CCL: Bonds dissapearing in optimized structure

From: "Gabriela Arias" <gabriela.arias _ yorkmail.cuny.edu>
Subject: CCL: Bonds dissapearing in optimized structure
Date: Mon, 20 Dec 2010 15:26:22 -0500
 Sent to CCL by: "Gabriela  Arias" [gabriela.arias _ yorkmail.cuny.edu]
 Dear CCL subscribers:
 I am trying to optimize a structure in which Zn is octahedrally coordinated with
 two citrate molecules. When I optimize this structure the bonding between Zn and
 the two citrate molecules disappears. I know this complex is possible since I
 got the structure from the authors of a published crystallography paper. This is
 my input:
 %chk=octacomplex.chk
 %mem=70MW
 %nprocshared=2
 # opt rb3lyp/6-311+g(d,p) guess=(local,save) geom=connectivity
 Title Card Required
 -4 1
 C 0.00000000 0.00000000 0.00000000
 O 0.00000000 0.00000000 1.44957233
 H 0.84063190 0.00000000 1.70043798
 C -1.45846423 -0.22289327 -0.45896769
 O -2.29631461 -0.61293155 0.41986215
 O -1.72466070 -0.03349046 -1.65301136
 C 0.88489416 -1.13110147 -0.54914157
 H 0.78695471 -1.14345589 -1.51425010
 H 1.80867833 -0.90423719 -0.35833379
 O -0.35546025 -2.74486386 0.71897856
 C 0.55671496 1.33042743 -0.51066400
 H 1.47945129 1.40232696 -0.21933614
 H 0.56235260 1.30216071 -1.48011487
 C -0.17273032 2.58702456 -0.08041309
 O -1.40015281 2.55436371 0.08757794
 O 0.51874797 3.64592327 0.04721742
 C -2.70592252 -3.08341975 4.08248350
 O -2.70592252 -3.08341975 2.63291117
 H -3.54664302 -3.08346576 2.38205127
 C -1.24759139 -2.86049159 4.54141854
 O -0.40960791 -2.47048821 3.66262135
 O -0.98130632 -3.04984838 5.73545646
 C -3.59086117 -1.95223738 4.63158667
 H -3.49287722 -1.93996386 5.59673360
 H -4.51473395 -2.17914766 4.44078464
 C -3.34303653 -0.55032925 4.12272545
 O -2.35059538 -0.33852100 3.36347229
 O -4.12000079 0.34887973 4.48811035
 C -3.26277058 -4.41381229 4.59311486
 H -4.18537380 -4.48574672 4.30181964
 H -3.26836372 -4.38562647 5.56260412
 C -2.53332530 -5.67040942 4.16286395
 O -1.30581420 -5.63770256 3.99486717
 O -3.22475909 -6.72938904 4.03527183
 Zn -1.35300556 -1.54173288 2.04124462
 C 0.63698091 -2.53305560 -0.04027460
 O 1.42338885 -3.44322386 -0.41004057
 1 2 1.0 4 1.0 7 1.0 11 1.0
 2 3 1.0 35 1.0
 3
 4 5 1.0 6 2.0
 5 35 1.0
 6
 7 8 1.0 9 1.0 36 1.0
 8
 9
 10 36 1.0 35 1.0
 11 12 1.0 13 1.0 14 1.0
 12
 13
 14 15 2.0 16 2.0
 15
 16
 17 18 1.0 20 1.0 23 1.0 29 1.0
 18 19 1.0 35 1.0
 19
 20 21 2.0 22 2.0
 21 35 1.0
 22
 23 24 1.0 25 1.0 26 1.0
 24
 25
 26 27 1.0 28 2.0
 27 35 1.0
 28
 29 30 1.0 31 1.0 32 1.0
 30
 31
 32 33 2.0 34 2.0
 33
 34
 35
 36 37 2.0
 37
 1 2 1.0 4 1.0 7 1.0 11 1.0
 2 3 1.0 35 1.0
 3
 4 5 1.5 6 2.0
 5 35 1.0
 6
 7 8 1.0 9 1.0 36 1.0
 8
 9
 10 36 1.5 35 1.0
 11 12 1.0 13 1.0 14 1.0
 12
 13
 14 15 2.0 16 2.0
 15
 16
 17 18 1.0 20 1.0 23 1.0 29 1.0
 18 19 1.0 35 1.0
 19
 20 21 1.5 22 2.0
 21 35 1.0
 22
 23 24 1.0 25 1.0 26 1.0
 24
 25
 26 27 1.5 28 2.0
 27 35 1.0
 28
 29 30 1.0 31 1.0 32 1.0
 30
 31
 32 33 2.0 34 2.0
 33
 34
 35
 36 37 2.0
 37
 Any help would be greatly appreciated.
 Best regards,
 Gabriela Arias