BIS(DIETHYL SULFIDE)BIS(2,4,6-TRIMETHYLPHENYL)IRIDIUM(II) AND RELATED-COMPOUNDS

The interaction of mer-IrCl3(SEt2)3 with Mg(mes)2(thf)2 [mes = mesityl (2,4,6-trimethylphenyl), thf = tetrahydrofuran] in Et2O-thf gives trans-Ir(mes)2(SEt2)2 1. With PMe3 1 gives trans-Ir(mes)2(PMe3)2 2; both compounds are paramagnetic. With NO, 2 reacts to form the formally iridium(III) complex Ir(mes)2(NO)(PMe3)2 4 that has a bent IrNO group, while H-2 gives the known hydride IrH5(PMe3)2. With CO 1 forms the square iridium(I) complex Ir(mes)(CO)2(SEt2) 3. The trans-square planar molecules of compound 1 lie on centres of symmetry; Ir-S and Ir-C 2.298(4) and 2.09(1) angstrom, respectively, with a unique S-Ir C angle of 88.2(3)-degrees. Molecules of 2 are also trans square planar, but lie in general positions; Ir-P 2.302(4), 2.305(4) angstrom, Ir-C 2.097(9), 2.112(9) angstrom and P-Ir-C 89.6(3)-90.5(3)-degrees. The crystal structure of 4 contains two crystallographically independent molecules, both of which lie on two-fold axes, coincident with the Ir N bond. The geometry is slightly distorted square pyramidal; N-Ir-P and N-Ir-C 91.7(2) (x 2) and 99.1(3), 99.3(3)-degrees, respectively. The Ir-N, Ir-P and Ir-C bond lengths are 1.90(1), 1.91(1); 2.324(5), 2.328(4); and 2.186(9), 2.182(12) angstrom, respectively. The bent Ir-N-O system [133.7(10) and 133.4(8)-degrees] is disordered over two sites related by the two-fold axes, but in a single molecule is fixed in one position and believed to associate, via O ... P interaction, with the phosphorus atom of one phosphine.