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The compound [MgCl2(C18H15OP)2] was inadvertantly crystallized during a reaction involving magnesium germanide. It is isostructural to the Mn, Co, Cu and Zn analogs. Since four-coordinate Mg is rare, its structure is reported here. The Mg atom lies on a twofold axis and is surrounded by two O atoms and two Cl atoms in a distorted tetrahedral coordination geometry.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803009723/ww6077sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536803009723/ww6077Isup2.hkl
Contains datablock I

CCDC reference: 214788

Key indicators

  • Single-crystal X-ray study
  • T = 90 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.023
  • wR factor = 0.061
  • Data-to-parameter ratio = 24.4

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

General Notes

REFLT_03 From the CIF: _diffrn_reflns_theta_max 30.00 From the CIF: _reflns_number_total 4774 From the CIF: _diffrn_reflns_limit_ max hkl 26. 45. 13. From the CIF: _diffrn_reflns_limit_ min hkl -26. -45. -13. TEST1: Expected hkl limits for theta max Calculated maximum hkl 29. 45. 13. Calculated minimum hkl -29. -45. -13. ALERT: Expected hkl max differ from CIF values REFLT_03 From the CIF: _diffrn_reflns_theta_max 30.00 From the CIF: _reflns_number_total 4774 Count of symmetry unique reflns 2524 Completeness (_total/calc) 189.14% TEST3: Check Friedels for noncentro structure Estimate of Friedel pairs measured 2250 Fraction of Friedel pairs measured 0.891 Are heavy atom types Z>Si present yes Please check that the estimate of the number of Friedel pairs is correct. If it is not, please give the correct count in the _publ_section_exptl_refinement section of the submitted CIF.

Comment top

Dichlorobis(triphenylphosphine oxide)magnesium, (I), was prepared serendipitously from the reaction of germanium tetrachloride, triphenylphosphine and magnesium germanide in 2-methoxyethyl ether. We were interested in trapping intermediates formed during the preparation of germanium nanoclusters (Taylor et al., 1999) with triphenylphosphine and obtained colorless parallelepiped crystals of (I).

Crystals of (I) are orthorhombic and crystallize in space group Fdd2 as do its analogues where magnesium is replaced with zinc (Rose et al., 1980; Kosky et al., 1982), copper (Bertrand & Kalyanaraman, 1971; Weinberger, 1997), cobalt (Cotton et al., 2002), and manganese (Tomita, 1985). The only notable difference is that (I) has a more idealized tetrahedral coordination, with bond angles about the metal atom ranging from 101.44 (5) to 113.54 (3)°. Table 1 compares various geometric parameters of the MII isomorphs. The dihedral angle between the O—M—O' and Cl—M—Cl' planes is another measure of distortion from idealized tetrahedral geometry since an angle of 90° would correspond to tetrahedral and 0° would correspond to square planar. This angle is similar in all of the complexes except in the Cu complex. It shows considerable flattening of the tetrahedral geometry, as has been previously noted (Rose et al., 1980; Kosky, et al., 1982; Weinberger et al., 1997). Compound (I) is soluble in polar organic solvents, such as chloroform and dichloromethane, supporting the use of phosphine oxides as extraction agents for alkaline earth metals (Arnaud-Neu et al., 1999).

Experimental top

2-Methoxyethyl ether was distilled twice under argon from sodium and benzophenone prior to use. A degassed solution of triphenylphosphine (0.345 g, 1.32 mmol) and germanium tetrachloride (0.15 ml, 0.282 g, 1.32 mmol) and 20 ml of 2-methoxyethyl ether was added to a 250 ml Schlenk flask containing magnesium germanide (53 mg, 0.437 mmol) and 2-methoxyethyl ether (20 ml). The resultant mixture was refluxed for 18 h and cooled. Volatiles were removed in vacuo. Solids were dissolved in 10 ml of dried, degassed dichloromethane and separated from a small amount of solids via cannula. Over the period of several months crystals of (I) formed from this solution.

Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SMART; data reduction: SAINT (Bruker, 2002); 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. View of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry code: (i) 1.5 − x, 0.5 − y, z.]
(I) top
Crystal data top
[MgCl2(C18H15OP)2]F(000) = 2704
Mr = 651.75Dx = 1.319 Mg m3
Orthorhombic, Fdd2Mo Kα radiation, λ = 0.71073 Å
Hall symbol: F 2 -2dCell parameters from 718 reflections
a = 20.786 (2) Åθ = 2.3–30.5°
b = 32.459 (3) ŵ = 0.35 mm1
c = 9.7270 (11) ÅT = 90 K
V = 6562.8 (12) Å3Parallelepiped, colorless
Z = 80.43 × 0.23 × 0.13 mm
Data collection top
Bruker SMART 1000
diffractometer
4774 independent reflections
Radiation source: normal-focus sealed tube4691 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.020
Detector resolution: 8.3 pixels mm-1θmax = 30.0°, θmin = 2.3°
ω scansh = 2626
Absorption correction: multi-scan
(SADABS; Sheldrick, 2001)
k = 4545
Tmin = 0.865, Tmax = 0.956l = 1313
21340 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.023H-atom parameters constrained
wR(F2) = 0.061 w = 1/[σ2(Fo2) + (0.0408P)2 + 2.5125P]
where P = (Fo2 + 2Fc2)/3
S = 1.07(Δ/σ)max = 0.002
4774 reflectionsΔρmax = 0.32 e Å3
196 parametersΔρmin = 0.16 e Å3
1 restraintAbsolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.03 (3)
Crystal data top
[MgCl2(C18H15OP)2]V = 6562.8 (12) Å3
Mr = 651.75Z = 8
Orthorhombic, Fdd2Mo Kα radiation
a = 20.786 (2) ŵ = 0.35 mm1
b = 32.459 (3) ÅT = 90 K
c = 9.7270 (11) Å0.43 × 0.23 × 0.13 mm
Data collection top
Bruker SMART 1000
diffractometer
4774 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2001)
4691 reflections with I > 2σ(I)
Tmin = 0.865, Tmax = 0.956Rint = 0.020
21340 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.023H-atom parameters constrained
wR(F2) = 0.061Δρmax = 0.32 e Å3
S = 1.07Δρmin = 0.16 e Å3
4774 reflectionsAbsolute structure: Flack (1983)
196 parametersAbsolute structure parameter: 0.03 (3)
1 restraint
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
Mg10.75000.25000.72539 (5)0.01309 (9)
Cl10.673718 (12)0.216943 (9)0.85434 (3)0.02282 (6)
P10.834324 (12)0.178146 (7)0.54955 (3)0.01390 (6)
O10.78833 (4)0.21078 (2)0.59911 (9)0.01861 (14)
C10.81838 (5)0.16767 (3)0.37141 (11)0.01635 (18)
C20.77734 (6)0.19449 (4)0.30159 (14)0.0258 (2)
H2A0.75710.21640.34980.031*
C30.76586 (8)0.18932 (4)0.16188 (15)0.0343 (3)
H3A0.73770.20750.11470.041*
C40.79591 (8)0.15726 (4)0.09152 (14)0.0322 (3)
H4A0.78910.15410.00450.039*
C50.83568 (7)0.12994 (4)0.16088 (14)0.0287 (3)
H5A0.85520.10770.11270.034*
C60.84712 (6)0.13498 (3)0.30090 (13)0.0227 (2)
H6A0.87440.11630.34830.027*
C70.91698 (5)0.19363 (3)0.56348 (11)0.01531 (18)
C80.95315 (5)0.20411 (3)0.44715 (11)0.0193 (2)
H8A0.93440.20250.35820.023*
C91.01682 (5)0.21694 (4)0.46239 (12)0.0224 (2)
H9A1.04140.22410.38360.027*
C101.04435 (5)0.21921 (3)0.59173 (13)0.0211 (2)
H10A1.08790.22770.60130.025*
C111.00853 (5)0.20912 (3)0.70795 (12)0.0204 (2)
H11A1.02750.21090.79660.024*
C120.94482 (5)0.19648 (3)0.69417 (11)0.0189 (2)
H12A0.92030.18980.77350.023*
C130.82614 (5)0.13194 (3)0.64971 (11)0.01660 (18)
C140.76701 (5)0.12396 (3)0.71411 (12)0.0195 (2)
H14A0.73190.14230.70210.023*
C150.76015 (6)0.08900 (4)0.79572 (12)0.0237 (2)
H15A0.72010.08340.83870.028*
C160.81172 (6)0.06216 (4)0.81468 (12)0.0245 (2)
H16A0.80700.03870.87220.029*
C170.87014 (6)0.06971 (4)0.74944 (14)0.0255 (2)
H17A0.90500.05110.76120.031*
C180.87760 (5)0.10449 (3)0.66693 (12)0.0218 (2)
H18A0.91750.10960.62240.026*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mg10.0119 (2)0.0158 (2)0.0116 (2)0.00002 (16)0.0000.000
Cl10.01663 (10)0.03282 (13)0.01900 (12)0.00568 (9)0.00349 (9)0.00370 (10)
P10.01418 (10)0.01428 (10)0.01322 (11)0.00117 (8)0.00047 (9)0.00044 (9)
O10.0182 (3)0.0186 (3)0.0190 (3)0.0031 (3)0.0025 (3)0.0026 (3)
C10.0185 (4)0.0160 (4)0.0146 (5)0.0002 (3)0.0010 (4)0.0007 (3)
C20.0332 (6)0.0221 (5)0.0221 (5)0.0074 (4)0.0068 (5)0.0011 (4)
C30.0484 (8)0.0292 (6)0.0252 (6)0.0042 (6)0.0137 (6)0.0021 (5)
C40.0512 (8)0.0293 (6)0.0162 (5)0.0069 (5)0.0058 (5)0.0015 (4)
C50.0409 (7)0.0239 (5)0.0214 (6)0.0009 (5)0.0014 (5)0.0074 (4)
C60.0289 (5)0.0190 (4)0.0203 (5)0.0046 (4)0.0007 (4)0.0028 (4)
C70.0160 (4)0.0149 (4)0.0150 (4)0.0003 (3)0.0007 (3)0.0001 (3)
C80.0177 (5)0.0247 (5)0.0155 (5)0.0004 (4)0.0012 (4)0.0002 (4)
C90.0175 (5)0.0302 (5)0.0194 (5)0.0004 (4)0.0041 (4)0.0021 (4)
C100.0148 (4)0.0251 (5)0.0235 (5)0.0011 (4)0.0002 (4)0.0015 (4)
C110.0196 (5)0.0231 (5)0.0185 (5)0.0000 (4)0.0032 (4)0.0011 (4)
C120.0198 (5)0.0223 (5)0.0147 (5)0.0015 (4)0.0009 (4)0.0012 (4)
C130.0186 (5)0.0167 (4)0.0145 (4)0.0013 (3)0.0013 (3)0.0005 (3)
C140.0222 (5)0.0191 (4)0.0172 (5)0.0017 (4)0.0030 (4)0.0020 (4)
C150.0307 (6)0.0220 (5)0.0183 (5)0.0065 (4)0.0060 (4)0.0013 (4)
C160.0363 (6)0.0205 (5)0.0166 (5)0.0071 (4)0.0043 (4)0.0037 (4)
C170.0269 (6)0.0223 (5)0.0273 (6)0.0018 (4)0.0088 (5)0.0066 (4)
C180.0185 (5)0.0214 (5)0.0255 (5)0.0000 (4)0.0039 (4)0.0050 (4)
Geometric parameters (Å, º) top
Mg1—O11.9401 (8)C8—C91.3953 (16)
Mg1—O1i1.9401 (8)C8—H8A0.9500
Mg1—Cl1i2.2889 (4)C9—C101.3841 (17)
Mg1—Cl12.2889 (4)C9—H9A0.9500
P1—O11.5062 (8)C10—C111.3926 (16)
P1—C71.7952 (10)C10—H10A0.9500
P1—C131.7966 (11)C11—C121.3929 (15)
P1—C11.7966 (11)C11—H11A0.9500
C1—C21.3954 (15)C12—H12A0.9500
C1—C61.3976 (15)C13—C181.4021 (15)
C2—C31.3899 (19)C13—C141.4036 (15)
C2—H2A0.9500C14—C151.3922 (16)
C3—C41.393 (2)C14—H14A0.9500
C3—H3A0.9500C15—C161.3933 (18)
C4—C51.388 (2)C15—H15A0.9500
C4—H4A0.9500C16—C171.3920 (18)
C5—C61.3922 (17)C16—H16A0.9500
C5—H5A0.9500C17—C181.3936 (15)
C6—H6A0.9500C17—H17A0.9500
C7—C121.3999 (15)C18—H18A0.9500
C7—C81.4005 (15)
O1—Mg1—O1i101.44 (5)C9—C8—C7119.73 (10)
O1—Mg1—Cl1i111.72 (3)C9—C8—H8A120.1
O1i—Mg1—Cl1i108.90 (3)C7—C8—H8A120.1
O1—Mg1—Cl1108.90 (3)C10—C9—C8120.30 (10)
O1i—Mg1—Cl1111.72 (3)C10—C9—H9A119.8
Cl1i—Mg1—Cl1113.54 (3)C8—C9—H9A119.8
O1—P1—C7112.73 (5)C9—C10—C11120.29 (10)
O1—P1—C13110.70 (5)C9—C10—H10A119.9
C7—P1—C13106.46 (5)C11—C10—H10A119.9
O1—P1—C1108.95 (5)C10—C11—C12119.96 (11)
C7—P1—C1107.60 (5)C10—C11—H11A120.0
C13—P1—C1110.34 (5)C12—C11—H11A120.0
P1—O1—Mg1157.64 (6)C11—C12—C7119.99 (10)
C2—C1—C6119.75 (11)C11—C12—H12A120.0
C2—C1—P1117.65 (8)C7—C12—H12A120.0
C6—C1—P1122.56 (8)C18—C13—C14119.83 (10)
C3—C2—C1120.36 (12)C18—C13—P1121.54 (8)
C3—C2—H2A119.8C14—C13—P1118.62 (8)
C1—C2—H2A119.8C15—C14—C13119.64 (10)
C2—C3—C4119.57 (12)C15—C14—H14A120.2
C2—C3—H3A120.2C13—C14—H14A120.2
C4—C3—H3A120.2C14—C15—C16120.41 (11)
C5—C4—C3120.37 (12)C14—C15—H15A119.8
C5—C4—H4A119.8C16—C15—H15A119.8
C3—C4—H4A119.8C17—C16—C15120.06 (10)
C4—C5—C6120.16 (12)C17—C16—H16A120.0
C4—C5—H5A119.9C15—C16—H16A120.0
C6—C5—H5A119.9C16—C17—C18120.13 (11)
C5—C6—C1119.76 (11)C16—C17—H17A119.9
C5—C6—H6A120.1C18—C17—H17A119.9
C1—C6—H6A120.1C17—C18—C13119.92 (11)
C12—C7—C8119.72 (9)C17—C18—H18A120.0
C12—C7—P1118.86 (8)C13—C18—H18A120.0
C8—C7—P1121.39 (8)
Symmetry code: (i) x+3/2, y+1/2, z.

Experimental details

Crystal data
Chemical formula[MgCl2(C18H15OP)2]
Mr651.75
Crystal system, space groupOrthorhombic, Fdd2
Temperature (K)90
a, b, c (Å)20.786 (2), 32.459 (3), 9.7270 (11)
V3)6562.8 (12)
Z8
Radiation typeMo Kα
µ (mm1)0.35
Crystal size (mm)0.43 × 0.23 × 0.13
Data collection
DiffractometerBruker SMART 1000
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2001)
Tmin, Tmax0.865, 0.956
No. of measured, independent and
observed [I > 2σ(I)] reflections
21340, 4774, 4691
Rint0.020
(sin θ/λ)max1)0.703
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.023, 0.061, 1.07
No. of reflections4774
No. of parameters196
No. of restraints1
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.32, 0.16
Absolute structureFlack (1983)
Absolute structure parameter0.03 (3)

Computer programs: SMART (Bruker, 2002), SMART, SAINT (Bruker, 2002), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), SHELXTL (Sheldrick, 1994), SHELXL97.

Comparison of geometric parameters (Å, °) for MCl2(OPPh3)2 (M = Mg, Mn, Cu, Co, Zn) top
MIIM-OM-ClM-O-PDihedralRange of angles at MII
Mga1.9401 (8)2.2889 (4)157.64 (6)88.0101.4–113.5
Mnb2.069 (6)2.294 (3)156.0 (4)87.598.6–115.7
Coc1.971 (2)2.2269 (10)153.5 (2)87.897.9–112.8
Cud2.011 (3)2.132 (2)148.5 (2)71.489.7–127.8
Zne1.974 (5)2.204 (2)153.4 (3)87.796.8–116.3
Znf1.967 (5)2.187 (3)154.1 (3)87.897.0–117.2
References: (a) this work; (b) Tomita et al. (1985); (c) Cotton et al. (2002); (d) Weinberger et al. (1997); (e) Rose et al. (1980); (f) Kosky et al. (1982).
 

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