Thermolysis of rhenium carbonyl phosphine complexes Re2(CO)10-n(P(C6H5)3)n (n = 1, 2)

Abstract

Heating Re2(CO)s(ax-L)2 (1) [L = P(C&5)3] in xylene solution in a sealed glass tube at 180-230 OC gives six products of two (CO)&,L, (m = 1, ax-L, n = 0, 4; m = n = 1, ax-L, 5; m = 1, eq-L, n = 1, ax-L, 6 m = 0, n = 2, ax-L, 7). At 160 "C only 2 and 3 are observed. The complex Re2(CO)s(r-H)(r-P(C6H5)2) (8) is obtained by thermolysis of Re,(CO),(ax-L) (9) in xylene solution at 180 OC. Thermolysis of 2 in decalin solution at 240 "C leads to Re3(CO)&-P(C6H5)2)3 (10). 'H and ,'P NMR data have been measured for the newly synthesized compounds. The molecular structures of 2,4, and 10 have been determined from X-ray data collected on an automated diffractometer with monochromatized Mo Ka radiation. Compounds 2 and 4 crystallize in the monoclinic space group P2Jn (No. 14), and 10 crystallizes in P 2 J a (No. 14), with 2 = 4: 2, a = 13.431 (9) A, b = 11.804 (5) A, c = 23.072 (12) A, @ = 102.78 (6)"; 4, a = 16.800 (2) A, b = 12.077 (3) A, c = 23.048 (3) A, @ = 92.82 (1)O; 10, a = 11.670 (3) A, b = 23.151 (14) A, c = 16.327 (3) A, @ = 90.08 (3)". The molecular structure of the diamagnetic compound 2 contains two octahedrally coordinated rhenium atoms with a hydrido-and diphenylphosphido-bridged Re-Re bond (Re-Re = 3.152 (1) A). The p-H position could not be evaluated from a Fourier map. Therefore, the presence of the monohydride compound was shown by the results of 'H high-field NMR measurements. The eq-L ligand in 2 is trans-positioned to the p-P(C,H,), group. The molecular structure of the secondary metalation product 4 possesses two rhenium atoms, each with an essentially octahedral arrangement of the ligands. One rhenium atom is coordinated by four carbonyl groups while the other is coordinated by three carbonyl groups and a triphenylphosphine. The two rhenium atoms are bridged by a quadridentate ligand that is bidentate to each metal atom. The molecule has an extended planar tricyclic ring system that includes the bridging ligand and both metal atoms. A comparison of its bond parameters with those of related rhenium and manganese compounds is given. The molecular structure of 10 shows as a central fragment a three-membered ring of rhenium atoms [average Re-Re = 2.914 (4) A] edged-bridged by diphenylphosphido groups. Each rhenium coordination sphere contains, besides the two trans-positioned p-P ligand atoms, three additional CO groups having a meridional ligand arrangement.types: first, Re2(CO)8,L.(r-H)(p-P(C,H,)2) (n = 1, eq-L, 2; n 2, eq-L, 3); second, (C6H5)2PC6H3(C=O)Re(co)~mLmRe-

μ-Hydrido-μ-dicyclohexylphosphido-bis[dicyclohexylphosphine(tricarbonyl)rhenium]

“…The study of phosphido-bridged homo-and heteronuclear transition metal cluster compounds is of great interest due to their metal-metal bond stabilities under various reaction conditions (Haupt, Balsaa & F16rke, 1988).…”

“…The related unsubstituted compounds (II) and [Re2(#-H)(#-PPh2)(CO)8] (F16rke & Haupt, 1994) show substantially smaller torsion angles, ranging from 2.3 to 6.2 ° (average values). Monosubstituted Mn or Re carbonyl cluster compounds [M2(#-H)(#-PR2)(CO)7-(PL3)], where L3 is HCy2 or Ph3, also exhibit these terminal phosphine ligands in trans positions with respect to the Re--#-P bond (Arif, Jones & Schwab, 1986;Haupt, Balsaa, F16rke, 1988).…”

Notes for Authors

“…In the course of our work on phosphanido-bridged homoand heteronuclear metal-atom cluster compounds (Haupt, Balsaa & F16rke, 1988;Haupt, Heinekamp & F16rke, 1989;F16rke & Haupt, 1993), we isolated the title compound (I) in which a Co--Re bond is symmetrically bridged by two dicyclohexylphosphanido groups.…”

Heterometallatom‐Koordinationsverbindungen Re2(μ‐PPh2)2[mer‐(CO)3]2‐trans‐[InX2(H2O)]2 und neue halogenhaltige drei‐ und vierkernige Rheniumcluster aus Reaktionen zwischen Re2[μ‐PPh2)2(CO)8] und InX3 (X = Cl, Br, I)

“…Solche Temperaturbedingungen erlauben fur das in bestimmten aromatischen Kohlenwasserstoffen geloste Dirheniumdekacarbonyl eine Dissoziation sowohl der Re-Re als auch von Re-CO-Rindungen [6--81. Bei den phosphansubstituierten Dirheniumverbindungen (n = 1 , 2 ) treten zusatzlich noch P-C-und C-H-Bindungsspsltungen unter Bildung von phosphidoverbruckten Hydridodirheniumcarbonylen und orthometallierten Rheniumverbindungen ein [9]. Durch die Wahl des unter solchen Rzaktionsbedingungen thermisch bestiindigeren Edukts Re,(p-PPh,) ,(CO), ohne Metall-Metallbindung wurde fur die Darstellung von Indium(II1) -Rheniumverbindungen ein eleganter Zugang uber eine selektive Offnung von Rhenium-Ligandenbindungen bei gleichzeitiger Zuruckdrangung des Zerfalls von P-C-und C-H-Bindungen erhofft.…”

“…5264 (1) (7) 4677 (8) 4849 (6) 3980 (9) 3 785 ( 7) 2147 (6) 4100 (6) 3670 (6) 3 342 (6) 3 444 (6) 3874 (6) 4638(G) 5301(G) 4G51 (6) 2) 33(2) C ( 3 3 ) 506(1%) l161(9) 8756(9) 35(4) C(34) 47(10) 1G90 (7) 8926 (7) 57 (3) (7) 9338 (7) 65(4) C(41) 1881(13) -1247(10) G889(9) 42(4) C (42) 2241 (14) -6(1O) 5998(11) 55(5) C(44) 2333 (10) iO (8) 5305(8) 81(4) C(45) 4%22(13) 382(9) 8921(9) 43(4) C(4G) 5312(10) 595 (7) 9171(7) 68 (3) 3645 (13) --946(10) 9000(10) 43(5) C(52) 3828(1O) -1546 (7) 9270 (7) G1(4) C(53) -47.5 (7) -631(5) 6978(6) "(4) C(64) -316 (7) -1316(5) 7393(6) 52(5) C(55) -970 (7) -1917(5) 725G(G) 67(5) C(56) --1783 (7) -1833 (5) G703 (6) GO (6) C(61) -1 94% (7) -1147(5) 6288(6) 65(G) C(@2) -1 288 (7) -546(5) 6425(6) 43(4) C(G3) -38 (9) 915(6) 6517(6) 40(4) C(G4) -GO9 (9) 1479 (6) G832 (6)…”