Einkristall‐RöntgenStrukturanalysen von Verbindungen mit einer kovalenten Metall‐Metall‐Bindung. VII. Die Kristall‐ und Molekülstruktur von dimeren Halogenobis‐ (pentacarbonylrhenium)indium(III), [(Re(CO)₅)₂In(μ‐X)]₂ (X = Cl, Br, I)

Abstract

[(Re(CO)5)2In(μ‐X)]2 kristallisiert für X = Cl und X = Br monoklin, Raumgruppe P21/c, mit den Gitterkonstanten X = Cl: a = 10,540(6), b = 12,961(7), c = 26,071(12), β = 106,3(1), Z = 4; X = Br: a = 10,548(9), b = 13,108(7), c = 26,192(15), β = 106,0(2), Z = 4 und für X = I triklin, Raumgruppe P1, mit den Gitterkonstanten a = 10,739(2), b = 7,160(1), c = 13,647(1) Å, α = 68,65(9), β = 71,89(9), γ = 65,52(9)°, Z = 1. Das zentrale Molekülfragment besteht aus einem planaren In2X2‐Ring mit mittleren In—X‐Abständen von X = Cl: 2,624(6) Å, X = Br: 2,764(3) Å und X = I: 2,986(2) Å und den Winkeln In—X—In/X—In—X, X = Cl: 97,2(2)°/82,8(2)°, X = Br: 94,8(1)°/85,2(1)° und X = I: 96,47(5)°/83,53(5)°. An die Indiumatome sind jeweils zwei Re(CO)5‐Gruppen so gebunden, daß sich für das Indium eine verzerrt tetraedrische Umgebung ergibt. Die mittleren In—Re‐Bindungsabstände betragen: X = Cl: 2,797(2), X = Br: 2,796(2) und X = I: 2,811(2) Å. Die Rheniumatome besitzen oktaedrische Koordination.

Alkylindium Subhalides Derived from the Tetrahedral Indium(I) Cluster Compound [In4{C(SiMe3)3}4]

“…[13] The In À Br distances (267.7 to 274.0 pm) are in the normal range for bridging bromine atoms. [18,19] They are little shorter than those of the In 4 Br 2 cluster compound 3 discussed before.…”

“…Similarly, the intramolecular Cl´´´Cl distances (367.4 pm) correspond to the sum of the van der Waals radii (340 to 380 pm). [16] Many organoelement compounds bearing In-Cl-In bridges have been described, [17,18] the InÀCl bond lengths observed for 2 (259.1 to 265.3 pm) are in the normal range. As observed in most secondary products of 1, the InÀC bond lengths are a little shorter than those of the cluster compound 1 (221 compared to 225 pm of 1).…”

“…The distances of the m 2 -bridging bromine atom to indium (278.0 pm) are in accordance with standard values of organoelement compounds. [18,19] The InÀBr distances to the m 3 -bridging bromine atom are much longer (In3ÀBr1 292.7 pm; In2/In2'-Br1 303.6 pm). To the best of our knowledge, a comparable m 3 -situation has not been observed before in organoelement indium chemistry.…”

Coordination chemistry of group 13 monohalides

“…These include systems featuring sterically less encumbered transition metal fragments which adopt dimeric structures of the type [(L n M) 2 E-(m-X) 2 E(ML n ) 2 ] or related polymeric architectures. 70,[81][82][83][84][85] Mononuclear systems can be isolated in such cases by the additional coordination of a Lewis base at the Group 13 centre. 83,[86][87][88] By contrast, simple tri-coordinate systems of the type [L n M] 2 -(m-EX) are surprisingly uncommon, 70,[89][90][91] with the tendency of such systems to oligomerize via E-X-E bridges being modulated by bulkier ancillary ligands, or by the electrostatic repulsion brought about by a net overall charge (as in the cases of [{(OC) 5 Cr} 2 (m-EX)] 2À , EX ¼ InBr, TlCl, TlBr, TlI).…”