Synthesis, spectroscopic characterization, and structural studies of organogermanium tri- and monothiocarbonates. Crystal structures of Me2Ge[S2CSEt]2, Ph3Ge[SCO2Me], Ph3Ge[SCO2(i-Pr)], and Ph2Ge[SCO2Me]2

319

Synthesis, spectroscopic characterization, and

structural studies of organogermanium tri- and

monothiocarbonates. Crystal structures of

Me₂Ge[S₂CSEt]₂, Ph₃Ge[SCO₂Me],

Ph₃Ge[SCO₂(i-Pr)], and Ph₂Ge[SCO₂Me]₂

John E. Drake and Jincai Yang

Abstract: Two series of S-alkyl trithiocarbonate derivatives of dimethylgermane, Me₂Ge[S₂CSR]₂, and halodiphenylgermane,

Ph₂GeX[S₂CSR], where R = Me, i-Pr, n-Pr, n-Bu and X = Cl, Br, and three series of O-alkyl monothiocarbonate derivatives of

triphenylgermane, Ph₃Ge[SCO₂R], diphenylgermane, Ph₂Ge[SCO₂R], and trimethylgermane, Me₃Ge[SCO₂R], where R = Me,

i-Pr, and n-Pr, have been prepared in 73–92% yields by the reaction of the potassium or sodium salt of the appropriate tri- or

monothiocarbonic acid with dichlorodimethyl-, chlorotriphenyl-, dichlorodiphenyl-, and chlorotrimethylgermane. The

compounds were principally characterized by infrared, Raman, and ¹H and ¹³C NMR spectroscopy, including some variable

temperature studies, as well as by mass spectrometry. Me₂Ge[S₂CSEt]₂, 1: P2₁/m (No. 11) with cell parameters a = 6.647(4)

−

Å, b = 7.423(2) Å, c = 16.290(4) Å, β = 91.07(3)°, V = 803.6(4) Å³, Z = 2, R = 0.0484, R_w= 0.0485. Ph₃Ge[SCO₂Me], 13: P1

(No. 2) with cell parameters a = 9.970(4) Å, b = 10.660(3) Å, c = 9.853(2) Å, α = 101.78(2)°, β = 109.98(2)°, γ = 89.76(3)°, V

−

= 961.0(5) Å³, Z = 2, R = 0.0534, R_w= 0.0451. Ph₃Ge[SCO₂(i-Pr)], 14: P1 (No. 2) with cell parameters a = 14.386(7) Å, b =

18.598(6) Å, c = 9.223(3) Å, α = 102.85(3)°, β = 94.58(3)°, γ = 108.13(3)°, V = 2256(1) Å³, Z = 2, R = 0.0545, R_w= 0.0552.

Ph₂Ge[SCO₂Me]₂, 16: Cc, (No. 9) with cell parameters a = 11.790(4) Å, b = 13.696(5) Å, c = 23.232(6) Å, β = 92.26(3)°, V =

3748(2) Å³, Z = 8, R = 0.0563, R_w= 0.0512. The immediate environment about Ge is that of tetrahedral but the orientations of

the thiocarbonate groups display interesting features.

Key words: structure, germanium, phenyl, methyl, thiocarbonates.

Résumé : On a préparé deux séries de dérivés trithiocarbonates de S-alkyle du diméthylgermane, Me₂Ge[S₂CSR]₂, et

d’halogénodiphénylgermane, Ph₂GeX[S₂CSR], dans lesquels R = Me, i-Pr, Pr, Bu et X = Cl, Br et trois séries de dérivés

monothiocarbonates de O-alkyle du triphénylgermane, Ph₃Ge[SCO₂R], du diphénylgermane, Ph₂Ge[SCO₂R], et du

triméthylgermane, Me₃Ge[SCO₂R], dans lesquels R = Me, i-Pr et Pr, avec des rendements allant de 73 à 92% en procédant à

la réaction du sel de sodium ou de potassium de l’acide tri- ou monothiocarbonique approprié avec le dichlorodiméthyl-,

chlorotriphényl-, dichlorodiphényl- et le chlorotriméthylgermane. On a généralement caractérisé les composés par le biais des

spectroscopies infrarouge, Raman et RMN du ¹H et du ¹³C, y compris des études à températures variables, ainsi que par

spectrométrie de masse. Me₂Ge[S₂CSEt]₂, 1 : P2₁/m (No. 11), avec a = 6,647(4), b = 7,423(2) et c = 16,290(4) D, β =

−

91,07(3)°, V = 803,6(4) D³, Z = 2, R = 0,0484, R_w= 0,0485. Ph₃Ge[SCO₂Me], 13 : P1 (No. 2), avec a = 9,970(4), b =

10,660(3) et c = 9,853(2) D, α = 101,78(2)°, β = 109,98(2)° et γ = 89,76(3)°, V = 961,0(5) D³, Z = 2, R = 0,0534, R_w= 0,0451.

−

Ph₃Ge[SCO₂(i-Pr)], 14 :P1 (No. 2), avec a = 14,386(7), b = 18,598(6) et c = 9,223(3) D, α = 102,85(3)°, β = 94,58(3)° et γ =

108,13(3)°, V = 2256(1) D³, Z = 2, R = 0,0545, R_w= 0,0552. Ph₂Ge[SCO₂Me]₂, 16 : Cc (No. 9), avec a = 11,790(4), b =

13,696(5) et c = 23,232(6) D, β = 92,26(3)°, V = 3748(2) D³, Z = 8, R = 0,0563, R_w= 0,0512. L’environnement immédiat du

Ge est tétraédrique, mais les orientations des groupes thiocarbonates présentent des caractéristiques intéressantes.

Mots clés : structure, germanium, phényle, méthyle, thiocarbonates.

[Traduit par la rédaction]

Introduction

A wide variety of studies on O-alkyl dithiocarbonates (xan-

thates) have been reported but the analogous trithio- and

Received October 3, 1997.

monothiocarbonates have received considerably less attention.

For trithiocarbonates, this can be attributed to the relative ease

with which they undergo carbon disulfide elimination (1–3)

and most reports relate to transition metal derivatives. As part

of our studies on organogermanium dithio carbonates, car-

bamates, and phosphates (4–14), we have reported on a few

J.E. Drake¹and J. Yang.²Department of Chemistry and

Biochemistry, University of Windsor, Windsor, ON N9B 3P4,

Canada.

1

Author to whom correspondence may be addressed.

Telephone: (519) 253-4232, ext 3551. Fax: (519) 973-7098.

Can. J. Chem. 76: 319–334 (1998)

320

Can. J. Chem. Vol. 76, 1998

trithiocarbonate derivatives (15), and herein is reported an ex-

tension of this work involving S-alkyl trithiocarbonate deriva-

produce Me₂Ge[S₂CSEt]₂, 1, a yellow solid (0.30 g, 0.80

mmol, yield 92%). Recrystallization from CS₂at –15°C gave

yellow crystals, mp 35°C. Prepared similarly were

Me₂Ge[S₂CS(i-Pr)]₂, 2, Me₂Ge[S₂CS(n-Pr)]₂, 3, and

Me₂Ge[S₂CS(n-Bu)]₂, 4, all as yellow oils in yields of 82, 85,

and 80%, respectively.

tives

of

dimethylgermane,

Me₂Ge[S₂CSR]₂,

and

halodiphenylgermane, Ph₂GeX[S₂CSR], where R = Me, i-Pr,

n-Pr, n-Bu and X = Cl, Br. Monothiocarbonate derivatives

have received even less attention and again virtually all reports

have involved transition metal complexes (16–20). With the

exception of those on alkali metal salts (21), only one report on

main group element monothiocarbonates, describing some or-

ganotellurium derivatives, has appeared (22). Three series of

O-alkyl monothiocarbonate derivatives of triphenylgermane,

Ph₃Ge[SCO₂R], diphenylgermane, Ph₂Ge[SCO₂R]₂, and

trimethylgermane, Me₃Ge[SCO₂R], where R = Me, i-Pr, and

n-Pr are discussed. All of the compounds described were char-

acterized by NMR, infrared, and Raman spectroscopy, as well as

by X-ray crystallography when suitable crystals were obtained.

Synthesis of (S-organo trithiocarbonato)chloro-

dimethylgermanes

Ph₂GeCl[S₂CSEt], 5, Ph₂GeCl[S₂CS(i-Pr)], 6,

Ph₂GeCl[S₂CS(n-Pr)], 7, Ph₂GeCl[S₂CS(n-Bu)], 8

Typically, Ph₂GeCl₂(0.30 g, 1.02 mmol), which was con-

tained in a small vial, and dried KS₂CSEt (0.18 g, 1.02 mmol)

were placed in a flask, which was then cooled to –196°C,

degassed, and dried CS₂(ca. 8 mL) was distilled in. The mix-

ture was stirred for ca. 2 h at 0°C, KS₂CSEt and KCl filtered

off, and the solvent allowed to evaporate under vacuum to

produce Ph₂GeCl[S₂CSEt], 5, a yellow oil (0.32 g, 0.81 mmol,

yield 80%). Prepared similarly were Ph₂GeCl[S₂CS(i-Pr)], 6,

Ph₂GeCl[S₂CS(n-Pr)], 7, and Ph₂GeCl[S₂CS(n-Bu)], 8, all as

yellow oils with yields of 80, 78, and 84%, respectively.

Experimental

Materials

Me₃GeCl, Me₂GeCl₂, Ph₃GeCl, Ph₂GeCl₂, and Me₃SiBr were

obtained from Aldrich and Strem Chemicals, all starting mate-

rials being used as supplied. All solvents were dried and dis-

tilled prior to use and all reactions were carried out under

anhydrous conditions. The salts KS₂CSR, where R = Et, i-Pr,

n-Pr, n-Bu, were prepared as described earlier (15) and were

further purified by a method based on that described for dithio-

carbonates (23). The salts NaSCO₂R, where R = Me, i-Pr, n-Pr,

were prepared as follows. Typically, sodium metal (ca. 1.0 g)

was added to dry i-PrOH (ca. 10 mL) in a flask under N₂gas

and the reaction allowed to proceed for 1 h, before COS gas

was bubbled in for 10 min. This was followed by distillation

under vacuum and pumping to dryness to give NaSCO₂(i-Pr);

5.5 g, yield 89%. IR (cm^–1), main features: 1550 br s, 1384 mw,

1371 m, 1186 s, 1086 br s, 973 m, 688 m; Raman (cm^–1): 830

(100); ¹H NMR (ppm relative to DSS): 4.83 (OCH, septet, 6.34

Hz), 1.21 (OCCH₃, d, 6.34 Hz); ¹³C NMR (ppm relative to

DSS): 71.12 (OC), 21.98 (OCC), 185.86 (SCO₂). Similarly

were prepared NaSCO₂Me; yield 85%. IR (cm^–1), main fea-

tures: 1592 vs, vbr, 1428 m, 1188 m, 1120 vs, br, 1040 m, 965

mw, 695 mw; Raman (cm^–1): 825 (100): ¹H NMR (ppm rela-

tive to DSS): 3.68 (CH₃), ¹³C NMR (ppm relative to DSS):

54.36 (CH₃), 186.89 (SCO₂), and NaSCO₂(n-Pr); yield 92%.

IR (cm^–1) main features: 1614 vs, br, 1432 s, 1136 s, 1098 s,

1000 m, 827 m, 668 ms; Raman (cm^–1): 841 (100); ¹H NMR

(ppm relative to DSS): 4.01 (OCH₂, triplet, 6.6 Hz), 1.65

(OCCH₂, m), 0.94 (CH₃, triplet, 7.4 Hz); ¹³C NMR (ppm rela-

tive to DSS): 69.34 (OC), 22.63(OCC), 10.66 (OCCC), 186.64

(SCO₂).

Synthesis of (S-organo trithiocarbonato)bromo-

dimethylgermanes

Ph₂GeBr[S₂CSEt], 9, Ph₂GeBr[S₂CS(i-Pr)], 10,

Ph₂GeBr[S₂CS(n-Pr)], 11, and Ph₂GeBr[S₂CS(n-Bu)], 12

Typically, Ph₂GeCl[S₂CSEt] was prepared in situ as above

from Ph₂GeCl₂(0.31 g, 1.05 mmol) and dried KS₂CSEt (0.18

g, 1.05 mmol). The flask was recooled to –196°C, degassed

again, Me₃SiBr (ca. 0.3 mL) was distilled in, and then the

mixture was stirred for 2 h at 0°C, followed by evaporation

under vacuum to remove Me₃SiCl and any unreacted Me₃SiBr,

to produce Ph₂GeBr[S₂CSEt], 9, as a yellow oil (0.39 g, 0.88

mmol, yield 84%). Similarly were prepared Ph₂GeBr[S₂CS(i-

Pr)], 10, Ph₂GeBr[S₂CS(n-Pr)], 11, and Ph₂GeBr[S₂CS(n-

Bu)], 12, all as yellow oils in yields of 83, 80, and 88%,

respectively. Crystallization of 2–12 using a variety of solvents

and solvent mixtures was not successful, and attempts at ob-

taining boiling points resulted in the immediate release of CS₂.

Attempted preparations of halodimethylgermanium

trithiocarbonates

Efforts to synthesize the species Me₂GeClL and Me₂GeBrL,

where L = S₂CSR; R = Et, i-Pr, n-Pr, n-Bu, were not successful.

The appropriate stoichiometric reactions were shown by NMR

spectroscopy to always give mixtures of Me₂GeXL and

Me₂GeL₂. Because of the lack of stability of these compounds,

isolation by column chromatography did not give the desired

compounds but only decomposition products consistent with

CS₂elimination.

Synthesis of (S-organo trithiocarbonato)

dimethylgermanes

Synthesis of (O-organo monothiocarbonato)-

Me₂Ge[S₂CSEt]₂, 1, Me₂Ge[S₂CS(i-Pr)]₂, 2,

triphenylgermanes

Me₂Ge[S₂CS(n-Pr)]₂, 3, and Me₂Ge[S₂CS(n-Bu)]₂, 4

Typically, Me₂GeCl₂(0.10 mL, 0.87 mmol) and dried CS₂(ca.

10 mL) were distilled onto previously degassed KS₂CSEt (0.35

g, 1.99 mmol) in a flask held at –196°C. The contents were

stirred for ca. 4 h at 0°C. Unreacted KS₂CSEt and KCl were

filtered off and solvent allowed to evaporate under vacuum to

Ph₃Ge[SCO₂Me], 13, Ph₃Ge[SCO₂(i-Pr)], 14, and

Ph₃Ge[SCO₂(n-Pr)], 15

Typically, Ph₃GeCl (0.25 g, 0.74 mmol) and excess, dried

NaSCO₂Me (0.09 g, 0.79 mmol) were placed in a previously

evacuated flask and CH₂Cl₂(ca. 15 mL) was distilled in at

321

Drake and Yang

–196°C. The mixture was stirred for 4 h at room temperature,

followed by filtration and evaporation under vacuum to give

Ph₃Ge[SCO₂Me], 13, a colorless solid (0.26 g, 0.66 mmol,

yield 89%). Recrystallization from a CH₂Cl₂–n-hexane mix-

ture gave colorless crystals, mp 101–102°C. Peaks corre-

sponding to ⁷⁴Ge in a typical germanium cluster were seen at

m/z (relative intensity): 396 ((M)⁺, 2%), 337 ((M – CO₂Me)⁺,

3%), 319 ((M – Ph)⁺, 10%), 305 ((M – SCO₂Me)⁺, 100%), 259

((M – PhCO₂Me)⁺, 30%), 228 ((M – PhSCO₂Me)⁺, 30%), 183

((M – Ph₂CO₂Me)⁺, 5%), and 151 ((M – Ph₂SCO₂Me)⁺, 50%).

Prepared similarly was Ph₃Ge[SCO₂(i-Pr)], 14, a colorless

solid (0.30 g, 0.71 mmol, yield 86%). Recrystallization from a

CH₂Cl₂–n-hexane mixture gave colorless crystals, mp

98–99°C. Similarly was prepared Ph₃Ge[SCO₂(n-Pr)], 15, a

colorless solid (0.29 g, 0.69 mmol, yield 89%), mp

91–93°C. Peaks corresponding to ⁷⁴Ge were seen at m/z (rela-

tive intensity): 305 ((M – SCO₂C₃H₇)⁺, 100%), 287 ((M –

PhSCO)⁺, 15%), 245 ((M – PhSCOC₃H₆)⁺, 20%), 228 ((M –

PhSCO₂C₃H₇)⁺, 38%), and 151 ((M – Ph₂SCO₂C₃H₇)⁺, 46%).

However, attempts at recrystallization failed to give crystals

suitable for X-ray diffraction.

–196°C. The mixture was stirred for 4 h at room temperature,

followed by filtration and evaporation under vacuum to give

Me₃Ge[SCO₂Me], 19, as a colorless liquid (0.25 g, 1.20 mmol,

yield 74%), bp 82–84°C. Similarly were formed

Me₃Ge[SCO₂(i-Pr)], 20, a colorless liquid, yield 76%, bp

92–94°C, and Me₃Ge[SCO₂(n-Pr)], 21, a colorless liquid,

yield 73%, bp 88–90°C.

Attempted preparation of halodiphenylgermanium

monothiocarbonates

Attempts to isolate samples of Ph₂GeCl[SCO₂R] species were

not successful. Reactions with 1:1 molar ratios of Ph₂GeCl₂

and NaSCO₂R always gave mixtures of the halo and bis com-

pounds, as was confirmed from the ¹H NMR spectra.

Physical measurements

The infrared spectra were recorded on a Nicolet 5DX FT spec-

trometer as KBr pellets or oils smeared between KBr windows

in the region 4000–400 cm^–1, and far infrared spectra on a

Bomem DA3 infrared spectrometer between polyethylene

films as oils or Nujol mulls. The Raman spectra were recorded

on samples in sealed glass capillaries on a JEOL-XY Raman

spectrometer using the 5145 Å exciting line of an argon ion

Synthesis of bis(O-organo

1

laser. The H and ¹³C {H}NMR spectra were recorded on a

monothiocarbonato)-diphenylgermanes

Bruker 300 FT/NMR spectrometer at 300.133 and 75.471

MHz, respectively, in CDCl₃using Me₄Si as internal standard.

All NMR spectra were run at ambient temperature, with the

exception of the routine VT NMR studies, and under standard

operating conditions. The melting points were determined on

a Fisher–Johns apparatus. The mass spectra were recorded on

a Kratos Profile GC–MS spectrometer.

Ph₂Ge[SCO₂Me]₂, 16, Ph₂Ge[SCO₂(i-Pr)]₂, 17, and

Ph₂Ge[SCO₂(n-Pr)]₂, 18

Typically, Ph₂GeCl₂(0.25 g, 0.85 mmol) in a vial and

NaSCO₂Me (0.25 g, 2.19 mmol) were placed in a flask and

CH₂Cl₂(ca. 15 mL) was distilled in at –196°C. Reaction and

separation were carried out as for 13 to give Ph₂Ge[SCO₂Me]₂,

16, as a colorless solid (0.30 g, 0.70 mmol, yield 82%). Recrys-

tallization from a CH₂Cl₂–n-hexane mixture gave colorless

crystals, mp 69°C. Peaks corresponding to ⁷⁴Ge were seen at

m/z (relative intensity): 351 ((M – CO₂Me)⁺, 1%), 319 ((M –

SCO₂Me)⁺, 8%), 259 ((M – SCO₂Me(CO₂Me))⁺, 80%), 229 ((M

– SCO₂Me(SCO₂CH₂))⁺, 60%), 151 ((M – Ph(SCO₂Me)₂)⁺,

55%), and 105 (M – Ph₂SCO₂Me(CO₂Me))⁺, 37%), as well as

60 ((COS)⁺, 100%). Similarly was prepared Ph₂Ge[SCO₂(i-

Pr)]₂, 17, as a colorless solid (yield 81%). Peaks corresponding

to ⁷⁴Ge were seen at m/z (relative intensity): 469 ((M)⁺5%),

347 (M – SCO₂C₃H₇)⁺, 32%), 287 (M – SCO₂C₃H₇(COS))⁺,

82%), 229 (M – SCO₂C₃H₇(SCO₂C₃H₆))⁺, 100%), and 183 (M

X-ray crystallographic analysis

Crystals of Me₂Ge[S₂CSEt]₂, 1, were grown from carbon di-

sulfide at –15°C and those of Ph₃Ge[SCO₂Me], 13,

Ph₃Ge[SCO₂(i-Pr)], 14, and Ph₂Ge[SCO₂Me]₂, 16, from

CH₂Cl₂–n-hexane mixtures at 5°C. A yellow block crystal of

1 and colorless block crystals of 13, 14, and 16, of approximate

dimensions 0.38 × 0.24 × 0.18, 0.30 × 0.30 × 0.21, 0.34 × 0.25

× 0.20, and 0.35 × 0.26 × 0.23 mm, respectively, were sealed

in thin-walled glass capillaries and mounted on a Rigaku

AFC6S diffractometer, with graphite-monochromated Mo

Kα radiation.

+

– PhSCO₂C₃H₇(CO₂C₃H₇) , 3%). Recrystallization from a

Data collection was carried out as reported in detail earlier

(10) and the important parameters are included in Table 1. Of

the 1672 (1), 3597 (13), 7522 (14), and 3645 (16) reflections

that were collected, 1536 (1), 3386 (13), 7178 (14), and 3645

(16) were unique. The intensities of three representative reflec-

tions measured after every 150 reflections remained constant

throughout data collection, indicating crystal and electronic

stability (no decay correction was applied for 1, 13, and 16).

However, over the course of data collection the standards de-

creased by 8.2% for 14, so a linear correction factor was ap-

plied. The linear absorption coefficient for Mo Kα is 26.6 for

1, 16.8 for 13, 15.8 for 14, and 18.7 cm^–1for 16. An empirical

absorption correction, based on azimuthal scans of several re-

flections, was applied that resulted in transmission factors

ranging from 0.59 to 1.00 for 1, 0.81 to 1.00 for 13, 0.78 to

1.00 for 14, and 0.77 to 1.00 for 16. The data were corrected

for Lorentz and polarization effects.

CH₂Cl₂–n-hexane mixture gave colorless crystals, mp 95–96°C,

but they were not of X-ray quality. Similarly was formed

Ph₂Ge[SCO₂(n-Pr)]₂, 18, as a colorless oil (yield 81%). Peaks

corresponding to ⁷⁴Ge were seen at m/z (relative intensity): 347

((M–SCO₂C₃H₇)⁺,22%),304((M–SCO₂C₃H₇(C₃H₇))⁺,6%),287((M

– SCO₂C₃H₇)(COS)]⁺, 48%), 259 ((M – SCO₂C₃H₇(CO₂C₃H₇))⁺,

10%), 229 ((M – SCO₂C₃H₇(SCO₂C₃H₆))⁺, 54%), 183 ((M –

PhSCO₂C₃H₇(CO₂C₃H₇)⁺, 23%), and 151 ((M – Ph(SCO₂C₃H₇)₂)⁺,

28%), along with 60 ((COS)+, 67%).

Synthesis of (O-organo

monothiocarbonato)-trimethylgermanes

Me₃Ge[SCO₂Me], 19, Me₃Ge[SCO₂(i-Pr)], 20, and

Me₃Ge[SCO₂(n-Pr)], 21

Typically, Me₃GeCl (0.20 mL, 1.62 mmol) and CH₂Cl₂(ca. 8

mL) were distilled onto NaSCO₂Me (0.22 g, 1.93 mmol) at

The structure was solved by direct methods (24) and all

322

Can. J. Chem. Vol. 76, 1998

Table 1. Summary of crystal data, intensity collection, and structural refinement for Me₂Ge[S₂CSEt]₂, 1,

Ph₃Ge[SCO₂Me], 13, Ph₃Ge[SCO₂(i-Pr)], 14, and Ph₂Ge[SCO₂Me]₂, 16.

Parameter

1

13

14

16

Cell constants

a (Å)

b (Å)

6.647(4)

7.423(2)

16.290(4)

90.00

91.07(3)

90.00

803.6(4)

monoclinic

P2₁/m

377.16

2

9.970(4)

10.660(3)

9.853(2)

101.78(2)

109.98(2)

89.76(3)

961.0(5)

14.386(7)

18.598(6)

9.223(3)

102.85(3)

94.58(3)

108.13(3)

2256(1)

11.790(4)

13.696(5)

23.232(6)

90.00

92.26(3)

90.00

3748(2)

monoclinic

Cc

c (Å)

α (deg)

β (deg)

γ (deg)

Cell volume (Å³)

Crystal system

Space group

Mol.wt (g mol^–1)

Z

triclinic

−

P1

395.01

2

23

1.37

16.8

477.00

2

23

1.369

15.82

0.78–1.00

409.01

8

23

1.45

18.70

Temperature (^oC)

–30

1.56

26.55

0.59–1.00

ρ

_calcd(g cm^–3)

Absorption coefficient µ (cm^–1)

Transmission factors

Radiation

0.81–1.00

0.84–1.07

MoKα 0.71609 Å

Monochromater

Highly oriented graphite

Max 2θ angle

50

Total reflections measured

Unique data used

No. of parameters refined (NP)

R = Σ||F_o| − |F_c|| ⁄ Σ|F_o|

R_w= [(Σw(|F_o| − |F_c|)²⁄ ΣwF_o)]

Goodness of fit

Largest shift/esd, final cycle

Largest resid elect density (e Å^–3)

1672

771

88

0.0484

0.0485

1.88

0.001

0.76

3597

1440

127

0.0534

0.0451

1.63

7522

1725

214

0.0545

0.0552

1.50

3645

1944

225

0.0563

0.0512

2.06

2

0.001

0.43

0.001

0.57

0.001

0.63

calculations were performed using the TEXSAN (25) crystal-

lographic software package of Molecular Structure Corp. The

non-hydrogen atoms were refined anisotropically and the hy-

drogen atoms were included in their idealized position with

C—H set at 0.95 D and with isotropic thermal parameters set

at 1.2 times that of the carbon atom to which they were at-

tached. The final cycle of full-matrix least-squares refinement³

was based on 771 (1), 1440 (13), 1725 (14), and 1944 (16)

observed reflections (I 3.00σ(I)) and 88 (1), 127 (13), 214

(14), and 225 (16) variable parameters and converged (largest

parameter shift was 0.001 times its esd) with unweighted and

weighted agreement factors of R = Σ | |F_o| − |F_c| | ⁄ |F_c| =

0.0485 (1), 0.0534 (13), 0.0545 (14), and 0.0563 (16) and R_w

Table 2. Final fractional coordinates and B(eq) for non-hydrogen

atoms of Me₂Ge[S₂CSEt]₂, 1, with standard deviations in

parentheses.

Atom

x

y

z

B(eq)

Ge(1)

S(1)

S(2)

S(3)

S(4)

S(5)

S(6)

C(1)

C(2)

C(3)

C(4)

C(5)

C(6)

C(7)

0.0127(2)

–0.3109(5)

–0.0433(6)

–0.4925(5)

–0.1083(5)

0.3389(6)

0.0951(6)

–0.266(2)

–0.421(2)

–0.607(3)

0.124(2)

1/4

0.7452(1)

0.7920(2)

0.9427(3)

0.9481(2)

0.6123(2)

0.6158(3)

0.4599(3)

0.8998(8)

1.0565(8)

1.104(1)

3.56(7)

4.1(2)

5.4(2)

3.7(2)

4.2(2)

7.8(3)

5.4(2)

3.2(6)

4.1(8)

6(1)

2

= [(Σw(|F_o| − |F_c|)²/ F_o)]^1/2= 0.0485 (1), 0.0451 (13), 0.0552

(14), and 0.0512 (16). The standard deviation of an observation

4

0.566(1)

0.427(1)

0.340(1)

0.7705(6)

5.0(9)

8(1)

9(1)

of unit weight was 1.88 (1), 1.63 (13), 1.50 (14), and 2.06

0.354(3)

0.366(3)

0.131(1)

(16). The refinement of 16 was carried out on both enantio-

morphs by inverting the structure and the better solution cho-

sen. The maximum and minimum peaks on the final difference

Fourier map corresponded to 0.86 and –0.62 e/D³, respec-

0.018(2)

5.2(6)

3

Least-squares function minimized: Σw( F_o− F_c)², where w

tively, for 1; 0.43 and –0.38 e/D³, respectively, for 13; 0.57

and –0.40 e/D³, respectively, for 14; and 0.63 and –0.53 e/D³,

respectively, for 16.

The final atomic coordinates and equivalent isotropic ther-

mal parameters for the non-hydrogen atoms are given in Ta-

bles 2–5, important distances and bond angles in Tables 6–9,

and ORTEP diagrams in Figs. 1–4. Tables of final anisotropic

= 4F_o(F_o), σ²(F_o) = [S²(C + R²B) + pF_o) ] ⁄ (Lp)², S = scan

rate, C = total integrated peak count, R = ratio of scan time to

background counting time, Lp = Lorentz-polarization factor, and

p = p factor.

2

2 2

4

Standard deviation of an observation of unit weight:

2

[Σw |F | − |F | ⁄ N_o− N_v)^1/2], where N_o= number of

(

)

c

o

observations and N_v= number of variables.

323

Drake and Yang

Table 3. Final fractional coordinates and B(eq) for

non-hydrogen atoms of Ph₃Ge[SCO₂Me], 13, with standard

deviations in parentheses.

Table 4. Final fractional coordinates and B(eq) for

non-hydrogen atoms of Ph₃Ge[SCO₂(i-Pr)], 14, with

standard deviations in parentheses.

Atom

x

y

z

B(eq)

Atom

x

y

z

B(eq)

Ge(1)

S(1)

O(1)

O(2)

C(1)

C(2)

C(3)

C(4)

C(5)

C(6)

C(7)

C(8)

C(9)

C(10)

C(11)

C(12)

C(13)

C(14)

C(15)

C(16)

C(17)

C(18)

C(19)

C(20)

0.8021(1)

0.6413(3)

0.6728(8)

0.5102(7)

0.612(1)

0.469(1)

0.730(1)

0.588(1)

0.541(1)

0.634(1)

0.773(1)

0.825(1)

0.991(1)

1.009(1)

1.151(1)

1.261(1)

1.248(1)

1.107(1)

0.809(1)

0.773(1)

0.781(1)

0.822(1)

0.856(1)

0.851(1)

0.1505(1)

0.2207(2)

0.4161(6)

0.4219(6)

0.370(1)

0.544(1)

0.1554(8)

0.1192(9)

0.114(1)

0.147(1)

0.186(1)

0.191(1)

0.2392(9)

0.370(1)

0.430(1)

0.360(1)

0.234(1)

0.172(1)

–0.0272(9)

–0.127(1)

–0.254(1)

–0.277(1)

–0.182(1)

–0.054(1)

0.1526(1)

0.2601(3)

0.1430(8)

0.2543(7)

0.208(1)

0.217(1)

–0.055(1)

–0.143(1)

–0.294(1)

–0.357(1)

–0.272(1)

–0.119(1)

0.257(1)

0.317(1)

0.387(1)

0.393(1)

0.344(1)

0.270(1)

0.176(1)

0.052(1)

0.071(1)

0.208(1)

0.331(1)

0.317(1)

3.68(4)

4.9(1)

5.4(3)

5.2(3)

4.1(5)

7.2(6)

3.7(2)

4.6(2)

5.4(2)

5.2(2)

5.7(3)

4.9(2)

3.9(2)

7.8(3)

8.3(4)

7.0(3)

6.9(3)

5.6(3)

4.0(2)

5.1(2)

6.2(3)

6.6(3)

6.5(3)

5.3(2)

Ge(1)

Ge(2)

Cl(1)

Cl(2)

S(1)

S(2)

O(1)

O(2)

O(3)

O(4)

C(1)

C(2)

C(3)

C(4)

C(5)

C(6)

C(7)

0.9640(2)

0.4446(1)

0.6910(6)

0.6209(7)

1.1066(4)

0.5905(4)

1.159(1)

1.258(1)

0.643(1)

0.761(1)

1.183(1)

1.321(2)

1.281(2)

1.424(2)

0.9335(9)

0.9620(8)

0.9354(9)

0.8803(9)

0.8518(8)

0.8784(9)

0.966(1)

1.0299(8)

1.0312(8)

0.969(1)

0.9051(8)

0.9037(8)

0.8750(9)

0.794(1)

0.7295(7)

0.7464(8)

0.828(1)

0.8919(7)

0.667(1)

0.835(1)

0.869(2)

0.919(2)

0.4120(8)

0.4304(8)

0.4014(8)

0.3542(9)

0.3358(8)

0.3647(8)

0.3569(9)

0.272(1)

0.2061(7)

0.2252(8)

0.310(1)

0.3761(7)

0.444(1)

0.4973(8)

0.4895(8)

0.428(1)

0.3752(8)

0.3831(8)

0.634(2)

0.8101(1)

0.3182(1)

0.1257(5)

0.0436(5)

0.8712(3)

0.3769(3)

0.7761(9)

0.8311(8)

0.2956(8)

0.3719(7)

0.821(1)

0.4295(2)

–0.0880(2)

0.9721(9)

0.665(1)

0.5929(6)

0.0696(6)

0.381(1)

0.605(2)

–0.167(1)

0.032(1)

0.508(2)

0.560(2)

0.605(3)

0.640(3)

0.395(2)

0.510(1)

0.488(1)

0.352(2)

0.237(1)

0.259(1)

0.243(1)

0.145(1)

0.012(1)

–0.022(1)

0.077(1)

0.210(1)

0.548(1)

0.584(1)

0.669(1)

0.719(1)

0.683(1)

0.598(1)

–0.048(2)

–0.049(2)

–0.147(3)

0.068(2)

–0.125(2)

–0.012(1)

–0.043(1)

–0.187(1)

–0.300(1)

–0.269(1)

0.034(1)

0.061(1)

0.142(1)

0.196(1)

0.169(1)

0.088(1)

–0.270(1)

–0.384(1)

–0.515(1)

–0.532(1)

–0.418(1)

–0.287(1)

0.800(3)

3.4(1)

3.1(1)

12.2(4)

13.4(5)

4.7(3)

8(2)

5.7(7)

5.9(7)

4.7(6)

4.9(6)

4(1)

6(1)

10(2)

9(1)

4.9

4.8

0.784(1)

0.710(2)

0.835(1)

0.6982(5)

0.6679(7)

0.5870(8)

0.5364(5)

0.5667(7)

0.6476(8)

0.8428(7)

0.8267(6)

0.8510(7)

0.8914(7)

0.9075(6)

0.8831(7)

0.8476(8)

0.7940(5)

0.8206(7)

0.9008(9)

0.9544(5)

0.9278(7)

0.338(1)

C(8)

C(9)

C(10)

C(11)

C(12)

C(13)

C(14)

C(15)

C(16)

C(17)

C(18)

C(19)

C(20)

C(21)

C(22)

C(23)

C(24)

C(25)

C(26)

C(27)

C(28)

C(29)

C(30)

C(31)

C(32)

C(33)

C(34)

C(35)

C(36)

C(37)

C(38)

C(39)

C(40)

C(41)

C(42)

C(43)

C(44)

C(45)

4.8

4.6

thermal parameters of non-hydrogen atoms, and fractional co-

ordinates and thermal parameters of hydrogen atoms have

been deposited.⁵

Results and discussion

4.6

The synthesis of bis(S-alkyl trithiocarbonato)dimethylger-

manes, 1–4, chloro(S-alkyl trithiocarbonato)diphenylger-

manes, 5–8, (O-alkyl monothiocarbonato)triphenylgermanes,

13–15, bis(O-alkyl monothiocarbonato)diphenylgermanes,

16–18, and (O-alkyl monothiocarbonato)trimethylgermanes,

19–21, can be readily achieved in 73–90% yield by the reac-

tion of the salt of the appropriate thiocarbonic acid in dried

CS₂, CH₃Cl, or CH₂Cl₂as solvent, or monothiocarbonic acid

in dried CH₂Cl₂as solvent with chlorotriphenylgermane, di-

chlorodiphenylgermane, or chlorotrimethylgermane using a

standard Schlenk line in accord with eqs. [1]–[5]:

3.2(9)

5(1)

8(1)

7.3(6)

4.7

4.4

4.7

0.352(1)

0.404(1)

0.357(1)

0.2056(5)

0.1705(7)

0.0891(8)

0.0427(5)

0.0778(7)

0.1593(8)

0.3550(8)

0.3017(5)

0.3286(7)

0.4090(8)

0.4623(5)

0.4354(7)

0.3539(7)

0.3349(6)

0.3599(7)

0.4039(7)

0.4228(6)

0.3978(7)

0.121(1)

[1]

[2]

Me₂GeCl₂+ 2KS₂CSR → Me₂Ge[S₂CSR]₂+ 2KCl

Ph₂GeCl₂+ KS₂CSR → Ph₂GeCl[S₂CSR] + KCl

(R = Et, i-Pr, n-Pr, n-Bu)

5

Copies of material deposited may be purchased from: The

Depository of Unpublished Data, Document Delivery, CISTI,

National Research Council Canada, Ottawa, ON K1A 0S2,

Canada. Tables of atomic coordinates have been deposited with

the Cambridge Crystallographic Centre, and can be obtained on

request from The Director, Cambridge Crystallographic Centre,

University Chemical Laboratory, 12 Union Road, Cambridge

CB2 1EZ, U.K. Structure factor amplitudes are no longer being

deposited and may be obtained directly from the author.

4.7

10(1)

324

Table 5. Final fractional coordinates and B(eq) for

Can. J. Chem. Vol. 76, 1998

Table 6. Interatomic distances (Å) and angles (deg) for

non-hydrogen atoms of Ph₂Ge[SCO₂Me]₂, 16 with standard

Me₂Ge[S₂CSEt]₂, 1.

deviations in parentheses.

Ge(1)—S(1)

Ge(1)—C(7)

S(1)—C(1)

S(2)—C(1)

S(3)—C(1)

S(3)—C(2)

C(2)—C(3)

Ge(1)—S(2)

Ge(1)—S(3)

2.296(4) Ge(1)—S(4)

1.93(1)

2.294(4)

Atom

x

y

z

B(eq)

1.78(1)

1.62(1)

1.71(1)

1.82(1)

1.48(2)

S(4)—C(4)

S(5)—C(4)

S(6)—C(4)

S(6)—C(5)

C(5)—C(6)

1.73(1)

1.63(2)

1.74(2)

1.81(2)

1.43(2)

3.051(5)

4.688(1)

Ge(1)

Ge(2)

S(1)

S(2)

S(3)

S(4)

O(1)

O(2)

O(3)

O(4)

O(5)

O(6)

O(7)

O(8)

C(1)

C(2)

C(3)

0.2414

0.7159(1)

0.9707(1)

0.8261(3)

0.5951(4)

0.8536(4)

1.0846(4)

0.925(1)

1.0076(9)

0.5159(8)

0.4248(9)

0.764(1)

0.6841(9)

1.1861(9)

1.259(1)

0.928(1)

1.096(2)

0.506(1)

0.342(2)

0.684(1)

0.615(1)

0.6047(9)

0.662(1)

0.731(1)

0.7414(9)

0.753(1)

0.804(1)

0.8335(8)

0.8121(9)

0.761(1)

0.7312(8)

0.758(1)

0.598(1)

1.184(1)

1.350(2)

1.004(1)

1.0670(9)

1.0849(8)

1.039(1)

0.976(1)

0.9578(8)

0.9442(9)

0.8710(8)

0.8545(7)

0.9111(9)

0.9842(8)

1.0007(8)

0.3834

3.31(8)

3.38(9)

4.9(3)

5.0(3)

5.2(3)

4.9(3)

5.9(8)

6.3(8)

5.4(8)

5.5(7)

5.8(8)

6.3(8)

5.8(8)

8(1)

5(1)

12(2)

3.6(9)

9(2)

5.9

5.3

5(1)

7(1)

4(1)

9(2)

5.3

4.5

–0.0090(2)

0.2911(5)

0.2123(5)

0.0181(5)

–0.0514(5)

0.292(1)

0.334(2)

0.160(1)

0.142(1)

0.052(1)

0.090(1)

–0.050(1)

–0.103(2)

0.304(2)

0.353(3)

0.168(2)

0.102(2)

0.368(1)

0.454(1)

0.543(1)

0.547(1)

0.462(1)

0.372(1)

0.1002(8)

0.024(1)

–0.080(1)

–0.1091(8)

–0.033(1)

0.071(1)

0.056(2)

0.122(2)

–0.069(2)

–0.126(3)

0.1297(9)

0.211(1)

0.311(1)

0.3297(9)

0.248(1)

0.148(1)

–0.1376(8)

–0.214(1)

–0.3113(9)

–0.3332(8)

–0.257(1)

–0.1595(9)

0.08263(9)

0.4521(2)

0.4470(2)

0.0163(2)

0.0145(2)

0.3547(6)

0.4359(6)

0.3450(6)

0.4237(5)

0.1165(6)

0.0344(6)

0.1118(7)

0.0293(7)

0.405(1)

3.246(5) Ge(1)—S(5)

4.756(4) Ge(1)—S(6)

S(1)-Ge(1)-S(4)

S(1)-Ge(1)-C(7)

S(4)-Ge(1)-C(7)

Ge(1)-S(1)-C(1)

S(1)-C(1)-S(2)

S(1)-C(1)-S(3)

S(2)-C(1)-S(3)

C(1)-S(3)-C(2)

S(3)-C(2)-C(3)

S(1)-Ge(1)—S(2)

90.0(1)

107.9(3)

109.6(3)

100.8(4)

124.1(8)

108.7(7)

127.2(9)

103.2(7)

108(1)

C(7)-Ge(1)-C(7)^a

125.8(6)

S(1)-Ge(1)-C(7)^a

S(4)-Ge(1)-C(7)^a

Ge(1)-S(4)-C(4)

S(4)-C(4)-S(5)

S(4)-C(4)-S(6)

S(5)-C(4)-S(6)

C(4)-S(6)-C(5)

S(6)-C(5)-C(6)

S(4)-Ge(1)—S(5)

107.9(3)

109.6(3)

96.3(6)

125(1)

110.5(9)

125.0(9)

101.7(8)

111(2)

0.401(2)

0.396(1)

0.387(1)

62.9(1)

65.8(1)

C(4)

C(5)

C(6)

C(7)

C(8)

C(9)

^ax, 1/2 – y, z.

0.3368(6)

0.3490(5)

0.3119(6)

0.2625(6)

0.2503(5)

0.2874(6)

0.3443(5)

0.3777(4)

0.3536(5)

0.2962(5)

0.2628(4)

0.2869(5)

0.065(1)

Table 7. Interatomic distances (Å) and angles (deg) for

Ph₃Ge[SCO₂Me], 13.

Ge(1)—S(1)

Ge(1)—C(9)

S(1)—C(1)

O(2)—C(1)

Ge(1)—O(1)

2.253(3) Ge(1)—C(3)

1.946(9) Ge(1)—C(15)

1.77(1) O(1)—C(1)

1.32(1) O(2)—C(2)

3.112(7) Ge(1)—O(2)

1.931(9)

1.950(9)

1.19(1)

1.45(1)

4.331(7)

C(10)

C(11)

C(12)

C(13)

C(14)

C(15)

C(16)

C(17)

C(18)

C(19)

C(20)

C(21)

C(22)

C(23)

C(24)

C(25)

C(26)

C(27)

C(28)

C(29)

C(30)

C(31)

C(32)

S(1)-Ge(1)-C(3)

S(1)-Ge(1)-C(15)

C(3)-Ge(1)-C(9)

Ge(1)-S(1)-C(1)

S(1)-C(1)-O(1)

Ge(1)-C(3)-C(4)

Ge(1)-C(9)-C(10)

Ge(1)-C(15)-C(16) 119.9(7)

O(1)-C(1)-O(2)

O(1)—Ge(1)-C(3)

O(1)—Ge(1)-C(15) 155.5(3)

110.6(3)

S(1)-Ge(1)-C(9)

112.8(3)

100.4(3)

112.8(4)

99.6(4)

125.9(8)

121.8(7)

122.1(8)

C(3)-Ge(1)-C(15) 110.1(4)

C(9)-Ge(1)-C(15) 109.4(4)

C(1)-O(2)-C(2)

S(1)-C(1)-O(2)

Ge(1)-C(3)-C(8)

115.1(8)

107.8(7)

119.1(7)

0.070(1)

0.0609(9)

0.061(1)

Ge(1)-C(9)-C(14) 119.2(8)

Ge(1)-C(15)-C(20) 120.1(7)

0.1240(5)

0.1032(4)

0.1356(5)

0.1888(5)

0.2096(4)

0.1772(5)

0.1294(5)

0.1116(4)

0.1420(5)

0.1903(5)

0.2081(4)

0.1776(5)

126.0(1)

75.4(3)

S(1)-Ge(1)—O(1)

O(1)—Ge(1)-C(9)

56.4(1)

89.0(3)

eqs. [1], [3], [4], and [5] and exact stoichiometric amounts in

eq. [2] to favor the formation of the mixed chloro derivatives.

It is essential that the trithiocarbonate salts be carefully repu-

rified before use to avoid side reactions leading to polysulfides

(23), but monothiocarbonate salts can be used as prepared pro-

vided pure dry alcohol was used in their preparation.

Chloro(S-alkyl trithiocarbonato)diphenylgermanes react

readily in situ with bromotrimethylsilane in CS₂or CH₂Cl₂to

give bromo(S-alkyl trithiocarbonato)diphenylgermanes, 9–12,

in accord with eq. [6]. An excess of Me₃SiBr is used as both

it and Me₃SiCl are readily volatile and so are easily separated

from the products.

4.5

[3]

[4]

[5]

Ph₃GeCl + NaSCO₂R → Ph₃Ge[SCO₂R] + NaCl

Ph₂GeCl₂+ 2NaSCO₂R → Ph₂Ge[SCO₂R]₂+ 2NaCl

Me₃GeCl + NaSCO₂R →Me₃Ge[SCO₂R] + NaCl

(R = Me, i-Pr, n-Pr)

[6]

Ph₂GeCl[S₂CSR] + Me₃SiBr

→ Ph₂GeBr[S₂CSR] + Me₃SiCl

The salts are used in considerable excess relative to the

stoichiometric requirements to ensure complete reaction in

(R = Et, i-Pr, n-Pr, n-Bu)

325

Drake and Yang

Table 8. Interatomic distances (Å) and angles (deg) for

Ph₃Ge[SCO₂(i-Pr)], 14.

Table 9. Interatomic distances (Å) and angles (deg) for

Ph₂Ge[SCO₂Me]₂, 16.

Ge(1)—S(1)

Ge(1)—C(5)

Ge(1)—C(11)

Ge(1)—C(17)

S(1)—C(1)

O(1)—C(1)

O(2)—C(1)

O(2)—C(2)

C(2)—C(3)

C(2)—C(4)

Ge(1)—O(1)

Ge(1)—O(2)

2.251(5) Ge(2)—S(2)

1.93(1) Ge(2)—C(27)

1.94(1) Ge(2)—C(33)

1.94(1) Ge(2)—C(39)

1.78(2) S(2)—C(23)

1.23(2) O(3)—C(23)

1.28(3) O(4)—C(23)

1.48(3) O(4)—C(24)

1.48(4) C(24)—C(25)

1.51(3) C(24)—C(26)

3.10(2) Ge(2)—O(3)

4.27(2) Ge(2)—O(4)

2.256(5)

1.940(9)

1.94(1)

1.80(2)

1.16(2)

1.38(2)

1.44(3)

1.47(4)

1.51(3)

3.13(2)

4.34(1)

Ge(1)—S(1)

Ge(1)—S(2)

Ge(1)—C(5)

Ge(1)—C(11)

S(1)—C(1)

S(2)—C(3)

O(1)—C(1)

O(2)—C(1)

O(2)—C(2)

O(3)—C(3)

O(4)—C(3)

O(4)—C(4)

Ge(1)—O(1)

Ge(1)—O(2)

Ge(1)—O(3)

Ge(1)—O(4)

2.257(5) Ge(2)—S(3)

2.255(5) Ge(2)—S(4)

1.93(1) Ge(2)—C(21)

1.93(1) Ge(2)—C(27)

1.78(2) S(3)—C(17)

1.77(2) S(4)—C(19)

1.18(3) O(5)—C(17)

1.34(2) O(6)—C(17)

1.47(3) O(6)—C(18)

1.19(3) O(7)—C(19)

1.33(2) O(8)—C(19)

1.48(3) O(8)—C(20)

3.00(1) Ge(2)—O(5)

4.30(1) Ge(2)—O(6)

3.03(1) Ge(2)—O(7)

4.27(1) Ge(2)—O(8)

2.255(6)

2.264(5)

1.92(1)

1.93(1)

1.77(2)

1.76(2)

1.20(3)

1.31(3)

1.49(3)

1.20(3)

1.32(2)

1.47(3)

3.02(1)

4.26(1)

3.07(1)

4.28(2)

S(1)-Ge(1)-C(5)

S(1)-Ge(1)-C(11)

S(1)-Ge(1)-C(17)

C(5)-Ge(1)-C(11)

C(5)-Ge(1)-C(17)

108.4(4)

113.2(4)

99.4(3)

S(2)-Ge(2)-C(27)

S(2)-Ge(2)-C(33)

S(2)-Ge(2)-C(39)

108.3(4)

100.8(3)

112.7(4)

112.5(5)

112.1(5)

C(27)-Ge(2)-C(33) 111.4(6)

C(27)-Ge(2)-C(39) 113.7(5)

C(11)-Ge(2)-C(39) 109.3(6)

S(1)-Ge(1)-S(2)

S(1)-Ge(1)-C(5)

S(1)-Ge(1)-C(11)

S(2)-Ge(1)-C(5)

S(2)-Ge(1)-C(11)

C(5)-Ge(1)-C(11)

Ge(1)-S(1)-C(1)

S(1)-C(1)-O(1)

S(1)-C(1)-O(2)

O(1)-C(1)-O(2)

C(1)-O(2)-C(2)

Ge(1)-S(2)-C(3)

S(2)-C(3)-O(3)

S(2)-C(3)-O(4)

O(3)-C(3)-O(4)

C(3)-O(4)-C(4)

Ge(1)-C(5)-C(6)

Ge(1)-C(5)-C(10)

93.9(2) S(3)-Ge(2)-S(4)

92.6(2)

111.6(4)

112.7(4)

110.5(4)

111.5(4)

C(11)-Ge(1)-C(17) 110.5(6)

111.4(4)

S(3)-Ge(2)-C(21)

S(3)-Ge(2)-C(27)

S(4)-Ge(2)-C(21)

S(4)-Ge(2)-C(27)

Ge(1)-S(1)-C(1)

S(1)-C(1)-O(1)

S(1)-C(1)-O(2)

O(1)-C(1)-O(2)

C(1)-O(2)-C(2)

O(2)-C(2)-C(3)

O(2)-C(2)-C(4)

C(3)-C(2)-C(4)

Ge(1)-C(5)-C(6)

Ge(1)-C(5)-C(10)

Ge(1)-C(11)-C(12) 121(1)

Ge(1)-C(11)-C(16) 119.4(9)

Ge(1)-C(17)-C(18) 120(1)

Ge(1)-C(17)-C(22) 120.3(9)

S(1)-Ge(1)—O1()

O(1)—Ge(1)-C(5)

100.5(6)

123(2)

110(2)

127(2)

117(2)

107(2)

105(2)

115(2)

119.8(8)

120(1)

Ge(2)-S(2)-C(23)

S(2)-C(23)-O(3)

S(2)-C(23)-O(4)

O(3)-C(23)-O(4)

C(23)-O(4)-C(24)

O(4)-C(24)-C(25)

O(4)-C(24)-C(26)

C(25)-C(24)-C(26) 112(2)

Ge(2)-C(27)-C(28) 122.2(8)

Ge(2)-C(27)-C(32) 118(1)

Ge(2)-C(33)-C(34) 120(1)

Ge(2)-C(33)-C(38) 119.7(9)

Ge(2)-C(39)-C(40) 124(1)

Ge(2)-C(39)-C(44) 116.4(9)

98.3(6)

128(2)

105(1)

127(2)

114(1)

111(2)

107(2)

110.7(4)

109.9(5)

110.4(4)

117.9(5)

96.8(7)

124(1)

110(2)

126(2)

115(2)

96.5(7)

127(1)

109(1)

124(2)

116(2)

127(1)

112.5(9)

C(21)-Ge(2)-C(27) 115.7(5)

Ge(2)-S(3)-C(17)

S(3)-C(17)-O(5)

S(3)-C(17)-O(6)

O(5)-C(17)-O(6)

C(17)-O(6)-C(18)

Ge(2)-S(4)-C(19)

S(4)-C(19)-O(7)

S(4)-C(19)-O(8)

O(7)-C(19)-O(8)

C(19)-O(8)-C(20)

97.3(7)

125(2)

107(2)

128(2)

113(2)

97.8(7)

127(1)

108(1)

125(2)

116(2)

56.7(3)

72.9(5)

S(2)-Ge(2)—O3()

O(2)—Ge(2)-C(27)

56.8(3)

77.9(5)

Ge(2)-C(21)-C(22) 123.8(9)

Ge(2)-C(21)-C(26) 116.2(8)

Ge(2)-C(27)-C(28) 118.5(8)

Ge(2)-C(27)-C(32) 121.4(8)

O(1)—Ge(1)-C(11) 88.6(5)

O(1)—Ge(1)-C(17) 154.8(4)

O(2)—Ge(2)-C(33) 157.5(4)

O(2)—Ge(2)-C(39) 83.6(5)

Ge(1)-C(11)-C(12) 115.4(9)

Ge(1)-C(11)-C(16) 124.6(9)

S(1)-Ge(1)—O(1)

S(2)-Ge(1)—O(3)

S(2)-Ge(1)—O(1)

S(1)-Ge(1)—O(3)

58.1(1)

58.3(1)

151.9(3)

152.1(3)

S(3)-Ge(2)—O(5)

S(4)-Ge(2)—O(7)

S(4)-Ge(2)—O(5)

S(3)-Ge(2)—O(7)

58.1(3)

57.3(3)

150.7(3)

149.6(3)

In general, all of the compounds are susceptible to moisture

and air on exposure to the atmosphere, as was found for the

corresponding dithiocarbonates as well as for the related

trithiocarbonates reported earlier (15). This appears to be es-

pecially true for the bis-diphenyl derivatives, 16–18, where the

formation of crystals of (Ph₂GeO)₃, the ring trimer of

diphenylgermanium oxide, was confirmed by X-ray crystal-

lography (26) when solutions of Ph₂Ge[SCO₂R]₂species in

CH₂Cl₂are evaporated over several days while exposed to

moist air. In addition, the trithiocarbonates, 1–12, charac-

teristically readily undergo carbon disulfide elimination at

room temperature in accord with eqs. [7]–[9], so that all of the

compounds are stored at –15°C in sealed containers.

O(1)—Ge(1)—O(3) 149.4(4)

O(5)—Ge(2)—O(7) 152.0(4)

was therefore used as the preferred solvent for recording NMR

spectra.

Carbon disulfide elimination

In all cases, for 2–12, attempts to distill the yellow oils under

vacuum or to warm them to obtain their boiling points resulted

in the rapid expulsion of CS₂. As found with the

Ph₃Ge[S₂CSR] species (15), the H and ¹³C NMR spectra of

1

sealed samples of solutions of compounds 1–12 held at room

temperature showed a steady decrease in intensity of the sig-

nals attributable to Me₂Ge[S₂CSR]₂, 1–4, or Ph₂XGe[S₂CSR],

5–12, species. Typically, in the ¹³C NMR spectra, a peak at

192.7 ppm, attributable to CS₂, soon appeared and steadily

increased in intensity with time as the peak originally observed

in the range 225.68–226.70 ppm for 1–4 and 217.35–224.86

[7]

[8]

[9]

Ph₂GeX[S₂CSR] → Ph₂GeX[SR] + CS₂

Me₂Ge[S₂CSR]₂→ Me₂Ge[S₂CSR][SR] + CS₂

Me₂Ge[S₂CSR][SR] → Me₂Ge[SR]₂+ CS₂

All compounds were readily dissolved in chloroform, which

326

Can. J. Chem. Vol. 76, 1998

Table 10. ¹H chemical shifts in the NMR spectra of compounds 1–4 as well as the decomposition products Me₂Ge[S₂CSR][SR], where R = Et,

i-Pr, n-Pr, and n-Bu.^a–c

Ge-CH₃

S-CH_n

SC-CH_n′

1.20 (6H, t, 7.4)

SCC-CH₃′′

Compounds

Me₂Ge[S₂CSEt]₂, 1

1.43 (s) 3.06 (4H, q, 7.4)

Me₂Ge[S₂CS(i-Pr)]₂, 2

Me₂Ge[S₂CS(n-Pr)]₂, 3

Me₂Ge[S₂CS(n-Bu)]₂, 4^d

Me₂Ge[S₂CSEt][SEt]

1.43 (s) 3.68 (2H, sept, 6.9)

1.42 (s) 3.04 (4H, t, 7.4)

1.42 (s) 3.08 (4H, t, 7.3)

1.26 (12H, d, 6.9)

1.58 (4H, m, 7.4, 7.3)

1.54 (4H, m ,7.3, 7.3)

1.30 (3H, t, 7.4) 1.28 (3H, t, 7.4)

0.90 (6H, t, 7.3)

1.31 (4H, m, 7.3, 7.3)

1.11 (s) 3.20 (2H, q, 7.4) 2.65 (2H, q, 7.4)

Me₂Ge[S₂CS(i-Pr)][S(i-Pr)] 1.12 (s) 3.88 (1H, sept, 6.8) 3.27 (1H, sept, 6.6) 1.36 (6H, d, 6.8) 1.37 (6H, d, 6.6)

Me₂Ge[S₂CS(n-Pr)][S(n-Pr)] 1.10 (s) 3.18 (2H, t, 7.3) 2.59 (2H, t, 7.3)

Me₂Ge[S₂CS(n-Bu)][S(n-Bu)]^e1.08 (s) 3.18 (2H, t, 7.4) 2.58 (2H, t, 7.4)

1.69 (2H, m) 1.61 (2H, m)

1.62 (2H, m) 1.59 (2H, m)

0.98 (3H, t, 7.5) 0.96 (3H, t, 7.5)

1.39 (2H, m) 1.37 (2H, m)

^aThe spectra were recorded in CDCl₃and are reported in ppm from Me₄Si, using CHCl₃as a second standard.

^bMultiplicities (s = singlet, d = doublet, t = triplet, sept = septet, m = multiplet), and coupling constants in Hz are given in parentheses.

^cPeaks attributable to [SR] groups are in italics.

^dPeaks also assigned to SC₃-CH₃“ at 0.86 (6H, t, 7.3).

^ePeaks also assigned to SC₃-CH₃“ are seen at 0.89 (3H, t, 7.0) and 0.97 (3H, t, 7.3).

Table 11. ¹³C chemical shifts in the NMR spectra of compounds 1–4 as well as the decomposition products Me₂Ge[S₂CSR][SR]

where R = Et, i-Pr, n-Pr, and n-Bu.^a

Compounds

Ge-C

S-C

34.16

44.96

41.89

39.79

33.84 (22.60)

44.45 (34.35)

41.56 (30.28)

39.40 (35.15)

SC-C

12.70

21.73

21.29

29.74

12.69 (18.68)

21.73 (27.82)

21.29 (26.46)

29.81 (27.91)

SC₂-C

SC₃-C

S₂CS

Me₂Ge[S₂CSEt]₂, 1

9.83

9.92

9.86

9.87

5.82

6.21

5.88

5.83

226.11

225.68

226.28

226.26

226.53

226.12

226.70

226.64

Me₂Ge[S₂CS(i-Pr)]₂, 2

Me₂Ge[S₂CS(n-Pr)]₂, 3

Me₂Ge[S₂CS(n-Bu)]₂, 4

Me₂Ge[S₂CSEt][SEt]

Me₂Ge[S₂CS(i-Pr)][S(i-Pr)]

Me₂Ge[S₂CS(n-Pr)][S(n-Pr)]

Me₂Ge[S₂CS(n-Bu)][S(n-Bu)]

13.64

22.22

13.72

13.84 (13.43)

21.83 (22.22)

13.72 (13.55)

^aThe spectra are recorded in CDCl₃and are reported in ppm from Me₄Si.

Table 12. ¹H chemical shifts in the NMR spectra of compounds 5–12. ^a–c

Compounds

Ge-C₆H₅

S-CH_n

SC-CH_n′

SCC-CH₃′′

Ph₂GeCl[S₂CSEt], 5

7.88–7.85 (4H) 7.53–7.45 (6H)

7.86–7.83 (4H) 7.49–7.46 (6H)

7.87–7.84 (4H) 7.50–7.45 (6H)

7.86–7.83 (4H) 7.52–7.47 (6H)

7.73–7.70 (4H) 7.51–7.47 (6H)

7.75–7.72 (4H) 7.51–7.49 (6H)

7.72–7.69 (4H) 7.49–7.46 (6H)

7.73–7.71 (4H) 7.50–7.49 (6H)

3.13 (2H, q, 7.4)

3.71 (1H, sept, 6.9)

3.10 (2H, t, 7.3)

3.11 (2H, t, 7.4)

3.26 (2H, q, 7.4)

3.92 (1H, sept, 6.9)

3.21 (2H, t, 7.3)

3.25 (2H, t, 7.4)

1.28 (3H, t, 7.5)

1.34 (6H, d, 6.9)

1.66 (2H, m, 7.3, 7.4)

1.60 (2H, m, 7.4, 7.5)

1.33 (3H, t, 7.4)

1.39 (6H, d, 6.9)

1.70 (2H, m, 7.3, 7.3)

1.67 (2H, m, 7.4, 7.5)

Ph₂GeCl[S₂CS(i-Pr)], 6

Ph₂GeCl[S₂CS(n-Pr)], 7

Ph₂GeCl[S₂CS(n-Bu)], 8

Ph₂GeBr[S₂CSEt], 9

Ph₂GeBr[S₂CS(i-Pr)], 10

Ph₂GeBr[S₂CS(n-Pr)], 11

Ph₂GeBr[S₂CS(n-Bu)], 12

0.95 (3H, t, 7.4)

1.35 (2H, m, 7.5, 7.3)

0.99 (3H, t, 7.3)

1.42 (2H, m, 7.5, 7.3)

^aThe spectra were recorded in CDCl₃and are reported in ppm from Me₄Si, using CHCl₃as a second standard.

^bNumber of protons, multiplicities (d = doublet, t = triplet, sept = septet, m = multiplet), and coupling constants in Hz are given in parentheses.

^cPeaks also assigned to SC₃-CH₃“ at 0.87 (3H, t, 7.3) for 8 and at 0.93 (3H, t, 7.3) for 12.

Table 13. ¹³C chemical shifts in the NMR spectra of compounds, 5–12.^a,b

Compounds

Ge-C₆

S-C

SC-C

SC₂-C

S₂CS

Ph₂GeCl[S₂CSEt], 5

135.60, 133.77, 131.17, 128.88

135.71, 133.73, 131.08, 128.84

135.60, 133.76, 131.14, 128.88

135.59, 133.73, 131.11, 128.84

135.38, 132.79, 131.76, 129.04

135.38, 132.79, 131.62, 129.10

135.31, 132.75, 131.79, 129.04

135.38, 132.79, 131.76, 129.04

34.51

45.56

42.21

40.11

33.90

45.02

41.53

39.46

12.55

21.64

21.13

29.53

12.74

21.7

224.63

224.27

224.86

224.83

217.64

217.35

217.92

217.81

Ph₂GeCl[S₂CS(i-Pr)], 6

Ph₂GeCl[S₂CS(n-Pr)], 7

Ph₂GeCl[S₂CS(n-Bu)], 8

Ph₂GeBr[S₂CSEt], 9

Ph₂GeBr[S₂CS(i-Pr)], 10

Ph₂GeBr[S₂CS(n-Pr)], 11

Ph₂GeBr[S₂CS(n-Bu)], 12

13.58

22.18

21.3

29.77

13.5

22.16

^aThe spectra are recorded in CDCl₃and are reported in ppm from Me₄Si.

^bPeaks attributable to SC₃-C are seen at 13.63 for 8 and at 13.71 for 12.

327

Drake and Yang

Table 14. ¹H chemical shifts in the NMR spectra of compounds 13–21.^a,b

Compounds Ge-C₆H₅/CH₃O-CH_n

7.64–7.61 (6H) 7.44–7.40 (9H) 3.58 (3H, s)

7.64–7.61 (6H) 7.41–7.36 (9H) 4.86 (1H, sept, 6.4) 0.96 (6H, d, 6.4)

OC-CH_n

OCC-CH₃

Ph₃Ge[SCO₂Me], 13

Ph₃Ge[SCO₂(i-Pr)], 14

Ph₃Ge[SCO₂(n-Pr)], 15

Ph₂Ge[SCO₂Me]₂, 16

Ph₂Ge[SCO₂(i-Pr)]₂, 17

Ph₂Ge[SCO₂(n-Pr)]₂, 18

Me₃Ge[SCO₂Me], 19

Me₃Ge[SCO₂(i-Pr)], 20

Me₃Ge[SCO₂(n-Pr)], 21

7.64–7.61 (6H) 7.43–7.39 (9H) 3.93 (2H, t, 6.8)

7.79–7.76 (4H) 7.48–7.45 (6H) 3.59 (6H, s)

1.42 (2H, m)

0.73 (3H, t, 7.4)

0.75 (6H, t, 7.4)

0.89 (3H, t, 7.4)

7.79–7.76 (4H) 7.45–7.43 (6H) 4.85 (2H, sept, 6.2) 0.99 (12H, d, 6.2)

7.79–7.76 (4H) 7.49–7.43 (6H) 3.94 (4H, t, 6.9) 1.45 (4H, m)

0.57 (9H)

0.54 (9H)

0.59 (9H)

3.65 (3H, s)

4.91 (1H, sept, 6.3) 1.17 (6H, d, 6.3)

4.04 (2H, t, 6.6) 1.62 (2H, m)

^aThe spectra were recorded in CDCl₃and are reported in ppm from Me₄Si, using CHCl₃as a second standard.

^bNumber of protons, multiplicities (d = doublet, t = triplet, sept = septet, m = multiplet), and coupling constants in Hz are given in

parentheses.

Table 15. ¹³C chemical shifts in the NMR spectra of compounds 13–21.^a

Compounds

Ge-C₆H₅/CH₃

O-C

OC-C

OC₂-C

SCO₂

Ph₃Ge[SCO₂Me], 13

134.74, 134.51, 130.14, 128.63

134.83, 134.71, 130.04, 128.56

134.71, 134.65, 130.07, 128.59

134.30, 133.93, 130.92, 128.70

134.61, 133.90, 130.76, 128.70

134.31, 133.92, 130.82, 128.72

2.06

54.39

72.20

69.51

54.75

72.97

69.97

53.89

71.23

68.90

169.32

168.05

168.80

168.61

167.28

168.08

170.80

169.49

170.35

Ph₃Ge[SCO₂(i-Pr)], 14

Ph₃Ge[SCO₂(n-Pr)], 15

Ph₂Ge[SCO₂Me]₂, 16

Ph₂Ge[SCO₂(i-Pr)]₂, 17

Ph₂Ge[SCO₂(n-Pr)]₂, 18

Me₃Ge[SCO₂Me], 19

Me₃Ge[SCO₂(i-Pr)], 20

Me₃Ge[SCO₂(n-Pr)], 21

21.48

21.88

10.18

10.15

10.38

21.48

21.83

2.21

2.13

21.90

22.09

^aThe spectra were recorded in CDCl₃and reported in ppm from Me₄Si.

Table 16. Selected features and their assignments in the vibrational spectra of compounds 1–4.^a,b

Me₂Ge[S₂CSEt]₂, 1 Me₂Ge[S₂CS(i-Pr)]₂, 2 Me₂Ge[S₂CS(n-Pr)]₂, 3

Me₂Ge[S₂CS(n-Bu)]₂, 4

IR

[Raman]

IR

[Raman]

IR

[Raman]

IR

[Raman]

Assignment

1066 s

1033 s

858 vs sh

826 s

623 m

569 w

509 w

407 m sh

360 m

314 m

194 w

[1072 (100)]

[1026 (67]

[n.o.]

1067 vs

1040 vs

880 vs sh

808 vs

627 m

616 m

531 w

406 m sh

360 w

329 s

[1069 (55)]

[1039 (100)]

[n.o.]

1077 s

1043 vs

860 s sh

819 vs

626 m

580 m

510 w

416 m

373 m

319 m

191 w

[1078 (60)]

[1043 (100)]

[n.o.]

1083 vs

1045 vs

860 s

811 vs

626 m

578 m

509 m

406 m

388 s

[1082 (50)]

[1047 (100)]

[n.o.]

ν(S₂CSC)_a

ν(S₂CSC)_b

ν(H₃CGe)

ν(S₂CSC)_c

ν(Ge-C)_asym

ν(Ge-C)_sym

ν(S₂CSC)_d

ν(Ge-S)_asym

ν(Ge-S)_sym

δ(S₂CSC)

ρ(S₂CSC)

[827 (50)]

[621 (20)]

[577 (65)]

[512 (65)]

[407 (54)]

[365 (35)]

[319 (20)]

[190 (50)]

[811 (5)]

[815 (15)]

[626 (20)]

[578 (50)]

[511 (80)]

[415 (50)]

[365 (40)]

[321 (15)]

[191 (75)]

[802 (25)]

[624 (35)]

[577 (50)]

[512 (75)]

[405 (55)]

[384 (20)]

[324 (10)]

[189 (75)]

[626 (20)]

[578 (40)]

[530 (70)]

[405 (50)]

[364 (30)]

[324 (20)]

[195 (50)]

328 m

191 s

213 m

^aParentheses denote relative intensities in the Raman effect.

^bs = strong, m = medium, w = weak, sh = shoulder, br = broad, and v = very.

ppm for 5–12, attributable to the S₂CS carbon, decreased in

intensity to eventually disappear. As with the Ph₂Ge[S₂CSR]₂

series, more complicated spectra were observed between the

NMR spectra of the freshly prepared Me₂Ge[S₂CSR]₂species,

1–4, and the final spectra that contained only peaks attributable

to CS₂and Me₂Ge[SR]₂. The additional peaks were entirely

consistent with the formation of the intermediate

attributable to Ph₂GeX[S₂CSR] being totally lost in 1–2 days

to be replaced by peaks attributable to the corresponding

Ph₂GeX[SR] compounds.

Nuclear magnetic resonance spectra

1

For Me₂Ge[S₂CSR]₂, 1–4, the H NMR chemical shifts (Ta-

ble 10) of methyl attached to Ge are similar for all trithiocar-

bonate derivatives, being dependent on the number of groups

attached to Ge rather than the alkyl group of the ligand. Thus,

the chemical shifts of CH₃-Ge are at 1.42–1.43 ppm for 1–4

compared to 0.71–0.73 ppm for Me₃Ge[S₂CSR] (15). The

same phenomenon was noted for Me₂Ge[S₂CNMe₂]₂and

1

Me₂Ge[S₂CSR][SR] compounds, whose relevant H and ¹³C

NMR data are also presented in Tables 10 and 11, respectively.

For the three derivatives that are oils, 2–4, CS₂elimination is

complete after approximately 5 days. The halodiphenyl deriva-

tives 5–12 decompose even more rapidly, the original signals

328

Can. J. Chem. Vol. 76, 1998

Me₃Ge[S₂CNMe₂], suggesting the group electronegativities of

trithiocarbonates and dithiocarbamates are similar (6). In gen-

eral, all alkyl group peaks of the ligands have the fine structure

and relative intensities expected for first-order spectra, except

of course for the central CH₂groups in n-propyl and n-butyl.

The phenyl signals in Ph₂GeCl[S₂CSR], 5–8, are very similar

in appearance and position to those reported for

Ph₂Ge[S₂CSR]₂(15) while those of Ph₂GeBr[S₂CSR], 9–12,

are similar to Ph₃Ge[S₂CSR] derivatives (Table 12). The

chemical shifts within the ligands of these halo derivatives

have values that differ systematically from the bis-diphenyl

compounds, the proton shifts being increasingly upfield in the

order bis < Cl < Br. The similarity of all spectra suggests the

trithiocarbonate groups are in identical environments in all

compounds 1–12.

19–21, the CH₃-Ge chemical shifts hardly vary, the values

being slightly less than those reported for Me₃Ge[S₂CNMe₂]

and the Me₃Ge[S₂CSR] derivatives (15), which is consistent

with the group electronegativity of monothiocarbonates being

slightly larger than those of dithiocarbamates (6) and trithio-

carbonates. The similarity of all of the spectra again indicates

that the environments of the monothiocarbonate groups in so-

lution are identical in 13–21.

In the ¹³C NMR spectra, the chemical shifts of monothio-

carbonate alkyl groups are again similar regardless of the

number or nature of groups attached to germanium. The

chemical shifts for the carbon atom of the SCO₂groups in

13–21 range from 167.28 to 170.80 ppm, compared to 207.04

to 212.12 ppm for a variety of S₂CO groups, and 221.36 to

226.41 ppm for the S₂CS groups in the analogous trithiocar-

bonates. The (CH₃)₃Ge chemical shifts are similar for 19, 20,

and 21 and are close to those of the analogous dithiocarbonates

(11, 12) and trithiocarbonates. The general similarity of the

values of the ¹³C NMR chemical shifts in 13–21 is again con-

sistent with the presence of similar monothiocarbonate link-

ages in solution.

In the ¹³C NMR spectra (Tables 11 and 13) the chemical

shifts of the alkyl groups in the ligand are relatively similar

regardless of the nature (methyl or phenyl) or number of

groups attached to germanium. Comparison with the corre-

sponding S₂COR derivatives (12, 13) indicates similar values

for chemical shifts of all alkyl carbon atoms except for those

directly attached to the sulfur atom, the difference in shift be-

ing consistently ca. 35 ppm as illustrated by that of CH₂in

Me₂Ge[S₂CSCH₂CH₃]₂(33.84) and Me₂Ge[S₂COCH₂CH₃]₂

(71.10 ppm) (12). In contrast, there is an upfield shift of ca. 14

ppm for the central trithiocarbonate carbon atom so that S₂CS

has chemical shifts of 225.68–226.28 ppm for 1–4 (Table 11)

compared to 207.04–212.12 ppm for S₂CO in related dithio-

carbonates (12, 13). For 5–12 (Table 13), the chemical shifts

in ligands are basically the same as in the corresponding bis

compounds, while for the S₂CS carbon in Ph₂GeCl[S₂CSR]

the shift is downfield relative to Ph₂Ge[S₂CSR]₂(15) by ca. 2

ppm, but is upfield by ca. 5 ppm for Ph₂GeBr[S₂CSR]. As

Infrared and Raman spectra

Distinctive features in the infrared and Raman spectra and their

assignments are given in Table 16 for Me₂Ge[S₂CSR]₂, 1–4,

and in Table 17 for Ph₂GeCl[S₂CSR], 5–8, and

Ph₂GeBr[S₂CSR], 9–12. The assignments in the tables make

use of such factors as the distinctive strong methyl germanium

rocking mode at approximately 850 cm^–1(11); the pairs of

fingerprints of decreasing intensity at ca. 740 and 695 cm^–1,

460 and 335 cm^–1, and 1435 and 1095 cm^–1in the infrared

spectra for phenyl germanes and the very intense Raman peak

close to 1000 cm^–1(12); comparisons with the spectra of pre-

viously reported related organogermanium trithiocarbonates;

comparisons with the spectra of the starting salts, KS₂CSR;

and the decrease in intensity of strong bands in the spectra of

all of the compounds 1–24 as CS₂elimination occurs. The

labelling of the phenyl modes uses the Wiffen convention (27).

Typical values for CTS and C–S stretching vibrations are

1090 and 700 cm^–1, respectively, so assigning four specific

stretches as ν(STCS₂), ν(S₂C–SR), ν(S₂CS–C), and

ν(GeS–CS₂) is not reasonable because the average positions

of ν(S₂CSC)_a, ν(S₂CSC)_b, ν(S₂CSC)_c, and ν(S₂CSC)_dare

1069, 1044, 826, and 515 cm^–1, respectively. Their similarity

in all derivatives suggests that all are strongly coupled in a

similar fashion and all have structures similar to those of

Me₂Ge[S₂CSEt]₂, 1, and Ph₂Ge[S₂CS(i-Pr)]₂(15). The assign-

ment of ν(S₂CSC)_dat ca. 515 cm^–1is close to that of the sym-

1

noted for the H NMR spectra, the consistencies in the ¹³C

NMR spectra point to similar trithiocarbonate environments in

compounds 1–12.

The ¹H and ¹³C NMR spectral data for monothiocarbonate

compounds 13–21 are presented in Tables 14 and 15, respec-

1

tively. The H NMR spectra recorded in CDCl₃confirm that

the products are over 98% pure relative to any hydrogen-con-

taining impurities and integration ratios are as expected. The

signals due to the phenyl groups in compounds 13–18 (two sets

of peaks between 7.36 and 7.79 ppm) are very similar in ap-

pearance and position to those of the analogous dithiocarbon-

ate and trithiocarbonate series (15) as well as other

phenylgermanium derivatives containing Ge—S bonds, so

once again the chemical shifts are dependent on the presence

of the Ge—S link(s) rather than the nature of the thiocarbonate

groups attached to sulfur (4–14). The monothiocarbonate li-

gands again give first-order spectra when expected, with

chemical shifts comparable to those of the corresponding salts.

The chemical shifts of hydrogen atoms on the carbon atom

attached to oxygen (i.e., OCH/OCH₂/OCH₃) are similar for a

given monothiocarbonate regardless of the number of phenyl

groups attached to germanium, as was observed for the corre-

sponding OCH_ngroups in analogous dithiocarbonates and

SCH_ngroups in trithiocarbonates. The chemical shifts in the

O-linked monothiocarbonates lie between those of the O-

linked dithiocarbonates and the S-linked trithiocarbonates,

suggesting that the electronegativity of the SCO₂group lies

between those of S₂CO and S₂CS. In Me₃Ge[SCO₂R] species

2−

metric stretch in CS₃(28), while the asymmetric stretch in

CS₃^2–is typically seen in the range of 900–950 cm^–1, which is

bracketed by the positions of ν(S₂CSC)_b, and ν(S₂CSC)_c. The

asymmetric and symmetric Ge–C stretches are seen at ca. 626

and 580 cm^–1in all Me₂Ge[S₂CSR]₂, 1–4, these values being

similar to those in Me₂GeCl₂. The similarity of the position

and separation between the modes indicates that 1–4 should

have C-Ge-C angles as wide as that of 121(4)° in Me₂GeCl₂

(29). Table

6 confirms that the C-Ge-C angle in

Me₂Ge[S₂CSEt]₂is 128.8(6)°.

The Ge–Cl stretching vibration, ν(Ge–Cl), is close to 282

cm^–1in all Ph₂GeCl[S₂CSR], 5–8, compared to an average of

ca. 400 cm^–1in Ph₂GeCl₂. A similar shift was noted for

Table 17. Selected features and their assignments in the vibrational spectra of compounds Ph₂GeCl[S₂CSR] 5–8 and Ph₂GeBr[S₂CSR], 9–12, where R = Et, i-Pr, n-Pr, and n-Bu.^a–d

10 11 12

[Raman] [Raman] [Raman] Assignment

1583 w [1583 (30)] 1585 w [1583 (35)] 15803 w [1586 (30)] 1583 w [1584 (20)] l-Phenyl

1434 s 1434 vs 1434 m 1434 s

n-Phenyl^d

1184 w [1187 (5)] 1184 mw [1187 (5)] 1184 w [1185 (5)] 1183 w [1184 (5)] a-Phenyl

1159 w [1155 (5)] 1158 vw [1159 (5)] 1158 m [1158 (5)] 1158 m [1158 (5)] 1154 vw [1150 (5)] 1160 w [1161 (5)] e-Phenyl

[1085 (5)] 1091 s [1084 (5)] 1090 m [1087 (10)] q-Phenyl^c

5

6

7

8

9

IR

1581 w [1585 (25)] 1583 w [1584 (25)] 1583 w [1583 (30)] 1583 w [n.o.]

1432 m 1433 vs 1433 m 1434 s

1183 m [1184 (10)] 1183 w [n.o.]

[Raman]

IR

[Raman]

IR

[Raman]

IR

[Raman]

IR

[Raman]

IR

1186 w [1187 (5)] 1184 ms [n.o.]

1158 w [1158 (5)] 1157 s [n.o.]

1088 s sh [1085 (5)] 1091 vs [1082 (5)] 1091 s [1084 (5)] 1090 m [1086 (10)] 1091 s [1085 (10)] 1092 s

1072 vs [n.o.]

1044 s sh [n.o.]

1070 vs [1070 (25)] 1058 s [1070 (10)] 1066 s sh [1070 (15)] 1067 m [1063 (5)] 1068 m [n.o.]

1039 vs [1041 (35)] 1043 s [1044 (10)] 1048 m [1048 (25)] 1050 m [n.o.] 1051 s [n.o.]

1063 m [n.o.]

1035 m [n.o.]

1060 m [1060 (5)] ν(S₂CSC)_a

1049 m [1045 (15)] ν(S₂CSC)_b

1031 s [1025 (10)] 1027 vs [1026 (20)] 1026 s [1025 (20)] 1026 m [1026 (20)] 1025 m [1025 (10)] 1026 m [1025 (10)] 1025 s [1027 (15)] 1026 m [1026 (20)] b-Phenyl

1004 m [998 (100)] 998 s [999 (100)] 998 m [998 (100)] 998 m [999 (100)] 998 s [998 (100)] 998 s

[998 (100)] 998 m [999 (100)] 998 m [998 (100)] p-Phenyl^c

849 s

737 vs

692 s

845 vs

736 vs

692 vs

840 s br

735 vs

693 vs

843 s br

735 vs

692 vs

820 s

734 s

691 s

821 s

734 s

692 s

819 m

735 s

691 s

819 m

734 s

691 s

ν(S₂CSC)_c^d

f-Phenyl^d

v-Phenyl^d

675 s sh [671 (10)] 669 mw [668 (60)] 679 s sh [669 (20)] 680 sh [670 (30)] 674 m [671 (15)] 674 m

[671 (15)] 674 w [673 (15)] 676 m [671 (10)] r-Phenyl^c

509 w

459 s

411 s

365 m

332 m

283 s

200 w

[517 (5)] 532 w [532 (25)] 512 w [512 (15)] 511 w

459 vs 458 w 458 w

414 m [429 (15)] 427 m [428 (8)] 414 m

[512 (25)] n.o.

457 s

[420 (5)] 400 w [n.o.]

[361 (10)] 318 m [n.o]

318 m

[517 (5)]

524 w

457 s

403 w

315 s

[n.o.]

509 w [n.o.]

457 s

405 w [n.o.]

319 m [n.o.]

319 m

508 w [501 (25)] ν(S₂CSC)_d

457 s

y-Phenyl^c,d

401 m [408 (5)] ν(Ge-S)

[n.o.]

[365 (45)] 363 s

335 s

[365 (50)] 367 m [377 (60)] 366 m

320 s [n.o.]

320 s

δ(S₂CSC)

t-Phenyl^c,d

335 m

336 m

[282 (10)] 282 m [282 (10)] 284 s

[286 (50)] 280 m

[n.o.]

225 w [224 (90)] 225 w[

224 (95)] 226 w [223 (85)] 226 w [225 (80)] ν(Ge-X)

[193 (20)] 191 w [198 (5] 195 m [198 (5)] ρ(S₂CSC)

[196 (35)] 200 w [196 (40)] 200 w [204 (80)] 200 m

[200 (5)] 190 m [193 (35)] 191 w

^aParentheses denote relative intensities in the Raman effect.

^bs = strong, m = medium, w = weak, sh = shoulder, br = broad, and v = very.

^cX-sensitive modes.

^dNo corresponding modes observed in the Raman effect.

330

Can. J. Chem. Vol. 76, 1998

Table 18. Selected features and their assignments in the vibrational spectra of 13–15.^a,b

Ph₃Ge[SCO₂Me], 13 Ph₃Ge[SCO₂(i-Pr)], 14 Ph₃Ge[SCO₂(n-Pr)], 15

IR

Raman

IR

Raman

IR

Raman

Assignment

1695 vs

n.o.

n.o.^c

1695 vs

n.o.

1700 (2)

1587(20)

n.o.

1025(10)

1001(100)

849 (1)

n.o.

1698 s

n.o.

1696 (5)

1587 (30)

1435 (1)

1184 (10)

1158 (12)

n.o.

1089 (3)

1026 (20)

1001 (100)

840 (1)

n.o.

ν(SCO₂C)_a

l-Phenyl

n-Phenyl

a-Phenyl

e-Phenyl

ν(SCO₂C)_b

ν(SC₂OC)_c

b-Phenyl

p-Phenyl

π(SCO₂)

1585 (30)

1429 (1)

1188 (7)

1158 (7)

n.o.

1428 s

1188 s

1158 s,sh

1140 s

1089 s

1023 m

996 m

815 ms

736 s

1428 s

1187 ms

1162 s

1148 s

1089 s

1023 m

998 m

848 s

1435 ms

1185 m,sh

1164 m,sh

1118 s

1090 s

1027 s

999 m

n.o.

1027 (8)

999 (100)

835 (2)

n.o.

830 ms

738 s

737 s

f-Phenyl

697 s

n.o.

697 s

n.o.

699 s

n.o.

v-Phenyl

675 m,sh

462 s

419 m

668 (8)

n.o.

428 (5)

675 m,sh

468 s

436 m

667 (10)

n.o.

430 (2)

675 m

463 s,br

424 m

668 (15)

n.o.

ν(SCO₂C)_d+ r-phenyl

y-Phenyl

ν(Ge-S)

^aParentheses denote relative intensities in the Raman effect.

^bs = strong, m = medium, sh = shoulder, br = broad.

^cNot observed.

Table 19. Selected features and their assignments in the vibrational spectra of 16–18.^a,b

Ph₂Ge[SCO₂Me]₂, 16 Ph₂Ge[SCO₂(i-Pr)]₂, 17 Ph₂Ge[SCO₂(n-Pr)]₂, 18

IR

Raman

n.o.^c

1584 (40)

n.o.

1187 (5)

n.o.

1027 (15)

999 (100)

843 (30)

n.o.

IR

Raman

IR

Raman

Assignment

1695 s

n.o.

1698 s

n.o.

1692 (8)

1585 (30)

n.o.

1170 (5)

n.o.

1090 (5)

1027 (20)

1000 (100)

846 (15)

n.o.

1702 s

n.o.^c

1700 (2)

1578 (30)

11432 (5)

n.o.

1156 (5)

1080 (4)

1026 (20)

996 (100)

843 (4)

n.o.

ν(SCO₂C)_a

l-Phenyl

n-Phenyl

a-Phenyl

ν(SCO₂C)_b

ν(SCO₂C)_c

b-Phenyl

p-Phenyl

π(SCO₂)

1427 s

1191 s

1134 s

1090 s

1025 s

998 m

817 s

1436 m

1170 s,sh

1159 s

1087 s

1025 ms

999 m

1434 s

1170 s

1132 vs

1095 s

1023 s,sh

1000 m,sh

833 m

737 s

843 ms

738 m

736 s

f-Phenyl

693 s

678 s,br

460 s

n.o.

678 (3)

n.o.

695 m,sh

673 m br

461 m

n.o.

672 (2)

n.o.

695 s

675 s

460 s

n.o.

670 (10)

n.o.

v-Phenyl

ν(SCO₂C)_d+ r-phenyl

y-Phenyl

434 ms

392 m

432 (2)

395 (1)

440 s

394 m

438 (15)

n.o.

427 m

390 s

427 (3)

392 (2)

ν(Ge-S)_asym

ν(Ge-S)_sym

^aParentheses denote relative intensities in the Raman effect.

^bs = strong, m =medium, sh = shoulder, br = broad.

^cNot observed.

Table 20. Selected features and their assignments in the vibrational spectra of 19–21.^a,b

Me₃Ge[SCO₂Me], 19 Me₃Ge[SCO₂(i-Pr)], 20 Me₃Ge[SCO₂(n-Pr)], 21

IR

Raman

IR

Raman

IR

Raman

Assignment

1694 vs

1145 vs

1067 s,sh

820 s,sh

676 s

627 s

587 s

441 s

1687 (5)

1145 (5)

1097 (5)

848 (10)

n.o.^c

611 (30)

569 (100)

437 (10)

1694 vs

1134 vs

1090 s

835 s

678 s

617 ms

575 s

1688 (5)

1140 (3)

1091 (2)

840 (5)

n.o.

612 (40)

570 (100)

437 (2)

1691 vs

1132 vs

1066 s,sh

832 s

675 s

613 s

1688 (2)

n.o.

1088 (3)

841 (5)

n.o.

610 (35)

569 (100)

421 (5)

ν(SCO₂C)_a

ν(SCO₂C)_b

ν(SCO₂C)_c

π(SCO₂)

ν(SCO₂C)_d

ν(Ge-C)_asym

570 ms

419 ms

ν(Ge-C)_sym

ν(Ge-S)

434 s

^aParentheses denote relative intensities in the Raman effect.

^bs = strong, m = medium, sh = shoulder, br = broad.

^cNot observed.

331

Drake and Yang

Me₂GeCl[S₂CNEt₂] where ν(Ge–Cl) was assigned at 293 cm^–1

(8). Similarly, ν(Ge–Br), is at ca. 224 cm^–1in all

Ph₂GeBr[S₂CSR], 9–12, compared to ca. 315 cm^–1Ph₂GeBr₂.

This weakening of the Ge—X bond by the trithiocarbonate

group may contribute to the difficulty of isolating the mixed

Me₂GeX[S₂CSR] species. A weak Ge—X bond, accompanied

by less stereochemical hindrance to an incoming group with

Me rather than Ph groups attached to germanium, could result

in partially substituted compounds acting as reactive interme-

diates that could also undergo rapid exchange to the bis sub-

stituted species and dihalodimethylgermane.

Fig. 1. ORTEP plots of the molecule Me₂Ge[S₂CSEt]₂(1)

illustrating (a) the tetrahedral environment about germanium, (b)

the pendant sulfur atoms acting as weak donors, and (c) the

planarity of all non-hydrogen atoms except the carbon atoms of the

ethyl groups. The atoms are drawn with 30% probability ellipsoids.

Hydrogen atoms omitted for clarity in (a) and (b).

(a)

C(7')

S(2)

C(7)

S(5)

C(5)

C(2)

C(6)

Ge(1)

C(1)

C(4)

Distinctive features in the infrared and Raman spectra and

their assignments are given for Ph₃Ge[SCO₂R], 13–15,

Ph₂Ge[SCO₂R]₂, 16–18, and Me₃Ge[SCO₂R], 19–21, in Ta-

bles 18–20. The assignments are based on the same factors

described for the trithiocarbonates along with trends involving

related dithiocarbonate species. A strong band attributable to

the CTO stretching vibration, ν(CTO), which is observed at

ca. 1620 cm^–1in the NaSCO₂R salts, is shifted to higher wave

number (1690–1703 cm^–1) in all nine compounds. This sup-

ports the presence of an essentially monodentate monothiocar-

bonate ligand with a very strong terminal CTO bond. The O

atoms of the SCO₂C group should give rise to two intense

peaks in the infrared spectra, in addition to the one at

1690–1703 cm^–1, and two such peaks, which are presumably

primarily attributable to ν(SC–O) and ν(SCO–C), are seen in

the region 1188–1066 cm^–1for 13–21, designated ν(SCO₂C)_b

and ν(SCO₂C)_c, respectively. These assignments are entirely

consistent with the X-ray structures of compounds 13, 14, and

16. Two distinctive strong peaks are also seen at ca. 840 and

670 cm^–1. The former can be assigned to the out-of-plane bend,

π(SCO₂), which is assigned at 830–873 cm^–1for π(CO₃) in

carbonate salts, suggesting similar π-electron delocalization in

these planar groups. The fourth stretching vibration,

ν(SCO₂C)_d, presumably primarily ν(GeS–C), is assigned to

670–678 cm^–1, which is similar to general assignments of

C—S single bonds and to the assignments reported for the

corresponding dithiocarbonates.

C(3)

S(4)

S(1)

S(6)

S(3)

C(7')

(b)

S(2)

S(5)

C(2)

Ge(1)

C(5)

S(6)

C(3)

(c)

C(1)

S(3)

H(4)

C(4)

S(1)

S4

C(7)

C(6)

C(7')

H(5)

H(2)

H(1')

C(2)

S(5)

S(6)

S(2)

S(4)

Ge(1)

C(6)

H(6)

C(3)

H(3)

H(2')

S(3)

C(1)

C(7)

H(7)

S(1)

C(5)

C(4)

H(1)

H(9)

H(8)

being similar to those in Ph₂Ge[S₂CS(i-Pr)]₂, Ph₂Ge[S₂CO(i-

Pr)]₂(12), Me₂Ge[S₂CNMe₂]₂(6), Me₂GeCl[S₂CNMe₂] (5),

and even in Ph₃GeSC₆H₄(t-Bu) (31).

The Ge–S vibrational modes are readily assigned within

440–400 cm^–1for 13–21 in similar positions to those in the

dithiocarbamates (4–6) and Me₃GeSR (30), but at slightly

higher wave number compared to those of the trithiocarbon-

ates. This is consistent with the greater tendency for the trithio-

carbonates to form anisobidentate links leading to slightly

weaker Ge—S primary bonds. The Ge—S bond lengths in 13,

14, and 16 are slightly shorter than those of Me₂Ge[S₂CSEt]₂,

1, and Ph₂Ge[S₂CS(i-Pr)]₂.

The closing down of the S-Ge-S angles to 90.0(1)° in 1 is

similar to that observed in the dithiocarbamate analogues,

Ph₂Ge[S₂CNEt₂]₂and Me₂Ge[S₂CNMe₂]₂, where the S-Ge-S

angles are 84.4(1)° and 87.0(1)°, respectively. These smaller

angles are associated with the fact that a terminal sulfur (CTS)

atom is oriented toward the germanium center (see Fig. 1) at

Ge—S distances of 3.051(5) and 3.246(5)

Me₂Ge[S₂CSEt]₂, 3.078(2) and 3.158(2)

Me₂Ge[S₂CNMe₂]₂, 3.224(5) and 3.304(5)

Å

for

Ph₂Ge[S₂CS(i-Pr)]₂, and 3.183(1) Å for Ph₂Ge[S₂CNEt₂]₂. By

contrast, in the analogous dithiocarbonate, Ph₂Ge[S₂CO(i-

Pr)]₂, where the terminal sulfur atom is oriented away from the

germanium center (with Ge—S = 4.753(4) Å), the S-Ge-S an-

gle is much larger at 103.2(1)° (12). Whether distances in the

range of 3.05–3.3 Å, which are considerably less than the sum

of the van der Waals radii of 3.75 Å, are sufficiently short to

be considered as partial bonds may be questioned, but there is

a relationship between these Ge—S nonbonding or aniso-

bonding distances and the closing down of the S-Ge-S angle

from the regular tetrahedral angle when the sulfur atom is ori-

ented toward, rather than away from, germanium.

The crystal structure of Me₂Ge[S₂CSEt]₂, 1

Dimethylbis(S-ethyl trithiocarbonato)germane, 1, crystallizes

in the space group P2₁/m. The ORTEP diagram in Fig. 1(a)

illustrates, along with Table 6, that the immediate environment

about germanium is that of a distorted tetrahedron. The S-Ge-C

angles have an average value of 108.8(10)° compared with

111.8(17)° for Ph₂Ge[S₂CS(i-Pr)]₂(15). By contrast, the C-

Ge-C angles are very much larger than the regular tetrahedral

angle: 128.8(6)° in

1 compared with 118.1(3)° in

Ph₂Ge[S₂CS(i-Pr)]₂. This opening up of the C-Ge-C angle in

Me₂Ge[S₂CSEt]₂was predicted from its vibrational spectrum.

The average Ge—C bond length of 1.93(1) Å is typical for

R₂GeL₂or R₃GeL species, where L is a sulfur-bonding moiety,

The average Ge—S bond length (2.295(1) Å) in 1 is longer

than in the analogous dithiocarbonate, Ph₂Ge[S₂CO(i-Pr)]₂

332

Can. J. Chem. Vol. 76, 1998

Fig. 2. ORTEP plot of the molecule Ph₃Ge[SCO₂Me] (13). The

atoms are drawn with 30% probability ellipsoids. Hydrogen atoms

omitted for clarity.

(2.252(3) Å) in which there are no Ge—S secondary interac-

tions (15). However, it is similar to those in Ph₂Ge[S₂CNEt₂]₂,

Me₂Ge[S₂CNMe₂]₂, and other germanium dithiocarbamates

where there is the same probability of the presence of secon-

dary bonding (6, 14). In view of the similarities noted in the

spectra of the trithiocarbonates, all of these S-alkyl trithiocar-

bonate derivatives probably have the same weak anisobiden-

tate bonding as indicated by the molecular structures of

Me₂Ge[S₂CSEt]₂, 1, and Ph₂Ge[S₂CS(i-Pr)]₂(15). The CTS

bonds in 1, which average 1.63(8) Å, are very slightly longer

than those in Ph₂Ge[S₂CO(i-Pr)]₂, 1.61(1) Å, which is again

consistent with the presence of weak secondary interactions

leading to the orientation of the terminal CTS rather than the

CSR moiety toward the germanium centre. The average bite

angle of 62.4(7)° in Ph₂Ge[S₂CS(i-Pr)]₂is essentially the same

as that in Ph₂Ge[S₂CNEt₂]₂, where anisobidentate linkages ap-

pear to give a better overall description of the bonding of

dithiocarbamates to germanium (14). There is an even larger

bite angle of 65.8(1)° in 1, which suggests an even stronger

anisobidentate bond as implied by the inclusion of

Ge(1)—S(2) and Ge(1)—S(4) bonds in Fig. 1(b).

The S—CR bonds in the trithiocarbonate groups at 1.82(2)

Å are essentially as expected from the sum of the covalent radii

of S and C, whereas the average length of C—SGe and C—SR

bonds is 1.74(2) Å, and that of the “terminal” CTS bond is

1.63(1) Å, indicating that π-electron density delocalization is

not significantly extended beyond the planar groups. Never-

theless, all of the non-hydrogen atoms in both trithiocarbonate

groups are coplanar, as required by the mirror plane, and the

relationship between the groups is well illustrated by Fig. 1(c).

C(3)

O(1)

C(9)

C(2)

Ge(1)

C(1)

O(2)

S(1)

C(15)

1.950(9) Å in 13 and 1.93(1) to 1.94(1) Å in 14, are comparable

with those found in the analogous trithiocarbonates and related

species as described above, and cover the same range as in the

dithiophosphate, Ph₃Ge[S₂P(OMe)₂], 1.930(5)–1.950(5) Å.

The Ge—S bond length of 2.254(3) D in both 13 and 14 is

bracketed by those reported for the dithiocarbonates,

Ph₃Ge[S₂COMe] (2.249(4) D) and Ph₃Ge[S₂CO(i-Pr)]

(2.272(2) D), and slightly shorter than in the dithiophosphate,

Ph₃Ge[S₂P(OMe)₂] (2.285(1) Å).

As expected, the terminal CTO bond lengths of 1.19(1) and

1.20(5) D in 13 and 14, respectively, are much shorter than the

other C—O bonds. They are also close to the expected value

for a CTO double bond. The SC—O bonds, in turn, are sig-

nificantly shorter than the SCO—C bonds, being similar to

those reported for the two analogous dithiocarbonates (avg.

1.34(1) and 1.45(1) Å, respectively), which is consistent with

the π-bond character not extending significantly beyond the

planar SCO₂core.

The crystal structures of Ph₃Ge[SCO₂Me], 13,

Ph₃Ge[SCO₂(i-Pr)].0.5CH₂Cl₂, 14, and

Ph₂Ge[SCO₂Me]₂, 16

Triphenyl(O-methyl monothiocarbonato)germane, 13, and

triphenyl(O-isopropyl monothio-carbonato)germane, 14, both

−

crystallize in the space group P1 (No. 2), the latter with dichlo-

romethane in the lattice. The ORTEP diagrams in Figs. 2 and

3 illustrate, along with Tables 7 and 8, that the immediate en-

vironment about germanium in both molecules is that of a

distorted tetrahedron. The average values of the C-Ge-C angles

are 110.8(4)° in 13 and 111.6(16)° for the two independent

molecules in 14, while those of the S-Ge-C angles are 108(6)°

in 13 and 107(5)° in 14. It is immediately obvious that the

variation in the S-Ge-C angles is larger than for the C-Ge-C

angle, which arises because one S-Ge-C angle is considerably

smaller (100.4(3)° in 13 and 99.4(3)° in 14) than the other two

(111.8(15)° in 13 and 110.7(27)° in 14). All of these values are

close to those found for the analogous dithiocarbonates,

Ph₃Ge[S₂COMe] and Ph₃Ge[S₂CO(i-Pr)]. The similarity ex-

tends to dithiophospates, such as Ph₃Ge[S₂P(OMe)₂], where

one S-Ge-C angle is again significantly smaller than the other

two (4). In the dithiocarbonates and dithiophosphates, an alk-

oxy group is oriented towards germanium in preference to a

terminal sulfur atom, whereas in 13 and 14 the alkoxy group is

oriented away from germanium and the terminal oxygen atom

toward germanium. Possibly, the slightly smaller range in the

S-Ge-C angles in the monothiocarbonates reflects the fact that

the less bulky terminal oxygen atom is more readily accommo-

dated.

The terminal O atom is oriented towards germanium, with

the Ge—O distance being 3.112(7) and 3.12(2) Å in 13 and

14, respectively, which is similar to the Ge—S distances in

trithiocarbonates. Thus, the intramolecular interactions, if any,

must be extremely weak. However, as mentioned above, the

orientations of the ligand in the dithiocarbonates and

Ph₃Ge[S₂P(OMe)₂] are both such as to place the (OR) groups,

rather than the terminal sulfur atoms, closer to the germanium

center and the Ge—OR distances in Ph₃Ge[S₂COMe] (2.98(2)

Å) and Ph₃Ge[S₂CO(i-Pr)] (3.115(4) D), are similar to the

Ge—O(terminal) distances in 13 and 14.

Diphenylbis(O-methyl monothiocarbonato)germane, Ph₂Ge-

[SCO₂Me]₂, 16, crystallizes in the space group Cc (No. 9). The

ORTEP diagram (Fig. 4) and Table 9 confirm that the imme-

diate environment about germanium is again the expected dis-

torted tetrahedron. The S-Ge-S angle of 93.3(7)° and C-Ge-C

angle of 117.85(7)° are very close to those in the analogous

dithiocarbonates, Ph₂Ge[S₂COMe]₂, where the corresponding

angles are 93.4(2)° and 117.1(3)°) (11). The distortion from

the regular tetrahedral angle is greater than was found for

Ph₂Ge[S₂CO(i-Pr)]₂(12), where the corresponding angles are

103.2(1)° and 115.6(3)°, but less than that found for the trithio-

carbonate, Ph₂Ge[S₂CS(i-Pr)]₂, described earlier (15), where

the corresponding angles are 87.3(2)° and 118.1(3)° respec-

The Ge—C distances, which range from 1.931(9) to

333

Drake and Yang

Fig. 3. ORTEP plot of the molecule Ph₃Ge[SCO₂(i-Pr)] (14)

showing both molecules in the asymmetric unit as well as the

CH₂Cl₂trapped in the lattice. The atoms are drawn with 30%

probability ellipsoids. Hydrogen atoms omitted for clarity except

for those in dichloromethane.

Fig. 4. ORTEP plots of the molecule Ph₂Ge[SCO₂Me]₂(16)

showing different views of the two molecules in the asymmetric

unit. The atoms are drawn with 30% probability ellipsoids.

Hydrogen atoms omitted for clarity except for those in

dichloromethane.

C(22)

C(16)

C(28)

C(27)

S(3)

C(32)

C(17)

S(1)

Ge(1)

C(20)

O(8)

O(5)

S(4)

C(19)

O(2)

C(1)

C(18)

C(12)

C(4)

C(10)

Ge(2)

C(21)

O(1)

C(5)

C(38)

O(7)

C(17)

C(26)

C(2)

O(6)

C(33)

Ge(2)

C(3)

S(2)

O(4)

C(39)

C(40)

C(22)

C(23)

C(25)

C(27)

C(26)

C(45)

C(32)

O(3)

Cl(1)

C(28)

C(24)

Cl(2)

C(11)

C(5)

O(3)

O(1)

C(4)

tively, or Me₂Ge[S₂CSEt]₂, 1, with angles of 90.0(1)° and

128.6(6)°, respectively. The S-Ge-S angle in 16 is consider-

ably wider than the 84.4° in Ph₂Ge[S₂CNEt₂]₂(8), where the

ligand was assumed to be anisobidentate.

C(3)

C(2)

Ge(1)

S(1)

C1

O(4)

The Ge—C bond length of 1.928(5) D in 16 is again very

similar to those reported for 13 and 14, as well for trithiocar-

bonates including 1, and the other S-linked groups mentioned

earlier. The average Ge—S bond length in 16 of 2.258(4) D

brackets those observed in Ph₂Ge[S₂COMe]₂(2.262(3) D) and

Ph₂Ge[S₂CO(i-Pr)]₂(2.252(1) D) and is slightly shorter than

those found for the dithiocarbamate, Ph₂Ge[S₂CNEt₂]₂

(2.277(2) D) and the trithiocarbonate, Ph₂Ge[S₂CS(i-Pr)]₂

(2.280(5) D). In general, the bis compounds appear to have

slightly longer Ge—S bonds than those containing only one

thio ligand as in 13 and 14.

The GeS—C average bond length in 16 of 1.77(1) D is not

significantly different from those in 13 and 14, and is typical

of values observed in Ph₂Ge[S₂COMe]₂, Ph₂Ge[S₂CO(i-Pr)]₂,

and Ph₂Ge[S₂CNEt₂]₂(1.76(1) D), as well as for

Ph₂Ge[S₂CS(i-Pr)]₂(1.745(6) D). The distances between ger-

manium and the terminal O atom of 3.00(1) and 3.07(1) Å are

similar to those in 13 and 14, as are the S-Ge—O bite angles,

which range from 57.3(3)° to 62.9(1)°, again indicating that if

there is any secondary interaction between germanium and the

terminal O atom, it must be very weak. The bond lengths and

angles within the SCO₂C group of 16 are essentially the same

as in 13 and 14. The angles in the planar core do indeed add

up to 360°, with average values in 16 being OTC-S

(125.8(13)°), OTC-O (125.8(17)°), and S-C-O (108.5(13)°)

compared with OTC-S (125.0(14)°), OTC-O (125.7(6)°, and

S-C-O (109.3(16)° for 13 and 14. The much larger angles

O(2)

S(2)

involving the terminal CTO bond reflect the fact that this is

the bond most strongly involved in the delocalized π-bonding.

The average value of the C-O-C angle in all three molecules

is 116(1)°, which is consistent with much less π-bond character

in C—O bonds involved in the C-O-C link than in the SCO₂

core. The Ge-S-C angles, which ranged from 96.5(7)° to

100.5(6)°, are somewhat smaller, but essentially very similar

to the corresponding angles in Ph₂Ge[S₂COMe]₂, 102.7(5)°,

Ph₂Ge[S₂CO(i-Pr)]₂, 105.0(3)°, Ph₂Ge[S₂CNEt₂]₂, 102.1(1)°,

as well as in Ph₂Ge[S₂CS(i-Pr)]₂, 101(1)°, indicating little or

no change in the nature of this link regardless of the thio de-

rivative attached.

Concluding comments

Previous studies of organogermanium dithiocarbonates gave a

wide variety of relatively stable derivatives, some of which

were tested for suitability as oil additives. Given the paucity of

work on any main group monothiocarbonates, it is somewhat

surprising that organogermanium monothiocarbonates have

proven to be relatively easy to prepare and characterize fully

by spectroscopic methods as well as by X-ray crystallography.

However, the organogermanium trithiocarbonates all readily

334

Can. J. Chem. Vol. 76, 1998

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eliminate CS₂regardless of the nature of the organo groups or

the number of groups attached to germanium. By contrast, the

only sign of reductive elimination in the monothiocarbonates

is the presence of the COS⁺ion in some of their mass spectra.

The interpretation of the NMR and vibrational spectra is en-

tirely consistent, with the structures found in the solid state

being essentially maintained in solution. Thus, like the dithio-

carbonates, there is an essentially monodentate link through

sulfur. However, in all cases in the solid state, there is appar-

ently a weak interaction with the “terminal” sulfur atom (for

tri- and dithiocarbonates) and possibly even with the “termi-

nal” oxygen atom (for monothiocarbonates) as these atoms are

oriented toward the germanium center at distances well inside

that of the sum of the van der Waals radii, particularly for

Ge—S. In related tellurium species, we found that on occa-

sion, as in Ph₂Te[SCO₂(i-Pr)]₂, one of the OR groups was ori-

ented toward tellurium and the pendant oxygen was possibly

involved in a weak link to an adjacent tellurium center, creat-

ing a weakly bonded extended structure. There was no indica-

tion of similar behavior with germanium.

Acknowledgement

We wish to thank the Natural Sciences and Engineering Re-

search Council of Canada for financial support.

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Article Doi

Synthesis, spectroscopic characterization, and structural studies of organogermanium tri- and monothiocarbonates. Crystal structures of Me2Ge[S2CSEt]2, Ph3Ge[SCO2Me], Ph3Ge[SCO2(i-Pr)], and Ph2Ge[SCO2Me]2

DOI: 10.1139/v98-026

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