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Acta Crystallogr Sect E Struct Rep Online. 2008 January 1; 64(Pt 1): m66–m67.
Published online 2007 December 6. doi:  10.1107/S1600536807063337
PMCID: PMC2914947

Bis(isopropyl­ammonium) tetra­sulfido­molybdate(VI)


The title compound, (C3H10N)2[MoS4], was synthesized by passing a rapid stream of H2S into an aqueous isopropyl­amine solution of molybdic acid. The title compound is isotypic with the corresponding W analogue (C3H10N)2[WS4]; its structure consists of a slightly distorted tetra­hedral [MoS4]2− dianion and two crystallographically independent isopropyl­ammonium cations, with all atoms located in general positions. The cations and anion are linked by weak N—H(...)S and C—H(...)S inter­actions, the strength and number of which can explain the observed Mo—S bond distances.

Related literature

Previous reports give details of the structural characterization of several organic ammonium tetra­sulfidomolybdates derived from chiral amines (Srinivasan, Naik et al., 2007 [triangle]), diamines (Srinivasan et al., 2001 [triangle]; Srinivasan, Dhuri et al., 2005 [triangle]; Srinivasan, Näther & Bensch 2005 [triangle]), triamines (Srinivasan, Dhuri et al., 2007 [triangle]), cyclic amines (Srinivasan, Näther & Bensch 2006 [triangle]), a tetra­amine (Srinivasan et al., 2004 [triangle]), a primary amine (Srinivasan, Näther, Naik & Bensch 2006 [triangle]) and a secondary amine (Srinivasan, Girkar & Raghavaiah 2007 [triangle]). The title compound is isotypic with the corresponding W analogue (C3H10N)2[WS4] (Srinivasan, Näther, Dhuri & Bensch 2006 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-00m66-scheme1.jpg


Crystal data

  • (C3H10N)2[MoS4]
  • M r = 344.42
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-00m66-efi7.jpg
  • a = 20.2640 (14) Å
  • b = 13.9118 (12) Å
  • c = 11.0933 (8) Å
  • β = 110.076 (8)°
  • V = 2937.3 (4) Å3
  • Z = 8
  • Mo Kα radiation
  • μ = 1.43 mm−1
  • T = 170 (2) K
  • 0.13 × 0.1 × 0.08 mm

Data collection

  • Stoe IPDS 1 diffractometer
  • Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1998 [triangle]) T min = 0.756, T max = 0.830
  • 10806 measured reflections
  • 3134 independent reflections
  • 2716 reflections with I > 2σ(I)
  • R int = 0.025


  • R[F 2 > 2σ(F 2)] = 0.026
  • wR(F 2) = 0.071
  • S = 1.03
  • 3134 reflections
  • 125 parameters
  • H-atom parameters constrained
  • Δρmax = 0.64 e Å−3
  • Δρmin = −0.72 e Å−3

Data collection: IPDS Program Package (Stoe & Cie, 1998 [triangle]); cell refinement: IPDS Program Package; data reduction: IPDS Program Package; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997 [triangle]); molecular graphics: DIAMOND (Brandenburg, 1999 [triangle]); software used to prepare material for publication: CIFTAB in SHELXTL (Bruker, 1998 [triangle]).

Table 1
Selected geometric parameters (Å, °)
Table 2
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536807063337/si2062sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536807063337/si2062Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report


This work was supported by the Department of Science and Technology (DST), New Delhi, under grant No. SR/S1/IC-41/2003. ARN thanks the Deutscher Akademisher Austauschdienst (DAAD), Bonn, for a short-term visit to the University of Kiel.

supplementary crystallographic information


As part of an ongoing research programme, we are investigating the synthesis and structural aspects of organic ammonium tetrasulfidometalates of the group VI metals Mo and W (Srinivasan, Naik et al., 2007). In earlier work we have structurally characterized several [MoS4]2- compounds linked to organic cations derived from chiral amines (Srinivasan, Naik et al., 2007), diamines (Srinivasan et al., 2001; Srinivasan, Dhuri et al., 2005; Srinivasan, Näther & Bensch 2005), triamines (Srinivasan, Dhuri et al., 2007), cyclic amines (Srinivasan, Näther & Bensch 2006), a tetraamine (Srinivasan et al., 2004), a primary amine (Srinivasan, Näther, Naik & Bensch 2006) and a secondary amine (Srinivasan, Girkar & Raghavaiah 2007). All the organic ammonium tetrasulfidomolybdates exhibit several weak hydrogen bonding interactions between the organic cations and [MoS4]2- anions. We have shown that in some organic [MoS4]2- compounds the organic amines are partially protonated (Srinivasan, Dhuri et al., 2007). In the present work, we have employed isopropylamine (ipNH2) for the synthesis of the title compound, which is isostructural with the corresponding W compound (C3H10N)2[WS4] (Srinivasan, Näther, Dhuri & Bensch 2006).

The structure of the title compound consists of discrete tetrahedral [MoS4]2- ions and two crystallographically independent isopropylammonium cations (ipNH2)+ (Fig. 1), with all atoms located in general positions. The geometric parameters of the organic cations are in agreement with those reported for the analogous [WS4]2- compound. The MoS4 tetrahedron is slightly distorted with S—Mo—S angles between 109.01 (2) and 110.42 (2) ° (Table 1). The Mo—S bond distances range from 2.1695 (6) to 2.2085 (6) Å with an average value of 2.1893 Å and are comparable to the bond lengths observed in several reported tetrathiomolybdates (Srinivasan, Dhuri et al., 2007). Two of the Mo—S bond lengths are shorter than the average Mo—S distance while the other two are longer. The weak H-bonding interactions between the cations and anions can explain the observed short and long Mo—S bond distances. A scrutiny of the structure reveals that the organic cations and tetrathiomolybdate anions are linked with the aid of several N—H···S and C—H···S hydrogen bonding interactions (Table 2). Thus each [MoS4]2- is hydrogen bonded to seven different organic cations with the aid of eight N—H···S bonds and two weak C—H···S interactions (Fig.2). An examination of the surroundings of the cations reveals that one organic cation (N1) is H-bonded to three different [MoS4]2- ions while the second organic cation (N2) is surrounded by four different [MoS4]2- ions (Table 2). One H atom on each N atom functions as a bifurcated donor with the other two functioning as singly shared donors. One H atom attached to a methyl group from each unique cation is involved in a weak C—H···S interaction. S4 atom which makes the longest Mo—S bond at 2.2085 (6) Å is involved in three singly shared N—H···S bonds. S4 also makes the shortest singly shared N—H···S bond at 2.43 Å, which can explain the elongation of this bond. In contrast, S2 atom involved in the shortest Mo—S bond at 2.1695 (6) Å makes a bifurcated N—H···S bond at a longer S···H distance accompanied by a small NH—S angle. As a result of the H-bonding interactions, the cations and anions are organized such that the organic ammonium ions always point towards the S atoms of [MoS4]2- as is evident in the observed sequence ···(ipNH2)+ ··· [MoS4]2-···(ipNH2)+ (ipNH2)+ ··· [MoS4]2- ···(ipNH2)+ and so on when viewed along the c axis (Fig. 3). The observed difference Δ between the longest and the shortest Mo—S bond of 0.0390 Å in the title compound is quite longer than the Δ value of 0.0334 Å in the isostructural tetrathiotungstate compound (C3H10N)2[WS4] (Srinivasan et al., 2007a).


A rapid stream of H2S gas was passed into a solution containing molybdic acid (3 g) dissolved in water (30 ml) and isopropyl amine (10 ml). After 30 min when crystals begin to appear, the gas passing was stopped and the deep red reaction mixture was filtered. The filtrate was left aside for crystallization. After 3 to 4 h the crystalline product was filtered, washed with a little ice-cold water (2 ml), followed by 2-propanol (20 ml) and diethyl ether (10 ml) and dried to obtain 3.2 g of the title compound.


All H atoms were located in difference map but were positioned with idealized geometry ((CH3 and NH3 allowed to rotate but not to tip) with 1.00 Å (C—H), 0.98 Å (methyl) and N—H = 0.91 Å) and were refined using a riding model, with Uiso(H) fixed at 1.5Ueq(CH3 and NH3) and 1.5Ueq(NH3).


Fig. 1.
The molecular structure of the title compound showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level.
Fig. 2.
A view of the surroundings of the [MoS4]2- anion showing its linking to seven different (ipNH2)+ cations with the aid of eight N—H···S and two C—H···S interactions, shown as broken lines. ...
Fig. 3.
A view along c axis of the crystallographic packing of the title compound showing the organization of the organic cations and [MoS4]2- anions. H-bonds are shown as broken lines.

Crystal data

(C3H10N)2[MoS4]F000 = 1408
Mr = 344.42Dx = 1.558 Mg m3
Monoclinic, C2/cMo Kα radiation λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 8000 reflections
a = 20.2640 (14) Åθ = 12.5–28.0º
b = 13.9118 (12) ŵ = 1.43 mm1
c = 11.0933 (8) ÅT = 170 (2) K
β = 110.076 (8)ºNeedle, red
V = 2937.3 (4) Å30.13 × 0.1 × 0.08 mm
Z = 8

Data collection

STOE IPDS 1 diffractometer3134 independent reflections
Radiation source: fine-focus sealed tube2716 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.025
T = 170(2) Kθmax = 27.1º
Phi Scan scansθmin = 2.4º
Absorption correction: numerical(X-SHAPE; Stoe & Cie, 1998)h = −23→25
Tmin = 0.756, Tmax = 0.830k = −17→17
10806 measured reflectionsl = −13→14


Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.026  w = 1/[σ2(Fo2) + (0.0498P)2 + 0.8301P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.071(Δ/σ)max = 0.001
S = 1.03Δρmax = 0.64 e Å3
3134 reflectionsΔρmin = −0.72 e Å3
125 parametersExtinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.00132 (18)
Secondary atom site location: difference Fourier map

Special details

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)

Mo0.277534 (8)0.660872 (11)0.763180 (16)0.01395 (9)
S10.16255 (3)0.66070 (4)0.71330 (6)0.02148 (14)
S20.32646 (3)0.64606 (4)0.96951 (5)0.02172 (14)
S30.31057 (3)0.79621 (4)0.70333 (5)0.02302 (14)
S40.31079 (3)0.53985 (4)0.66851 (6)0.02458 (14)
N10.34948 (9)0.61362 (13)0.41696 (19)0.0219 (4)
C10.42792 (12)0.60477 (18)0.4708 (3)0.0292 (6)
C20.45832 (14)0.61919 (19)0.3658 (3)0.0346 (6)
C30.45457 (18)0.6778 (3)0.5776 (3)0.0557 (10)
N20.17411 (10)0.40310 (14)0.51513 (19)0.0247 (4)
C40.10154 (11)0.44146 (15)0.4922 (2)0.0197 (4)
C50.08879 (15)0.52564 (17)0.4005 (3)0.0323 (6)
C60.04982 (13)0.35982 (18)0.4430 (3)0.0307 (6)

Atomic displacement parameters (Å2)

Mo0.01492 (12)0.01177 (12)0.01591 (12)−0.00135 (6)0.00626 (8)0.00189 (6)
S10.0147 (3)0.0242 (3)0.0243 (3)−0.00166 (18)0.0051 (2)0.0059 (2)
S20.0215 (3)0.0247 (3)0.0167 (3)−0.0033 (2)0.0038 (2)0.00321 (19)
S30.0266 (3)0.0171 (3)0.0275 (3)−0.0053 (2)0.0121 (2)0.0054 (2)
S40.0337 (3)0.0184 (3)0.0257 (3)0.0004 (2)0.0154 (3)−0.0027 (2)
N10.0182 (9)0.0205 (9)0.0258 (10)−0.0003 (7)0.0060 (8)0.0033 (7)
C10.0181 (11)0.0290 (12)0.0371 (14)0.0021 (9)0.0049 (10)0.0151 (10)
C20.0260 (12)0.0357 (14)0.0461 (16)−0.0012 (10)0.0174 (12)−0.0046 (12)
C30.0378 (17)0.103 (3)0.0258 (14)−0.0309 (17)0.0098 (13)−0.0058 (16)
N20.0184 (9)0.0315 (10)0.0242 (10)−0.0023 (8)0.0073 (8)0.0044 (8)
C40.0190 (10)0.0219 (10)0.0211 (10)−0.0015 (8)0.0107 (9)−0.0011 (8)
C50.0462 (15)0.0203 (11)0.0348 (13)0.0051 (10)0.0195 (12)0.0037 (10)
C60.0205 (11)0.0278 (12)0.0444 (15)−0.0041 (9)0.0118 (11)0.0000 (11)

Geometric parameters (Å, °)

Mo—S22.1695 (6)C3—H3B0.9800
Mo—S32.1769 (5)C3—H3C0.9800
Mo—S12.2023 (6)N2—C41.502 (3)
Mo—S42.2085 (6)N2—H1N20.9100
N1—C11.499 (3)N2—H2N20.9100
N1—H2N10.9100C4—C51.514 (3)
N1—H3N10.9100C4—C61.514 (3)
C1—C21.506 (4)C4—H41.0000
C1—C31.513 (4)C5—H5A0.9800
S2—Mo—S3109.08 (2)C1—C3—H3C109.5
S2—Mo—S1109.02 (3)H3A—C3—H3C109.5
S3—Mo—S1109.51 (2)H3B—C3—H3C109.5
S2—Mo—S4109.01 (2)C4—N2—H1N2109.5
S3—Mo—S4109.78 (2)C4—N2—H2N2109.5
S1—Mo—S4110.42 (2)H1N2—N2—H2N2109.5
C1—N1—H3N1109.5N2—C4—C5108.67 (19)
H1N1—N1—H3N1109.5N2—C4—C6108.12 (18)
H2N1—N1—H3N1109.5C5—C4—C6113.6 (2)
N1—C1—C2109.9 (2)N2—C4—H4108.8
N1—C1—C3107.5 (2)C5—C4—H4108.8
C2—C1—C3112.7 (2)C6—C4—H4108.8

Hydrogen-bond geometry (Å, °)

N1—H1N1···S40.912.433.310 (2)162
N1—H2N1···S4i0.912.473.359 (2)165
N1—H3N1···S1ii0.912.543.4297 (19)165
N1—H3N1···S3ii0.912.853.3019 (19)112
N2—H1N2···S3iii0.912.583.376 (2)147
N2—H1N2···S2iii0.912.923.580 (2)131
N2—H2N2···S40.912.433.309 (2)164
N2—H3N2···S1i0.912.503.393 (2)169
C2—H2A···S4i0.982.973.759 (3)139
C5—H5B···S3ii0.982.983.639 (6)126

Symmetry codes: (i) x, −y+1, z−1/2; (ii) −x+1/2, −y+3/2, −z+1; (iii) −x+1/2, y−1/2, −z+3/2.


Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: SI2062).


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