TY - JOUR
T1 - Monomeric, trimeric, and tetrameric transition metal complexes (Mn, Fe, Co) containing N,N-bis(2-pyridylmethyl)-2-aminoethanol/-ate
T2 - preparation, crystal structure, molecular magnetism and oxidation catalysis
AU - Shin, Jong Won
AU - Rowthu, Sankara Rao
AU - Hyun, Min Young
AU - Song, Young Joo
AU - Kim, Cheal
AU - Kim, Bong Gon
AU - Min, Kil Sik
PY - 2011/6/7
Y1 - 2011/6/7
N2 - The reaction of N,N-bis(2-pyridylmethyl)-2-aminoethanol (bpaeOH), NaSCN/NaN3, and metal (M) ions [M = Mn(ii), Fe(ii/iii), Co(ii)] in MeOH, leads to the isolation of a series of monomeric, trimeric, and tetrameric metal complexes, namely [Mn(bpaeOH)(NCS)2] (1), [Mn(bpaeO)(N 3)2] (2), [Fe(bpaeOH)(NCS)2] (3), [Fe 4(bpaeO)2(CH3O)2(N3) 8] (4), [Co(bpaeOH)(NCS)2] (5), and [Co 3(bpaeO)2(NO3)(N3) 4](NO3) (6). These compounds have been investigated by single crystal X-ray diffractometry and magnetochemistry. In complex 1 the Mn(ii) is bonded to one bpaeOH and two thiocyanate ions, while in complex 2 it is coordinated to a deprotonated bpaeO- and two azide ions. The oxidation states of manganese ions are 2+ for 1 and 3+ for 2, respectively, indicating that the different oxidation states depend on the type of binding anions. The structures of monomeric iron(ii) and cobalt(ii) complexes 3 and 5 with two thiocyanate ions are isomorphous to that of 1. Compounds 1, 2, 3, and 5 exhibit high-spin states in the temperature range 5 to 300 K. 4 contains two different iron(iii) ions in an asymmetric unit, one is coordinated to a deprotonated bpaeO-, an azide ion, and a methoxy group, and the other is bonded to three azide ions and two oxygens from bpaeO- and a methoxy group. Two independent iron(iii) ions in 4 form a tetranuclear complex by symmetry. 4 displays both ferromagnetic and antiferromagnetic couplings (J = 9.8 and -14.3 cm-1) between the iron(iii) ions. 6 is a mixed-valence trinuclear cobalt complex, which is formulated as CoIII(S = 0)-CoII(S = 3/2)-CoIII(S = 0). The effective magnetic moment at room temperature corresponds to the high-spin cobalt(ii) ion (∼4.27 μB). Interestingly, 6 showed efficient catalytic activities toward various olefins and alcohols with modest to excellent yields, and it has been proposed that a high-valent CoV-oxo species might be responsible for oxygen atom transfer in the olefin epoxidation and alcohol oxidation reactions.
AB - The reaction of N,N-bis(2-pyridylmethyl)-2-aminoethanol (bpaeOH), NaSCN/NaN3, and metal (M) ions [M = Mn(ii), Fe(ii/iii), Co(ii)] in MeOH, leads to the isolation of a series of monomeric, trimeric, and tetrameric metal complexes, namely [Mn(bpaeOH)(NCS)2] (1), [Mn(bpaeO)(N 3)2] (2), [Fe(bpaeOH)(NCS)2] (3), [Fe 4(bpaeO)2(CH3O)2(N3) 8] (4), [Co(bpaeOH)(NCS)2] (5), and [Co 3(bpaeO)2(NO3)(N3) 4](NO3) (6). These compounds have been investigated by single crystal X-ray diffractometry and magnetochemistry. In complex 1 the Mn(ii) is bonded to one bpaeOH and two thiocyanate ions, while in complex 2 it is coordinated to a deprotonated bpaeO- and two azide ions. The oxidation states of manganese ions are 2+ for 1 and 3+ for 2, respectively, indicating that the different oxidation states depend on the type of binding anions. The structures of monomeric iron(ii) and cobalt(ii) complexes 3 and 5 with two thiocyanate ions are isomorphous to that of 1. Compounds 1, 2, 3, and 5 exhibit high-spin states in the temperature range 5 to 300 K. 4 contains two different iron(iii) ions in an asymmetric unit, one is coordinated to a deprotonated bpaeO-, an azide ion, and a methoxy group, and the other is bonded to three azide ions and two oxygens from bpaeO- and a methoxy group. Two independent iron(iii) ions in 4 form a tetranuclear complex by symmetry. 4 displays both ferromagnetic and antiferromagnetic couplings (J = 9.8 and -14.3 cm-1) between the iron(iii) ions. 6 is a mixed-valence trinuclear cobalt complex, which is formulated as CoIII(S = 0)-CoII(S = 3/2)-CoIII(S = 0). The effective magnetic moment at room temperature corresponds to the high-spin cobalt(ii) ion (∼4.27 μB). Interestingly, 6 showed efficient catalytic activities toward various olefins and alcohols with modest to excellent yields, and it has been proposed that a high-valent CoV-oxo species might be responsible for oxygen atom transfer in the olefin epoxidation and alcohol oxidation reactions.
UR - http://www.scopus.com/inward/record.url?scp=79957476606&partnerID=8YFLogxK
U2 - 10.1039/c1dt10028a
DO - 10.1039/c1dt10028a
M3 - Article
C2 - 21523305
AN - SCOPUS:79957476606
SN - 1477-9226
VL - 40
SP - 5762
EP - 5773
JO - Dalton Transactions
JF - Dalton Transactions
IS - 21
ER -