When you are not sure about the data structure you are creating use Data::Dumper to document it for you:

use strict;
use Data::Dumper;
my $key = 4711;
my $value = "fubar";
my @jobs;
push @jobs, {$key=>$value};
print Dumper \@jobs;

___OUTPUT___

$VAR1 = [
          {
            4711 => 'fubar'
          }
        ];
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