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Dimethyltellurium alkylene dithiophosphates of the type [Formula: see text] where G = —CMe2CMe2—, —CHMeCHMe—, —CH2CMe2CH2—, and —CH2CEt2CH2—, have been synthesized in 80–90% yields by reaction of the corresponding sodium or ammonium salts of the appropriate dithiophosphoric acids with dimethyltellurium dichloride in toluene. Me2Te[S2P(OPh)2]2 was also prepared in a similar fashion. The compounds have been characterised by elemental analyses and 1H, 13C, 31P, and 125Te NMR, infrared and Raman spectroscopy. The crystal structures of [Formula: see text] and [Formula: see text] were determined. [Formula: see text]1, crystallizes in space group P21/c (No. 14) with the cell parameters a = 12.707(3) Å, b = 11.482(2) Å, c = 16.782(2) Å, β = 98.00(1)°, V = 2424(1) Å3, Z = 4, R = 0.0399, Rw = 0.0343. [Formula: see text]4, crystallizes in space group [Formula: see text] (No. 2) with the cell parameters a = 12.580(3) Å, b = 13.313(3) Å, c = 8.206(1) Å, α = 91.28(2)°, β = 104.94(2)°, γ = 78.52(2)°, V = 1301(1) Å3, Z = 2, R = 0.0364, Rw = 0.0295. The immediate environment about tellurium in both molecules is that of the saw-horse structure typical of tellurium(IV) compounds with the two methyl groups equatorial and one sulfur atom from each dithiophosphate group occupying the axial positions. The consideration of the second sulfur atom as part of the coordinating sphere is discussed in terms of a modification of Pauling's approach to partial bond orders. The 1H NMR spectra suggest that these dithiophosphates may be fluxional in solution and/or that there is rapid exchange of the sulfur atoms.

The S-alkyl trithiocarbonate (trixanthate) derivatives Me 3 Ge[S 2 CSR], Ph 3 Ge[S 2 CSR], and Ph 2 Ge[S 2 CSR] 2 , where R=Et, i-Pr, n-Pr, and n-Bu, have been prepared in 73-85% yields by the reaction of the potassium salt of the appropriate trithiocarbonic (trixanthic) acid with iodotrimethylgermane, bromotriphenylgermane, or dichlorodiphenylgermane. The compounds were characterized by infrared, Raman, and 1 H and 13 C NMR spectroscopy. The crystal structure of Ph 2 Ge(S 2 CS(i-Pr)] 2 was determined, and it crystallizes in space group P1 (No. 2) with the cell parameters a=10.752(9) A, b=13.36(1) A, c=9.64(2) A, α=105.8(1) o , β=113.2(1) o , γ=91.79(9) o , V=1211(3) A 3 , and Z=2; R=0.0638, and R w =0.0626

The earth's future climate state is highly dependent upon changes in terrestrial C storage in response to rising concentrations of atmospheric CO₂. Here we show that consistently enhanced rates of net primary production (NPP) are sustained by a C-cascade through the root-microbe-soil system; increases in the flux of C belowground under elevated CO₂ stimulated microbial activity, accelerated the rate of soil organic matter decomposition and stimulated tree uptake of N bound to this SOM. This process set into motion a positive feedback maintaining greater C gain under elevated CO₂ as a result of increases in canopy N content and higher photosynthetic N-use efficiency. The ecosystem-level consequence of the enhanced requirement for N and the exchange of plant C for N belowground is the dominance of C storage in tree biomass but the preclusion of a large C sink in the soil.

The O-alkyl dithiocarbonate (xanthate) derivatives MeGe[S2COMe]3, MeGe[S2COEt]3, MeGe[S2CO(i-Pr)]3, t-BuGe[S2COEt]3, t-BuGe[S2CO(i-Pr)]3, n-Bu3Ge[S2COEt] and n-Bu3Ge[S2CO(i-Pr)] have been prepared in 64–70% yields by reaction of the sodium or potassium salt of the dithiocarbonic (xanthic) acid with trichloromethyl-, t-butyltrichloro- or tri-n-butylchlorogermane. The compounds were characterized by elemental analysis and infrared, Raman and 1H and 13C NMR spectroscopy. The molecular structures of MeGe[S2COEt]3 and MeGe[S2CO(i- Pr)]3 were determined and CS2 was found in the crystal lattices. MeGe[S2COEt]3·0.37CS2(2), which crystallizes as monoclinic in space group P21/c (No. 14), has the cell parameters a = 12.253(8), b = 7.520(4), c = 24.32(1) A, β = 103.74(4)°, V = 2177(2) A3, Z = 4, R = 0.0667, Rw = 0.0632. MeGe[S2CO(i-Pr)]3·0.50CS2 (3), which crystallizes as triclinic in space group P1 1 (No. 2), has the cell parameters a = 14.81(1), b = 14.82(1), c = 14.04(1) A, α = 93.01(7), β = 114.19(5), γ = 60.09(4)°, V = 2392(7) A3, Z = 4, R = 0.0662, Rw = 0.0672. In both compounds, the immediate environment about germanium is very similar corresponding to a distorted tetrahedron in which the three monodentate dithiocarbonates subtend very similar angles so that the average of the three SGeC angles is 115.9(2)° in 2 and 115.9(3)° in 3 and the average of the SGeS angles is 102.3(2)° in both 2 and 3. The GeC bond is 1.92(2) A in 2 and 1.91(1) and 1.92(1) A in the two independent molecules in 3, and the GeS bonds average to 2.249(1) A in 2 and 2.249(3) A in 3. All of the dithiocarbonate groups are oriented in an identical fashion so that the average Ge···O distance is 2.93(1) in 2 and 2.916(6) A in 3, with the non-bonded sulfur atoms turned away from the germanium center.

[PtCl{(C 10 H 13 OTe) 2 NH}]Cl.CHCl 3 .H 2 O, M r =972.2, triclinic, P1, a=10.590 (7), b=17.606 (6), c=8.493 (3) A, α=90.10 (3), β=102.22 (5), γ=106.85 (4) o , V=1478 (3) A 3 , Z=2, D m =2.20, D x =2.18 Mg m -3 , λ(Mo Kα)=0.71069 A, μ=7.218 mm -1 , F(000)=908, T=297 (1) K, final R=0.0429, wR=0.0446 for 2910 unique observed reflections, S=1.38

The compounds Me2Te[S2CNR2]2, Me2TeCl[S2CNR2], (p-MeOC6H4)2Te[S2CNR2]2, and (p-MeOC6H4)2TeCl[S2CNR2], where R = Me, Et, have been prepared and characterised primarily by vibrational and NMR spectroscopy. Variable temperature NMR spectroscopy and qualitative time studies indicate that in solution the dimethoxyphenyltellurium derivatives undergo the reductive-elimination noted for analogous phenyl derivatives but the reductive-elimination does not occur with the dimethyl tellurium derivatives. The crystal structures of Me2Te[S2CNMe2]2, 1, and (p-MeOC6H4)2-Te[S2CNMe2]2, 5, were completed. The cell parameters for 1, which crystallizes as monoclinic in space group P21/n, are a = 13.550(2), b = 13.034(2), c = 17.854(2) Å, β = 106.61(1)°, V = 3021.6(7) Å3, Z = 8, R = 0.0368, and Rw = 0.0402 and for 5, which crystallizes as monoclinic in space group C2/c, are a = 35.36(1), b = 11.063(3), c = 12.778(3) Å, β = 96.16(3)°, V = 4963(3) Å3, Z = 8, R = 0.0627, and Rw = 0.0646.

The reaction of N-(2-chloroethyl)benzamide and N-[3-bromopropyl]phthalimide with ArTe- Na+ generated in situ by borohydride reduction of Ar2Te 2, has resulted in N-[2-(4-methoxyphenyltelluro)ethyl] benzamide (L1) and N-[2-(4-methoxyphenyl telluro)propyl] phthalimide (L2) respectively, which are potentially (Te, N)-type ligands. Their NMR (1H and 13C) spectra are characteristic and single crystal structures are solved. The Te-C(alkyl) distance [2.140(8)/2.151(4) Å] is longer than Te-C(aryl) distance [2.107(8)/2.128(5) Å].

The reaction of N-(2-chloroethyl)benzamide and N-[3-bromopropyl]phthalimide with ArTe- Na+ generated in situ by borohydride reduction of Ar2Te2, has resulted in N-[2-(4-methoxyphenyltelluro)ethyl] benzamide (L-1) and N-[2-(4-methoxyphenyl telluro)propyl] phthalimide (L-2) respectively, which are potentially (Te, N)-type ligands. Their NMR (H-1 and C-13) spectra are characteristic and single crystal structures are solved. The Te-C(alkyl) distance [2.140(8)/2.151(4) Angstrom] is longer than Te-C(aryl) distance [2.107(8)/2.128(5)A].

The review is focused on the (XPR 2 )(YPR′ 2 )NH acids (X, Y=O, S, Se; R, R′=alkyl, aryl, OR) and their main group metal derivatives. The methods of preparation, spectroscopic studies and molecular structures of known imidodiphosphorus acids and related derivatives as well as those of inorganic and organometallic main group metal complexes containing either protonated or deprotonated imidodiphosphorus ligand moieties are systematized and discussed.

The tetrakis(O-alkyl dithiocarbonato)germanium derivatives Ge[S 2 COMe] 4 , Ge[S 2 COEt] 4 , and Ge[S 2 CO(i-Pr)] 4 have been prepared in 55-65% yields by reaction of the sodium salt of the dithiocarbonic (xanthic) acid with tetrachlorogermane. The compounds were characterized by infrared, Raman, and 1 H and 13 C NMR spectroscopy.

The series Ph2TeBr[S2CNR2], where R = Bu, Pr, i-Pr, Et, and Me, as well as Ph2TeCl[S2CNR2] and Ph2Te[S2CNR2]2, where R=Bu, Pr, have been synthesized and characterized by elemental analysis and vibrational spectroscopy. Comparisons of the effect of changing R groups and halogen atoms can be made based on the two crystal structures determined herein along with earlier work. The geometry about tellurium is consistent with that of a distorted sawhorse structure where the dithiocarbamate groups are monodentate (or anisobidentate). The crystal structures of Ph2TeBr[S2CNEt2], 4, and Ph2Te[S2CNBu2]2, 7, were completed. The cell parameters for 4 are a = 11.204(3) Å, b = 14.106(11) Å, c = 13.867(10) Å, α = 99.62(6)°, β = 102.76(5)°, γ = 87.73(4)°, V = 2107 Å3, Z = 4, R = 0.0448, and Rw = 0.0489 and for 7 are a = 19.392(6) Å, b = 9.622(2) Å, c = 19.089(6) Å, β = 104.70(2)°, V = 3445(2) Å3, Z = 4, R = 0.0397, and Rw = 0.0439. Nuclear magnetic resonance spectra are not simple and indicate that several species are present in solution, as rearrangements and reductive elimination take place. Key words: structure, tellurium, bromo, diphenyl, dialkyldithiocarbamato.

The O-alkyl dithiocarbonate (xanthate) derivatives PhGe[S 2 CO(i-Pr)] 3 , Ph 2 Ge[S 2 CO(i-Pr)] 2 , Ph 3 Ge[S 2 CO(i-Pr)], Ph 3 Ge-[S 2 COMe], Ph 3 Ge[S 2 COEt], Ph 3 Ge[S 2 CO(n-Bu)], Ph 2 Ge[S 2 CO(n-Bu)] 2 , and possibly PhGe[S 2 COR] 3 , where R=Me, and Et, have been prepared in 60-86% yields by reaction of the sodium or potassium salt of the dithiocarbonic (xanthic) acid with trichlorophenyl-, dichlorodiphenyl- or chlorotriphenylgermane. The compounds were characterized by elemental analysis and infrared, Raman and 1 H and 13 C NMR spectroscopy

Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, N9B 3P4, Canada Department of Chemistry, University of Southampton, Highfield, Southampton, SO 17 1 BJ, UK Department of Pure and Applied Chemistry, M. D. S. University, Ajmer-305 009, Rajasthan, India E-mail : ratnaniraju@rediffmail.com Manuscript received 10 March 2008, accepted 4 June 2008 A new series of bromodioxomolybdenum(VI) complexes, MoO2Br(S2CNR2)(OPPh3) (NR2 = NEt2, N(i-Pr)2, NCH2(CH2)3CH2) and MoO2Br(S2COR)(OPPh3) (R = Et, n-Pr, i-Pr) were prepared by the reaction of dibromodioxobis(triphenylphosphineoxide)molybdenum(VI) with sodium/potassium salts of the corresponding dithiocarbamates or dithiocarbonates in 1 : 1molar ratio in dichloromethane. These newly synthesized complexes were characterized on the basis of elements analysis and spectral (IR and 1H NMR) studies. The crystal structure of 2,5- dimethylpyridium bromide is also described. [CMeCHCHCMeCHNH]Br crystallizes as monoclinic in the space group P21/c with cell parameters a = 8.6591(9), b = 13.252(1), c = 7.258(1) Å, β = 101.94(1) 0 , V = 814.9(2) Å3, Z = 4, R = 0.0393, Rw = 0.0885.

Forest ecosystems release large amounts of carbon to the atmosphere from fine-root respiration (R(r)), but the control of this flux and its temperature sensitivity (Q(10)) are poorly understood. We attempted to: (1) identify the factors limiting this flux using additions of glucose and an electron transport uncoupler (carbonyl cyanide m-chlorophenylhydrazone); and (2) improve yearly estimates of R(r) by directly measuring its Q(10)in situ using temperature-controlled cuvettes buried around intact, attached roots. The proximal limits of R(r) of loblolly pine (Pinus taeda L.) trees exposed to free-air CO(2) enrichment (FACE) and N fertilization were seasonally variable; enzyme capacity limited R(r) in the winter, and a combination of substrate supply and adenylate availability limited R(r) in summer months. The limiting factors of R(r) were not affected by elevated CO(2) or N fertilization. Elevated CO(2 )increased annual stand-level R(r) by 34% whereas the combination of elevated CO(2) and N fertilization reduced R(r) by 40%. Measurements of in situ R(r) with high temporal resolution detected diel patterns that were correlated with canopy photosynthesis with a lag of 1 d or less as measured by eddy covariance, indicating a dynamic link between canopy photosynthesis and root respiration. These results suggest that R(r) is coupled to daily canopy photosynthesis and increases with carbon allocation below ground.

Formula chem.A very efficient synthesis of (2R,3S) and (25,3R)-4-aminobutane-1,2,3-triol has been developed using either D- or L-glucose as the starting material. A key step is the one-pot conversion of an aldehyde to an amide, the scope of which has been extended to include other carbohydrate-derived aldehydes.

The reactions of β‐lapachone (1) with 1,2‐diaminoethane (2) and 1,2‐diaminopropane (4) gave the tetracyclic pyrazine derivatives (3) and mixtures of (5) and (6), respectively, while reaction with o‐phenylene diamine (7) gave the quinoxaline derivative (8). The structure of pyrazine derivative (3) is confirmed by single‐crystal X‐ray diffraction study.

The reaction between 2-aminobenzenethiol and ethyl acetoacetate is studied under a variety of conditions, and a procedure for the exclusive synthesis of 1,4-benzothiazines by the neat reaction of substituted aminothiols with beta-ketoesters and beta-dicarbonyl compounds in 85-96% yield is described. With microwave heating, even when both the reactants are solid, yields are high, reaction times brief, and work-up easy. A facile reaction is also observed even in a solid-state reaction. The molecular structure of ethyl 7-chloro-3-methyl-4H-1,4-benzothiazine-2-carboxylate (4d) was determined by single-crystal X-ray diffraction.

To better understand how forest management, phenology, vegetation type, and actual and simulated climatic change affect seasonal and inter-annual variations in soil respiration (R-s), we analyzed m ...

A series of new complexes, Mo(2)O(2)S(2)[S(2)P(OR)(2)](2) (where R = Et, n-Pr, i-Pr) and Mo(2)O(2)S(2)[S(2)POGO](2) (where G = -CH(2)CMe(2)CH(2)-, -CMe(2)CMe(2)-) have been prepared by the dropwise addition of an ethanolic solution of the ammonium or sodium salt of the appropriate O,O-dialkyl or -alkylene dithiophosphoric acid, or the acid itself, to a hot aqueous solution of molybdenum(V) pentachloride. The complexes were also formed by heating solutions of Mo(2)O(3)[S(2)P(OR)(2)](4) or Mo(2)O(3)[S(2)POGO](4) species in glacial acetic acid. The Mo(2)O(2)S(2)[S(2)P(OR)(2)](2) and Mo(2)O(2)S(2)[S(2)POGO](2) compounds were characterized by elemental analyses, (1)H, (13)C, and (31)P NMR, and infrared and Raman spectroscopy, as were the 1:2 adducts formed on reaction with pyridine. The crystal structures of Mo(2)O(2)S(2)[S(2)P(OEt(2))](2), Mo(2)O(2)S(2)[S(2)P(OEt)(2)](2).2NC(5)H(5), and Mo(2)O(3)[S(2)P(OPh)(2)](4) were determined. Mo(2)O(2)S(2)[S(2)P(OEt)(2)](2) (1) crystallizes in space group C2/c, No. 15, with cell parameters a = 15.644(3) Å, b = 8.339(2) Å, c = 18.269(4) Å, beta = 103.70(2) degrees, V = 2315.4(8) Å(3), Z = 4, R = 0.0439, and R(w) = 0.0353. Mo(2)O(2)S(2)[S(2)P(OEt)(2)](2).2NC(5)H(5) (6) crystallizes in space group Ponemacr;, No. 2, with the cell parameters a = 12.663(4) Å,b = 14.291(5) Å, c = 9.349(3) Å, alpha = 100.04(3) degrees, beta = 100.67(3) degrees, gamma = 73.03(3) degrees V = 1557(1) Å(3), Z = 2, R = 0.0593, and R(w) = 0.0535. Mo(2)O(3)[S(2)P(OPh)(2)](4) (8) crystallizes in space group P2(1)/n, No. 14, with cell parameters a = 15.206(2)Å, b = 10.655(3)Å, c = 19.406(3)Å, beta = 111.67(1) degrees, V = 2921(1)Å(3), Z = 2, R = 0.0518, R(w) = 0.0425. The immediate environment about the molybdenum atoms in 1 is essentially square pyramidal if the Mo-Mo interaction is ignored. The vacant positions in the square pyramids are occupied by two pyridine molecules in 6, resulting in an octahedral environment with very long Mo-N bonds. The terminal oxygen atoms in both 1 and 6 are in the syn conformation. In 8, which also has a distorted octahedral environment about molybdenum, two of the dithiophosphate groups are bidentate as in 1 and 6, but the two others have one normal Mo-S bond and one unusually long Mo-S bond.

A novel heterocyclic derivative of aluminium(III) [C6H4O{CHN(C6H5)}]2Al(μ-OPri)2Al(OPri)21 has been synthesized by the reaction of aluminium isopropoxide with N-phenylsalicylidene imine in 1 ∶ 1 molar ratio in refluxing anhydrous benzene. Reactions of 1 with alkoxyalkanols in 1 ∶ 1 and 1 ∶ 2 molar ratios in refluxing anhydrous benzene yielded binuclear complexes of the types, [C6H4O{CHN(C6H5)}]2Al(μ-OPri)2Al(OCH2CH2OR)(OPri) and [C6H4O{CHN(C6H5)}]2Al(μ-OPri)2Al(OCH2CH2OR)2 (where RCH3, C2H5 and C4H9n), respectively. All of these binuclear complexes have been characterized by elemental analysis, molecular weight measurements, and spectral studies. The FAB mass spectrum and 27Al NMR spectrum of 1 indicate that it is a discrete unsymmetrical dimer containing four- and six-coordinated aluminium(III) atoms as confirmed by its single crystal X-ray structure.

Crystals of triethyltelluronium bromide are cubic with space group I 4 +- 3m (No. 217), a 12.595(4) A and Z = 8. The structure refined to a final R value of 0.0290 for 164 unique “observed” reflections and is disordered with respect to the carbon atoms of the ethyl groups. The bromine atoms are involved in weak secondary interactions with the tellurium atoms to form isolated cubane like tetramers with Td symmetry. The crystal structure of Et3TeBr is also consistent with the IR, conductivity measurements and mass spectrometry which shows the presence of Et2TeBr+, EtTeBr+· and TeBr+ fragments. Spectroscopic data and conductivity measurements are also reported for the other triethyltelluronium salts which are all ionic.

The i.r. and Raman spectra of (CH 3 ) 2 PH and (CH 3 ) 2 PD have been recorded. The data indicate that the PH and PD bending modes occur at ∼ 720 cm −1 and ∼ 575 cm −1 respectively, leading to a reassignment of existing work.

The crystal structure of diethylammonium tetrachloro(p-phenoxyphenyl)tellurate has been determined by the heavy atom method. The crystals are monoclinic, space group C2/c, with unit cell dimensions a = 19.675(5), b = 7.634(3), c = 28.716(6) Å, β = 105.58(2)°, and Z = 8. For 2636 "observed" reflections (I > 3σ(I)), R = 0.030. The primary geometry about tellurium is based on a square pyramid with a secondary interaction on the vacant side of the tellurium coordination octahedron. The ions are apparently linked by weak interionic hydrogen bonding along the crystallographic b axis.

The symmetrically substituted disilyl chalcogenides (MenH3−nSi)2E where E = O, S, Se, Te; n = 0 → 3, have been prepared and characterized spectroscopically and by cleavage reactions. The synthetic routes include reactions of halogenosilanes with water, mercury(II) sulfide, lithium telluride, and complex thio- and seleno-aluminates. The spectroscopic properties of the(MeH2Si)2E and (Me2HSi)2E species, which have not been reported previously, are discussed in some detail.

The structure of MeGeI3 is orthorhombic with space groupPnma,a=6.374(3),b=10.412(4),c=12.683(4) A, andz=4. It has been solved by direct methods and refined by full-matrix least-squares techniques to a conventionalR factor of 0.0791 for 653 unique reflections. The crystal structure contains discrete molecules with mirror symmetry which are separated by normal van der Waals distances. The mean Ge-I distance is 2.500(2) A.

The i.r. and Raman spectra of dimethylarsine and its d1 analogue have been recorded and assigned. These assignments are supported by a normal co-ordinate analysis.

Complexes of the general formula [HgX2(Me3MCH2SeMe)]2, where M = Si, Ge; X = Cl, Br, I, have been prepared and characterized by 1H nuclear magnetic resonance and Raman spectroscopy. Crystal structures of [HgX2(Me3SiCH2SeMe)]2, where X = Cl, Br, and I (1, 2, and 3 respectively), show that they have centrosymmetric dinuclear structures. The crystals of 1 and 2 are monoclinic, while those of 3 are triclinic. For 1: P21/c, a = 14.235(11), b = 6.551(6), c = 14.211(9) Å, β = 117.33(5)°, Z = 2, and R = 0.0560. For 2: P21/c, a = 14.329(6), b = 6.695(2), c = 14.819(4) Å, β = 118.47(2)°, Z = 2, and R = 0.0540. For 3: [Formula: see text], a = 7.651(2), b = 8.387(2), c = 12.321(4) Å, α = 90.07(2), β = 91.80(2), γ = 116.02(2)°, Z = 1, and R = 0.0565. All three complexes show the expected pseudotetrahedral geometry about mercury. The stereochemical differences arise in the arrangement of the bulky trimethylsilylmethyl groups, which in the HgI2 adduct are rotated away from the centre of the molecule but which in the HgCl2 and HgBr2 adducts are turned towards the centre. These are the first dinuclear structures reported of HgBr2 and HgI2 adducts since it was demonstrated 46 years ago by Evans etal. that [HgBr2(AsBu3)]2 was present in [HgBr2(AsBu3)2•HgBr2].

This paper reports 13C chemical shifts for 20 methylgermanium compounds. These shifts are correlated against (i) the electronegativity of halogen in the Me3GeX compounds, (ii) the calculated charge on the carbon atom, (iii) the 1H shifts of the methyl protons, and (iv) the 13C shifts for the analogous carbon, silicon, and tin compounds.

The reaction of TeCl 4 with benzyltrimethylsilane in toluene gives condensation products, p -Me 3 SiCH 2 H 4 TeCl 3 and ( p -Me 3 SiCH 2 C 6 H 4 ) 2 TeCl 2 . Crystals of the latter are orthorhombic with space group Pbcn a 17.890(5), b 17.047(7) and c 8.169(3) A and Z = 4. The structure refined to a final R value of 0.0327 for 1490 unique “observed” reflections. The compound adopts a four-coordinate geometry with two Te⋯Cl secondary interactions completing a distorted octahedral configuration about the tellurium atom.

Methylarsine adducts of the type CH 3 AsH 2 BX 3 where X = Cl, Br, I were prepared and characterized by i.r. and Raman spectroscopy. The fundamental vibrations were assigned on the basis of C s molecular symmetry. A modified Urey-Bradley force field was utilized to calculate frequencies, potential energy distributions and force constants.

The i.r. and Raman spectra of PH3,BCl3, PD3,BCl3, PH3,BBr3, PD3,BBr3, PH3,BI3, and PD3,BI3 are reported. A normal co-ordinate analysis, utilizing a modified Urey–Bradley force field, confirms the assignments. All the adducts give best fits for a HPH angle of ca. 105–106°.

He(I) and He(II) pe spectra of the series Me2GeX2 (X = H, F, Cl) are reported. Assignments are based on comparisons with the spectra of related Me3GeX and MeGeX3 series as well as semi-empirical CNDO/2 calculations.

The infrared and Raman spectra of the methylgermanium fluorides CH 3 GeF 3 , (CH 3 ) 2 GeF 2 , and (CH 3 ) 3 GeF have been recorded. The fundamental frequencies for each molecule were assigned and supported by normal coordinate analyses based on a modified valence force field. The torsional modes were not observed.