A descriptor system and principles for numbering closed boron polyhedra with at least one rotational symmetry axis and one symmetry plane

Abstract

A method for uniquely describing closed, fully triangulated, boron polyhedra with 4-24 vertices based on currently accepted procedures for numbering of coordination and boron polyhedra is proposed. Minor refinements and extensions to the numbering principles for closed polyhedra are suggested. more than one polyhedral structure for each [B"H"]2" composition. Therefore, the descriptive prefix "clovo",3 later modified to "closo-",4 derived from the Greek word for cage, ß , was sufficient to identify these polyhedral structures and to distinguish them from the nonclosed, or open, polyboron hydride structures already known.5The development of metallopolyboron chemistry has led to a need for a more extensive and definitive method for describing closed polyhedral structures. Incorporating metal atoms into polyboron hydride systems substantially increased the variety of closed polyhedral structures. Metallopolyboron chemistry led to the preparation of polyhedra with more than 12 vertices, the so-called supraicosahedra,6,7 which, in turn, stimulated postulation of much larger polyhedra, containing as many as 32 vertices.8 New structures for polyhedra with less than 12 vertices were also found in metalloboron systems.9(1) (a) Chemical Abstracts Service, (b) The University of Chicago; Camille and Henry Dreyfus Teacher-Scholar.(2) M. F.

Nomenclature for boranes and related species (IUPAC Recommendations 2019)

“…The calculated deltahedral structure for the 16-vertex closo-[B 16 H 16 ] 2− structure is an octacosahedron (28 faces) with T d symmetry. This structure has been observed in a recently reported closed metallaborane cage containing a {Rh 4 B 12 } core [29] with a Powell descriptor [23] of [T d -(1v 6 633v 6 3)-Δ 28 -closo]. This is shown in Fig.…”

“…The calculated deltahedral structure for the 15-vertex [B 15 H 15 ] 2− is the hexacosahedron (26 faces) with D 3h symmetry. This structure has been observed in species such as (η 5 -C 5 Me 5 Rh) 2 B 13 H 13 [28], and 1,4-μ-[CH 2 ] 3 -7-(η 6 -1isopropyl-4-methylbenzene)-1,4,7-C 2 RuB 12 H 12 [34], and the cage structure corresponds to a Powell descriptor [23] of [D 3h -(333v 6 33)-Δ 26 -closo]. The numbering scheme for these closo structures is shown in Fig.…”

“…3) [33]. The tetracosahedron has the Powell [23] descriptor [D 6d -(1v 6 661v 6 )-Δ 24 -closo]. The largest known heteroborane to date, 2,3-μ-[CH 2 ] 3 -closo-2,3-C 2 B 12 H 12 [27], has this structure, and can be named by bridging nomenclature as 2,3-(propane -1,3-diyl) [D 6d -(1v 6 661v 6 )-Δ 24 -closo]-2,3-dicarbatetradecaborane (14).…”

“…Recommendation 19: A new system for the description of closed (closo) supra-icosahedral polyhedral shapes based on a published method [23] is recommended. Closed (closo) 13-to 16-vertex polyhedra are shown in Fig.…”

Trichloro(9-methylguaninium)platinum(II) hydrate and 9-methylguaninium hexachloroplatinate(IV) dihydrate: synthesis and structure

“…-3233 (8) 4847 (5) -2361 (9) 4995 (5) -992 (9) 5805 (6) -597 (10) 3723 (6) 954 (9) 3692 (6) 3547 (10) 0 0 1989 (1) 296 (1) 933 (1) 1401 (1) (9-MeGuaH)PtC1,.2H2 0 491 (1) -2296 (1) 5251 (4) -3695 (5) 2854 (4) -6556 (5) 5698 (4) -1888 (4) 4386 (4) -1700 (4) 2863 (4) -4911 (5) 2534 (4) -3760 (4) 6242 (4) 45 (5) (6) 190 (5) 2874 (5) -869 (6) 2135 (5) 3022 (6) 2065 (6) 1667 (6) -229 (6) -1117 (6) 578 (6) 3999 (7) Figure 3. Interatomic bond distances and angles: heavy characters for (9-MeGuaH)PtC13.H20; light characters for (9-Me-G U~H )~P~C I~.…”