Triorganoantimon‐ und Triorganobismutderivate von Carbonsäuren fünfgliedriger Heterocyclen Kristall‐ und Molekülstruktur von (C6H5)3Sb(O2C‐2‐C4H3S)2
Authors: Domagala M. , Huber F. , Prexit H. 
Published: January 2011

Inhaltsübersicht. Triorganoantimon‐ und Triorganobismutdicarboxylate R3M[O2C(CH2)n‐2‐C4H3X]2 (M = Sb, R = CH3, C6H11, C6H5, 4‐CH3OC6H4; M = Bi, R = C6H5, 4‐CH3C6H4; n = 0, X = O, S, NH, NCH3. M = Sb, R = CH3, C6H5; M = Bi, R = C6H5; n = 1, X = O, S. M = Sb, R = C6H11, n = 1, X = S; R = 4‐FC6H4, n = 0, X = O, S, NCH3; R = 2,4,6‐(CH3)3C6H2, n = 0, X = O, S, NH) wurden durch Reaktionen von R3Sb(OH)2 (R = CH3, C6H11, 2,4,6‐(CH3)3C6H2), R3SbO (R = C6H5, 4‐CH3OC6H4, 4‐FC6H4) bzw. R3BiCO3 mit den entsprechenden fünfgliedrigen heterocyclischen Carbonsäuren 2‐C4H3X(CH2)nCOOH dargestellt. Auf der Basis schwingungsspektroskopischer Daten wird für alle Verbindungen eine trigonal bipyramidale Umgebung vom M (zwei O‐Atome von einzähnigen Carboxylatliganden in den apikalen, drei C‐Atome von R in den äquatorialen Positionen) vorgeschlagen, ferner eine schwache Wechselwirkung zwischen O(=C) jeder Carboxylatgruppe und M.

Die Kristallstrukturbestimmung von (C6H5)3Sb(O2C–2‐C4H3S)3 stützt diesen Vorschlag. Die Verbindung kristallisiert triklin [Raumgruppe P$1; a = 891,8(14), b = 1058,2(12), c = 1435,6(9) pm, α = 68,53(8), β = 85,47(9), γ = 85,99(11)°; Z = 2; d(ber.) = 1,607 Mg m–3; V(Zelle) = 1255,6 Å3; Strukturbestimmung anhand von 3947 unabhängigen Reflexen (Fo > 3σ(F2o)), R(ungewichtet) = 0,037]. Sb bindet drei C6H5‐Gruppen in der äquatorialen Ebene [mittlerer Abstand Sb–C: 211,1(5)pm] und zwei einzähnige Carboxylatliganden in den apikalen Positionen einer verzerrten trigonalen Bipyramide [mittlerer Abstand Sb–O: 212,0(4) pm]. Aus den relativ kurzen Sb – O(=C)‐Abständen [274,4(4) und 294,9(4) pm] und aus der Aufweitung des dem O(=C)‐Atom nächsten äquatorialen C–Sb–C‐Winkels auf 145,9(2)° [andere C‐Sb‐C‐Winkel: 104,4(2), 109,5(2)°] wird auf schwache Sb–O(=C)‐Koordination geschlossen. Schließlich wird eine Korrelation zwischen dem (+, –)I‐Effekt des Organoliganden R an M (M = Sb, Bi) und der Stärke der M–O(=C)‐Koordination in den Dicarboxylaten R3M[O2C(CH2)n–2‐C4H3X]2 vorgeschlagen.

Triorganoanümony and Triorganobismuth Derivatives of Carbonic Acids of Five‐membered Heterocycles. Crystal and Molecular Structure of (C6H5)3Sb(O2C–2‐C4H3S)2

Triorganoantimony‐ and triorganobismuth dicarboxylates R3M[O2C(CH2)n–2‐C4H3X]2 (M = Sb, R = CH3, C6H11, C6H5, 4‐CH3OC6H4; M = Bi, R = C6H5, 4‐CH3C6H4; n = 0, X = O, S, NH, NCH3. M = Sb, R = CH3, C6H5; M = Bi, R = C6H5; n = 1, X = O, S. M = Sb, R = C6H11, n = 1, X = S; R = 4‐FC6H4, n = 0, X = O, S, NCH3; R = 2,4,6‐(CH3)3C6H2, n = 0, X = O, S, NH) have been prepared by reaction of R3Sb(OH)2 (R = CH3, C6H11; 2,4,6‐(CH3)3C6H2), R3SbO (R = C6H5, 4‐CH3OC6H4, 4‐FC6H4) or R3BiCO3 with the appropriate five‐membered heterocyclic carboxylic acid. From vibrational data for all compounds a trigonal bipyramidal environment around M (two O atoms of unidendate carboxylate ligands in apical, three C atoms (of R) in equatorial positions) is proposed and also an additional weak interaction of O(=C) of each carboxylate group and M.

The crystal structure determination of Ph3Sb(O2C–2‐C4H3S)2 gives additional prove to this proposal. It crystallizes triclinic [space group P$1; a = 891.8(14), b = 1058.2(12), c = 1435.6(9) pm, α = 68.53(8), β = 85.47(9), γ = 85.99(11)°; Z = 2; d(calc.) = 1.607 Mg m–3; Vcell = 1255.6 Å3; structure determination from 3 947 independent reflexions (Fo > 3σ(F2o)), R(unweighted) = 0.037]. Sb is bonding to three C6H5 groups in the equatorial plane [mean distance Sb–C: 211.1(5) pm] and two unidentate carboxylate ligands in the apical positions of a distorted trigonal bipyramid [mean distance Sb–O: 212.0(4) pm]. From the relatively short Sb–O(=C) distances [274.4(4) and 294.9(4) pm] and from the enlarged value of the equatorial C–Sb–C angle next to the O(=C) atom [145.9(2)°; other C–Sb–C angles: 104.4(2), 109.5(2)°] additional weak Sb–O(=C) coordination is inferred. Finally a correlation between the (+, –) I‐effect of the organic ligands It at M and the strength of the M–O = C interaction is suggested.