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The crystal structure of the title compound, C24H24N4O3, is dominated by one bifurcated intramolecular and two intermolecular hydrogen bonds. This demonstrates the flexible nature of the organic mol­ecule and the strong tendency of carbox­amide groups to form hydrogen bonds.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801015781/ob6075sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536801015781/ob6075Isup2.hkl
Contains datablock I

CCDC reference: 175994

Key indicators

  • Single-crystal X-ray study
  • T = 91 K
  • Mean [sigma](C-C) = 0.006 Å
  • R factor = 0.067
  • wR factor = 0.239
  • Data-to-parameter ratio = 31.6

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry


Red Alert Alert Level A:
TYPE_049 Alert A _diffrn_reflns_number is not of type numb.
Author response: I have given the number of reflections for each of two twin components, separated by a comma.
REFLT_03
         From the CIF: _diffrn_reflns_theta_max           30.50
         From the CIF: _reflns_number_total               8879
         TEST2: Reflns within _diffrn_reflns_theta_max
         Count of symmetry unique reflns         6200
         Completeness (_total/calc)            143.21%
          Alert A: > 15% excess reflns - sys abs data present?
Author response: The excess reflns represent the contributions from the two twin components.

Amber Alert Alert Level B:
REFLT_01 Alert B The number of symmetry-independent reflections cannot exceed the total number of reflections measured Number of symmetry-independent reflections = 8879 Total number of reflections = 7955
Author response: The total number of reflections is based on the unique reflections for both twin components.

2 Alert Level A = Potentially serious problem
1 Alert Level B = Potential problem
0 Alert Level C = Please check

Comment top

The synthesis of new tripodal ligands with amidate groups that are based upon the tris(2-aminoethyl)amine unit has received attention in recent years due to their ability to complex Mn+ ions (Macbeth et al., 2000). Incorporation of amidate linkages within a tripodal ligand has also been utilized to develop tris-catecholate enterobactin analogues (Cohen et al., 2000). In addition, a variety of ligands designed to stabilize anion coordination are based in part on tripodal frames and utilize hydrogen-bond networks from amido groups to stabilize the ligand–anion interaction (Schmidtchen, 1997). The common synthetic route of coupling a carboxylic acid groups with primary amines via the use of triphenyl phosphite has been utilized here to afford the title compound, (I), in high yield.

The molecular structure of (I) is presented in Fig. 1. The three tripodal arms of the ligand are extended, in spite of the intramolecular hydrogen bonding involving the amide N1—H1 group and both N4 and O3. Additional hydrogen bonding is depicted in Fig. 2. The amide N3—H3 group forms a centrosymmetrically related pair of hydrogen bonds between H3 and O2'. The amide N2—H2 group hydrogen bonds to O1'' in a molecule translated along a.

It is interesting to note that the similar molecule tris[2-(benzoylamino)ethyl]amine, (II), has recently been reported (Goldcamp et al., 2000). In its structure, the molecule adopts a folded conformation that contrasts with the extended arrangement of (I) (Fig. 3). It also has an intramolecular hydrogen bond between a carboxamido N—H group of one arm of the tripodal ligand and a carbonyl O atom of a second carboxamide group. The difference in the tripodal unit of (II) compared to (I) is a simple rearrangement of the carboxamide units. Compound (II) is obtained from the reaction between tris(2-aminoethyl)amine and benzoic acid, while (I) is synthesized from nitrilotriacetic acid and aniline. The comparable intramolecular N—H···O hydrogen bond is part of an eight-membered ring in (I), while it is a ten-membered ring in (II). This slight change appears to have a profound effect on the structure of the resulting molecule, although other crystal-packing effects probably play a role. However, this may have implications in the development of molecular motifs that are specifically designed to stabilize a pre-formed molecular structure.

Experimental top

The title compound, (I), was synthesized via the coupling reaction of nitrilotriacetic acid and aniline in the presence of triphenyl phosphite using pyridine as the solvent. A mixture of 3.04 g of nitrilotriacetic acid (15.9 mmol), 4.44 g of aniline (47.7 mmol) and 14.81 g of triphenyl phosphite (47.7 mmol) in 25 ml of pyridine was heated to reflux for 4 h. The solvent was then removed and a viscous brown oil remained. The resulting oil was dissolved in chloroform and the solution was washed with small batches (3 × 10 ml) of water. Pure (I) was obtained as a white powder following removal of the chloroform solvent. Crystals of (I) were produced by diffusion of methanol into the DMSO solution (yield 70%).

Refinement top

The compound crystallizes as well formed plates which all appear to suffer from twinning no matter what solvent is used. A full sphere of data was collected in the normal way. The structure could be solved from the data that was culled from a good orientation matrix; however it was clear that much of the data was being discarded. The initial model yielded a value of R1 = 0.174 with 4156 reflections [Fo > 4σ(Fo)]. Subsequently, the existence of rotationally related twin components (a 180° rotation around 001) was confirmed using the program GEMINI (Bruker, 1999). Integration was performed separately on the two components. Several methods of combining the two sets of reflection data were tried. For example, 6476 observed data, including partially overlapped reflections, yielded a R1 value of 0.103. With partials omitted, a value of R1 = 0.056 was obtained, but this resulted in only 1452 observed data and a rather low data-to-parameter ratio; nevertheless the refinement was quite stable. Finally, the data was sent to Michael Ruf at Bruker AXS, Inc, who integrated it using a beta test version of SAINT (Bruker, 2001), modified to handle multi-component integration. SAINT processes the data simultaneously, determining profile shapes, updating matrices independently. If spots start to overlap SAINT will combine the overlapping integration boxes and do a simple summation. SAINT will not use overlapping reflections for matrix refinement or statistics. The results of this integration are the results being reported because the number of data (8879 unique, 6786 observed) obtained is superior. The twin component is 0.357 (2). Cell parameters are based on the reflections of the major component. Although the completeness is only 82% at the θmax of 30.5°, it is 97% complete at θ of 30.0°.

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1994); software used to prepare material for publication: SHELXL97.

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) showing the atom-labeling scheme. Displacement ellipsoids are shown at the 50% probability level.
[Figure 2] Fig. 2. A view of the hydrogen-bonding scheme.
[Figure 3] Fig. 3. A comparison of the relatively extended structure of (I) with the more folded structure of tris[2-(benzoylamino)ethyl]amine (II) (Goldcamp et al., 2000).
Nitrilotriacetanilide top
Crystal data top
C24H24N4O3Z = 2
Mr = 416.47F(000) = 440
Triclinic, P1Dx = 1.360 Mg m3
a = 8.411 (2) ÅMo Kα radiation, λ = 0.71073 Å
b = 8.819 (2) ÅCell parameters from 999 reflections
c = 14.886 (4) Åθ = 2.5–31.1°
α = 84.684 (6)°µ = 0.09 mm1
β = 82.425 (6)°T = 91 K
γ = 68.439 (6)°Plate, colorless
V = 1016.7 (4) Å30.48 × 0.28 × 0.04 mm
Data collection top
Bruker SMART 1000
diffractometer
6786 reflections with I > 2σ(I)
Radiation source: normal-focus sealed tubeRint = 0.060
Graphite monochromatorθmax = 30.5°, θmin = 2.5°
Detector resolution: 8.3 pixels mm-1h = 1111
ω scansk = 1212
7955,7827 measured reflectionsl = 2021
8879 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.067Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.239H-atom parameters constrained
S = 1.23 w = 1/[σ2(Fo2) + (0.0619P)2 + 3.3081P]
where P = (Fo2 + 2Fc2)/3
8879 reflections(Δ/σ)max = 0.001
281 parametersΔρmax = 0.59 e Å3
0 restraintsΔρmin = 0.47 e Å3
Crystal data top
C24H24N4O3γ = 68.439 (6)°
Mr = 416.47V = 1016.7 (4) Å3
Triclinic, P1Z = 2
a = 8.411 (2) ÅMo Kα radiation
b = 8.819 (2) ŵ = 0.09 mm1
c = 14.886 (4) ÅT = 91 K
α = 84.684 (6)°0.48 × 0.28 × 0.04 mm
β = 82.425 (6)°
Data collection top
Bruker SMART 1000
diffractometer
6786 reflections with I > 2σ(I)
7955,7827 measured reflectionsRint = 0.060
8879 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0670 restraints
wR(F2) = 0.239H-atom parameters constrained
S = 1.23Δρmax = 0.59 e Å3
8879 reflectionsΔρmin = 0.47 e Å3
281 parameters
Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.9631 (3)0.8152 (3)0.36205 (19)0.0216 (6)
O20.4162 (3)0.7777 (3)0.55058 (18)0.0183 (6)
O30.5423 (4)0.6546 (3)0.20056 (19)0.0210 (6)
N10.8131 (4)0.7963 (4)0.2485 (2)0.0166 (7)
H10.71380.79180.23910.020*
N20.1558 (4)0.8082 (4)0.5056 (2)0.0166 (6)
H20.09310.83850.45970.020*
N30.5089 (4)0.4272 (4)0.2757 (2)0.0154 (6)
H30.50550.37990.33030.018*
N40.5471 (4)0.7814 (3)0.3632 (2)0.0149 (6)
C10.6751 (5)0.8216 (5)0.4029 (2)0.0165 (7)
H1A0.71210.74640.45620.020*
H1B0.62240.93400.42440.020*
C20.8330 (5)0.8093 (4)0.3353 (3)0.0162 (7)
C30.9313 (5)0.7890 (4)0.1700 (3)0.0166 (8)
C41.0639 (5)0.8493 (5)0.1653 (3)0.0194 (8)
H41.08310.89310.21710.023*
C51.1674 (5)0.8448 (5)0.0844 (3)0.0229 (9)
H51.25850.88500.08130.027*
C61.1408 (5)0.7826 (5)0.0078 (3)0.0232 (9)
H61.21140.78220.04750.028*
C71.0093 (5)0.7208 (5)0.0132 (3)0.0240 (9)
H70.99110.67560.03830.029*
C80.9049 (5)0.7255 (5)0.0939 (3)0.0208 (8)
H80.81410.68470.09720.025*
C90.3682 (5)0.8678 (4)0.3951 (3)0.0168 (7)
H9A0.29470.85030.35340.020*
H9B0.34660.98610.39300.020*
C100.3155 (5)0.8141 (4)0.4920 (3)0.0158 (7)
C110.0814 (4)0.7566 (4)0.5885 (3)0.0161 (7)
C120.0152 (5)0.6591 (5)0.5836 (3)0.0188 (8)
H120.03290.63260.52630.023*
C130.0855 (5)0.6006 (5)0.6629 (3)0.0247 (9)
H130.15150.53430.65970.030*
C140.0596 (5)0.6388 (5)0.7459 (3)0.0240 (9)
H140.10560.59660.79990.029*
C150.0328 (5)0.7379 (5)0.7512 (3)0.0248 (9)
H150.04850.76510.80880.030*
C160.1030 (5)0.7984 (5)0.6726 (3)0.0192 (8)
H160.16530.86780.67640.023*
C170.5886 (5)0.6060 (4)0.3583 (3)0.0158 (7)
H17A0.52520.56690.41030.019*
H17B0.71310.54770.36220.019*
C180.5407 (5)0.5682 (4)0.2698 (3)0.0158 (7)
C190.4806 (4)0.3471 (4)0.2044 (3)0.0151 (7)
C200.4276 (5)0.4260 (5)0.1226 (3)0.0184 (8)
H200.41360.53770.11120.022*
C210.3950 (5)0.3413 (5)0.0574 (3)0.0191 (8)
H210.36080.39510.00100.023*
C220.4121 (5)0.1786 (5)0.0739 (3)0.0221 (8)
H220.38780.12190.02950.027*
C230.4649 (5)0.0997 (5)0.1558 (3)0.0224 (9)
H230.47800.01180.16720.027*
C240.4984 (5)0.1831 (5)0.2207 (3)0.0197 (8)
H240.53370.12870.27680.024*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0223 (14)0.0245 (14)0.0206 (14)0.0107 (12)0.0066 (11)0.0017 (13)
O20.0201 (14)0.0192 (13)0.0153 (13)0.0073 (11)0.0027 (11)0.0021 (12)
O30.0279 (15)0.0201 (14)0.0173 (14)0.0114 (12)0.0044 (11)0.0023 (12)
N10.0130 (15)0.0197 (15)0.0164 (16)0.0051 (13)0.0027 (12)0.0016 (14)
N20.0160 (15)0.0185 (15)0.0147 (15)0.0052 (13)0.0049 (12)0.0022 (14)
N30.0183 (16)0.0159 (14)0.0127 (15)0.0074 (13)0.0021 (12)0.0013 (13)
N40.0151 (15)0.0112 (13)0.0175 (15)0.0034 (12)0.0020 (12)0.0012 (13)
C10.0206 (19)0.0178 (17)0.0119 (18)0.0077 (15)0.0021 (14)0.0006 (16)
C20.0188 (18)0.0115 (15)0.0190 (19)0.0069 (14)0.0017 (14)0.0012 (15)
C30.0170 (18)0.0138 (17)0.0152 (18)0.0028 (14)0.0006 (14)0.0043 (15)
C40.0174 (18)0.0187 (18)0.021 (2)0.0056 (15)0.0010 (15)0.0000 (17)
C50.0170 (19)0.0224 (19)0.029 (2)0.0075 (16)0.0027 (16)0.0012 (19)
C60.0162 (19)0.027 (2)0.021 (2)0.0037 (16)0.0008 (15)0.0032 (18)
C70.025 (2)0.028 (2)0.019 (2)0.0083 (18)0.0052 (16)0.0007 (18)
C80.0197 (19)0.026 (2)0.021 (2)0.0126 (17)0.0037 (15)0.0013 (17)
C90.0159 (18)0.0174 (17)0.0159 (18)0.0053 (15)0.0019 (14)0.0034 (15)
C100.0191 (18)0.0099 (15)0.0163 (18)0.0035 (14)0.0000 (14)0.0004 (15)
C110.0123 (17)0.0136 (16)0.0192 (19)0.0014 (14)0.0017 (14)0.0011 (16)
C120.0141 (17)0.0175 (17)0.022 (2)0.0022 (14)0.0017 (15)0.0008 (17)
C130.0156 (18)0.0202 (19)0.036 (3)0.0067 (16)0.0007 (17)0.0043 (19)
C140.0166 (19)0.0220 (19)0.026 (2)0.0025 (16)0.0044 (16)0.0049 (19)
C150.025 (2)0.0216 (19)0.023 (2)0.0036 (17)0.0016 (17)0.0012 (18)
C160.0178 (18)0.0165 (17)0.022 (2)0.0052 (15)0.0004 (15)0.0013 (17)
C170.0176 (18)0.0127 (16)0.0168 (19)0.0048 (14)0.0028 (14)0.0012 (15)
C180.0132 (17)0.0165 (17)0.0165 (18)0.0039 (14)0.0005 (13)0.0023 (15)
C190.0122 (17)0.0154 (17)0.0170 (18)0.0036 (14)0.0024 (13)0.0022 (15)
C200.0172 (18)0.0194 (18)0.020 (2)0.0079 (16)0.0022 (14)0.0004 (16)
C210.0188 (18)0.0241 (19)0.0154 (19)0.0086 (16)0.0034 (14)0.0007 (16)
C220.0194 (19)0.0224 (19)0.024 (2)0.0051 (16)0.0039 (16)0.0086 (18)
C230.020 (2)0.0135 (17)0.032 (2)0.0018 (15)0.0090 (17)0.0015 (18)
C240.0194 (19)0.0173 (18)0.021 (2)0.0047 (15)0.0047 (15)0.0008 (16)
Geometric parameters (Å, º) top
O1—C21.233 (4)C9—C101.536 (5)
O2—C101.234 (4)C9—H9A0.9900
O3—C181.225 (4)C9—H9B0.9900
N1—C21.345 (5)C11—C161.389 (5)
N1—C31.421 (5)C11—C121.395 (5)
N1—H10.8800C12—C131.391 (6)
N2—C101.351 (5)C12—H120.9500
N2—C111.422 (5)C13—C141.373 (6)
N2—H20.8800C13—H130.9500
N3—C181.357 (5)C14—C151.380 (6)
N3—C191.419 (5)C14—H140.9500
N3—H30.8800C15—C161.391 (6)
N4—C91.451 (5)C15—H150.9500
N4—C11.457 (4)C16—H160.9500
N4—C171.462 (4)C17—C181.526 (5)
C1—C21.533 (5)C17—H17A0.9900
C1—H1A0.9900C17—H17B0.9900
C1—H1B0.9900C19—C201.387 (5)
C3—C81.385 (5)C19—C241.400 (5)
C3—C41.393 (5)C20—C211.389 (5)
C4—C51.385 (6)C20—H200.9500
C4—H40.9500C21—C221.390 (6)
C5—C61.386 (6)C21—H210.9500
C5—H50.9500C22—C231.388 (6)
C6—C71.393 (6)C22—H220.9500
C6—H60.9500C23—C241.382 (5)
C7—C81.386 (6)C23—H230.9500
C7—H70.9500C24—H240.9500
C8—H80.9500
C2—N1—C3128.5 (3)N2—C10—C9114.8 (3)
C2—N1—H1115.7C16—C11—C12119.7 (4)
C3—N1—H1115.7C16—C11—N2122.6 (3)
C10—N2—C11124.9 (3)C12—C11—N2117.7 (3)
C10—N2—H2117.5C13—C12—C11119.9 (4)
C11—N2—H2117.5C13—C12—H12120.0
C18—N3—C19127.7 (3)C11—C12—H12120.0
C18—N3—H3116.2C14—C13—C12120.0 (4)
C19—N3—H3116.2C14—C13—H13120.0
C9—N4—C1116.9 (3)C12—C13—H13120.0
C9—N4—C17112.8 (3)C13—C14—C15120.4 (4)
C1—N4—C17113.6 (3)C13—C14—H14119.8
N4—C1—C2112.3 (3)C15—C14—H14119.8
N4—C1—H1A109.1C14—C15—C16120.4 (4)
C2—C1—H1A109.1C14—C15—H15119.8
N4—C1—H1B109.1C16—C15—H15119.8
C2—C1—H1B109.1C11—C16—C15119.6 (4)
H1A—C1—H1B107.9C11—C16—H16120.2
O1—C2—N1125.3 (4)C15—C16—H16120.2
O1—C2—C1120.0 (4)N4—C17—C18110.8 (3)
N1—C2—C1114.7 (3)N4—C17—H17A109.5
C8—C3—C4119.7 (4)C18—C17—H17A109.5
C8—C3—N1117.0 (3)N4—C17—H17B109.5
C4—C3—N1123.2 (4)C18—C17—H17B109.5
C5—C4—C3119.2 (4)H17A—C17—H17B108.1
C5—C4—H4120.4O3—C18—N3125.3 (4)
C3—C4—H4120.4O3—C18—C17121.4 (3)
C4—C5—C6121.3 (4)N3—C18—C17113.1 (3)
C4—C5—H5119.3C20—C19—C24119.4 (4)
C6—C5—H5119.3C20—C19—N3123.1 (3)
C5—C6—C7119.1 (4)C24—C19—N3117.4 (3)
C5—C6—H6120.4C19—C20—C21119.9 (4)
C7—C6—H6120.4C19—C20—H20120.1
C8—C7—C6119.8 (4)C21—C20—H20120.1
C8—C7—H7120.1C22—C21—C20120.6 (4)
C6—C7—H7120.1C22—C21—H21119.7
C3—C8—C7120.8 (4)C20—C21—H21119.7
C3—C8—H8119.6C23—C22—C21119.5 (4)
C7—C8—H8119.6C23—C22—H22120.2
N4—C9—C10113.8 (3)C21—C22—H22120.2
N4—C9—H9A108.8C24—C23—C22120.1 (4)
C10—C9—H9A108.8C24—C23—H23120.0
N4—C9—H9B108.8C22—C23—H23120.0
C10—C9—H9B108.8C23—C24—C19120.5 (4)
H9A—C9—H9B107.7C23—C24—H24119.7
O2—C10—N2124.5 (4)C19—C24—H24119.7
O2—C10—C9120.7 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3···O2i0.882.173.012 (4)161
N2—H2···O1ii0.882.002.830 (4)158
N1—H1···O30.882.353.153 (4)153
N1—H1···N40.882.182.665 (5)114
Symmetry codes: (i) x+1, y+1, z+1; (ii) x1, y, z.

Experimental details

Crystal data
Chemical formulaC24H24N4O3
Mr416.47
Crystal system, space groupTriclinic, P1
Temperature (K)91
a, b, c (Å)8.411 (2), 8.819 (2), 14.886 (4)
α, β, γ (°)84.684 (6), 82.425 (6), 68.439 (6)
V3)1016.7 (4)
Z2
Radiation typeMo Kα
µ (mm1)0.09
Crystal size (mm)0.48 × 0.28 × 0.04
Data collection
DiffractometerBruker SMART 1000
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
7955,7827, 8879, 6786
Rint0.060
(sin θ/λ)max1)0.714
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.067, 0.239, 1.23
No. of reflections8879
No. of parameters281
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.59, 0.47

Computer programs: SMART (Bruker, 2000), SAINT (Bruker, 2001), SAINT, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), SHELXTL (Sheldrick, 1994), SHELXL97.

Selected bond lengths (Å) top
O1—C21.233 (4)N2—C111.422 (5)
O2—C101.234 (4)N3—C181.357 (5)
O3—C181.225 (4)N3—C191.419 (5)
N1—C21.345 (5)N4—C91.451 (5)
N1—C31.421 (5)N4—C11.457 (4)
N2—C101.351 (5)N4—C171.462 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3···O2i0.882.173.012 (4)161.4
N2—H2···O1ii0.882.002.830 (4)157.5
N1—H1···O30.882.353.153 (4)152.6
N1—H1···N40.882.182.665 (5)114.0
Symmetry codes: (i) x+1, y+1, z+1; (ii) x1, y, z.
 

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