13)

N(3)#1–Co(3)–O(7)#3 92.03(13) O(7)#5–Co(3)–O(7)#3 180.00(6)

N(3)#4–Co(3)–O(9) 90.61(12) N(3)#1–Co(3)–O(9) 89.39(12)

O(7)#5–Co(3)–O(9) 88.66(11) O(7)#3–Co(3)–O(9) 91.33(11)

N(3)#4–Co(3)–O(9)#6 89.39(12) N(3)#1–Co(3)–O(9)#6 90.61(12)

O(7)#5–Co(3)–O(9)#6 91.34(11) O(7)#3–Co(3)–O(9)#6 88.66(11)

O(9)–Co(3)–O(9)#6 179.999(1) O(9)–Co(4)–O(8)#3 98.31(11)

O(9)–Co(4)–O(3)#2 96.82(10) O(8)#3–Co(4)–O(3)#2 82.05(11)

O(9)–Co(4)–N(4)#4 93.90(11) O(8)#3–Co(4)–N(4)#4 85.79(12)

O(3)#2–Co(4)–N(4)#4 164.82(12) O(9)–Co(4)–O(5) 95.37(11)

O(8)#3–Co(4)–O(5) 163.03(11) O(3)#2–Co(4)–O(5) 86.41(11)

N(4)#4–Co(4)–O(5) 103.29(13) O(9)–Co(4)–O(6) 155.69(11)

O(8)#3–Co(4)–O(6) 106.00(11) O(3)#2–Co(4)–O(6) 87.14(11)

N(4)#4–Co(4)–O(6) 87.50(12) O(5)–Co(4)–O(6) 60.83(11)

Symmetry code: #1 – x, 1 – y, 1 – z; #2 x, 3/2 – y, 1/2 + z; #3 1 – x, y – 1/2, 3/2 – z; #4 x + 1, y, z; #5 x, 3/2 – y, z – 1/2; #6 1 – x, 1 – y, 1 – z.

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geometrical parameters pathway magnetic bridges

J1 μ3-OH, μ4-atz, μ2-syn,syn-COO-

J2 μ3-OH, μ4-atz

J3 μ3-OH, μ2-syn,syn-COO-

J4 μ2-COO-, μ2-COO- (single-atom-O bridges)

J5 μ3-OH, μ2-syn,syn-COO-

J6 μ3-OH, μ3-OH

J7 μ3-OH, μ2-syn,syn-COO-, μ4-atz

Fig. S3. Scheme of the Δ-ribbon topology, the superexchange pathways, and the geometrical structural parameters

for the triangles of 1.

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Fig. S4. (a) Perpendicular ribbons of edge- and vertex-sharing Δ-ribbon in 1 linked by two ip2- bridges. (b)

Coordination modes of ip2- ligands.

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Fig. S5. Plot of χMT and χM-1 vs T for 1 under an applied magnetic field of 0.5 KOe (The solid straight lines is

corresponding to the best fit).

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Fig. S6. Temperature-dependent ac susceptibility recorded under a zero Oe dc field and a 3.5 Oe ac field at

various frequencies.

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