Inorganic Chemistry Communications 26 (2012) 72–76 Contents lists available at SciVerse ScienceDirect Inorganic Chemistry Communications journal homepage: www.elsevier.com/locate/inoche Re VN and Tc VN complexes with a novel tetradentate hybrid benzamidine/ thiosemicarbazone ligand Hung Huy Nguyen a,⁎, Juan Daniel Castillo Gomez b, Ulrich Abram b,⁎ a b Department of Chemistry, Hanoi University of Science, 19 Le Thanh Tong, Hanoi, Viet Nam Freie Universität Berlin, Institute of Chemistry and Biochemistry, Fabeckstr 34-36, D-14195 Berlin, Germany a r t i c l e i n f o Article history: Received 28 August 2012 Accepted October 2012 Available online 12 October 2012 Keywords: Rhenium Technetium Thiourea derivatives Thiosemicarbazones Cyclization X-ray structure a b s t r a c t N-(diethylthiocarbamoyl)benzimidoyl chloride reacts with o-aminoacetophenone 4-methylthiosemicarbazone under formation of a novel N2S2 benzamidine/thiosemicarbazone ligand (H2L) The reaction of H2L with [ReNCl2(PPh3)2] yields a red complex of the composition [ReN(L)] The molecular structure of [ReN(L)] reveals a square-pyramidal environment around the Re atom, in which the organic ligand occupies all four positions of the equatorial plane The reaction of H2L with [TcNCl2(PPh3)2] results in a mixture of [TcN(L)] and a side-product of the composition [TcN(PPh3){Et2NC(S)NH}(L′)] (L′ = 1,10b-dimethyl-5-phenyl-1,10bdihydro-[1,2,4]triazolo[1,5-c]quinazoline-2-thiolate) The formation of diethylthiourea and HL′ is the result of a metal-driven decomposition of H2L followed by cyclization © 2012 Elsevier B.V All rights reserved Tri-, tetra- or poly-dentate ligands are of particular interest for medical or biological applications (including nuclear medical imaging or therapeutic procedures), since they form stable or kinetically inert complexes Previous studies have shown that mono- and bidentate ligand systems may suffer from insufficient in vivo stability due to rapid ligand exchange reactions with plasma components [1–7] For common technetium(V) and rhenium(V) cores, ligands with ‘medium’ and ‘soft’ donor atoms are particularly recommended [1–9] Thus, chelators with a mixed sulfur and nitrogen donor sphere should be very suitable and some of them have found application in routine nuclear medical procedures [10–12] N-[N′,N′-(dialkylamino(thiocarbonyl)] benzimidoyl chlorides (1) readily react with ammonia or primary amines under formation of benzamidine-type compounds [13,14] By the use of thiosemicarbazide in similar reactions, we were recently successful in the synthesis of a series of tridentate benzamidine/ thiosemicarbazide ligands [15,16] These novel ligands form stable complexes with both oxo- and nitridorhenium(V)/technetium(V) cores [17,18] Additionally, the organic ligands, their oxorhenium(V) complexes and their gold(III) complexes show promising cytotoxicity on breast cancer cell lines [18,19] ⁎ Corresponding authors E-mail addresses: nguyenhunghuy@hus.edu.vn (H.H Nguyen), abram@chemie.fu-berlin.de (U Abram) 1387-7003/$ – see front matter © 2012 Elsevier B.V All rights reserved http://dx.doi.org/10.1016/j.inoche.2012.10.004 In a recent communication, we published ReO and TcO complexes with a novel class of tetradentate thiocarbamoylbenzamidine ligands derived from o-phenylenediamine (2) [20] It could be shown that the chelates are perfectly stable and resist ongoing ligand exchange This encouraged us to develop novel tetradentate ligands, which possess different coordination sites Such hybrid ligands may provide more flexibility for the coordination of various metal ions Here, we present the synthesis of a tetradentate thiosemicarbazone/ thiocarbamoylbenzamidine hybrid ligand (H2L) and its reactions with [ReNCl2(PPh3)2] and [TcNCl2(PPh3)2] together with the structures of their products N-(diethylthiocarbamoyl)benzimidoyl chloride 1a readily reacts with o-aminoacetophenone 4-methylthiosemicarbazone in the presence of a supporting base like Et3N under formation of the ligand H2L in high yields In order to avoid undesired side-reactions, dry EtOH was used instead of acetone for the preparation of the ligand H2L [21] The progress of the reaction can easily be controlled by thin-layer chromatography, and the ligand H2L precipitates directly from the reaction mixture as a pure yellow powder (Scheme 1) The IR spectrum of H2L is characterized by broad bands of the νN\H vibrations in the region around 3200 cm−1 and sharp, intense absorptions at 1717 cm−1 and 1686 cm−1 which are assigned to the νC_N stretches The 1H NMR spectrum of the uncoordinated ligand shows three different N\H resonances at 7.64 ppm, 8.41 ppm and 12.62 ppm Two sets of well separated signals corresponding to the resonance of two ethyl groups of the NEt2 moiety are observed in the 1H NMR spectrum of H2L This indicates that they are magnetically nonequivalent, which is due to a hindered rotation around the C-NEt2 bond, which is common for many uncoordinated thiocarbamoylbenzamidines as well as for H.H Nguyen et al / Inorganic Chemistry Communications 26 (2012) 72–76 73 N NH2 O NH 4-methylthiosemicarbazide 1a,Et3N,EtOH N S HN HN N NH S N S HN HN H 2L Scheme Synthesis of H2L N [ReNCl2(PPh3)2] + H 2L CH2Cl2,Et3N N N N S Re -PPh3,HNEt3Cl N S N HN Scheme Reaction of H2L with [ReNCl2(PPh3)2] their rhenium(V) or technetium(V) complexes [14–19] In contrast to this behavior, the C\NHMe bond of the thiosemicarbazone unit is flexible enough to give only one methyl signal at 3.08 ppm H2L readily reacts with [ReNCl2(PPh3)2] in boiling CH2Cl2 under formation of a red solid of the composition [ReN(L)] [23] The addition of a supporting base such as Et3N allows the synthesis to be carried out at ambient temperature with higher yields (Scheme 2) The product is only sparingly soluble in alcohols, but soluble in CH2Cl2 or CHCl3 and can be recrystallized from a CH2Cl2/MeOH solution The IR spectrum of [ReN(L)] reveals a moderate absorption at 3417 cm − 1, which is assigned to the νN\H stretch of the MeNH-CS group The absorption band of the νC_N vibration is observed as a very intense peak at 1527 cm − This corresponds to a strong bathochromical shift of about 190 cm − and indicates chelate formation with a large degree of π-electron delocalization within the chelate rings The 1H NMR spectrum of the compound shows the absence of N\H resonances of benzamidine and thiocarbazone moieties and a high field shift of the signal corresponding to N\H in the CS-NHMe residue to 5.28 ppm This reflects that the organic ligand is coordinated to Re in the form {L} − The hindered rotation around the C\NEt2 bond results in two magnetically inequivalent ethyl groups Thus, two triplet signals of the methyl groups in the \NEt2 residue are observed in the 1H NMR spectrum of [ReN(L)] measured at room temperature However, the proton signals of the two methylene groups, which should consequently be two quartets, appear as four well separated multiplet resonances at 3.58, 3.68, 4.32 and 4.40 ppm This pattern of the methylene signals has previously been rationalized by the rigid structure of the tertiary amine group, which makes the methylene protons magnetically nonequivalent with respect to their axial and equatorial positions [24] A crystallographic study of single crystals of [ReN(L)] shows a five-coordinate rhenium(V) complex (Fig 1) [25] The rhenium atom has a distorted square-pyramidal environment with the terminal nitrido ligand in apical position The ligand {L}2− is equatorially Table Selected bond lengths (Å) and angles (°) in [ReN(L)] and [TcN(L)] Fig Ellipsoid representation of the molecular structure of [ReN(L)] [27] M–N1 M–S1 M–S12 M–N5 M–N9 N1–M–S1 N1–M–S12 N1–M–N5 N1–M–N9 [ReN(L)] [TcN(L)] 1.668(4) 2.347(1) 2.340(1) 2.054(4) 2.120(4) 105.7(1) 110.3(1) 106.7(2) 100.9(2) 1.617(5) 2.359(1) 2.347(2) 2.057(4) 2.119(4) 105.2(2) 110.3(2) 107.8(2) 101.6(2) 74 H.H Nguyen et al / Inorganic Chemistry Communications 26 (2012) 72–76 N N CH2Cl2,Et3N [TcNCl2(PPh3)2] + H2L -PPh3,HNEt3Cl N N Tc N N N H N S + S N S N N Tc N S PPh3 N main product HN side product Scheme Reaction of H2L with [TcNCl2(PPh3)2] coordinated via its N2S2 donor set The Re atom is situated 0.604(1) Å above the basal plane toward the nitrido ligand The N1–Re–N/S angles fall in the range between 100.9(2) and 110.3(1)° The Re\N1 bond length of 1.668(4)Å is in the expected range for rhenium–nitrogen triple bonds [9] More bond lengths and angles are summarized in Table The reaction of H2L with the analogous technetium precursor [TcNCl2(PPh3)2] proceeds in a slightly different way [28] Besides the main product [TcN(L)], which can be obtained as large orange-red crystals, an unexpected yellow side-product is formed in moderate yields (Scheme 3) Both compounds are sparingly soluble in MeOH and crystallize from the reaction mixture after the addition of MeOH as big crystals which can be separated mechanically IR and 1H NMR spectra of [TcN(L)] mainly exhibit the same patterns as described for the rhenium complex described above, indicating a similar bonding situation An X-ray diffraction study confirms the analogous arrangement of the ligands [29] The technetium atom also reveals a distorted square-pyramidal coordination sphere with an apical {N}3− ligand Since the molecular structures of [ReN(L)] and [TcN(L)] are virtually identical, no extra figure of the Tc compound is shown in this communication Selected bond lengths and angles of the technetium complex are contained in Table and compared to the values of the rhenium compound The atomic labeling scheme of the rhenium complex has also been applied for the Tc compound With the reported structural data, [TcN(L)] resembles the main features of the structures of the hitherto only two TcVN complexes with tetradentate N2S2 ligands [30,31] The IR spectrum of the side-product is quite similar to that of [ReN(L)], except that the N–H band is sharp and long-wave shifted to 3363 cm−1 However, the 1H NMR spectra of the two compounds are completely different In 1H NMR spectrum of the yellow compound, the ethyl resonances still reflect the rigid structure of the tertiary amine nitrogen atom of the thiourea group, but the observed signals Fig Ellipsoid representation of the molecular structure of [TcN(PPh3){Et2NC(S) NH}(L′)] [27] Selected bond lengths and angles are summarized in Ref [33] are strongly high-field shifted Despite the fact that in the 1H NMR spectrum of [TcN(L)], the CH3-NH signal of the thiosemicarbazone moiety appears as a doublet at 3.05 ppm due to coupling with the adjacent N–H proton, the corresponding resonance of the yellow side-product is a singlet at 3.66 ppm and another methyl signal appears at 1.41 ppm This resonance is at an even higher field than that in the spectrum of the uncoordinated H2L From the 1H NMR discussion, we can conclude that the main skeleton of the organic ligand ‘{L}2− is not maintained in the side-product The 31P NMR spectrum reveals a singlet at 48.86 ppm and, thus, indicates the presence of a PPh3 ligand in the coordination sphere of the metal However, the structure of the compound could not be deduced unambigously from the spectroscopic methods, and an X-ray diffraction study was performed also for this complex [32] Fig depicts an ellipsoid presentation of its molecular structure The structural study confirms the assumed decomposition of the ligand H2L during the reaction with the technetium precursor and the formation of a heterocyclic thiol/thione HL′ and N,N-diethylthiourea (see also Scheme 4) The coordination environment of the technetium atom is best described as a distorted square pyramid with an apical nitrido ligand The basal plane contains three ligands: the heterocyclic thiolato ligand {L′} −, which binds monodentate via its sulfur atom, a bidentate N,N-diethylthioureido ligand and PPh3, which is arranged in a trans position to the nitrogen donor atom The bonding situation in the ligand {L′} − reveals the sp hybridization of the carbon atoms C11 and C4 Although some delocalization of the π-electron density is found in the skeleton of {L′} −, the C4–N5 and C11–N10 bond lengths of 1.32(1) Å and 1.31(1) Å, respectively, are slightly shorter than the other carbon–nitrogen bonds and indicate more double bond character The Tc–S12 distance of 2.373(2) Å is 0.03 Å shorter than the Tc–S1 bond length Delocalization of the negative charge is also observed in the four-membered chelate ring of the N,N-diethylthioureido ligand and is reflected by the C2–N3 and C2–S1 bond lengths, which fall between the values of carbon–nitrogen and carbon–sulfur single and double bonds The solid state structure of [TcN(PPh3){Et2NC(S)NH}(L′)] contains relatively large lipophilic voids, which are not filled by solvent molecules and form channel-like structures along the crystallographic c axis They are bounded by the phenyl and alkyl residues of the ligands, which most probably avoids the stabilization of polar solvent molecules such as methanol or CH2Cl2 inside these channels The formation of [TcN(PPh3){Et2NC(S)NH}(L′)] is reproducible and clearly a result of the decomposition of H2L However, it is worth mentioning that a similar decomposition is not found in the synthesis of the analogous rhenium complex, whether under the same conditions, nor with reflux More interestingly, the technetium complex [TcN(L)] is perfectly stable, even under reflux conditions in CH2Cl2 with and without the addition of a base Additionally, the purity of the ligand H2L was confirmed by different spectroscopic methods as well as by elemental analysis These synthetic evidences suggest that the two technetium compounds are formed independently and the decomposition of H2L only occurs during the formation of [TcN(PPh3){Et2NC(S)NH}(L′)] H.H Nguyen et al / Inorganic Chemistry Communications 26 (2012) 72–76 75 N + N N NH S N N NH NH N ClCl Tc Et2N S PPh3 N Et3N -HNEt3Cl H N N NH Et3N S + N - HNEt3Cl H N N S N N Tc N S PPh3 Cl Tc N PPh3 S Scheme Proposed formation of [TcN(PPh3){Et2NC(S)NH}(L′)] A possible mechanism is proposed in Scheme It is supposed that one of the chlorido ligands of [TcNCl2(PPh3)2] is first exchanged by the thiourea sulfur atom of H2L This is confirmed by a previously published reaction pattern of [ReOCl2(PPh3)3] with a benzamidine derived from glycine ester, in which an intermediate S-thiourea monodentate product was successfully isolated [16] Subsequently, a phosphine ligand can be replaced either by the N5 or the N3 donor atoms The first situation results in the formation of a benzamidine chelate ring and consequently produces [TcN(L)] (not shown in Scheme 4) In the second case, an intermediate cationic complex (3) is formed, in which the positive charge is partially located in the atom C4 This allows a nucleophilic attack with subsequent bond cleavage and cyclization The resulting N,N-diethylthioureido ligand remains coordinated to the technetium atom and forms the intermediate complex The released heterocyclic thion deprotonates and replaces the chlorido ligand in under formation of the final product [TcN(PPh3){Et2NC(S)NH}(L′)] In the present communication, we could show that the novel benzamidine/thiosemicarbazone hybrid ligand forms stable complexes with technetium and rhenium, but may be only partially suitable for applications in nuclear medical labeling procedures, since during the reactions with common Tc compounds unexpected ligand cleavage and cyclization reactions may occur The fact that this behavior is not observed with the analogous rhenium compound, puts a serious question mark over the more or less generally accepted opinion that model studies with rhenium compounds are sufficient to predict the behavior of analogous technetium complexes reliably [14] [15] [16] [17] [18] Appendix A Supplementary material [22] [23] [19] [20] [21] Supplementary data to this article can be found online at http:// 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Eshima, D.L Johnson, J Nucl Med 27 (1986) 111 [11] D Eshima, D Taylor, A.R Fritzberg, S Kasina, L Hansen, J.F Sorensen, J Nucl Med 28 (1987) 1180 [12] D.S Edwards, E.H Cheesman, M.W Watson, L.J Maheu, S.A Nguyen, L Dimitre, T Nason, A.D Watson, R Walovitch, in: M Nicolini, G Bandoli, U Mazzi (Eds.), Technetium in Chemistry and Nuclear Medicine, vol 3, Cortina International, Verona, Italy, 1990, pp 433–444 [13] L Beyer, R Widera, Tetrahedron Lett 23 (1982) 1881 [24] [25] [26] [27] [28] L Beyer, J Hartung, R Widera, Tetrahedron 40 (1984) 405 H.H Nguyen, J Grewe, J Schroer, B Kuhn, U Abram, Inorg Chem 47 (2008) 5136 J Schroer, U Abram, Polyhedron 28 (2009) 2277 H.H Nguyen, P.I.d.S Maia, V.M Deflon, U Abram, Inorg Chem 48 (2009) 25 H.H Nguyen, J.J Jegathesh, P.I.d.S Maia, V.M Deflon, R Gust, S Bergemann, U Abram, Inorg Chem 48 (2009) 9356 P.I.d.S Maia, H.H Nguyen, D Ponader, A Hagenbach, S Bergemann, R Gust, V.M Deflon, U Abram, Inorg Chem 51 (2012) 1604 J.D Castillo Gomez, H.H Nguyen, A Hagenbach, U Abram, Polyhedron 43 (2012) 123 Synthesis of 2-aminoacetophenone-N-(4-methylthiosemicarbazone) The compound was synthesized from 2-aminoacetophenone and 4-methylthiosemicarbazone following a literature procedure [22] Yield 70% Elemental analysis: Calcd for C10H14N4S: C, 54.03; H, 6.35; N, 25.20; S, 14.42% Found: C, 54.20; H, 5.82; N, 24.39; S, 15.65%; IR (KBr, cm−1): 3237 (w), 2955 (w), 2900 (w), 1605 (vs), 1589 (vs), 1537 (m), 1480 (m), 1267 (s), 1110 (m), 1099 (m), 991 (m), 827 (m), 774 (s), 683 (s) 1H NMR (400 MHz, DMSO-d6, ppm): 2.30 (s, 3H, CH3), 3.00 (s, 3H, NCH3), 6.91 (t, J=7.0 Hz, 1H, C6H4), 7.01 (d, J=7.9 Hz, 1H, C6H4), 7.21 (t, J=7.3 Hz, 1H, C6H4), 7.44 (d, J=6.8 Hz, 1H, C6H4), 8.21 (s, br, 2H, NH), 10.20 (s, 1H, NH).Synthesis of H2L Solid N-[(diethylamino)(thiocarbonyl)]benzimidoyl chloride (1.018 g, mmol) was added to a mixture of 2-aminoacetophenone-N-(4-methylthiosemicarbazone) (889 mg, mmol) and triethylamine (1.01 g, 10 mmol) in 10 mL of absolute ethanol The mixture was stirred for h at 50 °C Upon cooling, H2L deposited as a yellow crystalline solid, which was filtered off, washed with cold MeOH and dried in vacuum Yield: 45% (616 mg) Elemental analysis: Calcd for C22H28N6S2: C, 59.97; H, 6.40; N, 19.07; S, 14.55% Found: C, 59.45; H, 6.02; N, 19.86; S, 15.02%; IR (KBr, cm−1): 3194 (m), 3051 (w), 2974 (m), 2928 (m), 2827 (w), 1717 (s), 1686 (s), 1608 (m), 1574 (s), 1539 (s), 1419 (s), 1335 (m), 1269 (s), 1246 (s), 1180 (m), 1134 (s), 1084 (m), 1026 (m), 898 (m), 759 (m), 694 (m) 1H NMR (400 MHz, CDCl3, ppm): 1.17 (t, J=7.1 Hz, 3H, CH3), 1.22 (t, J=7.1 Hz, 3H, CH3), 1.86 (s, 3H, CH3), 3.08 (s, 3H, NCH3), 3.75 (q, J=7.1 Hz, 2H, NCH2), 3.88 (q, J=7.1 Hz, 2H, NCH2), 7.07 (t, J=7.1 Hz, 2H, Ph), 7.13–7.19 (m, 4H, Ph+C6H4), 7.26 (m, 3H, Ph+C6H4), 7.64 (s, 1H, NH), 8.41 (s, 1H, NH), 12.63 (s, 1H, NH) 13C NMR (400 MHz, CDCl3, ppm): 11.99 (CH2CH3), 13.53 (CH2CH3), 15.55 (N_CCH3), 31.40 (NCH3), 44.92 (NCH2), 45.63 (NCH2), 125.45, 126.21, 128.08, 129.03, 129.11, 129.44, 130.49, 132.31, 135.28, 136.67 (aromatic), 145.52 (MeC_N), 159.77 (C_N), 178.36 (C_S), 184.95 (C_S) D.X West, A.A Nassar, F.A El-Saied, M.I Ayad, Trans Met Chem 24 (1999) 617 Synthesis of [ReN(L)] A mixture of H2L (44 mg, 0.1 mmol), [ReNCl2(PPh3)2] (80 mg, 0.1 mmol) and three drops of Et3N in CH2Cl2 (5 mL) was stirred for h at room temperature The solvent was removed to dryness and the residue was carefully washed with MeOH, dried in vacuum and redissolved in a CH2Cl2/MeOH (1:1) mixture Slow evaporation of the solvent gave red crystals Yield 75% (48 mg) Elemental analysis: Calcd for C22H26N7S2Re: C, 41.36; H, 4.10; N, 15.35; S, 10.04% Found: C, 41.11; H, 4.19; N, 14.95; S, 10.13%; IR (KBr, cm−1): 3417 (m), 3050 (w), 2970 (m), 2924 (m), 1527 (vs), 1440 (m), 1342 (s), 1257 (m), 1219 (m), 1149 (w), 1072 (m), 1033 (w), 810 (w), 764 (m), 671 (w) 1H NMR (400 MHz, CDCl3, ppm): 1.32 (t, J=7.2 Hz, 3H, CH3), 1.36 (t, J=7.2 Hz, 3H, CH3), 3.11 (d, J=5.0, 3H, NCH3), 3.13 (s, 3H, N=C-CH3), 3.58 (m, 1H, NCH2), 3.68 (m, 1H, NCH2), 4.32 (m, 1H, NCH2), 4.40 (m, 1H, NCH2), 5.28 (s, br, NH), 6.78 (d, J=8.0 Hz, 1H, C6H4), 6.93 (t, J=7.6 Hz, 1H, C6H4), 7.00 (t, J=7.7 Hz, 1H, C6H4), 7.10 (m, 3H, Ph), 7.27 (d, J=7.2 Hz, 2H, Ph), 7.75 (d, J=7.9 Hz, 1H, C6H4) FAB+ MS (m/z): 639, 90%, [M+H]+; 567, 12%, [M–NEt2 +H]+ H.H Nguyen, V.M Deflon, U Abram, Eur J Inorg Chem 21 (2009) 3179 Crystal data for [ReN(L)]: triclinic, space group P(−)1, a=8.598(1), b=10.974(1), c=13.669(1)Å, α=66.64(1), β=79.86(1), γ=77.99(1), V=1151.8(2)Å3, Z=2 STOE-IPDS, Mo Kα radiation (λ=0.71073 Å), T=200 K, 21,421 reflections measured, 5839 independent, 289 parameters, μ=5.482 mm−1, absorption correction: integration, Tmin =0.2036, Tmax =0.3541 Structure solution and refinement: SHELXS-97, SHELXL-97 [26], R1=0.0357, wR2=0.0978, GooF=1.157, CCDC deposit number: CCDC-898325 G.M Sheldrick, SHELXS-97 and SHELXS-97 — a Programme Package for the Solution and Refinement of Crystal Structures, University of Göttingen, Germany, 1997 K Brandenburg, H Putz, Diamond — a Crystal and Molecular Structure Visualisation Software, , 2005 Bonn, Germany Synthesis of [TcN(L)] and [TcN(PPh3){Et2NC(S)NH}(L′)] Solid [TcNCl2(PPh3)2] (70 mg, 0.1 mmol) was added to a stirred solution of H2L (44 mg, 0.1 mmol) in 76 H.H Nguyen et al / Inorganic Chemistry Communications 26 (2012) 72–76 CH2Cl2 (5 mL) After adding drops of Et3N, the mixture was stirred for additional 15 at room temperature This resulted in a complete dissolution of [TcNCl2(PPh3)2] and the formation of a red solution The solvent was removed under vacuum, and the residue was recrystallized from a CH2Cl2/MeOH mixture to obtain large orange-red crystals of [TcN(L)] and yellow needles of [TcN(PPh3) {Et2NC(S)NH}((L′)] which were separated mechanically.Data for [TcN(L)]: Yield 40% (21 mg) Elemental analysis: Calcd for C22H26N7S2Tc: Tc, 17.9% Found: Tc, 18.1%; IR (KBr, cm−1): 3418 (m), 3051 (w), 2970 (m), 2924 (m), 1547 (s), 1528 (vs), 1477 (m), 1431 (m), 1357m), 1338 (m), 1261 (m), 1226 (m), 1145 (w), 1091 (w), 1064 (m), 1037 (w), 810 (w), 756 (m), 675 (w) 1H NMR (400 MHz, CDCl3, ppm): 1.34 (m, 6H, CH3), 2.97 (s, 3H, N_C-CH3), 3.05 (d, J = 4.8, 3H, NCH3), 3.54 (m, 1H, NCH2), 3.66 (m, 1H, NCH2), 4.19 (m, 1H, NCH2), 4.26 (m, 1H, NCH2), 5.15 (s, br, NH), 6.67 (d, J = 7.9 Hz, 1H, C6H4), 6.89 (t, J = 7.4 Hz, 1H, C6H4), 6.95 (t, J = 7.6 Hz, 1H, C6H4), 7.10(m, 3H, Ph), 7.28 (d, J = 7.1 Hz, 2H, Ph), 7.66 (d, J = 7.9 Hz, 1H, C6H4).Data for [TcN(PPh3) {Et2NC(S)NH}(L′)]: Yield 14% (12 mg) Elemental analysis: Calcd for C40H41N7PS2Tc: Tc, 12.2% Found: Tc, 12.4% IR (KBr, cm−1): 3363 (m), 3044 (w), 2978 (m), 2931 (m), 1558 (vs), 1473 (m), 1434 (m), 1307 (s), 1269 (s), 1238 (s), 1184 (m), 1149 (w), 1095 (m), 1068 (m), 860 (w), 740 (s), 694 (s), 528 (m), 497 (m) 1H NMR (400 MHz, CDCl3, ppm): 0.49 (t, J = 7.1 Hz, 3H, CH3), 0.88 (t, J = 7.1 Hz, 3H, CH3), 1.41 (s, 3H, N=C\CH3), 2.25 (m, 1H, NCH2), 2.39 (m, 1H, NCH2), 3.12 (m, 2H, NCH2), 3.66 (s, 3H, NCH3), 5.76 (s, br, 1H, NH), 7.32 (m, 17H, Ph), 7.60 (m, 6H, Ph), 8.05 (d, J = 7.7 Hz, 1H, Ph) 31P NMR (400 MHz, CDCl3, ppm): 48.86 (s) [29] Crystal data for [TcN(L)]: triclinic, space group P(−)1, a=8.577(1), b=10.974(1), c=13.672(1) Å, α=66.82(1), β=80.34(1), γ=78.64(1), V=1154.0(2)Å3, Z=2 STOE-IPDS, Mo Kα radiation (λ=0.71073 Å), T=200 K, 11967 reflections measured, 6149 independent, 290 parameters, μ=0.830 mm−1, absorption correction: none Structure solution and refinement: SHELXS-97, SHELXL-97 [26], R1=0.0580, wR2=0.0998, GooF=0.902, CCDC deposit number: CCDC-898326 [30] F Tisato, U Mazzi, G Bandoli, G Cros, M.-H Darbieu, Y Coulais, R Guiraud, J Chem Soc., Dalton Trans (1991) 1301 [31] G Cros, H.B Tahar, D de Montauzon, A Gleizes, Y Coulais, R Guiraud, E Bellande, R Pasqualini, Inorg Chim Acta 227 (1994) 25 [32] Crystal data for [TcN(PPh3){Et2NC(S)NH}(L′)]× H2O: triclinic, space group P(−)1, a = 11.622(3), b = 13.182(3), c = 14.620(4) Å, α = 92.45(2), β = 92.73(2), γ = 110.76(2), V = 2087.5(9) Å3, Z = STOE-IPDS, Mo Kα radiation (λ = 0.71073 Å), T= 200 K, 21,440 reflections measured, 11,079 independent, 465 parameters, μ = 0.522 mm−1, absorption correction: none Structure solution and refinement: SHELXS-97, SHELXL-97 [26], R1 = 0.074, wR2 = 0.1682, GooF = 0.865, CCDC deposit number: CCDC-898327 [33] Selected bond lengths and angles in [TcN(PPh3){Et2NC(S)NH}(L′)]: Tc–N1 1.617(8), Tc–S1 2.403(3), Tc–N3 2.097(7), Tc–S12 2.373(2), Tc–P 2.405(2), S1– C2 1.767, S12–C11 1.742(9), C2–N3 1.32(1), C2–N6 1.33(1), C4–N5 1.33(1), C4–N9 1.34(1), N10–C11 1.32(1), C11–N13 1.39(1), C7–N13 1.48(1), C7–N9 1.47(1); N1–Tc–S1 111.6(3), N1–Tc–N3 107.1(4), N1–Tc–S12 111.6, N1–Tc–P 94.9(3), N3–Tc–P 156.4(2), S1–Tc–S12 136.2(1) ... atom is best described as a distorted square pyramid with an apical nitrido ligand The basal plane contains three ligands: the heterocyclic thiolato ligand {L′} −, which binds monodentate via... confirms the analogous arrangement of the ligands [29] The technetium atom also reveals a distorted square-pyramidal coordination sphere with an apical {N}3− ligand Since the molecular structures... sulfur atom, a bidentate N,N-diethylthioureido ligand and PPh3, which is arranged in a trans position to the nitrogen donor atom The bonding situation in the ligand {L′} − reveals the sp hybridization