C22H20MnN3O5, monoclinic, P121/c1 (no. 14), a = 6.5219(5) A, b = 17.793(1) A, c = 17.344(1) A, 1 = 100.664(1)°, V = 1977.8 A, Z = 4, Rgt(F) = 0.042, wRref(F) = 0.119, T = 296 K. Source of material To 20mL ethanol solution containingH2salen (0.568 g, 2mmol), Mn(OAc)3 · 2H2O (0.536 g, 2 mmol) was added slowly as solid under continuous stirring at room temperature for 2 h. Nicotinic acid (0.123 g, 1 mmol) in 5mLwater was added and the resulting mixture stirred for another 4 h.A dark brown solutionwas formed and filtrated. The filtration was left for slow evaporation. Black block-shaped crystals were obtained after 2 weeks. Discussion The chemistry ofMn complexes is of continuous interest because of their functions in biological systems, in which considerable attention has been paid to salen-type complexes [1,2]. In the title structure, the complex [Mn(salen)(nicotinato-N)(H2O)] shows a pseudo-octahedral coordination environment. The metal center Mn is coordinated by an equatorial tetradentate salen ligand and axial nicotinato N atom and a water molecule, resulting in a fac-MnN3O3 group (figure, top). The bond lengths in the title complex show the usual pattern of unequal equatorial Mn—O (1.880(2) A and 1.881(2) A) and Mn—N (1.977(2) A and 1.992(2) A) distances, which are comparable with other Mn(salen) complexes [3-5]. The elongation of axial bonds, d(Mn—Owater) = 2.246(2)A and d(Mn—Nnicotinato) = 2.353(2)A, indicates a clear evidence of Jahn-Teller distortion for high spin Mn. The trans angles are ranging from .O2–Mn1–N1 = 173.70(9)° to.O3–Mn1–N3=178.85(8)° and cis angles ranging from .N2–Mn1–N1 = 82.27(9)° to .O2–Mn1–O1 = 93.77(8)°, which suggest the larger extent distortion on basal plane than the axial position. The manganese atom is 0.035 A out of the plane defined by N1, N2, O1 and O2. A close-packed hydrogen-bonded network is formed. Water of eachmolecule acts as hydrogen bonds donors, and the oxygen atoms of nicotinato from the symmetric motifs (symmetry codes: x,+2–y,–+2+z and 2–x,+2+y,+2–z) act as hydrogen bond acceptors. So, a cyclic tetrameric motif is created with the d(H···O) = 1.88A and d(O···O) = 2.69A (figure, bottom).Eachmolecule shares two hydrogen bonds with four neighbors with theMn···Mn distances of 9.01A and 15.96A, producing a 2D network by four hydrogen bonds. Moreover, the structural packing is maintained by the C–H···& interactions, which are weaker interactions in nature but further stabilize the network. It is very interesting that the neighboring molecules interacting both byO–H···O andC–H···& interactions. Thus the cyclic C–H···& interaction rings are formed. Twokinds of non-polarC–H···& ring exist in themiddle of the polar hydrogen bond ring, which are also in the middle of the C–H···& ring. There also exist two types of C–H···Oweak hydrogen bonds. Z. Kristallogr. NCS 222 (2007) 241-242 / DOI 10.1524/ncrs.2007.0101 241 © by Oldenbourg Wissenschaftsverlag, Munchen Crystal: black block, size 0.18 × 0.23 × 0.33 mm Wavelength: Mo K0 radiation (0.71073 A) %: 7.09 cm−1 Diffractometer, scan mode: Bruker SMART CCD, #/) 2'max: 50.2° N(hkl)measured, N(hkl)unique: 9918, 3521 Criterion for Iobs, N(hkl)gt: Iobs > 2 ((Iobs), 2807 N(param)refined: 258 Programs: SHELXS-97 [7], SHELXL-97 [8], SHELXTL [9] Table 1. Data collection and handling.