Open cluster configurations of [1,1-(PPh3)2-1-H-1,2,4-IrC2B8H10] and other formally Wadian 24-electron 11-vertex species

Abstract

In order to establish the suggestion arising from the assignment of the cluster 11B and 1H NMR shielding behavior, namely, that the title compound (I) is not a closo species, a single‐crystal X‐ray diffraction analysis is carried out (space group P21/c, Z=4).

Theisonido-Metalladicarbaborane [1,1,1-H{P(CH3)3}2-6-Cl-1,2,4-IrC2B8H9]

“…Direct thermolysis of the unsubstituted analogue of compound (II) has been shown to give the corresponding isonido compound in ca 25% yield (Bould, Rath & Barton, 1996). The structural features of compound (II) are comparable to those of the unsubstituted cage species [(PPh3)aHIrC2BsHI0] reported previously (Nestor et al, 1989). The shape of the four-membered open face (Irl-C2-C4-B7) is almost identical in the two species, the averages of the angles at the four corners for the two molecules of (II) being 97.3 (7), 108.2 (9), 82.6 (5) and 70.2(5) ° for C2, C4, B7 and Irl, respectively, and for [(PPh3)2HIrC2BsHI0] they are 96.3(4), 107.2(5), 84.8(4) and 69.1 (3) °, respectively.…”

“…The cluster is observed to be of the isonido type, similar to the triphenylphosphine-ligated analogue [(PPh3)2-HIrC2B8H~0] first synthesized by Jung & Hawthorne (1980) directly from [IrCI(PPh3)3] and NaC2B8Hll, and described from the NMR data as a fully closed species, (III), but which was subsequently shown by ThorntonPett & Kennedy (Nestor et al, 1989) to contain a four-membered Irl-C2-C4-B7 open face. The principal feature of the compound described here, in addition / ~ r--, C~-C21 C1~ 1 Fig.…”

Unusual cationic rhodathiaboranes: synthesis and characterization of [8,8,8-(H)(PR3)2-9-(Py)-nido-8,7-RhSB9H10]+and [1,3-μ-(H)-1,1-(PR3)2-3-(Py)-isonido-1,2-RhSB9H8]+

“…This structural motif can be formed by a simple diamondsquare process in a canonical closo-structure based on an octadodecahedron, giving a more open structure that is usually classified as isonido. [48][49][50][51][52][53][54] In the neutral cluster [Fig. 6(d )], the Rh-B lengths of boron vertices, 4 and 5, flanking the sulfur atom, lie just on the upper part of the bonding limit that leads to the generation of a triangular closo-face.…”

Ten-vertex metallaborane chemistry: facile, thermally induced, nido→isocloso cluster-closure oxidation reactions in iridadecaborane clusters

“…Elements of the preference for the C,,-based convex-hexadecahedral structure over that of the bicapped-Archimedian antiprism could also derive from the longer bonding distances and greater co-ordination numbers available to the d-block transition elements relative to those of boron. Examples of seven-co-ordinate boron are rare though it may be found in the (probably unstable) 26 connected boron vertex would probably be less stable than one with four-and five-connected vertices whereas a transition metal, with its greater electrolobal expansion power, may accomodate all these connectivities. The complete capping of an urachno type geometrical structure is required to generate the high connectivities observed in the isocloso clusters: an arachnotype fragment will have more orbitals available in the metalborane overlap region than a nido one, and so in this approach would be better able to accommodate the four-orbital overlap that would be required for this 'isocloso' hypothesis.…”