A heterotrimetallic Cu–Co–Zn complex with the 2,2′-iminodiethanol ligand

The crystal structure of the title compound, triacetato-1κO;3κ⁴O,O′-(2,2′-imino­diethanol)-1κ³O,N,O′-bis­(μ-2,2′-iminodi­ethanol­ato)-1κ²O:2κ⁶O,N,O′:3κ²O′-cobalt(III)copper(II)zinc(II), [CoCuZn(C₄H₉NO₂)₂(C₂H₃O₂)₃(C₄H₁₁NO₂)], shows a mol­ecule with a triangular three-metal core. The metal sites were refined with full occupancies, but the possibility that the Zn and Cu positions are actually mixed Cu/Zn sites cannot be excluded. The inter­metallic Cu...Co and Co...Zn distances are 2.924 (3) and 2.906 (3) Å, respectively. The neutral mol­ecules are held together by N—H...O hydrogen bonds involving amine groups from the 2,2′-iminodiethanol ligands and acetate groups to build two-dimensional layers.

S1. Comment

The coordination chemistry of heterometallic complexes of transition metals is currently an active and rapidly expanding research area. Special effort has been focused on the preparation and characterization of heterotrimetallic complexes, for example Cu/Co/Ni (Nesterov et al., 2004), Cu/Fe/Gd (Gheorghe et al., 2003) or Co/Fe/Ni (Berlinguette & Dunbar, 2005). Such interest is a result of the many potential applications of these complexes as, for instance, molecular magnets (Liu et al., 2004; Verani et al., 2000) or catalysts (Becker et al., 2001). We have recently reported the first Cu/Co/Zn heterotrimetallic complexes, containing a trinuclear CuCoZnO₄ core, which could be viewed as a distorted cube in which one corner site is vacant (Nesterov et al., 2005). We report here the preparation and crystal structure of the new heterotrimetallic complex [CuCoZn(L)₂(H₂L)(OAc)₃], (I), of a different type; the trinuclear CuCoZnO₁₁N₃ core now represents a triangle with a Cu···Co···Zn angle of 107.6 (1)° (Fig. 1). The metal atoms are bridged through the O atoms from the deprotonated diethanolamine ligand (H₂L). A similar molecular geometry was observed in the Cu/Co/Cd compound with the same ligand (Nesterov et al., 2004) but different anions.

Selected bond distances are given in Table 1. The Cu atom is in an O₅N tetragonally distorted octahedral environment with axial lengths equal to 2.595 (15) and 2.345 (14) Å (atoms O5 and O6, respectively). One of the equatorial positions is occupied by the O atom of the acetate anion. The Co atom has an almost regular octahedral arrangement with Co—O(N) distances ranging from 1.884 (10) to 1.943 (15) Å and trans-angles from 167.5 (5) to 177.4 (5)°. Such geometry is typical of a six-coordinated low-spin cobalt(III) ion (Wells, 1986). The Zn atom displays a distorted tetrahedral environment with an O₄ chromophore. The two acetate groups exhibit monodentate coordination. However, considering the Zn—O10 and Zn—O12 distances [2.491 (16) and 2.780 (17) Å, respectively], the presence of weak bonding between the metal atom and uncoordinated acetate O atoms can be presumed.

The molecules form a two-dimensional network involving H atoms from the aminoalcohol ligands (Fig. 2). Atom O8 participates in both inter- (O5—H5O···O8) and intramolecular (N3—H3···O8ⁱⁱ) hydrogen contacts (see Table 2). Two other intermolecular hydrogen bonds involve amine and acetate groups.

S2. Experimental

Copper powder (0.16 g, 2.5 mmol), Co(OAc)₂·4H₂O (0.62 g, 2.5 mmol), Zn(OAc)₂·2H₂O (0.55 g, 2.5 mmol), dimethylsulfoxide (20 ml) and diethanolamine (2 ml) were heated to 323–333 K and stirred magnetically until total dissolution of the copper was observed (1 h). Dark-green crystals suitable for X-ray analysis were obtained from the dark-green solution after successive addition of a PrⁱOH/diethyl ether (1:3) mixture. The crystals were filtered off, washed with dry PrⁱOH and finally dried in vacuo at room temperature. Yield 0.9 g, 53% (per copper). Analysis found: C 31.7, H 5.5, Co 8.6, Cu 9.0, N 6.2, Zn 9.9%; calculated: C 31.96, H 5.66, Co 8.71, Cu 9.39, N 6.21, Zn 9.67%. IR (KBr, cm⁻¹): 1600 [ν_as(COO)], 1580 [ν_as(COO)], 1455 [ν_s(COO)].#######################

S3. Refinement

In general, the non-H atoms were refined anisotropically. The assignment of Cu and Co atoms was largely achieved on refinement and coordination geometry. The third metal atom was assigned as Zn from the analytical data. It has distorted tetrahedral environment with two longer bonds to the other two O atoms (O10 and O12) of the acetate groups. This geometry is unusual not only for zinc but also for copper. Although elemental analysis suggested the absence of metal scrambling within a molecule, taking into account the refinement the possibility that both the Zn and the Cu positions are mixed Cu/Zn cannot be excluded. Two diethanolamine ligands have both O atoms bridging and hence –OH groups were assigned as deprotonated. From the interatomic distances in the O6···O4 and O5···O8 atom pairs [2.631 (16) and 2.625 (18) Å, respectively], two strong intramolecular hydrogen bonds (O6—H6O···O4 and O5—H5O···O8) can be identified; the H atoms were located on atoms O5 and O6. Other H atoms were placed at idealized positions [C—H = 0.92–1.00 Å, U_iso(H) = 1.25U_eq(C) for CH₂ and 1.5U_eq(C) for CH₃] Please check and not refined. The C—O bonds of the acetates are indicative of carboxylate but not carboxylic acid groups [C—O bonds range from 1.21 (3)–1.30 (3) Å]. Acetate atom C18 was refined with isotropic displacement parameters. Attempts to refine this atom as disordered did not improve the model. All bond distances and angles within the aminoalcohol and acetate ligands are as expected.

Computing details

Data collection: SMART (Siemens, 1995); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT; program(s) used to solve structure: Xtal3.5 (Hall et al., 1995); program(s) used to refine structure: CRYLSQ in Xtal3.5; molecular graphics: Xtal3.5; software used to prepare material for publication: BONDLA and CIFIO in Xtal3.5.

Figures

	Fig. 1. Molecular structure of (I), with the numbering scheme (the non-H atoms are shown as 50% probability displacement ellipsoids).
	Fig. 2. The hydrogen-bonding scheme of (I). The H atoms of the CH2 groups have been omitted for clarity. [Symmetry codes: (i) −x + 1, y + 1/2, −z + 1; (ii) −x + 2, y − 1/2, −z + 2; (iii) −x + 1, y − 1/2, −z + 1; (iv) −x + 2, y + 1/2, −z + 2.]

triacetato-1κO,3κ⁴O,O'-(2,2'-iminodiethanol)-1κ²O,O'-bis(2,2'- iminodiethanolato)-1κ²O:2κ⁶O,N,O':3κ²O'-cobalt(III)copper(II)zinc(II)

Crystal data

[CuCoZn(C4H9NO2)2(C2H3O2)3(C4H11NO2)]	F(000) = 698
Mr = 676.45	Dx = 1.734 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: p 2yb	Cell parameters from 2451 reflections
a = 8.353 (3) Å	θ = 2.3–26.1°
b = 12.357 (4) Å	µ = 2.43 mm^−1
c = 12.934 (4) Å	T = 150 K
β = 103.916 (5)°	Fragment, dark-green
V = 1295.8 (7) Å^3	0.14 × 0.09 × 0.06 mm
Z = 2

Data collection

Bruker SMART CCD diffractometer	5068 independent reflections
Radiation source: sealed tube	3927 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.062
ω scans	θmax = 26.3°, θmin = 1.6°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→10
Tmin = 0.62, Tmax = 0.86	k = −15→15
11690 measured reflections	l = −16→16

Refinement

Refinement on F	0 constraints
Least-squares matrix: full	H-atom parameters not refined
R[F^2 > 2σ(F^2)] = 0.065	w = 1/[σ^2(F) + 0.001F^2]
wR(F^2) = 0.092	(Δ/σ)max = 0.001
S = 1.33	Δρmax = 1.07 e Å^−3
3927 reflections	Δρmin = −0.74 e Å^−3
316 parameters	Absolute structure: Flack (1983), 3212 Friedel pairs
0 restraints	Absolute structure parameter: 0.05 (5)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Zn	0.7775 (3)	0.5000 (2)	0.98433 (16)	0.0251 (10)
Cu	0.4964 (2)	0.3611 (2)	0.65139 (15)	0.0171 (8)
Co	0.7503 (2)	0.3132 (2)	0.84472 (16)	0.0156 (10)
O1	0.7102 (12)	0.4248 (9)	0.7401 (9)	0.017 (5)
O2	0.9158 (14)	0.3839 (10)	0.9509 (9)	0.023 (6)
O3	0.5942 (12)	0.2387 (11)	0.7393 (7)	0.018 (5)
O4	0.6012 (13)	0.3837 (9)	0.9148 (9)	0.019 (5)
O5	0.5972 (15)	0.3368 (10)	0.4781 (11)	0.033 (7)
O6	0.3502 (15)	0.4469 (10)	0.7619 (9)	0.026 (6)
O7	0.2839 (14)	0.2883 (9)	0.5823 (9)	0.024 (6)
O8	0.3635 (15)	0.1906 (10)	0.4568 (10)	0.026 (6)
O9	0.6785 (17)	0.6325 (12)	0.9126 (11)	0.035 (7)
O10	0.9371 (15)	0.6352 (13)	0.9071 (12)	0.040 (7)
O11	0.7546 (16)	0.4889 (13)	1.1336 (11)	0.040 (7)
O12	1.0163 (19)	0.5344 (13)	1.1721 (16)	0.057 (10)
N1	0.9271 (15)	0.2649 (13)	0.7856 (10)	0.019 (6)
N2	0.7423 (15)	0.1900 (12)	0.9367 (11)	0.019 (6)
N3	0.4346 (16)	0.5012 (13)	0.5678 (10)	0.021 (6)
C1	0.843 (2)	0.4339 (14)	0.6867 (14)	0.023 (7)
C2	0.909 (2)	0.3203 (17)	0.6800 (13)	0.026 (7)
C3	1.0900 (18)	0.2885 (14)	0.8631 (11)	0.020 (7)
C4	1.0734 (19)	0.3923 (14)	0.9226 (14)	0.022 (6)
C5	0.507 (2)	0.1577 (14)	0.7869 (15)	0.028 (9)
C6	0.637 (2)	0.1049 (16)	0.8734 (16)	0.029 (9)
C7	0.6846 (18)	0.2301 (15)	1.0298 (12)	0.021 (8)
C8	0.551 (2)	0.3163 (16)	0.9930 (13)	0.025 (8)
C9	0.538 (2)	0.4311 (17)	0.4209 (15)	0.031 (10)
C10	0.395 (2)	0.4818 (14)	0.4515 (13)	0.024 (8)
C11	0.298 (2)	0.5527 (15)	0.6027 (14)	0.024 (8)
C12	0.336 (2)	0.5573 (17)	0.7247 (15)	0.031 (9)
C13	0.257 (2)	0.2238 (12)	0.5030 (14)	0.024 (8)
C14	0.078 (3)	0.185 (2)	0.4634 (19)	0.049 (13)
C15	0.801 (3)	0.6756 (16)	0.8822 (15)	0.034 (9)
C16	0.763 (3)	0.7737 (19)	0.8131 (17)	0.047 (12)
C17	0.893 (2)	0.5020 (19)	1.1959 (15)	0.034 (9)
C18	0.908 (5)	0.485 (3)	1.310 (3)	0.090 (10)*
H5O	0.56327	0.26901	0.44958	0.03900*
H6O	0.40826	0.44398	0.83241	0.02800*
H1	0.91687	0.18974	0.77516	0.02800*
H2	0.84774	0.16177	0.96039	0.03000*
H3	0.52279	0.55005	0.58486	0.02900*
H1a	0.79819	0.46469	0.61666	0.03200*
H1b	0.92398	0.48172	0.72511	0.03200*
H2a	1.01213	0.32611	0.66194	0.03500*
H2b	0.83357	0.28211	0.62460	0.03500*
H3a	1.11970	0.22963	0.91258	0.02200*
H3b	1.17345	0.29606	0.82489	0.02200*
H4a	1.07614	0.45231	0.87849	0.02600*
H4b	1.16252	0.39698	0.98497	0.02600*
H5a	0.42226	0.19367	0.81781	0.03700*
H5b	0.44802	0.10800	0.73563	0.03700*
H6a	0.69757	0.05706	0.84119	0.03600*
H6b	0.58267	0.06324	0.91907	0.03600*
H7a	0.64065	0.17233	1.06183	0.03000*
H7b	0.77468	0.26190	1.08103	0.03000*
H8a	0.53897	0.35913	1.05166	0.03500*
H8b	0.44929	0.28262	0.96104	0.03500*
H9a	0.62970	0.48365	0.43158	0.04000*
H9b	0.51036	0.41561	0.34549	0.04000*
H10a	0.30448	0.43548	0.43279	0.03700*
H10b	0.36933	0.54992	0.41498	0.03700*
H11a	0.27536	0.62309	0.57433	0.03400*
H11b	0.19849	0.50917	0.57724	0.03400*
H12a	0.24787	0.59176	0.74857	0.03800*
H12b	0.43478	0.59525	0.75218	0.03800*
H14a	0.00568	0.23104	0.49277	0.07400*
H14b	0.06391	0.11384	0.47912	0.07400*
H14c	0.04486	0.19487	0.38685	0.07400*
H16a	0.75537	0.83157	0.86120	0.05300*
H16b	0.65290	0.76162	0.76916	0.05300*
H16c	0.83805	0.78279	0.77239	0.05300*
H18a	0.91563	0.55242	1.34698	0.1200*
H18b	1.00116	0.44183	1.34163	0.1200*
H18c	0.81135	0.44780	1.32069	0.1200*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn	0.0191 (10)	0.0265 (11)	0.0287 (11)	−0.0009 (9)	0.0036 (8)	−0.0055 (9)
Cu	0.0122 (9)	0.0186 (9)	0.0188 (10)	−0.0005 (8)	0.0004 (7)	0.0016 (8)
Co	0.0110 (10)	0.0165 (11)	0.0188 (11)	0.0008 (8)	0.0026 (8)	0.0023 (9)
O1	0.004 (5)	0.015 (6)	0.027 (6)	−0.001 (4)	−0.002 (4)	0.001 (5)
O2	0.017 (6)	0.022 (7)	0.030 (7)	0.002 (5)	0.006 (5)	−0.004 (5)
O3	0.011 (5)	0.026 (6)	0.017 (5)	−0.005 (5)	0.003 (4)	−0.001 (5)
O4	0.015 (6)	0.021 (6)	0.019 (6)	−0.001 (5)	0.001 (4)	−0.000 (5)
O5	0.019 (6)	0.020 (7)	0.052 (8)	−0.003 (5)	−0.007 (6)	−0.004 (6)
O6	0.027 (7)	0.027 (7)	0.023 (6)	−0.003 (5)	0.004 (5)	0.003 (5)
O7	0.014 (6)	0.032 (7)	0.027 (6)	−0.003 (5)	0.007 (5)	0.000 (5)
O8	0.022 (6)	0.023 (6)	0.030 (7)	0.001 (5)	0.002 (5)	−0.004 (5)
O9	0.035 (8)	0.032 (8)	0.038 (8)	−0.011 (6)	0.010 (6)	−0.005 (6)
O10	0.017 (7)	0.046 (9)	0.051 (9)	0.008 (6)	−0.004 (6)	−0.013 (7)
O11	0.030 (8)	0.048 (9)	0.037 (8)	0.004 (7)	−0.000 (6)	−0.008 (7)
O12	0.027 (8)	0.042 (10)	0.108 (14)	−0.003 (7)	0.033 (9)	−0.001 (9)
N1	0.013 (5)	0.024 (8)	0.018 (6)	−0.008 (4)	0.001 (5)	−0.003 (6)
N2	0.007 (6)	0.023 (7)	0.024 (8)	0.003 (5)	0.001 (5)	0.002 (6)
N3	0.011 (6)	0.031 (8)	0.018 (7)	0.009 (6)	−0.004 (5)	0.007 (6)
C1	0.012 (4)	0.023 (9)	0.033 (9)	−0.008 (4)	0.007 (7)	0.002 (7)
C2	0.009 (4)	0.050 (11)	0.021 (8)	0.005 (8)	0.007 (6)	0.011 (8)
C3	0.010 (5)	0.037 (10)	0.011 (7)	0.002 (6)	−0.003 (6)	0.007 (6)
C4	0.008 (4)	0.024 (9)	0.029 (9)	0.006 (6)	−0.003 (6)	0.006 (7)
C5	0.028 (9)	0.013 (9)	0.040 (11)	−0.010 (7)	0.003 (8)	−0.000 (7)
C6	0.020 (9)	0.035 (10)	0.035 (11)	−0.010 (8)	0.010 (8)	0.009 (8)
C7	0.012 (7)	0.030 (10)	0.019 (8)	−0.005 (7)	0.000 (6)	−0.002 (7)
C8	0.024 (9)	0.028 (9)	0.023 (9)	0.009 (8)	0.005 (7)	0.005 (8)
C9	0.022 (9)	0.037 (11)	0.034 (11)	0.014 (9)	0.005 (8)	0.008 (9)
C10	0.023 (9)	0.021 (9)	0.026 (9)	−0.005 (7)	0.002 (7)	0.003 (7)
C11	0.010 (8)	0.028 (9)	0.033 (10)	0.010 (7)	0.006 (7)	0.009 (8)
C12	0.015 (9)	0.045 (12)	0.030 (10)	−0.003 (8)	0.001 (7)	−0.007 (9)
C13	0.024 (9)	0.013 (9)	0.033 (10)	0.004 (7)	0.004 (7)	0.007 (7)
C14	0.032 (12)	0.055 (15)	0.064 (15)	−0.018 (11)	0.017 (11)	−0.043 (13)
C15	0.047 (13)	0.020 (9)	0.027 (10)	−0.009 (9)	−0.001 (9)	−0.012 (8)
C16	0.065 (15)	0.038 (14)	0.038 (11)	0.003 (11)	0.011 (10)	0.010 (10)
C17	0.027 (10)	0.044 (11)	0.032 (10)	−0.001 (9)	0.009 (8)	−0.007 (9)

Bond lengths (Å)

Zn—O2	1.954 (12)	C1—H1a	0.970
Zn—O4	2.099 (11)	C1—H1b	0.947
Zn—O9	1.964 (14)	C2—H2a	0.944
Zn—O10	2.491 (16)	C2—H2b	0.959
Zn—O11	1.990 (14)	C3—C4	1.52 (2)
Zn—O12	2.780 (17)	C3—H3a	0.961
Cu—O1	2.034 (10)	C3—H3b	0.951
Cu—O3	1.950 (12)	C4—H4a	0.940
Cu—O5	2.595 (15)	C4—H4b	0.959
Cu—O6	2.345 (14)	C5—C6	1.51 (2)
Cu—O7	2.000 (11)	C5—H5a	1.00
Cu—N3	2.041 (16)	C5—H5b	0.950
Co—O1	1.905 (11)	C6—H6a	0.94
Co—O2	1.910 (11)	C6—H6b	0.97
Co—O3	1.884 (10)	C7—C8	1.53 (2)
Co—O4	1.917 (12)	C7—H7a	0.943
Co—N1	1.915 (14)	C7—H7b	0.959
Co—N2	1.943 (15)	C8—H8a	0.951
O1—C1	1.44 (2)	C8—H8b	0.947
O2—C4	1.45 (2)	C9—C10	1.49 (3)
O3—C5	1.46 (2)	C9—H9a	0.99
O4—C8	1.45 (2)	C9—H9b	0.97
O5—C9	1.40 (2)	C10—H10a	0.934
O5—H5O	0.931	C10—H10b	0.964
O6—C12	1.44 (2)	C11—C12	1.53 (3)
O6—H6O	0.925	C11—H11a	0.945
O7—C13	1.27 (2)	C11—H11b	0.975
O8—C13	1.25 (2)	C12—H12a	0.97
O9—C15	1.30 (3)	C12—H12b	0.940
O10—C15	1.21 (2)	C13—C14	1.54 (3)
O11—C17	1.25 (2)	C14—H14a	0.97
O12—C17	1.21 (3)	C14—H14b	0.92
N1—C2	1.50 (2)	C14—H14c	0.97
N1—C3	1.512 (18)	C15—C16	1.50 (3)
N1—H1	0.939	C16—H16a	0.96
N2—C6	1.49 (2)	C16—H16b	0.97
N2—C7	1.49 (2)	C16—H16c	0.92
N2—H2	0.928	C17—C18	1.47 (4)
N3—C10	1.48 (2)	C18—H18a	0.96
N3—C11	1.47 (2)	C18—H18b	0.95
N3—H3	0.936	C18—H18c	0.96
C1—C2	1.52 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O6—H6O···O4	0.93	1.86	2.631 (16)	139
O5—H5O···O8	0.93	1.95	2.625 (18)	128
N1—H1···O12^i	0.94	2.07	2.92 (2)	150
N2—H2···O10^i	0.93	2.19	3.02 (2)	148
N3—H3···O8^ii	0.94	2.11	2.95 (2)	148

Symmetry codes: (i) −x+2, y−1/2, −z+2; (ii) −x+1, y+1/2, −z+1.