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Synthesis and structures of new octahedral water-soluble heterometal rhenium–molybdenum clusters
Polyhedron 23 (2004) 599–603 www.elsevier.com/locate/poly
Synthesis and structures of new octahedral water-soluble heterometal rhenium–molybdenum clusters Nikolai G. Naumov a,b, Konstantin A. Brylev b, Yuri V. Mironov b, Alexander V. Virovets b, Dieter Fenske c,1, Vladimir E. Fedorov a,b,* a Novosibirsk State University, 2 Pirogova st., 630090 Novosibirsk, Russia Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3 prosp. Akad. Lavrentieva, 630090 Novosibirsk, Russia Institut f€ur Anorganische Chemie, Universit€at Karlsruhe, Engesserstrasse 30.45, D-76128 Karlsruhe, Germany b
c
Received 9 July 2003; accepted 22 October 2003
Abstract The interaction of polymeric Re3 MoS4 Te4 with molten KCN at 850 °C results in rearrangement of the tetrahedral {Re3 MoS4 } cluster core to an octahedral one, {Re6x Mox S8 }, and formation of two new molecular octahedral heterometal rhenium–molybdenum thiocyanide cluster complexes, [Re5 MoS8 (CN)6 ]5 and [Re4 Mo2 S8 (CN)6 ]5 , co-existing in the crystals Cs5 [Re4:5 Mo1:5 (l3 S)8 (CN)6 ] 2H2 O. The EDAX analyses and magnetic measurements data confirm the presence of a mixture of cluster anions with x ¼ 1 and 2. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: EDAX analyses; Anisotropic approximation; Cluster anions; Heterometal cluster complexes
1. Introduction Among a variety of octahedral chalcogenide cluster compounds of transition metals (1–4 and references herein) there are few examples containing mixed-metal cluster cores Mo6 x Mx Q8 (M ¼ Re, Q ¼ S, Se, Te, x ¼ 4; M ¼ Ru, Q ¼ Se, Te, 0 6 x 6 2; M ¼ Rh, Q ¼ Te, x ¼ 0:5, 1.33) [5], Nb6 x Rux Te8 (2:50 6 x 6 3:17) [6], Cs3 Re5 OsS11 [7]. These compounds have been prepared by routine solid state synthesis and are insoluble in water and common organic media. The only soluble heterometal cluster complexes Cs3 Re6 x Osx Se8 Cl6 (x ¼ 1, 2) and K2 [Re3 Os3 Se8 Cl6 ][Re4 Os2 Se7 Cl7 ] were reported very recently [8]. In the present work we report the synthesis and crystal structure of the first soluble mixed metal rhenium–molybdenum cluster complexes with terminal cy*
Corresponding author. Tel.: +7-3832-344253; fax: +7-3832-344489. E-mail addresses: [email protected] (D. Fenske), [email protected] (V.E. Fedorov). 1 Fax: +49(0721)-661921. 0277-5387/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.poly.2003.10.017
ano-ligands [Re6 x Mox (l3 -S)8 (CN)6 ]5 . The compound was prepared with moderate yield by the reaction of polymeric solid Re3 MoS4 Te4 containing a tetrahedral cluster core with molten KCN at 850 °C.
2. Experimental 2.1. Materials and methods X-ray powder diffraction patterns were collected on a Philips APD 1700 diffractometer (Cu Ka radiation, graphite monochromator) in the 2h range 5°–80°. UV– Vis spectra were recorded on an Ultrospec 3300 pro spectrophotometer in the range of 200–1100 nm. IR spectra were recorded on a Bruker IFS-85 spectrometer in KBr pellets. KCN, CsCl were used as purchased. Re4 x Mox S4 Te4 (x ¼ 0:67, 1, 1.33 and 2) were prepared as described in [9]. X-ray diffractometry revealed the identity of these phases. The Re2 Mo2 S4 Te4 sample contained traces of MoS2 , other samples were single phase.
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A mixture of Re3 MoS4 Te4 (1 g, 0.773 mmol) and KCN (0.5 g, 7.678 mmol) was placed in a quartz tube. The tube was evacuated, sealed and kept at 850 °C for 48 h. The products of the reaction were put in 50 ml of water, boiled until potassium polytelluride decomposed and was filtered off. CsCl (0.5 g, 2.970 mmol) was added to the solution. The dark-brown solution was reduced to 2 ml and slowly cooled. The well shaped dark-brown crystals were separated by filtration and dried in air. The yield of the crystals of 1 was 0.612 g (56.67%). Chemical analysis, %: found (calcd.) Cs 31.50 (31.72), Re 39.90 (40.00), Mo 6.92 (6.87), S 12.10 (12.25). EDAX for different crystals: energy dispersive spectrometry (EDS) analyses performed on two selected single-crystals led to the following average atomic percentage, Cs/Re/Mo/S: 5.05/4.20/1.80/7.90 for crystal 1 and Cs/Re/Mo/S: 4.95/ 4.40/1.60/8.05 for crystal 2. IR, cm1 : 1605 (dHOH ), 2106 (mCN ), 3574 (mOH ), UV–Vis [k/nm (e/M1 cm1 per cluster)] 455 (747), 472 (720), 490 (651) and 526 (276). leff ¼ 1:08 lB (300 K). 2.1.1. Crystallography X-ray structural analysis was carried out for two crystals on a STOE Stadi4 four-circle diffractometer graphite monochromator, stan(Mo Ka , k ¼ 0:7107 A, dard techniques). Both crystals of Cs5 [Re6 x Mox (l3 S)8 (CN)6 ] 2H2 O in the form of dark brown hexagonal prisms were manually selected from the bulk sample. 2.1.2. Crystal data for the first crystal (data were collected at 211 K, size: 0.15 0.14 0.10 mm) C6 H4 Cs5 Mo1:79 N6 O2 Re4:21 S8 , M ¼ 2068:82, trigonal crystal system, space group P 3c1, a ¼ 9:792ð3Þ A, V ¼ 1589:7ð18Þ A 3 , Z ¼ 2, Dc ¼ 4:322 g c ¼ 19:14ð2Þ A, cm3 . A total of 2116 reflections were collected up to 2hmax ¼ 50°, of which 946 were unique (Rint ¼ 0:0598). Absorption corrections (l ¼ 22:835 mm1 ) were applied by integration from the crystal shape, transmission factors ranging from 0.0614 to 0.0190. The crystal is merohedry twin with law of (1 0 0/0 1 0/0 0 )1). The structure was solved by direct methods and refined by full-matrix least-squares on F 2 with an anisotropic approximation using S H E L X -97 [10]. Hydrogen atoms were not located. Metal atom positions correspond to the mixture of Mo and Re atoms. The relative occupancy factors were refined together with the rest parameters without constrains. Final R values: R1 ¼ 0:0378, wR2 ¼ 0:0903 for 808 Fo P 4rðF Þ, R1 ¼ 0:0527, wR2 ¼ 0:0967, GOF ¼ 1:100 for all unique data, relative weights of twin components are 0.313(3) and 0.687(3). 2.1.3. Crystal data for the second crystal (data were collected at room temperature, size: 0.19 0.18 0.12 mm) C6 H4 Cs5 Mo1:64 N6 O2 Re4:36 S8 , M ¼ 2082:81, trigonal crystal system, space group P 3c1, a ¼ 9:838ð3Þ A,
V ¼ 1608:9ð9Þ A 3 , Z ¼ 2, Dc ¼ 4:299 g c ¼ 19:195ð6Þ A, 3 cm . A total of 4051 reflections were collected up to 2hmax ¼ 50°, of which 1240 were unique (Rint ¼ 0:0954). Absorption corrections (l ¼ 23:084 mm1 ) were applied by integration from the crystal shape, transmission factors ranging from 0.9952 to 0.5312. The crystal is merohedry twin with law of (1 0 0/0 1 0/0 0 )1). The structure was solved by direct methods and refined by full-matrix least-squares on F 2 with an anisotropic approximation using S H E L X -97 [10]. As in the first crystal, metal atom positions correspond to the mixture of Mo and Re atoms. The relative occupancy factors also were refined together with the rest parameters without constrains. Hydrogen atoms were not located. Final R values: R1 ¼ 0:0406, wR2 ¼ 0:0765 for 808 Fo P 4rðF Þ, R1 ¼ 0:0678, wR2 ¼ 0:0905, GOF ¼ 1:125 for all unique data. Relative weights of twin components are 0.408(3) and 0.592(3). Crystal data and selected bond lengths for the two crystals are given in the Tables 1 and 2, respectively. Table 1 Crystal data and structure refinements for Cs5 [Re4:21 Mo1:79 S8 (CN)6 ] 2H2 O (1) and Cs5 [Re4:36 Mo1:64 S8 (CN)6 ] 2H2 O (2) Compound
1
2
Chemical Formula Formula weight Space group a (A) c (A) 3 ) V (A
C6 H4 Cs5 Mo1:79 N6 O2 - C6 H4 Cs5 Mo1:63 N6 O2 Re4:21 S8 Re4:36 S8 2068.82 2082.81 P3c1 P 3c1 9.792(3) 9.838(3) 19.14(2) 19.195(6) 1589.7(18) 1608.9(9) Z 2 2 k (A) 0.71073 0.71073 T (K) 211 293 qcalc (g/cm3 ) 4.322 4.299 228.35 230.84 l (cm1 ) RðF Þa 0.0378 0.0406 Rw ðF 2 Þ 0:0967b 0:0905c P P a RðF Þ ¼ jjF j for Fo2 > 2rðFo2 ). Po j jFc jj= jFo P b Rw ðFo2 Þ ¼ f ½wðFo2 Fc2 Þ2 = wFo4 g w1 ¼ r2 ðFo2 Þ þ ð0:053Fo2 Þ2 for Fo2 P 0 and w1 ¼ r2 ðFo2 Þ for Fo2 < 0. P P c Rw ðFo2 Þ ¼ f ½wðFo2 Fc2 Þ2 = wFo4 g w1 ¼ r2 ðFo2 Þ þ ð0:028Fo2 Þ2 2 1 2 2 for Fo P 0 and w ¼ r ðFo Þ for Fo2 < 0.
Table 2 for Cs5 [Re4:21 Mo1:79 S8 (CN)6 ] 2H2 O (1) and Selected bond lengths (A) Cs5 [Re4:36 Mo1:64 S8 (CN)6 ] 2H2 O (2)a Compound
1
2
Re,Mo(1)–Re,Mo(1)#1 Re,Mo(1)–Re,Mo(1)#2 Re,Mo(1)–S(1) Re,Mo(1)–S(2) Re,Mo(1)–S(2)#1 Re,Mo(1)–S(2)#2 Re,Mo(1)–C(1) C(1)–N(1)
2.619(2) 2.6201(14) 2.444(6) 2.449(4) 2.458(4) 2.459(4) 2.151(17) 1.14(2)
2.6244(13) 2.6268(13) 2.443(5) 2.458(4) 2.463(4) 2.4588(4) 2.139(16) 1.14(2)
a
#1: x; y þ 1; z; #2: x þ y 1; x þ 1; z. Symmetry transformation used to generate equivalent atoms.
N.G. Naumov et al. / Polyhedron 23 (2004) 599–603
Ref. Mean (M–Q)
2.454 2.411 2.457(1) 2.444 2.452(7) 2.455(7) 2.462(3) 2.447(4) 2.452(2) 2.452(2) 2.459 2.415 0.191 0.031 0 0.011 0.013 0.020 0.012 0.028 0.034 0 0.015 0.024
D(M–Q) M–Q
2.399–2.590 2.398–2.429 2.457(1) 2.438–2.449 2.444(6)–2.459(4) 2.443(5)–2.463(4) 2.455(3)–2.467(3) 2.435(4)–2.463(3) 2.431(2)–2.465(2) 2.452(2) 2.452(2)–2.467(1) 2.398(4)–2.422(3) 2.603 2.602 2.666(1) 2.663 2.620 2.626(2) 2.644(2) 2.649(2) 2.649(1) 2.6772(7) 2.685(3) 2.617
Mean (M–M) D(M–M)
0.01 0.01 0 0.002 0.001 0.003 0.006 0.037 0.021 0 0.006 0.005
The concurrent formation of Re4 and Re6 clusters realized in high temperature reactions is known. The study of Re–Te–Cl and Re–Se–Cl systems showed that Re4 clusters are stable below 400 °C, while above this temperature Re6 ones are stable [11]. Up to now Re4 S4 Te4 [12] found in the ternary Re–S–Te system is the only tetrahedral cluster compound stable at 900 °C. Our preliminary study of the interaction of the Re4 S4 Te4 with molten KCN at 850 °C showed that the reaction resulted in rearrangement from a Re4 to Re6 cluster core and formation of a compound isostructural to the known cubic phase Cs3 K[Re6 (l3 -S)6 (l3 Te0:66 S0:34 )2 (CN)6 ] [13] with cell parameters a ¼ 17:80ð1Þ V ¼ 5640 A 3 . Therefore we could expect that hetA, erometallic Re4 x Mox S4 Te4 [9] clusters can be used as starting materials for preparation of new compounds with an octahedral {Re6 x Mox } cluster core. The interaction of the tetrahedral heterometallic cluster compound Re3 MoS4 Te4 under the conditions reported in Section 2 leads to the formation of a compound with an average composition Cs5 [Re4:5 Mo1:5 (l3 S)8 (CN)6 ] 2H2 O. EDAX for a set of single crystals showed that the Re/Mo ratio for them vary in the range Re4:2 Mo1:8 –Re4:5 Mo1:5 , while the Cs/(Re,Mo) ratio is nearly constant. No remarkable amount of tellurium presents in the tested crystals. All crystals in the synthesis have the same shape, hexagonal prisms. It should mean that all of them have the same structure, which was confirmed by measuring the powder diffraction pattern. The X-ray powder diffraction and EDAX data show that we have a typical solid solution with variable
[13] [18] [16] [19] this work this work [20] [20] [20] [17] [17] [7]
3. Discussion
Fig. 1. Anion in 2 (a.d.p. ellipsoids at 50% probability level). Some (Re,Mo)–(Re,Mo), 2.624(1)–2.627(1), av. geometrical parameters (A): 2.626[2]; (Re,Mo)-l3 -S, 2.443(5)–2.463(4), av. 2.455[7]; (Re,Mo)–C, 2.139(16); C–N, 1.14(2).
2.598–2.608 2.597–2.607 2.666(1) 2.662–2.664 2.619(2)–2.620(1) 2.624(1)–2.627(1) 2.641(2)–2.647(2) 2.635(2)–2.672(2) 2.637(1)–2.658(1) 2.6772(7) 2.6818(4)–2.6875(4) 2.614(2)–2.619(2)
S2
M–M
(Re,Mo)1
KCs3 Re6 S8 (CN)6 NaCs3 Re6 S8 (CN)6 K7 [Mo6 S8 (CN)6 ] 8H2 O [Mo6 S8 (PEt3 )6 ] Cs5 [Re4:21 Mo1:79 S8 (CN)6 ] 2H2 O Cs5 [Re4:36 Mo1:64 S8 (CN)6 ] 2H2 O Mo6 S8 (py)6 2py Mo6 S8 (pyrr)6 pyrr Mo6 S8 (pip)6 7pip K6 W6 S8 (CN)6 10H2 O Na6 W6 S8 (CN)6 18DMSO Cs5 Re5 OsS11
S1
Compounds
C1
Table 3 in the octahedral cluster cores {M6 Q8 } Interatomic distances (A)
N1
601
602
N.G. Naumov et al. / Polyhedron 23 (2004) 599–603
composition, namely, different crystals belonging to the same structural type have variable Re/Mo ratio. To investigate this phenomenon we have selected two crystals for X-ray structural analysis. Both of them appeared to be merohedry twins which is typical for trigonal crystals with hexagonal shape. As expected the structures of both crystals were the same but relative Re/Mo occupancies are different. The cluster anion in the structure of the reported compounds (Fig. 1) has a structure which is similar to well-known [M6 Q8 (CN)6 ]n octahedral chalcocyanide cluster complexes (M ¼ Re, Q ¼ S, Se, Te, n ¼ 3, 4 [13,14]; M ¼ Mo, Q ¼ S, Se, n ¼ 6, 7 [15,16]; M ¼ W, Q ¼ S, n ¼ 6 [17]). As usual, the metal octahedron is surrounded by eight l3 -S ligands forming a S8 cube. Additionally each metal atom is coordinated by the linear CN ligand through the C atom. Average bond lengths are given in Table 3 together with the data for other related compounds. We can see that Re–Re bond are significantly distances in [Re6 S8 (CN)6 ]4 (2.603 A) shorter than Mo–Mo bond distances in [Mo6 S8 (CN)6 ]7 X-ray structural analysis shows that the me(2.666 A). tal–metal bond distances in our heterometallic phase, [Re6 x Mox (l3 -S)8 (CN)6 ]5 , depend on the value of x (2.619(2)–2.620(1) and 2.624(1)–2.627(1) for x ¼ 1:79 and x ¼ 1:63, respectively, Table 3), lying in the range between Re–Re and Mo–Mo. The M–S distances for all [M6 S8 (CN)6 ]n (M ¼ Mo, W, Re; n ¼ 4, 5, 6, 7) anions are almost the same and therefore are not sensitive to N
C
the nature of the metal atoms. The crystal packing is shown in Fig. 2. All the experimental data show that the prepared phase is the solid solution of cesium salts of different [Re6 x Mox S8 (CN)6 ]5 anions. Because the average value of x is close to 1.5 we can expect that we have mixture of [Re5 MoS8 (CN)6 ]5 and [Re4 Mo2 S8 (CN)6 ]5 clusters. The structural and EDAX data show that the Cs/(Re,Mo) ratio is constant. It means that both anions have the same charge, 5. From this it is possible to conclude that the valence electron concentration (VEC) for the [Re5 MoS8 (CN)6 ]5 anion is equal to 24 electrons and this anion is diamagnetic, while [Re4 Mo2 S8 (CN)6 ]5 has a VEC ¼ 23 and is paramagnetic. The measured value of effective magnetic moment, 1.08 MB, is in good agreement with the suggestion that only half of the cluster units contain an unpaired electron. We also have investigated the reaction of other phases in the Re4 x Mox S4 Te4 series [9] with molten KCN and found that under similar experimental conditions similar phases with different Re/Mo ratio were formed. The crystallization with CsCl resulted in phases isostructural to crystals 1 and 2. EDAX analysis made on several crystals gave compositions summarized in Table 4. We can suppose that these phases contain {Re5 Mo}, {Re4 Mo2 } and {Re3 Mo3 } octahedral clusters. In conclusion, interaction of tetrahedral Re4 x Mox S4 Te4 cluster compounds with molten KCN leads to the formation of octahedral heterometallic [Re6 x Mox S8 (CN)6 ]5 cluster anions, x ¼ 1, 2 co-existing in the crystals Cs5 [Re6 x Mox (l3 -S)8 (CN)6 ] 2H2 O. The solubility of these salts opens the way for further study of the chemical properties of Re–Mo heterometallic cluster complexes.
Cs
4. Supplementary data
Fig. 2. Crystal packing in 2. Sulfur atoms are omitted for clarity.
Supplementary data are available from the CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax: +44-1223336033; E-mail: [email protected] or www: http:// www.ccdc.cam.ac.uk) on request, quoting the deposition Nos. 391226 and 391227.
Table 4 Expected and found Re/Mo ratios in Cs5 [Re6 x Mox S8 (CN)6 ] 2H2 O series Starting polymeric solid
Expected Re/Mo ratio in octahedral cluster
Experimental Re/Mo ratio averaged by several crystals
Yield of salt, %
Re3:33 Mo0:67 S4 Te4 Re3 MoS4 Te4 Re2:7 Mo1:3 S4 Te4 Re2 Mo2 S4 Te4
Re5 Mo Re4:5 Mo1:5 Re4 Mo2 Re3 Mo3
Re4:9 Mo1:1 Re4:4 Mo1:6 Re4:1 Mo1:9 Re3:8 Mo2:2
40 56.7 45 15
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Acknowledgements This work was supported by the Program ‘‘Universities of Russia’’ of the Education Ministry of Russian Federation, Grant UR.05.01.038.
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[9] G.F. Khudorozhko, E.A. Kravtsova, L.N. Mazalov, V.E. Fedorov, L.G. Bulusheva, I.P. Asanov, G.K. Parygina, Y.V. Mironov, J. Struct. Chem. (Engl. Transl.) 37 (1996) 767. [10] G.M. Sheldrick, S H E L X -97 Release 97-2, G€ ottingen University, G€ ottingen, Germany, 1997. [11] Y.V. Mironov, V.E. Fedorov, J. Struct. Chem. (Engl. Transl.) 40 (1999) 959. [12] V.E. Fedorov, Y.V. Mironov, V.P. Fedin, H. Imoto, T. Saito, Acta Cryst. C 52 (1996) 1065. [13] (a) Y.V. Mironov, A.V. Virovets, V.E. Fedorov, N.V. Podberezskaya, O.V. Shishkin, Y.T. Struchkov, Polyhedron 14 (1995) 3171; (b) A. Slougui, Y.V. Mironov, A. Perrin, V.E. Fedorov, Croat. Chem. Acta 68 (1995) 885. [14] (a) Y.V. Mironov, J.A. Cody, T.A. Albrecht-Schmitt, J.A. Ibers, J. Am. Chem. Soc. 119 (1997) 493; (b) N.G. Naumov, A.V. Virovets, N.V. Podberezskaya, V.E. Fedorov, J. Struct. Chem. (Engl. Transl.) 38 (1997) 857; (c) H. Imoto, N.G. Naumov, A.V. Virovets, T. Saito, V.E. Fedorov, J. Struct. Chem. (Engl. Transl.) 39 (1998) 720; (d) N.G. Naumov, E.V. Ostanina, A.V. Virovets, M. Schmidtmann, A. Muller, V.E. Fedorov, Russ. Chem. Bull. 51 (2002) 866. [15] Y.V. Mironov, A.V. Virovets, N.G. Naumov, V.N. Ikorskii, V.E. Fedorov, Chem. Eur. J. 8 (2000) 1361. [16] K.A. Brylev, A.V. Virovets, N.G. Naumov, Y.V. Mironov, D. Fenske, V.E. Fedorov, Russ. Chem. Bull. 50 (2001) 1140. [17] S. Jin, F.J. DiSalvo, Chem. Commun. (2001) 1586. [18] L.G. Beauvais, M.P. Shores, J.R. Long, Chem. Mater. 10 (1998) 3783. [19] T. Saito, N. Yamamoto, T. Yamagata, H. Imoto, J. Am. Chem. Soc. 110 (1988) 1646. [20] S.J. Hilsenbeck, V.G. Young Jr., R.E. McCarley, Inorg. Chem. 33 (1994) 1822.
Synthesis and structures of new octahedral water-soluble heterometal rhenium–molybdenum clusters Nikolai G. Naumov a,b, Konstantin A. Brylev b, Yuri V. Mironov b, Alexander V. Virovets b, Dieter Fenske c,1, Vladimir E. Fedorov a,b,* a Novosibirsk State University, 2 Pirogova st., 630090 Novosibirsk, Russia Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3 prosp. Akad. Lavrentieva, 630090 Novosibirsk, Russia Institut f€ur Anorganische Chemie, Universit€at Karlsruhe, Engesserstrasse 30.45, D-76128 Karlsruhe, Germany b
c
Received 9 July 2003; accepted 22 October 2003
Abstract The interaction of polymeric Re3 MoS4 Te4 with molten KCN at 850 °C results in rearrangement of the tetrahedral {Re3 MoS4 } cluster core to an octahedral one, {Re6x Mox S8 }, and formation of two new molecular octahedral heterometal rhenium–molybdenum thiocyanide cluster complexes, [Re5 MoS8 (CN)6 ]5 and [Re4 Mo2 S8 (CN)6 ]5 , co-existing in the crystals Cs5 [Re4:5 Mo1:5 (l3 S)8 (CN)6 ] 2H2 O. The EDAX analyses and magnetic measurements data confirm the presence of a mixture of cluster anions with x ¼ 1 and 2. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: EDAX analyses; Anisotropic approximation; Cluster anions; Heterometal cluster complexes
1. Introduction Among a variety of octahedral chalcogenide cluster compounds of transition metals (1–4 and references herein) there are few examples containing mixed-metal cluster cores Mo6 x Mx Q8 (M ¼ Re, Q ¼ S, Se, Te, x ¼ 4; M ¼ Ru, Q ¼ Se, Te, 0 6 x 6 2; M ¼ Rh, Q ¼ Te, x ¼ 0:5, 1.33) [5], Nb6 x Rux Te8 (2:50 6 x 6 3:17) [6], Cs3 Re5 OsS11 [7]. These compounds have been prepared by routine solid state synthesis and are insoluble in water and common organic media. The only soluble heterometal cluster complexes Cs3 Re6 x Osx Se8 Cl6 (x ¼ 1, 2) and K2 [Re3 Os3 Se8 Cl6 ][Re4 Os2 Se7 Cl7 ] were reported very recently [8]. In the present work we report the synthesis and crystal structure of the first soluble mixed metal rhenium–molybdenum cluster complexes with terminal cy*
Corresponding author. Tel.: +7-3832-344253; fax: +7-3832-344489. E-mail addresses: [email protected] (D. Fenske), [email protected] (V.E. Fedorov). 1 Fax: +49(0721)-661921. 0277-5387/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.poly.2003.10.017
ano-ligands [Re6 x Mox (l3 -S)8 (CN)6 ]5 . The compound was prepared with moderate yield by the reaction of polymeric solid Re3 MoS4 Te4 containing a tetrahedral cluster core with molten KCN at 850 °C.
2. Experimental 2.1. Materials and methods X-ray powder diffraction patterns were collected on a Philips APD 1700 diffractometer (Cu Ka radiation, graphite monochromator) in the 2h range 5°–80°. UV– Vis spectra were recorded on an Ultrospec 3300 pro spectrophotometer in the range of 200–1100 nm. IR spectra were recorded on a Bruker IFS-85 spectrometer in KBr pellets. KCN, CsCl were used as purchased. Re4 x Mox S4 Te4 (x ¼ 0:67, 1, 1.33 and 2) were prepared as described in [9]. X-ray diffractometry revealed the identity of these phases. The Re2 Mo2 S4 Te4 sample contained traces of MoS2 , other samples were single phase.
600
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A mixture of Re3 MoS4 Te4 (1 g, 0.773 mmol) and KCN (0.5 g, 7.678 mmol) was placed in a quartz tube. The tube was evacuated, sealed and kept at 850 °C for 48 h. The products of the reaction were put in 50 ml of water, boiled until potassium polytelluride decomposed and was filtered off. CsCl (0.5 g, 2.970 mmol) was added to the solution. The dark-brown solution was reduced to 2 ml and slowly cooled. The well shaped dark-brown crystals were separated by filtration and dried in air. The yield of the crystals of 1 was 0.612 g (56.67%). Chemical analysis, %: found (calcd.) Cs 31.50 (31.72), Re 39.90 (40.00), Mo 6.92 (6.87), S 12.10 (12.25). EDAX for different crystals: energy dispersive spectrometry (EDS) analyses performed on two selected single-crystals led to the following average atomic percentage, Cs/Re/Mo/S: 5.05/4.20/1.80/7.90 for crystal 1 and Cs/Re/Mo/S: 4.95/ 4.40/1.60/8.05 for crystal 2. IR, cm1 : 1605 (dHOH ), 2106 (mCN ), 3574 (mOH ), UV–Vis [k/nm (e/M1 cm1 per cluster)] 455 (747), 472 (720), 490 (651) and 526 (276). leff ¼ 1:08 lB (300 K). 2.1.1. Crystallography X-ray structural analysis was carried out for two crystals on a STOE Stadi4 four-circle diffractometer graphite monochromator, stan(Mo Ka , k ¼ 0:7107 A, dard techniques). Both crystals of Cs5 [Re6 x Mox (l3 S)8 (CN)6 ] 2H2 O in the form of dark brown hexagonal prisms were manually selected from the bulk sample. 2.1.2. Crystal data for the first crystal (data were collected at 211 K, size: 0.15 0.14 0.10 mm) C6 H4 Cs5 Mo1:79 N6 O2 Re4:21 S8 , M ¼ 2068:82, trigonal crystal system, space group P 3c1, a ¼ 9:792ð3Þ A, V ¼ 1589:7ð18Þ A 3 , Z ¼ 2, Dc ¼ 4:322 g c ¼ 19:14ð2Þ A, cm3 . A total of 2116 reflections were collected up to 2hmax ¼ 50°, of which 946 were unique (Rint ¼ 0:0598). Absorption corrections (l ¼ 22:835 mm1 ) were applied by integration from the crystal shape, transmission factors ranging from 0.0614 to 0.0190. The crystal is merohedry twin with law of (1 0 0/0 1 0/0 0 )1). The structure was solved by direct methods and refined by full-matrix least-squares on F 2 with an anisotropic approximation using S H E L X -97 [10]. Hydrogen atoms were not located. Metal atom positions correspond to the mixture of Mo and Re atoms. The relative occupancy factors were refined together with the rest parameters without constrains. Final R values: R1 ¼ 0:0378, wR2 ¼ 0:0903 for 808 Fo P 4rðF Þ, R1 ¼ 0:0527, wR2 ¼ 0:0967, GOF ¼ 1:100 for all unique data, relative weights of twin components are 0.313(3) and 0.687(3). 2.1.3. Crystal data for the second crystal (data were collected at room temperature, size: 0.19 0.18 0.12 mm) C6 H4 Cs5 Mo1:64 N6 O2 Re4:36 S8 , M ¼ 2082:81, trigonal crystal system, space group P 3c1, a ¼ 9:838ð3Þ A,
V ¼ 1608:9ð9Þ A 3 , Z ¼ 2, Dc ¼ 4:299 g c ¼ 19:195ð6Þ A, 3 cm . A total of 4051 reflections were collected up to 2hmax ¼ 50°, of which 1240 were unique (Rint ¼ 0:0954). Absorption corrections (l ¼ 23:084 mm1 ) were applied by integration from the crystal shape, transmission factors ranging from 0.9952 to 0.5312. The crystal is merohedry twin with law of (1 0 0/0 1 0/0 0 )1). The structure was solved by direct methods and refined by full-matrix least-squares on F 2 with an anisotropic approximation using S H E L X -97 [10]. As in the first crystal, metal atom positions correspond to the mixture of Mo and Re atoms. The relative occupancy factors also were refined together with the rest parameters without constrains. Hydrogen atoms were not located. Final R values: R1 ¼ 0:0406, wR2 ¼ 0:0765 for 808 Fo P 4rðF Þ, R1 ¼ 0:0678, wR2 ¼ 0:0905, GOF ¼ 1:125 for all unique data. Relative weights of twin components are 0.408(3) and 0.592(3). Crystal data and selected bond lengths for the two crystals are given in the Tables 1 and 2, respectively. Table 1 Crystal data and structure refinements for Cs5 [Re4:21 Mo1:79 S8 (CN)6 ] 2H2 O (1) and Cs5 [Re4:36 Mo1:64 S8 (CN)6 ] 2H2 O (2) Compound
1
2
Chemical Formula Formula weight Space group a (A) c (A) 3 ) V (A
C6 H4 Cs5 Mo1:79 N6 O2 - C6 H4 Cs5 Mo1:63 N6 O2 Re4:21 S8 Re4:36 S8 2068.82 2082.81 P3c1 P 3c1 9.792(3) 9.838(3) 19.14(2) 19.195(6) 1589.7(18) 1608.9(9) Z 2 2 k (A) 0.71073 0.71073 T (K) 211 293 qcalc (g/cm3 ) 4.322 4.299 228.35 230.84 l (cm1 ) RðF Þa 0.0378 0.0406 Rw ðF 2 Þ 0:0967b 0:0905c P P a RðF Þ ¼ jjF j for Fo2 > 2rðFo2 ). Po j jFc jj= jFo P b Rw ðFo2 Þ ¼ f ½wðFo2 Fc2 Þ2 = wFo4 g w1 ¼ r2 ðFo2 Þ þ ð0:053Fo2 Þ2 for Fo2 P 0 and w1 ¼ r2 ðFo2 Þ for Fo2 < 0. P P c Rw ðFo2 Þ ¼ f ½wðFo2 Fc2 Þ2 = wFo4 g w1 ¼ r2 ðFo2 Þ þ ð0:028Fo2 Þ2 2 1 2 2 for Fo P 0 and w ¼ r ðFo Þ for Fo2 < 0.
Table 2 for Cs5 [Re4:21 Mo1:79 S8 (CN)6 ] 2H2 O (1) and Selected bond lengths (A) Cs5 [Re4:36 Mo1:64 S8 (CN)6 ] 2H2 O (2)a Compound
1
2
Re,Mo(1)–Re,Mo(1)#1 Re,Mo(1)–Re,Mo(1)#2 Re,Mo(1)–S(1) Re,Mo(1)–S(2) Re,Mo(1)–S(2)#1 Re,Mo(1)–S(2)#2 Re,Mo(1)–C(1) C(1)–N(1)
2.619(2) 2.6201(14) 2.444(6) 2.449(4) 2.458(4) 2.459(4) 2.151(17) 1.14(2)
2.6244(13) 2.6268(13) 2.443(5) 2.458(4) 2.463(4) 2.4588(4) 2.139(16) 1.14(2)
a
#1: x; y þ 1; z; #2: x þ y 1; x þ 1; z. Symmetry transformation used to generate equivalent atoms.
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Ref. Mean (M–Q)
2.454 2.411 2.457(1) 2.444 2.452(7) 2.455(7) 2.462(3) 2.447(4) 2.452(2) 2.452(2) 2.459 2.415 0.191 0.031 0 0.011 0.013 0.020 0.012 0.028 0.034 0 0.015 0.024
D(M–Q) M–Q
2.399–2.590 2.398–2.429 2.457(1) 2.438–2.449 2.444(6)–2.459(4) 2.443(5)–2.463(4) 2.455(3)–2.467(3) 2.435(4)–2.463(3) 2.431(2)–2.465(2) 2.452(2) 2.452(2)–2.467(1) 2.398(4)–2.422(3) 2.603 2.602 2.666(1) 2.663 2.620 2.626(2) 2.644(2) 2.649(2) 2.649(1) 2.6772(7) 2.685(3) 2.617
Mean (M–M) D(M–M)
0.01 0.01 0 0.002 0.001 0.003 0.006 0.037 0.021 0 0.006 0.005
The concurrent formation of Re4 and Re6 clusters realized in high temperature reactions is known. The study of Re–Te–Cl and Re–Se–Cl systems showed that Re4 clusters are stable below 400 °C, while above this temperature Re6 ones are stable [11]. Up to now Re4 S4 Te4 [12] found in the ternary Re–S–Te system is the only tetrahedral cluster compound stable at 900 °C. Our preliminary study of the interaction of the Re4 S4 Te4 with molten KCN at 850 °C showed that the reaction resulted in rearrangement from a Re4 to Re6 cluster core and formation of a compound isostructural to the known cubic phase Cs3 K[Re6 (l3 -S)6 (l3 Te0:66 S0:34 )2 (CN)6 ] [13] with cell parameters a ¼ 17:80ð1Þ V ¼ 5640 A 3 . Therefore we could expect that hetA, erometallic Re4 x Mox S4 Te4 [9] clusters can be used as starting materials for preparation of new compounds with an octahedral {Re6 x Mox } cluster core. The interaction of the tetrahedral heterometallic cluster compound Re3 MoS4 Te4 under the conditions reported in Section 2 leads to the formation of a compound with an average composition Cs5 [Re4:5 Mo1:5 (l3 S)8 (CN)6 ] 2H2 O. EDAX for a set of single crystals showed that the Re/Mo ratio for them vary in the range Re4:2 Mo1:8 –Re4:5 Mo1:5 , while the Cs/(Re,Mo) ratio is nearly constant. No remarkable amount of tellurium presents in the tested crystals. All crystals in the synthesis have the same shape, hexagonal prisms. It should mean that all of them have the same structure, which was confirmed by measuring the powder diffraction pattern. The X-ray powder diffraction and EDAX data show that we have a typical solid solution with variable
[13] [18] [16] [19] this work this work [20] [20] [20] [17] [17] [7]
3. Discussion
Fig. 1. Anion in 2 (a.d.p. ellipsoids at 50% probability level). Some (Re,Mo)–(Re,Mo), 2.624(1)–2.627(1), av. geometrical parameters (A): 2.626[2]; (Re,Mo)-l3 -S, 2.443(5)–2.463(4), av. 2.455[7]; (Re,Mo)–C, 2.139(16); C–N, 1.14(2).
2.598–2.608 2.597–2.607 2.666(1) 2.662–2.664 2.619(2)–2.620(1) 2.624(1)–2.627(1) 2.641(2)–2.647(2) 2.635(2)–2.672(2) 2.637(1)–2.658(1) 2.6772(7) 2.6818(4)–2.6875(4) 2.614(2)–2.619(2)
S2
M–M
(Re,Mo)1
KCs3 Re6 S8 (CN)6 NaCs3 Re6 S8 (CN)6 K7 [Mo6 S8 (CN)6 ] 8H2 O [Mo6 S8 (PEt3 )6 ] Cs5 [Re4:21 Mo1:79 S8 (CN)6 ] 2H2 O Cs5 [Re4:36 Mo1:64 S8 (CN)6 ] 2H2 O Mo6 S8 (py)6 2py Mo6 S8 (pyrr)6 pyrr Mo6 S8 (pip)6 7pip K6 W6 S8 (CN)6 10H2 O Na6 W6 S8 (CN)6 18DMSO Cs5 Re5 OsS11
S1
Compounds
C1
Table 3 in the octahedral cluster cores {M6 Q8 } Interatomic distances (A)
N1
601
602
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composition, namely, different crystals belonging to the same structural type have variable Re/Mo ratio. To investigate this phenomenon we have selected two crystals for X-ray structural analysis. Both of them appeared to be merohedry twins which is typical for trigonal crystals with hexagonal shape. As expected the structures of both crystals were the same but relative Re/Mo occupancies are different. The cluster anion in the structure of the reported compounds (Fig. 1) has a structure which is similar to well-known [M6 Q8 (CN)6 ]n octahedral chalcocyanide cluster complexes (M ¼ Re, Q ¼ S, Se, Te, n ¼ 3, 4 [13,14]; M ¼ Mo, Q ¼ S, Se, n ¼ 6, 7 [15,16]; M ¼ W, Q ¼ S, n ¼ 6 [17]). As usual, the metal octahedron is surrounded by eight l3 -S ligands forming a S8 cube. Additionally each metal atom is coordinated by the linear CN ligand through the C atom. Average bond lengths are given in Table 3 together with the data for other related compounds. We can see that Re–Re bond are significantly distances in [Re6 S8 (CN)6 ]4 (2.603 A) shorter than Mo–Mo bond distances in [Mo6 S8 (CN)6 ]7 X-ray structural analysis shows that the me(2.666 A). tal–metal bond distances in our heterometallic phase, [Re6 x Mox (l3 -S)8 (CN)6 ]5 , depend on the value of x (2.619(2)–2.620(1) and 2.624(1)–2.627(1) for x ¼ 1:79 and x ¼ 1:63, respectively, Table 3), lying in the range between Re–Re and Mo–Mo. The M–S distances for all [M6 S8 (CN)6 ]n (M ¼ Mo, W, Re; n ¼ 4, 5, 6, 7) anions are almost the same and therefore are not sensitive to N
C
the nature of the metal atoms. The crystal packing is shown in Fig. 2. All the experimental data show that the prepared phase is the solid solution of cesium salts of different [Re6 x Mox S8 (CN)6 ]5 anions. Because the average value of x is close to 1.5 we can expect that we have mixture of [Re5 MoS8 (CN)6 ]5 and [Re4 Mo2 S8 (CN)6 ]5 clusters. The structural and EDAX data show that the Cs/(Re,Mo) ratio is constant. It means that both anions have the same charge, 5. From this it is possible to conclude that the valence electron concentration (VEC) for the [Re5 MoS8 (CN)6 ]5 anion is equal to 24 electrons and this anion is diamagnetic, while [Re4 Mo2 S8 (CN)6 ]5 has a VEC ¼ 23 and is paramagnetic. The measured value of effective magnetic moment, 1.08 MB, is in good agreement with the suggestion that only half of the cluster units contain an unpaired electron. We also have investigated the reaction of other phases in the Re4 x Mox S4 Te4 series [9] with molten KCN and found that under similar experimental conditions similar phases with different Re/Mo ratio were formed. The crystallization with CsCl resulted in phases isostructural to crystals 1 and 2. EDAX analysis made on several crystals gave compositions summarized in Table 4. We can suppose that these phases contain {Re5 Mo}, {Re4 Mo2 } and {Re3 Mo3 } octahedral clusters. In conclusion, interaction of tetrahedral Re4 x Mox S4 Te4 cluster compounds with molten KCN leads to the formation of octahedral heterometallic [Re6 x Mox S8 (CN)6 ]5 cluster anions, x ¼ 1, 2 co-existing in the crystals Cs5 [Re6 x Mox (l3 -S)8 (CN)6 ] 2H2 O. The solubility of these salts opens the way for further study of the chemical properties of Re–Mo heterometallic cluster complexes.
Cs
4. Supplementary data
Fig. 2. Crystal packing in 2. Sulfur atoms are omitted for clarity.
Supplementary data are available from the CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax: +44-1223336033; E-mail: [email protected] or www: http:// www.ccdc.cam.ac.uk) on request, quoting the deposition Nos. 391226 and 391227.
Table 4 Expected and found Re/Mo ratios in Cs5 [Re6 x Mox S8 (CN)6 ] 2H2 O series Starting polymeric solid
Expected Re/Mo ratio in octahedral cluster
Experimental Re/Mo ratio averaged by several crystals
Yield of salt, %
Re3:33 Mo0:67 S4 Te4 Re3 MoS4 Te4 Re2:7 Mo1:3 S4 Te4 Re2 Mo2 S4 Te4
Re5 Mo Re4:5 Mo1:5 Re4 Mo2 Re3 Mo3
Re4:9 Mo1:1 Re4:4 Mo1:6 Re4:1 Mo1:9 Re3:8 Mo2:2
40 56.7 45 15
N.G. Naumov et al. / Polyhedron 23 (2004) 599–603
Acknowledgements This work was supported by the Program ‘‘Universities of Russia’’ of the Education Ministry of Russian Federation, Grant UR.05.01.038.
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