SMe Groups Research Articles

Observed Divergence in the Attitudes of Incumbents and Supervisors as Subject Matter Experts in Job Analysis: A Study of the Fire Captain Rank

This study compares the attitudes of incumbent Fire Captains and their supervisors regarding critical aspects of a Fire Captain's job. Fire Captains and supervisors (Fire Chief, Deputy Fire Chiefs, and Division Chiefs) were held as separate subject matter expert groups in an analysis of the Captain's job. Data regarding the attitudes held by these SME groups concerning the criticality of Fire Captain job tasks and work required knowledge, skills, abilities and worker characteristics were collected through task inventory and worker attribute surveys. These data were compared to determine the degree to which the SME groups agreed upon the critical aspects of the Fire Captain's job. The data indicate that Fire Captains and their supervisors substantially agree upon the criticality of Fire Captain tasks, and moderately agree upon the criticality of requisite Fire Captain attributes. The findings of this study have applications for current job analysis practice as well as point out areas in need of further examination.

The effect of replacing carbonyl with acetonitrile on the reactivity of the bimetallic system [Mo 2Cp 2(μ-SMe) 3(L) 2] + (L=CO, CH 3CN). Crystal structure of [Mo 2Cp 2(μ-SMe) 2(CH 3CN) 4](BF 4) 2

[Mo 2Cp 2(μ-SMe) 3(CH 3CN) 2](BF 4) ( 1) reacts with H[BF 4] in acetonitrile at room temperature to give the tetrakis (acetonitrile) compound [Mo 2Cp 2(μ-SMe) 2(CH 3CN) 4](BF 4) 2 ( 3) through replacement of one SMe bridge by two terminal CH 3CN ligands. In sharp contrast, the carbonyl analogue [Mo 2Cp 2(μ-SMe) 3(CO) 2] + ( 2) fails to undergo a similar reaction. This suggests that the electronic properties of the ancillary ligands L in the [Mo 2Cp 2(μ-SMe) 3L 2] + moiety govern the activation of a sulfur atom in protonation reactions. An X-ray diffraction study shows that 3 contains two CpMo(CH 3CN) 2 units bridged by two SMe groups and linked by a long Mo–Mo bond of 3.000(1) Å.

Reactions of the cluster complex [Ru5(μ5-C2)(μ-SMe)2(μ-PPh2)2(CO)11] with terminal alkynes HCCR (R = Ph, But or SiMe3)

Reaction of the dicarbon-containing complex [Ru5(µ5-C2)(µ-SMe)2(µ-PPh2)2(CO)11] 1 with monosubstituted alkynes HCCR (R = Ph, But or SiMe3) yielded [Ru5(µ5-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)10] (R = Ph, But or SiMe3) in which the Ru5 pentagon in 1 is retained. Coupling of the C2 and alkyne moieties forms a CCCHCR ligand which in combination with one Ru atom forms a metallacycle. The unsubstituted terminal carbon has a strong carbidic interaction with four of the Ru atoms. Carbonylation of the R = Ph and SiMe3 complexes yields [Ru5(µ5-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)11] (R = Ph or SiMe3), in which one Ru atom has been extruded from the cluster, although retained by co-ordination to bridging PPh2, SMe and hydrocarbon ligands. A minor product in each case was identified as [Ru5{µ5-CC[C(O)SMe]CHCR}(µ-SMe)(µ-PPh2)2(CO)10 (R = Ph or SiMe3). Here, the organic ligand is formed by combination of the CCCHCR ligand with CO and one of the SMe groups and is attached to an Ru5 core with an open-envelope conformation. Pyrolysis of [Ru5(µ-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)11] afforded [Ru5(µ5-CCCHCR)(µ-SMe)2(µ-PPh2)2(CO)10] and [Ru5(µ5-CCCHCR)(µ3-SMe)(µ-SMe)(µ-PPh2)2(CO)9] (R = Ph or SiMe3), in which one SMe group becomes triply bridging. The complex [Ru5{µ5-CC(CHCSiMe3)C(=CHSiMe3)CO}(µ-SMe)2(µ-PPh2)2(CO)8], in which the organic ligand, formed by combination of CO, HC2SiMe3 and CCHSiMe3 molecules, is attached to the opposite side of the open-envelope cluster from that in [Ru5{µ5-CC[C(O)SMe]CHCR}(µ-SMe)(µ-PPh2)2(CO)10], has also been isolated. The structures of five complexes were determined from single-crystal X-ray studies.

Reaction of a dicarbon Ru5 cluster with CO: crystal structures of [Ru5(μ4-C2)(μ-SMe)2( μ-PPh2)2(CO)13] and [Ru4(μ4-C2)(μ-SMe)2( μ-PPh2)2(CO)10

C. J. Adams, M. I. Bruce, B. W. Skelton, A. H. White, G. Frapper and J. Halet, J. Chem. Soc., Dalton Trans., 1997, 371 DOI: 10.1039/A605529J

Dithio and Thiono Esters, 64. Attempted Synthesis of Bis(alkylthio)‐Orthoqinodimethanes from Dithiobenzoates

Abstracto‐Alkyl substituted dithiobenzoates 3 are S‐methylated with trimethyloxonium tetrafluoroborate to form the stable bis(alkylthio)arylmethylium tetrafluoroborates 4. Their deprotonation with LiHMDS takes place either at the o‐alkyl groups to form the postulated o‐quinodimethanes 5 as intermediates or at the SMe groups to give the thiocarbonyl ylides 7. Both intermediates dimerize to furnish either the dibenzo[a,e]cyclooctenes 6 or the 1,4‐dithianes 8/9. Their trapping with N‐phenylmaleimide (10) leads to the formation of the cycloadducts 11 or 12. The structure of 8e was confirmed by X‐ray analysis. p‐Substituted dithiobenzoates 13 show a similar reaction sequence. Their bis(methylthio)arylmethylium salts, however, are only deprotonated at one of the SMe groups to give the 1,4‐dithianes 15/16. Sterically crowded 1,4‐dithianes (e.g. 8d,e/9d,e) rearrange with traces of acid to the ring opened stilbenes 18 and 19.

Cluster chemistry: XCIV. Preparation and characterisation of some Ru 5 clusters containing vinylidene ligands

Reactions of the open Ru 5C 2 cluster complex, Ru 5(μ 5-C 2)(μ-SMe) 2(μ-PPh 2) 2(CO) 11, ( 1), with hydrogen or olefins afforded electron-rich vinylidene complexes Ru 5(μ 3-CCHR)(μ 3-SMe) 2(μ-PPh 2) 2(CO) 10 [ 2; R  H and 3; R  CHCHF′ (R′  H, Me, Ph and CO 2Et)]. X-ray structural determinations have been carried out on 2 and 3 (R′  H, Me and Ph). These complexes contain an Ru 5 core consisting of three edge-sharing triangles; the vinylidene ligand, which spans one of the Ru 3 faces, is fluxional, with concomitant changes occurring in the orientations of the SMe, PPh 2 and CO groups. The clusters have 80 cluster valence electrons, the Ru-Ru separations being elongated (av. 3.03 Å) as a result of occupation of Ru-Ru anti-bonding orbitals.

Komplexchemie perhalogenierter Cyclopentadiene und Alkine XVI. Darstellung von π-Cyclopentadienylkomplexen mit zwei und drei Chalkogensubstituenten am Ring, [C 5Cl 4- m(ER) m(ER′)]ML n (ML n  Mn(CO) 3, Fe(C 5H 5); m = 1 oder 2; E  S, Se; R, R′ Me, Ph). Struktur von [C 5Cl 3(SMe) 2][C 5H 5]Fe

(1,2,3,4,5)Pentachloroferrocene reacts with butyl lithium and then MeSSMe to give [C 5Cl 4(SMe)]FeCp (Cp = η 5-C 5H 5) ( 1). By repeating this procedure, [C 5Cl 3(SMe) 2)FeCp ( 2) and [C 5Cl 2(SMe) 3]FeCp ( 3) can be obtained. A crystal structure determination of 2 shows the two SMe groups in 1,3-orientation. A number of unsymmetrical cymantrenylbis- and tris(thioethers) ( 4– 6) was prepared in a similar manner from [C 5Cl 4(SR)]Mn(CO) 3 or [C 5Cl 3(SR) 2]Mn(CO) 3 (R  Me, Ph), respectively. The cymantrene selenoethers [C 5Cl 5− n (SeR) n ]Mn(CO) 3 ( 7– 10) (R  Me, n = 1, 2, 3; R  Ph, n = 2) were also prepared.

Koordinationschemie perhalogenierter Cyclopentadiene und Alkine, XI [1].<br />Darstellung einiger Cymantrenyl-mono- und bis-thioether mit einer weiteren funktionellen Gruppe am Cyclopentadienylring. Molekülstruktur von [C5Cl2(SMe)2(PPh2)]Mn(CO)3 / Coordination Chemistry of Perhalogenated Cyclopentadienes and Alkynes, XI [1]<br />Synthesis of Some Cymantrene Mono- and Bis-Thioethers with One Additional Functional Group on the Cyclopentadienyl Ring. Molecular Structure of [C5Cl2(SMe)2(PPh2)]Mn(CO)3

Chiral Cyclopentadienyl Complexes, Crystal Structure The reaction of [C5Cl4(SMe)]Mn(CO)3 (la) with n-butyllithium and the electrophiles SiMe3Cl, CO2, or PPh2Cl regiospecifically yields the chiral 1,3-disubstituted functional cymantrene thioethers [C5Cl3(SMe)R]Mn(CO)3 (R = SiMe3 (2), COOLi (3a), PPh2 (4)). 3 a can be protonated to give the corresponding carboxylic acid (3b), which in turn can be transformed to the acid chloride [C5Cl3(SMe)(COCl)]Mn(CO)3 (3c). 3c reacts with NaN3 to yield after work-up the urea derivative OC[[NH—C5Cl3(SMe)]Mn(CO)3]2 (3d). Using the cymantrene bisthioethers [C5Cl3(SR)2]Mn(CO)3 (R = Me, 5a, Ph, 5b) as starting materials, the carboxyl derivatives [C5Cl2(SMe)2(COR)]Mn(CO)3 (R = OLi, 6a, OH, 6b, Cl, 6c) and the potential organometallic S,P-chelate ligands [C5Cl2(SR)2(PPh2)]Mn(CO)3 (R = Me, 7a, Ph, 7b) can be obtained. The crystal structure determination of 7a (C22H16O3PS2Cl2Mn, monoclinic, P 21/c, a = 18.714(6) A, b = 9.506(3) A, c = 14.475(3) Α, β = 109.18(2)°, V = 2432.1(12) Α3, Z = 4) shows an orientation of the neighbouring PPh2- and SMe groups, that allows chelation of an additional metal fragment.

Formation of the dinuclear iron–nitrosyl complex [Fe2(SMe)2(NO)4] by incorporation of SMe groups from methionine in reactions with iron(II) salts and nitrite

The dinuclear iron–nitrosyl complex [Fe2(SMe)2(NO)4] has been isolated from reactions of iron(II) salts and sodium nitrite with methionine, under reaction conditions relevant to food processing.

Nuclear magnetic resonance investigations of a novel intramolecular methylthio replacement process in palladium(II) and platinum(II) complexes of mixed sulfur–phosphine ligands

A series of palladium(II) and platinum(II) complexes with the mono- and bis-chelate ligands bis[o-(methylthio)phenyl]phosphine and tris[o-(methylthio)phenyl]phosphine have been prepared and characterised. Despite the potential tridenticity of the first ligand it acts as a P/S monochelate to form square-planar complexes of type [M{PPh(C6H4SMe-o)2}X2](M = Pd, X = Cl, Br or I; M = Pt, X = Cl). Variable-temperature one- and two-dimensional NMR spectroscopy showed that pyramidal inversion of the co-ordinated sulfur atoms was accompanied by an exchange of pendant and bound methylthio groups. The ΔG‡ values for both processes were in the range 43–69 kJ mol–1, being strongly metal and halogen dependent. The bis(chelate) complexes [M{P(C6H4SMe-o)3}2][ClO4]2 are also square planar with metal co-ordination involving one phosphorus and one sulfur of each ligand, the other two pairs of SMe groups being unco-ordinated. The X-ray crystal structure of [Pd{P(C6H4SMe-o)3}2][ClO4]2 shows the co-ordinated S-methyls to be mutually cis with respect to the metallocycle plane. In low-temperature solutions of this complex this cis form is assumed to be predominant. At higher solution temperatures a facile intramolecular exchange of all six methylthio groups occurs. The energy and probable mechanism of this fluxion are reported.

JOB ANALYSIS: THE COMPOSITION OF SME SAMPLES

It is common for job analysts to solicit information from incumbents and supervisors (Subject Matter Experts or SMEs) when conducting a job analysis. These SMEs are asked to provide ratings on salient dimensions (e.g., frequency and importance of tasks that comprise the job). In constructing samples of SMEs for this purpose, it is reasonable to consider any possible influences that might bias or systematically influence the task ratings. The present paper considers the possible influence of SME demographic characteristics on task ratings of frequency. The tasks comprising the job of patrol officer in a large city were rated for frequency by approximately 700 incumbents. These ratings were gathered in two different years, 1982 and 1984. The total data set was used to conduct a components analysis of the 444‐item task inventory. The first eight principal components were considered the dependent variables and four demographic characteristics the independent variables in an analysis of the 1982 data set. Analysis of variance and follow‐up tests indicated that incumbent experience had a substantial influence on task ratings. Educational level and race had minimal effects on ratings. The sex factor was confounded by the experience factor, making interpretation of the sex effect equivocal. Mechanisms that might account for the experience effect are discussed. It was concluded that incumbent experience is a salient issue in job analysis using SME groups.

Structural dependencies of pyramidal sulphur inversion in halogenotricarbonylrhenium(I) complexes of mono- and bis-( o-methylthio) derivatives of triphenylphosphine

A series of new halogenotricarbonylrhenium(I) complexes of the hybrid sulphur- phosphine ligands [ o-(methylthio)phenyl]diphenylphosphine (SP) and bis-[ o-(methylthio) phenyl]phenylphosphine (DSP) have been prepared and characterized. Both ligands act as sulphur/phosphorus mono-chelates, despite the potential tridenticity of DSP. No evidence of an intramolecular methylthio exchange process involving the uncoordinated and coordinated SMe groups was detected in the [ReX(CO) 3(DSP)] (X = Cl, Br, I) complexes, in contrast to the analogous [PdX 2(DSP)] and [PtX 2(DSP)] complexes. Solution NMR studies revealed pyramidal inversion of the coordinated sulphur atoms in the [ReX(CO) 3(SP)] and [ReX(CO) 3(DSP)] complexes, with energy barriers [Δ G ‡(298 K)] in the range 51–55 kJ mol −1.

The syntheses and fluxional properties of mixed halide/methylthio bridged tetramers of trimethylplatinum(IV)

Syntheses of the trimethylplatinum(IV) tetramers [(PtMe 3SMe) 2 (PtMe 3X) 2] (X = Cl, Br or I) and [(PtMe 3SMe) 3 (PtMe 3Cl)] are reported. Both classes of tetramer, by virtue of the two types of bridging ligand, contain two distinct platinum environments. This leads to four different Pt-methyl environments for the structures [(PtMe 3SMe) 2 (PtMe 3X) 2] and three such environments for the tetramer [(PtMe 3SMe) 3 (PtMe 3Cl)]. Variable temperature 1H NMR studies show that methyl scrambling occurs in each PtMe 3 moiety with activation energies (Δ G ‡ (298 K)), in the range 61–72 kJ mol −1. PtMe 3 groups bonded to two X ligands and one SMe ligand undergo slightly less facile fluxion than those groups attached to one X and two SMe groups. The implications of this fluxionality for symmetrical tetramers (e.g. [(PtMe 3) 4] are discussed.

Reactions of CpFe(CO) 2( [formula omitted]) +, CpFe(CO) 2[C(SMe) 2] + and related carbene complexes with reducing agents and nucleophiles. The structure of {CpFe(CO) 2[C(SMe) 2]}PF 6

The reduction of CpFe(CO) 2( COCH 2CH 2O ) + ( I) with one equivalent of sodium naphthalenide (NaNp) yields [CpFe(CO) 2] 2 ( II), CO 2 and C 2H 4. The same reduction of CpFe(CO) 2[C(SMe) 2] + ( X), however, gives II, CpFe(CO) 2[C(SMe) 3] ( XII), CpFe(CO)[C(SMe)(SMe) 2] ( XIII) and [CpFe(CO)- (SMe)] 2. Small amounts (0.1 equivalent) of NaNp catalyze reactions of I and X with phosphines to give a mixture of CO- and carbene-substituted products, CpFe(CO)(L)( COCH 2CH 2O ) +, CpFe(CO) 2(L) +, Cp- Fe(CO)(L) 2 + and CpFe(CO)(L)[C(SMe) 2] + (L = PMePh 2); a mechanism involving radical intermediates is proposed for the reactions. Complex I reacts with anions (I −, Cl −, MeO −, NCS −, PhCH 2S −) to give the ring-opened alkoxycarbonyl complexes CpFe(CO) 2- [C(O)OCH 2CH 2X]. With oxidizing agents such aa Me 3NO, the dioxycarbene ligand in I is converted to ethylene carbonate, O COCH 2CH 2O . An X-ray diffraction study of X shows the carbene moiety to be planar with the SMe groups in a syn and anti conformation. The plane of the carbene ligand is oriented ‘crosswise’ with respect to the CO groups.

Synthetic and NMR spectroscopic studies on the 2,1,3-benzophosphadiazine ring system

Alkylation reactions of 2,3-dihydro-2-mercapto-2,1,3-benzophosphadiazine-4(1 H)-thione-2-sulphide are described; reaction with methyl iodide occurs sequentially to produce mono-, di- and tri-methylated derivatives. Reaction of 1,2-dihydro-1-methyl-2,4-bis(methylthio)-2,1,3-benzophosphadiazine with p-chloroaniline leads to a product formed by displacement of SMe groups both from carbon and phosphorous. Lawesson's reagent reacts with o-aminobenzamide to yield 1,2-dihydro-2,4-bis( p-methoxyphenyl)-2,1,3-benzophosphadiazine-2-sulphide. Details of 13C and 31P NMR used to identify these compounds are discussed.

Nuclear magnetic resonance investigations of configurational non-rigidity in dinuclear platinum(IV) complexes. Part 7. Intramolecular rearrangements in complexes of tris(methylthio)methane

The ligand tris(methylthio)methane, HC(SMe)3, has been used to form dinuclear platinum(IV) complexes of type [(PtXMe3)2{HC(SMe)3}](X = Cl or Br), where the ligand bridges the pair of Pt atoms via two of its SMe groups. Variable-temperature 1H n.m.r. studies in the range –90 to 70 °C revealed inversion of the pyramidal S atoms, a 1,3-metal pivoting fluxion, and a scrambling of the Pt-methyl environments by a PtMe3 rotation mechanism. The latter two fluxions are concerted and involve a common transition state. Activation energies for the various dynamic processes are in the range 45–72 KJ mol–1.

Organothiometallate - alkyne addition products. The crystal and molecular structure of [(η 5-C 5H 5) [formula omitted]Me} (CO) 2

The title compound is the final product of the reaction between dimethylacetylene dicarboxylate and [(η 5-C 5H 5)W(SMe) (CO) 3 ]. Its molecular structure has been established by an x -ray analysis based on 3301 diffractometric intensities. The crystals are monoclinic, space group P 2 1/ a , with four molecules in a cell of dimensions a = 10.323(2), b = 16.016(2), c = 10.437(2)», β = 103.56(2)°. After least-squares refinement R = 0.036. The tungsten co-ordination is square-pyramidal, the apical site being occupied by the centroid of the cyclopentadienyl ring. The basal co-ordination sites contain two carbonyl groups and also the sulphur and σ-bonded carbon atoms of a chelating carbothiolic methyl ester ligand derived from the incoming alkyne and CO and SMe groups of the original complex. The W-S and σ-W-C bond lengths are 2.440(2) and 2.194(7)».

Spectroscopic and structural studies on cobalt complexes of the methyl esters of dithiocarbazic and 2-methyldithiocarbazic acids. Crystal structure of [Co{NH2NHC(S)SMe}{NH2NC(S)SMe}2]Cl·H2O

The ligand behaviour of methyl esters of dithiocarbazic acid NH2NHC(S)SMe (HL) and of 2-methyldithiocarbazic acid NH2NMeC(S)SMe (MeL) in cobalt complexes has been investigated. Complexes of CoII and CoIII have been prepared under different conditions and characterized by their electronic and i.r. spectra. HL can act as a ligand when neutral or when deprotonated (L–); MeL can be deprotonated at the terminal N only after co-ordination. The crystal structure of [Co(HL)L2] Cl·H2O has been determined by X-ray diffraction methods: crystals are monoclinic, space group P21/c, Z= 4, in a unit cell of dimensions a= 12.085(9), b= 8.903(8), c= 17.287(16)A, and β= 104.2(1)°. The structure has been solved by Patterson and Fourier methods and refined by block-diagonal least squares to R= 0.042 for 1 993 reflections. It consists of cis-octahedral [Co(HL)L2]+ cations, in which one neutral and two deprotonated molecules of methyl dithiocarbazate act as chelating ligands, chloride anions, and water molecules, held together by a network of hydrogen bonds. The bond distances in the co-ordination polyhedron are: Co–S 2.203(4), Co–N 1.993(6)A for the neutral ligand; Co–S 2.212(5) and 2.218(3), Co–N 1.977(6) and 1.980(6)A for the deprotonated ligands. The conformation of the three ligands is cis,cis, i.e. with both NHNH2 and SMe groups bent towards the CS bond.