Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270108039772/ln3118sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270108039772/ln3118Isup2.hkl |
CCDC reference: 718099
The title compound was prepared as described previously (Hegetschweiler et al., 1993). Colorless crystals for the X-ray diffraction study were taken directly from the mother liquor. In addition, a dried sample (monohydrate) of composition [Bi3(H-3taci)2]Cl3.H2O was prepared for elemental analysis (performed by Dr Thomas Kull, Solvias AG, Basel, Switzerland). Found: Bi 56.9, C 13.16, Cl 9.67, H 2.44, N 7.75%; Bi3C12Cl3H26N6O7 requires: Bi 57.0, C 13.11, Cl 9.67, H 2.38, N 7.64%. The 1H and 13C NMR characteristics of this sample correspond to those presented in the former report (Hegetschweiler et al., 1993).
As already reported previously (Hegetschweiler et al., 1993), the title compound crystallizes in a trigonal lattice; in the present study the space group R32 was chosen according to the considerations of Marsh (2002). A total of six low-angle reflections (3.43 < θ < 8.61°) with Fo2 significantly smaller than Fc2 were excluded from the data set. Based on elemental analysis, the total occupancy for the two Cl positions is only 1.5. This could be realized either by a 75% occupancy for both positions or individually by 50% for one of them and 100% for the other. Inspection of the relevant electron density clearly established that the position of atom Cl1 is fully occupied, whereas the electron density of atom Cl2 is somewhat reduced. We therefore assigned a fixed site occupation factor of 1.0 to atom Cl1 and 0.5 to atom Cl2. However, it appeared that the 50% occupancy of Cl2 did not account for the entire amount of electron density observed. We therefore added a further O atom (O300) at this position, also with a site occupation factor of 0.5. The two atoms, Cl2 and O300, were refined with identical positional and displacement parameters. Obviously, a chloride counter-ion and a water molecule occupy this position at random with equal probability. The H atoms of the corresponding water molecule (O300) could not be observed and were not considered in the refinement. The H atoms of the remaining water molecules (O100 and O200) were located in difference Fourier maps. They were refined isotropically with O—H bond distances restrained to 0.85 (1) Å and Uiso values fixed at 1.5Ueq of the parent O atom. Since O100 is located on a crystallographic threefold axis, its H atom (H100) received a site occupation factor of 0.67. The positions of the C– and N-bonded H atoms were calculated and refined using a riding model with C—H distances of 1.00 Å and N—H = 0.92 Å, and with Uiso fixed at 1.2 Ueq of the parent atom. The largest electron density peak (1.69 e Å-3) was located 0.25 Å from the disordered Cl2/O300 system.
Data collection: SAINT (Bruker, 2006); cell refinement: SAINT (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Diamond (Brandenburg, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
[Bi3(C6H12N3O3)2]Cl3·6H2O | Dx = 2.936 Mg m−3 |
Mr = 1189.76 | Mo Kα radiation, λ = 0.71073 Å |
Trigonal, R32 | Cell parameters from 57564 reflections |
a = 8.0903 (11) Å | θ = 2.9–36.3° |
c = 35.612 (7) Å | µ = 19.93 mm−1 |
V = 2018.6 (6) Å3 | T = 100 K |
Z = 3 | Transparent parallelepiped, colorless |
F(000) = 1638 | 0.26 × 0.18 × 0.10 mm |
Bruker–Nonius KappaCCD diffractometer | 1983 independent reflections |
Radiation source: rotating anode | 1981 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.043 |
3292 images at 0.5 deg. stepwise rotation in ω and phi, 20 sec./frame scans | θmax = 35.0°, θmin = 3.0° |
Absorption correction: gaussian (XPREP; Bruker, 2003) | h = −13→13 |
Tmin = 0.048, Tmax = 0.186 | k = −13→13 |
24418 measured reflections | l = −57→57 |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H atoms treated by a mixture of independent and constrained refinement |
R[F2 > 2σ(F2)] = 0.021 | w = 1/[σ2(Fo2) + (0.0234P)2 + 11.670P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.049 | (Δ/σ)max = 0.001 |
S = 1.15 | Δρmax = 1.69 e Å−3 |
1983 reflections | Δρmin = −2.19 e Å−3 |
63 parameters | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
2 restraints | Extinction coefficient: 0.00122 (8) |
Primary atom site location: structure-invariant direct methods | Absolute structure: Flack (1983), 824 Friedel pairs |
Secondary atom site location: difference Fourier map | Absolute structure parameter: −0.009 (8) |
[Bi3(C6H12N3O3)2]Cl3·6H2O | Z = 3 |
Mr = 1189.76 | Mo Kα radiation |
Trigonal, R32 | µ = 19.93 mm−1 |
a = 8.0903 (11) Å | T = 100 K |
c = 35.612 (7) Å | 0.26 × 0.18 × 0.10 mm |
V = 2018.6 (6) Å3 |
Bruker–Nonius KappaCCD diffractometer | 1983 independent reflections |
Absorption correction: gaussian (XPREP; Bruker, 2003) | 1981 reflections with I > 2σ(I) |
Tmin = 0.048, Tmax = 0.186 | Rint = 0.043 |
24418 measured reflections |
R[F2 > 2σ(F2)] = 0.021 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.049 | w = 1/[σ2(Fo2) + (0.0234P)2 + 11.670P] where P = (Fo2 + 2Fc2)/3 |
S = 1.15 | Δρmax = 1.69 e Å−3 |
1983 reflections | Δρmin = −2.19 e Å−3 |
63 parameters | Absolute structure: Flack (1983), 824 Friedel pairs |
2 restraints | Absolute structure parameter: −0.009 (8) |
Experimental. crystal faces, dist/mm 1.00 -1.00 0.00 0.090 -1.00 1.00 0.00 0.090 1.00 0.00 0.00 0.170 -1.00 0.00 0.00 0.110 0.00 0.00 1.00 0.050 0.00 0.00 -1.00 0.050 0.00 -1.00 0.00 0.130 0.00 1.00 0.00 0.130 |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Bi1 | 0.730187 (17) | 1.0000 | 1.0000 | 0.01675 (6) | |
Cl1 | 0.3333 | 0.6667 | 1.00044 (5) | 0.0255 (3) | |
N11 | 0.6525 (4) | 0.9995 (4) | 0.92809 (8) | 0.0163 (4) | |
H11A | 0.5405 | 0.8920 | 0.9214 | 0.020* | |
H11B | 0.6473 | 1.1066 | 0.9214 | 0.020* | |
C11 | 0.8207 (4) | 1.0000 (4) | 0.91213 (8) | 0.0145 (4) | |
H11 | 0.8137 | 1.0000 | 0.8841 | 0.017* | |
C12 | 0.8186 (4) | 0.8187 (4) | 0.92535 (8) | 0.0149 (4) | |
H12 | 0.7066 | 0.7067 | 0.9135 | 0.018* | |
O12 | 0.7969 (3) | 0.7968 (3) | 0.96504 (6) | 0.0164 (4) | |
O100 | 0.6667 | 1.3333 | 0.87920 (19) | 0.0346 (11) | |
H100 | 0.755 (11) | 1.310 (16) | 0.873 (3) | 0.052* | 0.67 |
O200 | 0.6667 | 0.6252 (8) | 0.8333 | 0.0431 (13) | |
H200 | 0.742 (11) | 0.730 (7) | 0.822 (3) | 0.065* | |
Cl2 | 0.3333 | 0.6667 | 0.86439 (5) | 0.0149 (3) | 0.50 |
O300 | 0.3333 | 0.6667 | 0.86439 (5) | 0.0149 (3) | 0.50 |
U11 | U22 | U33 | U12 | U13 | U23 | |
Bi1 | 0.01478 (6) | 0.02167 (8) | 0.01610 (7) | 0.01083 (4) | 0.00012 (2) | 0.00025 (5) |
Cl1 | 0.0173 (3) | 0.0173 (3) | 0.0419 (8) | 0.00864 (17) | 0.000 | 0.000 |
N11 | 0.0138 (10) | 0.0176 (10) | 0.0189 (10) | 0.0088 (8) | −0.0011 (7) | −0.0009 (7) |
C11 | 0.0158 (10) | 0.0162 (10) | 0.0124 (9) | 0.0086 (8) | −0.0010 (8) | −0.0009 (8) |
C12 | 0.0147 (10) | 0.0152 (10) | 0.0144 (10) | 0.0071 (8) | 0.0003 (8) | −0.0003 (8) |
O12 | 0.0205 (9) | 0.0199 (9) | 0.0133 (8) | 0.0135 (9) | 0.0037 (7) | 0.0035 (7) |
O100 | 0.0330 (17) | 0.0330 (17) | 0.038 (3) | 0.0165 (8) | 0.000 | 0.000 |
O200 | 0.052 (4) | 0.048 (2) | 0.030 (3) | 0.0262 (18) | −0.015 (2) | −0.0075 (10) |
Cl2 | 0.0164 (4) | 0.0164 (4) | 0.0119 (6) | 0.0082 (2) | 0.000 | 0.000 |
O300 | 0.0164 (4) | 0.0164 (4) | 0.0119 (6) | 0.0082 (2) | 0.000 | 0.000 |
Bi1—O12i | 2.329 (2) | C11—C12 | 1.533 (4) |
Bi1—O12 | 2.331 (2) | C11—H11 | 1.0000 |
Bi1—N11 | 2.636 (3) | C12—O12 | 1.424 (4) |
Bi1—Cl1 | 2.9871 (4) | C12—H12 | 1.0000 |
N11—C11 | 1.473 (4) | O100—H100 | 0.852 (10) |
N11—H11A | 0.9200 | O200—H200 | 0.850 (11) |
N11—H11B | 0.9200 | ||
O12ii—Bi1—O12i | 108.52 (12) | N11iii—Bi1—Cl1 | 81.24 (7) |
O12ii—Bi1—O12iii | 75.30 (12) | Cl1iv—Bi1—Cl1 | 102.864 (4) |
O12i—Bi1—O12iii | 64.61 (9) | Bi1v—Cl1—Bi1 | 119.997 (1) |
O12ii—Bi1—O12 | 64.61 (9) | Bi1v—Cl1—Bi1vi | 119.997 (1) |
O12i—Bi1—O12 | 75.30 (12) | Bi1—Cl1—Bi1vi | 119.997 (1) |
O12iii—Bi1—O12 | 108.48 (12) | C11—N11—Bi1 | 98.95 (16) |
O12ii—Bi1—N11 | 131.09 (8) | C11—N11—H11A | 112.0 |
O12i—Bi1—N11 | 67.69 (8) | Bi1—N11—H11A | 112.0 |
O12iii—Bi1—N11 | 131.20 (8) | C11—N11—H11B | 112.0 |
O12—Bi1—N11 | 67.62 (8) | Bi1—N11—H11B | 112.0 |
O12ii—Bi1—N11iii | 67.69 (8) | H11A—N11—H11B | 109.7 |
O12i—Bi1—N11iii | 131.09 (8) | N11—C11—C12 | 108.1 (2) |
O12iii—Bi1—N11iii | 67.62 (8) | N11—C11—C12i | 108.4 (2) |
O12—Bi1—N11iii | 131.20 (8) | C12—C11—C12i | 111.9 (3) |
N11—Bi1—N11iii | 152.50 (11) | N11—C11—H11 | 109.5 |
O12ii—Bi1—Cl1iv | 147.62 (6) | C12—C11—H11 | 109.5 |
O12i—Bi1—Cl1iv | 83.33 (6) | C12i—C11—H11 | 109.5 |
O12iii—Bi1—Cl1iv | 83.66 (6) | O12—C12—C11 | 111.4 (2) |
O12—Bi1—Cl1iv | 147.04 (6) | O12—C12—C11vii | 111.3 (2) |
N11—Bi1—Cl1iv | 81.24 (6) | C11—C12—C11vii | 110.1 (3) |
N11iii—Bi1—Cl1iv | 81.71 (6) | O12—C12—H12 | 108.0 |
O12ii—Bi1—Cl1 | 83.33 (7) | C11—C12—H12 | 108.0 |
O12i—Bi1—Cl1 | 147.62 (6) | C11vii—C12—H12 | 108.0 |
O12iii—Bi1—Cl1 | 147.04 (6) | C12—O12—Bi1vii | 120.13 (17) |
O12—Bi1—Cl1 | 83.66 (7) | C12—O12—Bi1 | 120.01 (17) |
N11—Bi1—Cl1 | 81.71 (7) | Bi1vii—O12—Bi1 | 108.46 (9) |
O12ii—Bi1—Cl1—Bi1v | 148.00 (8) | N11—C11—C12—O12 | −51.3 (3) |
O12i—Bi1—Cl1—Bi1v | −97.62 (12) | C12i—C11—C12—O12 | 68.0 (3) |
O12iii—Bi1—Cl1—Bi1v | 98.56 (12) | N11—C11—C12—C11vii | −175.3 (2) |
O12—Bi1—Cl1—Bi1v | −146.92 (8) | C12i—C11—C12—C11vii | −56.0 (4) |
N11—Bi1—Cl1—Bi1v | −78.70 (8) | C11—C12—O12—Bi1vii | −131.3 (2) |
N11iii—Bi1—Cl1—Bi1v | 79.64 (8) | C11vii—C12—O12—Bi1vii | −7.9 (3) |
Cl1iv—Bi1—Cl1—Bi1v | 0.28 (3) | C11—C12—O12—Bi1 | 8.0 (3) |
O12ii—Bi1—Cl1—Bi1vi | −33.04 (8) | C11vii—C12—O12—Bi1 | 131.3 (2) |
O12i—Bi1—Cl1—Bi1vi | 81.34 (13) | O12ii—Bi1—O12—C12 | −172.15 (19) |
O12iii—Bi1—Cl1—Bi1vi | −82.48 (13) | O12i—Bi1—O12—C12 | −52.9 (2) |
O12—Bi1—Cl1—Bi1vi | 32.04 (8) | O12iii—Bi1—O12—C12 | −109.2 (2) |
N11—Bi1—Cl1—Bi1vi | 100.26 (8) | N11—Bi1—O12—C12 | 18.6 (2) |
N11iii—Bi1—Cl1—Bi1vi | −101.41 (8) | N11iii—Bi1—O12—C12 | 174.74 (19) |
Cl1iv—Bi1—Cl1—Bi1vi | 179.24 (9) | Cl1iv—Bi1—O12—C12 | −1.7 (3) |
O12ii—Bi1—N11—C11 | −54.4 (2) | Cl1—Bi1—O12—C12 | 102.3 (2) |
O12i—Bi1—N11—C11 | 41.20 (16) | O12ii—Bi1—O12—Bi1vii | −28.66 (12) |
O12iii—Bi1—N11—C11 | 54.0 (2) | O12i—Bi1—O12—Bi1vii | 90.56 (9) |
O12—Bi1—N11—C11 | −41.46 (16) | O12iii—Bi1—O12—Bi1vii | 34.28 (6) |
N11iii—Bi1—N11—C11 | 179.82 (17) | N11—Bi1—O12—Bi1vii | 162.12 (12) |
Cl1iv—Bi1—N11—C11 | 127.54 (17) | N11iii—Bi1—O12—Bi1vii | −41.77 (15) |
Cl1—Bi1—N11—C11 | −127.98 (17) | Cl1iv—Bi1—O12—Bi1vii | 141.83 (5) |
Bi1—N11—C11—C12 | 60.9 (2) | Cl1—Bi1—O12—Bi1vii | −114.26 (9) |
Bi1—N11—C11—C12i | −60.6 (2) |
Symmetry codes: (i) −x+y+1, −x+2, z; (ii) y, x, −z+2; (iii) x−y+1, −y+2, −z+2; (iv) y, x+1, −z+2; (v) −y+1, x−y+1, z; (vi) −x+y, −x+1, z; (vii) −y+2, x−y+1, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
N11—H11A···Cl2 | 0.92 | 2.68 | 3.480 (3) | 146 |
N11—H11B···O100 | 0.92 | 2.31 | 3.167 (5) | 154 |
O100—H100···O200i | 0.85 (1) | 2.11 (5) | 2.871 (6) | 149 (10) |
O200—H200···Cl2viii | 0.85 (1) | 2.26 (3) | 3.084 (3) | 165 (9) |
Symmetry codes: (i) −x+y+1, −x+2, z; (viii) y+1/3, x+2/3, −z+5/3. |
Experimental details
Crystal data | |
Chemical formula | [Bi3(C6H12N3O3)2]Cl3·6H2O |
Mr | 1189.76 |
Crystal system, space group | Trigonal, R32 |
Temperature (K) | 100 |
a, c (Å) | 8.0903 (11), 35.612 (7) |
V (Å3) | 2018.6 (6) |
Z | 3 |
Radiation type | Mo Kα |
µ (mm−1) | 19.93 |
Crystal size (mm) | 0.26 × 0.18 × 0.10 |
Data collection | |
Diffractometer | Bruker–Nonius KappaCCD diffractometer |
Absorption correction | Gaussian (XPREP; Bruker, 2003) |
Tmin, Tmax | 0.048, 0.186 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 24418, 1983, 1981 |
Rint | 0.043 |
(sin θ/λ)max (Å−1) | 0.807 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.021, 0.049, 1.15 |
No. of reflections | 1983 |
No. of parameters | 63 |
No. of restraints | 2 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
w = 1/[σ2(Fo2) + (0.0234P)2 + 11.670P] where P = (Fo2 + 2Fc2)/3 | |
Δρmax, Δρmin (e Å−3) | 1.69, −2.19 |
Absolute structure | Flack (1983), 824 Friedel pairs |
Absolute structure parameter | −0.009 (8) |
Computer programs: SAINT (Bruker, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), Diamond (Brandenburg, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
N11—H11A···Cl2 | 0.92 | 2.68 | 3.480 (3) | 146 |
N11—H11B···O100 | 0.92 | 2.31 | 3.167 (5) | 154 |
O100—H100···O200i | 0.852 (10) | 2.11 (5) | 2.871 (6) | 149 (10) |
O200—H200···Cl2ii | 0.850 (11) | 2.26 (3) | 3.084 (3) | 165 (9) |
Symmetry codes: (i) −x+y+1, −x+2, z; (ii) y+1/3, x+2/3, −z+5/3. |
Hegetschweiler et al. (1993) | this work | |
R3, 304 K | R32, 100 K | |
Bi-O | 2.28 (2) - 2.40 (1) | 2.329 (2), 2.331 (2) |
Bi-N | 2.43 (2), 2.71 (1) | 2.636 (3) |
Bi-Cl | 3.000 (3), 3.002 (3) | 2.9871 (4) |
C-C | 1.50 (3) - 1.55 (2) | 1.533 (4) |
C-N | 1.52 (3), 1.53 (3) | 1.473 (4) |
C-O | 1.40 (2), 1.43 (2) | 1.424 (4) |
The reaction of three equivalents of BiIII with two equivalents of 1,3,5-triamino-1,3,5-trideoxy-cis-inositol (taci) and six equivalents of a base resulted in the spontaneous formation of the trinuclear [Bi3(H-3taci)2]3+ unit. The synthesis, spectroscopic characterization and crystal structure of a hydrated trichloride salt of this cation were reported several years ago (Hegetschweiler et al., 1993). [Bi3(H-3taci)2]Cl3.6H2O, (I), crystallizes in a trigonal lattice, and in the 1993 study the structure was solved and refined in the space group R3. The trinuclear unit was located on a polar C3 axis, with significant displacement of the three Bi centers from a mean position between the two H-3taci3- residues. As a consequence, different Bi—O and, in particular, significantly different Bi—N bond distances were observed. These findings were, however, in contradiction to the 1H and 13C NMR characteristics, which clearly indicated a structure with a symmetric (D3h) binding of the two ligand entities in solution. As usual in such situations, we explained the unexpected asymmetry in terms of a packing effect. It was, however, noted by Marsh (2002) that, in this structure, every atom except the Bi centers either lies on or is paired across an additional C2 axis which, if included, results in the space group R32. Marsh suggested that the significant displacement of the Bi atoms may be due to an inverted assignment of the anomalous scattering, resulting in a polar dispersion error. Inspection of the data set established indeed that an absolute structure had not been assigned at that time. We therefore collected diffraction data from a new crystal of the compound and evaluated the data set successfully by using the space group R32, as suggested by Marsh.
A view of the D3-symmetric, sandwich-type [Bi3(H-3taci)2]3+ unit together with two of the six Cl- anions is shown in Fig. 1. The three Bi atoms form an equilateral triangle, which is encapsulated by two triply deprotonated H-3taci3- ligands. Both ligand entities bind the Bi centers via an O,N,O-axial–equatorial–axial coordination mode with the alkoxo O atoms all serving as µ2 bridges. As a consequence, the Bi centers are bonded to two N atoms and to four alkoxo O atoms (Table 1). A similar trinuclear structure has also been observed for other large metal cations, such as the trivalent lanthanides (Hegetschweiler, 1999).
The hydrated trichloride salt [Bi3(H-3taci)2]Cl3.6H2O is a two-dimensional polymer with the [Bi3(H-3taci)2]3+ units interlinked by µ3-Cl bridges. These bridging interactions result in the formation of layers, oriented perpendicular to the crystallographic c axis (Fig. 2), with an almost planar arrangement of the Bi3 triangles and the bridging Cl1- anions. The symmetry of such an idealized plane can be described by the hexagonal plane group p31m (No. 15). On the basis of a stacking sequence ABCABC··· of such layers, the entire structure can be regarded as a distorted cubic close packing of [Bi3(H-3taci)2]3+ cations, with the bridging Cl1- anions located in trigonal holes and water molecules (O100) in octahedral holes. Atom Cl2 and an additional water molecule (O300) are randomly distributed in the tetrahedral holes with site occupancies of 50% each. A 50% occupancy for Cl2 is in agreement with charge balance considerations and was also confirmed by careful, comprehensive elemental analysis, establishing unambiguously a Bi:taci:Cl molar ratio of 3:2:3. A further water molecule (O200) is located on a twofold axis in between two trinuclear cations. The Cl2 counter-ions and the water molecules, together with the amine groups of the complex cation, form a three-dimensional network of hydrogen bonds (Fig. 3 and Table 2). The Cl1 bridges and the alkoxo groups of the taci residues are not involved in hydrogen bonding.
Although the crystallographic symmetry for the [Bi3(H-3taci)2]3+ cation is D3, it approaches D3h symmetry quite closely. The additional vertical mirror planes which are required for the point group symmetry of D3h correspond to the mirror lines of the above-mentioned plane group p31m. This type of symmetry is, however, broken by the particular ABCABC··· stacking, and, as a consequence, the entire structure is chiral. The evaluation reported here thus fully confirms the considerations of Marsh.