Mixed rhenium–gold polyhydrides that contain ReAu and ReAu₂cores

Steric effects in polypyrazolylborate ligands. Poly(3-isopropylpyrazolyl)borates: ligands of intermediate steric requirements

“…-1514 0020-1669/89/1328-1091 SOI. 50/0 new ligands reported here, with a 3-isopropyl group (1), show H characteristics of both of these ligands: limited formation of the M(HB(3-Rpz)3)2 complexes and accessibility of the metal ion. In addition the synthesis and coordination chemistry of another new derivative, [HB(3-;'-Pr-4-Br-pz)3]~, with a bromine atom in the 4-position of the pyrazolyl ring, are presented.…”

“…2,3,[15][16][17] The geometry about the Co inner coordination sphere may be described as a flattened tetrahedron. N(12)-Co-N( 22) 84.45 (6) N( 12)-Co-N(32) 88.77 (6) N( 22)-Co-N(32) 88.58 (6) Co-N(12)-N(l 1) 113.4(1) Co-N(12)-C(13) 138.2 (1) N(12)-N(l 1)-C(15) 109.8( 2) N( 12 In Figure 4 it can be seen that, for two of the rings of each ligand, the isopropyl group is in the 3-position, whereas for the third ring the isopropyl group is in the 5-position. It can also be seen that these groups are oriented such that two of them bisect the pyrazolyl ring, whereas the third ring (with the 5-isopropyl group) has an intermediate arrangement.…”

“…(ii) Re(02CCH3)(C0)2(PPh3)2 (1). Diethyl ether (50 mL) was added to the dark green filtrate from part A(i), and the resulting solution was slowly evaporated under a gentle stream of nitrogen until the volume was approximately 5 mL.…”

Rhenium Dihydrogen Complexes with Isonitrile Coligands: Novel Displacement of Chloride by Hydrogen

“…The products, however, would not likely be dihydrogen complexes. Walton and co-workers 33 have prepared both [Re(CNR)-(dppe) 2 H 2 ] + (R ) Me, tBu, 2,6-Me 2 C 6 H 3 ) and [Re(CNtBu) 2 -(PPh 3 ) 3 H 2 ] + with the BF 4 -counterion (see Table 5). The large J HP coupling constants of the hydrides strongly imply that these species are dihydrides and not dihydrogen complexes.…”

“…37 This complex is reported to exhibit a large hydrogenphosphorus coupling (J HP ) 20 Hz), which is very suggestive of a dihydride structure. 33 The use of the more electron donating PMe 3 ligands can only be expected to further stabilize the dihydride structure. In fact, the coupling constant does increase significantly (J HP ) 28.6 Hz).…”