FORMATION OF ANTIFERROMAGNETIC HETERONUCLEAR THIOLATE AND SULFIDE BRIDGED COMPLEXES .1. SYNTHESIS, MAGNETIC-PROPERTIES, AND MOLECULAR-STRUCTURES OF CHROMIUM AND RHENIUM CONTAINING CLUSTERS

The formation of heteronuclear antiferromagnetic complexes and cluster s containing CpCr and Re(CO)(NO) fragments was studied. The antiferrom agnetic adducts Cp2Cr2(mu-SCMe3)2-(mu3-S)Re(CO)2(NO) with cis and tran s (mu3-S)Re(NO) units (3a and 3b, respectively) (3a Cr-Cr 2.777(6) ang strom, -2J = 328 cm-1; 3b Cr-Cr 2.788(3) angstrom, -2J = 328 cm-1) wer e prepared by reaction of the binuclear antiferromagnetic complex CP2C r2(SCMe3)2S (1) and (CO)4(NO)2Re2Cl4 (2) (ratio 2:1) at 40-degrees-C i n benzene or toluene. It was shown that 3a reacts with 1 (ratio 2:1) a t 80-degrees-C in benzene to give the antiferromagnetic cluster CP2Cr2 (mu3-S)2(mu-SCMe3)2Pe(CO)(NO) (6, Re-Cr 2 x 2.940(5) angstrom, Cr-Cr 3 .014(6) angstrom; -2J = 231 cm-1) as the major reaction product and th e paramagnetic tetranuclear compound [CpCr(mu-SCMe3)2(mu3-S)Re(CO)(NO) ]2 (4, mu(eff)/Cr atom = 4.04 mu(B) (291-79 K); Cr-Re 3.129(1) angstro m, Re ... Re 3.6681(5) angstrom) in low yield. 4 can also be prepared by direct thermolysis of 3a at 60-70-degrees-C in toluene and 6 was fo rmed by the conversion of either 2 with 1 (ratio 3:1) at 80-degrees-C in MeCN or of 4 with 1 (ratio 2:1). Refluxing of 3a with P(OiPr)3 (rat io 1:1) and subsequent chromatographic separation yields 4, 6, and a n ew paramagnetic trinuclear complex r(mu-OSCMe3)2(mu3-S)Re2(mu-Cl)(mu-S CMe3)(CO)2(NO)2 (8, mu(eff)/Cr atom = 3.98 mu(B) (291-79 K)) containin g no M-M bonds (Re ... Re 3.270(1) angstrom, Re ... Cr 3.900 (3) and 3 .906(3) angstrom). It is proposed that formation of 4 and 6 proceeds v ia the unstable binuclear remetalation product CpCr(mu-SCMe3)2(mu-S)Re (CO)2(NO)(5). Compounds 3a, 3b, 4, 6, and 8 were characterized by X-ra y analyses. Crystal data: 3a, triclinic, space group P1BAR, a = 10.201 (6) angstrom, b = 11.546(6) angstrom, c = 11.776(7) angstrom, a = 97.1 9(4)-degrees, = 91.45(5)-degrees, gamma = 91.94(5)-degrees, V = 1375(2 ) angstrom3, Z = 2; 3b.0.5C6H6, monoclinic, space group C2/c, a 18.526 (8) angstrom, b 10.184(4) angstrom, c = 16.693(5) angstrom, beta = 97. 28(2)-degrees, V = 3124(2) angstrom3, Z = 4; 4, monoclinic, space grou p P2(1)/n, a = 11.163(3) angstrom, b = 11.977(3) angstrom, c = 14.521( 3) angstrom, beta = 91.320, V = 1941.0(8) angstrom3, Z = 2; 6, monocli nic, space group C2, a = 14.163(3) angstrom, b = 9.934(2) angstrom, c = 8.449(2) angstrom, beta = 93.63(2)-degrees, V = 1240.1(5) angstrom3, Z = 2; 8, monoclinic, space group P2(1)/n, a = 11.946(4) angstrom, b = 12.185(6) angstrom, c = 20.890(8) angstrom, 102.62(2)-degrees, V = 2 967(2) angstrom3, Z = 4.