X-ray and Spectroscopy Studies of Mercury (II) and Silver (I) Complexes of α-Ketostabilized Phosphorus Ylides

α-케토안정화된 일리드화 인의 수은(II) 및 은(I) 착물에 대한 X-선 및 분광학적 연구

Abstract

The complexation behavior of the $\alpha$-ketostabilized phosphorus ylides $Ph_3P$=CHC(O) $C_6H_4-X$ (X=Br, Ph) towards the transition metal ions mercury (II) and Silver (I) was investigated. The mercury(II) complex {$HgX_2$ [Y]} 2 ($Y_1$=4-bromo benzoyl methylene triphenyl phosphorane; X=Cl(1), Br(2), I(3), $Y_2$=4-phenyl benzoyl methylene triphenyl phosphorane; X=Cl(4), Br(5), I(6)) have been prepared from the reaction of $Y_1$ and $Y_2$ with $HgX_2$ (X=Cl, Br, I) respectively. Silver complexes [$Ag(Y_2)_2]$ X(X=$BF_4$(7), OTf(8)) of the $\alpha$-keto-stabilized phosphorus ylides ($Y_2$) were obtained by reacting this ylide with AgX (X=$BF_4$, OTf) in $Me_2CO$. The crystal structure of complexes (1) and (4) was discussed. These reactions led to binuclear complexes C-coordination of ylide and trans-like structure of complexes $[Y_1HgCl_2]_2$. $CHCl_3$ (1) and $[Y_2HgCl_2]_2$ (4) is demonstrated by single crystal X-ray analyses. Not only all of complexes have been studied by IR, $^1H$ and $^{31}P$ NMR spectroscopy, but also complexes 1-3 have been characterized by $^{13}$CNMR.

전이금속 이온인 수은(II) 및 은(I)에 대한 $\alpha$-케토안정화된 일리드화 인 $Ph_3P$=CHC(O) $C_6H_4$-X (X=Br, Ph)의 착물 반응 행동을 연구하였다. 수은(II) 착물 {$HgX_2$ [Y]} 2 ($Y_1$=4-bromo benzoyl methylene triphenyl phosphorane; X=Cl(1), Br(2), I(3), $Y_2$=4-phenyl benzoyl methylene triphenyl phosphorane; X=Cl(4), Br(5), I(6))는 $Y_1$ 및 $Y_2$를 $HgX_2$ (X=Cl, Br, I)와 각각 반응시켜 제조하였다. $\alpha$-케토안정화된 일리드화 인($Y_2$)의 은(I) 착물 [Ag$(Y_2)_2$] X(X=$BF_4$(7), OTf(8))는 이러한 일리드와 AgX(X=$BF_4$, OTf)를 아세톤에서 반응시켜 얻었다. 착물 (1)과 (4)의 결정구조를 고찰하였다. 일리드의 C-배위 이핵착물과 트랜스-구조의 착물$[Y_1HgCl_2]_2$. $CHCl_3$ (1) 및 $[Y_2HgCl_2]_2$ (4)를 형성하는 이들 반응에 대해 단결정 X-선 분석을 통해 고찰하였다. 모든 착물(1-3)은 IR, $^1H$ 및 $^{31}P$ NMR 뿐만아니라 $^{13}$CNMR을 통하여 확인하였다.

INTRODUCTION

α-ketostabilized phosphorus ylides are versatile ligands for heavy metal ions1-5 and interesting ligands in organometallic chemistry and useful intermediates for organic synthesis.6-19 They are versatile ligands for catalysts in a very small number of catalytic reactions such as, for example, the hydrogenation of olefins20 and the cyclotrimerization21 and polymerization of acetylenes,22 but the most important application is in the industrially used SHOP process. 23 The α-keto-stabilized phosphorus ylides are distinguishable from no stabilized ylides, since they can be easily handled due to an additional stabilization from delocalization of the negative charge. The α-keto-stabilized phosphorus ylides was shown interesting properties such as their high stability and their ambidentate character as ligands (C- versus O-coordination).24-30 This ambidentate character can be rationalized in terms of the resonance forms A–C (Scheme 1).

We have been interested in investigating the different bonding modes have been adopted by ylides when coordinated to Hg (II), Ag (I) and Pd (II).24-27 The C and Ocoordinated complexes of Hg (II) was formed.28-30 In this paper, we report the reactivity of the ligands 4-Bromo benzoyl methylene triphenyl phosphorane (Y1) and 4-Phenyl benzoyl methylene triphenyl phosphorane (Y2), towards mercury (II) halides and silver (I) salts. One of the significance aspects of our work is to ascertain the preferred coordination modes of Y1 and Y2 to the Hg and Ag metals. In this study, we describe the preparation, spectroscopic characterization (IR and NMR) of mercury (II) and silver (I) complexes with the title ylides. By a comparison of the data collected and single crystal x-ray diffraction of 1 and 4, it demonstrates C-coordination of the ylides to the metals.

Scheme 1.

 

RESULTS AND DISCUSSION

Spectroscopy

IR and NMR spectroscopy are suitable indicators for judging the bonding mode of the α-keto ylides. The IR spectra of 1-8 (Table 1) show that ν (CO) absorption at between 1600-1645 cm -1 in the region typical for the Cbonded phosphorus ylides.16 The increasing carbonyl stretching frequency in the IR spectra of these complexes, confirm that the ligand is bound through the carbon of ylide to Hg (II) and Ag (I) center (Table 1, Scheme 2). Similarly, in the 1H and 31P NMR spectra of complexes 1-6 the downfield shift of the signal due to the PCH group are ascribed to C-coordination of the ylide (Table 1). In the 1H NMR spectra of 7 and 8, the singlet at 5.35 and 5.40 ppm, respectively due to the methine proton appear in the downfield. These downfield shifts of the signal due to Ccoordination of the ylide (Table 1, Scheme 3). The resonances of the 31PNMR complexes 1-8 have been observed to occur at a lower field with respect to the free ylide (Table 1, Scheme 2 and 3). The expected downfield shifts of 31P and 1H signals for the PCH group upon complexation were observed in their corresponding spectra. The appearance of single signals for the PCH group in both the 31P and 1HNMR at ambient temperature indicates the presence of only one molecule for all the complexes as expected for C-coordination.31 That the bonding of the ylide to Hg (II) in the chloride complex is much weaker than in the bromide and the iodide complexes is indicative in the 1H NMR spectra in which the methin group resonances appear at δ 4.2, 4.52, 5.22, 5.06, 4.96, 5.5, 5.1, 5.06 and for the free ylides (Y1 and Y2) and complexes 1-6, respectively (Table 1).

Table 1.Selected IR (cm-1), 1H and 31P NMR spectral data [δ (ppm), J (Hz)]

Scheme 2.

Scheme 3.

Although two diasteroisomer (RR/SS and RS) are possible for each complex (because the methine carbons are chiral) NMR spectroscopy dose not distinguish them at room temperature. The methine resonances of complexes (1-8) are intermediate between those in the free ylides and phosphonium salts; this was observed for other C-coordinated carbonyl-stabilized phosphorus ylide complexes and 2JPH values smaller than the free ylides and phosphonium salts: because the hybridization changes in the ylidic carbon (SP2-SP3) in the C-coordination mode.32 Values of 2JPH much larger (ca. 20 Hz) have been observed in complexes where coordination is through the oxygen atom.26

The 13C NMR spectra of the complexes 1-3 is the up field shift of the signals due to the ylidic carbon atoms. Such an up field shift was observed in other complexes is due to the change in hybridization of the ylidic carbon atom on coordination.32 Similar up field shifts of 2-3 ppm with reference to the parent ylide were also observed in the case of complexes of Hg (II) with BPPY complex.33 The 13C shifts of the CO group in the complexes are between 186-189 ppm, which is higher field than the 183.1 ppm noted for the same carbon in the parent ylide, indicating much lower shielding of the carbon atom of the CO group in the complexes. No coupling to Hg was observed at room temperature in the 1H, 13C and 31P NMR spectra. Failure to observe satellites in the above spectra was previously noted in the ylide complexes of Hg (II)33 and Ag (I),34 which had been explained by fast exchange of the ylide with the metal. In other hand it is possible that a fast equilibrium between complexes and free ylides is responsible for the failure observed either the NMR couplings or presence of two diastereoisomers.

X-ray crystallography

Table 2 provides the crystallographic results and refinement information for complexes 1 and 4 (Scheme 2). The molecular structures are shown in Figs. 1 and 2. Selected bond distances and angles for 1 and 4 are given in Tables 3 and 4, respectively. The Hg (II) centre in complex 1 forms four close contacts with sp3 hybridization and has a 4-coordinate environment with one short Hg–Cl (2.393 Ao ) bond, one Hg–C bond and two asymmetric bridging Hg–Cl (bonds at distances of 2.7345 and 2.7090A (Fig. 1). The crystal structure of 1 shows the strongly distorted tetrahedral geometry at the Hg(II) Cl1-Hg1-C19, 147.14.24 The significant shortening of the Hg–C bond length, 2.1979 A compared to analogous distances in [C6H5)3PCHCOC6 H5HgI2]231 and in [(C5H4P (C6H5)3HgI2]233 (2.312(13) and 2.292(8) Ao, respectively) must be attributed to the use of mercury orbital with high s character for bonding to the ylidic carbon. The use of non-equivalent hybrid orbital with high s character to bond to low electronegative atoms was proposed by Bent in the concept of isovalent hybridization to account for the variation in bond lengths and bond angles around a central atom.35 The terminal Hg–Cl bond length, 2.3953Ao is comparable to 2.352 (3)Ao 30 observed in the case of [(EPPY)(HgCl2)]2, which has a tetrahedral coordination environment around.

Table 2.Crystal data and refinement details for complex 1 and 4

Fig. 1.ORTEP view of the X-ray crystal structure of complex 1.

Fig. 2.ORTEP view of the X-ray crystal structure of complex 4.

Table 3.Slected bond lengths (Ao) and angles (o) for the structure [Y1 HgCl2]2.2CHCl3 (1)]

Table 4.Selected bond lengths (Ao) and angles (o) for the structure [Y2 HgCl2]2.CH2Cl2

The Hg(II) centre in complex 4 is coordinated by one carbon and three chloro atoms in a distorted tetrahedral geometry. The two different Hg–Cl distances in 4 (2.3898(10) and 2.5630(8)Ao) are less than those of found in mononuclear complex of [HgCl2(PPh3)2]36 (2.559(2) and 2.545(3) A), indicating relatively strong Hg–Cl bonds in 4. Difference between two distances in these complexes might be arising from steric effects of the large ylidic groups. The angles around mercury in complex 4 vary from 87.39(13) to 139.45(11), indicating a much distorted tetrahedral environment. This distortion must be due to the higher s character of the sp3 hybrid mercury orbital involved in the above bonds and the steric effects of phosphine group needing the C–Hg–Cl angle to be larger mercury with a bridging structure.37 The two bridged Hg–Cl bonds fall within the range 2.620–3.080Ao reported for other structures38 containing chloro bridged mercury. The angles around mercury in complex 1 and 4 vary from 85.13 to 147.14 and 87.20(2) to 133.55(8) for the chloride very distorted tetrahedral environment. This distortion must be due to the higher s character of the sp3 hybrid mercury orbital involved in the above bonds and the formation of a strong chloro bridge between the Hg atoms which requires the internal ClHgCl angle to be considerably smaller. The stabilized resonance structure for the title ylide have been destroyed by the complexes formation. Thus, the C(19)– C(20) bond lengths (1.4964, 1.489(4)Ao) is significantly longer than the corresponding bond found in a similar free ylide (1.407(8)Ao) (Table 5).39 On the other hand, the bond length of P(1)–C(19) in the similar elide is 1.706Ao 24,27,40 which show that the above bond is considerably elongated to 1.7890 and 1.786(3) A in these complexes (Table 5). The elongation of the P–C (methine) bond in 1 and 4 relative to the free ylide supports the localization of the positive charge at the phosphorus (Table 5). The adaptation of dimeric structures in Hg(II) ylide complexes may be explained by both the preference of Hg(II) to four coordination and the stability of the 18 electron configuration around Hg(II). The lengthening of the C–O bond is in the range of a C–O double bond and comparable with that in free ylide (Table 5).

Table 5.Comparison of selected bond lengths in 1 and 4 with Ph3PCHC (O) Ph, [Ph3PCHC (Me)O] TiCl4 (THF)

The C-coordination of the title ylides (Scheme 2 and 3) is in contrast to the O-coordination of the phosphorus ylide Ph3PC (COMe) (COPh) (ABPPY) in a different Hg (II) complex.41 The difference in the coordination mode between ABPPY and the Y1 and Y2 to Hg (II) can be rationalized in terms of the electronic properties, steric requirements, and size and shape of the ligand in the final bonding mode. Belluco et al. have studied steric influences on the coordination modes of ylide molecules to Pt (II) systems.42 These authors concluded that the preferred coordination mode is via the ylidic carbon, but that steric hindrance around the metal centre or the ylidic carbon will necessitate O-coordination. Indeed, this trend is reflected here, Y1 and Y2 are slightly less sterically demanding than ABPPY and are C-coordinated to Hg (II).

 

EXPERIMENTAL

Materials

All the reactions were performed in air. The starting materials were purchased from commercial sources and used without further purification.

Physical measurements

All solvents were reagent grade and used without further purifications. Solution-state 1H and 31P NMR spectra at 300 K were obtained in CDCl3 using a 500 MHz Bruker spectrometer operating at 500.13 MHz for 1H and 161.97 MHz for 31P and referenced to H3PO4 (85%) for 31P{1H}NMR spectra. IR spectra were recorded on a FT-IR JASCO 680 spectrophotometer, and the measurements were made by the KBr disk method. Melting points were measured on a Gallenhamp 9B 3707 F apparatus. Elemental analysis for C, H and N were performed using a PE 2400 series analyzer. The data collection was performed at room temperature using the X-scan technique and using the STOE X-AREA software package.43 The crystal structures were solved by direct methods and refined by full-matrix leastsquares on F2 by SHELXL9744 and using the ORTEP-3 crystallographic software package.45 The independent reflections was measured on an automatic STOE IPDS 2 diffractometer (graphite monochromated Mo–Kα radiation). All non-hydrogen atoms were refined anisotropically using reflections I > 2r (I). Hydrogen atoms were inserted at calculated positions using a riding model with fixed thermal parameters.

Data for ligands

Synthesis of PhC6H4COCH=PPh3: To dichloromethane solution (15 ml) of 2-Bromo 4-Phenyl acetophenone (1.38 g, 5 mmol) was added of PPh3 (1.31g, 5 mmol) and the resulting mixture was stirred for 5h, the suspension was filtered off, the precipitate washed with diethyl ether (25 ml) and air-dried. Further treatment with aqueous NaOH solution (0.5 M) led to elimination of HBr (PH = 7), giving the free ligand. M.p. 230-231 C; Yield (1.87 g, 81.9%); IR (KBr, cm-1): ν 1507; 1H NMR (500 MHz, CDCl3, ppm): δ = 4.52 (d, 1H, CHP, 2JPH = 24 Hz), 7.38 (t 1H, Hp, C6H5) 7.48 (t, 2H, Hm, C6H5), 7.47 (t 2H, Hm, C6H4) 7.53 (m, 6H, Hm, PPh3), 7.6 (m, 2H, Ho, C6H5, 3JHH = 6 Hz), 7.65 (t, 3H, Hp, PPh3, 3JHH = 6 Hz), 7.84 (m, 6H, Ho, PPh3), 8.08 (d, 2H, Ho, C6H4), 31P{-1H}NMR (CDCl3): δ = 17.2 (s, 1P, CHP). 2.4.2.

Data for BrC6H4COC=HPPh3 [25]: M.p: 142 ℃, Anal. Calc for C26H20OPBr: C, 68.03; H, 4.39 Anal Found: C, 68.22; H, 4.28. 13C NMR (CDCl3) δ C: 51.3 (d, 1JPC = 111.2 Hz, CH); 126.2 (d, 1JPC = 93.24 Hz, PPh3 (i)); 127.81 (COPh (m)); 128.88 (PPh3 (p)); 129.34 (d, 3JPC = 12.41 Hz, PPh3 (m)); 131.80 (d, 4JPC = 2.81 Hz, COPh (o)); 133.40 (d, 2JPC = 10.25 Hz, PPh3 (o)); 135.86 (COPh (p)); 140.63 (d, 2JPC = 14.69 Hz, COPh (i)); 183.1 (d, 2JPC = 3.3 Hz, CO).

Synthesis of the complexes of complexes HgX2Y2 {Ye = Y1; X = Cl (1), Br(2), I(3), Ye = Y2; X = Cl(4), Br(5), I(6)}. General procedure for complexes

The following general procedure was used for preparing the complexes 1-6. To a solution (5 ml) of HgX2 (0.5 mmol) in ethanol (5 ml), a solution of Y1 (0.223 g, 0.5 mmol) in ethanol (10 ml) was add drop wise at room temperature and stirred for 4h. The resulting solid was treated with dichloromethane (25 ml) and filtered through celit. Addition of excess diethylether (15 ml) to the concentrated filtrate caused the precipitation of products as white or pale yellow solids. These solid products have been separated by filtration and washed with ethanol. The complexes were purified by repeating the precipitation two times and the solid dried under vacuum.

Data for [Y1. HgCl2]2 (1): Yield: 92.0%, M.p: 214 ℃, IR (cm-1), v(C=O):1635 Anal. Calc for C52H40 Br2Cl4Hg2 P2O2: C, 42.75; H, 2.76 Anal Found: C, 42.45; H, 2.83. 1H NMR (500 MHz, CDCl3, and ppm); 5.51(d, 1H, CH, 2JPH = 10.25 Hz), 7.1-8.2 (m, 19H, Ph) ppm and 31P NMR (CDCl3): 21.79 ppm. 13C NMR (CDCl3) δ: 47.2 (d, 1JPC = 73.2 Hz, CH); 123.33 (d, 1JPC = 86.7 Hz, PPh3 (i)); 127.81 (COPh (m)); 129.8 (d, 3JPC = 12.35 Hz, PPh3 (m)); 130.5 (COPh (p)); 129.74 (PPh3 (p)); 132.8 (d, 2JPC = 9.46 Hz, PPh3 (o)); 136.8 (COPh (o)); 137.3(COPh (i)); 189.82 (s, CO).

Data for [Y1. HgBr2]2 (2): Yield: 81%, M.p: 214 ℃, IR (cm-1), v(C=O):1621 Anal. Calc for C52H40 Br6Hg2P2O2: C, 38.10; H, 2.46 Anal Found: C, 38.08; H, 2.33. 1H NMR (500 MHz, CDCl3, and ppm); 4.62 (d, 1H, CH, 2JPH = 5.5 Hz), 7.1-8 (m, 19H, Ph) ppm and 31P NMR (CDCl3): 20.34 ppm. 13C NMR (CDCl3) δ: 48.45 (d, 1JPC = 81.3 Hz, CH); 126.13 (d, 1JPC = 89.97 Hz, PPh3 (i)); 129.12 (COPh (m)); 121.13(d, 3JPC = 11.52 Hz, PPh3 (m)); 130.54 (PPh3 (p)); 133.25 (d, 2JPC = 9.61 Hz, PPh3 (o)); 134.43 (COPh (p)); 137.3(COPh (o)); 137.92 (COPh (i)); 188.31 (s, CO).

Data for [Y1. HgI2]2: Yield: 76%, M.p: 204 ℃ (dec), IR (cm-1), v(C=O): 1618 Anal. Calc for C52H40Br4Hg2I2 P2O2: C, 34.19; H, 2.21 Anal Found: C, 34.05; H, 2.13. 1H NMR (500 MHz, CDCl3, ppm): 5.48 (s br, 1H, CH), 7. -8.1 (m, 19H, Ph) ppm and 31P NMR (CDCl3): 21.86 ppm. 13CNMR (CDCl3) δ: 49.52 (d, 1JPC = 83.77 Hz, CH); 123.62 (d, 1JPC = 90.23 Hz, PPh3 (i)); 126.15 (COPh (m)); 128.89 (d, 3JPC = 12.15 Hz, PPh3 (m)); 131.62 (PPh3 (p)); 133.25 (d, 2JPC = 10.12 Hz, PPh3 (o)); 134.21 (COPh (p)); 136.94 (COPh (o)); 138.65 (d, 3JPC = 10.64 Hz, COPh (i)); 186.83 (s, CO).

Data for [Y2. HgCl2]2 (4): M.p. 218-220 ℃. Yield: 0.1098 gr (75.4%), IR (cm-1), ν (C=O): 1644.98, Anal. Calc for C64H50Cl4Hg2P2O2: C, 52.78; H, 3.46; Found. C; 51.7 H; 3.19 1H NMR (500 MHz, CDCl3, ppm); δ = 5.5 (s, 1H, CHP ), δ = 7.36 (t, 1H, Hp C6H5, 3jHH = 7.3HZ), δ = 7.425 (t, 2H, Hm C6H5, 3jHH = 7.74Hz), δ = 7.56 (m, 6H, Hm, PPh3), δ = 7.625 (m, 5H, Hp PPh3+ Ho C6H5), δ = 7.678 (d, 2H, Hm C6H4, 3jHH = 13.86HZ), δ = 7.775 (d of d, 6H, Ho, PPh3), δ = 8.21 (d, 2H, Ho C6H4, 3jHH = 8.235 HZ). 31P{1H} NMR (CDCl3): δ = 27.45 (s, 1P CHP).

Data for [Y2. HgBr2]2 (5): M.p. 236 ℃. Yield: .126gr (77.1%), IR (cm-1), ν (C=O):1627.63, Anal. Calc for C64H50Br4Hg2P2O2: C, 47.05; H, 3.08. Found. C; 46.88, H; 3.12.1H NMR (500 MHz, CDCl3, ppm): δ = 5.1 (s, 1H, CHP), 7.38 (m, 2H, Hm, C6H5), δ = 7.33(t, 2H, Hm, C6H4CO) δ = 7.46 (sbr, 6H, Hm) δ = 7.51(2H, Ho C6H5), δ = 7.56 (sbr, 5H, Hp PPh3+Ho C6H4) δ = 7.65 (m, 6H, Ho PPh3) δ = 8.025 (d, 2H, Ho, C6H4CO, 3jHH = 7.6Hz), 31P{-1H}NMR (CDCl3): δ = 25.6 (s, 1P, PPh3)

Data for [Y2. HgI2]2 (6): M.p. 130-132 ℃. Yield: 1.27 gr (69.5%), IR (cm-1), ν (C=O):1622.8, Anal. Calc for C64H50Hg2I4P2O2: C, 42.19; H, 2.77. Found. C;41.7 H; 2.83 , 1H NMR (500 MHz, CDCl3, ppm); δ = 5.06 (s, 1H CHP), δ = 7.36 (t, 1H Hp C6H5,3jHH = 6.9HZ), δ = 7.45 (t, 2H, Hm C6H5, 3jHH = 7.14Hz), δ = 7.58 (s br, 6H, Hm, PPh3), δ = 7.70 (m, 13H, 3Hp PPh3+ 6Ho C6H5+ 2Ho C6H5+ 2Hm C6H4), δ = 8.01 (d, 2H, Ho C6H4, 3jHH = 7.46HZ). 31P {1H} NMR (CDCl3): δ = 20.54 (s, 1P, PPh3).

Syntheses of [Ag (Y2) 2] X (X = BF4 (7), OTf (8)) General procedure for complexes

The ylide PhBPPY (0.457 g, 1 mmol) was added to a solution of AgX (0.5 mmol) in acetone (10 mL). The solution was stirred for 1 h during which it was protected from light and then filtered. The volume of solvent was reduced under vacuum to 2 mL. Diethyl ether (25 mL) was added to precipitate white solid.

Data for [Ag (Y2) 2] BF4 (7): M.p.150 ℃ (dec). Yield: 0.068 (61.4%), IR (cm-1), ν (C=O): 1600.63, Anal. Calc for C64H50 AgBF4P2O2: C, 69.39; H, 4.55, Found: H; 69.12, H; 4.51.1H NMR (500 MHz, CDCl3, ppm): δ = 5.35 (s, 1H, CHP), 7.42(s br, 8H, Hm C6H5+Hm PPh3), δ = 7.65 (m br, 13H, Hp PPh3+Ho C6H5+Hm C6H4), δ = 8.11 (d, 2H, Ho C6H4, 3jHH = 7.65Hz), 31P{1H}NMR (CDCl3): δ = 24.8 (s, 1P, PPh3).

Data for [Ag (Y2) 2] TfO (8): M.p. 210 ℃, Yield: 0.0744gr (63.6%), IR (cm-1), ν (C=O): 1600.68, Anal. Calc C65H50 AgF3P2O5S,: C, 66.75; H, 4.31. Found: H; 65.15, H; 4.21. 1H NMR (500 MHz, CDCl3, ppm): δ = 5.4 (s, 1H, CHP), 7.26 (m br, 6H, Hm PPh3), δ = 7.35(d, 1H, Hp C6H5, 3jHH = 7.86HZ), δ = 7.58 (d, 2H Hm, C6H4, 3jHH = 7.6 Hz), δ = 8.14 (d, 2H, Ho C6H4, 3jHH = 7.89Hz). 31P{1H}NMR (CDCl3): δ = 24.48 (s, 1P, PPh3).

 

CONCLUSION

The present study describes the synthesis and characterization of a series of dimeric mercury (II) and bisylide silver (I) complexes derived from mercuric halides or silevr (I) with phosphorus ylides. On the basis of the physico-chemical and spectroscopic data, we propose that the ligands herein exhibit monodentate C-coordination to the metal centre, which is further confirmed by the X-ray crystal structure of the complexes.