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Cite This: Inorg. Chem. 2019, 58, 7925−7930
The Formation of Rhenium(V) Complexes with Dihydroxyphosphoranes and Diarylphosphinic Acid Derivatives Generated from Tris(1,2,3-triazolyl)phosphine Oxides Bo Li, Adelheid Hagenbach, and Ulrich Abram* Freie Universität Berlin, Institute of Chemistry and Biochemistry, Fabeckstr. 34/36, D-14195 Berlin, Germany
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S Supporting Information *
ABSTRACT: Tris(1-phenyl-1H-1,2,3-triazol-4-yl)phosphine oxide (OP(1,2,3Tz1‑Ph)3) and tris(1-benzyl-1H-1,2,3-triazol-4yl)phosphine oxide (OP(1,2,3Tz1‑benz)3) react with (NBu4)[ReOCl4] under partial hydrolysis and formation of rhenium(V) complexes with unprecedented dihydroxyphosphoranato or diarylphosphinato ligands. Anionic, binuclear complexes of the compositions [Cl3(O)Re{O2P(1,2,3Tz1‑Ph)3}Re(O)Cl2]− and [Cl3(O)Re{O2P(1,2,3Tz1‑benz)3}Re(O)Cl2]− are formed as the result of a first hydrolysis step of the phosphine oxides, which has been proven by an experiment with H218O. Two more metal-containing products of these reactions, [ReOCl 3 {O 2 P( 1 , 2 , 3 Tz 1 ‑P h ) 2 }] − and [Cl 3 (O)Re{O 2 P(1,2,3Tz1‑benz)2}Re(O)Cl3]−, could also be isolated and studied by X-ray diffraction. Their structures confirm a metal-mediated P−C bond cleavage and the formation of arylphosphinic acids, which finally act as ligands in the products.
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INTRODUCTION The coordination chemistry of tris(azolyl)phosphines and their oxides has been dominated for a long time by the corresponding imidazolyl derivatives, which have been used as histidine mimics in models of bioinorganic chemistry. A comprehensive review covering all these aspects has been published recently.1 Relatively little is known about corresponding pyrazolyl and triazolyl derivatives. Some tris(1,2,4triazolyl)phosphine derivatives are used for triazolylation and phosphorylation reactions. Particularly, the corresponding phosphine oxides have been found to be useful synthons for the synthesis of nucleosides.2−7 Exploration of the chemistry of tris(1,2,3-triazolyl)phosphines started in 2008, when Lammertsma et al. synthesized tris(1-phenyl-1H-1,2,3-triazol-4yl)phosphine oxide, OP(1,2,3Tz1‑Ph)3, by a Cu(I)-catalyzed Huisgen cycloaddition.8 The compound can act as a tripodal ligand via three nitrogen donor atoms, as has been shown with the synthesis of a corresponding Rh(III) complex, but also, other coordination modes have been found.9−11 Reduction of OP(1,2,3Tz1‑Ph)3 with PhSiH3, or an alternative one-pot synthesis starting with a [2 + 3] cycloaddition of an alkynyl Grignard reagent, gives the related phosphine P(1,2,3Tz1‑Ph)3, which has also been demonstrated to be a versatile ligand with variable denticity in Zn(II) complexes and heterobimetallic units.8,12 In the present study, we report information on the reactions of oxidorhenium(V) complexes with OP(1,2,3Tz1‑Ph)3 and OP(1,2,3Tz1‑benz)3 (see Chart 1) and their unexpected and unprecedented products. © 2019 American Chemical Society
Chart 1. Potentially Tripodal Ligands Used in This Paper
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EXPERIMENTAL SECTION
Materials. All chemicals were reagent grade and used without further purification. [ReOCl3(PPh3)2] and (Bu4N)[ReOCl4] were synthesized by literature procedures.13,14 The syntheses of TMS-C C-MgBr, triethynylphosphine oxide, OP(1,2,3Tz1‑Ph)3, and benzylazide have been prepared as reported elsewhere.8,15,16 Physical Measurements. IR spectra were obtained on a Nicolet iS10 FT-IR spectrometer. The NMR spectra were recorded at 298 K on a JEOL 400 MHz spectrometer and referenced internally to solvent resonances. ESI-MS data were measured on an Agilent 6210 ESI−TOF, Agilent Technologies. Elemental analyses (CHN) were performed on a Heraeus Vario EL elemental analyzer from Elementar Analysensysteme GmbH. Received: March 4, 2019 Published: June 4, 2019 7925
DOI: 10.1021/acs.inorgchem.9b00635 Inorg. Chem. 2019, 58, 7925−7930
Article
Inorganic Chemistry Table 1. Crystallographic Data and Information about the Structure Determinations formula Mw (g mol−1) crystal system a (Å) b (Å) c (Å) α (deg) β (deg) γ (deg) V/Å3 space group Z Dcalc (g cm−3) no. reflect. no. indep. Rint no. param. R1/wR2 GOF CCDC
1 · 2CH2Cl2
2
3 · CH2Cl2
4
C42H58Cl9N10O4PRe2 1489.40 monoclinic 23.159(1) 19.570(1) 24.909(1) 90 99.78(1) 90 11125.2 P21/n 8 1.778 22738 1218 0.058 1218 0.058/0.067 1.052 1895695
C32H48Cl3N7O3PRe 902.29 triclinic 11.020(1) 12.780(1) 14.670(2) 77.12(4) 76.52(4) 70.80(4) 1873.0(4) P1̅ 2 1.600 93103 7697 0.0204 477 0.0204/0.0482 1.084 1895692
C44H62Cl7N10O4PRe2 1446.55 orthorhombic 15.972(1) 21.959(2) 31.445(2) 90 90 90 11028.5(1) P212121 8 1.742 24451 1220 0.0204 1220 0.0204/0.0504 1.035 1895694
C34H52Cl6N7O4PRe2 1238.89 monoclinic 15.032(2) 17.490(2) 17.121(2) 90 99.052(4) 90 4445.3 P21/c 4 1.851 11100 487 0.0274 487 0.0274/0.0485 1.033 1895693
X-Ray Crystallography. The intensities for the X-ray determinations were collected on a Bruker D8 Venture CCD instrument with Mo/Kα radiation (λ = 0.71073 Å). The structure solutions and refinements were performed with the SHELX program package.17 Hydrogen atoms were calculated for idealized positions and treated with the “riding model” option of SHELXL. Details about crystal data and structure determination parameters are given in Table 1. Additional information about the structure calculations has been deposited with the Cambridge Crystallographic Data Centre. Syntheses. Tris(1-benzyl-1H-1,2,3-triazol-4-yl)phosphine Oxide (OP(1,2,3Tz1‑benz)3). Benzylazide (3.33 g, 25 mmol), tris(ethynyl)phosphine oxide (1 g, 8.33 mmol), and CuSO4(64 mg, 0.4 mmol) were dissolved in a mixture of acetonitrile (2 mL) and water (0.5 mL). Sodium ascorbate (150 mg, 0.8 mmol) was added in small portions. The mixture was stirred for 24 h at room temperature, and then extraction was performed with CHCl3 (3 × 20 mL). The combined organic extracts were dried over MgSO4, and all solids were removed by filtration over Celite. The Celite plug was washed with CHCl3 (3 × 10 mL), and all volatiles were evaporated. The product was purified by recrystallization from hexane. Yield: 95%. Elemental analysis calcd for C27H24N9OP · 1/2 CHCl3: C, 56.8; H, 4.3; N, 21.7%. Found: C, 56.8; H, 4.9; N, 21.1%. 1H NMR (CD2Cl2, ppm): 8.14 (s, 3H, CCH), 7.26−7.35 (m, 15H, Ph-H), 5.54 (m, 6H, PhCH2). 31P NMR (CDCl3): −5.8 ppm. MS (ESI+): [M + Na]+ m/z = 544.1744, calcd 544.1739; [M + K]+ m/z = 560.1488, calcd 560.1478. IR (cm−1): 3120, 2961, 1773, 1497, 1456, 1259, 1220, 1079, 1013, 863, 792, 720, 662. (Bu4 N)[Cl 3(O)Re{O 2P( 1,2,3 Tz 1‑Ph ) 3}Re(O)Cl 2] (1) and (Bu 4N)[ReOCl3{O2P(1,2,3Tz1‑Ph)2}] (2). OP(1,2,3Tz1‑Ph)3 (48 mg, 0.1 mmol) was dissolved in 2 mL of CH2Cl2, and (Bu4N)[ReOCl4] (116 mg, 0.2 mmol) was added. The mixture was stirred for 5 min at room temperature, during which time its color turned green. Diethyl ether (20 mL) was added, which resulted in the formation of a green precipitate. This solid was filtered off and dried in vacuo. It was dissolved in 2 mL of dichloromethane, and n-hexane (0.5 mL) was added. Green crystals of compound 1 deposited during slow evaporation of the solvent to a volume of about 1 mL. They were filtered off, and the residual solution was brought to dryness, which resulted in the formation of a sticky, blue-green resin. Repeated dissolution of this material in CH2Cl2 and treatment with n-hexane finally gave the light green crystals of compound 2. Yields: 36 mg (24%) for compound 1 and 22 mg (24%) for compound 2. Compound 1. Elemental analysis calcd for C40H54Cl5N10O4PRe2: C, 36.4; H, 4.1; N, 10.6%. Found: C, 36.9; H, 4.4; N, 10.5%. 1H NMR
(CDCl3, ppm): 8.94 (s, 2H, CCH), 8.66 (s, 1H, CCH), 7.70−7.75 (m, 6H, Ph-H), 7.43−7.58 (m, 8H, Ph-H), 3.20−3.24 (m, 8H, NCH2), 1.63 (m, 8H, CH2), 1.45−1.48 (m, 8H, CH2), 0.98−1.01 (m, 12H, CH3). 31P NMR (CDCl3): −61.7 ppm. IR (cm−1): 3108, 2959, 2931, 2871, 1595, 1498, 1464, 1379, 1304, 1271, 1217, 1170, 1071, 1039, 987, 973, 913, 880, 788, 772, 756, 729, 713, 702, 681, 644, 612, 599, 573. MS (ESI−): [C24H18Cl5N9O4PRe2]− m/z = 1075.8801; calcd, 1075.8777. Compound 2. Elemental analysis calcd for C32H48Cl3N7O3PRe: C, 42.6; H, 5.4; N, 10.6%. Found: C, 43.6; H, 5.4; N, 10.8%. 1H NMR (CDCl3, ppm): 8.66 (s, 1H, CCH), 8.56 (s, 1H, CCH), 7.43−7.73 (m, 10H, Ph-H), 3.12−3.16 (m, 8H, NCH2), 1.60− 1.65 (m, 8H, CH2), 1.34−1.43 (m, 8H, CH2), 0.94−0.99 (t, 9H, CH3). 31P NMR (CDCl3): 1.8 ppm. IR (cm−1): 2962, 2932, 2875, 1596, 1504, 1482, 1465, 1381, 1300, 1257, 1137, 1083, 1017, 989, 950, 908, 878, 791, 761, 707, 689, 660, 615, 604, 570. MS (ESI−): [C16H12Cl3N6O3PRe]− m/z = 658.9271; calcd, 658.9332. (NBu4)[Cl3(O)Re{O2P(1,2,3Tz1‑benz)3}Re(O)Cl2] (3). OP(1,2,3Tz1‑benz)3 (52 mg, 0.1 mmol) was dissolved in 2 mL of CH2Cl2. (Bu4N)[ReOCl4] (116 mg, 0.2 mmol) was added, and the mixture was stirred for 5 min. The solution turned green. Diethyl ether (20 mL) was added, which resulted in the dissolution of unreacted OP(1,2,3Tz1‑benz)3 and the formation of a blue-green precipitate. The solid was filtered off and dried in vacuo. Single crystals were obtained by recrystallization from CH2Cl2/n-hexane. Yield: 27 mg (20%). Elemental analysis calcd for C43H60Cl5N10O4PRe2: C, 37.9; H, 4.5; N, 10.3%. Found: C, 38.0; H, 4.5; N, 10.3%. 1H NMR (CDCl3, ppm): 8.36 (s, 2H, CCH), 8.01 (s, 1H, CCH), 7.30−7.37 (m, 18H, Ph-H), 5.71 (s, 2H, PhCH2), 5.63 (s, 4H, PhCH2), 3.06−3.10 (m, 8H, NCH2), 1.54−1.61 (m, 8H, CH2), 1.37−1.43 (m, 8H, CH2), 0.97−1.24 (m, 12H, CH3). 31P NMR (CDCl3): −62.0 ppm. IR (cm−1): 3129, 2961, 2875, 1512, 1497,1481, 1457, 1381, 1297, 1262, 1208, 1112, 1079, 1027, 990, 976, 800, 782, 728, 695, 680, 666, 644, 602, 569. MS (ESI−): [C27H24Cl5N9O4PRe2]− m/z = 1117.9144; calcd, 1117.9252. (Bu4N)[Cl3(O)Re{O2P(1,2,3Tz1‑benz)2}Re(O)Cl3] (4). OP(1,2,3Tz1‑benz)3 (52 mg, 0.1 mmol) and (Bu4N)[ReOCl4] (116 mg, 0.2 mmol) were placed in a Schlenk tube. CH2Cl2 (5 mL) was added, which gave a green solution. This solution was overlayered with 5 mL of nhexane. A light green resin and some green crystals were formed upon standing for 5 days. Single crystals for X-ray diffraction were obtained by recrystallization from acetone/CHCl3 on air. Yield: 65 mg (50%). Elemental analysis calcd for C34H52Cl6N7O4PRe2: C, 33.0; H, 4.2; N, 7.91%. Found: C, 34.0; H, 4.4; N, 8.23%. 1H NMR (acetone-d6, 7926
DOI: 10.1021/acs.inorgchem.9b00635 Inorg. Chem. 2019, 58, 7925−7930
Article
Inorganic Chemistry Scheme 1. Reactions of (NBu4)[ReOCl4] with OP(1,2,3Tz1‑Ph)3 and OP(1,2,3Tz1‑benz)3
ppm): 8.76 (s, 2H, CCH), 7.55−7.57 (m, 4H, Ph-H), 7.41−7.45 (m, 6H, Ph-H), 6.19 (s, 4H, PhCH2), 3.39−3.41 (m, 8H, N CH2), 1.77−1.80 (m, 8H, CH2), 1.37−1.41 (m, 8H, CH2), 0.93−0.95 (m, 12H, CH3). 31P NMR (CDCl3): 14.1 ppm. IR (cm−1): 3135, 2963, 2874, 1517, 1489, 1470, 1459, 1382, 1360, 1290, 1255, 1157, 1112, 1085, 1047, 1035, 1019, 999, 879, 794, 719, 707, 660, 621, 605, 567. MS (ESI−): [C18H16Cl6N6O4PRe2]− m/z = 996.8107; calcd, 996.8187. Compound 4 can also be isolated from the filtrate of the synthesis of compound 3, which is obtained after the filtration of the blue-green precipitate, and a workup as described for complex 2. The yield of this procedure, however, is clearly lower.
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RESULTS AND DISCUSSION The sparingly soluble [ReOCl3(PPh3)2], which is frequently used as a suitable starting material for the synthesis of oxidorhenium(V) complexes via ligand exchange procedures, reacts with the potentially tridentate ligands of Chart 1 in various solvents under dissolution and final formation of dark brown mixtures. However, no defined products could be isolated. 31P NMR spectra of such solutions give evidence for the formation of a variety of phosphorus-containing species with chemical shifts between +30 and −12 ppm. The number and intensities of the signals vary depending on the solvent used and the reaction time. Reactions of OP(1,2,3Tz1‑Ph)3 or OP(1,2,3Tz1‑Ph)3 with (NBu4)[ReOCl4] in CH2Cl2 are more clear but deliver unexpected products with unprecedented compositions. A summary of the products is shown in Scheme 1. With both ligands, blue-green solutions are rapidly formed, from which blue, crystalline compounds could be isolated upon concentrating and treating the reaction mixtures with n-hexane. These products (complexes 1 and 3) are binuclear rhenium(V) complexes, which each contain one central dihydroxyphosphorane ligand being formed by hydrolysis of the respective tris(1,2,3-triazolyl)phosphine oxides. This ligand connects the two rhenium ions by the formation of an O,N,N-chelate to one and an O,N-chelate to the other oxidorhenium(V) unit. The coordination spheres of the metal ions are completed by two and three chlorido ligands, respectively. Figure 1 shows ellipsoid representations of the molecular structures of the anions of compounds 1 and 3. Selected bond lengths and angles are summarized in Table 2. The two rhenium atoms in these complexes are six-coordinate with each one oxygen atom of the dihydroxyphosphoranato ligand in the trans position to the oxido oxygen atoms. The central phosphorus atom is clearly trigonal bipyramidal with the oxygen atoms occupying the axial positions. The P−O bond
Figure 1. Ellipsoid representations of the complex anions of compounds 1 and 3. Thermal ellipsoids represent 50% probability. Hydrogen atoms have been omitted for the sake of clarity.
lengths between 1.623(3) and 1.712(3) Å are in a range between single and double bonds, which corresponds with the interpretation of this unit as a phosphoranate derivative. The IR spectra confirm the presence of the ReO double bonds with two medium bands at 973 and 987 cm−1 for 1 and at 976 and 990 cm−1 for compound 3, while the 31P NMR spectroscopy gives clear evidence for the observed changes at the central phosphorus atoms. The signals of OP(1,2,3Tz1‑Ph)3 (−5.7 ppm) and OP(1,2,3Tz1‑benz)3 (−5.8 ppm) disappear and new signals appear at −61.7 ppm for complex 1 and −62.0 7927
DOI: 10.1021/acs.inorgchem.9b00635 Inorg. Chem. 2019, 58, 7925−7930
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Inorganic Chemistry Table 2. Selected Bond Lengthsa and Anglesb in 1 and 3c Re1−O1 Re2−O4 Re1−O2 Re2−O3 P1−O2 P1−O3 O2−P1−O3 C11−P1−C19 C11−P1−C17 C19−P1−C17
1
3
1.684(3)/1.698(3) 1.699(3)/1.690(3) 1.977(3)/1.933(3) 1.992(3)/1.960(3) 1.632(3)/1.647(3) 1.712(3)/1.701(3) 178.6(2)/179.1(2) 104.0(2)/105.9(2) 127.3(2)/126.0(2) 127.3(2)/127.8(2)
1.699(3)/1.686(3) 1.684(3)/1.682(4) 1.919(3)/1.927(3) 1.967(3)/1.967(3) 1.623(3)/1.621(3) 1.710(3)/1.708(3) 177.6(2)/177.3(2) 105.6(2)/105.8(2) 126.7(2)/126.3(2) 127.0(2)/127.1(2)
a
Unit in angstroms (Å). bUnit in degrees (°). cValues are given for each two independent species.
ppm for complex 3. These values are in good agreement with the resonances observed for similar “organic” oxyphosphoranes such as Ph 3 P(OEt) 2 (−55 ppm) or Ph 3 P(OCH 2 R F ) 2 derivatives with RF various fluorinated substituents (−55.5 to −57.7 ppm).18,19 The formation of phosphorane-like compounds from OP(1,2,3Tz1‑Ph)3 and OP(1,2,3Tz1‑benz)3 is unexpected and generally unprecedented for phosphine oxides. Such pentacoordinated phosphorus compounds are commonly formed by oxidative procedures starting from the corresponding phosphine building blocks as has also been reported for Ph3P(OEt)2 or Ph3P(OCH2C2F5)2.18,19 In the present case, a (metal-supported) hydrolytic pathway with residual water in the solvent CH2Cl2 is probable. Attempts to produce the hydroxyphosphoranes by heating pure OP(1,2,3Tz1‑Ph)3 in moist CH2Cl2, however, gave no evidence for such hydrolysis, while after the addition of (NBu4)[ReOCl4], two 31P NMR signals in the region of −60 ppm appeared. The origin of the incoming oxygen atom could be identified unambiguously by a labeling experiment. For this, carefully dried CH2Cl2 was saturated with H218O (99% isotope enrichment) and subsequently used as the solvent for a reaction between (NBu4)[ReOCl4] and OP(1,2,3Tz1‑benz)3. The ESI−mass spectrum of the product clearly shows a shift of the complete isotope pattern of the molecular ion of the complex anion by two mass numbers (Figure 2). The mechanism of the observed hydrolysis of OP(1,2,3Tz1‑Ph)3 and OP(1,2,3Tz1‑benz)3 is so far not completely clear but seems to start with the coordination of the oxygen atoms of the phosphine oxides to the vacant sixth coordination position of a [ReOCl4]− anion with subsequent coordination of one triazole unit to the same rhenium atom. The attack of residual water in the solvent CH2Cl2 on the activated phosphorus atom forms the five-coordinate dioxyphosphorane unit, which finally binds to a second rhenium atom in facial mode. The resulting dinuclear complexes deposit from a CH2Cl2/n-hexane mixture as blue crystals. No defined products could be isolated from attempted reactions in absolutely dry solvents. Compounds 1 and 3 are stable as solids but undergo a marked decomposition in solution. The degree of the decomposition can be followed by subsequent measurements of 31P NMR spectra of the reaction mixture. The recorded spectra show that the degradation is rapid in polar solvents such as methanol or acetone and much slower in dichloromethane or chloroform. The detection of various signals depending on the solvents indicates a complex course of the decomposition. Finally, the oxidation of the metal is also
Figure 2. Molecular ion region of the ESI−mass spectrum of compound 3, synthesized in “normal” CH2Cl2 (a) and in H218Osaturated solvent (b).
indicated by the isolation of considerable amounts of (NBu4)ReO4. Two of the decomposition products could be isolated, which gives evidence that phosphorus−carbon bonds are broken. Blue crystals of rhenium(V) complexes with diarylphosphinic acid ligands were isolated in similar yields to that of the phosphoranato complexes from the residual reactions mixtures of the syntheses of 1 and 3. For compound 4, a separate synthetic procedure with a better yield is described in the Experimental Section. Compound 2 is a mononuclear complex with an O,Nbonded bis(1-phenyl-1H-1,2,3-triazol-4-yl)phosphinic acid ligand. The second triazole ring remains uncoordinated. Figure 3 shows an ellipsoid plot of the compound. The rhenium atom is six-coordinate with the two oxygen atoms trans to each other. Distortions in the tetrahedral environment (angles 7928
DOI: 10.1021/acs.inorgchem.9b00635 Inorg. Chem. 2019, 58, 7925−7930
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Inorganic Chemistry
The 31P NMR signal of 4 appears at 14.1 ppm, which is downfield shifted with respect to the signal of compound 2. This can be understood as a consequence of the formation of two chelate rings, which results in a lower distortion of the tetrahedral environment of the phosphorus atom. The ReO band in the IR spectrum is observed at 999 cm−1, which is in the normal range of six-coordinate complexes.20
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CONCLUSIONS Summarizing, it can be stated that reactions of the common rhenium(V) precursor (NBu4)[ReOCl4] with the tris(azolyl)phosphine oxides OP(1,2,3Tz1‑Ph)3 or OP(1,2,3Tz1‑benz)3 do not give the expected scorpionate-like complexes but result in partial hydrolytic degradation of the phosphorus compounds and the formation of unprecedented oxyphosphoranato and phosphinato complexes of rhenium(V). Further studies are required to understand the mechanism of this metal− supported degradation of phosphine oxides.
Figure 3. Ellipsoid representation of the complex anion of compound 2. Thermal ellipsoids represent 50% probability. Hydrogen atoms have been omitted for clarity. Selected bond lengths (Å) and angles (°): Re1−O2, 1.671(2); Re1−O3, 2.069(2); Re1−N11, 2.132(2); P1−O3, 1.536(2); P1−O1, 1.476(2); O1−P1−O3, 121.2(1); O1− P1−C12, 112.6(1); O1−P1−C21, 111.1(2); O3−P1−C12, 98.1(1); O3−P1−C21, 104.7(1); C12−P1−C21, 107.9(1).
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ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.inorgchem.9b00635.
between 98.1(1)° and 121.2(1)°) of the phosphorus atom are mainly due to the formation of the chelate ring. The infrared spectrum of 2 shows the ReO vibration at 950 cm−1 and the PO band at 1257 cm−1. A resonance at 1.8 ppm is observed in the 31P NMR spectrum of the complex. A binuclear complex with the corresponding bis(1-benzyl1H-1,2,3-triazol-4-yl)phosphinic acid ligand (compound 4) has been formed as a second hydrolysis product during the reaction between (NBu4)[ReOCl4] and OP(1,2,3Tz1‑benz)3. An ellipsoid representation of the structure of the complex anion is shown in Figure 4. In this complex, the two “nonbinding” nitrogen and oxygen atoms of complex 2 coordinate a second {ReOCl3} unit. The bonding features around the two rhenium atoms of complex 4 are unexceptional and resemble the situation in compound 2.
Tables containing more structural parameters and full ellipsoid representations (PDF) Accession Codes
CCDC 1895692−1895695 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing
[email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
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AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. ORCID
Ulrich Abram: 0000-0002-1747-7927 Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS We gratefully acknowledge the Ph.D. scholarship given to L.B. from the Chinese Scholarship Council (CSC). REFERENCES
(1) Tazelaar, C. G. J.; Slootweg, J. C.; Lammertsma, K. Coordination chemistry of tris(azolyl) phosphines. Coord. Chem. Rev. 2018, 356, 115−126. (2) Kraszewski, A.; Stawinski, J. Phosphoryl tris-triazole - a new phosphorylating reagent. Tetrahedron Lett. 1980, 21, 2935−2936. (3) Froehler, B. C.; Ng, P. G.; Matteucci, M. D. Synthesis of DNA via deoxynucleoside H-phosphonate intermediates. Nucleic Acids Res. 1986, 14, 5399−5407. (4) Pongracz, K.; Kaur, S.; Burlingame, A. L.; Bodell, W. J. O6substituted-2’-deoxyguanosine-3′-phosphate adducts, detected by 32P post-labeling of styrene oxide treated DNA. Carcinogenesis 1989, 10, 1009−1013. (5) Hovinen, J.; Azhayeva, E.; Azhayev, A.; Guzaev, A.; Lönberg, H. Synthesis of 3′-O-(–Aminoalkoxymethyl)thymidine 5′-Triphosphates,
Figure 4. Ellipsoid representation of the complex anion of compound 4. Thermal ellipsoids represent 50% probability. Hydrogen atoms have been omitted for clarity. Selected bond lengths (Å) and angles (°): Re1−O11, 1.660(2); Re1−O12, 2.140(2); Re1−N11, 2.132(3); Re2−O21, 1.663(2); Re2−O22, 2.171(2); Re2−N21, 2.128(3); P1− O12, 1.509(2); P1−O22, 1.507(2); O12−P1−O22, 117.9(1); O12− P1−C11, 100.6(1); O12−P1−C21, 112.4(1); O22−P1−C11, 114.8(1); O22−P1−C21, 100.6(1); C11−P1−C21, 111.0(2). 7929
DOI: 10.1021/acs.inorgchem.9b00635 Inorg. Chem. 2019, 58, 7925−7930
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DOI: 10.1021/acs.inorgchem.9b00635 Inorg. Chem. 2019, 58, 7925−7930
